u c 
 
 343 
 
 AS 
 
 MOTOR TRANSPORT 
 CORPS 
 
 EXECUTIVE DIVISION 
 TRAINING BRANCH 
 
 « 'v 
 
 whSHifiGrm, D. c 
 
 Vugust, 1919 
 
 fonM MX0-»30 
 
 aovenii ■>■ p*jT pniN-^'NG cfficl 
 

 ic-i^"-::- 
 
 Glass JLLiL3jJlL__ 
 
MOTOR TRANSPORT 
 CORPS 
 
 T 
 
 EXECUTIVE DIVISION 
 TRAINING BRANCH 
 
 WASHINGTON, D. C. 
 August, 1919 
 

 \^ 
 
 \'\ 
 
 p; o* S>. 
 
 DEC 2S 
 
TENTATIVE MANUAL OF INSTRUCTION. 
 
 MOTOR TRANSPORT CORPS. 
 RESERVE OFFICERS' TRAINING CORPS UNITS. 
 
 CONTENTS. 
 
 HKI.I) OI'KKATIONS. 
 
 Page. 
 
 Lecture I. The Motor Transport Corps 7 
 
 II. The Motor Transport Company and The Motorcycle Company- 13 
 
 III. General principles of convoy 21 
 
 IV. Care of equipment 33 
 
 V. Signals and road rules 47 
 
 VI. Map reading r 59 
 
 VII. Iv<iading 'ii 69 
 
 Ylll. Convoy problem 79 
 
 IX. Knotting and splicing 83 
 
 X. Teclinical inspection 89 
 
 CONVOY I'KACTICK. 
 
 ExERciSK I. stationary field drill 99 
 
 II. Road operations in .sections 99 
 
 III. Night oi>eratioiis in company formation KMi 
 
 IV. Night oiierations . KM) 
 
 V. Field jtrohlcni in nia]> reading 10() 
 
 VI. General review and iiri>l)lem i 101 
 
 VTT. Preparation lor formal inspe.ction 101 
 
 ki.k.\ii:nt.\uv Ai'ToxforivE engineering. 
 
 Lectukk 1. Tile uasoline engine 1(1.") 
 
 II. Types of motors 111 
 
 III. Timing and balancing : 113 
 
 IV. Ignition 117 
 
 \'. Fuel systems 12.") 
 
 VI. ("lurches 1,S3 
 
 A'll. Transmissions 1.3.") 
 
 VIIT. The drive 139 
 
 IX. The ditVerential 143 
 
 X. Running gear 147 
 
 XI. Tlie motorcycle 153 
 
 Labi>ratory exercise specifications 157 
 
 3 
 
TENTATIVE MANUAL, OF INSTRUCTION. 
 
 Supplementary List of Resee\^ Officers' Training Corps, Training Material. 
 INSTRUCTION CHARTS. INSTRUCTION CHARTS — Continued. 
 
 No. 1. Location cliart. 
 
 2. Power transmission. 
 
 3. Four-stroke-cycle engine. 
 
 4. Engine (four - cylinder, side 
 
 view). 
 
 5. Engine (T-head, front view). 
 
 6. Engine (V-type, front view). 
 
 7. Pistons, connecting rods, piston 
 
 pins. 
 
 8. Valves, camshafts, exhaust. 
 
 9. Cooling. 
 
 10. Lubrication. 
 
 11. Bearings (engine, shims, etc.). 
 
 12. Bearings (ball, roller, thrust). 
 
 13. Simple carburetor. 
 
 14. Carburetors (Ball and Ball and 
 
 Rayfield). 
 
 15. Carburetors (White and Cadil- 
 
 lac). 
 
 16. Carburetors (Stromberg and 
 
 Stewart). 
 
 17. Carburetors (Zenith and Mar- 
 
 vel). 
 
 18. Carburetors (U.S.A. and Pack- 
 
 ard). 
 
 19. Stewart vacuum tank. 
 
 20. Clutches. 
 
 21. Dodge transmission. 
 
 22. Brakes. 
 
 23. Brakes (equalizers, etc.). 
 
 24. Steering (drag links, etc.). 
 
 25. Steering (post assemblies, con- 
 
 trols). 
 
 26. Rear axles. 
 
 27. Rear axles. 
 
 No. 28. Governors. 
 
 29. Springs and tires. 
 
 30. Ignition (magnetos). 
 
 31/ Ignition (condensers, timers 
 and breakers). 
 
 32. Ignition (distributors and 
 
 spark plugs). 
 
 33. Ignition (Dodge and Cadillac 
 
 commutator and distribu- 
 tor). 
 
 34. Starting and lighting. 
 
 35. Cadillac electrical system. 
 
 36. Dodge electrical system. 
 
 37. Standardized B truck electrical 
 
 system. 
 
 38. Storage batteries and hydrom- 
 
 eter. 
 
 39. Four-wheel drive. 
 
 40. Motorcycle. 
 
 41. Motorcycle. 
 
 42. Miscellaneous. 
 
 MOVING-PICTURE FILMS. 
 
 No. 1. Field operations (complete). 
 2. Maintenance operations (in 
 preparation). 
 
 TRAINING MAPS. 
 
 1. Economic highway survey. 
 
 2. Transcontinental routes. 
 
 3. Gettysburg quadrangle. 
 
 CONVOY CHARTS. 
 
 No. 1. Preparatory formations. 
 2, Troop loading and signals. 
 
MOTOR TRANSPORT CORPS 
 
 R.O.T.C. UNITS 
 
 FIELD OPERATIONS 
 
FIELD OPERATIONS. 
 
 LECTURE I.* 
 
 THE MOTOR TRANSPORT CORPS. 
 
 The use of nioloi- vehick's in the United States Army extends back 
 to 1903. Avlien there were a few ])assen<rer aiitoinohiU's u>ed. ])rinci- 
 pally in Washinirton and at tlie headcpiarters of territorial depart- 
 ments. In 10(H) six motor ears were sni)plied to the army of pacifi- 
 cation in C^uba, and (hirino; the followino; year, 1907. a few motor 
 trucks were purchased, principally for use at the supply depots of 
 the Quartermaster Dejiartment. A few trucks continued to be 
 purchased for the same purposes from year to year until, in 1912, a 
 consistent etfort was made to collect data on the upkeep of motor 
 trucks, to enable the Army to take advantage of the then I'ajiidly 
 develoi)ino: automotive industry in the LTnited States. 
 
 In 191"J the Quartermaster Corj:)s prei)ared the first aenerai sj)ecifi- 
 cations for motor trucks, and in the fiscal year 1914 these specifica- 
 tions, amended to that date, jjoverned all purchases nuide. Theses 
 specifications are quite interestinjj at the present date. They stated, 
 in part, as follows: ''The Quartermaster Corps has adopted general 
 specifications for an automobile tiuck which ])rovides for a maximum 
 wei<>ht of ."i.OOO pouiuls for truck complete, and the carrying- cai)acity 
 has been fixed at l\ tons, with a safe overload of 20 per cent." It is 
 seen ri<iht here where motor transi^ortation has been infiuenced by the 
 old waii'(>n trans})ortati()n of the Army. That is, the capacity of its 
 stan(hird truck at that time was made the same as that of the stand- 
 ard 0-mule escort wajron. This old wagon was a splendid vehicle 
 that had demonstrated its value ever since the Civil War. and was 
 admirably suited for the poor roads and undeveloped comitiy that 
 it was used on since that time. Fi'om this point, by degrees, the 
 present standard truck was developed, and the Army has been given 
 a vehicle far l)ett<M' suited to its needs than any connuercia] \(>hicle. 
 and e(|ual to any of them in efficiency. 
 
 During these years, first the Quartermaster Department, and later 
 the Quartermaster Corps, handled the motor Achicle business of the 
 Army through its Transportation Division although othei- branches 
 of the service, for instance, the Engineers, Signal (^orps. Ordnance, 
 and ^fedical Corps, ])urchased some motorized equipment for their 
 own special needs. 
 
 The slow de\elo|)ment of motoi' ti ansportalion in the American 
 Army, prior to 1910. was due to three factors. First, the Army was 
 called upon for very little mobile operation. Second, in such field 
 
 * The Instructor should supplement all lectures by reference to " Manual of the Motor 
 Transport" as propart'd for iIk- Ami-ricnn KxiMMlitioiiaiy IVncos. 
 
8 TENTATIVE MANUAL, OF INSTRUCTION. 
 
 operations as it did conduct animal transportation sufficed. Third, 
 experience with motor vehicles had been confined largely to depots 
 and army posts, and in this work, necessarily of a short haul nature, 
 motor vehicles could not compete with animal transportation in the 
 matter of expense, and this fact more than any other handicapped 
 the Army in asking appropriations from Congress for motor vehicles. 
 
 In March. 1916, it became necessary to "equip an adequate military 
 force to cross the Mexican border for the capture of the bandits who 
 had raided the town of Columbus, N. Mex. Pursuant to a request 
 from the Southern Department, the Quartermaster General's Office 
 purchased the necessary vehicles for two truck companies. The 
 trucks were of 1^-ton capacity, and to man these trucks, since no 
 jDrovision existed in the Armj'^ at that time for enlisted men as 
 drivers, civilian personnel was hired at the factories where the trucks 
 were manufactured. There were at first but tAvo complete truck 
 companies organized in the United States. These two companies, 
 one from the Jeifrey Motors Co., Kenosha, Wis., and the other from 
 the White Motors Co., Cleveland, Ohio, left March 15 and 16 and 
 went by special train to Columbus, N. Mex. They were rapidly 
 followed by other truck companies organized in the same waj^ Each 
 truck comi^any was equipped with the necessary tank trucks for 
 carrying gasoline, oil, and water, and with two passenger cars. 
 
 With the experience of the Mexican border operations, under their 
 severe conditions, it is apparent that many faults were developed in 
 some of the commercial trucks in use. Some of these faults were of 
 minor character which could be easily corrected, while others were of 
 a much more serious nature and required notice in considering design 
 of trucks. It was found, however, that the provisions of the speci- 
 fications issued by the Quartermaster General's office were most suit- 
 able under these conditions. The various truck manufacturers sent 
 their engineers to study these difficulties, with a view to making 
 recommendations for their improvement and their observations 
 and recommendations proved of great value in the standardization of 
 trucks for military service. 
 
 On June 30, 1916, vehicles for 15 motor truck companies, consist- 
 ing of 27 cargo trucks, all l|-ton capacity, each with necessary 
 auxiliaries, had been purchased and were in operation along the Mexi- 
 can border, or in the vicinity thereof, ready to be placed in opera- 
 tion. These companies operated from Columbus, N. Mex., to a point 
 more than 300 miles beyond the border. It was found that even over 
 the rough country Avhich these trucks traveled, they averaged some- 
 what more than 80 miles per day, in some instances as high as 90 
 miles. Roads, as they existed in that country, were beyond com- 
 parison and it was necessary to make fresh tracks over the prairie 
 for operation of these vehicles. 
 
 In a report made at that time, the following extract is of interest : 
 
 "Among officers of experience Avith motor trucks, it is known that 
 speed is the greatest menace to the successful operation of the truck, 
 It was the hardest thing to control, far greater than anything else 
 in connection Avith motor trucks." 
 
 The experience gained by officers of the Army in operation of 
 motor truclvs and as managers of truck trains on the Mexican border 
 
FIELD OPERATIONS. 9 
 
 Ava.s of greatest value in enabling them to handle this line of trans- 
 portation during the World AVar. 
 
 During this pericxl the Ottice of the Quartermaster General con- 
 tinued its efforts, in conjunction with the (Society of Automotive 
 Engineers, manufacturers and othei- (iovernment departments, to 
 •develo}) specifications for motor trucks with a view to making 
 •changes that would lonform to the exact needs of the Government. 
 
 The use of trailers in conjunction with motor trucks in the very 
 Tougli country of ^Icxic<i, through which motor transportation oper- 
 ated, was considered unsatisfactory. Nevertheless, where specially 
 designed tractors were used, trailers were very satisfactory. This 
 is reallv the i)lace thev shoidd occupy in the transport problem. 
 
 After the United States entered the AVorld War. the first motor 
 transport unit to eml»ark was the First Supply Train, consisting of 
 four comi)anies with hcadfjuarters detachment, oi'ganized at Fort 
 Sam Houston. Tex., in May, 1917. 
 
 This connnand embarked for Fiance in June. 1*.»IT. arri\ iug on tlie 
 ■23d of the same month, and formed the beginning of what developed 
 into the extensive ^lotor Transport Corps of the American Expedi- 
 tionary Forces. At this time, motor transportation was still handled 
 by the Quartermaster of the Expeditionary Forces and in August, 
 1917. his oflice submitted an estimate of the motor transport per- 
 sonnel that would be necessary for an army of .") cor|)s or 30 divisions. 
 This estimate was about 40,000 men and. in spite of the limited ex- 
 perience on which it was based, it was only about 4.000 men short of 
 what, after a year of experience. with the war. was found to be neces- 
 sary for an army of 30 divisions. This estimate, when first submitted 
 to the (leneral Staff, was cut by them to 10,000, to include all repair 
 facilities, service of supply truck comi)anies, motor truck companies, 
 motor car comi)anies, and motorcycle companies, and on this num- 
 ber, as a basis, the Motor Tran>j)ort Sernce in France proceeded to 
 functioii. 
 
 The first order under which the Motor Transport Service was 
 definitelv formed, as part of the Quartermaster Corps, was General 
 Order 70, dated December 8, 1917. at G. H. Q., A. E. F. At this time, 
 developments in France had shown that the organization scheme wa^ 
 iiuulecjuate and also that the Tables of Organi/atioa were unsuitable, 
 5ind. to correct these conditions, a new estimate of personnel was 
 submitted to G. IT. Q. covering overhead, operation and i-epair. 
 In April, 1918, by (ieneral Order 38. War Department, AVash- 
 ington. D. C the ^lotor Transi)ort Service was created as part 
 of the Quartermaster Cori)s in the United States. This was the be- 
 ginning of the real organizaticm of the Motor Transport Corps. On 
 May 11. 1918, by General Order 74. (J. H. Q.. A. E. F.. the Motoi- 
 Transport Service was sei)aiated from the Quartermaster Corps and 
 placed under the Chief of Utilities. This was a decided step in ad- 
 vance, as it gave much more freedom to the Director of the Motor 
 Transport Service aiul enai)]ed him to exert a larger influence in 
 promoting ellicieiu-y in the corps. About this time it was decided 
 that the Motor Transport Service in Fiance should confine itself to 
 service of supply (|uestions solely and leave the operation of motor 
 vehicles belouiring to the combat elenu'uts in the hands of the. 
 
10 TENTATIVE MAXUAL OF INSTRUCTION. 
 
 Quartermaster C'()ri)s. Tlie estimate of personnel was therefore cut 
 down considerably and a cable was sent to the United States request- 
 ing the organization of a separate Motor Transport Corps, giving 
 a total of the enlisted and commissioned personnel desired for the 
 A. E. F. On July 11, 1918. General Order 114, G. H. Q., A. E. F.. 
 was issued changing the ]Motor Transport Service to the Motor 
 Transport Corps. Finally on August IT), 1918, General Order 75 was 
 issued by the War Department, Washington, D. C. This order 
 formed the Motor Transport Corps as a separate and distinct staft 
 corps and in addition to approving the project submitted by the 
 A, E. F. provided personnel for the United States, Alaska, Hawaiian 
 Islands, Philippine Islands and all other insular j)ossessions. It. 
 however, stated specifically that the Motor Transport Corps was or- 
 ganized merely for the existing emergency. As yet no legislation 
 has Ijeen passed making it a permanent l)ranch of the United State- 
 Army,^ 
 
 The Motor Transport Corps is charged with three main duties. 
 First, the supply, repair, upkeep and furnishing of supplies for all 
 motor vehicles, except tanks and tractors; second, the operation of 
 trucks, motor cars, and motorcycles on lines of comnnmication, and 
 in divisional, corps and army supply trains; third, technical sui)er- 
 vision of all motor vehicles. With this latter may be inchuled tlie 
 administration and inspection necessary for the Motor Transport 
 Corps to function properly. In other words, first is maintenance: 
 second, operation; third, administration. In order to enable the first 
 of these, maintenance, to function properly, four kinds of organiza- 
 tions are maintained : Service parks, overhaul parks, reconstruction 
 parks, and supply depots. In the service park minor repairs are 
 made. It performs repairs of a nature too extensive for company 
 mechanics but not enough so to send the vehicle to an overhaul park.- 
 
 There are three kinds of operation units, viz : motorcycle compa- 
 nies, motor transport companies, and headcjuarters motor commands. 
 The numbers composing each are shown in the Tables of Organi- 
 zation, both peace strength and w'ar strength. 
 
 The motor transport company is a combination of the old motor 
 truck company and motor car company. Xo need was found for 
 different organizations to drive cars and trucks. Provided there was 
 only enough work for one comi)any, motor truck drivers would 
 drive cars in addition to trucks, and motor-car drivers W'ould drive 
 trucks in addition to cars. Another reason is that a great deal of the 
 work was convoy work from base ports and drivers would drive 
 trucks one week and cars the next week. 
 
 In the organization and operation of the Motor Transport Corps 
 in France, every advantage was taken of the experience of the Brit- 
 ish and Frencli armies. From the former, valuable lessons w^ere 
 learned as to the discipline of drivers and the care to be given ve- 
 hicles to maintain them in an efficient and presentable condition. 
 From the French, lessons w^ere learned as to the most efficient 
 
 1 The lecturer should here refer to General Order 75, War Departmeut, 1918, and read 
 and explain same to the class. 
 
 2 The lecturer should here explain the latest tables of organization for the Motor 
 Transport Corps and the three classes of repair parks : service, overhaul, and recdu- 
 struction". 
 
FIELD OPERATIONS. 11 
 
 methods of opi'ialiiig- motor transportation in tlio field, the control of 
 motor transportation on the roads, and eeonomieal use of motor 
 vehicles. From that army, also, the ])rinci])le of i)oolin<j!: vehicles 
 was learned, a ))iinciple simple and self-evident in itself and now 
 i-esponsible foi' most extensive savin<:s and economy. It is. simply, 
 that as few vehicles as possil)le shall he assigned for specific purposes 
 or to individuals, but that in every locality and with each command, 
 all vehicles shall be pooled and assitrned to their work in a manner 
 largely similar to the ordering of a car from a commercial garage. 
 We also leai'ned from the French the capabilities of motor transpor- 
 tation in the transporting of ti"ooi)s. All are familiar with the classic 
 application of this jirinciple al the first battle of the Marne. This 
 |)rinciple has added immensely to the mobility of troops and exercises 
 an imi)ortant eti'ect on tactics and strategy. .Motor transpoi-t has 
 also shown its cai)acity for transjjorting artillery and small tanks. 
 The mobility and speed of the former being givatly increased over 
 that to be obtained by their own horses. I'he wagons and horses 
 are loaded into the trucks and a speed obtained far greater than 
 the horses themselves could jirovide. The Ficnch army also used 
 trucks for transporting their small taidvs. Although these taid\s 
 weighed 7 tons, by reinforcing and sui)porting the springs of the 
 truck, they were tran.sported on .'")-ton trucks and an unexpected mo- 
 bility given to these cumbersome and slow imi^lements. 
 
 It is believed that the foregoing will give a fair idea of the history, 
 organization, and functions of the Motor Transport Corps, but before 
 closing a few words shoidd be .said as to the importance and value of 
 its work during the wai'. To the Motor Transi)ort Corps belongs tliti 
 distinction of having had the fii-st organized units of the American 
 .Vrmy to ]>articipate in their full wai' duties on the battlefields of the 
 AN'orld V\';\v. Four provisional motor trans[)ort companies were 
 organized from American volunteei's serving with the French Army 
 on Oct. 1, 1017. at Soissons, France, and i)articipated in the operations 
 of (liemin Des Dames Oct. "28 to -JO, 1917, which culminated in the 
 battle of Fort Malmaison. It also rushed troops to the aid of the 
 British when the (Jernuins made their attack at Cambrai in the latter 
 l)art of Xo\ember, 1017. This counuand was later increased to over 
 •20 companies, or a total of nearly 1, :')()() men. and served continually 
 with the Fi'ench Army until May, 1010. when it was finally retu.rned 
 to the Ignited States for discharge. It j^articipated in 10 of the 
 nuijor oj)erati()ns of the allied armies during the year 1018. ]Man}^ 
 of its members were aAvarded the Croix de Guerre for their valiant 
 ser\ice. and the counuand was repeatedly ]-)rinsed by tlic French 
 Army for its valor and ellicieucv. 
 
 The efficiency of the Motor Tran>j)ort Corps in Finance, in spite of 
 its serious handicaps, was recognized by the connnander in chief of 
 the American Fxpedilionary Forces in his awarding to the Director 
 of the !Motor Transport Cori)s and all of his senior assistants the Dis- 
 tinguished Service Medal, in addition to making numerous individual 
 citations throughout the Corps. What General Pershing, the com- 
 mander-in-chief of the American Expeditionary forces, thought of 
 the Motor Trauspoit Corps is shoAvn in the following letter: 
 
12 TENTATIVE MANUAL OF INSTRUCTION. 
 
 American Expeditionary Forces, 
 
 Office of the Commander-in-Chief, March ^, 1919. 
 Brig. Gen. Meriwether L. Walker, 
 
 Director Motor Transport Corps, A. E. F., Tours. 
 
 My Dear General Walker : At this time, when many officers and 
 enlisted men are retiirnijig home and severing their connection with 
 the American Expeditionary Forces, I am glad to take the oppor- 
 tunity of expressing to yon, and the officers and men under you, my 
 appreciation and thanks for what the Motor Transport Corps has 
 accomplished. 
 
 Wlien war was declared, motor transportation was almost non- 
 existent in the Armj^ From the outset, the Motor Transport Corps 
 had to meet the most difficult conditions, including its organization, 
 at a time when the demand for motor transportation at the front was 
 greatest; it always suffered from a deficiency of at least 70 per cent 
 in required personnel and of 50 per cent in needed material. The 
 handling of many different types of motors which had been ordered 
 and shipped to France by the various services, combined with an 
 entire inadequacy of spare parts, was another difficulty that had to 
 be overcome. 
 
 That the Motor Transport Corps was able to operate, despite these 
 handicaps, and to keep enough vehicles running at the front to supply 
 the fighting troops speaks well for the energy and perseverance of 
 your officers and men. Under all conditions of weather, on bad 
 roads, often under heavy fire, at the front, and throughout France, 
 they labored cheerfully. Your well-considered plans would have 
 soon borne fruit and resulted in a highly efficient service. 
 
 In ending I can not neglect the opportunity of thanking you per- 
 sonally for the energetic effort and enthusiasm you have displayed 
 in your difficult task and which produced such fine results. 
 
 Sincerely, yours, 
 
 John J. Pershing. 
 
FIELD OPERATIONS. 
 
 LECTURE II. 
 
 THE MOTOR TRANSPORT COMPANY. 
 
 The motor transport oonipany is iiorinally organized into three 
 sections of nine trucks, each section under connnand of an assistant 
 truckniaster. The service trucks, i. e., tank trucks, etc., are usually 
 kept under the immediate orders of the truckmaster, as they do not 
 form an integral part of the cargo sections. Wlien the company is 
 not operating in convoy, the service trucks may be assigned to cargo 
 ^vork, and in such cases should be attached to sections. 
 
 ORGANIZATION OF MOTOR TRANSPORT COMPANY. 
 
 (War strength.) 
 
 Units. 
 1st lieutenant 
 2n(l lieutenant 
 
 Total conunissioned 
 1st sei-freant 
 Sergeants 
 Corporals 
 Cooks 
 Privates 
 
 Total enlisted 
 
 Aggregate 
 Privates, 1st class 
 Cars, motor, light open, 
 
 5-passengev 
 Motorcycle with side car 
 Trucks, cargo 
 Trucks, cargo 
 Trucks, tank 
 
 Kitchen, rolling, trailniobile 
 Pistols 
 Rifles 
 
 b7- 
 
 Remarks. 
 
 1 
 
 1 
 
 2 
 
 alp 
 
 IpCr 
 
 or34 
 
 2r 
 
 er24 
 
 78 
 
 80 
 
 drlO 
 
 1 
 
 1 
 
 v27 
 
 w2 
 
 2 
 
 1 
 
 4 
 
 76 
 
 a. Truckmaster. 
 
 and 32 
 
 and 1 mes- 
 
 b. 1 clerk, 3 chiefs or sections' (assist- 
 
 ant truckmasters) ; 1 mess 
 sergeant ; 1 property sergeant ; 
 and 1 mechanic. 
 
 c. 2 assistant mechanics 
 
 drivers. 
 
 d. 9 assistant drivers 
 
 senger. 
 
 e. Assistant driver. 
 p. Armed with pistol. 
 ;•. Armed with rille. 
 V. Class A or Class B. 
 «•. 1 Truck, light repair and 
 
 for company supplies 
 
 AA). 
 Not?: : If company is partially or fully 
 equijiped with passenger 
 cars instead of truck .substi- 
 tute 2 passenger cars for 
 eacii cargo truck of Class A 
 or Class B. 
 XoTK. Class AA is J-ton truck. 
 
 Class A is li-ton truck. 
 
 Class B is 3-ton or over truck. 
 
 13 
 
 truck 
 (Class 
 
14 
 
 TENTATIVE MANUAL, OF INSTRUCTION. 
 MOTOR TRANSPORT COMPANY ORGANIZATION. 
 
 COMPANY COMMANDER. 
 
 1st Lieutenant. 
 
 Administration. 
 
 Operation. 
 
 Supply accountability. 
 
 Discipline. 
 
 2nd-Lieutenant. 
 
 Asst .to company commander. 
 
 1st Sergeant (truckmaster). 
 
 General administration and 
 
 inspection. 
 Organization and despatching 
 
 of truck convoys. 
 Organization of fatigue duties. 
 Supervision of roll calls. 
 
 MECHANIC. 
 
 Supervision of re- 
 pairs. 
 
 Mechanical inspec- 
 tion. 
 
 Preparation spare 
 parts requisitions. 
 
 COMPANY CLERIv. 
 
 Preparation and trans- 
 mission of returns. 
 
 Receipt and transmis- 
 sion of orders. 
 
 Maintenance of per- 
 manent records. 
 
 ASSISTANT 
 MECHANICS. 
 
 CHIEF OF SECTION 
 
 (Assistant Truckmaster) 
 
 Executive of his ssction 
 
 of trucks. 
 Controls: 
 ♦Operation, repair, up- 
 keep_, inspection. 
 Responsible for: 
 Discipline, instruction, 
 
 sanitation. 
 Police of quarters. 
 
 PROPERTY 
 SERGEANT. 
 
 Responsibility for all 
 unissued company 
 property. 
 
 All property records. 
 
 Procurement of all 
 company supplies 
 and spare parts. 
 
 Issue of supplies and 
 spare parts. 
 
 Drawing and issuing 
 
 of rations. 
 Supervision of cooks, 
 
 kitchen and mess. 
 
 CHIEF OF SECTION 
 (Assistant Truckmaster). 
 
 Executive of his section 
 
 oftrucks. 
 Controls: 
 ♦Operation, repair, up- 
 keep, inspection. 
 Responsible for: 
 Discipline, instruction, 
 
 sanitation. 
 Police of quarters. 
 
 CHIEF OF SECTION 
 (Assistant Truckmaster). 
 
 Executive of his section 
 
 oftrucks. 
 Controls: 
 ♦Operation, repair, up- 
 keep, inspection. 
 Responsible for: 
 Discipline, instruction 
 
 sanitation. 
 Police of quarters. 
 
 ♦Includes responsibility for drawing gasoline, oil. and grease. 
 
FIELD OPERATIONS. 15 
 
 DUTIES AND RESPONSIIUI.U IKS. 
 
 Coinixiini coiiiiiniiHlcr. — He is lespoiisildc for tlio eHicient opoi'a- 
 tion, iiiiiiiitt'iiiUK'e. iiiid discipline of his roiiipany. He must con- 
 stantly bear in mind that the vahie of hi> or<j:anization is nieasuied 
 hv the efficiency with whidi it opeiatvs. and \)\ its ahiiity to coi)e 
 with einerfrencies. 
 
 Stcoiul I'n iitciiiiiit. — Tills ollici'i- is (he diii'ct assistant of (he coni- 
 |)an\' coniinancU'r. and has such duties and responsihililies as arc 
 Ln\('n iuni l»y the company commanded. 
 
 First ser<i('<iitt. — He is the truckmaster and tlu' e\eciiti\e of the 
 c()mi)any. He sees that all oiders, rej^nlations, and other reijuire- 
 ments are pr()i)erly cariied out; that the nu'ii perform their duties 
 proi)erly : aiul reports to the company commandci' any cases of neglect 
 or \iolation of orders re(|uirin<>: disciplinary action. He sIkjuUI be 
 a man chosen mere for his adnnnistrative and executive ability and 
 his efficiency in handling men than foi- his mechanical knowledge. 
 The mechlmic may well be chosen for his ability as a mechanic, ir- 
 respective of his ability to handle men, but the first sergeant should 
 be a man of force, as his prime duty is to maintain discipline foi' the 
 efficient operation of the company. 
 
 M( chaiuc and (isnlsUad mcchinu-H. — The mechanic and assistants 
 are under the direct control of the first sergeant. The mechanic should 
 be held responsible for the necessary rejjairs made to the mec-hanica! 
 e(|ui|)ment of the comi)any. He is in charge of the repair truck, tools 
 and e<|uii)inent jiertaining thereto. He should sign for the tool ('(juip- 
 ment and issue ii to the assistant mechanics on i)roper receii)ts. He 
 should Ite held resi.>onsible for this e(iuii)nient, see that it is propei'ly 
 maintained and that any shoi'tages by dannige, loss, etc.. are prt)|)erly 
 made up. Normally, he should see that the assistant mechanics are 
 proi)erly (|ualiHed, and should instruct them in theii' work. In older 
 to perform their duties jiropcrly. the mechanic and assistant mechanics 
 -hoidd l)e thoroughly familiar with the instruction books issued by 
 the makers of the vehicles furnished to the company. 
 
 The duties of these men will be taken up further under o])erations 
 and maintenance. 
 
 Coin/xdiji clerk. — Has charge of all records. rej)orts, and corre- 
 sj)ondence of the company. He notifies members of the company as 
 to orders and instructions recei\ed, calls ui)on them for the rendering 
 of jH-escribed rejjorls, and in consideration of other incidents where 
 he nnist exercise authority, he has the rank of sergeant. Other duties 
 for him are prescribed by the c<)m])any commandei- according to 
 local conditions. 
 
 Prajxrii/ x('r(/t'(int. — Is responsibh' for all sui)plii's and e(|uipmenl 
 iiot actually issued to individuals, and keeps the necessary records 
 therefor. He is responsible, moreover, that all issues of property are 
 |)r()perly receii)ted for by the persons responsible. He keei)s the 
 property under his charge clean and in i)roper order, and sliould have 
 a list ui) to date of all property and its disposition. All dealings with 
 the (|uartei-master or supi)ly officer, not re(|uiring the personal inter- 
 \ ention <d' the comi)any connnander. should be carrie<l on by him. 
 
 Mess seigadit. — Has direct charge of the mess hall, kitchen, and 
 all nnitters pertaining thereto, including sui)ervisi()n of the cooks or 
 
16 TENTATIVE MANUAL OF INSTRUCTION. 
 
 other men working in tlie kitchen. Draws the rations, sees that they 
 are economically used, makes np bills of fare, sees that the kitchen,, 
 mess hall, and premises are clean and sanitary, and that all orders in 
 reference thereto are properly carried out. His authority to con- 
 tract debts, or expend money should be carefully watched and checked 
 by the company commander personally. In some cases, the duties of 
 mess sergeant are performed by the property sergeant, but this de- 
 pends on the special aptitude of the man, as well as on other local 
 conditions in the company. 
 
 Chiefs of sections. — Each chief of section (assistant truckmaster) 
 is responsible for the discipline, instruction, and all other matters 
 pertaining to the personnel of his section ; for the operation, repair,, 
 and upkeep of the equipment assigned thereto. He is the inter- 
 mediary between the men of his section and the truckmaster or com- 
 pany commander. His supervision extends to all the details con- 
 nected with his section, including police and sanitation of quarters* 
 seeing that his men are provided with the necessary equipment and 
 clothing. All orders for his section, either regarding the members 
 of his personnel or the units of his equipment, should be given through 
 him. He should assure himself that his section is in proper con- 
 dition at all times by making frequent and systematic inspections 
 of his men and equipment. He should examine all his vehicles on 
 their return from AA^ork, and see that the drivers have taken proper 
 care of them and that the proper repairs are made. In his absence, 
 for any cause, a suitable man should be designated to perform his 
 duties. His duties will be taken up further in lectures on field work. 
 
 Driver'. — He keeps his vehicle and its equipment clean and in 
 proper repair and working order. In order to clo this he utilizes his 
 spare time while not on duty to do the minor work required thereon. 
 He should be especially required to attend to the proper lubrication 
 of all parts and truck mechanism, and to report promptly any defect 
 noted or repair needed. In transporting material or supplies, he will 
 see that the vehicle is not overloaded, that the cargo is properly loaded 
 and lashed, and ordinarily he is responsible for its safe delivery. 
 He should be familiar with the mechanism of his vehicle and its 
 proper operation, and for this purpose he should be thoroughly 
 familiar with the contents of the instruction book issued by the 
 makers of the vehicle. He should be required to wear proper uni- 
 form when driving. His duties will be taken up further in the 
 lectures on field work. 
 
 POLICY AND ATTITUDE OF COMPANY COMMANDER. 
 
 The company commander should endeavor to standardize, in 
 Avriting if possible, all important elements of company procedure. 
 Unless all duties and functions are clean cut and clearly defined, a 
 motor transport company, owing to the nature of its work, will 
 become out of control and inefficient. 
 
 The development of company spirit, or esprit de corps, must be 
 fostered in every way possible by the company commander. No 
 one factor can be of more value in maintaining good discipline in 
 camp and on the road. The men should be neat in their personal 
 appearance and their vehicles at all times clean. Men can be led to 
 
FIELD OPERATIONS. 17 
 
 take great pride in their triicUs and in (lu'ir work. The development 
 of esprit de cori)s must nec-essarily rest very hir<ji:ely ui)on the person- 
 ality of the company connnander and the spirit which lie instills into 
 his noncommissioned officers and men. 
 
 GENERAL REGULATIONS. 
 
 The company commander should use the folh)wino- a> a <2:uide for 
 regulations which will be drawn up by him and postetl for the com- 
 pany, in addition to AVar Department, department and post or camp 
 orders : 
 
 Order forbidding introduction of intoxicating liquors. 
 
 Order against gambling. 
 
 Rules for sanitation to fit the given situation, especially as to 
 latrines. 
 
 Pecuniary responsibility of men for loss or damage to any equip- 
 ment whatsoever, which is clearly due to negligence or carelessness. 
 
 The rules of military courtesy briefly outlined. 
 
 Kstablish definitely the limits of the camp. 
 
 Impress upon the men the danger and prevalence of venereal dis- 
 ease and outline to them general orders on the subject. Post rules 
 regarding reporting for prophylactic treatment. 
 
 Post necessary fire regulations for (juarters, kitchen, and trucks 
 (j)articularly the handling of gasoline). 
 
 Establish guard rules. 
 
 Ins]>ections of (|uartcrs. kitchen, personal equipment, and vehicles 
 should l)e carefully and regularly made. Inspection under arms 
 should be held weekly, preferably on Saturdays and muster days in 
 the manner prescribed in Infantry Drill Regulations, followed by 
 an inspection of vehicles. 
 
 SUGGESTED DAILY SCHEDULE IN CAMP. 
 
 6 a. m. Reveille. 
 
 6.15 a. m. Roll call, followed by short setting-up exercise. 
 
 7 a. m. Breakfast. 
 7.30 a. m. Camp police. 
 
 8 a. m. Morning reports in, and sick call. 
 
 8 a. m. Camp inspection; formal on Saturday, informal on other 
 days. 
 
 8.15 a. m. Drill and instruction (military and technical). 
 
 9.30 a. m. Work on trucks; fatigue. 
 12 noon. Dinner. 
 
 1 p. m. Work on trucks: fatigue, and instruction (military and 
 technical). 
 
 5.30 p. m. Supper. 
 
 6 p. m. Town leave. 
 
 p. m. Taps. 
 
 THE MOTORCYCLE COMPANY. 
 
 The general scheme of organization and administration of a 
 motorcycle comi)any is identical with that of a motor transport 
 company. The details of organization are: 
 
 130647—19 2 
 
18 
 
 TENTATIVE MANUAL OF INSTRUCTION, 
 
 ORGAXIZATIOX OF ^rOTOIK'YCLK COMTAXV 
 
 (War strength.) 
 
 UNITS. 
 
 1st Lieuteiijiiit 1 
 
 2d I.ieiitenant 1 
 
 Total coiiiniissioned 2 
 
 1st Sergt'tiiit alp 
 
 Sergeants bSp 
 
 Corporal clp 
 
 Cook Ip 
 
 Privates, 1st class d30p 
 
 Total Enlisted_-__ 8S 
 
 Aggregate 40 
 
 Motorcycles with side cars 32 
 
 Trucks, cargo. Class AA w2 
 
 Pistols 40 
 
 HKMAUKS. 
 
 (t. Cycle-master. 
 
 h. 1 mess and supply sergeant, 1 me- 
 clianic. and 3 assistant cycle- 
 masters. 
 
 c. Clerk. 
 
 (1. 1 assistant uiechanic, 2 di-ivers. and 
 27 inotorcycle drivers. 
 
 l>. Armed with jjistol. 
 
 If. For comically supplies. 
 
 DUTIES AND IJESPONSIIULITIKS. 
 
 Getiend. — Tlie niotorcycles and side cars assigned to a company 
 will be tho.se of the standard makes issued to the Army. The de- 
 tails of equipment vary according- to the specific make of motor- 
 cycles, and there is no general list of equipment that covers all these 
 types. The specific list, however, will be given in the invoices or 
 other record of property furnished the company commander when 
 he receives the motorcycles assigned to his company. In addition 
 to this invoice, he should procure the printed publications issued by 
 the manufacturer of the motorcycles which ordinarily include de- 
 tailed instructions as to their care, operation, and upkeep, and a 
 parts list, giving the serial or manufacturer's number of each part. 
 
 In each company, the division of responsibility with reference to 
 operation, repair, and upkeep of the mechanical equipment should 
 be established by the company connnander, and published in a com- 
 pany order, so that each member of the company shall be thoroughly 
 familiar therewith. 
 
 The general practice is to make each motorcycle driver respon- 
 sible for the operation, care, and upkeep of his motorcycle and equip- 
 ment, as well as all other property assigned him. The extent of the 
 i-epairs that the drivers should be required to make depends much 
 upon their ability and training. In general, hoAvever, this will ex- 
 tend to what are classed as minor repairs, not requiring an extensive 
 mechanical knowledge. Work on the motor, ignition and electric 
 lighting system, or on the interior mechanism of running pans 
 should normally be done under the direct supervision and orders of 
 the mechanic. Aside from this it is better for the chief of section 
 to determine the proficiency of the individual driver before per- 
 mitting any repair, except the most simple, to be performed by him. 
 
 The motorcycles of each section are under the direct supervision 
 of the assistant cyclemaster (chief of the section), who is held re- 
 sponsible for their upkeep and repairs. Likewise, the mechanic, 
 with the assistant mechanic, has general supervision over the mech- 
 anism of the motorcycle equipment, as well as the detailed repair 
 work devolving on them. 
 
 Duties of assistant (n/clernaster. — Each assistant cyclemaster is re- 
 sponsible for the discipline, instruction, and all other matters per- 
 
riKLI) OPERATIONS. 19 
 
 taiiiing to the persoiiiu'l of h\> section; and for the operation, repair, 
 and upkeep of the eipiipnient assigned thereto. He is the inter- 
 mediary bet^veen the men of liis section and the cycleniaster or coni- 
 ])any connnander. His supervision extends to all details connected 
 with his section, including police and sanitation of quarters, seeing 
 tiiat his men are provideil with the necessary e<|uii)ment. clothing, 
 etc. All orders for his section should be given through him. He 
 should assure himself that his section is in i)ropei- condition at all 
 time;- by nudving fre(|uent and systematic inspections of his men and 
 e(|uipment. He should examine all his motorcycles on their return 
 from work, and see that the drivers have taken proper care of them, 
 and that the {)roper repairs are nu\de. In his absence, for any cause, 
 an acting chief of section .should be de.signated to perform his duties. 
 
 Ihit/(\ of the mechanic and <tJ<s/.st(f.nt nicchanlc. — The practice in 
 reference to mechanics varies in different companies ac-cording to 
 local circumstances. The two general systems are (1) the mechanic 
 and assistant mechanic are undei- the diiect control of the cycle mas- 
 ter and are not assigned to a gi\"en section: {'1) the mechanic and 
 assistant mechanic are assigned to sections, and each comes under the 
 control of the corresponding chief of section. In either ease, how- 
 ever, the mechanic should be held generally responsible that proper 
 repairs are made. He is in charge of the re})air and tool e<[uii)ment 
 pertaining to the organization. He should sign for the tool e<|uip- 
 meut and issue it to the assistanct mechanic on i)ro[)er receii>t>. He 
 should be held responsible that this equipment is properly kei)t u|), 
 aiul that any shortages by danuige, loss, etc.. are proi)erly nuule up. 
 Normally, he .shoukl see that the assistant mechanic is properly 
 ({ualitied and should instruct him in his work. In order to perform 
 proiH'rly their duties, the nu'chanic and assistant mechanic should 
 l)e thoroughly familiar with the instruction bool< issued by the 
 maker of the machines furnished the company. 
 
 I>ufi( s of driver. — He keeps his motor cycle and its e(iuipment clean 
 and in jn'oper repair and working ordei-. In ordei- to do this, he 
 utilizes his spare time while not on duty to do the minor work le- 
 (|uired thereon. He should be especially re<|uire(l to attend to the 
 j)roper lubricatum of all parts of the motor-cycle mechanism, and 
 to report promptly any defect noted or i-epair needed. ()i)erators 
 are cautioned against overloading a motor cycle or side car. The 
 maximinn weight to be carried by a solo motor cycle is 300 pounds. 
 Tlu' maxinnnn for a motor cycle and side car com!)ination is A~^() 
 pounds. These weights apply to the twin-cyliiuler, three.-si)eed 
 motor cycles now in use. The driver should be familiar with the 
 jnechanism of his nuichine and its propel- operation, and for this 
 purjxjse he should thoroughly study the contents of the instruction 
 book issued by the maker. The driver should be re<|uircd to wear 
 the proper uniform when driving. 
 
 Iioiifinc. — The following is a bi'ief account of the <lnily routine of 
 a company engaged in work at a dejjot or permanent canq). The 
 regular reveille and l)reakfa>t should be had at the hours prescribed 
 for the command in general. After reveille, the tents or (juarters 
 should be [)roi)eidy airanged. i)unk-^ made up. etc. This is followed 
 by military and technical instruction and drill iindci- the conq)any 
 officers and noncouunissionecl otlicers. 
 
20 TENTATIVE MANUAL OF INSTRUCTION. 
 
 When a machine returns to the company park, after the day's run, 
 it should be gone over by the driver, under supervision of the assist- 
 ant cycle master, and be put in shape for immediate work if ordered 
 out. This includes the filling of gasoline tanks, replenishment of 
 lubricating material, filling lamps, if they use oil, and in making all 
 repairs and adjustments. The invariable rule should be that all 
 motor cycles in the park are always ready, to make a day's run. 
 
 Motor-cycle company commanders can not be too careful of the 
 grade of oil used. Never allow a tank to be filled with automobile 
 oil unless in an emergency when motor-cycle oil can not be obtained. 
 In case auto oil has to be used, frequent use of the hand pump is 
 necessary. Motor-cycle oil for summer use should be Mobile B; 
 and in winter Mobile BB; or during extreme cold weather. Mobile 
 A or oils of like viscosity and flash test. 
 
