LIBRARY 
 
 UNIVERSITY OF CALIFORNIA. 
 
 Class 
 
FLYING MACHINES: 
 
 CONSTRUCTION and OPERATION 
 
 A Practical Book Which Shows, in Illustra- 
 tions, Working Plans and Text, How 
 to Build and Navigate the 
 Modern Airship. 
 
 By 
 W. J. J if \CKMAN, M. E., 
 
 Author of " A B C >t of the Motorcycle," 
 "Facts for Motorists," etc., etc. 
 
 AND 
 
 THOS. H. RUSSELL, A. M., M. E. 
 
 Charter Member of the Aero Club of Illinois, Author of 
 "History of the Automobile." "Motor Boats: Construc- 
 tion and Operation," etc., etc. 
 
 WITH INTRODUCTORY CHAPTER BY 
 
 OCTAVE CHANUTE, C. E.. 
 
 President Aero Club of Illinois 
 
 1910 
 
 THE CHARLES C. THOMPSON CO. (Not Inc.) 
 CHICAGO, U. S. A. 
 

 Copyrighted 1910 
 
 By THE CHARLES C. THOMPSON CO. 
 (Not Inc.) 
 
 CHICAGO 
 
PREFACE. 
 
 This book is written for the guidance of the novice in 
 aviation the man who seeks practical information as to 
 the theory, construction and operation of the modern 
 flying machine. With this object in view the wording 
 is intentionally plain and non-technical. It contains some 
 propositions which, so far as satisfying the experts is 
 concerned, might doubtless be better stated in technical 
 terms, but this would defeat the main purpose of its pre- 
 paration. Consequently, while fully aware of its short- 
 comings in this respect, the authors have no apologies to 
 make. 
 
 In the stating of a technical proposition so it may be 
 clearly understood by people not versed in technical mat- 
 ters it becomes absolutely necessary to use language 
 much different from that which an expert would employ, 
 and this has been done in this volume. 
 
 No man of ordinary intelligence can read this book 
 without obtaining a clear, comprehensive knowledge of 
 flying machine construction and operation. He will 
 learn, not only how to build, equip, and manipulate an 
 aeroplane in actual flight, but will also gain a thorough 
 understanding of the principle upon which the suspension 
 in the air of an object much heavier than the air is made 
 possible. 
 
 This latter feature should make the book of interest 
 even to those who have no intention of constructing or 
 operating a flying machine. It will enable them to bet- 
 
 203806 
 
4 ' FLYING MACHINES: 
 
 ter understand and appreciate the performances of the 
 daring men like the Wright brothers; Curtiss, Bleriot, 
 Farman, Paulhan, Latham, and others, whose bold ex- 
 periments have made aviation an actuality. 
 
 For those who wish to engage in the fascinating pas- 
 time of construction and operation it is intended as a 
 reliable, practical guide. 
 
 It may be well to explain that the sub-headings in the 
 articles by Mr. Chanute were inserted by the authors 
 without his knowledge. The purpose of this was merely 
 to preserve uniformity in the typography of the book. 
 This explanation is made in justice to Mr. Chanute. 
 
 THE AUTHORS. 
 
 The authors desire to make acknowledgment of many courtesies 
 in the way of valuable advice, information, etc., extended by Mr. 
 Octave Chanute, C. E., Mr. E. L. Jones, Editor of Aeronautics, and 
 the publishers of the New England Automobile Journal and Fly. 
 
CONTENTS 
 
 Chapter Page 
 
 I. Evolution of the Two-Surface Flying Machine 7 
 
 Introductory Chapter by Octave Chanute, C. E. 
 
 II. Theory, Development and Use 19 
 
 Origin of the Aeroplane Developments by Chanute 
 and the Wrights Practical Uses and Limits. 
 
 III. Mechanical Bird Action 23 
 
 What the Motor Does Puzzle in Bird Soaring. 
 
 IV. Various Forms of Flying Machines 29 
 
 Helicopters, Ornithopters and Aeroplanes Mono- 
 planes, Biplanes and Triplanes. 
 
 V. Constructing a Gliding Machine 33 
 
 Plans and Materials Required Estimate of Cost 
 Sizes and Preparation of Various Parts Putting the 
 Parts Together. 
 