 The issuing of gasoline and other supplies is done under the 
 innnediate supervision of the man detailed therefor. Precautions 
 to be taken against fire should be given in the form of " Fire Orders "" 
 prepared by the company commander. 
 
 On returning to the company park, the drivers turn in the written 
 order, if one was given, that sent them to work, and at the same 
 time complete their daily reports and turn them into the company 
 office. 
 
 The other routine work is carried on according to circumstances 
 that vary so greatly that more definite description thereof would be 
 without profit. 
 
 The general regulations in addition to War Department, depart- 
 ment, and post or camp orders will be followed the same as in motor 
 transport companies. 
 
FIELD OPERATIONS. 
 
 LECTURE III. 
 
 GENERAL PRINCIPLES OF CONVOY. 
 
 Two or moil' trucks o[)eranii^' together constitute a convo}'. 
 A\'hen 10 or more trucks are so used, they are divided into sections, 
 each section being in cliarge of a noncommissioned officer. 
 
 A truck comi)any is composed of 27 cargo trucks, divided into -^ 
 sections of 1) trucks each. Attached to the company is a liglit repair 
 truck, which is ])hiced as a fik^ closer at tlie end of the third section; 
 each company also has -2 tank trucks, a supply or commissary truck 
 and a kitchen trailmohile. These latter do not as a rule travel 
 with the convoy, l)ut arc disi)atclu'd to u picdctcrmincd camping or 
 refilling point. 
 
 Convoys are used to transport (ti) troops, (h) materials and sup- 
 plies. 
 
 TYl'ES OF CONVOYS. 
 
 There are three tyi)es of convoys: (1) A company or part of a 
 company. (2) Two or more companies operating together in a train. 
 (8) Group convoy, which consists of several trains operating together 
 at times amounting to several thousand trucks. This type is not 
 ordinarily used, except when large numbers of troops are to be 
 moved. Troops are usually transported in group convoys. In 
 handling group convoys the following important ])rincii)les should 
 govern. 
 
 IJKI.AIION I'D INIANTl.'Y ( (IMJA M/ ATION . 
 
 It may prove of assistance to the student to note the similarity 
 existing between his infantry training and that of his Motor Trans- 
 port work. Just as the school of the soldier is first taught in infan- 
 try work, so is the handling of a truck taught in motoi- ti'ansport 
 work. The section and handling of a section correspond to that of 
 a platoon of infant ly. Ihc truck comj^any corresponds to a com- 
 pany of infiintry and the motor transport train (two or more com- 
 panies) corresponds to a battalion. 
 
 The duties of the commanding officer are maiiy and \ aiied. I i^oii 
 him devolves the responsibility for the efficiency of the entire unit. 
 If he is lax in discipline, and inditl'erent to the care and u[)keep of 
 liis e(|nij>ment. his attitude will ]»c reflected l)y the entire command. 
 
 21 
 
22 TENTATIVE MANUAL OF INSTRUCTION. 
 
 A feAv of the duties of the comniaiuliiig officer are enumerated, in 
 order to giA'e a general idea as to what is expected of him. It is his 
 duty to choose and instruct competent noncommissioned officers to 
 assist him in his work. He must see that all of the rules and regula- 
 tions of the Army, and of the Motor Transport Corps are observed, 
 and that any man who violates these rules is properly dealt w^ith. 
 Befoi'e starting on a convoy, the commanding officer will be sure 
 that the supply of gasoline is adequate for the trip; that rations 
 and clothing for the men are sufficient; that proper road repair 
 facilities are provided, and that the cargo has been properly 
 loaded. While pre])arations are being made to leave, he should 
 devote his time to inspecting the company, observing each truck, 
 each man, and seeing that everything needed has been loaded, 
 taking into consideration the length of time they Avill be on convoy 
 and when and where they will be able to procure more supplies. 
 He will also provide himself with necessary maps, passes and orders. 
 AVhen the company is ludted. the conuiianding officer will see that the 
 drivers and assistant diixers do whatever is necessary to prepaie 
 their vehicles for an immediate start. It is of the utmost importance 
 that the men should i)repare their e(iui})ment to resume a trip at a 
 moment's notice, before they are disnussed and allowed to seek their 
 (juarters. It is a great temptation at the end of a long hard day to 
 slight this particular phase of the Avork, making the excuse that they 
 will do the necessary cleaning and refilling in the morning before 
 starting. The result of such a practice is that many things are left 
 undone. The last thing the company commander should do for the 
 day is to make an informal inspection of his equipment and see that 
 gas lines are shut otf. seats turned up, and in case of cold weather, 
 that radiators have been drained. At times the company commander 
 will find it unnecessary to accompany the convoy, as in some cases 
 the company will be split; part of the organization going to one place 
 and part of it in a diiferent direction. Under such circumstances 
 it is for him to decide which convoy is the more important, and to 
 accompany that part. He should then send his second in connuand, 
 or his truckinaster, and assistant truckmasters, with the other 
 sections. If a company is so divided that the number of assistant 
 truckmasters is not sufficient to accompany each convoy, he will, 
 appoint one of his best drivers to take charge of the remaining trucks. 
 Onh' when the comi)any is split into small convoys should the com- 
 pany commander send the company out under the truckmaster, or 
 assistants. His place is in active command, and he should l)e with 
 the company at all possible times. His })ositi()n usually is in the rear 
 of the company: he should, nevertheless, pass the convoy as often as 
 is necessary to assure himself that the column is operating properly. 
 He should be on the watch for all trucks compelled to drop out foi' 
 repairs, and give the necessary instructions regarding them. When 
 operating through unfamiliar territory he should precede his convoy. 
 On entering strange tx)wns, he should go ahead and make whatever 
 arrangeuients may l)e necessary to pass through the city, village, or 
 large town, and ac(juaint himself with road conditions, traffic rules, 
 etc., leaving instructions with his truckmaster as to where he desires 
 to have the convoy halted until he rejoins the company. When the 
 
FIKLD OPERATIONS. 23 
 
 conipanv (•oiniiiiuitlcr is trii\elin<i' in the rear ol' lii> company, tho 
 truckinastci- who is riding- in the Hrst truck of the lirst section will 
 act as ^uide. All railroad cr()ssin<j^.s and stran«;e bridj^cs should be 
 examined before the arrival of the company, antl if necessary, a man 
 should be stationed there to transmit all orders, and in case of dantjjer, 
 to halt the convoy. In the case of brid<»es, this «;uide should indicate 
 to the drivers the number of trucks to be allowed upon the brid<re at 
 one time. In case it becomes necessary to split a conxoy. it is best 
 to do so at the end of a section. The assistant truckmaster, or 
 dri\'er, actin<»: as a <;uide should be picU'ed up by the last truck in the 
 company. The commandin«r offi<<'r is responsible for all his ecjuip- 
 ment. He should therefore a\'oid a> far as possible peiinittin«^ the 
 vehicles under his command to proceed on soft •rround with conse- 
 (pient danger to the vehicles, etc. A\'hen it becomes necessary to i)itch 
 a new camp, as in the case of a \ou<x convoy, the commanding- oHicei- 
 must detei'mine the <'ampin<:- j^iound most suitable for the men. and 
 also must >elect a suitalde parkin<<; sjjace for the ti'uck>. 
 
 Ml I'lKs ()i- 'ruK 'nacKMAsiKi;. 
 
 The truckmaster holds the j)osition next in imi)ortance to the 
 connnissioned })ei'soniU'l. He is the first ser<>;eant. and is therefore 
 the innnediate executive. He disj^atches all ti'uck convoys, under 
 directions of the connnan(lin<i' officer: he attends to all calls, such as 
 fati<>:ue details, roll calls, etc. He transmits all orders and directions 
 of the commandiiiL^ officei'. and is directly responsible to him. He 
 reports to the commandin<i' otlicei- any cases of ne<ilect oi- \iolation of 
 orders r(M|uiiini;- disciplinary action. ( )n convoys he i> usually the 
 •iuide. 
 
 Dl riKS 0|- I'm: assist. VNT liaCKMASTKlt. 
 
 At all timi's the assistant truckmaster i> the chief of hi> particular 
 section. He is to his section what the (iiickmaster is to the company. 
 He is the intermediary between his men and the Hrst seryfeant. All 
 orders for the dri\ei"s should «>'o through the assistant truckmaster. 
 He should work with the assistant mechanic on informal iiis])ections, 
 makinof sure that his section is always in ^ood condition and icady 
 to mo\"e at any time. 
 
 Dl riF.s oK iiii; ri;oi'i:i;rY ski!(u:ant. 
 
 The property ^eriicant is responsilile for all -upplies and (Mpiip- 
 ment not actually issued to indix iduals, and will keep the necessary 
 records therefor. \\v should see that all issues of projJiMty are prop- 
 erly leceiptetl for by the jx'ison^ responsible, shouhl j<ee|) the |)roperty 
 under his char<re clean and in order, and he shoidd ha\(' the list u)) 
 to date of all company property and its disposition. .Ml dealinirs 
 •with the ({luii'termaster oi' sup]>ly oHiciM- not recjUiiinii- pei'sonal 
 supervision of the company couunandcr should be canied on bv the 
 ])i'opeity sei'<2(>ant . 
 
24 TENTATIVE MANUAL OF INSTRUCTION. 
 
 DUTIES or THE MESS SERGEANT. 
 
 The mess sergeant has direct charge of the mess, mess hall, kitchen, 
 and all matters pertaining thereto, including the supervision of the 
 €Ooks or other men working in the kitchen. He draws the rations, 
 sees that they are economically used, makes up bills of fare, sees 
 that the kitchen, mess hall and premises are kept clean and sanitary, 
 and that all orders relating thereto are properly carried out. His 
 authority to contract debts or expend money should be watched and 
 checked by the company commander personally. 
 
 DUTIES OF THE MECHANIC. 
 
 The mechanic is a sergeant and the assistant mechanics corporals. 
 The mechanic is responsible for the mechanical condition of the 
 A'ehicles of the company. It is his duty to see that the assistant 
 mechanics properly perform their work, and also to oversee all im- 
 2)ortant repairs. He receipts for the equipment of the repair truck 
 and for tools and small parts. The assistant mechanics are usually 
 assigned to different sections, but work under the direction of the 
 mechanic. On convoys he is usually the file closer. 
 
 DUTIES OF THE DRIVER. 
 
 The driver is assigned to a truck and remains with that truck, lui- 
 less transferred under orders of the commanding officer. Every 
 truck is equipped with a complete set of necessary tools, for which 
 the driver is responsible and for which he signs. This equipment is 
 subject to inspection any time, and it is the driver's duty to see that 
 eveiything for which he is responsible is ready for inspection at all 
 times. He should spend all possible time on the vehicle, keeping it in 
 first-class condition and making all minor adjustments. A great deal 
 of time may be saved by a driver if he will attend to the little details 
 of the upkeep of a truck during the time that he may be held up, 
 waiting for a load, or when the convoj'^ is delayed on the road. By 
 cleaning his truck a little at a time during these waits, he Avill find 
 that when formal inspection conies it will be very much easier for 
 him to be prepared than if he had left it until the time allowed for 
 inspection arrived. The driver is also responsible for the safe de- 
 livery of the cargo and for the manner in which his truck is loaded. 
 He will not be required to assist in loading trucks, but he should see 
 that his truck is not overloaded at any time. The assistant driver 
 works under the direction of the driver, taking orders from him and 
 assisting him in every possible way. 
 
 PARKING. 
 
 In selecting a permanent j^arking place for motor vehicles particu- 
 lar attention should be paid to the condition of the ground, the 
 drainage and the amount of available space. Cinders or crushed 
 rock should be employed in a permanent park. In order that proper 
 alignment may be established, sighting posts may be planted at either 
 
FIELD OPERATIONS. 25 
 
 end of the line of trucks. All trucks will he alij^iied so that the cups 
 of the radiators will be in line with the ^ijrhting posts. It is the duty 
 of the assistant truckniaster to see that all trucks in his section are 
 properly ali<j:ned at all times while they are parked. 
 The followina' ai'e the usual methods of pai'kiriir. 
 
 COMPANY FRON r. 
 
 All the trucks of the company aic lined up side by siile. The 
 interval between trucks should be '2 yards; between sections -A yards. 
 This formation is i)est if the space is available. 
 
 COLUMN OF SKCTIUNS. 
 
 Trucks arranged in column of sections are spaced at "J-yard inter- 
 vals between trucks, and a distance of 7 yards between sections. 
 
 LINK OF SECTIONS. 
 
 In line of sections the trucks of each section are in column, sections 
 and corresponding trucks of sections being abreast. The interval 
 between trucks of a section is *2 yards. The interval between sections 
 is 7 yards. The statf car is 2 yards to the right of the first trnck of 
 the fir>t section, front wheel hubs in line. The supply truck, with 
 kitchen trailuiobile, is •_! yards to the left of the first truck of the 
 third section, front wheel hubs in line. Tank trnck No. 1 is 2 yards 
 to the left of the third truck of the third section, front wheel hubs in 
 line. Tank truck No. 2 is 2 yards to the left of the fourth truck of 
 the third section, front wheel hnbs in line. The repair trnck is 2 
 yards to the left of the fifth truck of the third section, front wheel 
 liiib-; in line. 
 
 DISTANCKS ANn srHKOS. 
 
 When trucks are o})erating in convoy formation, it is necessary 
 that there be certain assigned distances and speeds. There are two 
 formations for mo\ ing convoys, known as " open '" and "" closed," the 
 open formation being used on the highway- and the closed formation 
 in villages, cities, or densely popiilateil cuunti-ies of any kind. 
 
 .|.v,s( <//(((/ ilisftinr(-< for /r»(7,-.s-. 
 
 Open formation. I Closed formation. 
 Yards. J Lengths. Yards. Lcngtlis. 
 
 Bftwt-en vehicles... 
 
 Bet WWII' sections 
 
 Between companies. 
 Between trains 
 
 
 20 
 
 m 
 
 100 
 
 3I 
 
 6 
 12 1 
 
 IS 1 
 
 7 1 
 20 3 
 
 
 40 (i 
 
 
 tiO 9 
 
 
 
 t<. ." 
 
 1 vard 
 
 s and sect 
 
 ions to 20 
 
 When halted, vehicles will clo-e up 
 yards. 
 
26 
 
 TE>"TATIYE MANUAL OF INSTRUCTION. 
 Speeds to be maintained. 
 
 Trucks ("lass A A 
 
 Trucks, Class A 
 
 Trucks, Class B 
 
 Ambulances 
 
 Light delivery vehiclf s 3-4 ton capacity or less. 
 trucks. 
 
 Examples: Ford and Dcdge light 
 
 Sm 1.11 passenger \ chicles. Exampl s: Ford and Dodge touring cars, roadster, and 
 
 el 3sed cars 
 
 M toreycles without side cars 
 
 Motorcycles with side cars 
 
 He ivy passenger \ehi?les. Examples: Cadillac, Packard 
 
 In towns 
 
 (miles per 
 
 hour). 
 
 Outside 
 
 of towns 
 
 (miles per 
 
 hour). 
 
 Local speed rcgulati ins will not be exceeded. 
 
 The great fault with the average driver in convoy work' i.s the 
 tendency to overspeed, and i)articular stress slioiikl be hiid upon this 
 point. The disadvantages of oAcrspeeding are many, the two impor- 
 tant ones being the destruction of roads and e(iuii)ment and the inevi- 
 table accidents which will occur. It should be the aim of the motor 
 truck company at all times to deliver cargoes in the same good order 
 in which they were taken. In modern warfare, with the limited 
 traffic facilities, the large number of vehicles of all description^, and 
 for all sorts of purposes in use, results in congestion of the roads, 
 thereby causing delays in transportation, so that the problem of 
 delay rests more upon careful handling than ui:)on speed, lender 
 normal conditions it may be interesting to note that the average speed 
 of trucks, figured over a daily run, is 75 per cent of the governed 
 speed. The Army truck will do ])etter at ."iO per cent of the go\erned 
 speed. 
 
 .\(K'II1()|)S OF KEEI'IXC COXTACr. 
 
 When convoying on narrow, winding roads which ])ass through 
 forests or are so concealed that it is difficult to distinguish ol)iects at 
 any distance in front or rear, contact is kept as illustrated in the 
 following example : 
 
 Imagine a convoy traveling on such a road. There is a sharp 
 bend, immediately followed by a fork in the road. The itineraiy 
 has been determined in advance by the c<)m})any commaiuler and the 
 truckmaster knows on his map which road to take. It is necessary for 
 him to lead the convoy. The first truck has arrived at the foi-k in the 
 road, while the secontl truck is not yet in sight. If the first truck pro- 
 ceeds the second truck driver will have lost his pathfinder. Therefore, 
 the first truck should sIoav doAvn or halt long enough to permit the 
 second truck to come in view, and so on through the convoy. The 
 method that causes the least decrease in speed, however, is that of 
 placing a man at the fork to direct trucks of the convoy as they 
 pass. This man is designated by the truckmaster of each company,, 
 and as the last truck of the company to which that man is attached 
 passes the fork he boards it, and is succeeded as guide at the fork 
 by a man selected in turn by the truckmaster of the next company. 
 and so on. 
 
FIKIJ) OI'KnATIOXS. 27 
 
 CLASSIFICATION AND MARKING. 
 
 All motor \rliicl('> arc painlcd with the it'iiiilar itli\ c-clnil) paint. 
 'Jlie Mstcin of classification is as follows: 
 
 rasst'Ujjer cars (rej^anlless of size oi' liddy) 
 
 Llf,'lit delivery trucks (1 ton or less caiuicity) 
 
 One jiiul one-half and two ton trucks 
 
 Three and four ton trucks 
 
 Five-tun trucks, or over 
 
 .Moioi- cycles with or without side cars 
 
 -Motor anihulances (all sizes and niakes) 
 
 Tractors ( except caterpillars) 
 
 ( "ater()illars 
 
 Trailers ( carfro ) 
 
 .Ma( hine shop trucks (regardless of repair eciuipuieiit) 
 
 Kitchen trailers 
 
 < )nniihus cars 
 
 Halloon winch trucks 
 
 I >isinfectors and fire eufrines 
 
 Laboratories (dental trucks, medical laboratories, photo laboratorie> 
 
 sterilizing trucks, etc. ) -_ -- 
 
 Machine shop trailers 
 
 Tank trucks (water and gasojinel an<l sjirinklers 
 
 Type 
 
 1 
 
 Type 
 
 ■J 
 
 Tyjie 
 
 :; 
 
 Tyi)e 
 
 4 
 
 Type 
 
 ."i 
 
 Type 
 
 '» 
 
 'l\vpe 
 
 1 
 
 Type 
 
 ,v; 
 
 Type 
 
 U 
 
 Type 
 
 
 
 Type 
 
 m 
 
 Type 
 
 10 
 
 Type 
 
 211 
 
 Tyjie 
 
 :m) 
 
 Tyi)e 
 
 ."»(» 
 
 Type 
 
 (iO 
 
 Type 
 
 7(1 
 
 Type 
 
 ,S(i 
 
 SYSIKM oi- \i\i;kin(:. 
 
 'V\w identiHcatioii niinibei's for all motor vehicles will he assioned 
 by the cliief. Motor Transi)ort Corps. The identiHcation numbers 
 will be placed on both sides and on the rear of each motor vehicle, 
 the symbols composino- such numbers to be 4 inches in heioht and 
 the complete number to be preceded by the letters "I. S. A."" On 
 the truck and ambulances the numl;ers will be phu-ed on the hoods. 
 On passeno;er Ciirs on the reai' door paiuds. atul on icar of tonneau : 
 on trucks the rear number will be -how ii on the rio-ht two-third^ or 
 two i)anels of the tail irate, and on othei- xchicles in the center of 
 the rear. The identiHcation niunber- on trailers will bi' placed on 
 both sides and in the i-enter of the reai' of the body in symbols not 
 less than 2 inches in height. 
 
 Xiunbers foi- motor cycles to which side cars are attached on the 
 riofht side will be placed on the left side of the oasoline tank of the 
 motorcy( le and en the rijjht side, front, and rear of the side car. 
 Symbols on motor cycles and side cars will not be less than -2 inches 
 in liei<rht. Side cars are not given sei)arate numbers. I»ut take tlie 
 number of the mot/ir cycle to which thoy are attached. 
 
 The identification numbers for motor cycles without side cars w ill 
 be shown on both sides of the gasoline tank, and on the plate attached 
 to the rear mini guard, in symbols not less than '2 inches in height. 
 
 On trucks, passenger vehicles, and motor ambidances assigned to 
 annnunition. engineer, supply, and sanitarv trains, the identification 
 insignia will be shown on both sides of Ixxlies of vehicles, and in 
 the case of trucks on the left one-third or jiatud of the tail gate. 
 
 SVSIKM or MMUKi;] N(.. 
 
 The first numei'al rf an identifying numbei- on a motor xchicle 
 will indicate the tyjx' of -uch M'hicle. This numeral, togethei' with 
 tho>e making up the (nmplelc niuiiber. oixcs the regist I'at ion num- 
 
:28 
 
 TENTATIVE MANUAL. OF INSTRUCTION. 
 
 Illllllll 
 
 JH 
 
 Both Sides Hood 
 
 nil 
 
 Both Sides Hood s. Cover 
 
 M 
 
 J2L 
 
 o 
 
 Rear End 
 
 r 
 
 o 
 
 o 
 
 y 
 
 Bottom Tail Gate 
 
 O 
 
 Both Sides of Hood 
 
 U.SA. 721 ^^ 
 
 o 
 
 Top Above Curtain 
 
 nn 
 
 o 
 
 BcfTH Sides Radiators Band 
 
 B<mt Sides Body or Superstructure Rear End Chassis 
 
FIELD OPERATIONS. 
 
 29 
 
 Rear Doors on Both Sides 
 
 Doors Both Sides 
 
 o 
 
 Rear End 
 
 '( USA 621 J 
 
 Both Sides Gas Tank 
 
 
 On Motor Cycle 
 
 C-3 
 
 With Side Car 
 
 USA 02.45 
 
 Trailer Side 
 
'30 TENTATIVE MANUAL OF INSTRUCTION, 
 
 her of the veliiclo. Thus, the six hundred and eighty-fifth passenger 
 oar phu-ed in service wouhl be type 1-085 or U. S. A. 1685. 
 
 A motor vehicle privately owned but ()[)erating in the Government 
 service has the usual identification nundjers followed by an X. 
 
 P'urther examples are as follows: 
 
 Yeliicle No. 1, passenger car U.S.A. 11 
 
 Vt'liicle No. 1. Uiiht delivery truck , U.S.A. 21 
 
 Vehicle No. 1, U-Um truck U.S.A. 31 
 
 Vehicle No. 1, Ivitclieu trailer ____U. S. A. 101 
 
 Vehicle No. .">. jirivately owned pas.^eiifier car U.S.A. 15X 
 
 Vehicle No. (5, privately owned lA-ton truck U. S. A. 36X 
 
 Vehicle No. 1. iirivately owned kitchen trailer U. S. A. lOlX 
 
 ADDniOX.VL MARKING. 
 
 In order that the identification number of each motor vehicle may 
 be indelibly shown thei-eon. such number shall be painted on the 
 right-hand longitudinal member of the frame of the chassis, together 
 with the serial number of each vehicle. These numbers shall be not 
 less than one-half inch in height. 
 
 The identification number, once assigned to a motor vehicle, re- 
 mains with that vehicle during its life, notwithstanding the fact 
 that the motor, or other parts, may be changed. When a vehicle 
 loses its identity through capture, salvage, or other cause the num- 
 l)er so vacated will not be reassigned to anv other \t'hicle. 
 
 Motor truck covers will l)e marked with the same identification 
 number as tlie trucks to which they belong. Such numbers will be 
 placed on the covers so as to make them visible on either side when 
 the cover is in place; symbols to be not less than 4 inches in height. 
 
 SECTION MARKINGS. 
 
 In order to indicate the last truck of a section a red disc 12 inches 
 in diameter, mounted on a suitable staff, is attached to the rear of the 
 truck, so as to project to the left and be visible from front and rear. 
 The end of the company, or the last truck at the end of the third 
 section, is designated by a double disk in the same way. 
 
FIKIJ) OPKIIATIONS. 
 
 31 
 
 I)i>i!k used to cU'signate end of sections. Doulile disk of the same stvle is used at the end 
 
 of companies. 
 
FIELD OPERATIONS. 
 
 LECTURE IV. 
 
 CARE OF EQUIPMENT. 
 
 1. Since the entire transportation problem depends upon the con- 
 dition of the motor equipment, too mucli stress can not be laid upon 
 the prime importance of kc'ej)iiio; this in the best possible shape by 
 means of careful attention and frequent inspections. The difficulty 
 of securing: replacement parts when the Army is operating on for- 
 eign soil, should serve as a further incentive to the individual driver 
 to conserve the wear and tear on his truck to the best of his a))ility- 
 
 DAILY nUTIES. 
 
 Each day the following duties will be performed: 
 
 1. Wash truck. 
 
 2. Fill crank case to proper level. 
 
 3. Oil fan bearing. 
 
 4. Grease water pump (use heavy grease). 
 
 5. Lubricate starting crank. 
 
 6. Grease steering connections. 
 
 7. Grease steering knuckles. 
 
 8. Lubricate clutch-bearing trunnion. 
 
 9. Lubricate clutch-case l)earing. 
 
 10. Lubricate spring shackles. 
 
 11. Lubricate rear-axle brake shaft. 
 
 12. Lubricate brake-shoe equalizer pins. 
 Every 300 to 400 miles : 
 
 1. Drain oil from crank case, wash out with kerosene, and 
 
 refill to proper level. 
 
 2. Clean motor and pan under motor, clean spark plugSi. 
 
 clean carbureter. 
 
 3. Fill uj) all grease cups and oil wells and see that oil or 
 
 grease has clear passage to bearing surface and pas- 
 sages are not plugged up with grit or dirt. 
 
 4. Clean oil strainers, 
 
 r>. Grease Avheel bearings on all four wheels. 
 
 6. Grease steering-gear case. 
 
 7. Oil spark throttle-rod sockets and joints. 
 
 8. Oil brake-rod clevises. 
 
 9. Lubricate equalizer and intermediate brake bars. 
 
 10. Examine clutch and if leather-faced cone clutch apply 
 neats'-foot oil. 
 
 130647—19 3 33 
 
34 
 
 TENTATIVE MANUAL OF INSTRTICTION. 
 
 Part. 
 
 Fan hub hearing 
 
 Pump shaft grease cups 
 
 Steering gear case oiler 
 
 Steering gear case grease cup 
 
 Steering wheel oil hole 
 
 Steering cnlumn 
 
 Spark and throttle shafts , 
 
 i'onUol l)ra<'ket bearings 
 
 Transmission case , 
 
 Brake iJull rods and connections. . . 
 
 I'edal fulcrum pin , 
 
 Brake cross rod grease cups 
 
 Torque rod grease cups, front and 
 rear. 
 
 Brake shafts on rear wheels 
 
 Hear spring perch grease cups 
 
 Magneto bearings (3 oil holes) 
 
 Dynamo drive shaft universal joints. 
 
 Quant iiy. 
 
 Few drops 
 
 Two complete turns 
 
 Fill 
 
 Two complete turns ;... 
 
 S or 10 drops 
 
 10 or 15 drops 
 
 Few drops T 
 
 Thoroughly 
 
 Enough to cover lower shaft. 
 
 Thoroughly 
 
 do...." 
 
 Two complete turns 
 
 do 
 
 Thoroughly 
 
 Two complete turns 
 3 or 4 drops 
 
 Fill one-half full. 
 
 Lubricant. 
 
 Motor oil. 
 Cup grease. 
 Motor oil. 
 Cup grease. 
 Motor oil. 
 
 Do. 
 
 Do. 
 
 Do. 
 Transmission grease. 
 Motor oil. 
 
 Do. 
 Cup grease. 
 
 Do. 
 
 Motor oil. 
 Cup grease. 
 High grade 
 
 chine oil. 
 Cup grease. 
 
 light ma- 
 
 11. Examine brakes and adjust as may be required. 
 
 12. Examine all wiring to see that connections and insulation 
 
 are in good condition. 
 
 13. Go over all nuts and bolts and tighten them if they are 
 
 loose. 
 
 14. Lubricate universal joints. 
 Every 1,000 to 1,200 miles: 
 
 1. Fill transmission to proper level. 
 2. 'Fill differential to proper level. 
 
 3. Examine all grease boots, clean, and refill. 
 
 4. Jack up vehicle and clean and grease springs. 
 
 5. Put about two drops of oil on magneto l)earing. 
 
 6. Put about two drops of oil in generator bearing. 
 
 7. Clean all gasoline strainers. 
 
 Crank case 
 
 Reach rod boots 
 
 Spring leaves (jack up frame and pry 
 leaves apart). 
 
 Hub caps 
 
 Universal joints 
 
 Gasoline pressure hand pumji 
 
 Differential housing 
 
 Transmission case 
 
 Quantity. 
 
 Drain off dirty oil; clean oil 
 screen at left of motor thor- 
 oughly: fill to level of top 
 try cock. ' 
 
 Pack thoroughly 
 
 Thoroughly 
 
 Pack thoroughly 
 
 liemove grease hole plug and 
 fill one-half full. 
 
 4 or 5 drops on leather 
 
 One-half full 
 
 Drain thoroughly, flush with 
 kerosene, refill to cover top 
 lower shaft; try cock. 
 
 Lubricant. 
 
 Motor oil. 
 
 Cup grease. 
 Graphite grease. 
 
 Cup grease. 
 Do. 
 
 Light machine oil. 
 Special axle compound. 
 
 Transmission grease. 
 
 INSPECTIONS. 
 
 The inspections that shoidd be held in all IVIotor Transport Corps 
 formations may be classified as (a) General, and (6) Technical. 
 The first class includes inspection of personnel, quarters, mess, sanita- 
 tion, camp bivouac (or billet) , equipment, and motor vehicles in so far 
 as relates to their cleanliness, completeness, and general upkeep, and 
 are either informal or formal. The second class includes teclmical 
 inspections of the motor vehicles and their mechanism, to determino 
 
FIKl.n UI'EIIATIONS. 35 
 
 actiuil nieclumiciil condition and ni)k('i'i): these inspections are dis- 
 cussed in Lecture X. 
 
 GEM'.lt \I, INI ()1!MA IION. 
 
 Informal inspections slioidd l>e made daily l»y nnil commanders 
 and as often as possible, by hiti;her c()nnnander>, and ^liouid'cover 
 quarters, kitchens, messes, etc.. as well as \ eludes. 
 
 Formal inspections are made by company commanders each week 
 where it is practicable to do so, and by hiiiher conunandeis on stated 
 occasions. The following method of procedure will be carefully 
 followed : 
 
 1. The trucks will be ihoiouiihly wa>hed with water, and bodies, 
 tools, boxes, etc.. will be cleaned. 
 
 •2. After washing, a solution of sal soda (two handfuls to a pail of 
 water) may l>e used for cleaning the grit and grease from the joints, 
 etc. Care inust be taken in using this sal soda solution that it does 
 not ( ouu' in contact with the Avoodwork, as it will tend to remove the 
 paint. Gasoline or kerosene may be used for the same purpose, but 
 sal soda is less expensive and should be used for economical reasons. 
 
 ;'). All grease cups should be Hlled and turned down until all the 
 black grease has disappeared, and luitil clear yellow grease shows on 
 all joints. Do not wipe this grease away, but leave it as an outside 
 coating to protect moving joints, etc. 
 
 4. Ihe mechanical part of the truck should then be cleaned in the 
 following order, working from the front of the truck to the rear: 
 
 1. P^ngine (taking out and cleaning spark plugs). 
 
 2. Dust pan. 
 
 3. Clutch. 
 
 4. Short shaft. 
 
 5. Steering gear and front axle. 
 G. Transmission. 
 
 7. Propeller shaft. 
 
 8. Frame. 
 
 9. Springs. 
 
 10. Differential. 
 
 11. Kear axle. 
 
 12. AVheels. 
 
 During this part of the cleaning sj^pcial attention should be de- 
 voted to testing bolts and nuts to see that (hey are not loose, and in 
 case any are missing, a note should be made that they be icplaced 
 immediately. 
 
 idir.MA rioN ANU ri;i;r\i;.\iioN r<ii; i nsi'K( i H'.\. 
 
 The fornuition for inspection will be either in line or i-olunm of 
 sections. Interval between vehicles, 2 yards: distance between sec- 
 tions. 14 yard<. Passenger vehicles on the right of the front line of 
 
 \ehicles. 
 
 POSITION OF " pukpAri: roi; iNspKcrK^x."' 
 
 Men will stand at "Attention,'' driver 1 foot from fender on side 
 of driver's seat and on a line with the front of the radiator: assistant 
 
36 TENTATIVE MANUAL OF INSTRUCTION. 
 
 drivers and mechanics, cooks, and other siicli personnel in a position 
 corresponding to that of the driver, but on the opposite side of the 
 truck. Assistant truckmaster 1 yard to the right of the right truck 
 of his section and 1 yard in front of the line of drivers. Truck- 
 master in line on right of flank, and 1 yard from assistant truck- 
 master. Company commander 1 yard in fjont of his vehicle. Other 
 company officers on his left. 
 
 Hoods of all automobiles and trucks will be raised to expose 
 motor. All tool boxes or other such receptacles Avill be open to shoAv 
 interior. Seat cushions will be raised to expose under side. 
 
 All tools, kits, and such truck equipment will be laid out in a 
 
 COMPANY FORMATION PREPARATORY TO INSPECTION 
 
 POSITION OF OFFICERS N.COI^AND MEN AT COMMAND 
 LPREPARE FOR INSPECTION Z-ATTENTION 
 
 COLUMN OF SECTIONS 
 
 
 
 LINE OF SECTIONS 
 
 
 o 
 
 ROAD 
 
 
 
 • 
 
 
 A -^ 
 
 
 A A A ■* O 
 
 sp"D"Tj''[r''D't]"D"'[r°cn h-zI- "I-u-dvci- t 
 
 •-COMMANDING OFFICER A-ASST. TRUCKMASTER-SERGEAMTS B-ORIVERS- CORPORALS 
 
 O-SECOND IN CX)MMANO ♦-MECHANIC- SERGEANT D-A5ST.DRiVERS-PRIVA-DES,l"CLPRIVATES 
 
 A-TRUCK MASTER-:!' SERGEANT 0-ASST. MECHANIC-CORPORAL *-SECTION DISK 
 
 T- STAFF CAR h-MOTOR CYCLE SIDE CAR »-COMPANY DISK 
 
 Q-TANK TRUCK Q -RE PAIR TRUCK H-SUPPLY TRUCK 
 
 IN "LINE OF SECTIONS" FORMATIONS, IF ROLLING KITCHEN TRAILMOBILE IS BroLLING KITCHEN TRAIIMOBILE 
 NOT ATTACHED TO SUPPLY TRUCK.TANK AND REPAIR TRUCKS WILL BE MOVED UP INTO THEIR REGULAR POSITIONS 
 NUMERALS BETWEEN VEHICLES AND SECTIONS ARE DISTANCES IN YARDS 
 
 uniform manner on the ground alongside the tool box. Lash ropes, 
 properly coiled, will be hung on front bows on either side of truck. 
 In temporary camp or on the march, articles of personal equipment 
 will be laid out uniformly on shelter half, rear of shelter half 1 yard 
 in front of radiator and in front of each individual. All articles 
 of equipment will be laid out so that stencil markings are plainly 
 visible. 
 
 Diagrams indicating a method of laying out equipment will be 
 found in this lecture. 
 
 As each vehicle is reached, the commanding officer will check off 
 its number on the list of vehicles belonging to his command or at- 
 tached thereto, in order to account for all of the vehicles for Avhich 
 he is responsible. Such other vehicles as are still part of tlie organi- 
 
FIELD OPERATIONS. 
 
 37 
 
 zation tliat are not in a serviceable condition, .should be subsequently 
 inspected at the repair shop. 
 
 The commanding otlicer will first examine tlu' inspection cliait or 
 form covering the individual Achicle for which [)ur[)ose the inspec- 
 tion report covering technical inspections will be used, and which 
 will have previously been Hlled out by tlie truckmaster or mechanic 
 during the technical inspection. The connnanding otHcer will note 
 particularly what provision has been made for the repair or cor- 
 rection of any faults or defects which nuiy have been discovered in 
 such technical inspection, in order to satisfy himself not only that 
 the exact condition of the vehicle is thoroughly known, but that 
 suitable steps have been taken to rectify any unsatisfactory condi- 
 tion. The cojnmanding ollicer will inspect the drixcrV log book 
 
 MOTOR COMMAND 
 PREPARATORY 
 
 OR TRAIN FORMATION 
 TO INSPECTION 
 
 POSmOMSOF COMMANDING OFFICER, ADJUTANT, AND COMPANY COMMANDERS 
 AT COMMAIND-1-PREPARE FOR INSPECTION -2 - ATTENTI O N 
 
 4 
 4 
 
 T • 
 
 KEY 
 
 • —MOTOR COMMAND OR TRAIN COMMANDER 
 6— MOTOR COMMAND OR TRAIN ADJUTANT 
 
 • -COMPANY COMMANDER 
 
 |-MOTOR COMMAND OR TRAIN STAFF CARS 
 
 ■ -FILE CLOSER 
 
 NUMERALS BETWEEN COMPANlE3tf VEHICLES ARE 
 DISTANCES IN YARDS 
 
 NUMERALS ALONG EDGE OF ROAD DENOTE NUMBER OF 
 COMPANY IN MOTOR COMMAND OR TRAIN 
 
 I 
 
 to insure that proper entries have been made therein, especially in 
 regard to repair or replacement of a part "which may have been 
 made since the original issue of the vehicle. 
 
 During inspection the commanding officer will hold at "Attention" 
 only the section that he is inspecting: the othei's Avill stand at ease 
 until called to "Attention" again. 
 
 The commanding officer will re(|uire the driver to si art the engine 
 tmd Avill obser\e its ease of starting, its quietness in running, its 
 >peed control of governor with tlirottle open and sjiaik advanced, 
 and vibration due to wear in third point susjiension, or mounting. 
 The engine will then be stojiped by throwing oil' ignition switch. 
 
 Steering connections fi-om steeling Avheel to rond wh(>els will be 
 insi)(M-ted foi- proper ndjustinent. 
 
38 
 
 THNTATIVK MANUAL OF INSTRUCTIOX. 
 
 >MI 
 
 PA 
 
 NY 
 
 FOR 
 
 
 IN COLUMN ^ 
 
 
 
 *o 
 
 
 r 
 
 
 
 7. 
 
 
 
 H" 
 
 
 
 7 
 
 & 
 
 
 og. 
 
 
 
 V 
 
 
 
 7 
 
 
 
 OQ- 
 
 
 
 7 
 
 
 
 eg. 
 
 - 
 
 
 og. 
 
 
 
 7 
 
 
 
 "D" 
 
 
 
 7 
 
 
 
 eg. 
 
 
 
 7 
 
 
 
 "D" 
 
 
 
 7 
 
 
 
 IP- 
 
 
 
 20 
 
 & 
 
 
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 7 
 
 
 
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 7 
 
 
 
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 ¥ 
 
 
 
 7 
 
 
 
 "S' 
 
 
 
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 LJ 
 
 
 
 7 1 
 
 ► 
 
 MATION PREPARATORY TO INSPECTION 
 
 POSITION OF OFFICERS N.CO.MND MEN AT COMMAND: 
 1.PREPARF FOR INSPECTION 2-ATTENTION- 
 
 IN COMPANY FRONT 
 
 TD 
 
 CD 
 
 □ 
 □ 
 □ 
 
 □ 
 
 CD 
 aS 
 CD 
 
 Z'o 
 
 CD 
 iS 
 CD 
 
 4.''> 
 zS 
 
 a 
 
 CD 
 
 2S 
 CD 
 
 a 
 □ 
 
 CD 
 
 '□ 
 a 
 
 CD 
 
 2; 
 □ 
 2S 
 
 □ 
 
 2* 
 CD 
 
 25 
 
 o 
 
 □ 
 2; 
 □ 
 
 m 
 
 -KEY- 
 
 • -COMMANDING OFFICER 
 -SECOND IN COMMAND 
 A-TRUCKMASTER-iy SERGEANT 
 A-ASST.TRUCKMASTERS-SERGEANT5 
 
 ♦ -MECHANIC - SERGEANT 
 
 ♦ -ASST.MECHANIC-CORP0RALS 
 ■ -DRIVERS- CORPORALS 
 a - ASST. DRIVERS-PRIVATES,li-' CL.PRIVATES 
 
 * SECTION DISK *- COMPANY DISK 
 X STAFF CAR 1^- MOTOR CYCLE SIDE CAR 
 
 TANK TRUCK -REPAIR TRUCK ^-SUPPLY TRUCK 
 
 NUMERALS BETWEEN SECTIONS S ROLLING KITCHEN TRAILMOBILE 
 + VEHICLES ARE DISTANCES IN YARDS. ALONG EDGE OF ROAO DENOTE: 
 POSITION OF SECTION IN COMPANY. ALL DRIVERS BESIDE RIGHT FRONT 
 WHEEL HUB. ASSISTANTS BESIDE LEFT FRONT WHEEL HUB. 
 
FIELD OPERATIONS. 
 
 39 
 
 Running o^ear will bi' examined for condition and cleanliness. 
 Brakes Avill be exaniinetl and tested for adjustnient. 
 Tool kit and unit e(|uii)nient will be insi)ected for comparison with 
 authorized e(|ui|)iiieut. 
 
 I'usition of (Iriv.T and asuistaut Uriver for iuspectiou. 
 
 Tnirk ri'.Kly for inspection. 
 
 ^Miiie making- this j^'eueral inspection the coniniaudini:- ollicei' will 
 observe particularly the cleanliness of the meclianical parts of the 
 vehicle, especially at jKiints of lubrication. The lea^t accessible 
 points on the chassis will also be inspected for cleanliness, as loose- 
 
40 
 
 TENTATIVE MANUAL OF HSrSTRUCTION. 
 
 ness of bolts, rivets, and similar connections, and incipient failures 
 of brackets, frames, or othei- structural parts can be detected in the 
 process of thorougii cleaning;, which Avould otherwise pass unnoticed 
 until breakage had occurred. Cleanliness is required not only for 
 the sake of appearance, but also to discover what is underneath the 
 dirt. 
 
 Inspections of vehicles at repair shops or other localities where 
 placed for repair Avill not follow a specified routine, but inspection 
 will be conducted to determine whether the necessity for repair has 
 been clue to improper operation, lack of cleanliness and lubrication, 
 
 9>y u A ^\ o.p 
 
 
 08= 
 
 H 
 
 e>= 
 
 
 '='^ 
 
 
 C^==Q 
 
 Skfcf 
 
 Layout of tools for inspection. 
 
 or failure to umintain proper adjustments. This inspection will 
 also disclose whether the necessity for repair has been anticipated 
 by the responsible officer in charge of the operation of the vehicles, 
 and the repair organization advised in advance as to work which 
 will be required by it on specified vehicles in order that said organi- 
 zation may plan its work accordingly, requisitioning spare parts if 
 necessary, or providing for repairs not requiring replacement. The 
 expert technical knoAvledge and experience of the officer in charge 
 of a repair organization should be utilized in connection with 
 vehicles developing trouble before the failures have occurred in 
 service. 
 
 Upon completion of the inspection specified in the foregoing para- 
 graphs, the commanding officer will initiate such procedure as may 
 
FIELD OPERATIONS. 41 
 
 be necessary lo iiisiiic the inaintenance of the higliest possible pei- 
 •centage of his e<iuipnient in serviceable operating condition. 
 
 If a technical inspection is made at this time, it should be in 
 conformity to the procedure outlined. Ordinarily, the technical 
 inspection should not be made at the same time as the general inspec- 
 tion on account of the length of time needed to make a detailed 
 technical inspection, and because of the fact that to interpret most 
 intelligently the mechanical condition of a machine, it should 
 be inspected >vhen it is more or less dirty, so as to show up ilefects 
 brought out in contrast by a slight coat of dust. After the vehicles 
 and eciuipinent are inspected, ihe cauij), ((uarters, and kitchens should 
 be inspecteil in conformity with the i)roce(hire laid down in vaiious 
 regulations and orilers on that subject. 
 
 In general the driver is personally resi)on>il)li' for the cleanliness 
 and condition of the following parts of his truck : 
 
 1. Engine. 
 
 •2. Cooling system. 
 
 ;>. Carburetor. 
 
 4. Ignition. 
 
 5. Generator. 
 
 (■>. Dash instruments. 
 7. Engine controls. 
 The assistant dri^"er is personally responsible for the cleanliness 
 and con<lition of: 
 1. Clutch. 
 •2. Transmission. 
 ■^K Drive shafts. 
 4. Rear axle. 
 ."). Rear springs. 
 0. Brake mechanism. 
 
 7. Rear wheels. 
 
 8. Front axle. 
 
 9. Front springs. 
 
 10. Front wheels. 
 
 11. Hood. 
 
 12. Fender. 
 
 13. Body. 
 
 PERSONAL CAI;E OF TIRKS. 
 
 (a) Most tire troubles are the result of abu>e rather than use. 
 
 {b) Cut off all loose ends and remove any stones or glass imbedded 
 in tires. In case of dual tires remove stones fi'om betAveen the 
 treads. 
 
 ((■) Start and stop the vehicle e-radually. 
 
 {(/) Do not turn the steeling wheel when the truck is stationary. 
 
 (<■) Keep the tires free from grease and oil. and avoid ruts, run- 
 ning in car tracks, and sharp stones in the road. 
 
 (/) .\void overloading and ovcrspee<ling. 
 
 (g) Avoid loose lumber or boxes, as they may contain nails or 
 wire that would tear the tires. (Xote. — Before cutting rubber 
 moisten it and it will cut much more smoothly.) 
 
 (h) Do not run over paper bags, or packages, as they may contain 
 irlass bottles. 
 
42 TENTATIVE MANUAL OF INSTRUCTION. 
 
 (iAsoLixK :NrrsT be handled with care and common sense. 
 
 The following precautions in regard to fire should be heeded: 
 (lasoline va})orizes easily, and as the vapor is heavier than air it 
 sinks to the ground. AVhen tilling the gasoline tank, be sure that 
 there are no open lights or fire near. If the tank is to be filled at 
 night, do not use a flame lamp. Use an electric flash lamp. Do nrt 
 use the gasoline funnel for anything but gasoline. 
 
 IN case of fire do not TRY TO PUT IT OUT AVITII AVATER. 
 
 The burning gasoline will float and spread tlie fire. Always keep a 
 pail or two of sand hand}', and smother the flame with it. A fire 
 extinguisher should also be kept at hand. 
 
 In case of a truck catching on fire, the first thing to do, if possible, 
 is to turn off the supply cock from the tank to the carburetor, push 
 the car away from the blazing gasoline on the ground, then cover the 
 flame with sand or dirt, if a fire extinguisher is not available. 
 
 Do not flood the carburetor and let a pool of gasoline collect under 
 it when priming, as a chance short circuit ma}' give a spark that will 
 set it on fire. 
 
 Keep all engine parts, drip pans, and under parts of vehicles clean 
 and the gasoline that drips into these parts will .soon evaporate, 
 thereby greatly reducing the possibility of fire. 
 
 COLD WEATHER PRECAUTIONS. 
 
 Upon the approach of the winter season it becomes the duty of 
 every member of the Motor Transport Corps, and particidarly those 
 responsible for the care and upkeep of motor equipment, to see that 
 all necessary j)recautions are taken to prevent damage incident to 
 the freezing of water in radiators, cylinders, and pumps of the motor 
 transportation in their care. Experience has demonstrated the fact 
 very clearly that cold weather need have no effect on the efficient 
 operation of motor vehicles provided reasonable and necessary pre- 
 cautions are taken to prevent freezing. 
 
 Officers and men responsible will be held strictly accountable for 
 any damage due to freezing. 
 
 The following instructions are for the information and guidance 
 of all. 
 
 A¥hen freezing w^eather is anticipated, the responsible officer Avill 
 see that the following precautionary measures against freezing are 
 taken : 
 
 ANTIFREEZING MIXTURES. 
 
 The antifreezing mixture to be issued will be the best obtainable. 
 The strictest economy will be observed, using this mixture only Avhen 
 absolutely necessaryj and in the quantities and for the class of cars 
 prescribed. 
 
 It will be necessary to limit the use of this fluid, generally speak- 
 ing, to staff cars. Experience shows that a calcium chloride prepara- 
 tion has a corrosive tendency, and is destructive to rubber hose, pack- 
 ings, and electric insulations upon which it has dripped or spattered. 
 
KIKIJ) OPERATIONS. 
 
 43 
 
 (//) This corrosion is due to tlic solution ln'iiiii- used without 
 ])roi)('r dilution or cist' iin[)uiv clu'niicMls. When directions arc fol- 
 lowed, no serious trouble will result. J'he [)ractiv-e of addinn; too 
 much of this solution must be guariled ajiainst. 
 
 (A) In some cases the solution is inett*ecti\e because of the con- 
 stant renewal of water witliout nuiintaininji a full >tren<!:th mixture. 
 
 {(■) In u>in<j: any antifreezin<i- mixtuiv. it i- ('--xMitial to follow 
 exactly the insti'uctions furnished therewitii. 
 
 Xdii 1 1( I :iii</ sfiliil inn for ni(l\(i1<irs { ih init ii n il nholtnl (iinl iratrr). 
 
 
 Freezing point . 
 
 * Volume. 
 
 Per cent. 
 .'> 
 
 15 
 
 25 
 
 (Iravily. 
 
 F. 
 
 
 99 
 
 20° 
 
 
 9« 
 
 10° 
 
 97 
 
 0° 
 
 
 .30 
 
 96 
 
 -10° 
 
 
 .35 
 
 96 
 
 -30° 
 
 
 40 
 
 95} 
 
 -:J0' 
 
 
 4(i 
 
 94 
 
 -40° 
 
 
 
 92 
 
 -50° 
 
 
 (a 
 
 91 
 
 
 
 
 (iravity tests of (he coolin<2- solution >hould be taken at least three 
 times each week, and the correct projjortion maintained at all times. 
 If the i)roi)ortion of alcohol falls below specilications, the eno;ine 
 will be in danger of freezinfr. Should the engine boil from any 
 cause while a solution is employed, a rapid loss of alcohol will re- 
 sult and the correct proportion shcadd be inmiediately obtained to 
 avoid later freezinjr. 
 
 In thi^ (|iie>tion of care and upkeep d" luotoi' e(|uipnK'ul the per- 
 sonal element enter^ to a hiliie I'Xtent. 
 
 xv M(;irr — wiii.x i;.\ni \ ici; < \x \\v. nit\iM:n. 
 
 (^0 The vehicle should be tilted or inclined so that the water will 
 How toward the drain cocks and not form pocket-. 
 
 (A) The radiators. i)umps, and carburetors of all inotoi- vehicles 
 will be drained by openin<z" the drain cccks at the lowest point in 
 the circulatin<L!: system. 
 
 (<■) As a further a>suraiice thai no water remain- in the .system, 
 the entriue wiil be started and lun slowly foi- a few minutes. Shut 
 ort' the wasoline supi>ly at the tank, thu- allowinu- the eufriue to 
 "die," when the remainino; aasoline in the carburetor and line ha> 
 been used. 
 
 ((J) After the engine has >toi»[)e(l. carliuretor should lie drained, 
 as very often a few drops of water will ha\"e collected at the bottom. 
 T'his proc-edure will eU'ectually empty e\ery i)aiticle of water from 
 the enjrine and evaporate any remainina' moi-ture around the cylin- 
 ders, pump, and radiator. 
 
 ((') If the radiator is hot. do not replace filU'r cap tiirhtly. One 
 or two turns will answer, as very often the metal contracts, thus 
 makinii' removal ditlicult in the mornin<r. When caps are hinped or 
 clamped, do not entirely close them. 
 
44 TENTATIVE MANUAL OF INSTRUCTION. 
 
 AT NIGHT AVIIEN RADIATOR CAN NOT BE DRAINED. 
 
 (a) Heaters will be used under the hood to prevent the water 
 from freezing. Side lamps ma,y be used, if special heaters are not 
 available. 
 
 (5) If antifreezing mixture can not be obtained, motors should 
 be kept warm by running for a fev,' minutes, say every two hours or 
 oftener, according to temperature. Even when antifreezing mix- 
 ture is available, intermittent running is desirable to insure facility 
 of starting, b}' keeping water reasonably warm. 
 
 IN DAFTIME VEHICLE STANDING STILE. 
 
 Hood should be covered. Burlap bags filled with straw^ or dry 
 leaves will serve for this purpose when better means are not available. 
 
 IN DAYTIME VEHICLE RUNNING. 
 
 In zero weather water will freeze in the radiator even when the 
 engine is running. Steps must therefore be taken to provide suitable 
 aprons of canvas or other material to cover the radiators. If radi- 
 ator and hood covers can not be obtained in sufficient number, suit- 
 able covers will be improvised from material at hand. 
 
 RELEASING BRAKES. 
 
 Do not leave vehicles over night with the hand brake set. This 
 practice often results in bands freezing to the brake drums. If hand 
 brakes are not set, blocking must be used. 
 
 STARTING MOTORS IN COLD WEATHER. 
 
 {(') If radiator is frozen, do not attempt to thaw it out by nmning 
 the engine — use hot watei'. 
 
 {h) A vei*}' cold engine is difficult tt) start because the oil congeals 
 in the cylinder walls and in the bearings. If it can not be turned 
 with moderately strong pressure on the crank, the water pump is 
 probably frozen. Thaw it out by pouring hot water over it before 
 exerting too mucli force on the crank. If this is not done the coup- 
 ling will be slieared or the propeller broken loose from the shaft. 
 If the cooling system has been drained and hot water can be obtained 
 for refilling, cranking will be easier. The consequent warming of 
 cylinder walls will assist in the vaporization of the gas and make 
 the engine start quicker. Warming the intake manifold, flooding the 
 carbin-etor, and pouring a small quantity of gasoline into the cylin- 
 ders through the priming cocks are all helpful in getting a cold 
 engine started. Take care not to flood the engine with gasoline. 
 The engine runs best and works most efficiently when operating at 
 approximately the same tempei-ature as in sunnner weather. Part 
 of the draft through the radiator may be cut off by keeping the 
 radiator partially covered, and in very cold weather it may be 
 advisable to remove fan belt also. 
 
 (e) A hose attached to the end of the muffler of a running engine 
 Avill be of advantage in thawing frozen parts or warming cold parts 
 of other cars. 
 
FIELD OPERATIONS. 4a 
 
 DlilMNG ON ICi' OK FHO/.KN I!OAUS. 
 
 (a) If the Avlieol.s are "frozen in"" deeply, loosen tlieni up with 
 a jack before attempting to start the trucU. oi- severe strain will b.^ 
 thrown upon all of the driving mechanism. Take care not to injure 
 tires. 
 
 {b) W'lwn necessarv to use chains, put a fonipU'te set on both 
 wheels. One or two chains will make the truck jeik forward, thus 
 straining the entire driving luechanisui. 
 
 i)Ki\'iX(i ON Mi'DD^ OK s^()^^ V i;oAi)S. 
 
 [a) On extremely muddy roads, where the mud is st'\c'ral 
 inches deep, it Avill be necessarv to use chains continuously'. This 
 precaution will aid traction and tend to prevent skidding. If the 
 ruts in the road are extremely severe, it will be necessaiy to have 
 chains on the front wheels. Such precaution is necessary only on 
 roads of a "clayey"" nature. In the event that the dri\er has not taken 
 the precautions of a[)plying the chains, and finds himself in a position 
 where he can not gi>t traction, he nuist not spin the rear wheels, as 
 "spinning"' wheels only dig in deeper, besides oftentimes cutting the 
 tire badly by running it against a rock bedded in the ground. 
 
 (h) AYhen there is considerable snow on the ground, siuiilar dif- 
 ficulty in traction will be experienced, and chains should always be 
 used under these conditions. If chains are not available, pieces of 
 rope or twisted canvas tied through the spokes will serve the pur- 
 pose for traction temporarily. 
 
 (c) In cases where the driving must be done in snow or sleet 
 storms, or on wet pavements, all drivers are warned against speed; 
 but they are warned further not to allow the truck to lose its momen- 
 tuui. inasnnu'h as starting under these conditions will prove dillicult^ 
 
FIELD 01»ERATI0NS. 
 
 LECTl'KE y. 
 SIGNALS AND ROAU Rl LES. 
 
 In ;iivin«>' sitriinls tlu' instnictoi' should lake i):iilii-iil:ir cure to sl'o 
 iliJil ^i;i•nills iiic iwcciitc'd iti a iinifoiiii maiuu'r. and that no dcx ia- 
 tioiH iirc allowed I'roni flic nictliods and nin\ (■ni('nt> prcscrihcd. 
 
 Cum III! Siiiiiiilx. 
 I I'M- TnukiiiMsli T. ATM— Assi.stiiiU TiiKkniasi' 
 
 AI' Assisliiiil Diiv« T. I 
 
 
 sisnwls. 
 
 GIvoii 
 
 by 
 
 -:..: 
 
 :sis. .. 
 
 Ilond or arrasia;n;il. 
 
 1 
 
 Altciiliini 
 
 TM 
 \TNr 
 
 Sovonil .s!i(irt M 
 
 .\rm held ve-licM. hiind 
 
 
 
 moved ciiilcHy from side 
 
 
 
 
 
 
 to side. 
 
 '-' 
 
 Crank motors. . . . 
 
 \T.vr 
 
 2 Ions 1 list V 
 
 
 Circles described in front of 
 body with ri-jhl arm. 
 
 :! 
 
 Hoiidy to start 
 
 AH 
 
 \T.\r 
 
 None 
 
 
 Arm extended at an angle 
 (if !.■> degrees. 
 
 1 
 
 Korwiird 
 
 TM 
 
 ATM 
 
 1 Ion.,' 1 1 -1 
 
 
 \iin lowered in direction nf 
 
 liiitrie. 
 
 -■> 
 
 Spoo 1 up 
 
 TM 
 ATM 
 
 None . 
 
 
 \rni moveil up and down 
 
 
 
 'liiicVly from shoulder. 
 
 r, 
 
 
 TM 
 
 
 
 Arm extended at an angle of 
 
 
 ■J. 
 
 \TM 
 AD 
 
 Nolle 
 
 
 I-") degrees, hand moved up 
 
 
 
 and down from wrist. 
 
 
 
 TM 
 
 
 
 .\iin extended at an angle of 
 
 ' 
 
 11; ll 
 
 ATM 
 AI) 
 
 1 Ion- 11 '.SI 
 
 
 4.") degrees. 
 
 s 
 
 St<l|> Ill'lllUN 
 
 TM 
 ATM 
 
 2 shorts 1 loii'i 
 
 Ihst.. 
 
 .\nns crossed in front of body 
 and moved sharply l"o 
 sides. 
 
 it 
 
 Rc>vi">o cnnvoy 
 
 TM 
 
 Sevens 1 sliorls 
 
 and 1 
 
 -Vrm extended verticclly and 
 
 
 
 ATM 
 
 long 11 -SI. 
 
 
 circles described from the 
 shoulder. 
 
 111 
 
 Assenilili' (ti-iht or U-fl ) 
 
 TM 
 
 1 Ion?. I shi rt 
 
 and 1 
 
 .\rm extended vcrtical'.y end 
 
 
 
 \TM 
 
 Ions 1 Irsi. 
 
 
 circles descriled with han<l 
 from wrist . 
 
 ATTTtNTTON. 
 
 AVliistic .•^i^■nal: St'\A'ral ^hort i)la>(-. 
 Ann sijunal : 
 
 Kiirht hand nioxcd from w ri>( : niowd shjiri)Iy from side to side 
 altovi- the head, '^hi.■^ siirnal !.■- <riven hy the 
 tnickma-tcr and i('i)i'ati'd hv the assistant triu-k- 
 ma tcrs. who fticc toward tlu' I'car of the col- 
 niiin. ami .-^(and al "attention"' after uiviiiL^ the 
 signal. 
 
 ^^du'!l tin- siirmil i.s <»iven the as-distant drixcr 
 as^nlnes tlu* jxisition of a soldier at '• attention '" 
 jn^t hacU of the left front wjiecd liul>. cl<t-e to 
 3\ tlu> fender and fac'n<r to the front. 
 
 The tnicUmaster takes his position •_! yard-> to 
 
 the left of the front wheel hiil) id' the leadinii- 
 
 truck of the first .section. 
 
 The assistant tnickinaster of the first s'ction takes his position 1 
 
 yard to the left of the front wheel Inih of the second InicK' of hi^ 
 
 >ection. 
 
48 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 The assistant triickmasters of sections 2 and 3 take their positions 
 1 yard to the left of the front Avheel hub of the first truck of their 
 respective sections. 
 
 The mechanic takes his position 1 yard behind the assistant driver 
 of the repair truck, or file-closer, and stands at '' attention," facino- 
 to the front of the column. 
 
 Crank motor with left hand. 
 
 The assistant mechanics take their positions 1 yard behind the 
 assistant drivers of the last trucks in the first and second sections, 
 and stand at "attention," facing to the front of the c olunni. 
 
 CRANK MOTORS. 
 
 In cranking motors, the instructor should insist that the left hand 
 be used as illustrated in sketch. 
 
FIELD OPERATIONS. 
 
 49 
 
 Crank motors. 
 
 Where necessary to use two hands, the operator should place the 
 left hand in front of the right, taking care to step far enough away 
 from the truck to avoid injury, in case of back fire. 
 
 Whistle signal : Two long blasts. 
 
 Arm Signal : Circles described in front of body with right aim in a 
 clockwise direction, given by the truckmaster, repeated l)y assistant 
 truckmasters. 
 
 Driver turns on switch. Assistant driver steps to front of truck 
 and cranks motor with left hand. When motor starts, the assistant 
 driver stands with one foot on the left running board and the other 
 in the cab. facing toward the front of the column; 
 the diiver disengagi's the clutch and places the 
 gear ■-hi ft in lirst speed, l^pon completion of this 
 operiition. the assistant driver raises his left aim 
 4.') degrees from the vertical as signal to assistant 
 ti'iickmaster tliat the truck is ready to mo\e. 
 
 The chief mechanic and his assistant tiien take 
 their places on the seats of their respective trucks. 
 
 When the assistant truckmaster of the third sec- 
 tioii observes by the signals that all of the trucks 
 in his section are- ready to move lie does an about 
 face and ])asses the " ready " signal to the assistant 
 truckmaster of the second section, who in turn observes if all his 
 trucks are ready and who then does an about face and passes the 
 signals to the assistant truckmaster of the first section, who repeats 
 the movements as described above. 
 
 In giving the signals on a winding road, if the truckmaster is 
 unable to see the signal of the assistant truckmaster of the third sec- 
 tion, the assistant truckmaster of the second section will raise both 
 ai'ms to the '* Keady "' position to indicate that both 
 the second and third sections are ready to move. 
 
 FORWARD. 
 
 "Whistle signal: One long blast. 
 Aim signal: Right arm raised over head and 
 * lowered to horizontal position in front of bod}'. 
 '}d 'iliis signal is given by the company commander 
 and rei)eated by the truckmaster and assistant 
 truckmasters who face toward the front of the 
 column. 
 
 Drivers engage clutch and vehicles start. Truck- 
 master will giM' signal to start after each assistant 
 truckmaster has given the signal of readiness by raising his left arm 
 as shown in illustration. Should a motor fail to start, the convoy 
 will proceed. This truck will get under way and overtake the con- 
 vov as soon as Dossible. 
 
 Forward. 
 
 SPEED UP. 
 
 Whistle signal : Xone. 
 
 Arm signal: Carry the hand to the .shoulder; rapidly thrust tlie 
 hand upward the full extent of tlie aim several timos. 
 
 130647—19 4 
 
50 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 This ,si<>nal is <iiven by the tnickniaster and carried on by the 
 assistant truckinasters. 
 
 SLOW DO"\VN. 
 
 Wliistle signal : None. 
 
 Arm sii>nal : Arm extended upward and to the side at angle of 45 
 degrees. Hand moved up and down from the wrist. Truckmaster 
 gives signal and assistant drivers pass it on. 
 
 HALT, 
 
 AMiistle signal: One long blast. 
 
 Arm signal: Arm extended upward and to the side at 45 degrees 
 angle, and held stationary. Truckmaster gives signal and assistant 
 drivers pass it on. Assistant truckmasters stand on ground, facing 
 toward the front of column, in preparation for next signal. 
 
 Speed 111). 
 
 Slow (liiwn. 
 
 Halt coiivov. 
 
 In using either the stop or slow-down signal the assistant driver 
 must make certain that the signal is properly understood by the 
 truck following him, as for example : 
 
 (a) When <lri\ing at night and stop signal has been given, the 
 assistant driver will, if necessary, get off the truck and inform the 
 driver of the truck following by verbal signals that the convoy is 
 halting. 
 
 {b) In the case of narrow seat on a wide-bodied truck, the assist- 
 ant driver will get down on the step of his truck and face the truck 
 behind if necessarv. to nuike his signals understood. 
 
 STOP :\roTORs. 
 
 Whistle signal : Two short and one long blast. 
 
 Arm signal : Arms crossed in front of body at waist and moved 
 sharply from side to side. Truckmaster gives signal and assistant 
 truckmasters pass it on to their respective sections. 
 
 REVERSE CON\OV. 
 
 Whistle signal : Several short and one long blast. 
 
 Arm signjil : Truckmaster describes large circles above head with 
 light ami. Drivers stop vehicles, throw in reverse, and back trucks 
 to the left of the road. 
 
FIELD OPKRATIUXS. 
 
 51 
 
 Fii-st >])('U(1 i^ then (.'iioraged and wliili- slowly iii(t\iii<r the wheels 
 are cramped to the ri<;ht. The triieks move around and foi-ward to 
 tlie rio;ht side of the road, takin<r ii|) the i)resciihi'd distaiuu^s. Nar- 
 row roads may necessitate consideiahje maneincrin^' to rexcrse the 
 convoy. 
 
 -> > 
 
 Stop lliolor: 
 
 IJfVCISC colivci.v. 
 
 At completion ol" this moxcmeiit the conxov will be in a reversed 
 position: service tiiicks will pull to the side of the road, permitting; 
 car<ro trucks to pass, then take their position in rear of column. 
 Convoy will proceed without further orders in new direction. 
 
 -> 
 
 > 
 
 Method of iTvi rsiim diioction ,>( tiMvcl and at tlii' satin- tiiiii' ki'ciiiiij; road on right. 
 HACK I'P— I'OlfW AIM). 
 
 A^'histle signal : None. 
 
 -Vini siirnal ; Foi'eainis raix'd \-erticaily: hands in front of and 
 
 opposite -houlders: arms moved foi'ward and backward horizontally 
 
 in direction truck is movin<i'. l*alm- 
 
 held toward truck is si<£nal to hack: 
 
 hacks of hands toward truck indicate 
 
 >5- the -JLinal I'or forwai'd moxi'ment. 
 
 =*^ If the man sionalinir hackiiiii- di- /^T^v '*C'« 
 rh^ I'ectious desires truck nioxcd to hi- /^ r^j • 
 4^*\ ri<>ht. he so indicates hy holding- hdt 
 y hand on che-t and moving lioht arm 
 sharply to the rii^ht, repeating' the 
 movement until tiiick has covei'ed the 
 necessaiy around. For a hackinji 
 nioNcnient lo (he left, the coire-^pond 
 in«2: signal is given liy lioMing right hand on chest, and mo\ ing hdt 
 arm to the left. 
 
 If, during the backing |)rocess, it is desired thai wheels be ci-amped 
 fo right or hd't. -signals are L*'i\'en with -liort. (luick motions of the 
 
 Hack II 
 
 l"iii'\\ aril. 
 
52 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 right or left uriii, according to direction desired. The speed of the 
 arm movement always indicates the rapidity with which the truck 
 movement is to be executed. 
 
 When it is necessary to back the truck, the assistant driver takes 
 position in front of truck to give the necessary signals to his driver. 
 Careless backing of a vehicle may send it into a ditch. The driver 
 should not look around while backing, but should act only on signal 
 from assistant driver. Verbal signals may be used to augment hand 
 signals, especially at night. 
 
 STOP SIGNAL. 
 
 In order to - stop the truck while backing and turning, the as- 
 sistant driver so signals by thrusting arms to the side and th^n drops 
 them down smartly. 
 
 \ 
 
 X 
 
 stop signal use when backing trucks. 
 
 Assemble. 
 
 ASSEMBLE. 
 
 Whistle signal : One long, one short, and one long blast. 
 
 Arm signal : Truckmaster takes his position at head of column 
 of trucks, on flank where assembly is to be made, and describes small 
 circles above head with right hand from wrist. 
 
 When this signal is given the assistant truckmasters assemble 
 the drivers and assistant drivers of each section in column of two's 
 at head of their sections. Assistant truckmasters of the last two 
 sections then assemble their drivers and assistants on the first section, 
 and report to the truckmaster, who then assumes command of the 
 three sections. Men are arranged in column of two's, in order of 
 trucks, drivers on the right, and assistant drivers on the left. 
 
 The assembly is for purposes of instruction or inspection; there- 
 fore, when the column has assembled, it will be faced to the right to 
 bring it in company front. 
 
 When the assembly has accomplished its purpose, and it is the de- 
 sire of the commander that the men return to their trucks, the truck- 
 master being so instructed, will command, "Sections Post!" Eacli 
 assistant truckmaster Avill face his section into column formation, 
 and march it forward until the driver and assistant driver of the 
 first truck are opposite the front hub of their truck. The assistant 
 truckmaster halts the section, and commands, "Drivers Post!" The 
 
FIELD OPERATIONS. 53 
 
 driver and assistant driver of the first truek take their positions on 
 the drivino: seat, while the reniainino: drivers and assistants arc 
 niaivhed to their respective trucks, halted, and i)osted. 
 
 The connnand, " Fall out," which permits ilrivers and assistants 
 and others of the convoy to leave their posts, is a verbal signal passed 
 down the line of trucks. " Fall in '• is not used on convoy, the signal 
 ••Attention" being employed to bring men to their posts. 
 
 ItoAl) la F.KS. 
 
 I. Drivei-s will keep trucks on tjie right liaiid side ol the i-oad at 
 all times, whether stamling or moving. 
 
 •2. In passing vehicles traveling in the >aiiie direction, thi' driver 
 will pass on the left, and sound his horn. 
 
 8. A driver will always pass an api)roacliing vciiicle on the right 
 and give it lialf the road. 
 
 ■1. Never block a road. 
 
 ;>. In passing a standing or moving convoy, a dri\-er will slow 
 (h»wn and sound his horn. 1 
 
 (■>. AVhen convoy is halted, ;iJl men must be kept off the road. 
 
 7. The convoy must be kept together. 
 
 8. Assistant driver must at all times keej) driver in touch with 
 truck innnediately beliind. in order that speed nuiy be uniform. 
 
 0. A driver will never aliandon Ids xohicle exce])t on order of his 
 commanding officer. 
 
 10. Drivers will not permit unauthori/cd persons to ride on 
 vehicles. 
 
 II. Tf any rei)airs are needed driver will re[)ort same immediately. 
 I'i. The military police on duty will bo strictly obeyed. 
 
 13. The use of the muffler cut-out is absolutely forbidden at all 
 times. 
 
 1 I. ^\■heu vehicles arc halted, motors will not be left running to 
 e.xceetl one minute under any circmnstances. 
 
 la. Ai>propi-iate signals will be given when changing direction oi- 
 stopping. 
 
 1(>. Kxamine amount of oil, ga-oline. and water after eac-h stoj). 
 
 17. Investigate and find the cause of all innisual noises. 
 
 18. Do not smoke while driving. 
 
 19. Engine is to be used as a brake when descending hills, by 
 shifting to lower gear. 
 
 '20. AVhen vehicle is stopped on a hill, put a block or stone under 
 the rear wheel. 
 
 •Jl. Koad signs and signals will be given strict attention. 
 
 •2-2. Motor vehicles will not be driven by anyone except regular 
 ilrivers or assistant drivei's assigned thereto, unless in case of 
 emergency. 
 
 •Jo. Xever use exposed ilame or oil lantern in lilliug gasoline tank 
 or working on carburetor. Use electric torch. 
 
 •24. AVhen driving in cities, towns, or villages, nevei- double a ve- 
 liicle moving in the same direction. 
 
 •2^K A slower moving convoy must never be doubled unless com- 
 mander of overtaking convoy makes certain that doubling can be 
 <^ompleted without confusion. 
 
64 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 26. Never double a halted convoy, a halted body of troops, or body 
 of troops passing in the same direction without first gaining consent 
 of the officer in charge. 
 
 27. The speed of the convoy is governed by the last truck, the dis- 
 tance is taken from the truck ahead. 
 
 28. In proceeding along unknown roads, bridges should be ex- 
 amined before the convoy is allowed to pass. In general the rule is to 
 slow down to 6 miles per hour, and to allow only one truck at a time 
 upon one span of the bridge. In case of pontoon bridges, no matter 
 how firndy they may be anchored, they invariably stretch in semi- 
 Approaches soft 
 and in. poor / 
 condition y 
 
 Only one truck on bridge at a time. 
 
 Circular form on the downstream side, in that waj^ spreading apart 
 the flooring timbers. In passing over these bridges with a convoy, it 
 is advisable to have the trucks keep to the upstream side to avoid 
 accidents. 
 
 The convoy comuiander should first secure the location of bridges 
 from his ma]) and on a[)proaching one, order his trucks to spread out. 
 This will eliminate the confusion which generally follows when a 
 line of trucks comes to a bridge suddenly and has to slow down. If 
 
 Only one truck on each span at a time. 
 
 this precaution i,s taken, the convoy will pass the bridge without 
 jamming and confusion. The first truck, after it has crossed the 
 bridge, slows down to allow the other trucks to close up. 
 
 29. If a truck is forced to leave the convoy for repairs, the driver 
 should promptly pull off to the extreme right hand side of the road. 
 In case a truck is unable to move under its ow^n power it .should be 
 towed or pushed to a position well off the road by one of the other 
 trucks. The driver will then notify the company mechanic that he 
 requires assistance. The road repairs should not be alloAved to delay 
 the mechanic for more than 20 minutes. If further work is neces- 
 
FIELD OPKRATIONS. 
 
 55 
 
 sary on the truclv, it will eitluT be towed in. oi' the nieehanic will 
 leave men to work on the triiek. with orders to rejoin the eonvoy at 
 the earlie.st possible moment. A trnek, utter ovcrtakino- tlu' halted 
 convoy, will upon seeurinjj; i)ermission from tiie ollicer in cliartje. 
 drop in behind the last truck in the section to which it belonjis. When 
 the convoy proceeds a<j:ain the truck will take its proper place in the 
 section. OHicers will not permit their trucks to run over soft jjround 
 if it can be avoided, and will instruct their drivers to keep two ti-ac- 
 tion wheels on the hard road at all times. 
 
 30. Each truck >hall carry at all times a ."iO-foot tow rope or chain. 
 
 31. In case of a lon«r convoy in which it is necessary to take a gaso- 
 line truck, this. truck should be placed imuu'diately in front of the 
 light repair truck. 
 
 Ket-p to iipstvpam si<lc and use extrenic cnr«>. 
 OKNKHAl, HULE.S. 
 
 1. No vehicle will be left by the road side unattended. In case of 
 a breakdown or other cause for delay, the driver will remain with his 
 charge until the vehicle has been icturned to its base or after relief 
 l>y competent authority, e. g.. connuanding oflicer. 
 
 '2. There is no excuse fo!" a liroken-dowu vehicle Ix'ing left in the- 
 middle of the road. 
 
 3. A guard will be placed o\er \ chicles parked for the night. 
 
 4. Motor vehicles will be driven without lights only at such tiiiiCN 
 and such places as specilied by the trallic control or road signs. 
 
 5. Drivers should employ their spare time, when trucks are being 
 loaded and mdoaded, in oiling, greasing, and cleaning theii- trucks. 
 
 <■>. (luards to regulate ti-allic and give warning of dangei'. must be 
 posted well in advance of the convoy, i. e., at railroad grade cross- 
 ings, at the intersection of main streets or roads, etc. 
 
 IKAKKK KKCIT.ATIONS. 
 
 1. Drivers will keep on the right hand side of the road at all times 
 whether moving or standing. 
 
56 TENTATIVE MANUAL OF INSTRUCTION. 
 
 2. In changin*:^ diivction or stopping", rthvays give' nppvopriate 
 hand signals. 
 
 ■^. Pay careful attention to road signs and to convoy signals. 
 
 4. Never proceed on a road in a direction opi)osite to that pre- 
 scribed for tratfic circulation. 
 
 5. Always give way promptly . to. faster moving vehicles, upon 
 signal. ■ . ' , 
 
 6. On dry dusty roads it is necessary to reduce the s})eed, in order 
 to keep down the dust. Clouds of dust attract the enemy's attention. 
 I^educing speed also reduces lial)ility to accident, especially at night. 
 
 . 7. Loaded trucks liaA'e the right of Avay over empty convoys. - 
 8. Drive slowly at night when traveling without lights. This 
 avoids accidents and trucks are less apt to be lost. 
 
 0. If driving with lights and a car or convoy approaches, dim your 
 lights. It avoids accidents due to blinding headlights. This is espe- 
 cially true when the approaching car or convoy is driving without 
 lights. In .-approaching or passing' Vehicles under such conditions 
 dim your lights at oiace.. Xot only does the light blind the men, but 
 the shadows cast are verv cohf u^ng to a man when driving in the 
 
 dark. .'■.'■.' ;r 
 
 10. Dim all lights iji towns and cities. 
 
 11. In decending a steep hill vise the engine as a brake by shifting 
 to a lower gear. ■'. ■ ' 
 
 12. Do not make unnecessaTy noise with horns or klaxons. 
 
 13. Observe the following rules for " doubling,*' i. e., passing traffic 
 moving in the same directio^i. 
 
 (d) In passing a sta'hding or moving convoy, a driver will slow 
 down and sound his horn, wlien necessary for safety. 
 
 (h) A vehicle must never double moving vehicles having similar 
 or higher speed limits. Thus atractormust not double a truck, and 
 a truck must not double a touring car, etc., unless such action is 
 agreed to by the dfiver of faster moving vehicle. ^ 
 
 (c) A vehicle must never double when goingf^around corners ^or 
 sharp curves. ^ u , > . ■■ ' ■■ 
 
 (d) Vehicles must never attempt- to double when there is a block 
 in the traffic ahead. . : . 
 
 (e) Never double in towns or villages. 
 
 (/) Never double while descending steep hills. 
 
 {f/) Never double just before reaching the top of a hill. 
 
 (A) Do not double unless the road is wide enough to allow 18 
 inches or more between vehicles. 
 
 (?) In doubling, do not make sharp angles before or after passing 
 the vehicle in front. 
 
 14. In meeting vehicles coming in opposite direction observe the 
 following rules: • 
 
 (a) A driver will always pass an approaching vehicle to the right 
 and give it half of the road. 
 
 (h) Slow down, if the approaching vehicle is throwing clouds of 
 ■dust across the road. 
 
 (c) Slow down to half speed, if the road is narrow or rough. 
 
 (fl) In case of traffic blockade or other obstacle at the point where 
 two vehicles will meet, the vehicle having the clear road ahead has the 
 I'ight of way. and the otlier vehicle nuist slow or stop if necessary. 
 
IIKLK OPKWATIONS. 57 
 
 15. At cTo>^>^i(i<nh obstTxc tlir tullowiiiu: rulos: 
 
 (a) Unless the crossidads (an he seen in eithei* direction for 75 
 yards, slow down. 
 
 {h) A vehicle tra\i'lin<i' on a main road has the right of way over 
 vehicles traveling smaller intersecting roads, nnless specific instrnc- 
 tions to the contrary are ])res rihcd hy tlie tiattic police. 
 
 10. In crossing raiJroadx : 
 
 {a) Slow down. 
 
 {h) If gates are clo>ed. do iiol start hct'ore they are open. 
 
 (c) In case the road passes under the railroad, make sure that 
 there is adeiptate clearance between the bridge and the top of the 
 vehicle. 
 
 17. //*. ludtlng, observe the following rules: 
 
 (a) Vehicles will not halt on biidges, in narrow roads, or defiles, 
 or on turns. Tlicy \\ ill iumci- halt within ."lO yards of a crossroad or 
 road fork. 
 
 (NoTK. — ^Ivxtreme necessity may make this rule inoperative.) 
 
 (6) Should a vehicle be unalde to proceed under its own power. 
 i('<|Uest should be made on tlie next one in the lear to pull forward 
 aiul give assistance. 
 
 (c) Drivers when tji^mounted will l<ee|) oil' the center and left- 
 hand >i<le of the I'oad. 
 
 1 ILK CLOSERS. 
 
 The last cai'go tinck of the comoy sh(»uld carry the tool>. r<)[K'S, 
 jacks, etc.. which are necessary to effect simple road repairs. This 
 vehicle will be in charge of the mechanic ov other experienced 
 man, who will act as file closer, and will have the assistant mechanics 
 as near him as possible, on other trucks available to act under his 
 orders. His duties are to assist any disabled \eiiicle. and to make 
 prop;*)- disposition of broken down vehicles, subject to the orders of 
 the connn inding oflici'r. The lile closer will not leave any vehicle of 
 the convoy without taking the proper measures either to repair the 
 vehicle .on the road, tow it along with the convoy, or make other 
 proper disposition subject to the decision of the convoy commander. 
 This re]>air truck should not ordinarily stoji niore than 20 minutes 
 before going ahead to rejoin the convoy, 'rhe regular light re[)air 
 truck of the conij^any. if taken along, will be placed in the convoy 
 according to the judgment of the conxoy couunande!" and will be at 
 his disj)osition and in charge of a mechanic The reai' of the conxoy 
 is usually the best phn^e for it. 
 
 \(( IDKN IS. 
 
 In ca>e of an accident, however trivial, whicji results in injiirx to 
 persons oi- property, drivers will fill in the information called for on 
 Afctor Trans|)ortation Corps I<'oini 1J4. a supply <d" which will be? 
 ke|)t on all motor vehicles, ('ounnanding otiicers will, in every casv*. 
 institute coui't-martial j)roceedings against drivers who fail to render 
 this leport immediately upon return to their oiganization. Im- 
 UH'diately upon lieing informed by means of Motor Transportation 
 Coips Foini \'1\. or by other means that an accident has occurred to 
 one (»f his vi'hicles. the companv commnmler will himself make an 
 investigation. 
 
FIELD OPERATIONS. 
 
 LKC'TUKE \'I. 
 MAP READING. 
 
 A militiiry iiia]) is a (liii\\in<i' or plot on which roads, woods. 
 >ti('aiiis. Iiills. niar.slu's. and othor objects of inilitarv iiiii)ortancc are 
 shown in their rehitive })ositit)ns hv means of conventional si<rns. 
 
 Military inaj)s ditfer from oidinary maps in miiny ways. Tliey 
 ^i\e the relative distances, elevations, depressions and directions of 
 ail objects of military importance. While an ordinary map mifjht 
 merely indicate a road, a military map would show whether the road 
 is fenced or not, as well as its width, construction, and condition. 
 
 The ci\ il maj) shows only the larjje rivers, national hijrhways, etc.. 
 while the military map shows the width and depth of rivers. Civil 
 maps ai'e used at times as they can be used as a basis for the construc- 
 tion of military toj)0<;raphical maps. Civil maps when axailatilc 
 >hould be carried on lonp convoys. 
 
 Military map reading retjuires a <»reat deal of time, study, and 
 practice. liefore a military map can be of use to a man on a convoy 
 he must be able to look at it and visualize the actual country repre- 
 sented. He nuist at first figure the distance to be traveled, then be 
 al)le to see every hill. turn. etc. lie nnist also be able to locate woods, 
 etc. For instance, if he knew that within a certain distance he would 
 be undei' shell lii'e. he imist be able to look at the map and determine 
 (juickly just wheii' shelter may be found, the distance to it, and the 
 time it will take to ^et there. Practice is mo>t impoitant in ac<|uir- 
 itJUf ability to i-ead maps. 
 
 The most essential points in niaj) reading' are: 
 
 First. To be familiar with the various siaiis and symbols used in 
 desi<rnatin<r the ditferent objects. 
 
 Second. To uiuh'rstand that each distance on the maj) i> a tixed 
 ])art of the correspond in<i" distance on the <rround. For e-\ami)le, if 
 two places are an inch apart on the map and a mile apart on the 
 <rroun(l, an inch measured anywhere else on the map would al^o l)e a 
 mile. 
 
 Third. To realize that the directions of objects on the map corre- 
 spond to their actual directions from each other on the <>:round. 
 
 Fourth. To remember that contours and hachures nnist convey 
 a clear mental ])ictuie of the "jfround actually represented. Two 
 methods of showing the foiniations of the <;roun(l are: First, by 
 means of contours: second, by means of hachures. Of the two, the 
 first method is more «j:enerally used by the Army: they recpiire more 
 timi' to make but are more accurate. The use of hachures i> confined 
 to field sketches, where the cjuestion of time i-- paramount and where 
 only appro.ximation is necessary. 
 
60 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 Contours are the lines cut on the surface of the earth by imaginary 
 horizontal planes at equal vertical intervals from each other. They 
 are numbei-ed from up, the sea level being assumed as zero. For 
 example: »ii;;i-. 
 
 In the sketch is shown a rock wMeh is surrounded by the sea at a 
 lower or higher level, depending upon tlie rise and fall of the tide. 
 If at high tide you mark the water level and continue to mark the 
 changing level at stated intervals, such as every two hours, you w^ould 
 have a series of lines and each line would represent the surface of 
 the Avater for that period, and these lines represent contour lines for 
 that particular rock. This principle extended to cover the entire 
 section of country being mapped will give contour lines for that 
 section. 
 
 Shaded urea shows surface covered at high tide. 
 
 ('/) A watershed along which the water divides, flowing away 
 from it on either side, is indicated by the higher contours bulging 
 out toward the lower, as is sliown in the sketch between the points 
 E and F. 
 
 (b) A water course, or valle3% along which rain falling on both 
 sides of it joins in one stream is indicated by the lower contours 
 bending out sharply toward the higher ones. There are several ex- 
 amples of these valleys shown on the specimen contour map. 
 
 (c) Contours of different elevations which unite and become a 
 single contour rejiresent a vertical cliff, as shown at A. 
 
 (d) Tavo contours of different elevations which cross each other 
 represent an overhanging cliff, as shown at B. 
 
 . ,{e) A closed contour lepresents either a hilltop, or a knoll, or a 
 depression, a hilltop is shown when the smallest closed contour is 
 
FIELD OPERATIONS. 
 
 61 
 
 higher than tlic iuljaci'iit coiitoiir. aiitl a (k'i)r('>>i()ii wht'ii the >inallest 
 closed contour is Iowht than (he contour next to it. (' and D aie 
 hoth knolls. 
 
 (/) A saddle, or column, is >ho\vn by two contours of greater 
 elevation on two sides of it, and two of lower elevations on the other 
 
 -Y 
 
 A — Perpendicular cliff. B- Overhanging cliff. C — IMateau. D — Knoll. C to D — Saddh'- 
 back pass. E to V — Watorslu'd. 
 
 two sides, as illustrated between the points C and i) on the sample 
 map. 
 
 If the student will tii-st examine the drainage system, as shown by 
 the courses of the streams on the map, he can readily locate all of 
 the \alleys. Knowing the \alleys. the hill^ and ridges can then 
 
 Section tlirough X — Y. 
 
 easily be placed, even without reference to the numbers on the cou- 
 tours. 
 
 A second method of representing elevations on the ground on a 
 map is by means of short lines called hachures. Where no hachnres 
 are found on a hachured map, the ground is either a hilltop or a 
 flat lowland, and the slopes are roughly indicated by the varying 
 blackness and nearness of the hachures. The darker the sectif)n the 
 steeper the slope, and the lines always run in the direction of the 
 
<62 
 
 TENTATIVE MANUAL OF INSTRUCTION, 
 
 steepest slopes of the ground. The Hues of the luichiire always 
 radiate from tlie inside of the contour coverino- the area in question. 
 (NoTK. — An excellent discussion of the use of contour lines will be 
 found on the l)ack of niai)s issued by the (leolog-ical Survey.) 
 
 ACIIOKXTS OF TlIK Sl^KFACK. . 
 
 This inchules all elevations or depressions upon the surface of the 
 oround. whcthei' natural or artificial, which might be an aid or 
 hindrance to military opei'ations. These are indicated by certain 
 con\entional signs. 
 
 On one of the following pages will be found the symbols in gen- 
 cial use bv the Armv. Thev should be studied in order to get the 
 
 1 liicliiirc lini 
 
 Contdur lini 
 
 full benetit of the map. All infoiination which is needed on a mili- 
 tary map may be grouped under the following heads: 
 
 1. Direction. 
 
 •2. Distance. 
 
 ;^. Contour, or shape, of the ground. 
 
 4. Accidents of the surface. 
 Direction is indicated on the map by the establislied symbols. The 
 general rule of map reading and map making is that the top of the 
 map is always north, unless otherwise indicated. The map maker 
 ordinarily places on his nuip an arrow or a needle, the liead of which 
 points toward the north. N., or north, as usually indicated, means 
 the true north as distinguished from the magnetic north. When 
 the compass is used, its needle points not to the true north but to the 
 magnetic north. The variation of the magnetic needle from the 
 true north is fre(|uently indicated by a second arrow, or the true 
 i:ortli line is exi)ressed in degrees, or fractions, minutes and seconds, 
 of degrees. 
 
 P^or map reading purposes, the difference between the two direc- 
 tions, as well as the reason for it and the method of its determination, 
 may be disregarded. Or, if the compass is used, the magnetic north 
 may be taken and the true north disregarded. 
 
FIELD OPERATIONS. 63 
 
 0K1J':ntatiun c»r a mai* 
 
 A-^ oidiiiiiiily iiM'd. oi'it'iitation mean-- the |)lacin<!: ot" a inap so that 
 (lircctioiis oil tlic ma)) aic paralK'l to the corroiioiidiM^' tlii'i'ctions on 
 (lie iri'oiiiul. 
 
 DISTAMK. 
 
 Distance is (.'Xprox-d on tiu- niap l»v ils >calc: that i--. the scale of 
 the inaj) is the expression of the rehition l)et\veeii distance on the 
 gi'ound and the cori-e.>pon(liii<r di>taiice on the map. 
 
 AiKiiioDs oi i;i.ri;i:si;N riNc s( ai.ks. 
 
 Tht're are three way- in which the ^cah' of the map may he repre- 
 sented : 
 
 I''ir-t: \y\ all e.\pres>ioii in word- and Hiiiii'e.-. as: 1 inch e(inals 
 I niih>. 
 
 Second: l\\ what is called the natural scale, or the represent at i\i' 
 fraction (IJ. I'\). whicli is the fraction whose numerator repii'sents 
 units of distance on the map and whose denominator represents units 
 <)\' horizontal ilistance on the <»-round, hein<': wiitten tlius: 
 
 K. |<\= __^ ,„. 1 :(i;i,;j(i(); ,,i- i is (l,S,;i(i(): all of which are 
 
 e(|ui\aK'iil expressions and are to he understood thus: That the 
 numerator is tlu' distance on the map and the denominator is the 
 horizontal distance on tlu' ground. 
 
 'I'hiid. By what is called the grai)hical srale. 'Jhis scale is a line 
 <lrawn on tlu' map. divided into e<iual parts, each division heinir 
 marUed. not with. lis actual len>:th. hut with the distance it repre- 
 sents on t he groiuul. 
 
 It *'an readily he seen that a ma[)"s scali' must hr known in oi(h'i- 
 to ha\i' a correct idea of the distance i)etween ohjects represented on 
 the map. This is essential in determinin''' len«:,th of march. ran<;"es 
 of small aims and artillery, relative lenj;lhs of inarches hy different 
 roads, etc. Therefore, if under service conditions, you should have 
 a map without a scale, or oni' exjjressed in unfamilhir units, you 
 Would Hist of all he conii)elled to construct a scale to ri'ad yards, 
 miles. (»r some other familiar unit. 
 
 With till' incri'asin<>- nuiiiher of national highways hoiuii; con- 
 structed it will he of advanta<ii' for a Motor Trans[)ort oHicer to 
 aiMiuaiut himself with the various markings used to desi«i^nate tliesi' 
 roads and to <i('t a treiu'ral idea of the direi-tion and routes tlu'V take. 
 
 Traininii' map No. 1 designates the routes of the present national 
 hiirhways and their markings. A few of the more i)roniinent ones, 
 such as the Lincoln Highway, The Dixie Highway, the Yellowstone 
 Trail, and .letfersou Highway, are marked throughout their entire 
 lengths. The remainder more or less so. 
 
 One of till' metliods proposed and ust'd to a very small extent to 
 log roads — that is, to show ui)on the map all nei-essary information 
 as to kinds of roads, width, etc., is sliown in the training map Xo. II, 
 with the hridge shei't and key. This illustrates what may i)e done in 
 this direction an<l iiiiirht he Used locallv in chart iiiir roads. The 
 
64 
 
 TENTATIVE MANUAL OF INSTRUCTIOX. 
 
 mimbers surrounded by circles refer to the bridge sheet; eacli 
 bridge is marked to show the kind of material used, width of road- 
 way, and amount of safe load. The roads are described as to width, 
 construction, and their passability at different seasons of the year. 
 
 I JUU 
 
 si 
 
 nrr/ 
 
 If I 
 
 ::^* 
 
 
 -o2d *d 
 
 ?$ ^ 
 
 0^^^ 
 
 -5 "^ 
 
 en <^ i ^ St 
 
 PRACTICAL MAP READIKG. 
 
 Let us take the training map No. Ill, published separately, and 
 systematically read it, 
 
 Q. What is the scale of the map ? — A. It is 3 inches equal to 1 mile ; 
 that is, 3 inches measured in any direction on the map are equal to 
 1 mile on the ground. Any 1^ inches on the map will represent one- 
 half of a mile on the ground. We see that there is a representative 
 
FIELD OPERATIONS. 65 
 
 fraction on llie nia}). Tliis is onlv anotluT iiu-tliod of invlirating 
 the scale. 
 
 Q. How has it been detenuined ^ — A. Keineinbeiin*; that a repre- 
 sentative fraction is one rechiccd to unity in which the numeratoi- 
 represents the map distance and the dciioiniiiator the iiionud distance 
 we have: 
 
 Map distance .'{ inches :{ inciies 1 
 
 Ground distance 1 mile tW.860 inches 21,120 
 
 This may also be expressed 1:21,120; that is, one unit of measure 
 on the map represents 21,120 of the same units of measure on the. 
 ground. 
 
 ^ Ou observe that this ma]) lias no meridiau on it. How are you 
 to (U'termine directions^ A\'hen a map has no uieridian line it is 
 safe to assume that the reading matter runs from west to east and 
 that the u]) and down edges of the nuij) run north and south. A line 
 through Fairview Schoolhouse and Goodintent Schoolhouse runs 
 north and south. This line would serve as a meridian for work in 
 the center of the nuip and the borders for meridian lines along the 
 edges of the maj). Vou observe a little V-shaped marking at the 
 bottom of the map. The line to the right shows the true north, and 
 the one to the left shows the magnetic north; that is, the former, if 
 the map w^ere oriented on the ground, ]ioints directly to the north 
 pole and the latter to the magnetic north. There are comparatively 
 tew places on the earth's surface where these lines coincide. In this 
 case the magnetic declination is 7 degrees: that is, if you were to 
 take a bearing with a compass there would be a variation of T de- 
 grees from the tnie north. 
 
 Q. What is the direction of Hunterstown from Fairview School- 
 house? — A. North 52 degrees east. This is determined as follows: 
 Draw a line connecting P^airview Schoolhouse with the crossroads 
 at Hunterstown. DraAv another line connecting Fairview School- 
 house and Goodintent Schoolhouse. This latter is your meridian 
 line. Lay a protractor with its 0-180 degree edge along the meridian 
 with the center at Fairview Schoolhouse. Read along the edge of 
 the protractor to the point where the line connecting Fairview 
 Schoolhouse and Hmiterstown emerges from under the protractor. 
 This is tlie reading of the direction. 
 
 Q. AVhat is the direction of Granite Hill Station frt)ui Goodintent 
 Schoolhouse? — A. South 41 degrees east. Use the same meridian line 
 and pursue the same method as before indicated. 
 
 Note tho scale of map distances of contour intervals. Take the 
 space to the left of the scale marked 1 degree. This means that any 
 place on the map where the contours are spaced these distances 
 apart indicate that the grouud at that point slopes just 1 degree^ 
 Where the ground is steeper the contours are sjiaced closer together. 
 Bv keeping this scale in your mind you can tell by observation the^ 
 approximate slope of the ground at any point on the map. The 
 ability to understand contours so as to determine the slope or grade 
 of a road is of considerable impf)rtance in uiotor transport work. 
 
 1.WC)47— 10 5 
 
66 TENTATIVE MANUAL OF IXSTRUCTIOX. 
 
 Note the statement below the scale, V.I. : 20 feet. This means that 
 the vertical distance between contours is 20 feet. So you know 
 immediately that between every two contours, no matter what their 
 distance apart may be, there is a vertical difference of 20 feet. 
 
 Q. Suppose the map had no such statement on it? How would 
 you determine this contour or vertical interval? — A, By an inspec- 
 tion of the map. You will observe that the contours from the ridge 
 just south of Goldenville are numbered. These numbers indicate 
 that the vertical intervals between contours is 20 feet. 
 
 Q. What is the elevation of the Grubey House? — A. We see that 
 this house lies about midway between the 580 and 600 contours ; the 
 elevation is, therefore, about 590 feet. 
 
 Q. What is the difference in elevation between the McElheny 
 house and the Hamilton house ? — A. We see that the former has an 
 elevation of 540 feet and that the 640 contour passes through the 
 latter. The difference between these is 100 feet, so that the Hamilton 
 house is 100 feet higher than the McElheny house. 
 
 Q. Where is the highest point on the map ? — A. The 707-foot hill 
 west of Goldenville. 
 
 Q. Where is the lowest point on the map? — A. The lowest point 
 on any map will be found at the point where the largest body of 
 running water leaves the map. This will be found in the northwest 
 sector about 1,400 yards southeast of the Boyd schoolhouse. 
 
 In order to facilitate the further reading of this map take a package 
 of " crayolas " and proceed as follows : 
 
 1. With the blue crayola line out all the stream lines. This will 
 show at a glance all the water system of the country covered by 
 the map. 
 
 2. With the red crayola line out the 560-foot contour. This will 
 sliow" you the outline of the western watershed running along Oak 
 Ridge and its extension to the north, the watershed immediately west 
 of the main watercourse, and that to the east in the vicinity of 
 Hunterstown. 
 
 3. With your green crayola line the 500-foot contoui-. Make note 
 of its crooks and turns which indicate the shape of the ground 
 throughout its course, then compare the green line with the red line 
 indicating the 560 contour. You ought from this process to have a 
 very good idea of the country covered, by the map. 
 
 Tracing out the water system of the country included in the map 
 we find that the main watercom^se runs from northeast to southwest 
 practically parallel to the 549-583-501-543-531 road. Numerous 
 hranches lead off to the east and west, the main one to the east cross- 
 ing the above-mentioned road near 501, where it separates into two 
 ])ranches, one heading in the high ground in the southeast sector 
 of the map and the other in the high ground just M^est of Hunters- 
 town. The main branch to the west leaves the stream about 1,200 
 yards due west of 543, runs in a northwesterly direction to a point 
 700 yards southwest of the Varney place, and then turns northeast 
 and I'uns ])aiallel to the main stream to the Hermon place and form- 
 ing the watershed lying between the two streams. Another small 
 stream leaves the main stream and heads near the Boyd schoolhouse. 
 Another heads near the C. Topper place and runs a little west of 
 south, forming w'ith the main stream and its tributaries the water- 
 
FIELD OPERATIONS. 67 
 
 shed designated as Oak Kidge. Another small stream heads in the 
 vicinity of (ioldenvillf a)id runs soutlnvest. This and the branches 
 of the main stieam foi-m the Avatershcd which lies to the north in 
 |)n)lon<>ation of Oak I\id<ie. Over in the northeast sectoi- of the map 
 there is an in<le))en<U'nt >vsteni oF watercoui-cs that head to the south 
 of and in the vicinity of Ilunterstown, and these with the hranclies 
 fi'om the main stream form the watershed west ol" Ilunterstown. 
 
 A\'i(h your colored maj) yon will ho able to pick up all these points. 
 The study should leave you with a <>;ood mental ])icture of the coun- 
 try covered by the map. You should he al)le to approximate dis- 
 tances and to measure tlu' distance from one jjoint to another with 
 accuracy. You should have a Cfood idea of the ve<retation covering 
 the country and how it would look from any point on the nuip. 
 You shoidd have knowleda'c of the shape of the iiround. the steep- 
 ness of slopes, etc. 
 
FIELD OPERATIONS. 
 
 LECTURE VII. 
 
 LOADING. 
 
 TROOP LOADING. 
 
 (See (liagrani.) 
 
 The transportation of troops presents a number of features not 
 to be found in ordinary cargo transport, and company connnandors 
 must at all times be in a position to prepare their trucks for this 
 purpose at short notice. All portions of the truck equipment that 
 have been removed, such as covers, benches and boAvs must be kept 
 tooether where they can not be molested or lost, and can be readily 
 replaced on the trucks. The company commander Avill ascertain that 
 the oil, gasoline, and kerosene supph' of each truck is adequate, and 
 that the condition of the lamps is good. He Avill ascertain the prob- 
 able duration of the convoy and provide his men with food and 
 clothing accordingly. It must be remembered that the troop capacity 
 for a given truck includes the personal equipment of the troops, so 
 that, unless called for, extra baggage trucks need not be provided. 
 One cargo truck in each company will be left unloaded so that in 
 case a truck becomes disabled the troops will not be delayed. The 
 trucks will be equipped with seats 18 inches wide and extending 
 the full length of the truck on both sides. For number of men that 
 can be carried in trucks of various sizes, see loading table " Miscel- 
 laneous " at end of this lecture. 
 
 HAXDLIXG or GROUP COXVOT. 
 
 An officer is designated as connnanding officer of the convoy. He 
 has complete charge of all units of which it is comjiosed. He is 
 responsible for all necessary arrangements; the issuing of the required 
 orders. ])roper I'outing, and the discipline of its personnel. He 
 selects the assembly point where all the units meet to join the con- 
 \()V. and the times wlien they shall arrive at this point. He chooses 
 the resting and stopping places to be made by the convoy when en 
 route. 
 
 In order to <yet the trucks together an assembly point is chosen, 
 for example: There are 10 trains which are to operate as a group. 
 They are stationed at different points, and must be brought together. 
 A point is chosen near the area in which they are found; in most 
 
 69 
 
70 TENTATIVE MANUAL OF INSTRUCTION, 
 
 cases, a crossroad on the main road which the trucks are to follow. 
 A time is set when each train shall arrive at this point (the first 
 train at 5.30, second at 5.38, third at 5.30, etc., each train following 
 behind the other at three-minute intervals). The officer in charge 
 of the first train acts as a guide of the entire convoy. It is his duty 
 to lead the convoy along the route chosen by the commanding officer, 
 to keep and regulate the speed of the convoy, and in the absence of 
 the commanding officer of convoy to take command. The officer in 
 charge of the last train acts as a file closer for the entire convoy. 
 He is in charge of the repair outfit, and it is his duty to see that all 
 disabled cars are kept going, and to perform all the duties that are 
 required of the file closer. He will keep the commanding officer in- 
 formed at all times as to the location of delayed trucks, etc. The 
 officers of the companies act in the same capacity as the noncommis- 
 sioned officers of sections. They follow their companies, and in 
 general, place themselves in the rear of their companies. The train 
 commanders travel at the head of their trains. 
 
 Loading of troops must be carried out in a systematic manner con- 
 forming to the following specific directions: 
 
 All necessary arrangements for loading men must be made well 
 in advance of the arrival of the motor convoy. The convoy com- 
 mander must be at the loading point well in advance of the departure 
 to comi)lete such an-angeiiients as are necessary, and to reconnoiter 
 the loading ground. If he can not be present he must assign his 
 second in conunand to these duties. 
 
 When the convoy reaches the place of loading it should be halted 
 and faced in the direction that the troops are to be moved. If load- 
 ing is to be done near a town or city it should be carried out on that 
 side which is nearest the destination of the troops. 
 
 When the convoy has halted as prescribed and the necessary ar- 
 rangements have been made with the trcwp commander, each driver 
 will attend to dropping the tailboard of his truck and the arrange- 
 ment of the benches for the men. In the meantime, the noncom- 
 m^issioned officers in charge of each section will assemble the assistant 
 drivers of his section in column, single file, facing the troops, with 
 the men arranged in order of trucks, first truck first, then second, etc. 
 The assistant drivers of the first section are then n:iarched toward 
 the troops, the men of the other sections falling in behind. All the 
 assistant drivers are halted in file, just in front of the head of the 
 column of troops, and then execute " left face," facing center of the 
 road. Then the troops are successively marched off in blocks of 20 
 (or whatever may be the capacity of the truck), beginning with the 
 first truck, and each assistant driver takes charge of his section of 
 troops, marching at the head until his truck is reached, when he and 
 the driver of his truck attend to the loading of the men and the re- 
 placement of the tailboard. The noncommissioned officers of the 
 troops should be in the ranks in order to facilitate counting. 
 
 Xoncommissioned officers in charge of sections signal to the com- 
 l)any commander (or truckmaster) when their sections are loaded. 
 The convoy is ready to start only when all the sections are ready. The 
 officers of the troops are transported in the staff cars (2:)assenger cars) 
 of the convoy, as far as possible, otherwise they are assigned to trucks. 
 
 Unload the men, transported in the trucks, with the convoy headed 
 
FIELD OPERATIONS. 
 
 COMPANY FORMATIONS FOR TROOP LOADING 
 
 
 FIRST CONDITLDN 
 
 
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 SECON D CONDITION 
 
 FIRST CONDITION 
 ROAD SUBJECT TO LIGHT TRAFFIC 
 
 SECOND CONDITION 
 
 ROAD SUBJECT TO HEAVY TRAFFIC 
 
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 • -COMMANDING OFFICER 
 ©-TROOP COMMANDING OFFICES 
 A-TRUCKMASTER-1'-! SERGEANT 
 A - ASSTTRUCKMASTERS-5ERGEANTS 
 ■ -DRIVERS - CORPORALS 
 O-ASST. DRIVERS-PR IVATES.1SICL PRIVATES 
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 J STAFF CAR 
 
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 NUMERALS ALONG EDGE OF 
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/2 TENTATIVE MANUAL OF INSTRUCTION. 
 
 in such direction that the trucks will not have to double back and 
 mix up with the troops getting away. 
 
 CARGO LOADING. 
 
 (See tables.) 
 
 Because of the special problems arising under war time conditions, 
 definite methods of handling cargoes have been devised and nuist be 
 strictly adhered to in order to obtain good results. There is prac- 
 tically no limit to the classes of goods that the truck is obliged to 
 haul in active service. The requirement of the moment is the chief 
 consideration. Every item that goes into the load of a vehicle used 
 in war service is urgently needed. The necessity for correct handling 
 of cargoes can therefore be appreciated. 
 
 GENERAL LOADING CONSIDERATIONS. 
 
 To load a vehicle inefficiently not only reduces its carrying capac- 
 ity but endangers the safety of the entire cargo should the truck be 
 .subject to rough travel. A poorly loaded truck with a sw^aying cargo 
 is always in danger of overturning. Furthermore, one loose box or 
 crate can release an entire load. A correctly loaded truck has greater 
 carrying capacity. Its chances to reach its destination safely are far 
 greater than those of the poorly loaded vehicle. Overloading or un- 
 derloading are e(iually undesirable, and are to be guarded against. 
 For correct loading the following principles should be observed : 
 
 Heavy goods should be placed at the bottom and near the rear of 
 the truck body, and as nearly as possible over the rear axle in order 
 to give added traction. In building up a load, goods should be 
 equally distributed on both sides, as unbalanced loads Avill result in 
 swaying and, on rough roads, in broken springs. Hooks should 
 never be used in handling sacked goods. They must be firmly 
 placed. If they shift back and forth, friction will wear holes in the 
 sacks and loss of convents will occur. Flour (sugar, etc.) sacks 
 should be loaded with the filling end up. 
 
 Every load should be securely lashed, and if the truck is not cov- 
 ered, a tarpaulin should be placed over the load as a protection 
 against the sun, dust or rain. The required equipment for every 
 truck is two 60-foot lash lines, which should be sufficient to lash an 
 ordinary cargo. There is an additional equipment of 150 feet of If 
 inch rope in every train or command. 
 
 THE HAULING OF CARGO. 
 
 A top-heavy load is always dangerous, but in ruts and on corduroy 
 roads, it is a menace, i^n overturned truck may block a vitally im- 
 portant road. A truck with a load wider than the prescribed limit 
 is a danger, as it is probable that it will be too wide to pass large ve- 
 hicles on narrow roads. Corduroy roads are common in various 
 regions, and the truck driver must learn to be master of his truck 
 while driving o^er the logs that make up such roads. Although fas- 
 tened with stakes, a loose log is not an uncommon obstacle and its 
 ])resence may throw a vehicle from the road. If a truck keeps 
 
FIELD OTKItATIOXS. 73 
 
 ^(jUiiivly on tlio corduroy roiul, it is not >iil)jt'ct to skiddin*!,". llow- 
 vvvw once oti' the road, a truck is not easily re-covered. Slow, con- 
 stant s})eed is tlie first essential for safe ojjeration under these condi- 
 tions. The front wheels may cattli a<>:ainst a loose lo^ or in a 
 crevice and swerve the vehicle to one side and off the road. 
 
 J'he handlin<r of trucks at all loadina' places calls for similar pre- 
 i-aution. as a skid, collision, or o\erdri\(' into mud or sand can tic 
 up a hadly needed vehicle — perhap-. an entire section. Consideiablc 
 liackinf>' is necessary in all loadint;-. ( 'on>c(|uently thi' truck diiver 
 aiul his assistant should hi'conie proliiieut hoth in the handlinfj of the 
 wheel and in the execution ol' sio^mils. 
 
 Actual loadiuii oi- uidoadin*:; operations shonkl never be allowed 
 to interfere with the haudliu«i- of a conxoy. Truck drivers or as- 
 sistants are not to enaaiTe in any handlin<i- of car<?o. But. althou<rh 
 the j)ersoniu>l of a convoy does not actually handle goods, it is the 
 duty of those in char«>:e of trucks and sections to oversee loadinji" 
 and to riM|uire that ojoods are pro|)eily loaded into vehicles and se- 
 cui'ely la-lic(|. 
 
 \\'henever possible, information rc«»ardinti" the road to be traveled 
 -hould be <iiithered and. if necessary, extreme precatitions taken in 
 IfKuliiii;-. lashinii'. and operation. 
 
 Sl'r.< lAI, I,0.\1)IN(; ((iNSIUKItATIOXS. 
 
 After conferring- with the vai-iou> manufactnrers and others 
 interested in the loadin<;' of mateiial>, they ixive as a ijeneral 
 rnlc that (>() to SO per cent of the load -hould be carried by tlie rear 
 axle. 
 
 L)inih< r should i»e loaded with hea\ y tiuibers at the bottom, work- 
 in<r II]) with lighter nniterial. The method followed is to place 
 -taki's of Hat material, such as '2 by 4s (cut to the desired loading 
 height), around the bed every H feet from front to back. These 
 -upports will stay the load. They are placed inside and against tlie 
 side of the bed and held in place by the loaded lumbei-. Stakes must 
 never be nailed, but should be securely lashed. 
 
 Ho;i-((1 (/oofh will be found in cases of various sizes and shapes. 
 The method followed is to i)lace large and heavy boxes at the bot- 
 tom and to the rear, building \\\) until sufficiently high to i-ide. The 
 load or ca|)acity weight should not be exceeded. 
 
 lidhd (jtxuJx, consisting of hay. straw, blaidvets. can\as. and oc- 
 casionally clothing, will conu' in \ariou> si/es and weiglit--. Loads 
 must be confined to beds of trucks and neviM- be extended ovei- the 
 «>ides. When the end gate is cluiined flush with the floor the load 
 may extend beyond the bed length. The longer bales are loaded 
 first, and. when lising above the bed. should be slanted l)yrandd 
 style and as close together as possible. 
 
 Sti/'h-< ij (/(xuls are |)rincipally forage and food supplies. Kxtreme 
 care sht)uld be em|)loved in loading, handling, and transporting >uch 
 material to prexcnt shil'tingon I'ough i-oatls. When the lied has l-.een 
 filled the sacks should be |)yraniided until then* is but a single row 
 on the top parallel to bed length. Such a load should be lashed and 
 covered with special care. 
 
 Bavt'chd (/oodx are diHicidt to load, especially when there is no 
 specially constructed bed. If heailed, b;in-el on bai'rel. until the 
 
74 TENTATIVE MAISTUAL OF INSTRUCTION. 
 
 tox^ of the bed is reached, they should then be pj^ramided in such 
 a way as to alloAV the barrels to fit in a row of two's and cover a 
 lino between the two of the layer below. Unlieaded barrels, or 
 barrels covered only with burlap, should be stood on end and care- 
 fully lashed. A load of unheaded barrels is of course materially 
 lighter than one of headed barrels. 
 
 Bundles will be found to consist principally of canvas. The load- 
 ing of this material is comparatively simple. With large Inindle-- 
 first, pyramided after bed line is reached, such a load will ride well. 
 
 Crafc-fl (joods consist of hardware and food supplies and nnist be 
 loach^l with hea\y goods at the bottom and to the rear of the truck. 
 ^\ ith light fragile crates on top. 
 
 Loose mciterial presents the greatest loading problem. Such uia- 
 terial is usually hardware, farm implements, and such items as cans, 
 AvheelbarroAvs, trench walks, rolls of barbed wire, coils of spring 
 wire, dugout material, and princi])ally semielli])tic corrugated iron" 
 about 10 feet in diameter. Mixed loads prevail in handling loose 
 material and must be made up according to the nature of the material 
 on hand. The use of nuich common sense is the only rule that can 
 be laid down. Every bit of available space should be utilized with- 
 out overloading. 
 
 INSTRUCTIONS FOR HANDLING AMMUNITION. 
 
 In handling all types of annnunition, care must be taken that 
 crates are not broken or. if uncrated, that the copper bands at base 
 of shells are not scratched or deformed. 
 
 Damaged l)ands render tlie shells not only useless Init daugerou- 
 to fire. 
 
 Do not allow colors painte«l on shells to be effaced. They were 
 put there for a purpose and are necessary. 
 
 Protect ammunition from sun and rain: both are harmful to tlie 
 high explosive filling. 
 
 When fuses are attaclied to shells, do not handle by fuses; you 
 may destroy the protective cover and ruin the fuse. Where fuses 
 are not attached, plugs re})lace them. Should one of these fall out. 
 l)ut it back at once. 
 
 When handling gas shells, be jjrovided with a mask to protect 
 against leaky shells. 
 
 All ammunition is highly explosive, therefore dangerous. Do Udt 
 smoke while moving it. and h-muUe irifh cnre. 
 
 Overloeulmg should be carefully avoided. The greatly increase<i 
 wear on tires, the breakage of springs, and the strain to which all 
 parts of the mechanism and chassis are subjected greatly outweigh 
 any advantage gained l\v hauling more material and making fewer 
 trips. 
 
 LASHING. 
 
 P^quipment for lashing loads on trucks consists of the two BO-foot 
 lengths of rope provided, and the lash hooks or rings through which 
 to pass the lines. After the first tie at the front side has been made, 
 a rope is passed over the top of the load (adjusted to pass over some 
 
FIELD OPERATIONS. 
 
 75 
 
 article which liin(l> <i()<)(|s IxMicath it) and liroiiohi down on the oj)- 
 posite side. It is not br()U<i;ht thi()ii<:h the hook or rino- directly op- 
 jx'site the other side, but the one just haeU or to the rear of it. The 
 rope is then hroufiht back over the top. This process is repeated 
 until tlie rear of the truck has been reached. Tt should be borne in 
 niiud tliat only every other liook oi- j-iu*:; is used in attachinji:. 
 
 When this pi'ocess is completed, the extra rojx' is used. startiu<>' at 
 the opposite side, and criss-crossed to tlu' lear of tin- truck to ef- 
 fect the >aine opei-ation as with the lir>t lope. I'his ro})e also is 
 attaclied only to e\ery other hook or rin<i'. The load will so bind 
 that not]iin*r less than a complete turuoxer will >|)ill i(, |)ru\idetl. of 
 coui--e. that it is correctly stacked. 
 
 iMcn'iTNc ovKirrrifM-.i) iiacK. 
 
 It i- no( unu>nal for a tr'uck t»^ turn o\ci'. cillier through faulty 
 Icadiuii' or tVom unaxoidable causes. es])('cinlly on bad loatU at 
 nifrht. 
 
 In the event of a turiioxcr. oidy that \)-Mi of tlu- load that has 
 broken away from the lashin<:s is to be removed. Directly opj)osite 
 tlie middle of the vi'hicle and about -\0 feet away, two stakes of con- 
 venient materials are driven about 4 feet ai)ar(. lilock and tackh- 
 are attached by means of a britlle. One block is .ittached to stake, 
 and the other to the two wheels in the air. If usinp sin<;le and 
 double blocks, the single block is attached to the stakes and the 
 double attached to the vehicle. Mechanical, hor^e or liand ]:)ower is 
 effective. 
 
 The followino- li>t of engineers' supplies aiul aniiuimitiou gives 
 some idea of the mat(4'ials to be carried. A table of weights is also 
 sui)))lied to give the student an idea of the relative weight of various 
 arti(de> aud the (piautity that uia\' be. with >afet\'. loadeil into a 
 truck : 
 
 Quantities \rhich can be loaded into motor tniel:>i. 
 
 MISCELLANEOUS. 
 
 Articles 
 
 Loaded and lashed. 
 
 How packed. 
 
 350 gal. 
 
 Oasoline tanks oORallons.full 
 
 I 50 gallons, cinpt v 
 
 13 Rations, full i 390(ral.30i 
 
 13 Rations, empty 
 
 Tires, pneuinatii 
 
 Mail bass 
 
 Tarpaulins 
 
 Barrack bags 
 
 Trunk.s, .\rmv.. 
 
 Men ;... 
 
 Po 
 
 .\ssorted sizes . 
 
 Baceape 
 
 Without bangage. 
 
 
 3 tons. 
 
 tous. 
 
 
 700 gal. 14 
 
 l,.350gal.27 
 
 10 
 
 30 
 
 30 
 
 30 
 
 0.50 gal.. 50 
 
 9SS pal. 70 
 
 S4 
 
 125 
 
 125 
 
 75 
 
 1.50 
 
 1.50 
 
 30 
 
 50 
 
 60 
 
 25 
 
 .50 
 
 70 
 
 25 
 
 50 
 
 70 
 
 30 
 
 00 
 
 60 
 
 12 
 
 20 
 
 25 
 
 IN 
 
 35 
 
 35 
 
76 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 (Jii<nitili( s irlnch run he loinhil i)itii motor tnicka — Continiifd. 
 ENGINEER STORES. 
 
 Barracks, "Adrian" (21 by 98 feet) 
 
 Bricks 
 
 Camouflage, finished, rolls of 20 square yards 
 
 Cracked stone, cubic yards 
 
 Cem3nt, barrels (4-loi) poiund bags) 
 
 Corrugated iron, sheets, square feet 
 
 Duck boards (6 feet 6 inches by 1 foot 6 inches) 
 
 Expanded metal, large mesh, square feet 
 
 I-beams, 4-inrh, 12 feet long, pieces 
 
 I-beams, 6-inch, 16 feet long, pieces 
 
 Lumber, feet b. ra 
 
 Nails, all sizes, 100-pound kegs 
 
 Paint, 50-gallon barrels 
 
 Pickets, wood, 50 per cent long and 50 per cent short 
 
 Posts, angle iron ( 50 per cent 5 feet 10 inches long) 
 
 Posts, angle iron (50per cent3teet 6 inches long) 
 
 Posts, screw, 50 per cent long and 50 per cent short 
 
 Rails, 10 to 12 feet long, 25 pounds per yard 
 
 Rails, 15 feet long, 35 pounds per yard 
 
 Revetting, fascines, 10 inches by 9 feet 
 
 Revetting, gabions, 2 feet by 3 feet 2 inches 
 
 Revetting, hurdles, 7 feet 3 inches by 3 feet 2 inches 
 
 Road planks, 5 inches by 9 inches by 9 feet 
 
 Roofing felt (216 square feet, rolls) 
 
 Sand bags, number ^ 
 
 Shelters, steel, large, complete 
 
 Shelters, steel, small, complete 
 
 Round posts, 6-inch, rough, linear feet 
 
 Tar, waterproofing, 50-gallon barrels 
 
 Ties, for narrow gauge, 4 feet 6 inches by 6 inches by 4 inches. 
 
 Telephone conduit cable spools 
 
 Wire, barbed, 50-pound rolls. 
 
 li-ton 
 truck. 
 
 750 
 80 
 
 n 
 
 12' 
 
 1,200 
 
 100 
 
 1,600 
 
 40 
 
 20 
 
 800 
 
 30 
 
 4 
 
 350 
 
 500 
 
 500 
 
 700 
 
 40 
 
 20 
 
 30 
 
 25 
 
 50 
 
 30 
 
 80 
 
 10,000 
 
 1 
 
 2 
 
 300 
 
 10 
 
 80 
 
 1 
 
 60 
 
 3-ton 
 truck. 
 
 1,500 
 
 100 
 
 3 
 
 24 
 
 3,000 
 
 150 
 
 2, 500 
 
 80 
 
 40 
 
 1,600 
 
 60 
 
 9 
 
 500 
 
 1,000 
 
 1,000 
 
 1,400 
 
 80 
 
 40 
 
 35 
 
 32 
 
 75 
 
 60 
 
 130 
 
 15,000 
 
 2 
 
 2 
 
 600 
 
 20 
 
 160 
 
 2 
 
 60 
 
 0-ton 
 truck. 
 
 2,500 
 
 120 
 
 5 
 
 30 
 
 3,000 
 
 150 
 
 2, 500 
 
 no 
 
 65 
 
 2,500 
 
 80 
 
 14 
 
 500 
 
 1,700 
 
 1,700 
 
 2,400 
 
 110 
 
 70 
 
 3.5 
 
 32 
 
 75 
 
 100 
 
 130 
 
 15,000 
 
 2 
 
 2 
 
 1,000 
 
 24 
 
 260 
 
 3 
 
 60 
 
FIELD OPERATIONS. 
 
 
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78 
 
 TEXTATIVE MANUAL OF INSTRUCTION. 
 
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FIELD OPERATIONS. 
 
 LECTURE VIII. 
 
 CONVOY PROBLEM.' 
 
 Till' follow iiiii' |)1-oIiKmii is itixcn :i> a >iiu|)l(' cxiiiiipli' of conditions 
 lo 1)1" i"o\n)(l and situations to In* nu't in motor transi)oit work. 
 
 The connnaniU'r of" tiu' -lOth Motor Transport Company at Two 
 Taxi-rns. opi4-atin<r -'^-ton trucUs. i-> Ld\ino- (lie followina' Iransjioit 
 oi(|(>r at !> p. m. An.i>iist '20, 11>11». 
 
 MOTOK riiANsrour oki)i:u. 
 
 ('H-dcr .\'(). 2.">: (late. .\u;:usi lio. l<.)in. 
 
 rridii ciminiaiHliiVi utrufi-. 4tli .Miiior 'l"r.iiis|:.>ii Triiin. 
 
 'i"<i coiiiiiiaiuliimoltict'i-. 2O1I1 .Moior 'rriiuspuii ("uips. 
 
 Villi will fui-iiisli iiKiinr tiaiisiKirtalioii ;is follows: 
 
 Report for loinliii^. 
 
 I To traiis- 
 
 I I port 
 
 To At -p , a.„ „, I tons, 
 
 (place), (timci. T.M,.tt.cer). 
 
 ' Two tav- 
 erns. 
 
 8.10a.m. Command- 
 .ViiR. inR ofTi- 
 
 21. 
 
 2 companies 
 'nfantry. 
 
 cer Com- ."ifMI men. 
 panie.-i C 
 and H 
 lOtli In 
 fan try. ■ 
 
 Report for imloacling. 
 
 To 
 (place). 
 
 Round 
 Hill. 
 
 At 
 
 (time). iTo(olTicer). 
 
 .5 p. m. i Command- 
 Aug. inR ofTi 
 
 21. 
 
 Route and re- 
 marks. 
 
 Load with sal- 
 ...s V,...- vapeat Koimd 
 cor 2d Hill an<l do- 
 Hat t al- I liver sanio to 
 ion. lOth 1 salvaro plant, 
 Infantry. dot t yshnn;, 
 ] on .Vu!.'. 22. 
 Bridjes north 
 of Newchester 
 not ■ passable 
 by trucks. 
 
 Half of e.xcciitioii of ortk'r. .\ii;nist :jl and I'L'. IHIO. 
 
 Total iiuiiihcr of vcliicK's. 
 
 <,>nler received at (I'lace) (Vmeteiy lllil. 
 
 (Tiiiiei !> p. 111. 
 
 ( 1 Mite I .\iimisi 2t». lill'.t. 
 
 Signed .1. Siiiitli. 
 
 liaiik IMrst l.ifUtniaiil . Moior 'rraiispoil ( "oi]is, coiiiiiiaiid- 
 
 iiiu ^nili .Motor Tiaiisiiori ( "oi'ps. 
 
 (Siiiiiedi (iKO. Hkow.v, 
 
 Uaiik. <'aptaiii. Motor Transport Corps. 
 
 ' To be solved ou CJcttysbuiK map t'nited States <T('ologlcal Survey. Scale of 
 Is assumed to be three miles to the inch for convenience In handling a single map. 
 
 79 
 
 map 
 
80 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 (Back of form.) 
 
 a — This form is filled out by the person who directs the moveineut of com- 
 panies, sections, or individual trucks. It is made out in duplicate, and when 
 delivered to the officer, or other person who is to carry it out, the place, time.. 
 and date of receipt of the order shall be entered and statement sijined. After 
 the order has been carried out. and the date entered, as to truck numbers, 
 tonnage, etc. the original copy will be signed aijd returned to the office or other 
 person who issued same. The duplicate copy will l>e retained in the company 
 records. 
 
 h — The space below is to be tilled out by connnanders of companies, sections.. 
 and by individual truck drivei-s after they have carried tmt this order. 
 
 ""r!ri||l 
 numbers, t™. 
 
 Estimated mileage. 
 
 Indi- ; Indi- 
 Hour of vidual i vidua! 
 return. truck ; truck 
 mimbers.' tonnage. 
 
 Estimated mileage. 
 
 Hour of 
 
 Loaded. 
 
 Empty. 
 
 Loaded. 
 
 Empty. 
 
 return. 
 
 
 
 ! 
 
 
 
 
 c — state below any changes that were made in this order with regard tc 
 cargo, loading or unloading i)laces, route, or time and by whose authority. 
 
 d — Give below a report of general conditions during the day, making special 
 mention of any accidents, delays, vehicles repaired on the roads, conditions at 
 loading and unloading places, and any suggestions that will make for the- 
 betterment of the service. 
 
 Signed 
 
 Rank 
 
 After readino- the transport order, the company comnjander must 
 make an estimate of the situation. He finds that he is required to. 
 transport 2 full companies of infantry from Two Taverns to Round 
 Hill, to load at Two Taverns at 8.10 a. m., and unload at Round 
 Hill at 5 p. m. At Round Hill he is to load Avith salvage 
 material and deliver same to salvage plant at Gettysburg on the fol- 
 lowing day. He also notes that bridges north of Newchester are not 
 passable by trucks. Having this task before him, he next proceeds to 
 survey his means for accomplishing it. He finds that of the 27 trucks 
 assigned to his company, one of them is out of commission in the 
 service park. The other 26 are available and since the capacity of 
 each truck is 20 men, he has just enough for this convoy, allowing 
 1 empty truck for emergency use on the tri]x He then considers 
 the personnel which he has available, taking into account men who. 
 are sick, absent, etc. 
 
 He knows that he can go 4 miles on 1 gallon of gasoline per 
 truck and from informal inspection made that afternoon, he knows 
 that all gasoline tanks of his company are about half full, conse- 
 quently all tanks must be refilled before leaving. This will take the 
 convoy to Rotmd Hill and about half way back, so he orders a tank 
 truck to leave camp at 8 a. m. August 22 and to meet the convoy at 
 Brush Run. Two Taverns is 14 miles. He must be at Two Tavern? 
 at 8.10 a. m. therefore, he should leave his camp about 0.30 a. m.. 
 From his map he selects his itinerary from Two Taverns to Bonneau- 
 ville. to York Pike, to New Oxford", to Carlisle, and Baltimore Pike 
 to Round Hill, a total distance of 54 miles. He has 8 hours and 50 
 
FIKLl) orERATIONS. 81 
 
 miimtes allowod liiin in wliich to cover tliis distance; that is, from 
 8.10 a. ni. to 5 j.. in. He allows one-half hour for loading troops 
 and 1 hour to stop for dinner, leaving- 7 hours and 20 minutes 
 actual running time, oi- something less than s miles per hour. 
 
 lie now considers the ([uestion of feeding his men. Since he will 
 lie gone nearly two days and overnight, he decides to take the kitchen 
 trailer to insure proper issue of hot food to the connnand. 
 
 He therefore about 10 p. m. issues a company tiansport order to 
 hi- truckmaster in the following form: 
 
 COM CAN V IHANSl'OltT OKDKi:. 
 Order No. ]s, Truck ('i.uiiiaiiy No. 'JO. date: Aiiti. .20. 1910. 
 
 1. Date of niis.sion, August 21. 
 
 2. Nature of mission, troop convoy. 
 :\. Number of trucks. 2G (1 empty). 
 
 4. Truck number.s, all trucks except No. \1V1{\ and Idlcln'M trailer. 
 
 'i. (Juide. Seri:t. Peters. 
 
 f>. FiK- closer, Ser^^t. Williams. 
 
 7. Second section. Sergt. .Tame.s. 
 
 s. Tliii-d .section, Serjjt. Gibbs. 
 
 !>. Startinti liour. (i.HU a. m. 
 
 10. Itinerary (iMupty). Baltimore I'ike to Two Taverns. 
 
 11. I.oadinj; jxiint. Two Taverns. 
 
 12. Loading hour. S.IO a. m. 
 
 13. Nature of load, 500 men (2 companies Infantry). 
 
 14. Tonnasre or numbei- of men per truck, 20. 
 
 ].">. Itinerarv (with load). Two Taverns, Bonnenuville, .'lOS, 'u'A. York IMko, 
 Brush" Itun, New Oxford, r.Sl, C. and B. Pike to Bound Hill. 
 
 ICi. I'ldoadin^^ Point, Bound Hill. 
 
 IT. Itinerarv (return), C. and B. Pike, York Pike to Gettysburg to Cemetery 
 Hill. " * 
 
 15. Remarks (covering meals — Refilling) : Stop for dinner east of New Oxford; 
 
 supper and breakfast August 21, at Round Hill; load with salvage at 
 Bctund Hill on August 22 and deliver same at salvage plant, Gettysburg; 
 till trucks with gas and oil before leaving. One tank truck, tilled, will 
 leave camp at 8 a. m. August 22, <\nd meet convoy at Brush Bun on York 
 Pike. 
 
 Signature J. Smith, 
 
 FirKt Lieuieiifint, Motor Transport Corps. 
 
 This order covers in a uniform and systematic way all necessary 
 details for the movement. It indicates" to the truckmaster all the 
 things that he must arrange for, and he sees that all the necessary 
 minor duties are performed by all the various members of, the com- 
 pany concerned, such as the assistant truckinasters. cooks, etc. 
 
 The company commander arrives at the park about «> a. m.. August 
 '21, makes an informal inspection of everything, sees thtit the guide 
 has the itinerary correctly, starts him off at G.-JO. sees that the other 
 trucks follow at proper intervals, and him.self falls in at the end ot 
 the column (.see Lecture III, General Principles of Convoy) .^ 
 
 130647—19 6 
 
FIELD OPERATIONS. 
 
 LECTURE IX. 
 
 KNOTTING AND SPLICING. 
 
 It is sii^^eslc'd tliiit a hoard of the \anoiis l<iiot>. ticil. attarluMl, 
 and lalxdod foi- instruction purposes be used. 
 
 The art of \vorkin<i- in ro^x' ran not be learned IVoiii a book, but 
 the ilhistrations which folhnv are used to fjive an idea of the uK^st 
 coniinon knots and splices of value to truck operatoi's and should be 
 studied and mastered. 
 
 There are three qualities to a good knot : 
 1. Rapidity with which it can be tied. 
 '2. Its ability to hold fast when pulled ti»>ht. 
 3. The readiness with which it can be undone. 
 To understand clearly the exp^anations and descriptions of the 
 \arious knots, one must have clearly in mind the principal parts of a 
 rope (see fio-. 1) : 
 
 Fi<;. 1. Ft.; J I"i'.. :'.. 
 
 (i) The standiufr part — tin- lonii" unused portion of the rope on 
 which he works. 
 
 ("2) The l)ight — the looj) or hitch formed wlu'Uevcr the rope is 
 turned l)ack upon itself, and 
 
 (:>) The end — the part he uses in leading. 
 
 The following knots are mo.st commonly in use by truck driver^: 
 
 Fig. '1. Stjiiiiic or reef k)iot. — The counnonest for tying two ropes 
 together, \e^■er slij)s oi- jams: easy to untie. 
 
 Fig. 3. Sl'ij, or rKunhu/ kitoi. — A bight is lirst formed and an 
 overhaul knot made with the end aiound the standinu' part. 
 
 83 
 
84 
 
 TENTATIVE MANUAL OF INSTRUCTION, 
 
 Fig. 4. The howUne.—A noose that neither jams nor slips. Form a 
 small loop on the standing part leaving the end long enough for the 
 size of the noose required. Pass the end up through the bight. 
 
 Fig. 5. 
 
 Fig. S. 
 
 around tlie standing part, and down through the bight again. To 
 tighten, hold noose in position and pull standing part. 
 
 Figs. 5 and 6. Bowline on a hight. — Used in place of a single bow- 
 line where ereater strength is needed. 
 
 Fig. 9. — Caf.s-paw. 
 
 Fig. 10. — Round turn and 
 two half hitches. 
 
 Fig. 11. — Sheet bend or 
 weaver's knot. 
 
 Fig. 7. Clove hitch. — Used to fasten one pole to another; this knot 
 holds snugly and is not liable to slip laterally. Hold the standing- 
 part in left hand, then pass the rope around the pole, across to the 
 standing part, making a second turn around the pole, and pass th(i 
 end under the last turn. 
 
FIELD OPERATIONS. 
 
 85 
 
 Fig. S. Tiro half hitches. — Useful becau>e tlu'V arc easily made 
 nn<l will not slip iiiulor any strain. Their toniiation is siitficiently 
 indicated by the ilhistration. 
 
 Fig. y. The cdfs-paw. — Can be u^ed when both ends of the roi)e 
 are not available. It will not slip. 
 
 Fig. 10. Round turn and ttro half h/frhcs. — This may l»e used 
 jii'ound an axle. 
 
 Fig. 12.— Blackwiill hitch. 
 
 Fig. 11. — Sheet hend or weavers knot. — Used in tying two rope 
 vnds togetiier. ISfake a bight wltli one rope AB. then pass C of the 
 othei' rope up through and around the entire biglit and bind it 
 under its own standing part. 
 
 Fig. 1-2. BlacK'uudI hitch. — Used to secure a rope to a hook. The 
 standing ])art when hauled tight holds the ends firmly. 
 
 S|)lieing is joining the ends of two ropes pei'manently or bending 
 l>aek the end of a rope uj^on itself to form a permanent eye. 
 
 The following are the few methods of sidicing in use: 
 
86 
 
 TENTATIVE MANUAL OF INSTRUCTION. 
 
 SPLICING. 
 
 1. Eye i<plice {^fraixled rope) (fig's. l:^-l()). — The rope is unlaid for 
 perhaps a foot from the end. and the strnnds l>rono;ht back iipon the 
 body of the rope at a ])()int wliich will form nn eye of the size that is 
 
 Fig. 3H. 
 
 Fig. ir 
 
 Fig. 1G. 
 
 desired. J>eoinnin<>- with any one strand, this is tucked from left to 
 right through the strands of the rope, being passed over one and 
 under the next. The other strands are similarly tucked always from 
 
 right to left. All :ire then trimmed down to two-thirds their original 
 size, tucked again, trimmed to one-third size and tucked a third and 
 
 Fig. 18. 
 
 last time (see illustration). Where the rope is of four strands, the 
 first strand is tucked under two; but this for the first tucking only. 
 
 Fig. 19. 
 
 2. Hhort splice (figs. 17-19). — Two ropes are unlaid for a short 
 distance and married together with strands interlacing. The strands 
 are then tucked through the lay of the other rope exactly as has been 
 described in the case of an eye splice. 
 
FIELD OPERATIONS. 
 
 87 
 
 3. Lon(/ splhr (Hos. '20-21). — Heiv the n>i)i'> arc iiiilaiti for a 
 jli-eiiter distance than for a short splice, and the ends hiouoht 
 ro<»-ether as before, with strands interh\cin«:-. In>tead now of tuckina- 
 at'~once, we i)roceed as folh)Ws (see illnstration ) : Unhiy a 1. «mh' of 
 the strands of A, for a considerable distance, and in place of it lay 
 np b-1 tlie adjoininf; strand of P>. thus working- m strand of li into A. 
 for. say. a foot and a half or two fei'l. For convenience now twi<t 
 up a-1 and b-l tooether temporarily, as illustrated. Turn the rope 
 
 ^^^^SB 
 
 a3 
 
 Fig. 20. — Eye splice. 
 
 end for k^\\^\. iiiday 1) i'. one of the strands of H. and in i)lace of it 
 lav up a--i, the adjoininj-- .strand of A, a-3 and b-o aie left lyinu; 
 beside each other without beino- unlaid. We now lia\c three pairs of 
 stiands at diti'erent points of the rope, lie^innino- with a-2 and h-l 
 (for exani[)le) separate each strand, overhand knot these to<rether and 
 tuck them as in a short splice, over one and under one of the full 
 reniainin«i- sti-ands of the rope. The other \yaw> of st muds (a-1 b-l ) 
 (;j_-j l5_>2) juv similarly reduced. knotte(|. and rnck'cd. The spare 
 
 aJ h 
 
 I.— Loiip splii 
 
 half of each strand is trimmed ot! smooth as.are the end- of the other 
 halves after they have been tucked. 
 
 Rope is measured by its circumference. A four-strand rope is about 
 one-fifth weaker than' a three-.strand one. Blocks should be at least 
 three times the size of the rope which it is intended to seive in them. 
 The haulinji i)art l)ears twice the strain of the standino- part of a fall. 
 
 liiralimi ufniins. — S(|uare the circumference and divide by 3 for 
 the bieakinof 'strain in tons: divide by i) for the proof strain, by (> for 
 the working straii\. 
 
FIELD OPERATIONS. 
 
 Lr:cTri{K x. 
 
 TECHNICAL INSPECTION. 
 
 Technical inspection of MKjtor ('(|uipincnt will be made under the 
 direction of a conii)any oHicer and the mechanic and at periods when 
 it is most convenient to d(j the work without interfering^ with the 
 routine truck details. Inspection of all the etiuipment will lie made 
 at intervals not to exceed 10 (hivs. 
 
 Xo repairs sliould he sent to the shoj) which can he })roperly madi' 
 by the comi)any mechanics. If this is carefully checked, much time 
 may l)e saved, as the truck would not remain idle in the >hop. 
 
 The following list will indicate the (jjeneral questions that must be 
 satisfactorily answered in a tiiorou^h inspection: 
 
 TkCJIN ICAL I XSPPXTIOX. 
 COOLING SYSTEM. 
 
 Radiator: 
 
 (a) Are there any leaks? 
 
 (b) Will water How from dinin cock? If >o, is it very full of 
 
 sediment ? 
 {(■) Is the pa^saae of air tliiouiiii (lie i adiator obstructed bv dirt. 
 
 etc.? 
 {(/) Is the filtei' in position, and the ovci'flow pijx' clear? 
 
 Hose connections: 
 
 (d) Do any of the conectious leak? 
 
 (h) \)i) any of the connections >lio\v wear and need reidacincf? 
 Circulation : 
 
 (tf) Is the fan in jrood workin<r order ? 
 
 (b) Is the belt in <2.ood condition ? 
 
 (c) Is the fan bracket tight? 
 
 {(f) Does water circidate freely? (Take ladiator cap otl' while 
 
 motor is runnino; and observe circulation.) 
 (( ) If eipiipped with thermostat, does it function? 
 (/) Does i)ump leak ai'ound shaft? 
 
 Moldi;. 
 
 Compression : 
 
 (a) Te.st the compre»ion by switching otl' the ignition and 
 
 slowly cranking by hand. ( )pen all the comi)ression cocks 
 except the one on the cylinder l)eing tested. Test eacli 
 cylinder in turn, always ])nlling up on crank to feel the 
 compression. This should be done when the motor is 
 warm. 
 
 [b] Exannne cylinder head joint (if detachable head mot<jr), 
 
 valve cap plugs, and pet cocks for leaks. 
 
 80 
 
90 TKXTATIVE MANUAL OF INSTRUCTION. 
 
 Valve adjustnieiit : 
 
 {a) Test tappet .settings for proper adjustment. See vehi- 
 cle mannfactnrer's instruction book for tlie pi'oper 
 clearance. To test clearance, have engine revolved slowly 
 until tappet is in its lowest position, try different leave- 
 of a "feeler gauge" between the tappet and valve stem, 
 the leaf that '' just goes " is tl>e amount of clearance. Do 
 not report in detail; simply state " O. K." or "to l)e read- 
 adjusted."' 
 (Toveriior : 
 
 (a) If a vehicle has a governor, is it in Avorking order? The, 
 condition can best be determined by driving or i-oad test. 
 {!)) Does governor show signs of having been tami)ered with i 
 Carburetor: 
 
 (a) Does the float overflow ? 
 
 (b) Does the motor idle at proper speed? 
 
 (c) Are the gas connections tiglit? 
 Controls : 
 
 {a) PLxamine ball joints and yoke and [)in joints of spark and 
 throttle controls foi' lost motion and proper functioning. 
 Oiling system : 
 
 {a) If pressure system, does the dash pressure gauge show 
 proper pressure when motor is running? 
 
 (/>) Che;-k oil le\el in crank case. 
 
 ( () Is oil in crank case in good condition and free from grit i Is 
 the proper grade being used? 
 
 (d) Is oil filter in position and clean? 
 General : 
 
 (a) Are all bolts tight? 
 
 (h) Examine crank-case arms for cracks. 
 
 {(■) If eno'ine is susi)ended from su})port beams, are the brackets 
 
 tight? Is the support pin worn? 
 ((/) Does engine "knock" from carbon? 
 
 (e) Does the engine *' knoi-k " from loose bearings? 
 
 (/) Does the starting crank engage and disengage properly? 
 
 IGNUJION AND ELECTKIC SYSTKiVf. 
 
 Magneto : 
 
 (a) Is the distributor clean? 
 
 (b) Is the breaker box clean? 
 
 ((■) Test the magneto by disconnecting the cable from one spark 
 plug at a time and holding the end of the same approxi- 
 mately j\ of an inch from some unpainted metal part and 
 observe whether or not spark jumps the gap while the en- 
 gine is running. 
 
 (d) Is the couplino- in good condition? 
 Cables: 
 
 (a) Examine the high and low tension cables foi- broken in>u]a- 
 tion or signs of wear on the same. 
 Spark plugs : 
 
 (a) Have sjjark })lugs remoAed and examine them for proper 
 setting, cleanliness, and cracked or broken porcelains. 
 
FIELD OPERATIONS. 91 
 
 Cieiieialor : 
 
 (a) Ascertain if the generatoi" is opeiatiiig [jroporly by observ- 
 ing^ the voh meter or aniiueter while the engine is running. 
 Also clietk the approximate speed of cut-in and cut-out. 
 See manufacturei'V iust imt i(»n I Us for details concern- 
 ing the generator. 
 
 (A) Are the wii'e connections on tlic gciicralor tight ? 
 
 («") Is the connniitator cleans 
 Starting motor: 
 
 (a) See thai wire connect ion:~ arc tight and try the motoi' for 
 ( orrcct ojx'ration. 
 Battery : 
 
 {<') Test the condition ol" the batlci\- witli a hydrometer, 
 (iiavity between 1.-J7")-1.;5(I0 indicates battery in a fully 
 charged condition, (iravity between 1. 2(10-1. 'J T") indicates 
 battery is moi-e than half chai-geil. (ira\ity ixdow l.-JOO 
 i'lit above l.l."i() indicate- l)attery le-.- than half charge<l. 
 (n':i\ity below l.i.'td indicato tli;ii the baltei'v is in a run- 
 down condition. 
 
 (/>) Ai-e the battery holding down devices tight ( 
 
 (r) Is the batterv (decti-olite up to (he proper height '. 
 
 (if) Is the battery clean ^ 
 
 (r) Are the batteiT terminal connection^ tight ^ Are they 
 corroded '. 
 Instruments : 
 
 (ti) Examine the dash instrnment> foi- condition and opeiation. 
 A!' i ring: 
 
 (<i) Kxamine the wii-ing comu'ctions foi- tightness. 
 
 (Ii) Does insulation show weai-^ 
 
 ( (■) Are |)rop(>r fu-o in place ( 
 
 V\ \.\. S> S'IKM. 
 
 (iasoline taidv : 
 
 {(i) \\v the fastenings tight? 
 
 (A) Kxamine the tanU' bu' leaks. 
 ( ijisoline lines: 
 
 (f/) Examine all tit tings for leaks. 
 
 (A) .Vic the lines pioperly sn])porte(l? 
 
 riJANSM ISSION S^ SIK.M. 
 
 Cliitc-h: 
 
 (d) Does the clulcli disengage freely and properly? 
 
 {!>) Are the disengaged thiiist faces ;ind disengaging fork 
 
 fingers badly worn '. 
 {(■) Is the lubrication proper? 
 {(l) If a cone clutch, is the leather in good condition: if disk. 
 
 are the disks in good condition? 
 (r) Are the ))edal shaft busliings badly worn ^ U the action id' 
 
 the pedals coi-rect ? 
 (/) Is Hie clutch bi-ake effectived 
 
92 TENTATIVE MANUAL OF INSTRUCTION. 
 
 Gear box : 
 
 («) Does the case show aii}^ signs of cracks or oil leaks? 
 (h) Are the bolts which hold it in position loose or worn :' 
 
 (c) Is the lubrication of the proper type and at the proper 
 
 height ? 
 
 (d) Do the gears engage and disengage freely? If the gears 
 
 do not engage freely or if trouble has been experienced by 
 the driver with the gears not remaining in mesh, the trans- 
 mission case cover must be removed and the gears and 
 bearings examined. 
 
 Controls : 
 
 {a) Examine the change gear mechanism for wear and proper 
 lubrication. 
 
 Universal joints: 
 
 (a) Are all universal joints properly lubricated^ 
 
 (b) Are the dirt protectors in good condition? 
 
 (<?) '"Do any of the universal joints show signs of excessive wear { 
 Dift'erential : 
 
 {a) Examine the housing for cracks and oil leaks. 
 
 (b) Are all joints and bolts tight? 
 
 ( c) Is the truss rod tight ? 
 
 (d) *If the vehicle is worm drive, does the worm have excessive 
 
 end play (more than approximately ^c inch) ? 
 
 (e) "'"Does the dilferential function freely and smoothly? 
 
 (/) Is the lubrication of proper type and at proper height? 
 Examine some of the lubricants, drawn from the bottom 
 of the housing for metal chips. 
 
 Note.— -To test points marked ("') have one wlieel jacked up 
 and the other bhjcked. I'ut lower gear on mesh with clntcli engaged 
 and liave wlieel \\liicli is jacked up rotated forward and back- 
 ward. To test point marked (**) disengage clutch and proceed 
 as in (*) case except have wheel revolved tirst in one direction 
 and then in the other. 
 
 Shafts and chains : 
 
 (a) Do slip joints, if any, show excessive wear? 
 {b) Are all couplings tight? 
 
 (c) If previous trouble has been experienced with live axles 
 breaking, have the axles removed and examine for any 
 signs of twisting. 
 id) In case of chain drive trucks: 
 
 (d-l) Are chains properly adjusted^ 
 (c/-2) Are the sprockets badly worn or loose? 
 ((/-3) Do the chains show excessive Avear? 
 (//-I) Are the cliains p,roperly lubricated ? 
 
 V rCHICLE CONTROLS. 
 
 Steering gear: 
 
 (a) Is the wheel play excessive? 
 
 (b) Is the steering gear housing tightly bolted to the frame? 
 
 (c) Is the lubrication ample and proper? 
 Steering gear connections : 
 
 (a) Are the drag link spring ball joints properly adjusted, lu- 
 
 bricated and provided with covers? 
 
 (b) Are the steering connecting rod yoke pins and bushings 
 
 worn? Are they properly lubricated? 
 
 (c) Are the Avheels properly lined up? 
 
riELD ()^E^lATlu^'s. 93 
 
 Hand brakes: 
 
 {a) Aro tlic (Iruins ti^-lii on the \\lu'('l>, or if pntpcHcr >liaft 
 brake, is the (hum ti<rbt on the >liat't^ 
 
 (0) Do the brakes release fully ^ 
 
 (e) If a lined brake, is the lininj^" in need of renewal' If not 
 lined, aro shoes badly worn ^ 
 
 (//) If shoes are used do they J2;rip the diiiin proju'ily and aie 
 they properly centered^ Are the >hoe i)in-« free and lu- 
 brieated ^ 
 
 (( ) Does the e(jualizinn: meehanisni work pro[)erly and do 
 brakes grii) ecjually ^ 'Hiis fact can be best determined on 
 road test by obser\"in<>' rear wheels at time of sudden stops. 
 Positi\e «i:ripi)in(j: of one brake shoe will be reported with- 
 out fail, as this has a \ery harmful elfeet on the tire. 
 
 I/) Is the l)rake operatintj mechanism, cam, or to<rii:le Avorn ^ Is 
 it properly lubricated^ Are the operating shafts five and 
 well lubricated 'I Are the bushings worn ^ 
 
 (g) Are the rod yoke pins woin ^ Are they lubricated' 
 
 {h) Is the hand brake ratchet woi-n^ 
 
 (/) Are the releasing spiings in working orders 
 Foot brakes: 
 
 {") Are pedal shaft bushings worn ^ 
 
 FKONT AXLK. 
 
 IvnucUle bearings: 
 
 ( '/ ) .Vre the knuckle bearings or i)ushiug woi'u ^ if roller bear- 
 ings are used, is the adjustment cori'ect i 
 (h) Is the lubrication ample' Aic the lubricators broken or 
 lost^ 
 Wheel bearing adjustment: 
 
 (a) Are the bearings in good condition and is the adjustment 
 
 pro[)er? Roller bearings should have a small amount of 
 end play when cold in order to take care of expansion 
 from normal heating. The correct adjustment is to draw 
 the retainer nut up and then back oH' one-fourth of a turn 
 before setting the cotter. In order to test a bearing ad- 
 justment, the inspector must familiarize himself witli the 
 feel of a properly adjusted like bearing and jndge by 
 compai-ison. On the heavier trucks it will be nei essary to 
 jack up the wheel to make final decision. 
 
 (h) Is the lubrication ample? 
 
 {c) Are both hiii) caps tight i 
 Springs: 
 
 (o) Are there any broken leaves? 
 
 (b) Are any clii)s bi-oken or missing? 
 (r) Are the shackle i)ins or eyes worn i 
 
 (f/) Are the shackles well bibiicatecH Are any lubricators 
 
 missing? 
 (e) Are the springs rusted between leaves? 
 (/■) Are the springs to axle bolt< tiirht? 
 
94 TENTATIVK MANUAL CV INSTRUCTION. 
 
 REAR AXLE. 
 
 Wheel beaiiiii!' iKljiistiiieiit : 
 
 {(/), (h), (r), same as (a), {/>), (e) under "Wheel bearino- ad- 
 justment," aboA'e. 
 
 (d) Is tlie lubricant from wlieel bearino- leakino- onto the 
 
 brakes '( 
 Torque arm : 
 
 (o) If the tonpie arm has a bearings: at the rear, is it worn; is 
 it free or frozen; is it well lubricated? If it has no bear- 
 ing at rear end. is the means of fastening- it on the rear 
 axle housino- tight i 
 
 (J>) Is the front end support mechanism worn? Is it lubri- 
 cated? If a spring- mechanism is used at the front, are 
 the springs properly adjusted? 
 
 {(■) Does the tor(|ue ai'ni shoAv any ci'acks developing or loose 
 rivets, etc.? 
 Distance rods: 
 
 (a) Are the bushings at either end frozen or worn? 
 
 (l>) Are they well lubricated at both ends? Are any lubri- 
 cators missing? 
 Sprinfis : 
 
 (^V). (/>), (c), (d). (e), same a^ (a), (h), (r). {d). (<') under 
 " Springs,'' above. 
 
 (/') If the spring chair is bushed on the rear axle housing, is it 
 frozen ? Is the lubrication proper? Has the spring chair 
 developed any cracks? 
 
 ((/) Are the bolts holding down the springs tight? 
 
 (h) If provided with center pins are they sheared off? 
 
 ( /) If provided with center band, is it cracked? 
 
 TIRES AND WHEELS. 
 
 Tires : 
 
 (a) Do tires need replacement? 
 
 (h) Are they loose on the wheels? 
 
 (r) If ]uieumatic. are they ])roperly inflated? 
 
 (r/) If solid, condition and appearance of cuts, runners, and 
 snipping. 
 
 (e) Do the tires show signs of excessive wear caused by wheels 
 
 being out of alignment or by under inflation? 
 
 (1) Are wheels in cood condition? 
 ■ (2) Spokes tight? ' 
 
 (3) Spokes cracked or broken? 
 
 (4) Hub bolts tight? 
 
 CHASSIS. 
 
 Frame : 
 
 (a) Is frame bent in any place ? 
 
 (h) If provided with a strut rod. is it tight? 
 
 (e) Are there any cracks deAeloi)ing (es])ecially al)out center) ? 
 Brackets : 
 
 (a) Are there any signs of fracture? 
 
 (l) Are all bolts or rivets, holding to tlie frame, tight ? 
 
FIELIi OPKHATIONS. 95 
 
 (ii) Arc rear hiiinpcrs. if prox idcd. in liood condition ;ind tiuiil 
 
 on traiiio t 
 (h) Are front Imnipcr s|)riM^> lirokfii ^ Arc mII |)art> tiiihtly 
 
 bolted and in g,oo(\ condition '. 
 [<■) Is lailiator ^iiard in <.'oi)d coiidiiion^ 
 Mud <i;iiard> : 
 
 (<i) Arc any liadly Ucnt. hroki-n. or niissinLT^ 
 
 (A) Are rivets or bolts fioni niiid <>iiar(l to bi-ackct> tiirbt '. Aie 
 
 bolts from biackets to frame tinht '. 
 J'ow in<>' hooks : 
 
 (u) Are liook> or spi-inii-- liroken' 
 (l>) Are I'astcninii'^ to frame lijiht^ 
 
 non^ . 
 Sca.t and dash : 
 
 {(t) Is the supcrsl ruiiurc >ccni-cly held lo the fi'anic ^ 
 
 {h) Are the seat and cushions in aood conditifui^ 
 
 (r) Is the dash bi'okcn or ci'acktMl i 
 
 {(1) Arc the lami) lirackcts ti<:ht '. 
 Top : 
 
 (<i) Is the seat top in ;rood condit ion ' 
 
 (h) Is the body tarpaulin sound and watcr-t iii'hl ' Is it coi- 
 rectlv lashed down '. 
 Body: 
 
 ((/) Arc the bolts and i)iackct> which hold the body to liic chassis 
 broken or loose. 
 
 {h) Is the tail ^ate broken^ Are any tail ^ati' chains uii>-in^ 
 or broken ? 
 
 (c) Are any body chains broken ? 
 
 {(1) Does body need any cari)enter Avork? 
 
 {e) Is the tool box in jiood condition? 
 
 (/) Arc tlie troop benches in <i:ood condition? 
 
 {(/) Is the inside of the body clean ? 
 
 EQUIPMENT. 
 
 Tools: 
 
 (a) Any shortage against standard list ? 
 
 (&) General condition of tools'? 
 
 {a\ Any shortaae against standard list? 
 
 {h) General condilion of accessories? 
 Accessories : 
 
 SPECIAL NOTES. 
 
 In making out inspection report, enter under " IJemarks "" any 
 points not covered in the body of the report. The outline of j)oint> 
 to be inspected, given above, is intended as a guide and does not 
 necessarily cover all points Avhich may come u|> at in.-pection. 
 
 (iKNKl.'AI. ( (iNDI I IONS. 
 
 Under **(ieneral condition" the inspector will enter a statement 
 c(»ncerning tlie \ehicle as a whole and any couiments which he thitdi-- 
 ad\isablc to note conccining t he way it is carc<l i'oi- and opcratccl. 
 
96 TENTATIVE MANUAL OE INSTRUCTION. 
 
 RATE SYMBOL. 
 
 The same symbol as entered on the inspection chart will be placed 
 very plainly in the lower left-hand corner of the inspection report. 
 It is very important that this be done and that the instructions on 
 sample instruction chart be followed for determining the symbol to 
 be used. 
 
 The driver will enter in the Log Book of the vehicle the date in- 
 spection was made and the rate symbol, and sign the same. 
 
MOTOR TRANSPORT CORPS 
 R. O. T. C. UNIT 
 
 CONVOY PRACTICE 
 OUTLINES 
 
 130647—19 7 97 
 
SCHEDULE OF CONVOY EXERCISES. 
 
 GKN KliAIi STATEMENT. 
 
 Tlu> following exercises in "Convoy" presiijipose that the students 
 •ail' able to drive the vehicles with reasonable facility. 
 
 The instructor should ascertain, by road trial, which students are 
 able to drive, and take steps to provide instruction in clementaiy 
 drivino; for the otlier students, far en()U<rh in ad\ance of the regular 
 convoy instruction to have all students able to drive befoi-e the con- 
 voy exercises stait. 
 
 FlKSr EXERCISK. 
 
 Stationary field drill illustrating distances and formations. 
 
 ^^ethod of crardving motors with left arm. 
 
 Position of driver and assistant driver. 
 
 Space trucks to illustrate distance between ti'ucks and sections in 
 open and close foi'mation. Have men sight on souie part of truck 
 ahead to use as gauge for proper distance. Exjjlain about getting 
 distance from truck ahead and speed from truck behind. 
 
 Give and practice signals for attention, crank motors forward and 
 halt. ' "^'jv , 
 
 Go through drill of assistant drivers coming to atteiifion upon 
 liearing whistle signal and insist that they all jump from their seats 
 at the same time and land on the ground in their projx'r positions 
 sinudtaneously and in a uniform nuinner. 
 
 Outline positions of truckmastei- and assistant truckmasters. Ex- 
 plain wheie the Iruckmaster and assistant truckmasters ride. 
 
 Inspection of equipment preparatory to road exercises. 
 
 KeftM-ences : Teiitativi' M.iniial of Inslniction. .M. T. ('. I{. ^^. T. (". I'liit. Field 
 Olierations I.oitnr*' : 
 ■■ Siiriials and Koad Unit's" .NO. \'. 
 
 Skcom) Kxkhcisk. 
 
 Trucks on road oi)erating in sections. 
 
 ( )bsei've distances and speeds in open and closed formation. 
 Instruct in general road rules and enforce tlieir observance. 
 Exercise thoroughly in use of signals. 
 
 Exercises in crossing bridges, placing of guards at crossroads, 
 raili'oad tracks, etc. 
 
 Ijlu'-trate the handling of road repairs and disabled e(iuipment. 
 
 09 
 
100 TENTATIVE MANUAL OF INSTRUCTION. 
 
 Method of righting overturned truck by use of block and tackle. 
 Extracting truck from mud, etc. 
 
 On return to park, explain parking system and see that trucks are 
 placed in position, properly spaced, and in line. 
 
 Exercise in knots to be used for tOAving, temporar}^ repairs, etc. 
 
 Keferences : Tentative Manual of Instruction. M. T. C. R. O. T. C. Unit. Field 
 Operations Lecture : 
 " Signals and Itoad Rules "' No. V ; " (Jeneral I'rini'i]iles of Convoy " 
 No. Ill: " Knotlins and Splicing" No. IX. 
 
 . THIHD EXEHCISE. 
 
 Trucks operating in company formation. 
 
 Exercise in maintaining proper speeds and intervals between sec- 
 tions in both open and closed formation. 
 
 Instruction in all signals and insist on uniformity and correct 
 manner of giving signals as well as executing them. 
 
 Exercise in reversing convoy (caution against allowing rear 
 wheels to leave firm, hard ground and illustrate what hapi^ens if 
 they do). 
 
 Exercise in handling individual truck by hand signals. Do not 
 allow verbal signals to be used during this exercise. Have trucks 
 backed up to platform or an assumed place to unload. 
 
 References : Tentative Manual of Instruction, M. T. G. R. O. T. C. Unit Field 
 Operations Lecture : 
 " Signals and Road Rules " No. V. 
 
 FOURTH EXERCISE. 
 
 Trucks in company formation. 
 
 Night operations with and without lights in open and closed foi'- 
 mation. 
 
 Exercise in whistle and verbal signals. 
 
 Caution men in halting trucks to avoid colliding witli trucks 
 ahead. 
 
 Explain use of white squares on back of trucks. 
 
 Insist on convoy moving sloAvly until drivers aie confident of 
 ability to handle trucks in dark. 
 
 References: Tentative Manual of Instruction, M. T. C. R. O. T. C. Unit. Field 
 Operations Lecture : 
 " Signals and Road Rules " No. V. 
 
 FIFTH EXERCISE. 
 
 Trucks in company formation. 
 
 Field problem in map reading, including exercises in location, 
 orientation, reading compass, calling attention to influence of large 
 mass of metal on needle of compass. 
 
 Exercise in loading and unloading troops and materials. 
 
 In loading and unloading troops emphasize assistant driver's re- 
 sponsibility for men in getting them to the ti'uck. 
 
 Exercise in maneuvering men into formation necessary for load- 
 ing troops, following diagrams given in Manual. 
 
CONVOY PRACTICE OUTLINES. 101 
 
 Kxt'icisc in iiiati'ii;il lojuliiii:-. ItiicUinjj: trucks to loiiding platforms, 
 
 Di.-tril)iitioii of loiul.^ with n'<::u(l to wci^-ht. 
 
 Seen ring of loads. 
 
 Exercise in use of correct iuiot^ for seciirin^i- loiuls. 
 
 Kt'fereiices : Tentative Manual of Iiisi iiul inn. M. T. « ". K. «). T. C. I'nit, Field 
 Operations Lectures : 
 "Mail Ueadinir" No. VI: " Loailinu' " No. VII; '• Knotting and 
 Splioinjc; " No. IX. 
 
 si.xTii i:.\i:i!( isK. 
 
 (leiKM'al review and iicid prol>l('in. 
 
 Furnish men with wiitien orders an<l maps and allow them to 
 execute instrut-tions with as little a.ssistance from instructor as 
 necessarv. 
 
 P^xplain and correct any mistakes made. 
 
 (irivL* opportunity for all men to act in executive capacity. 
 
 Koferonces: Tentative Manual of Instruction, M. T. C. R. O. T. C. Unit, Field 
 Operations Lecture : 
 '• Convoy Problem '' No. VIII. 
 
 SEVENTH EXEIJCISK. 
 
 Trucks in company fornuition in park. 
 
 Exerci.se in method of washino: and cleaning equipment, also 
 oiling and greasing. 
 
 Fornuition for formal inspection illustrating position of men an<l 
 arrangement of equipment. 
 
 Formal inspection. 
 
 References: Tentative Manual of Inslrudion. M. T. C. K. O. T. C. Unit, Field 
 Operations Lecture : 
 "Care of Equipment" No. IV. 
 
MOTOR TRANSPORT CORPS 
 
 R. O. T. C. UNIT 
 
 ELEMENTARY AUTOMOTIVE ENGINEERING 
 LECTURES. 
 
 103 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LECTURE I. 
 THE GASOLINE ENGINE. 
 
 (Instniotioii Clinrts Xds. 1, l', 3, 4, ."., Ci, 7, s. ft. T>. iMiuipnuMit : Dodj:*', Wliius 
 
 Ciulilliic motors.) 
 
 Tlif cMio:iiie of a gaj^oline vehicle is the power plant, and wliile it 
 could not opei'ate without the aid of additional appliances such as 
 the fuel system, the ignition system and cooling system, it is very 
 imp<jrtant that it lie thoroughly understood. First, as to principles; 
 and, second, as to t^'pes. 
 
 The term '" gas engine " is u.sually used to designate the internal 
 comhustion engine without regard to whether it operates with gas 
 or liquid fuel. The purpose of all engines is to convert the heat^ 
 generated l)y the comhustion of the fuel, into worl'. Existing engines 
 may be divided into two classes according as the combustion takes 
 ]>lace outside or inside the working cylinder. 
 
 In the first-nanie(l class, the heat of combustion is transmitted l)y 
 conduction extei-nally lo a woiking medium which carries the heat 
 into the cylinder and is there transformed into work. The most 
 common example of this class in the steam engine; another example, 
 tliougii in limited uses, is the hot-air engine. 
 
 In the second class, the fuel is introduced into the cylinder in the 
 foiin <d' an explosive mixture, and tlune is ignited; the heat gen- 
 erate<l by the combustion is transformed into work, acting diivctly 
 on the piston — hence the name '' internal combustion engine.'' 
 
 The tei-m "cycle," as applieil to an engine, may be defined as a 
 r^eries of events which are repeated in regular order, constituting the 
 piincii)le of operation. These several events comprise the transfor- 
 mations which take |)lace in the working medium, or, with reference 
 to the gas engine, the distribution and l)ehavior of the fuel mixture 
 in passing through the engine. 
 
 'ihe gas engine derives its energy from (he heat, generated by the 
 combustion within the cylinder, of a mixture of fuel in the form of a 
 gas, or spray, mixed with aii- in the propi'r proportion to form an 
 explosive mixture. 
 
 The mixture is admitted to the engine intermittently, and the 
 amount supplied at each admission is known as the charge. The 
 combustion of each charge takes place under pressure attained by 
 c<»nipression — a result of the inward movement of the piston after 
 the charge is admitted ai\d all valves closed. 
 
 10-> 
 
106 TENTATIVK MANUAL OF INSTRUCTION. 
 
 The etiVct ])i'()(hK'e(l l)y i,iiiiitiii<>' the mixture after compression is- 
 commonly called an explosion, which is simpl}' a quick burning of 
 the mixturi'. This sudden explosion causes a high degree of heat 
 within the combustion chamber, I'esnlting in considerable initial pres- 
 sure, and gives to the piston an impulse, which decreases in intensity 
 as the piston advances to make the power stroke, by reason of the 
 ex[)ansion of the gases. The ])i-oducts -of combustion are finally 
 exhausted from the cylinder through the exhaust A'alves. 
 
 P^xpressed briefly, the working operaticm of a gas engine embraces: 
 (1) the aduiission of th.e charge into the cylinclei-; {'2) its c;;m[)res- 
 si(vn; (8) ignition, combustion and expansion ; and (4) the subsiMpu'ni 
 exhaust of the products of combustion. 
 
 In the o[)eration of a gas engine, the number of strokes reiniired to 
 complete tlie cycle vai'ies with the type of engine. For autouiobile 
 l)i'opulsion, the cycle is usually extended through four strokes, 
 although in a few iiihtarcj's it is coiupleted in two strokes. Engine^ 
 of these types are known :!s four-stroke-cycle, and two-stroke-cycle. 
 respecti\ely. 
 
 The four-stroke cycle or more conmioidy called the four-cycle en- 
 gine, although move bulky than the two-cycle engine, and re(}uiring. 
 u])proxiuuitely, tv/ice the number of cylinders for etpuil turning 
 effect, is almost universally u; ed for pro]nilsion of automobiles; it 
 has advantages over the two-cycle engine, which have more than 
 offset its undesirable feature, and caused it to come into general 
 faA'or. Among the advantages which may be mentioned are : effi- 
 ciency, flexibility, adequate admission of charge at high speeds, higher 
 degrees of expansion, and more efficient exhaust. There are four 
 strokes comprising tl^e vrnrking cycle of the four-cycle gas engine: 
 (1) the intake, ('i) coin})ressi()n, (?>) ]:>ower. and (4) exhaust stroke^. 
 
 F( > I US THOKIX ■ Yf LP: EN (.1 N E. 
 
 In defining the [)i-i!iciples of four-cycle motor action, one can 
 explain the matter very clearly by comparing the effect produced by 
 exploding gasoline gas to that which obtains when one explodes gun- 
 })ow(ler in a gun, for example in an old pattern muzzle-loading can- 
 non. Consiclering the first ])henomenon which obtains when gun- 
 l)owder is burned, one can obtain some idea of how exploded gasoline 
 vapor may be transfornr-nl into power. In fact, the preliminary 
 operations which have heen necessary before the gun was fired, are 
 very similar to those which precede an explosion in the cylinder of 
 the gasoline engine of the four-cycle type. Following first, the 
 cycle of operations necessary to fire the cannon, it will le seen that 
 a certain se(juence is necessary. AVe have the loading, or charging 
 of the gun. The powder which is carried in bags for convenience, is 
 introduced in the muzzle and pushed back into the breech with the 
 lamrod. After the poAvder has been compressed the ball is placed 
 and tightly lannned in i)lace on top of the powder in the explosion 
 chamber. After the jiowder is properly compacted, it is exploded by 
 means of a lighted fuse, or percussion cap, and the cannon ball is 
 forced out through the open end because of the pressure of gas on 
 its underside, this ha\ ing l;een j)ro(luced l)y the rapid burning of the 
 powder. 
 
ELEM ENTAH ^■ A VTi ) .M ( )T I \K K NCI X K i;i; IXC LIU 'T \ ' RES. 
 
 107 
 
 The w\t operation is clcaiiiii; the i:im of the Imined «rases in 
 order to introchiee a fresh c-hari»:e of powiU'r and shot. The clearinir 
 is automatically perfonne<l. As soon as the hall leaves tlu' niontli 
 of the nioi'tai- the «ias which is still nndei- hiu'h press\ire escapes to tlie 
 atmospliere. Aftei- the bore is sponpMl out. one can introduce an- 
 other charjie and Hre the cannon airaiu. Die powi'r to pi'opid the 
 sjiot thi"(!U<:h the ail' has heen (»litaineil l)y l)urnin<:' a sul)^t;ince whicji 
 hefore ignition had no powei- to pro(luce motion of the hall. If an 
 i'(|nal char<ie of jiunpowdei" had l)een placed in the open air and the 
 shot |)laced upon it, if the conihustihle material weic ignited, thei-e 
 would i'e \erv lillle ('ner<ry jjrodnced. There woidd he u !l;i>h of 
 tianie. hut it isdouhtfid if this would ha\i' pidduced sutHcient enerjiy 
 to cause the cannon hall to lea\"e its jxisition. Powdi'r t'onipacted in 
 the cannon hai'r(d pi-oduce<l usefid enemy hi'cau^e pressure* was con- 
 fined in a chami)er having ri<iid walK ;tt all sides, except one. this 
 1 ein<:' the side of the cannon hall neai't'st the e.\i)losive Tlie metal 
 surroundin<r the explosion chamber had suH<ci( nt siren<i;th 1o resist 
 the hi<;h «fas pressure, but the ball which wa-. movable, was di-i\i'n 
 out lecause its weiaht was not >ul1icient lo icsist t)ie foi\ (> a])plied 
 to it by the I'xplodinu' jjowdi'i". 
 
 The modern <j:a.s(dine en<iine follows the action of the olt|-ty|)e 
 mu/zle loadei'. A\'e can compare the action of the simple four-st'oke 
 en<>;ine with that of a cannon. The principal elements of a jjas 
 enfrine are not dillicult to understand and their functi<ms are easily 
 defined. In place of ll\e barrel of the <.inn, there is a smoothly nui- 
 cidned cylinder with a small cylindrical, or barrel, shaped element 
 fittin<i" the boic clo-ely which may be likened to ;i t-annon b:dl. 
 It dirt'er> in thi> important resi)ect. however, that while the shot is 
 dischar<i-ed from the month of the cannon, the piston membei' slidinu' 
 in-'ide of the main cylinder can not leave it. as its movements back 
 and forth from the open to the closi'd end and back a<>ain are limited 
 by a >imple mechanical connection, or linkage, comprised of craid\ 
 and connection rod. Tt is by this means that the reci|)rocatin<r 
 movement (d" the piston i> tr;in>foiiu('d into a rotary motion of the 
 craidv shaft. 
 
 I)urin<i: the auction sti'oke the pi>ton moves outward autl draws in 
 a charge of the fuel mixture. The following inw:ii<l -stroke com- 
 j>resses the charge into the combustion chamber: at the end of this 
 -troke the charge is ignited, causing a rapid rise of ))ressni-e. and sub- 
 -e(|Uenl expansion of the protlncts of i-ombu>tion during the next, or 
 powei- stroke. > The expanded gases ai'e exjxdled fiom tlie cylinder 
 during the return, or exhaust stroke of the piston. 
 
 The first and thii'd aiv outward, and the second and fourth inward, 
 that is. the piston moves away from the combustion chambei- during 
 adnnssion and impulse, and ai)proat-hes it during compression and 
 exhaust, and the piston I'eciMves an impidse once in exciy two icvo- 
 lutions 
 
 II I oils. 
 
 The action of the valves during the cycle i>: Duiing adnn-^sion. the 
 inlet valve remains open, and the exhaust \alve closed; duriuir the 
 compression and power strokes, both valves remain clo.sed : exhaust 
 takes jdace with the inlet valve closed, and exhaust open, and the 
 ignition takes place at a variable time, near the end of the com- 
 ])rossion sti-oke. depending upon the speed and load, so th(M-e will be 
 
108 TENTATIVE MANUAL OF INSTRUCTION. 
 
 time for the pressure due to conibiLstioii to build up and thus secure 
 a higli initial pressure at the beginning of the power stroke. The 
 heavy flywlieel receives sufficient monientuni during the power stroke 
 to keep the engine going at approximately uniform speed during the 
 period between impulses. 
 
 The weight and size of the flywheel must be considerable on ac- 
 count of the prolonged pauses between impulses; by reason also of 
 the large-size piston necessary, there is considerable vibration. This 
 is overcome by the use of several small cylinders, in place of a single 
 one of large size, and this arrangement is called a multi-cylinder 
 engine. 
 
 There are usually four or six cylinders in tlie medium and large 
 sized vehicles; for those of small size there are sometimes only two, 
 and in rare instances one. The action of a multi-cylinder engine 
 in overcoming the objection to a single cylinder is that the heavy 
 impulse of the single-cylinder engine may be divided into several 
 small impulses by working a number of small pistons from one shaft. 
 In order to reduce vibration and secure a better turning effect the 
 cranks are so placed that the several impulses occur at different 
 times. A small fl^'wheel then suffices to secure approximately uni- 
 form rotation. 
 
 The efficiency of a gas engine is the proportion of heat turned into 
 work as compared Avith the total heat produced by combustion. This 
 does not represent the actual efficiency of an engine on account of 
 various losses in operation which cause the actual or mechanical 
 efficiency to be less than the thermal or theoretical efficiency as 
 defined above. 
 
 With the cycle extended to four strokes, there is more time for ad- 
 mission and exhaust, and since these events take place at separable 
 intervals, no chance is given for an}^ of the charge to escape past the 
 exhaust valve while open. 
 
 TW'O-STROKE CTCLE ENGINE. 
 
 The two-cycle engine is used, to a limited extent, for auto- 
 mobiles; the essential difference between it and the four-cycle type 
 is that the four operations of admission, compression, impulse, and 
 exhaust, comprising the working cycle, are performed in one revo- 
 lution instead of tw^o. There is, then, one impulse for each revolu- 
 tion. From this, it folloAvs that the weight is much less than that 
 required for the four-cycle engine. The necessary mechanical fea- 
 tures for two-cycle operations are as follows : 
 
 1. An inclosed crank case fitted with a valve arranged to open and 
 admit fuel mixture at the front of the piston, on the inward stroke. 
 
 2. Inlet and exhaust poi-ts so located that they will be uncovered 
 during the outward stroke. 
 
 3. A bj^-pass tube connecting the interior of the cylinder with the 
 crank case, so as to admit the charge at the proper point in the cycle. 
 
 During the first stroke the piston moves inward and draws in a 
 charge of the explosive mixture into the enclosed crank case : during 
 this operation the charge previously admitted to the cylinder is com- 
 pressed and ignited as the piston nears the end of the stroke. 
 
 During the second stroke the pressure caused by the explosion of 
 the charge drives the piston outward, and slightly compresses the 
 
KLE.MEXTARV AUTOMOTIVE ENGINEEHING LECTURES. 109 
 
 mixture drawn into the crank ca.se (lurin<j: tlio previous stroke. Near 
 the end of this stroke the ])iston uneovei's the exhau.st port and the 
 burnt liases arc exhausted. Duiinc: thi' leniainder of the stroke the 
 pistoii uncovers tiie achnission jxjrt, and (he new charge, previously 
 compressed in the crank (Mise, is aihnitted to the cylinder, bcinjj de- 
 ilccted upwai'd to the head end of the cylinder l)y a screen or "'de- 
 flector ]>late" on the end of the piston. The "inrush" of the new 
 chaige helps materially to clear the cylinder of the hurnt gases from 
 the previous charge. The object of the deflector j^late is to prevent 
 the entering charge passing out through the exhaust with the burnt 
 gases. 
 
 The two-cycle engine has the atlvanlage over the four-cycle engine 
 of less weight and the absence of poi)p('l valves willi their springs, 
 stems, ])ush rods, and cam shafts, thus ejecting a more sim])le con- 
 .struction. Since the frequency of impulses is gi-eater, a better turn- 
 ing eiTect is secured. The inefficiency of admission and exhaust of 
 the two-cycle engine becomes more marked at high speeds. The four- 
 cycle engine gives better fuel economy than the two-cycle engine. 
 
 NOMENCLATURE. 
 
 A gas engine is composed of stationary and working j^arts, i. e. : 
 The stationary parts are: (1) The cylinder, and ("2) crank case; the 
 working parts are: (1) The piston, (2) connecting rod, (3) crank 
 shaft, (4) fly wheel, and (6) valve mechanism. 
 
 THE CFLINDER. 
 
 The cylinder of a gas engine is open at the end toward the crank, 
 and closed at the opposite end, save for inlet and exhaust ports, 
 which are opened and closed by valves. The cylinder is supported 
 by the crank case, made up of an intermediate piece to which the 
 cylinder is attached and a lower piece which retains the oil. 
 
 COMBUSTION CHAMBER. 
 
 The combustion chamber corres])onds to the clearance sjiace in a 
 steam engine, but its object is to jirovide a small sj^ace into which each 
 charge of the fuel mixture may be compressed to considerable pres- 
 sure, on the compression stroke of the piston, and then ignited. It is 
 sometimes called clearance. 
 
 THE PISTON 
 
 The piston is a cylindrical box of proper size to slide back and 
 forth in the cylinder bore and is of the tyjie known as " truidv piston." 
 The piston is single acting — that is, it is acted upon by power on tlu^ 
 face only. To prevent leakage several grooves are cut in its cii'cum- 
 ference to receive packing rings, the type generally used being known 
 as " snap rings." 
 
 The u))per end of the connecting rod is pivoted to a "wrist pin." 
 which is inserted in the i^iston through a hole boi-ed through its cen- 
 tral diameter. The wrist pin is retained in place by one or two 
 set screws. 
 
110 TENTATIVE MANUAL OF INSTRUCTION. 
 
 CONNECTING KOI). 
 
 The connecting rod transfoi-nis the to and fro motion of the piston 
 into rotary motion and transmits the thrust or power impulse of the 
 piston to the crank shaft. The connecting rod is usually of rectan- 
 gular or I-shaped construction and has an adjustahle bearing at each 
 end. One end is pivoted to the piston by the wrist pin, and the 
 other end to the crank shaft by the crank pin. 
 
 CRANK SHAFT. 
 
 The crank shaft is formed from a solid steel forging and consi.-ts 
 of a central cylindrical piece, from which radiate one or more cranks, 
 corresponding to the num])er of connecting rods. 
 
 FLYWHEEL. 
 
 On the end of the ciank shaft is a heavy flywheel which receives 
 sufficient momentmu during the power stroke to keep the engine 
 going at ai)i)roximately uniform si)eed dui'ing the period between 
 impulses, and assists in balancing the engine. 
 
 VALVE GEAR. 
 
 Each cylinder must have one inlet and one exhaust valve usually of 
 the type which are called poppet or mushroom valves. These con- 
 sist of metal disks beveled around one face, so as to fit into a counter- 
 sink in the port and they are carried upon spindles. The stem or 
 spindle is made of sufficient length to extend down into the crank 
 case; it enters through a bushing, Avhich serves as a guide. Attached 
 to the end of the stem is a roller bearing, or follower, wdiich rides on 
 a cam, attached to the cam shaft, which is geared to the crank shaft 
 in such proportion that it makes one revolution to every two of the 
 crank shaft. By means of a spring the roller bearing, or follower, 
 is held in contact with the cam. Valves may be operated from a 
 single cam shaft when they are located on one side of the cylinder; 
 when the valves are on opposite sides, two cam shafts are necessary. 
 
 PISTON RINGS. 
 
 Piston rings are made from a pipe-shaped casting, which is turned 
 in a lathe to an outer diameter slightly larger than the cylinder. 
 The inner circumference is then turned from anoth-er center, and the 
 ring cut off and si)lit at the thinnest section. Enough metal is re- 
 moved at the split section so that the ring may be slightly compressed 
 and again turned externally to the diameter of the cylinder while 
 compressed. The latter operation causes the ring to bear evenly 
 against the cylinder walls, thus making a tight joint. Althoiigh 
 formed of a brittle substance, piston rings have considerable elas- 
 ticity, being capable of opening suffii-iently to slide over the outer 
 diameter of the piston, and to "' sua]) " back into the grooves. 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LECTURE II. 
 
 TYPES OF MOTORS. 
 
 H Insi lUitioM t'h.iits .Ntis. 4, '}. G, 7. EquijtuiiMil : l><Mly;f, ( ';i(lill;ic. .iiiil Kikci' 
 
 motors. ) 
 
 'ilu' cylindi'r of a jLTiisoliiu' cnjiiiu' i> iiiadc ( f rust iron or 20 \ivi 
 rent scnii.sti'cl, and tlu' water jackets aic <i'enerally cast i)i one i)iece 
 with it. Tlie cyliiulers of an eno'ine with more than one cvlindcr 
 are either cast sin^zly. in pairs, or en l)loc. 
 
 The i)ortion of the cylincU'r in which the i)i>ton nio\e> shonhl l»e 
 a true circle and as smooth a> |)o>sihle. In the bettci' <rra(K' of i'ar>: 
 llu' cylinder walls are around to a smooth finish so that tiicre may 
 he as li'itle fri(tion as possil)le. Any rouuhness of the walls will 
 can.-e wear, which I'omos in the form of cut^ and scratches length- 
 ways, tiuit i)ermit the i)ressure to escape around the piston. 
 
 .'v motor is called either an '" L,""' "T." or "valve-in-head" (the 
 hitter also Idiead): this name is <jiven ace'erdin<>- to the de.-ian ot 
 the cylinder i)lock looking at the' end. 
 
 The ■" r " head ty|)e of cylinder is made >o that the I'xhaust \alve.s 
 are on oni' side and the inlet \alves are on the other side. The " L" 
 head type of cylinder is made so that the exhaust and iidet val\e> 
 are all (.n one side of the cylinder. The \ ah e-in-head <ylinder has 
 all the \alves in the toj) of the cylinder. 
 
 In the ■■ \' *■ type en<j^ine of eight (vliiulers ihey are iiroupcd in 
 -^ets of f( ur. which are placed i)() decrees apart, and on a twin-six 
 I'vlinder en<:ine the two sets oi six are tW) deorees ai)art. ("ylinder> 
 may he cast solid or with delachahle head. The detac-hahle head is 
 i.aininji: in favor. It permits easy access to the val\"es to remove 
 carhon oi- to remo\e pistons, and is (jood manufacturinu- practice he- 
 canse it nnd<es the <Jrindin<> of the cylinders easiei'. 
 
 The following cjuv aie made with detachable heads and are cast 
 en 1>1(«-: Dod.iie. White, Standaidi/.ed " I^" (J. M. ('. Model IC. and 
 V adillac. 
 
 iioijsK-i'ow Ki! nKrr.it.M i \ a i kin. 
 
 .V foot-i)ound is the amount of work expended in rai>in<:' a weiohl 
 of 1 |)ound 1 foot, or in ox'ercomini:- a pressure of 1 pound thi<>u<rh 
 a distance of 1 foot. 
 
 INwer is the i-ate at which wcirk is done. It i- the (|Uolien1 of 
 woi-k dixided by the time in which it i> done, thus: 
 
 ■I, AVork pouuti- '^distance 
 
 J ()wer= . or ' 
 
 tnne muiutes. 
 
 Ill 
 
112 TENTATIVE MAXUAL OF INSTRUCTION. 
 
 One horsepower is 33,000 foot-pounds of work done in one min- 
 ute. Tliere are several factors on which the horsepower of a gas 
 engine depends: (1) The mean etfective pressure on the piston (in 
 pounds per square inch), (2) the area of the piston (in square 
 inches), (3) the stroke (in feet), and (4) the number of power 
 strokes per minute. The product of these factors divided by 33.000 
 Avill give the indicated horsepower. This does not take into account 
 the friction of the engine, which may amount to 10 per cent, or more. 
 
 Bi-ake horsepower is the actual power delivered to the shaft, as 
 determined by making a brake test. It is equivalent to the indicated 
 horsepower less the power absorbed by the friction of the engine. 
 
 The pressure within a gas-engine cylinder during the suction stroke 
 is about 1 pound less than the pressure of the atmosphere, on ac- 
 count of a certain degree of suction, or ])ressure reduction, necessary 
 to overcome the frictional resistance encountered by the incoming 
 charge as it flows through the inlet manifold and passages. 
 
 The velocity of the mixture flowing through the valves in a well- 
 designed engine is from 4,000 to 5.000 feet per minute. The pressure 
 of the atmosphere is about 14.7 pounds absolute, at sea level, that is, 
 14.7 pounds measured from the zero of a perfect vacuum. This is 
 equal to zero pressure as measured on a steam gauge, which usually 
 only measures pressures above the atmosphere. 
 
 The ignition occurs in the combustion chamber before the end of 
 the compression stroke because combustion requires time; if the com- 
 bustion begins at the proper instant before the completion 
 of the compression stroke, the maxinunn pressure will be attained 
 at the beginning of the power stroke. This is desirable (1) 
 to avoid loss of power and (2) to insure sufficient reduction of 
 the temperature of the gases at the opening of the exhaust valve to 
 prevent injury to the latter. 
 
 At or near the beginning of the power stroke the maximum pres- 
 sure of 350 pounds within the cylinder, due to combustion,is reached ; 
 the temperature at this point is excessive, being 2,000° F., or even more. 
 As the piston advances, the gases expand, and both pressure and 
 temperature fall; near the end of the stroke, the exhaust valve opens 
 and the pressure at this point di'ops almost to that of the atmosphere. 
 This operation is possible with such high tenrperature as 2,000°F., 
 as the combustion chamber and cylinder are surrounded with a jacket 
 through which cooling water circulates. This prevents the temper- 
 ature of the cylinder walls and w^orking parts rising beyond their 
 r>roper limits. 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 LECTURE III. 
 
 TIMING AND BALANCING. 
 
 ( Inst met ion ("liiirts Nos. H. ;{, 4. f), (5, 7, N. 80, 32. K(Hiii)iii<'iii ; Itodp', < 'iidillar. 
 
 and White motors:) 
 
 The system oi- process by means of which tlie moment ol" ignition 
 and the opening and closing of the valves is reguhited in an internal- 
 combnstion engine is called "* timing." The timing of the valves is 
 an expression analogons to " valve setting'' in regard to a steam en- 
 
 Balancing involves some mechanical means for rendering all move- 
 ments ])erfectly even and for neutializing thrusts and vibration; con- 
 siderable ingenuity has been exercised in the effort to achieve a per- 
 fect solution. A single-cylinder engine is balanced by fastening 
 counterweights on the opposite side oi the crank, while in a two-cylin- 
 der engine the cranks are often placed opposite each other. This 
 mechanically balances the engine, but the explosions will take place 
 at irregular intervals and thus cause the engine to vibrate. In some 
 engines both cranks are set the same way, and counterweights are at- 
 tached as in a single-cylinder engine. The explosions in such engines 
 take place at regular intervals, but in practice it is found that such 
 engines vibrate more than the former kind or account of very poor me- 
 chanical balance. 
 
 It is not possible to perfectly balance an engine by counterweights: 
 an engine may be balanced by counterweights to run at a certain 
 speed with no perceptible vibration, but a variation below^ or above 
 this speed will thrown it out of balance. The arrangement of the 
 cranks of a multicylinder engine produces a mechanical balancing 
 effect in itself, but in order to reduce the vibration to a minimum, 
 timing of the explosions in the various cylinders is necessary. 
 
 The timing of the valves is effected by arranging the cams which 
 operate the valves so that successive firing cylinders are on opposing 
 cranks. Manufacturers ordinarily express the rotation of firing as 
 the engine fires 1, 2, 4, 3, or it fires cylinder 1, then 3, tlien 
 4, and then 2. The adjustment of the ignition mechanism must 
 follow the same rotation as governed by the cam rotation, in order to 
 govern the firing so far as balance is concerned. In ascertaining the 
 method of the timing, as regards the firing of the successive cylinders^ 
 the engine should be turned over slowly by hand. By watching the 
 lifting of the inlet or exhaust valve stems, the point of ignition will 
 come about one-half turn after the seating of the inlet valve on each 
 cylinder. The timing device governs the ignition. To adjust the 
 timer the engine should be turned slowly until the inlet valve of 
 
 130r.47— 10 8 m 
 
114 TENTATIVE MANUAL OF INSTRUCTION. 
 
 cylinder Xo. 1 seats. It is then given an additional half turn; if the 
 timer be fastened ta the cam shaft by a set screw, the latter may be 
 loosened and turned around until contact is made with one of the 
 points and the set screw tightened. The wire leading to spark coil No. 
 1 is connected to this. terminal and the secondary wire of this coil to 
 spark plug (m cylinder No. 1. The engine is now slowly given another 
 half turn, during which it should be noted which inlet valve seats: 
 it .should be that of cylinder No. 2 or No. 3. The primary wire of the 
 second spark coil is connected to the binding screw of the timer point 
 now in contact, and the secondary wire of this coil to the cylinder 
 which has been found to be in action. The remaining cylinders are 
 then connected up by similar procedure. 
 
 The dead center of an engine may be determined as follows: At 
 some easily accessible place near the rim of the flywheel a pointer 
 is fastened to the frame of the engine. At the top of each cylinder 
 there is usually a plug or pet cock which should now be removed. 
 Next, having procured a smooth stick of wood, or a thin iron rod 
 which will fit loosely through the hole in tlie top of the cylinder, it is 
 inserted into the cylinder so that it rests upon the piston. Tlie stick 
 should be kept vertical. The engine is turned until the stick appears 
 to be in the highest position, and a mark made on the stick with a 
 pencil at the edge of the hole. Another pencil mark is made about 
 ^ or 1 inch from the first nuirk. Now the engine is turned until the 
 second mark ccn-responds with the edge of the hole, and a mark is 
 made on the flywheel corresi)onding with the pointer which has been 
 fastened to the frame. The engine is turned over, ])ast the bottom 
 center, until the same mark again registers with the edge of the hole; 
 at this point a mark is made on the flywheel corresponding to the 
 position of the pointer. With a pair of dividers, or a flexible rule, 
 the distance between these marks is bisected and marked. This latter 
 mark is turned to the pointer, and cylinder No. 1 is on its exact top 
 center. 
 
 The other centers may be found from the first obtained mark on 
 the flvAvheel thus: In a four-cylinder engine No. 4 would have the 
 same mark as No. 1. For No. 2 and No. 3 another mark will have 
 to be placed directly opposite the one of No. 1 and No. 4. In a six- 
 cylinder engine, one of the remaining cylinders would have a mark 
 corresponding with the first, while a mark for each pair of the other 
 cylinders woidd have to be placed at 120° from the first mark, 
 connnonly spoken of as " placino; them on thirds.'"' 
 
 The nuigneto itself has to be " in step " with the engine. In the 
 timing of a high or of a low tension magneto there are certain points 
 in the revolution of a magneto when the intensity of the spark is 
 greatest ; this should be taken advantage of, whether it be a high or 
 low tension magneto. 
 
 If the engine has been equipped Avith a magneto, the drive gears 
 are marked on their rims so that with the marks on the different 
 gears corresponding with each other, the magneto is in step with the 
 engine. In such a case, if the gears have been shifted, it is a simple 
 matter to re])lace them. If, however, no marks be present, the wires 
 are connected to the terminals, and one of the valve chambers opened 
 so that the spark can be seen. The engine is now rapidly turned over 
 by hand, and the spark noted. Marks are made on the gears with a 
 
ELE.MENTAllV AUT().\L()TIVE ENtilNKKRlNG LKCTURES. 115 
 
 pencil, so this position can be found a<r:iin if nccessaiy. The icUer 
 <jear is now sliifted a coupk» of teeth, and this position indicated with 
 a dilf'erent mark: the eniriiie is lurned aaaiii and the spark noteiK 
 This process is repeate(K shit"tin<:- tlie <rears a coupU' of teetli each 
 rune. The mark cori'espondinjii with the hest spark slionid he seh'cled 
 and a permanent mark put on tlie iiears. 
 
 It is imjxjrtant. when attaehino- a iiia<rnet() to an en<j:ine. that the 
 <h-i\(' and (hi\en <>ears he keyed to their sliafts. after tlie rijiht posi- 
 tion has heen found. When tlie ma<^neto has been timed to "jive the 
 best sjiark at the top center, ami the s])ark h'ver advanced, the spark 
 would not b" as intense if the spi'ed of the cnjrine remained constant, 
 but as tlie spark is advanced for hi<2.ii sjx'cds oidy. the increased speed 
 of tbe maaiu'to will more than make up the deliciency and |)ro(bict' an 
 even better spark. As there are two dead points (birinir each revolu- 
 tion of the ina*rneto, it should be <'eared so that none of the dead 
 |)oints correspond with the sparkin«i- jjeriods. 
 
 When ecjuipped with a multij)le-unit coil and timer, the same rules 
 as api)lied to a batteiy iM|uipnient will be applicabU". and tlu' magneto 
 may be timed the same way. by turnijijr and testinii' the spark. The 
 .-|>ark pluii's may 1)(> taken out and laid on the cylinder, with the 
 calile> connected, thus makin<r the si)ark visible. AMien a distributor 
 is used, it must be timed so that the rotor contact registers with one 
 of the terminals for the spark cables for each cylinder before the 
 spark is to take i)lace. The contacts nmst follow the regular tirin<i; 
 order of the cylinders. If the magneto be e(iuii)ped with a self- 
 coutaiiu'd coil the same rule holds true, the only ditference is in the 
 wirinjj,'. 
 
 When a high-tension magneto is timed, the cables must be con- 
 nected to the s|)ark plugs in the regular firing order of the cylinders 
 to determine the order of sparking the plugs. They may be laid on 
 (he cylinder heads while the magneto is being turned over. The 
 gears must be shifted one tooth at a time until the spark takes place 
 at the right lime, which is about the top center when retarded. 
 
 The speed of a magneto is iletermined by the number of cylinders, 
 as well as the cycle of the engine. Since there must be four explo- 
 sions for each two rexolutions of a four-cylinder engine and as each 
 revolution of the armature produces two sparks, there must be one 
 rexdlution of the armature for I'ach revolution of the engine. 
 
 I'x'fore starting to lime an engine, it is imi)ortant to examine the 
 \alve gearing to ascertain whether the valves oi)en and close at the 
 proi)er time. If the valves be out of "time." first exanunc the valve 
 stems and ]>ush rods for lost motion, which should be no more than 
 the thickness of hea\y paper. When the valves open and clo.se late 
 as compared to ihe mo\('ment of the piston, the valve is said to hv late. 
 If all of the vahes be o|)erated by the same i-am shaft, the valves are 
 i»ouud to be "in step" with (>ach oilier, [providing there is no excessive 
 lost uiotion. but if one of the valves be early, or late, il is evidenl that 
 they are all out of time. If the exhaust and iidet valves be operated 
 by sejiarale cam shafts, it may hajipen that both sets of valves may be 
 out of lime with each other, at the same time being out of time with 
 the piston, or one set may be in time with the pistons, while the otliei* 
 set is out of time. The valves may all be considerably out of time, 
 and the engine will still run. but al the exjx'Use of reibiced power, 
 
116 TENTATIVE MANUAL OF INSTRUCTION. 
 
 increased fuel consuinption. and excessive vibration. Improper tim- 
 ing is detected by nnstead}' action, especially at the higher speeds. 
 
 On some engines the cams are made independent of the cam shaft, 
 and are keyed to the latter, hence, it is possible that, in overhauling^ 
 the engine, some of the cams may have been replaced wrongly. 
 Although the cams can not be shifted out of time with each other, it 
 is possible that the surface of some may -be worn more than others, 
 or on such engines where the cams act upon rollers carried by the 
 end of the push rod, or by a carrier, the roller and the pin may be 
 worn to such an extent as to make proper timing impossible without, 
 removal of the Avorn parts. This lost motion can not be taken care of 
 when adjusting the lost motion between valve stems and push rods; 
 only the lost motion in the direction of the valve travel can be 
 adjusted. The lost motion in the rollers, the carrier suspension, or 
 the push-rod bushings acts in a direction at right angles to the valve 
 travel and affects the timing. The main objection to lost motion in 
 the gear teeth would be the noise. When the cams raise the valves 
 against the spring action, the tension upon the teeth is upon their 
 driving faces, while when the valves seat again by the spring action, 
 the tension upon the teeth is on the reverse side, causing the gear 
 teeth to clatter back and forth several times during each revolution. 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LECTURE IV. 
 
 IGNITION. 
 
 { Iiistiiicth.ii ( 'liaits N(.s. 1, 5, 30, 31, 32, 33, 34, 35, 3G, 37, 38. Kqiiiimieiit : Dodge, 
 Cadillac, Class " V.." Wliiic.) 
 
 It is of prime iniportance that the aiitoinobili.st acquire a thorough 
 knowledge of ignition. Many of the troubles still encountered, not- 
 withstanding numerous improvements, have arisen from failure of 
 the ignition system to i)erform its proper function. The engine 
 may operate with an imperfect fuel mixture if th" ignition system 
 be in Avorking order, but any defect in the latter will, in nearly every 
 case, cause the engine to misfire, or stop. 
 
 The name electricity is applied to an invisible agent, known only 
 by its effects, and the various ways in which it manifests itself. 
 Copper, as it offers little resistance to the liow of the electric cur- 
 rent, is generally used for conductor.s. The current must have pres- 
 sure to overcome the resistance of the conductor. 
 
 The pressure under which the current flows is mv'a>ured in volts, 
 ami the ([uantity that passes, in amperes. The resistance with which 
 the current meets in flowing along the conductor is measured in 
 ohms. The flow depends upon the pressure and the resistance. The 
 flow of the current is proportioiuil to the voltage and inversely pro- 
 portional to the resistance. The latter dei)en(ls uj)on the material, 
 length, and diameter of the conductor. The current always flows 
 along the path of least resistance and there should be little or no 
 leakage. This is accomplished by insulating the wires, that is, cov- 
 i'ring them by wrapping tliem with cotton or silk thread, or other 
 insulating nuiterials. 
 
 A defect in the insidatiou which allows the cuirent to leak an<l 
 return to the source without doing its work, is a short circuit. The 
 conductor which receives the current from the source is called the 
 lead, and the one by which it flows back, the return. When wires 
 are used for both lead and return, it is called a metallic circuit; 
 when the metal of the engine is used for the return, it is called a 
 ground circuit. Tlii> term originated in telegraphy, where the earth 
 is used for the return. In ignition diagranw then, the exi)ression 
 "to ground" means to connect the point with the metal of the en- 
 gine. 
 
 \\'hene\ci- the ciiiivnt is checked by a re>istance. the eni'igv of its 
 liow is comerted into heat, which makes electricity available for 
 ignition. This is acc(Mni)lished in two ways, (1) iiv suddenly break- 
 ing a circuit. an<l {'2) by j)lacing in the circuit a i)einiaiu'nt air ga|) 
 which the current must jump. In either case, the intense heat caused 
 
 117 
 
118 TENTATIVE MANUAL OF INSTRUCTION. 
 
 by the enornioiis resistance interposed, instantly produces a spark, 
 which ignites the charge. In these two methods of pro(hicino- the 
 si)ark, the tirst is known as the make and break, or low tension, and 
 the second, the jump spark, or high tension. 
 
 An electric current is said to be (1) direct, when its direction is 
 continuous, (2) alternating, when it flows rapidly to and fro in op- 
 posite directions. (3) primary, Avhen it comes directly from the 
 source, (4) secondary, when the voltage and amperage of a primary 
 current have been changed by a transformer or induction coil, and 
 (5) low tension, or high tension, according as the voltage is low or 
 high. 
 
 High and low tensicm currents vary; i. e. — a high tension current 
 is capable of forcing its way against considerable resistance, where- 
 as, a low tension current must have its path made easy. A con- 
 tinuous metal path is an easy one, but an interruption in the metal, 
 as the permanent air gap of a spark plug is difficult to jump. Air 
 is such a poor conductor that it is usually spoken of as a noncon- 
 ductor. The latter term should not be encouraged, as, strictly speak- 
 ing, there are no nonconductors; the word insulator is to be pre- 
 ferred. 
 
 The low tension current is only able to produce a spark \\hen 
 parts are provided in the path, and so arranged tliat they may be 
 in contact and then suddenly separated. The low tension current 
 will, as the separation occurs, tear off very small metallic particles 
 and use these as a bridge to keep the path complete. Such a bridge 
 ^ called an arc, the heat of which is used for ignition. 
 
 The poles of a magnet are the two regions in which the magnetic 
 property is strongest. In a bar-shaped magnet the poles are at the 
 ends; half-way between the poles there is no attraction at all. In 
 a bar magnet, that end which tends to point toward the north is 
 called the north or i)ositiA'e pole, and the other the south or negative 
 pole. When a cui-rent of electricity passes through a wire, what is 
 known as a magnetic field is produced. A magnet may be produced 
 by passing an electric current through an insulated wire conductor 
 coiled around a core of soft iron. This is called an electric magnet. 
 If the bar be of soft iron, it will be very strongly magnetized, but 
 will not retain its magnetism for any length of time after the current 
 ceases to flow ; if of steel it Avill not be magnetized so strongly nor so 
 (juickly, but will retain its magnetism for a great length of time 
 after the current is shut off. In winding wire aroimd a bar, it 
 should be wound continuously in one direction, as the polarity, or 
 location of the poles of the bar, depends upon the Avay the current 
 flows through the wii'e. The poles may be identified by holding a 
 permanent magnet or a compass needle near one pole of the electro- 
 magnet; the north pole of one Avill attract the south pole of the 
 other, and vice versa. 
 
 If the coil of an electromagnet be surrounded by a second coil of 
 insulated wire an induced current is produced in this second coil 
 by what is known as induction, each time the current in the inside 
 coil begins or ceases flowing. The inside coil is called the primary 
 winding, and the outside coil the secondary winding. Similarly, the 
 current passing through the inside coil is called the primary current, 
 and that in the outside coil, the secondary or induced current. 
 
ELEMENTARY AUTO.MOTIVK KXiilNKKmNCi LECTURES. 119 
 
 U\ \"!U\vin^ the relative miiuher of turns in the two coils the ten- 
 sion oi- Voltaire of the two currents is ehantrcHl proiwrtionately. That 
 is, if the primary windina he composed of ten tnrns and the second- 
 ary of one hundred, the voltaiie of the secondary cuirent is increased 
 approximately ten times that of the |)rimary. Tliis princij)le is 
 employed to produce the extremely hi<rh tension cmrent necessary 
 with the jump-si)arlv method of ignition. 
 
 An electric current may he produced by (1) chemical, and {'2) 
 mechanical means. In |)ro(liuin<j: electricity hy chemical action, two 
 dissimilar metals, such as copper and /.inc, called electrodes, are 
 innnersed in an excitin*; Hiiid. When the electrodes are connected at 
 thi'ir terminals hy a wire or conductor, a chemical action takes place, 
 prodncin<r a current which Hows fioui the copper to the /inc. That 
 terminal from which thi' cuiient flows is called a plus or positive 
 pole, and the other eh'ctrode terminal a minus or ne<:ative pole. 
 
 This device is called a crll. and the coml)ination of two or more 
 connected so as to form a unit, is known as a hattery. The word 
 '• battery " is frequently used incorrec-tly for a sinjile cell. It requires 
 more than one cell to form a hattery. Cells are classified primary 
 or secondary, accordin^j as they generate a current of themselves or 
 re(|uire to he char<red from an external source before yieldinji a 
 cun-ent. In the latter type ener<ry is stored by chemical action which 
 is afterwards yielded as current llowiuo- in the opi)osite direction to 
 that of the ciiar<rin<»- current. An (dectric cui-rent can also be pro- 
 duced by mechanical means. 
 
 A dynamo has an electr()ma<inet. kncjwn as a Held magnet, which 
 produces a maunetic field, and a coil of wii-e oi' Mi'maturc whicli. 
 when revolved in the maiznetic Hidd. develo|)s electric current. A 
 ma<^neto has t I ) a peiinaneiit maiinet to jiroduce the ma<2:netic 
 field, and (2) an armatuie whicli is usually arian<i:ed to revolve 
 l)etween the poles of the mairnet. 'i1ie basic principles upon which 
 dynamos and magnetos operate are the same. Mairiu'tos are divided 
 into two classes: (1) low tension, and ('2) hi<rh tension. accordin<; as 
 they generate a current of low or hi<ji;h \()ltai:e. Low tension mag- 
 netos are used for make and hreak ignition, and the high tension 
 type for the jump-s|)ark svstem. A low tension magneto in combina- 
 tion with a secondarv induction coil may be used to pi'oduce a high- 
 tension spark. 
 
 To obtain a spark in high-tension ignition, a si)ark plug is u.sed 
 which consists of two stationary electrodes, one of which is grounded 
 to the engine cylinder and the other insidated. The points of the elec- 
 trodes are permanently separated from each other by about ;-,'2 <>f !iii 
 inch, the space between the points being known as an air gap. This 
 space oft'ers so nuich resistance to the How of the electric current that 
 a very high pressure is re<|uired to cause the current to burst through 
 the air gap and ]>roduce a spark, hence the term "high-tension ig- 
 nition." Since the >park jumps from one electrodi' to the other, this 
 method of igniting the charge is also known as the jump-spark sys- 
 tem. The spark itself is properly desciil)ed by the prefix, high ten- 
 sion or secondarv. 
 
 In the prinluction of the high-tension si)ark'. two distinct circuits 
 are necessary: a low tension or primary ciicuit. and a high ten-ion or 
 sec(^n(larv circuit. The current which Mows throuiih the low-tension 
 
120 TENTATIVE MANUAL OF INSTRUCTION. 
 
 circuit is called the primary current, and that which it induces in the 
 high-tension circuit, the secondary current. 
 
 The high voltage necessary to produce a secondary spark is ob- 
 tained by a device known as a secondary induction coil, which 
 transforms the primary current of low voltage and high amperage 
 into a secondary current of high voltage and low amperage, that is, 
 the volume of the current is decreased and its pressure increased. 
 
 The general principles upon which high-tension or jump-spark 
 Ignition is based is as follows : An automatic device is placed in the 
 primary circuit, which closes and opens it at the time a spark is re- 
 quired. When the circuit is closed, the primary current flows 
 through the primary winding of the coil and causes a secondary cur- 
 rent to be induced in the secondary winding. A spark plug being in- 
 cluded in the secondary circuit opposes the flow of the current by the 
 high resistance of its air gap. Since the pressure of the secondary 
 current is sufficient to overcome this resistance, it flows or " jumps " 
 across the gap, and in so doing intense heat is produced, resulting 
 in a spark. 
 
 Sometimes the spark is obtained by keeping the primary circuit 
 closed except during the brief interval necessary for the passage of 
 the spark at the plug points. A secondary spark then may be pro- 
 duced by either open or closed circuit working, that is, the primary 
 circuit may be kept either open or closed during the intervals be- 
 tween sparks. 
 
 A contact maker is that which momentarily closes and breaks the 
 circuit at the time of the spark. A contact breaker is that which 
 keeps the circuit closed except at the time of the spark, A contact 
 breaker is used to advantage on small engines run at very high speed, 
 as it allows time for the magnetism or magnetic flux in the core of 
 the coil to attain a density sufficient to produce a good spark. 
 
 A timer is a device which controls the primary current only. A 
 distributor is a timing device which controls both the primary and 
 secondary currents, and an interrupter is a contact breaker on a mag- 
 neto which l)reaks the primary circuit at the time a spark is required. 
 
 The current from a nonsynchronous alternating current magneto 
 produces very little wear on the vibrator points because the current, 
 in the aggregate, is in each direction for one-half the time. The 
 wear on vibrator points may be reduced when a battery is used by 
 pei'iodically changing the direction of the flow of the current. This 
 is done by reversing the wires attached to the battery terminals. 
 
 Some advantages of ignition with high-tension magnetos are that 
 the wiring is greatly simplified since the coil and condenser are a 
 part of the magneto. Also, hand advance of the spark is not re- 
 quired. The hand advance is not necessary, owing to the intensity 
 of a magneto current increasing with the speed. Hence, when run- 
 ning slowly, the spark produced in the cylinder will be weak and 
 the charge will be ignited slowly. At high speeds, the strength of 
 the current being greater causes the charge to ignite more rapidly; 
 this charge produces an effect equivalent to advancing the spark. 
 
 When starting an engine on a magneto the crank must l)e turned 
 faster than when a battery is used, l)ecause the armature must be 
 turned at a certain speed to generate the required current. Ordinary 
 spark plugs are not well adapted to a magneto, because the current 
 
p:lementary automotive engixeering lectures. 121 
 
 l>ein^ stroiiofor than that fiiiiiislicd l)y a l)att(M-v, the oivatcr lioat of 
 the cm rent tends to burn the sU'nder jxMnts. Therefore. Avith a mao^- 
 iieto thev niiisl he hu'jrfr for satisfactory \vorkiii<r. IMie ^ap of a 
 ma<rneto |>hi<r shoidd he less than that of an ordinary l)hi<r. l)ecause 
 the. cuii-ent. whik' of <j:reatei- ani|)era.ii;e and heating vahie. is of less 
 V(>lta<;e than with a battery system. The <j:ai) shonld not he more than 
 one sixty-fonrth of an inch. It is important that the revolving 
 switch, which distributes the secon<laiy ciincnt. and the contact 
 breaker should lie kept clean. 
 
 Dual i<;nition is one with 1 wo modes of ignition ha\in<j: one or 
 more parts in connnon. and (hmble i<2:nition is two inde|)endent moans 
 of i<rnition ha\in<x no parts in connnon : thus, if anythinjf should 
 iiappen to one system the other may lie l»i()U<rht into use. 
 
 To successfully cope with ipiition troubles theic aic two re(iuisites: 
 (1) A thorouoh knowledge of the system used, and ('2) a well 
 ordered course of procedure in lookintr for the cause of the trouble. 
 In many i^rnition systems the chief ditliculty encountered in the loca- 
 tion of defects arises from the fact that faults in different ])arts of 
 the cii'cuit sometimes make them.selves manifest by the same symp- 
 tom.s. If each defect liad it> individual symptom, locating:- the troulile 
 would b(» comparatively easy; but. as it is. it is sometimes (juite diffi- 
 cult to find till' defective j)arts. In ijeneral. the followino- method 
 should be adojited to IcK'ate ifrnition troubles: 
 
 ( 1) The source of current sui)i)ly should be examined ; if a battery, 
 each cell should lie tested separately, and any one found to be weak 
 removed. If a ma<rneto i)e used, it should be disconnected and the 
 aimature turned by hand: in case the field maj^iiets liave not lost their 
 propel- stren<rth the arnuiture should turn percept ilily hard diii-ino- 
 <'ei-tain |)ortions of each revolution. 
 
 {'2) The ])rimarv cii-cuit should l)e examined foi- breaks: all con- 
 nections made brifrht and secured Hi'udy by the i)indin<r screws, and 
 the timer contacts cleaned. 
 
 {■\) The s|)ai-k-plu<r ]M)ints shouUl be cleaned and tlu> air nap made 
 the proper len<rth — al)out one thirty-second of an inch. 
 
 (4) The vibrator contacts should lie made flat and cK-aii. and the 
 vibrator properly adjusted. 
 
 In testinir the spark phiir it should lie unscrewed and placed on the 
 <ylinder without disconneciiuir the wire to tlie insulated electi'ode: 
 tli(> body of the ])lu<r oidy should touch the metal of the cylinder. On 
 <'rankinp; the enofino the spark should be •" fat " if everythin^jf be in 
 jL'o<i(l condition; if a weak spark be produced it may be due to either 
 a loose termimd. run-down battery, or badly ad justed \ibratoi-. A^'hen 
 no spark can be obtained the entii'e system must be examined aiul 
 tested. be<jinnini>f i»t the battery. 
 
 /'/>/</ f<:sh'/i(/ in inulfi-cylitiilcr ( ik/'uh'x. — Aftei- staitiuir the eiiirine 
 all pluiT wires are fri-ounded except one. thus runnin«r the en<j:ine on 
 <tne cyiindei-. In case there he no misfii-in<r after testin<r :>< vaiious 
 enjrine speeds, it can be taken for irranted that the phii: is sound. 
 The remainin<r plu<rs are tested in the .same manner, ^^'hen a multi- 
 unit coil is used, a faidty plu": uuiy be located by holdin.ir down all 
 the vibiator blades but one. so that only one spark pluir operates, 
 liunniufr each cylinder separately by this means it can easily be 
 
122 ET.EMKXTARV AUT()]\lOT[VE EXGINEERING LECTURES. 
 
 ascertniiR'c^. \ylii(.-h |)luo- is defective. Some eoils ai'e provided with 
 little knobs for cuttinij out cylinders in the manner just described. 
 
 Complete hrcdl- in the irh-hu/. — The cnsine is placed u])ou the 
 sparking point, the ])riniary switch closed, and th.e two terminals of 
 the suspected wire touched with a test wire. A flow of current indi- 
 cates a break. 
 
 Pavfkd l)f('(t]x In Hie ir'/ihuj. — A partiifl break or one held together 
 by the insulation may sometimes be located by bending the wire 
 sharply at successive points along its lenglh, the engine being at the 
 sparking point and the switch closed as before. 
 
 Primary nhort eircuifs. — The primary wires should be disconne ted 
 from the coil, leaving the ends out of contact with anything. There 
 is a short circuit if, on touching the switch points momentarily, a 
 spark appear. A short circuit may sometimes be overcome by cleai'- 
 ing all wires of contact with metallic bodies, and i)ulling ea h wire 
 away from the others which were formerly in contact with it. 
 
 Secondary short circultx. — The secondary lead fi'om the spark phig 
 should be disconnected. Under this condition the high tension cur- 
 rent may sometimes be heard or seen discharging from the se ondtiry 
 wire to some metallic portion of the car. Water in contact witli th ' 
 secondary Avire will sometimes cause a short circuit unless the insu- 
 lation be of the best quality. 
 
 Th^e. primary sir itch. — This portion of the i^rinuiry circuit some 
 times causes trouble by making poor contact. This is generally due 
 to the deterioration of the spring.portion of the metal, which gi-adu- 
 ally loses its resiliency. Snap switches sometimes fail through the 
 weakening of the springs which hold them in the "on" or "'oft'"* 
 position. The contacts of a switch should be kept in good condition. 
 
 Primary connectiotis. — All liinding posts and their connections 
 should be clean and bright. The wires should be firndy secui'ed to 
 the binding posts, as a loose connection in the primary circuit is 
 often the cause of irregular misfiring or the stoi)i)ing of the engine. 
 
 Vibration. — Since the wires are subject to constant vibration, a 
 number of strands of fine wire is better than a single heavy wire, as 
 the latter is liable to be broken. In securing the wire to the binding- 
 post, care should be taken that all the strands are liound. 
 
 Tinwrs. — These may give trouble by (1) ])resence of dirt. (2) 
 loose contacts, or (3) division of the spark; this latter effect is some- 
 times caused by metallic particles wearing off the revolving part 
 forming a path so that the spark })asses from the revolving i)art to 
 more than one contact. 
 
 Coils. — The part of a coil which re<iuires most frecjuent attention 
 is the vibrator. The contact points are subject to deterioration on 
 account of the small spark always present between the points when 
 the coil is in operation. In time, the points become corroded and 
 burned, and therefore require to be resurfaced by smoothing with a 
 fine file. A faulty connection to the condenser is at once shown by 
 large sparks at the vibrator points. Any repairs to a coil, aside from 
 the vibrator, should always be done by an expert, as the construction 
 is very delicate. 
 
 Sj)ark plugs. — Kepeated failure to start when the coil vibrator 
 operates, indicates a faulty spark plug. A rich gasoline mixtur.^ 
 often leaves a carbon deposit, which, being a partial conductor, short 
 
KLK.MKXTAltV Al'TOMOTIVK KXtilXKKltlXG l.ECTriiKS. 123 
 
 circuits the pluo;. The porcelain insulation, on account of its hrittlc- 
 n&ss, may crack inside the sleeve, allowing a spark to pass theiv in- 
 stead of at the orap. Mica insulations sonietiuies hcconie saturated 
 with oil, causing the layeis to separate. ixTuiitt iuir :i short ciiruit. 
 
 Eixjhw ni'/sfres anij piiiilly .stops. — This may be due to the ex- 
 haustion of the battery, and is indicated l»y a weak spark and vei-y 
 faint vibrator action. 
 
 /ifif/hic ,sU(hfe/J'i/ sfojhs. — This is generally causi-d i)y a bioken wire 
 or loose switch which does not stay closed. In the case of a single 
 cylinder, the broken wire may be either in the piiuiary or secondary 
 circuit: if a multi-cylinder engine, llic i)i-e.ik i^ in the primary 
 circuit. 
 
 Kfi(/lii< (/o(-s not stdi't. — Usually cau>ed by ( 1 ) primary switch not 
 closed, (2) battery weak or exhausted, (^5) entire or partial bieaU in 
 Avire, (-i) loose terminal. (5) moisture on si)ark plug. (('>) fouled plug. 
 (7) spark too far retarded or advamcd. or (S) too slow rrankiuL^ 
 with magneto ignition. 
 
 Engine nins -fitfullij. — Frecpiently results iVom a partial break in 
 the wiring, especially in the primary circuit. 
 
 J*r< i</nitioii. — Caused by (1) some snnill particle in the cylinder 
 becoming heated to incandescence. (-2) the electiodes of the sj)ark 
 l)lug becoming red hot. oi- ('.\) intermittent short circuit in the pri- 
 mary. 
 
 EiKi'nii i-uiis irifh siritch- opfn. — T^sually caused by (1) o\erheated 
 engine or plug i)oints, (2) i)rimary short circuit. (8) defective switch, 
 or (4) an incandescent particle inside the cylinder. 
 
 EiKjinc nii.s-frnx. — This may be caused by (1) weak battery. (-1) 
 partial break in conductor. {'■\) loose or disconnected terminal. (4) 
 intermittent shoit circuit in the secondary. (.'>) faulty action of either 
 timer or \ibi-ator contacts. (('.) bent Nibi'ator blade. (T) fault\- s|)aik 
 plug, or (S) air gaj) too large. 
 
 K uock'iiKi of i/it/!iii .— TiH) ad\ance(| a spark sometimes produces 
 t Ids effect.' 
 
 I\nocl'h)(/ hi the ci/Jinder. — The form of iiinisual iioi>e commonlv 
 descrilied as ''knocking" consists of a legnlar and contimious tap- 
 ping in the i-ylinder. winch is so unlike any sound usual and normal 
 to oj)eration. that, once heard, it can not be mistaken. Too nnich ad- 
 vance of the spark sometimes j)roduces this result. 
 
 Loss of poire)- ii'ithoiii misfires.— 'V\\\s may be due to badly ad- 
 justed coil contacts, poor spark, or incorrect timing. 
 
 E.rp?osie/ns hi fh/' muffler. — Tliese are usually caused by mi-liiing. 
 j)artiHlly charged storage battery, or by one cyjindei" not working. 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LKCTrRE V. 
 
 FUEL SYSTEMS. 
 
 ( Instnirti.m ("liarts Nos. 1, 5, 13, 14. ir», 10, 17, 18, 19, 28. Equipment: DoiIkc 
 Whito, CjuHllac U. S. A. Staiulanl, RayfieUl, Stroniberf?, Ball & Ball, Zenitli. 
 Marvel, ami Stewart carhiiretor.'^. ) 
 
 AVliili' it is api)aivnt that the chief fuiiction of ii cuiburcting device 
 is to mix hydrocarbon vapors with air to secure mixtures that will 
 burn, tliere arc a number of factors which must be considered be- 
 fore descril)in^ the principles of vaporizinjo; devices. Almost any 
 (levire which permits a current of air to pass over or throujifh volatile 
 liquid will produce a gas which will explode when compressed and 
 ignited in the motor cylinder. Modern carl)uretors are not only 
 called upon to supply certain ([uantities of gas, but these must de- 
 liver a mixture to the cylinders that is accurately proportioned and 
 which will be of proper composition at all engine speeds. 
 
 Flexible control of the engine is sought by varying the engine 
 >peed by regulating the supply of gas to the cylinders. The power 
 plant should inn from its lowest to its highest speed without any 
 iir(>gularity in torque, i. e., the acceleration should l)e gradual rather 
 than spasmodic. As the degree of conq:)ression will vary in value 
 with the amount of throttle opening, the conditions necessary to ob- 
 tain maximum power differ with varying engine speeds. "When 
 the throttle is barely opened the engine speed is low, and the mix- 
 ture must be richer in fuel tlian when the throttle is wide o]ien and 
 the engine speed is high. 
 
 When an engine is turning over slowly the com})ression has low 
 value and the conditions are not so favoral)le to rai)id combustion 
 as when the conqiression is high. At high engine speed the gas 
 velocity through the intake piping is higher than at low .speed, 
 and regular engine action is not so apt to be disturbed by condensa- 
 tion of ]i(|uid fuel in the manifold due to excessively rich mixture 
 or superabundance of liquid in the stream of carbureted air. 
 
 The duties of a carburetor are to so control the supply of air 
 and gasoline tliat the resulting mixture will always contain the 
 two ingredients in tlie proper proportions. There must not be too 
 mucli gasoline vapor, as fuel would be wasted either by being de- 
 conq)ose(l into soot, or mibuiiied. on account of insuflicient su|)ply 
 of ail' to consmne it. Again, too much air, thougli the mixturi' 
 should ignite, woidd lower the temi)erature of combustion and thus 
 diminish the expansion. 
 
 125 
 
126 TENTATIVE MANUAL OF INSTRUCTION. 
 
 The two most important types of the carburetors are the "'■ sprayer " 
 and the " surface " carburetors. In the operation of the spraj^er car- 
 buretor, the fuel is atomized through a minute nozzle and mixed 
 with a passing air current. The action of a surface carburetor con- 
 sists in passing air over the surface of a small '" puddle '' of the fuel. 
 The sprayer is the pi'evailing type. For this purpose the essential 
 features necessary to produce a proper ftlel mixture are shoAvn in the 
 instruction chart. (See Instruction Chart No. 13.) The drawing- 
 illustrates a receiving chamber and mixing chamber, the two being 
 connected by a small passageway or duct which terminates at the 
 sprayer, made adjustable by the needle valve. The lower end of the 
 mixing cliamber is open to the atmosphere, while the upper end is 
 provided with auxiliary air ports having a collar, or sleeve, with 
 Avhich to adjust the o[)ening of the ports to the atmosphere. 
 
 In explaining the action of this rudimentary carburetor it is as- 
 sumed that the receiving chamber is filled with gasoline to a level, 
 very lu^ar the elevation of the spray nozzle, and that the supply is 
 replenished as it is used so that the liuid level is kept consistent. The 
 upper end of the mixing chamber of the carburetor is connected to 
 the engine beyond the throttle, as shown in chart. On each suction 
 stroke the piston motion causes a partial vacuum in the mixing 
 chamber; tlie intensity of the vacuum depending ui)on the speed. 
 
 Assuming the engine to be woi-king at slow speed with a heavy load, 
 and the auxiliary ports closed by the sleeve, the gasoline supply may 
 be adjusted by the needle valve so that the engine will receive the 
 proper proportion of gasoline vapor and air froih the carburetor. 
 The air supply entering at the bottom of the carburetor is the pri- 
 mary air. The air supply entering thi-ough the auxiliary ports is the 
 secondary air. If part of the load on the engine be removed so that 
 it will run. say. twi e a.s fast, the amount of air and gasoline deliv- 
 ered for each charge will not be the same, for under these conditions 
 the mixture will becouie too rich; that is, too much gasoline will be 
 fed for the amount of air ])assing through the inlet at the lower end 
 of the mixing chaml)er. This is caused by an excess of gasoline, and 
 is due to the fact that, in order to get twice the amount of air 
 through the inlet, the suction has to be more than doubled to compen- 
 sate for the increased frictional resistance set up by the higher ve- 
 locity of the air passing through the inlet. The suction, or degree of 
 va'^uum in the carburetor being uiore than doubled, will induce a 
 flow of more than twi( e the amount of gasoline. The velocity of the 
 ail' increasing in passing through the inlet is due to the expansion 
 of the air in entering the carburetor, resulting in an increase of 
 velocity more than twofold after expansion. This suction may be 
 restored to its normal condition so that the mixture will not become 
 too rich by slightly raising the sleeve so as to partially open the air 
 })orts. This alloAvs some air to enter tlirough the auxiliary air ports, 
 thus reducing the velocity of the entering air and relieving somewhat 
 the suction at the lower inlet. The amount of opening of the auxil- 
 iary air ports necessary for any ehauge of engine speed is found by 
 experiment. 
 
 The engine speed nuiy be maintained constant under varying load 
 if a throttle valve be placed in the passage between the auxiliary 
 ports of the carburetor, the load may be altered without any varia- 
 tion in the engine speed, by adjusting the throttle opening. 
 
ELEMEXTAKV AUTO.MuTIVK KNlil X KKltlNG LiX'TlllKS. 127 
 
 The modern carbuii'tor dift'eis fi'oiu tlie riulimentarv or piiniative 
 de\ ice shown in chail. In actnal eonsti net ion antoniatie devices are 
 eiiii)h)yi'd to maintain the <rasoline in the receix inii" chamher at con- 
 stant le\el and t<» ailjnst the anxiliarv port openin<rs to tlilierent en- 
 irine speeds. 
 
 J'he. term float chaml»er is used instead of receiving chamlier. sime 
 a lh»at is ahnost always used to rejinlate the How of irasoline into the 
 chamber, and is an automatic device to maintain the <£asoline supply 
 in the float chamher at the same elevation as that of the spiay no/./le. 
 Ihis is necessai y because an initial siution is i-etjuired to lift the 
 ^"•asoline to the mouth of the no/zle before sin'ayinjr can bi'ixin. The 
 sli<ihtest suction only is ri'(|uii'ed to draw air throu<>h the ])riuiary 
 air iidet: tlu-re is. lioweNcr. a ci'rtain mininnnii suction ludow wliich 
 no <rasoline can be fed, dependin<r on the dif1\'rence in the level of the 
 >u|)ply and tiu' level of the spray nozzK*. This levt'l is uiaintaiiu>d 
 by ;i "• thcil feed" (h'xice which consists of a ( ork or hoMow uictal 
 lloat placed in the Moat chaml)er. It is connected so as to operate the 
 ifasoline inlet \alve. usually by means of li'vcrs. These are arraniri'd 
 in such a manner that as tlu' iiasoline entei'^ the float chambei- throu<rh 
 the iidet \al\i' the Hoal rises, and in so doin^- closes the vahc. thus 
 shuttin<i" off the sni)ply when the «ias()line reaches the desired level. 
 
 A simple Hoat feed tonstriiction is -hown in tlu> chart. The lloat 
 is (onstructed (or.centric with the iidet \alve; that is. it i,< placed 
 aroimd the samei-enter. In the l)ottom of the float chaml)er is a small 
 tid)e through which the aas«>line must flow to the spray no/,zl(\ ( )nc 
 object of this tube is to prevent small particle^ of dirt and bubbles of 
 water that may be in tlie uasoline from directly entering" thi' spray 
 no/./le. The plu<> at the bottom of the Hoat chamber has a wire 
 screen to ( atch any foreiirn matter that may be in the <rasoline. in 
 order that it may not lodiZe in the spray no/zle and im|)ede the i\o\\ 
 of the li(|uid. 
 
 There should be means of adjusting- the height of the float to suit 
 tlifl'erenl grades of gasoline, as the level of the float de]iends upon the 
 specific gravity of the licpud. Counterweights are em])loyi'd and this 
 (onslruction is di«siiable owing to the facility with whit-h the fuel 
 level can be adjusted. To this end the counterweight is either in- 
 creased or diunnished. In oi-der to obtain uniform residts. esjx' -ially 
 where a car is operated on hilly roads, the Hoat chamber with its 
 float slioidd be constructetl (oncentrie with the si)ray nozzle, so that 
 any iiK lination of the car. in ascending or descnding a hill, will not 
 tlisturb till' gasoline level with rid'erenc e to the noz/le. 
 
 Floats are usually made <if cork or sheet metal, ("ork floats are 
 liable to ixM-ome saturated with gasoline, thus losing their bouy- 
 ancy. Metal floats sometimes leak. A lloat -hoidd be witliout work- 
 ing joints, and i)articularly without frictional contacts with l(>vers. 
 -V float chambei- should be constructed to o|)en at the bottom. This 
 facilitate- removal of any watei-, ice or dirt, and removal of the float 
 its(df. without opening the top and permitting dirt to fall i'.i fj'om 
 above. 'I'he float and removable bottom can be replaced with a 
 sfi-eam nf gasoline flowing upon them, which will wash away i)ar- 
 ti«-|e> of dirt, if any accidentally get on the i)arfs while being le- 
 placed. A\'ith a top opening, ice in the bottom of the chambei- may 
 not only -upport the float and picvi-nt it acting to ailmit gasoline. 
 
128 TENTATIVE MANUAL OF INSTRUCTION. 
 
 but may also bind the float so tirnily that it can not be removed tO' 
 permit removal of ice, which may prove an unpleasant predicament 
 if away from means of warming the carburetor. 
 
 The fuel flow should enter from a single direction, either up or 
 down, so that no pockets exist in which Avater or dirt may gather. 
 The inlet needle valve may be kept tight and in perfect working 
 order by occasional grinding. To facili^ate this, the construction of 
 the carburetor should he such that the valve is easily accessible. A 
 feature which tends to keep the inlet valve in good condition is that 
 the motion of the car tends to move the valve to some degree, even 
 though slight, which movement serves to force away any particles 
 of dirt that may lodge on the point during the passage of the liquid. 
 On this account, it is best if the float and valve be fixed one to the 
 other, so that the point partakes of the motion of the float and liquid 
 in the chamber. The float chamber must be provided with an air 
 vent to prevent the accumulation of any excess pressure which would 
 interfere with the proper flow of the gasoline. 
 
 A float pin or " tickler " is a device for depressing the float to 
 obtain an excess of gasoline Avhen such is required for starting the 
 engine. A rich mixture may be obtained in starting, Avithout tick- 
 ling the carburetor, by throttling the primary air supply. Sonifr 
 motorists regard it as a necessary preliminary in starting to " tickle '' 
 the carburetor, but carburetors difter; AA'ith some it is necessary that 
 the level in the float feed chamber be high, in others not so high. 
 Some carburetors flood easily, Avhile others never flood. 
 
 It is as difficult to start on an over rich mixture as it is Avith a lean 
 one. Any small tickling of the carburetor serves to start the nozzle 
 and create a small amount of mixture. But this process soon floods 
 the carburettor, and as the quantity of air supplied is small and 
 can not be increased to any extent before the motor starts, flooding 
 is apt to fill the inlet manifold Avith almost pure gasoline A^apor and 
 the motor Avill not start. 
 
 • Many motors Avill start Avithout touching the carburetor, and in 
 the case of others the process of starting is rendered far easier hy 
 the moderate applicatioii of attention of this sort. In priming a 
 carburetor the float pin should be depressed and held doAvn for a 
 feAA' seconds. This Avill cause as much, if not more, gasoline to enter 
 in a given space of time than if the pin be worked like a pump. 
 The latter operation as frequently performed is liable to injure the 
 float. 
 
 The float pin is usually arranged to pass doAvn to the float through- 
 the air vent tube. Since gasoline has considerable AA'eight, and con- 
 sequent inertia, the passage to the nozzle should be both short and 
 large. If the passage be short, the liquid will respond more readily 
 to the suction; if large, the friction Avill be less on account of the 
 reduced velocity of flow. With a long passage, the effect of inertia 
 is more marked, causing the liquid to respond less quickly to the suc- 
 tion, the strength of which changes during each intake stroke. On 
 account also of this inertia effect, the liquid does not get started 
 until a considerable volume of air has passed the nozzle, making the 
 early part of the charge too lean. Noav, as the suction decreases, 
 the inertia of the liquid causes it to continue to floAv making the 
 latter portion of the charge too rich, and probably leaving betweeni 
 
ELKMEXTAHY AUTOMOTIVE ENGINEERING LECTURES. 129 
 
 (•liiirjj;('s imsprayod (ln)i)s of liiiuid. wiiicli cithei- fall on tlio walls of 
 the larluirctor oi" arc (liaA\ n into tlic eniiino. 
 
 Tho sjJiayini:- ctl'cct in tlic sin>i)li' form un///.\v is U'.s> inarkod tiian 
 that obtained with no/zlcs ha\in<i" a number of slots, llowcvei-, 
 with the single nozzle, there is less danger of it becoming clogged. 
 The operation of a nuUti-slot nozzle is nndoubledly better tlian one 
 with a single o[)ening, bnt it is necessary for the construction to l)e 
 such that it may be readily w ithdrawn to clean the small spray s]ot<. 
 
 'J'he amount of licjuid passing liu-ough the nozzle nuiy be varied by 
 an adjustable needle or metal rod haxing a conical point. The needle 
 valve, which regulates the sup})ly of fuel at the nozzle. >houM have 
 suitable connections so that it may l)e adjusted by the operatoi-. and 
 enable him, while operating the car, to vary the i)roporti<)n of the 
 mixture, and thus secure the givatest power by ti-ial, as well a> t(^ 
 accommodate the ilevice to the tenijierature and humidity of dilferent 
 days, and also to the gravity of ditl'erent grades of fuel. 
 
 Some carburetors are fitted with two or more simple nozzles, the 
 idea being that the sex'cral nozzles forming the unit, by coming intoi 
 action progressively as the ])ower demand increases, will product; 
 the same eti'ect as though several separate carburetois were used, each 
 in turn being brought into action. 
 
 The small inclosure or passageway containing liu' spray nozzh^ 
 is called the mixing chamber. The mixing chamber, as its name 
 implies, is the place where gasoline and air are brought together in 
 jjroper proportion and mixed to form the fuel chaige for the engine. 
 It is provided with a main air inlet and auxiliary ports as before 
 described, but the latter are arranged to ojierate automatically. The 
 outlet to the engine is fitted with a Ihi'ottle vahc peiinilting the 
 »|uantity of the mixture to l)e varied. 
 
 The construction of the mixing chamber with its ai)pendages fol- 
 lows substantially the arrangement shown in the chait. This illus- 
 trates a mixing chamber with the spray nozzle located in the center. 
 The adjustable needle valve regulates the (low of gasoline to tin* 
 nozzle. The mixing chamber is open to the atmosphere at its Iowit 
 end, through which the primai'v or main air sui)ply enters. A 
 secondary or auxiliary air sui)ply is admitted through the ()i)enings. 
 
 In operation, the pressuiv in the mixing chamber is lower than 
 that of the atmosphere; the degree of vacuum depends on the amount 
 of throttle opening, the engine speed, and the amount of opening for 
 the primary and secondarj' air sujjply. (iasoline, as it is sucked out 
 of the nozzle, made up as it is of hydrocarbons of diH'erent values 
 from the point of view of weight and volatility, will ludd t(» the 
 globular form with more or less tenacity, depending upon condi- 
 tions. 
 
 It should be noted that doubling the diameter of these globules in- 
 creases their surface four times, hut their bulk will be increased cMght 
 times. Kvaporation is projiortional to the surface, but if doubled 
 the quantitj^ reside under a ^ven surface, double the time must ha 
 taken to gasify the liquid, subject to a correction in that the spheroids 
 aie reducing in diameter as the vapor expands. ITence. the import- 
 ance of constructing the nozzle so that it shall dischaigi' ga>oline in 
 as finely divided state as possil)U'. 
 
 i.W(U7— 10 9 
 
130 TENTATIVE MANUAL OF INSTRUCTION. 
 
 Lowered pressure tends to cause vaporization, which be<»ins as 
 soon as the fuel has left the nozzle. It is impossible to measure or 
 esthnate the extent of the vaporization at the nozzle or throu«:h tli^ 
 manifold, due to this pressure reduction, but it is known to be very 
 appreciable in its effect. * It should be considered as a condition af- 
 fecting vaporization at the nozzle end but slightly, but to a much 
 greater extent after the fuel has become suspended in the air. 
 
 Those who have constructed transparent mixing chambers for the 
 observance of nozzle action, have ascertained that the fuel left the 
 nozzle as a solid stream or in heavy globules, not as a fine spray, as 
 it is supposed to do. A good design of nozzle and needle valve will 
 do much to correct this, giving an increase in power output and fuel 
 economy. HoAvever, any nozzle form will give a wet and uneven 
 discharge with low engine demands, even though a true spray may 
 be delivered with increased demands. Some of the fuel torn away 
 is in small enough particles to be considered as spray or mist, and 
 may be taken as contributing directly to the vapor content of the 
 mixture ; the greater part, however, sooner or later strikes some part 
 of the containing walls, and is later picked up in the form of 
 globules. These globules are continually taken up and thrown out 
 by the air stream in its progress to the cylinders, until some of them 
 are sufficiently small to become completely vaporized. 
 
 Whatever form be given to the nozzle, the eifectiveness Avith which 
 it can break up the fuel varies as the difference between the pres- 
 sures at its two ends, and as the pressure difference varies through- 
 out the speed range of the engine, the fineness will vary also. Since 
 the nozzle has a very small opening, even for the largest automobile 
 motors, it is easily stopped up, and the construction shoidd be such 
 that it may be easily removed for cleaning. 
 
 A vapor is the gaseous form of a substance that is ordinarily 
 solid or liquid. The degree of vaporization in the carburetor is the 
 fineness with which the liquid is broken up at the nozzle ; the reduc- 
 tion of pressure within the mixing chamber, and the temperature 
 and grade of the fuel. During vaporization by pressure reduction, 
 that part of the liquid which vaporizes does so through the abstrac- 
 tion of heat from the remainder, which becomes constantly colder. 
 Vaporization due to pressure reduction by engine suction will con- 
 tinue until the temperature of the liquid becomes so low that vapori- 
 zation ceases, until heat is supplied from outside source. Vaporiza- 
 tion by pressure reduction, however, can become only partially com- 
 plete, since the part of the liquid which vaporizes does so through 
 the abstraction of heat from the remainder, which becomes con- 
 stantly colder. 
 
 When a carburetor is rather small for the engine which it has to 
 supply, it becomes very cold while in operation, as the amount of 
 heat necessary to effect the vaporization of the gasoline is more than 
 is available from the entering air or than could be secured through 
 the metal of the carburetor by conduction. The temperature of the 
 metal becomes so low that water condenses on it, and in extreme 
 cases is deposited in the form of frost. This indicates a temperature 
 in the carbureter too low for the successful use of inferior fuel, and 
 so low as to possibly affect the intimacy of the resulting mixture, 
 even if high-test gasoline be used. Moreover, if any water be present 
 in the float chamber, it will probably freeze and disturb the flow of 
 
ELEMENTARY AUTOMOTIVE ENGINEERING LECTURES. 131 
 
 the gasoline. In oixler to overcoiue thi.s, heat is supplied by provid- 
 ing means for lieating the air supj^ly, the mixture, or the gasoline. 
 
 The air may be heated by arranging the outside end of the air- 
 inlet pipe so as to terminate (•h)sely to tlie exhaust manifold or some 
 liot poition of the engine. Tlie mixture may be lieated by a jacket 
 around the mixing chamber, and heat ai)pHed eitlier by means of hot 
 water taken from the cooling system ^vitli a shunt, or by passing the 
 exhaust gases through the jacket, v^imilarly, the licpiid nuiy be 
 heated by hot water or exhaust gases by jacketing the float chamber. 
 
 Heating the carburetor by the circulating watei- gives good re- 
 sults, bnt the starting of the motor is more difficult, especially in 
 winter. Heating by exhaust gases is open to some objection, as oil 
 and carbon soot are liable to be deposited in the healing jacket. 
 
 The fuel charge for a gas engine is composed of a mixture of about 
 10 to It) jniits air to 1 of gasoline vapor. The proi)ortion varies 
 according to the conditions of tiie atmo^|)herc. (jiuility of gasoline, 
 and engine s|)eed. At lirst it was thought tliat tlie best results were 
 obtained with a constant mixture undei- all conditions. However, 
 from experience and numerous experiments, it has been conceded 
 that a constant mixture is not advisable, either from the standpoint 
 of fuel economy or best operation. A constant mixture is one in 
 which the proportion of gas and air does not vary. 
 
 To get the maximum powei' out of a given-sized engine the 
 fuel sliould l)c introduced into the cvlindei- as cold as possible, 
 consistent with t-omplete cxaporation. intimacy of mixture, and 
 completeness of ct)nd)nstion. 
 
 A thin or lean mixture is one having a very small proportion of 
 fuel gas. A rich mixture is one having a greater percentage of fuel 
 L';i-. .\ lean mixture is usuallv the most economical. 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LECTURE VI. 
 
 CLUTCHES. 
 
 < Instruction Cluirls Nos. 1. 2. 4. 20. 21, :{'.). K<iuii.ni.-Mi : White, L)<><lf?e. F. W. I>. 
 
 clutciios. ) 
 
 A clutch is a movable friction couplin*^ for coiiiiccting the crank 
 shaft to the ti-aiisinission shaft. It is so arranged tliat tlie latter may 
 remain stationary with the former in motion until "thrown in,*' 
 whereupon the transmission shaft will tui-n with the crank shaft, 
 '^riie le:i(lin<jf re(|uirements are: (1) (iradual en<i;a<ii'ment, (2) (|uiciv 
 <li^en«ra<rement. (."5) lar<;e friction surface, (4) accessibility, and (5) 
 >imi)le construction. It may be said that the action should be such 
 that it does not apply the full i)ower of the engine at once, but 
 giadually. in ordei- that the automobile nuiy start slowly and with- 
 out jerking. If the i)ower be applied suddenly, the machinery may 
 be badly strained, or again, the resistance of the stationary car may 
 be suthcient to overcome the momentum of the engine and cause it 
 to >toi) between the power strokes. A clutch is not necessary on auto- 
 mobiles propelled l)y steam or electricity, as these powers are moro! 
 Ile.xilile. that' is. the a|)i)lication of ])ower is not intermittent, as witli 
 the ga> engine. .V clutch shoulil disengage promptly in order to 
 avoid any drag of the parts after disengagement. Large fi'ietion 
 .-urfaces are necessary in order that the clutch may be ca))al)k^ of 
 transmitting the maxinuim ])ower of tlie engine to which it is ap- 
 l)lied without slip or loss. This is to axoid waste' of |)owei-. and 
 also render the clutch easy to operate. 
 
 -V clutch sliould be easy of removal for in.-pection or repairs, anct 
 should be provi(Unl with suitable adjustments so that a certain 
 amount of wear between the surfaces may be taken uj) without renewal 
 of surfacing. It should be as sim})le as j)Ossible, of substantial de- 
 >ign and construction, and with as few operating parts, which would 
 l)e liable to get out of order, as is consistent to preserve proper op- 
 eration. Tn the event the parts needing leplacement, or of wear be- 
 ing serious enough to ie(|uire new frictional surfaces, it should be of 
 >uch construction that the replacement could be made with mininuun 
 expense. 
 
 .V cone clutch consists of two meml)er>: A disji-shaped ring, sc- 
 <'ured to the face of the flywheel, and a truncated cone carried by 
 a slee\e sliding on the main shaft, and held in close fit by means of 
 a spring. The first member is called the " fenuile cone" and the 
 sec(»nd the "male cone." There are two varieties of cone clutch: 
 
 133 
 
134 TENTATIVE MANUAL OF INSTRUCTION. 
 
 (1) The fxtornal cone clutch, in which the male cone is forced 
 against tlie Hywheel froiu the rear, and (2) the internal cone 
 clutch, in which the male cone is contained within the other mem- 
 ber, and is foiced into contact from the front. In both forms, the 
 contact is between a metal surface and one of leather or fiber. Since 
 it is essential that no oil or grit be allowed to collect on the friction 
 surfaces, the internal cone clutch is preferable, as enabling the sur- 
 face to l3e more readily protected. Sufficient friction surface, and 
 the proper angle of the cone surface are essential in order to obtain 
 good i)ower transmission. Troubles are sometimes encountered with 
 cone clutches. Unless skillfully liandled, the power will be thrown 
 on with a jerk — not gradually as it should be. The friction sur- 
 faces, when worn, are lial)le to slip. A uudtiple disk clutch consists 
 of numerous metal disks secured alternately to the clutch shaft and 
 to the face of the engine flywheel. The disks are compressed in 
 frictional contact by a strong spring, thus giving a firm driving con- 
 tact for transmitting the power from the engine to the transmission. 
 
 A clutch is said to be " sweet " when it properly performs its 
 functions, that is, when it may be thrown into engagement gradu- 
 ally, thus api)lying the i)ower by degrees, so that the car may start 
 slowly antl without jerking. A clutch is said to be " fierce " Avhen the 
 reverse conditions obtain, that is, when it takes up its work too 
 quickly, causing the car to jump forward with a bound upon start- 
 ing. Dei'angement is often caused by tlie clutch spring being too 
 strong; this results in an unusual amount of power being applied 
 to the clutch [)e(ial in actuating the clutch, and it is apt to stick, 
 preventing a (|uick withdrawal at a critical moment. The tension of 
 the clutch spring should be made less, the friction surfaces cleaned, 
 and a snuill quantity of castor or neat's-foot oil ap})lied to theui if 
 they are. of leather. 
 
 There are sometimes troubles experienced with uiultiple disk 
 clutches. These are subject to three varieties of derangement: (1) 
 Gripping, (2) spinning, and (3) slipping. Gripping is a quick, 
 sharp engagement of the clutch. It may be caused by looseness in 
 the foot pedal or joints, or a "give" in the lever or fulcrum. A 
 gradual clutch engagement can not be secured when the leverage is 
 not absolutely positive. Another cause is a too poAverful spring 
 tension. In a leather to metal contact, gripping may be caused by 
 exhausting the oil in the leather, thereby roughening its surface. 
 Spinning is the continued revolution of the driven member, usually 
 caused by faulty design, poor adjustment or failure to make a com- 
 plete disengagement of the two members. Slipping is usuall}'^ due to 
 a spring tension that is too weak. Another cause is the undue wear 
 of the friction surfaces, allowing the clutch pedal to move backward 
 till it rests against the rear end of the slot in the floor.- 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LECTURE VII. 
 
 TRANSMISSION. 
 
 ( Instruction C'harts Nos. 1, 2, 21, 39. P^quipment : iMxl^e, Wliit^-. F. W. D.) 
 
 The term " transmission," strictly speaking, includes the entire 
 mechanism betAveen the engine and the rear wheels, through the sev- 
 eral parts of which power is transmitted. The gear set is simply a part 
 of the transmission, the drive another part, etc. However, by incorrect 
 usage, the term has come to mean only the gear set. A transmission 
 is necessary on account of the nature of the gas engine cycle. The 
 crank shaft of a gas engine is operated by an intermittent force, and 
 not, as in the case of a steam engine, by a continuous pressure; hence, 
 it will only develop its full power when running at the maximum 
 speed. The duties of a transmission are : The first object is to allow 
 the engine to speed up until the energy which it stores in the fl}- 
 wheel is sufficient to keep the shaft revolving at a speed showing no 
 great percentage of variation. A second and principal duty is to 
 adapt the engine to a heavy load, which, under other circumstances, 
 would cause it to slow down and stall, if required to work under such 
 conditions any length of time. 
 
 It may be assumed (1) that a man is raising a bucket in a well by 
 winding n rope around the drum of a windlass, and (2), that the 
 bucket must be raised a certain number of feet every minute; then if 
 the bucket of water w^eigh such an amount as to require all his 
 strength to fulfill these conditions, and any extra weight added to the 
 bucket would overtax his strength to such an extent as to make fur- 
 ther progress impossible, it is evident that some mechanical contriv- 
 ance is necessary which will enable him to exert the same strength, 
 but apply it through a longer period of time, or through a greater 
 distance. To make this plain, it may be assmned that he wished to 
 lift a barrel weighing 600 pounds 10 feet. It is evident that this 
 could not l)e done in a direct manner. If, however, he should build 
 an incline long enough, he would be able to roll it up, accomplishing 
 the same work, but taking a longer time. Another way of doing it 
 would be by the use of a lever. Now returning to the first illustra- 
 tion, instead of turning the drum of the windlass direct by hand, a 
 gear ma}^ be placed on the end of the drum and constructed to mesh 
 with a smaller gear attached to the lever. To illustrate the principles 
 involved, it may be assuuied that the large gear on the drum is three 
 times the diameter of the small gear. It will, therefore, require three 
 revolutions of the small gear to one of the large gear, and the pres- 
 
 135 . 
 
136 TENTATIVE MANUAL OF INSTRUCTION. 
 
 sure exerted will be only one-third of that required if the crank were 
 fastened to the drum direct. In either case, the work done is the 
 same. To compare this with the conditions of automobile opera- 
 tion, the work required to lift the bucket may be represented by the 
 work required to drive the machine, and the man's effort, or force 
 applied to the lever of the windlass, by the pressure exerted on the 
 piston of the engine. 
 
 Work is the product of two factors: Force and distance through 
 Avhich the force acts. For a given amoimt of work, force and dis- 
 tance are inversely proportional, that is, if the distance be increased, 
 the force will be diminished a corresponding amount. The office of 
 the transmission is to keep the first factor — " force " — within allow- 
 able limits, by permitting the second factor — " distance " — to vary in 
 ]:)roper proportion. The factor " distance " is represented by the 
 distance traveled by tlie piston during the power strokes, and 
 '' force " by the pressure exerted on the piston during these strokes. 
 
 The majority of change-speed gears sets which have been generally 
 fitted to autouiobile service are forms of sliding gear arrangeuients 
 and may be divided into two main classes. In progressive sliding 
 gear sets, but one member is emjiloyed for all speeds, and this is 
 i^hifted along from one extreme position to the other. In the selective 
 system it is possible to go into any one of the speeds, or gear ratios 
 desired, without passing into other speeds, and with but a limited 
 movement of the shifting members. 
 
 The sliding gear system Avas one of the first to receive general ap- 
 ])lication in early forms of motor vehicles and in its primitive con- 
 dition it was but a modification of the back gearing used on certain 
 classes of machine tools, such as lathes, drill presses, etc. One of the 
 advantages of this type, when compared to other gear transmissions, 
 is that it is possible to provide a greater numl^er of speed changes and 
 that there is a higher driving efficiency when on the lower ratios be- 
 cause but two i)airs of gears are in mesh. 
 
 With the selective gear set, the nmnber of shifting members pro- 
 ^ided makes it possible to go into any speed directly without passing 
 through the others. For instance, if it is desired to engage the high 
 speed, this member may be pushed directly into position, so that the 
 main shaft, and the constant drive gear are locked together. If it is 
 desired to go into reverse, a simple movement of the operating, or 
 shifting member, which is guided by an H slot gated segment, will 
 disengage the high speed and throw the other shift member into 
 position. 
 
 One of the advantages of this method is tliat it is easy to engage 
 the gears and that the liability of injurying the gear teeth by inju- 
 dicious shifting is not as great as in the progressive type. Another 
 advantage of the selective .system is that it permits a more compact 
 construction and makes possible the use of shorter shafts which are 
 stitl'er than longer ones because the distance between points of sup- 
 jiort is not so great. Not only is th^ operation much easier, but it is 
 })ossib]e to obtain the varying speed ratios nmch more quickly than 
 with the })i'ogressive system. 
 
 The usual number of gear ratios jjrovided is three forward sj^eeds 
 and one reverse motion. On some of the heavier touring cars four 
 forward speeds are provided, as in the White gear box, and when this 
 
ELEMENTARY AUTOMOTIVE KXGIXEERING LECTURES. 137 
 
 is (loiio. (Mij^iiiecrs dirt'cr as to wlu'thci' the direct drive slionld l:e on 
 tho third or fourth ratio. When the direet drive is on tlie third 
 ratio, the fourth speed is ohtained hy <re:irin^-ii[) and the (hivin«r 
 <liaft revolves fastei- than the main siiaft of the en<>ine. When the 
 fourth speed is a direct (hi\('. tlic crank shaft and tlie drivino; shaft 
 tui'n at the same speed. The ^I'Mred-iip fourth speed can he »is<h1 only 
 wlien conditions are exceptionally favoralile to iiiirh s[)ee(h If the 
 liigliest speed \vas ohtained l)y a direct (hive tlie natural tencU'Ucy of 
 tlie motorist woidd he to use this most. I»ut there would l)e many 
 conditions where the ratio woiihl he too liijih and one of tlie lower 
 ^eais Would have to he used. If the direct drive was ohtained in the 
 third ratio this would he employed the jrreater part of the time, and 
 as there would he less wear on the <2:earin<r with the direct drive en- 
 ga«red. it would be preferable to use this as much as possible. 
 
 The (|iH'stion of which <rear ratio to use depends entirely upon 
 local conditions, and before deteruiinini>- the ratios of the geariiiii" in 
 the speed-chauirinir mechanisms, it is imjierative tiiat a definite rela- 
 tion lie eslaltlished between the speed of the drivinu' shaft and the 
 road wheels. When heavy pleasure cars use engines of moderate 
 ])Ower, the gear I'cduction is usually three and one-half, or four, to 
 one. this meaning that when the gearing is in the direct drive the 
 engine crank shaft will turn three and a half, or four times to one 
 levolution of the diiving wheels. On cars where the margin of power 
 is large and where high speeds are desired, the i-atio may be but two 
 aiHJ one-half to one. If the car is geared too low. the engine must 
 make a very high number of revolutions when on the highest speeds 
 and u>e much more fuel than ni'cessary. On the other hand, if the 
 driving ratio is too high it will be necessary to change gears fre- 
 <|uently, because even moderate grades will make it imperative to use 
 a lower ratio than that atforded by the diicct drive. There is con- 
 >i<h>rable friction in the ordinary gear box. even when the high speed 
 is engaged, because of tlu' constant rotation of the countershaft in its 
 bearings. 
 
 The body fitted to the car has a material beai'iug upon the gear 
 ratios provided. The dri\ing si)eed that would be entirely practical 
 on a chassis fitted with a roadster body, would be much too high if a 
 limousine, or coupe, body was fitted to the same chassis. If the oar 
 is to lie operated in regions where the conditions are not favorable, 
 such as hilly sections, or where the highways are poorly developed, a 
 much lower final drive ratio must be pro\ided than where the roads 
 are good and conditions favorable to high si)eeds. The speed ratios 
 when the low gears are engaged will vary from ten to one to such 
 txtit'ines as twenty-live to one. The inteiniediate speed usually 
 \aries from Wvi} to one. to ten to one. and a third ratio in a four- 
 speed gear set may vary from three to one to six to one. and in some 
 gear sets it may have a value of seven, or eight, to one. If the fourth 
 vspped is obtained by gearing-uj) one may get a ratio of <lrive as high 
 as two to one. though when the direct drive is on the fourth speed it 
 is seldom higher than three to one. Most of the sliding gear sets have 
 at least oiii' of the speetls a direct dri\e. i)ut some forms have been 
 devised wlu'ie the |)(»\\('r is transmitted through geai's at all ratios. 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LECTURE VIII. 
 
 THE DRIVE. 
 
 ( llistl'llcti'ili ni;il|s .\(»s. 1. L'. L'li, L!7. .■>'.». K(| lli | Ulirlil : I»(Mli:r. Wliilt". (';lililliU 
 
 drive shafts.) 
 
 Ill tlu> I I'aiismis^ion of power lo llir (Inxiiiii' wliccU of ;in mitoino- 
 bile several methods are followed. These vnrv aecordino- to the size 
 and weight of the veliiele and the eharactei- of the en«rine, also ac- 
 (•ordin<i: to the indixdiial ])i'eferenee of the designer. One system is 
 l)i('fei'ied to another on acconnt of real or supposed reliability, its 
 etlifieiicv in cc ononiizino- jjower. I'tc. The types of drive in fjenei'al 
 ns(> are the shaft, the chain, and the si)nr drive. In the shaft drive 
 method, powei* is transmitted from the fz^';\v box to the real- axle 
 by a i)i-opeller shaft, 'j'he eniiine is generally i>hiced at ri<rht an<rles 
 to the axle: it is therefore iieci's^ary to chanjie the direction in which 
 the power acts. This invol\("~ the n>c of bevel ironrs at the rear axle. 
 
 A in)i\ci-.al joint i> :i c()ii])lii>Li' fcr joininjj: two shafts or pai'l-- of 
 a machine endwise, so that one ina\' i^'ivc rotai'y motion to the othi-r 
 when formini:' :>ii ai^^h' with it oi' may moxc freely in all directions 
 v.ith I'espect to the other. l'ni\"ersal joints are necessary to allow 
 the >haft to turn freely, e\'en th(:u<>h it may not be in line with the 
 shaft j>rojectin<r from the irear box. It must \)v remembered that 
 the entiine and gear box are mounted on the frame and that there are 
 sprinir> interpo.stMl b(>tween the frame and the axles, hence when 
 the latter \ibrate up and down the rear end (d' the ])ro|)eller shaft 
 moves also. 
 
 There are two types of shaft drixc -one in which the proixdh-r 
 shaft is placed at an a«rli' with the other shaft >ections. and one in 
 which the several jiarts are in line. The strai<>ht line drive is the 
 mime ^riven to the latter and has ad\anta<:es on acconnt of rediicinir 
 friction and Avear due to the angularity at the miixersal joints. It 
 is constructed so that when the car is loaded tlu' pi-o|)eller shaft is 
 in direct line with the crank shaft. I'nder these conditions the 
 dri\(' is accomplished in a straight line, which assinvs the delivery 
 of maxinnim ]K)W('r of the engine to the rear axle. On accotint of 
 the action of the supporting springs a univeisal joint is neiessary, 
 as the shaft sections are not in line when the car is light or in motion. 
 
 .V torsion rod is a rod attached rigidly to the housing or casing 
 of the rear axle and fastened to a crosspiece on the frame neai- the 
 transiidssion. Its object is to prevent the tui'ning of the housing 
 due to the thrust of the drixing bexcl. 
 
 ]:',!» 
 
140 TENTATIVE MANUAL OF INSTRUCTION. 
 
 A radius rod is a device designed to prevent any forward or aft 
 movement of the rear axle, which, on account of the flexible action 
 of the springs, may be caused by an obstruction in the road. Thus, 
 if one wheel should sti'ike heavy sand while its mate is on good 
 surface the rear axle will be throAvn out of line with the drive and 
 bring undue strains on the latter. To prevent this i-adius rods are 
 attached to the axle near the ends and" pivoted at some convenient 
 place on the frame. The axle, while free to rise and fall, is held at 
 right angles to the drive. 
 
 There are two types of chain drive in general use, the single and 
 the double. Tn the first method there is a chain and sprocket con- 
 nection from the main shaft direct to the differential on the rear 
 axle. A doul)le chain drive has a separate chain for each rear wheel, 
 driven from a transverse jack shaft, which, in turn, is dri^^en direct 
 from the engine and carries the differential. The double chain drive 
 construction is found on pratically all heavy cars using chain drive. 
 Briefly, the system includes (1) a transverse center divided jack 
 shaft driven direct from the engine or through the transmission 
 gear by bevels to the differential, (2) a sprocket at each end of 
 the jack shaft for providing chain connection to the hub of each 
 rear wheel, and (H) driven Avheels turning loose at the ends of a dead 
 axle, each being driven by a separate chain on a sprocket secured 
 to its hub. 
 
 The disadvantage of the chain drive is principally the chain, which 
 is an objectionable mode of power transmission, especially under 
 conditions of automobile operation. There is an additional compli- 
 cation of jack shaft, sprockets, etc., involving extra friction and w^ear. 
 The chain drive is objecticmable, as its use is accompanied by noise, 
 excessive wear, imj^erfect engagement with the sprocket teeth, and 
 poor efficiency due to inherent defects and conditions of service. M. 
 O'Gorman, a pi'ominent engineer, before the British Society of Arts, 
 has credited the shaft drive with (V,) per cent efficiency, and the chain 
 drive with two chains and a jack shaft Avith but 50 to 58 per cent 
 efficiency. The gradual displacement of chain drive by the shaft 
 drive is evidence of the superiority of the latter. The chain should 
 operate in oil, in a dust-tight case. The advantage of the chain drive 
 is that a greater ])ortion of the weight of the drive mechanism is sup- 
 ported by the frame instead of the rear axle housing: it is thus 
 cushioned from shocks due to uneven road. 
 
 A roller chain is composed of a series of rollers, known as center 
 blocks, joined by side links. Each roller rotates loose on a hollow 
 core which is turned to smaller diameter at either end, to fit a per- 
 forated side piece joining the rollers into pairs. The side links are 
 set over these side pieces and bolted in place through the cores, and 
 in operation the rivets of a chain act as a number of auxiliary shafts 
 and operate under friction in the same manner, but with less favor- 
 able conditions than the shaft that drives them. A chain can never 
 be in true pitch with its sprocket. A ])air of spuv gears tend to a 
 certain extent to wear into a good running fit with each other, but a 
 chain, if nuule to fit its sprocket when new, does not continue to do 
 so a moment after being made, as wear at once throws it out. This 
 being so, it nuist be put up witli, and involves the consequence that a 
 chain can only drive with one tooth at a time, sup])lemented liy any 
 
etj:.m[:xtary ai'tomoth'e engineering lectures. 141 
 
 frictional "bite" the otlici' linUs may 1k»vi> on the base of thi- tooth 
 interspaces. If tlie chain be made to fit these accurately, takinir a 
 roller chain for illustration, it is obvious that the least stretch will 
 cause the rollers to be^in to ride on the teeth. If, however, the 
 teeth b(> made narrow, compared with the spaces between the rollers, 
 a considerable stretch may occur without this taking place. The 
 roller inteispaces, then, shoidd be lonir. to permit the teeth to have 
 some ])lay in them, while retaininfr sufficient strenfrth. 
 
 In order that the driviufr sprocket may receive each incoming link 
 of the chain without its ha\in<^ to slide up to the tootli face it should 
 be of a somewhat lon<ier pitch than its chain, the result beino: that the 
 bottom tooth takes the (lriv(>. this l)ein<i: permitted by the tooth ])lay. 
 This ditl'erence. of course, <i:radually disa]ipoars as the chain stretches. 
 The i)ack wheel sprocket, on the othei- hand, should take the drive 
 Avith its to]>most tooth, and hence should be of sli<rhtly less pitch than 
 the ( liaiu. ImiI as the pitch of the latter constantly increases, it may 
 l^e ori«riually of the same ])itch. The only riMiiaininj; point witli 
 regard to desii>n. and one which the owner of the car may easily 
 insure, i- that the numlxT of teeth in the sprockets l)e jirime to that 
 of the links in the chain. 1'he cause of (he sua]) and rattle of a chain 
 is that I'ven with tlu' best desiirned sjjrocket, as each tooth in turn 
 passes out of eniraj.''ement with the chain, the next roller nuist be 
 drawn forwar<l throuGfli an ai)]>reciable distance before engagino; a 
 tooth. Tliis acti«)n not only i)roduces the noise luit is an im])ortant 
 factor in waste of drivin<r power. 
 
 In order that chains have the ])ro])er attention the ])rincipal ])()ints 
 to be observed in the use and care of sprocket chains are: (1) To 
 maintain tlu' proper tension in order to avoid "whippinir" — which. 
 ])artii-ularl\ witli a lonji one. is liable to residt in snai)pin£r of the 
 chain — and. at best, involves a lo.ss of driAinir efficiency. The chain 
 should not be drawn too tijrht. Some slack must always be allowed. 
 (2) The sprockets should always be kept in ali^mnent. In the case of 
 a double chain drive, from a counter shaft parallel to the rear axle, 
 care .should be exercised to maintain the parallelism, even preferrinof 
 a somewhat loose chain to a ti<rht one that strains the countershaft. 
 {'■^) If a link sliows si<rns of elon<rati()n, it should l)e re])laced by a 
 new one. (4) "Whenever the chain is removed foi- cleanint!: <'i" other 
 ])ur]:>ose, it must be carefully replaced, so as to run in the same direc- 
 tion as formerly, and with the same side U]). The chain should never 
 be turned around, or its direction between the sprockets reversed. 
 (5) A new chain shoidd not be i)Ut on a much-worn sjirocla't. ((V) A 
 chain shoidd be fre(|uently cleaiu'd and rtibbed with efraj^hite, because 
 the chief difficulty iji\oh(>d in the use of drixinir chains is the lia- 
 bility to clojr and <rrind with sand. dust. etc. (7) .Vfti'r steadv use 
 fo!' a more or less extended ix'riod. the chain shoidd be renK)ved and 
 cleaned throufrhoiit. 
 
 A chain may l>e best cleaned, after reiiio\ inii- it from the sj)rockets. 
 by cleaninc: first in boilincr water, then in gasoline, in order to remove 
 all urease and dirt. A common ]iractice is to boil the chain for 
 about half an houi- in mutton tallow, which forms an excellent inside 
 lubricant. After boilincr. the chain is hiin<i' up until iliorouirhlv cool, 
 at which tim(> the tallow is hardened. It may then be wi])ed off clean 
 and treated with a ])reparation of <rra])hite, or a irraphite alcohol 
 .solution on its inner surface. Some authorities recommend that the 
 
142 TENTATIVE MANUAL OF INSTRUCTION. 
 
 chain, after it is cleaned in looiling water and gasoline, should he 
 soaked, first, in melted paraffin for an hour at least, and then in a 
 mixture of melted mutton tallow and graphite. After each soa king- 
 it is dried and wiped clean. With either process, a daily application 
 of graphite is desirable. 
 
 It is not necessary that both chains be of ecjual tightness, as the 
 diiferential gear on the jackshaft will counteract this and cause each 
 chain to do its share of the driving. The jackshaft and rear axle 
 should be made parallel by adjusting the radius rods to secure the 
 proper engagement of the chain with the sprockets. 
 
 Transmission of poAver by spur gears, as from engine shaft to 
 diiferential drum, or to an external or internal gear on each of the 
 rear wheels, is, in some respects, desirable. The drive between spurs 
 is steadier, and is attended by smaller loss of power than between 
 chains and sprockets, or bevels. 
 
 A number of designers have used worm gearing in connection 
 with shaft-driving systems instead of the bevel gears so generally 
 adopted. The advantages of the worm gear are more apparent in 
 motor-truck construction than in pleasure car practice, though it has 
 been used to advantage in both classes of vehicles. A high degree of 
 efficiency has been obtained by using woruis of peculiar tooth forma- 
 tion which have a spii-al angle often approaching 45 degrees. Such 
 worm may have froui (J to 10 or I'i threads, and they are perfectly 
 reversible, when contrasted to the single threaded worm used in 
 steering gears, which are an irreversible forui. Obviously the worm 
 employed for driving an automobile uuist be perfectly reversible to 
 be practical, as very often conditions will be such that the rear 
 wheels and worm gear to which they are attached nmst turn the 
 Avorm and driving shaft, as in descending hills, with the rear axle 
 overrunning the engine. 
 
 This forui of gearing oifers many inducements and has positive 
 advantages Avhich counnend it as a means of direct final drive. Any 
 range of reduction that would be likely to be needed may be obtained 
 with but a single pair of worm gears, and I'eductions of 20 to 1 may 
 be as easily accomplished as securing the higher ratios Avithout the 
 efficiency of the combination being affected. It Avould not be possible 
 to obtain as Ioav speed reduction as possible Avith worm gearing by 
 the use of a single set of bevel gears or a single pair of sprockets and 
 chain connections, because the driven member would have to be of 
 such large size that it Avould be difficult to place it within the confines 
 of an ordinary axle. 
 
 Among sonie of the advantaoes advanced in favor of Avorm gearing 
 may be cited: It is silent in operation; Avhen properly designed it 
 will transmit 85 to 90 per cent of the engine poAver to the rear Avheels 
 on direct drive, and it is extremely enduring. Its efficiency mrder 
 ideal conditions is equal to the most accurately machined and finely 
 adjusted bevel gearing, and instead of the efficiency becoming less 
 as the gearing Avears, it actually becomes more silent and freer run- 
 ning with use. .1^''-: 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 LECTURE IX. 
 
 THE DIFFERENTIAL. 
 
 (Instruction Chiirts Nos. 2, 12. 2<i, 27. Iviuipnit'iii : l)(Mly;e, Wliito. ) 
 
 When ;i (III- )i:i\i'ls ;u(»im(l ii ciuvimI path, the distance traveled 
 liy the outside wheels i^ i:ri';tter than that ti'aveled by the inside 
 \vjieel>. As the flout w hi'el- are lou.se <Mi the axle, thev can turn at 
 • litlcrent rates to eonipi'usate lor this di tt'erenei'. Sinee holh fear 
 wheel- are driven l)y the euii'in.e. it is ne«v>sary to apply a devici' that 
 will permit them to i-otate at dill'ereut speeds, and receive an e:|ual 
 di\ i^ion of the powei'. To aecomi)lish this, a system of ireiirs. called 
 the dirt'erential. is i)ro\ided. The ditlV'rential may be delnied as a 
 -y>tem of ^-ears, which |)ermits one wliee} tp traxel independently of 
 the other while ^oin<>' around a curve, so that the outer wlieel may 
 acconunodate itself to the lon<ier path it has to travel. 
 
 Tlu'ie are thiee types of di tl'erential in <reneral use; the l)evel. the 
 -pur dirt'erential, and worm. The bexel type is the ori<j:inal form 
 and is larj^i'ly used. The si)rocket or drive wheel has secured to its 
 inner rim se\eral studs earryinji" bevel pinions, which, in turn, en- 
 ilt\}iv a bex'el <rear wheel on either >ide of the s])rocket. I'hese <i"ear 
 wh.eels. la-t nu'utioned. are riiiidly attached on either side to the 
 inner end- of the centi'r dixidi'd axle bar. one si'rvin«i" to turn the 
 left wheel, the othei- the ri<iht. \\'hen power is applied to the 
 -procket. causiuii' the vehicle to move strai«rht forward, it may bj 
 readily undeistood that thi> bevel piiuons. secured to the sprocket, 
 instead of rotatiuii'. which would mean to turn the tlrive wheels in 
 o])p<'site directions, remain motioidess. actin<i simply as a kind of 
 lock or clutch to secure uniform and continuous rotation of both 
 wheels. So soon as a movement to turn the vehicle is made, at which 
 time the wheels tend to move with dill'ereut speeds, the resistance of 
 the wheel nearer the center, on which the turn is made, tendin*; to 
 m;d<e it turn more slowly than the other, as may be observed, these 
 piidons beiiin rotatine; on their own axi's. riius. while allowinjj: the 
 pivot wheel to slow up or ri'iuain stationary, as conditions may re- 
 «|uire. they continue to urtre forward the other at the usual speed. 
 
 The princii)les upon which the opeiation of the dirt'erential de- 
 j)eud- may be expressed under four heads: (1) ^^'hen the resistance 
 «>fl'ered by the two drive wheels and attached ^ear is the same, as 
 when the car is driven forward, the pinions can not rotate. (2) when 
 the rt'sistance is (rreater on one wiieel than on the other, they will 
 rotate correspondin<rly, althou<2:h still moving' forward with the 
 wheel offerinir the le-ser re-i-tance. ( ."> ) the pinion- may rotati' inde- 
 
 1 1:; 
 
144 TENTATIVE MANUAL OF INSTRUCTION. 
 
 pendently on one gear \vheel. -while still acting as a clutch on the 
 other giving sufficient power to carry it forward, and (4) if a re- 
 sistance be met of sufficient poA\er to sto]:) the I'otation of both wheels 
 and their axles, the condition would affect the entire mechanism, 
 and the pinions would still remain stationary on their own axes. 
 
 For liglit service the sprocket or spur tlrive generally carries two 
 pinions, as shown in the chart, but in hirger vehicles the number is 
 increased to three, four, or six and the size, pitch, and number of 
 teeth are varied, according to requirements. Of course, it is essen- 
 tial that the equalizing gears be properly chosen for the work they 
 are to perform, in the matter of the number of pinions and their 
 teeth, as w^ell as of the metal used, on account of the great strain 
 bi'ought to bear on them. 
 
 In the spur differential, the theory of compensation is the same 
 as with bevel gearing; a divided axle, or jack shaft, whose two inner 
 ends carry gear wheels cut to mesh with pinions attached to the 
 sprocket pulley. These pinions are, however, set in geared pairs, 
 Avith their axes at right angles to the plane of the sprocket. The 
 pinions of each pair are set alternately on one side or the other of 
 the sprocket, meshing with one another in about half of their length, 
 the remainder of each being left free to mesh with the axle spurs on 
 the one or other side. With some differentials, the divided axle car- 
 ries internal gears, with others, true spur wheels. The operation is 
 obvious. AVhen the veliicle is turning, one rear wheel moAcs less 
 lapidly, causing the pinion on Avhich it is geared to revolve on its 
 mate, which, in turn, revolves on its own axis, although still engaging 
 the gear of the opposite and moving wheel of the vehicle. 
 
 The action of the differential pinions may be clearly understood 
 by reference to the chart and giving due consideration to the follow- 
 ing principles : The same resistance at the point of contact between 
 the driving wheels and the ground prevents the pinions from revolv- 
 ing on their own studs, and in this case they are carried around by 
 the supi)orting members and the ring gear. If the resistance upon 
 the right axle shaft is greater than that on the left axle shaft, the 
 ring gear will rotate forward with the wheel offering the least resis- 
 tance and the differential pinions will turn on their studs and run over 
 the surface of the gear which tends to remain stationary, this being 
 the one against which there is the greatest resistance. The differen- 
 tial pinions can thus turn independently of one gear wdieel and run 
 oA-er its surface without turning it, and at the same time act as a 
 clutching member of sufficient capacity on the other gear and axle to 
 ("irry them in the same direction as the ring gear and at a ratio of 
 s[)eed which will depend upon the difference in resistance between 
 the driving members and the ground. 
 
 While the differential gear described is of the bevel pinion type,, 
 other forms have been devised in which the differential action is 
 obtained by means of spur gearing which utilizes the same principle 
 of compensation. The differential gear whicli utilizes bevel pinions 
 IS the form that is more generally used. The differential gear is 
 usually incorpoiated in the rear axle if the drive is bv shaft, and in 
 the countershaft if transmission is by means of side chains. The 
 construction of typical differential gears and l)evel-driving gear as- 
 sembly is shown in the chart: the former is utilized on light vehicles 
 
ELEMi:XTAllV AUTO .MOTIVE EXlilNEERlNG LECTUKES. 145 
 
 and is mounted on flexible roller bearings, while the other construc- 
 tion is a tyi)e more suitable foi- heavier cars and is mounted on 
 tapered roller bcarin<;s. 
 
 A worm ireariuii- in connection with shaft driving systems instead 
 of the bevel «>jears is used, and is very ellicient. The advantai2:e> of 
 the worm <rear are more a[)parent in motor-truck construction than in 
 pleasure-car jn-actice. thoujih it has bocn used (o advantage in both 
 classes of vehicles. A hi<ih degree of etliciency has been obtained by 
 using worms of peculiar tooth formation which have a spiral angle 
 often api)roaching b") degrees. Such worms nuiy have from to 10 
 or 12 threads, and they are perfectly reversible, when contrasted to 
 the single-threaded worm used in steering gears, which are an irre- 
 versible form. ()b\iously the worm emj)loved for driving an auto- 
 mobile must be perfectly reversible to be practical, as very (dti'n 
 conilitions will be such that the rear wlieels and worm gear to which 
 they are attached must turn the worm and driving shaft, as in de- 
 scending hills, with the rear axle overrunning the engine. 
 
 This form (ff gearing otters many inducements and has positive ad- 
 vantages which conunend it as a means of direct final drive. Any 
 range of reduction that would be likely to be needed may be ob- 
 tained with but a single pair of worm gears, and reductions of "20 to 
 1 nuiy be as easily accomplished as securing the higlier latios without 
 the efliciency of the combination being affected. It would not bo 
 possible to obtain as low speed reduction as possible with worm 
 gearing by the use of a single set of bevel gears or a single pair of 
 sprockets and chain connections, because the driven memlier would 
 have to be of such large size that it would be dithcult to place it 
 within the confines of an ordinary axle. Tt is for this reason that 
 most motor-truck manufacturers use a combined bevel gear and 
 chain drive and a double reduction of speed between tlie engine and 
 the rear wheel. 
 
 Among .some of the advantages advanced in favor of worm gear- 
 ing may be cited: It is silent in operation; when properly designed 
 it will transmit 85 to 90 per cent of the engine power to the rear 
 wheels on direct drive, and it is extremely enduring. Its efficiency 
 under ideal conditions is equal to the most accurately machined and 
 finely adjusted bevel gearing, and instead of the efficiency becoming 
 less as the gearing wears, it actually Ik-couics more silent and freer 
 running with use. 
 
 ISIany of the more progressive manufacturers of motor trucks are 
 using the worm and wonn-gear drive. It has been used with suc- 
 cess in pleasure-car applications, but its greatest field of usefulness 
 will undoubtedly be the commercial vehicle industry because of its 
 undoubted sui)eriority over all other forms of gt>aring from which 
 considerable reductions in ratio are demanded and where tlu? effi- 
 ciency of the transmission system should be conserved as much as 
 possible. A tyjiical worm-gear asseml)ly and the method of mount- 
 ing the w(jrm in connection with the shaft (Ui\(' is .shown in the 
 chart. 
 
 The arrangement of a worm-gear driving axle is outlined in the 
 chart, with all parts shown. It will prove useful in showing the 
 actual relation (d' the \arious [)arts to each other. The woini is 
 
 130647—19 10 
 
146 TENTATIVE MANUAL OF INSTRUCTION. 
 
 mounted above the worm gear and is supported by two single-row 
 ball bearings of the annular type which take the radial stresses. As 
 there is also a large end thrust, due to the angle of the worm teeth, 
 it is necessary to use a double ball-thrust member at the rear end of 
 the worm to take the end thrust which is present whether the worm 
 gear is being revolved to drive the vehicle forward or backward. As 
 will be seen by the longtitudinal sectional view through the rear con- 
 struction, the worm-drive assembly is used in connection with a 
 live axle, and the worm gear is attached directly to the case which 
 houses the differential gears. The differential assembly is supported 
 on large single-row annular ball bearings, while end-thrust bearings 
 of the ball type are provided to hold the differential assembly in 
 place positively so that the worm and worm wheel can not be forced 
 out of correct engagement by the end thrust existing on the worm 
 ^ear. The drive from the differential to the wheels is by conventional 
 live-axle shafts. 
 
ELEMENTARY AUTOMOTIVE EN(JINEERING. 
 
 LECTUKE X. 
 
 RUNNING GEAR. 
 
 {Instruct ion ('h:irts Nos. 1, 2, 22, 23. 24. 2.1, 20, 27. 29. ;{!». 40. 41. 42. Kcinip- 
 ment : Dodgo, White trucks.) 
 
 Till' tiMiii rmiiiiiio- ovar incliidos siicli parts ii.>^ tlio tr;uno. spring.s, 
 ;)\los. wlu'ols, hi'akcs, and stinMing: <iear. In early con.struction. aiito- 
 in()l>iK's wero built with some form of underfranu'. whose essential 
 elements were "perches"' connectinof the front and rear axles, as in 
 most horse carriages, and some form of swivel joint to [)ermit of 
 considerable distortion, \n compensation for nnevenne.ss on the road- 
 way. The two objects sought in this suj^jiosedly necessary structure 
 wiMi' strength and flexibility. Many designers used complicated 
 forms of steel tubino-. with the additional object of securing lightness. 
 These elements ha\e since been almost entirely abandoned, except in 
 a few light steamers and electric wagons, for designers learned by 
 c'xperience that with in'o[)erly arranged springs an automobile can be 
 strono; and flexible, without perches and swivels, and light without 
 steel tubing. 
 
 The modern frame consists of a rectangidar frame, built of steel 
 (•hannels, suitably braced, and having several cross members. At- 
 tached to the ends are springs designed to absorb the vibration and 
 shocks. The springs generally used are known as the "' leaf spring," 
 and consist of several layers of steel plates or leaves slightly bent, so 
 that, when laid together, they form a series of superimpos{>d arcs. 
 It is imjiortant that the line of the arc formed by the spring be 
 carefully followed from end to end of each ])late, and that no attempt 
 be made to straighten or bend back the extremities of the longest 
 leaves. This is true, becau.se the spring effect is derived from the 
 temjier of the metal in permitting the load to flatten all the arcs at 
 once under a single stress, which invohcs that thev should slide upon 
 one another in altering their shape, as could not be the case were 
 there anv departure from the line of the arc. 
 
 The elli|)tical, the semielli])tical, and the three-(|uarter ellipti«al 
 are. three forms of sjirings used. The ellij^fical spring is formed by 
 connecting two semielliptical or arc-shaped. springs at their extremi- 
 ties- —generally by bolts i^assed through perforated bosses formed at 
 the ends of the longest leaves — and is attached to the apex of each 
 arc by clips, or nuts. The semielliptical sjiring consists of a segment 
 f(»rmed bv a number of leaves or ])lades ami is ai'ranged to be attached 
 
 147 
 
148 TENTATIVE MANUAL OF INSTRUCTION. 
 
 at the bottom and two extremities of the arc. The three-quarters 
 elliptical spring diffei's from the semielliptic in having one extremity 
 of the arc i-olled up and turned in\Yard. It may be attached by a 
 link or a shackle to a flat or semiellipticle spring — forming a '" scroll 
 elliptic '' — or to the body suspended above the axle. Resistance and 
 resilience are essential in a good spring. AVhile a spring should be 
 calculated to give sufficiently to absorb-the jars of travel, it should 
 not be so resilient as to rebound with a series of vibrations. A shock 
 absorber is a device for insuring the gradual return of a spring to its 
 original shape after being compressed, so as to deaden its rebounds 
 and after movements by absorbing them with some form of frictional 
 resistance. 
 
 A torsion rod is a rod rigidly attached to the housing of the rear 
 axle, and flexibly fastened to a cross member of the frame near the 
 transmission. A second form of torsion rod is a modified construc- 
 tion consisting of a cylindrical sleeve, enclosing the propeller shaft, 
 and attached rigidly to the bevel gear case; it is pivoted at the other 
 end of the frame, or carried by a l)earing on the shaft. A torsion rod 
 resists the torque or twist due to the thrust of the propeller shaft 
 pinion, which tends to cause the housing to revolve. 
 
 A radius rod is a rod used with a chain drive to resist the i)ull of 
 the chain and maintain the rear axle at a fixed distance from the 
 jack-shaft. A torsion rod resists the twist on the gear member, due 
 to the action of a shaft drive, while a radius rod resists the thrust on 
 the rear shaft caused by chain drive. With chain drive, the radius 
 rod describes an arc, as the axle rises and falls in travel. With shaft 
 drive, a slip joint on the shaft is sufficient to compensate iov the 
 varying angle of the shaft. 
 
 The distinction between a '' dead '' and a " live'" axle is that a dead 
 axle does not turn; a live axle turns with the wheels. A semi-floating 
 axle is one in which the wheels are secured directly to the transverse 
 rear axle ; it not only sei'ves to turn the wheels, but also to support the 
 weight of the car. A floating axle is one in which the wheels have u 
 bearing entirely upon the rear axle housing, so that the weight of the 
 car is carried entirely by the housing. The axle in this consti'uction 
 serves only to transmit the motive power to the wheels. 
 
 Automobile wheels should have the following qualities of construc- 
 tion: (1) They must be sufficiently strong for the load they are to 
 carry, and for the kind of roads on Avhich they are to run. (2) They 
 must be elastic, or so constructed that the several parts — hub, spokes, 
 and felloes, or rims — are susceptible of a certain flexibility in their 
 fixed relations, thus neutralizing much vibration, and allowing the 
 vehicle greater freedom of movement. ])articularly on short curves 
 and when encountering obstacles. (3) They must, furthermore, be 
 sufficiently light to avoid absorbing unnecessary power in moving. 
 (4) They'must be able to resist the torsion of the motor, which always 
 tends toproduce a tangential strain. This is the reason why tangent 
 suspended wire wheels are used on automobiles, instead of the other 
 variety, having radial spokes. (5) They must have sufficient adhe- 
 sion to drive ahead without nnduly absorbing power in overcoming 
 the tendency to slij) on an imperfect road. The importance of the 
 last two consi<lerations may be readily understood, in view of the 
 fact that the wheels receive the driving"power direct, instead of being 
 merely rotating supports, like the wheels of horse-drawn vehicles. 
 
Kr.l■;.^rEXTARY automotive engineering lectures. 149 
 
 The aj)pn)Vi'(l lvi)e of mIu'oI is (he wooden, oi- so-called " aitillerv 
 Avheel." 
 
 Tlie slitrlit inclination of tlie si)okc> fiom the outside plane of the 
 rim inwardly, so as to make tho whotd a kind of Maltencd cone, is 
 called " disliin<r.*' The advantage of this constrnction is that it trans- 
 forms the sj^okes into so many sprin<>s, possessing elastic ])roperties, 
 and renders the wheel cai)al)le of bein*^- deformed nnder sidewise 
 stress. The shocks of collision with ohslach-^ ai'c thus distrihnted 
 thron<jfh the tlexihly connected j^arts, ms could not lie the ca>e if the 
 wheel were made in one piece, or on one |)lane. and the con.se(|nent 
 NNcar and strain is o;ivatly reduced. 
 
 The larger the wheel, the smaller tlie -liock> experienced in jjas." 
 iuiy over ine<|ualities in the road. Thus ii is that a wheel T) feet in 
 diameter will sink only (me-half inch in a rut 1 foot wide, while 
 a ;)()-incli wheel will sink nearly thrt'c times as dee)), with the result 
 that the lesilicncy of its tires must be much lar«;er. in order to com- 
 jiensate for the <2:reater shock exi)erienced. The laraer wheel also 
 rises less (luickly over obstructions. There are. however, other 
 methods for neutralizino: the shocks on rouah roads. The end of 
 oiitainino; a low and easy rnnninc: riii" may be achieved (|uite as well 
 by increasing- the lenoth of the vehicle, the lenjjth of the spiinp:.s, 
 and the size of the tires, as by addinj>- to the heiiiht above the <>round. 
 Also, the broad tire is superior to the narrow one in the \ery same 
 particidar — that it will not sink so ((uickly into mud and sand, and, 
 by its greater bufKng properties, neutralizes the concussion other- 
 wise experienced Avith small wheels. These and other considerations 
 have largely determined the pre\alent i)ractice of using wheels of 
 moderate diameter for automobiles. 
 
 77/V'.s'.— IMres are used on anlomobiles. motorcycles, and a large 
 number of horse-drawn vehicles, to secure a desiralile sjning et!'ect 
 or cushion, so as to reduce vibration to a minimum, and to obtain a 
 large traction area to prevent the wheels sinking in soft loaihvay. 
 
 The most etlicient shock-al)sorbing medium is c< nii)ressed air. 
 This method of reducing vibration, however, as exemplified by the 
 pneumatic tire, has the disadvantage that rubber, which is the only 
 elastic air-confining substance available, is liable to puncture. 
 
 Thei'e are in general use three varieties of tire: Solid, cushion. 
 an<l i)neumatic. As is generally known, the |)neumatic tire was first 
 tlevised in order to furnish the needed resiliency in bicycles, and for 
 the same jiurpose it has l)een found useful in au<omo])ile>. It is 
 also superior in point of tractive <|ualities, *'takin<r hold" of the 
 roadbed far nioie effectively than the best solid <ire. It has. how- 
 evei-. one notable disadvantage, the constant liability to iMincture, 
 with the conse(|uent danger of being rendered iiseh-s. In order to 
 remedy this defect, imentors and manufacturers ha\e inti'odnced 
 such features as thickening the tread of the tire, increasing its resist- 
 ance to |)uncture by inserting layers of tough fabi-ic in the rubber 
 walls, and reenforcing the tread siii-faci* in various ways. Pneumatic 
 tires are almost universally used on automobiles, the soliil type being 
 confined to electrics and trucks intended for city service. 
 
 Cuts, due to stones or other sharp obvstades. tend to spread to the 
 center of the tire, across the tread. This is due to the qnality of the 
 strains transmitted from the wheels, and in order lo i)re\ent the tie- 
 
150 TENTATIVE MANUAL OF INSTRUCTION. 
 
 struction of the tire, it is necessary to vary the shape. Accordingly^ 
 tires are made with beveled edges, rather than on square lines. This 
 conformation, together with a good Avidtli at the rim. is able to pro- 
 vide for absoi'bing much of the surplus vibration, vvhile decreasing 
 the ill eii'ects due to the combined action of a heavy load and road 
 resistance. The most valuable quality -of the pneumatic tire is its 
 resiliency, or ability to bounce in the act of regaining its usual form 
 after encountering an obstacle in the road. On encountering a stone^ 
 for example, it will yield to a certain extent, absorbing or " swallow- 
 ing it up,"' at the same time exerting a pressure sufficient to restore 
 its normal shape. I'he latter quality has two advantages for easy 
 riding: (1) It does away Avith much of the lifting up of the wheel 
 in passing over obstacles, which is otherwise inevitable, and (2) it 
 enables the tire to obtain a better grip on the roadbed. 
 
 A pneumatic tire consists of an inner tube, which contains the 
 compressed air, and an outer casing or shoe ; the shoe is open along 
 its inner circumference, has projections or flanges which fit snugly 
 into channels formed l)y inturning the edges of the rim to hold the 
 tire in place. These channels are the " clinches," hence the name 
 "clincher tir(\'" Sometimes the inner tube is protected by a "flap." 
 In removing tlie shoe, it is necessary to insert a flat tool between it 
 and the rim and pry them apart. This operation is tedious, and also 
 involves severe strain on the fabric. A careless hand may also cut 
 or bruise the inner tube, paiticularlv when it is not protected by a 
 flap. 
 
 Tires should be kept in cases, such as are provided for the purpose 
 by tire dealers. This rule applies with particular force to the very 
 elastic inner tubes, whicli should be stored in bags in some convenient 
 place away from the light and heat of the sun. Tires in use are not 
 as liable to injury from sunlight as the extra stored tires, for the 
 reason that the dust and mud of travel, while not directly contribut- 
 ing to the advantage of the rubber, seem to neutralize the ill effects 
 of the sun's rays. This is the best explanation of the fact that used 
 tires are less liable to injury than new ones. Some forms of wear 
 and tear of pneumatic tires are (1) puncture, (2) rim cutting, (3) 
 cracking of the walls, (4) excessive wear on the walls or tread, and 
 (5) chemical action. 
 
 The causes of rim cutting are : 
 
 (1) Sand or sharp particles lodged between the tire and the edges 
 of the rim, which, particularly when the tire is partially deflated, 
 cut through the outer layer of rubber to the fabric beneath. 
 
 (2) Overloading. This causes the tire to flatten, in spite of per- 
 sistent extra inflation, and the result is nearly always shearing off 
 at the edges near the points where the flanges engage the clinches. 
 
 (3) Defective or bent rims. Rims may be unsuited for given 
 makes of tires because made for some other style. It is essential 
 that the tire fit the rim perfectly, since if the attachment be not 
 tight, movement and chafing result, or stones and sand find lodg- 
 ment; if it be too tight, the pressure against the edges of the rim 
 is excessive. Loose or ill-fitting studs always allow some movement 
 of the tire, which usually results in cutting, at least in spots around 
 the rim. These mishaps occur less frcquentl}^ than those due to 
 bent or I'usty rims, Avhich woi'k the same havoc as those that fit 
 
ELEMENTARY AUTOMOTIVE ENGINEERING LECTURES. 151 
 
 poorly. It is necessary to keep the rim in repair and to clean ont 
 all the evidences of rust. 
 
 (4) Insufficient inllation. This is often a caii-e ol' cutting;, e\ erk 
 when the rims are in <ioo(l condition. It is necessary to keep tho 
 tires pumped hard at all times. If cuttin<2: then results, it is evident 
 that the tires are too small for the load they are oi)lifre(l to earry. 
 
 (5) Sharp curves or excessive "side step.*' Both tend to pi'<Mhue 
 a })ressure that is concentrated at the lim. and. in [)roportion to the 
 weif^ht of the car. or the speed at which it is driven, are liable to re- 
 sult in cuttinjiT of the shoi". Side slipijin*"- or skidding' is laifrely 
 neutralized in cars with long wheel base, hut. even with tliis desiral)le 
 structural feature, occasions may arise in which rim cnttin<r results 
 from sudden turns. 
 
 If a tire be well made, any evidence of cracking: cd' the shoe mat 
 safely be attributed to driving with insuflicient inllation. As a re- 
 sult of a puncture or other mishap, all the air may be exhausted, 
 causing the tire to be completely llatlened under the weight of the 
 vehicle. This is liable to cause cracking. Long-continued pressure 
 of this kind tears and destroys the fabric of the tire. It is imj^ortant 
 to keep the tire inflated to tlie proper pressuie. To neglect this will 
 cau.se the rapid deterioration of the tire. Kinming a tire Hal. even a 
 short distance, will ])rove exj^ensive. 
 
 The brake should not be applied suddenly unless absolutely neces- 
 sa ry . 
 
 When one side of a tire shows more wear than an<»tlicr. it shoidd 
 i>e turned around, .so as to reverse the sides. 
 
 High speed is very destructive to tires. 
 
 Grease and oils .should be carefully kept away from tires; they 
 attack the rubber. 
 
 Rims should be kept in good order, straight and true. Rust is 
 destructive. Paint preserves. 
 
 The weight of the cars should not lest on deilated tiies, not even 
 over night. 
 
 It is better to run on the rim. very slowly and carcd'ully. if neces- 
 sary and the distance be short, than on a flat tire. 
 
 Rear tires wear the more rapidly. Front and rear tires can there- 
 fore, be transposed sometimes to advantage. 
 
 The throttle should be used more, and the brakes less, in controllinir 
 the car. This saves both the tires and the machine. 
 
ELEMENTARY AUTOMOTIVE ENGINEERING. 
 
 LECTUKK XI. 
 MOTORCYCLES. 
 
 lusi ruction ili.uis Xos. 7, •_'•_', 118. 40, 41, and 42. K(iiiiiiiuem : Indian or Harley- 
 I'avidson motor cycle.) 
 
 Accoi'diiiii- to experience in the luattiT. a motorcycle must be pro- 
 pelled by an engine of somewhat higher power rating than is actuall}^ 
 required for tlie load to be carried. The reasons for both conditions 
 are apparent, since, having dispensed with the water cooling and 
 circulating system for sake ot" lightness and compactness, it is desir- 
 able to a\oid overheating which woidd occur at high engine speeds, 
 and such low ])ower as would cause the engine to labor under ordi- 
 nary loads. Mtjtorcycle.s, although much cheaper than automobiles, 
 are capable of the same speed as the average car: inoreover, the ex- 
 pense of fuel and upkeep is very small. 
 
 Engines of from two to seven horsepower are usually Htted to 
 motorcycles. About four horsej)ower is suitable for ordinary use. 
 The frauie and wheels are both made heaviei* and stronger than in 
 foot-pro]xdled machines. The tube^ are made with thicker walls, 
 and the joints more secmvly reinforced. Tn several makes the end 
 of security is further assui-ed by struts and trusses, particidarly at 
 the fork on the steering post and at the })lace where the engine is 
 hung. 
 
 A one-cylinder four-cycle engine is in counnon u.se, although two 
 and four cylinder engines are used on (he higher powei-ed machines. 
 The "A'"' twin-cylinder engine is generally used: it is popular on 
 ai'count of its simplicity and lightnes'-. there being only one crank 
 an<l cam shaft for the two cylinders. It is located in a very low 
 position, so as to keep the center of gravity low, and make the ma- 
 chine easy to balance. With this location, the rider does not have 
 to straddle a hot engine, and the air strikes directly on the cylinder 
 liead. There has been a wide di\ersity in design in the location and 
 mode of attacliing the engine to the frame. Tn some makes it has 
 been supported on th(> backstays, between the pedal bearing and the 
 rear wheel; in one make on an extension of the backstays to rear 
 of the wheel: in several makes it is supported against or forms a 
 ])art of the rear or saddle tube member of the "diamond" frame. 
 The favorite position at the present time is on the forward part of 
 the franu', in front of the pedal bearing or on a tube arranged be- 
 neath, and suitably tru-.-ed to hold the weight. 
 
154 TENTATIVE MAX TAL OF IXSTRVCTION. 
 
 Motorcycles are ahvays air cooled. The engine is lubricated by the 
 splash system : oil is placed in the crank case and the motion of the 
 fly Avheel and connecting-rod end splashes it on the bearings, piston, 
 and cylinder walls. The A'alves are generally offset on one side of 
 the cylinder, being arranged one above the other. It is usual to tit 
 the exhaust valve with a lifter to hold the valve oft' its seat and thus 
 relieve compression in starting. This is operated by a conveniently 
 located lever. A spiral spring effects the return of the lever to its 
 original position. 
 
 Both inlet and exhaust valves are placed in the same pocket. The 
 inlet valve of the twin cylinder is operated by a lift rod, worked by 
 the cam. and :i rocking \v\ev that is mounted on the dome of the 
 valve chamber, and an adjusting screw is ])rovided in the end of 
 this rocking lever to regulate the amount of the opening in the valve. 
 The valve chamber dome is secured in position b}^ a bayonet joint,, 
 and may be removed, after disconnecting the induction pipe, by giv- 
 ing it a quarter turn. The inlet valve, with its seat, spring, etc... 
 conies out with the dome, from whicli they are withdrawn by the- 
 fingers. The removal of the doine exj^oses the exhaust valve for in- 
 spection. The high tension or jump-spark ignition is generally used. 
 A magneto is used for ignition and woiks on the same principle as on 
 a motor vehicle, except that instead of having four contact points it 
 has only two (one for each plug). 
 
 Some spring arrangement is included in the saddle post. In ad- 
 dition, a spring fork for the front wheel is usually provided for ab- 
 sorbing the jar. The speed of the machine is usually regulated by 
 adjusting or throttling the mixture and varying the time of the 
 spark, also by cutting out the ignition so as to miss explosions. With 
 some types of engine, the timing of the valves and spark is fixed so- 
 that unless \Nrongly assembled at the factory there is no chance of 
 trouble excepting, of course, in the event of the rare, but possible,, 
 breakage of a gear tooth. 
 
 There are three kinds of drive used on motorcycles — the belt, 
 the chain, and the shaft drive. The objections to the belt drive are 
 that it requires adjustment, and must be kept in tight contact to 
 })revent slippage of the small driving pulley on the engine: slippage 
 results in loss of power. A belt deteriorates rapidly, due to moisfure,. 
 dirt, etc., hence, it requires freiiuent repairs and renewal. The use of 
 round, V-shaped and even flat belts, does not always give satisfaction. 
 The great tension to which belts have to be suV)jected in order to in- 
 sure proper adhesion, and still more, the alternate actions of dry and 
 wet weather, cause them to stretch. This drawback frequently 
 necessitates repairs on the road. Finally, the traction exercised by 
 the belt on one of the ends of the hub hinders the proper Avorking of 
 the latter. 
 
 The chain, and shaft drive furnish a positive connection between 
 the engine and rear wheel. The chain drive is furnished on a num- 
 ber of the medium-priced machines, and the shaft drive on the more 
 expensive machines. While the chain is a satisfactory and inex- 
 pensive drive, the shaft with its inclosed gears is entirely protected 
 from dust and does not present any lubricated surfaces to soil the 
 rider's clothing; 
 
 The transmission used on >ome motor cycles is provided with a three- 
 speed and free-engine transmission; others have in place of sliding" 
 
ELEMENTARY AVTOMOTIVE ENGINEERING LECTURES. 155 
 
 ^oais a form of friction clutch by which the power iiuiy be gradually 
 a]>plied in starting. The advantages gained l)y the use of a trans- 
 mission are that it enables the rider (1) to climl) steeper hills, (2) 
 malvcs it ]K)Ssiblp to stop and restart at will without dismounting, 
 cillicr on level load or on the steejx'st hill, l)v means of the free 
 ougiiie. (.")) to slow down or even come to a dead stop, if "pocketed" 
 in a congested sti-eet. and (4) restart witlioul ))edaling. 
 
 In operating a motor cycle before starting: (1) the various parts 
 of the machine should be carefully examined, (2) the gasoline tank 
 and lubricating devices tilled, (3) gasoline valve opened, (4) car- 
 buretor i)rimed and throttle opened, (.">) the exhaust valves raised, 
 (t>) ignition cut-out plug inserted, (7) handlel)ar ignition switch 
 open(>d, and (S) spark well advanced by means (»f the lever provided 
 lor the i)uri)ose. As soon as the engine begins lo operate, the spark 
 should i)e retai'ded and adjusted together with the (hrottle to meet 
 the speed re(|uiren)enls. On motor cycles, as a rule, the speed is 
 varied chielly by the spark ]iosition. The control of the machine, 
 at slow speeds, is made more flexible l)y the use of the handlebar 
 ignition switch. 
 
 Tn descending a hill: (1) the ignition should be cut out with the 
 handlebar switch. (2) throttle closed, and (>>) exhaust valves lifted: 
 the latter o|)eration relieves the drag of (he engine and admits fresh 
 ail" to the cylinders, which has a tendency to keej) the spark l)lug 
 points clean and clear the cylinder of carl)on deposits. In operating 
 a motor cycle, it is important that the lubrication of the engine 
 receive frequent attention — say every 10 miles. The crank case 
 should receive sufficient oil that it may splash up against the piston 
 and cylinder walls. Occasionally the crank case should be draiiUMJ. 
 washed oul Avith gasoline, and a fresh sni)ly of oil provided. AVhen 
 it is desired to stop: (1) tlie ignition should be cut out by the handle- 
 i)ar switch. (2) exhaust valve lifted, and (H) brakes applied, (iaso- 
 line is supj^lied l)y gravity, from a tank located o\er the motor, to 
 the carburetor which is located on the side of the engine midway be- 
 tween the cylinders. 
 
 Pneumatic tires are used on both front and rear wheels. Brakes 
 are of the contracting band type, and are o])erated either by a foot 
 l)edal or by hand. The clutch is operated by either the foot or hand. 
 
LABORATORY EXERCISE SPECIFICATIONS. 
 
 These are intended to afforil a basis (1) for eqiiii)nient nei'i'ssaiy 
 for a unit and (2) for student assignment. 
 
 Oil pumps (2) 
 
 Ciirlniretors (1 ) (sectionali'.r<l: ;isseinlil(.'(l) 
 
 < lilinK sysioins coinplctc ( 1 ) 
 
 • Jrtsolinc system complete (I) 
 
 Vacuum system complete (1 ) 
 
 < loveriiors (2) 
 
 Kinliators (1 ) 
 
 ^'ater pumg (i; 
 
 ( hassis complete 
 
 Storage batteries (1) 
 
 Storaj;e batteries (1) sectionalizecl ami disassembled. 
 Coils (2). 
 
 Uistributors (2) 
 
 Itiuitiou set c-omplete (1) 
 
 • ienerators (I assembled; I disassembled: 1 seetionalizcd) . 
 
 Cut -outs (2) 
 
 Magneto and plug ;issembly ( 1 ) 
 
 Switdi ami fuse blocks (2) 
 
 Starting motor clutch (I) : 
 
 Clutch asscmlily ( 1 ) :> 
 
 Propeller shaft assembly (1) 
 
 Hear axle assembly complete (1) 
 
 Front axle and steering mechanism ( 1 ) 
 
 Wheels and tires (5) 
 
 Brake assemblies (2) 
 
 StudcJits. 
 
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