 VI. Learning to Fly 47 
 
 How to Use the Glider Effect of Body Movements 
 Rules for Beginners Safest Place to Glide. 
 
 VII. Putting On the Rudder 57 
 
 Its Construction, Application and Use. 
 
 VIII. The Real Flying Machine 61 
 
 Surface Area Required Proper Size of Frame and 
 Auxiliaries Installation of Motor Cost of Con- 
 structing Machine. 
 
 IX. Selection of the Motor 83 
 
 Essential Features Multiplicity of Cylinders Power 
 Required Kind and Action of Propellers Placing 
 of the Motor. 
 
 X. Proner Dimensions of Machines 101 
 
 Figuring Out the Details How to Estimate Load 
 Capacity Distribution of the Weight Measurements 
 of Leading Machines. 
 
CONTENTS 
 
 Chapter Page 
 XL Plane and Rudder Control 109 
 
 Various Methods In Use Wheels and Hand and 
 
 Foot Levers. 
 
 XII. How to Use the Machine 115 
 
 Rules of Leading Aviators Rising From the Ground 
 Reasonable Altitude Preserving Equilibrium 
 Learning to Steer. 
 
 XIII. Peculiarities of Aeroplane Power 123 
 
 Pressure of the Wind How to Determine Upon 
 Power Why Speed Is Required Bird and Flying 
 Machine Areas. 
 
 XIV. About Wind Currents, Etc 133 
 
 Uncertainty of Direct Force Trouble With Gusty 
 Currents Why Bird Action Is Imitated. 
 
 XV. The Element of Danger 141 
 
 Risk Small Under Proper Conditions Two Fields 
 of Safety Lessons in Recent Accidents. 
 
 XVI. Radical Changes Being Made 145 
 
 Results of Recent Experiments New Dimensions 
 Increased Speed The One Governing Rule. 
 
 XVII. Some of the New Designs 155 
 
 Automatic Control of Plane Stability Inventor Her- 
 ring's Devices Novel Ideas of Students. 
 
 XVIII. Demand for Flying Machines 163 
 
 Wonderful Results in a Year Factories Overcrowded 
 with Orders. 
 
 XIX. Law of the Airship 169 
 
 Rights of Property Owners Some Legal Pecu- 
 liarities Danger of Trespass. 
 
 XX. Soaring Flight 179 
 
 What We Can Learn From Birds. 
 
 XXI. Flying Machines vs. Balloons 191 
 
 Advantages and Disadvantages of Each. 
 
 XXII. Problems of Aerial Flight IQ7 
 
 XXIII. Amateurs May Use Wright Patents 205 
 
 XXIV. Hints on Propeller Construction 213 
 
 XXV. Glossary of Aeronautical Terms 219 
 
EVOLUTION OF TWO-SURFACE FLYING 
 MACHINE. 
 
 By Octave Chanute. 
 
 I am asked to set forth the development of the "two- 
 surface" type of flying machine which is now used with 
 modifications by Wright Brothers, Farman, *Delagrange, 
 Herring and others. 
 
 This type originated with Mr. F. H. Wenham, who 
 
 Gliding Machine Used by Pilcher. 
 
 patented it in England in 1866 (No. 1571), taking out 
 provisional papers only. In the abridgment of British 
 patent Aeronautical Specifications (1893) it is described 
 as follows : 
 
 "Two or more aeroplanes are arranged one above the 
 other, and support a framework or car containing the 
 motive power: The aeroplanes are made of silk or can- 
 vas stretched on a frame by wooden rods or steel ribs. 
 When manual power is employed the body is placed 
 horizontally, and oars or propellers are actuated by the 
 arms or legs. 
 
 *Now dead. 
 
8 FLYING MACHINES: 
 
 "A start may be obtained by lowering the legs and 
 running down hill, or the machine may be started from 
 a moving carriage. One or more screw propellers may 
 be applied for pro'pelling when steam power is em- 
 ployed." 
 
 On June 27, 1866, Mr. Wenham read before the "Aero- 
 nautical Society of Great Britain," then recently organ- 
 ized, the ablest paper ever presented to that society, and 
 thereby breathed into it a spirit which has continued to 
 this day. In this paper he described his observations of 
 birds, discussed the laws governing flight as to the sur- 
 faces and power required both with wings and screws, 
 and he then gave an account of his own experiments with 
 models and with aeroplanes of sufficient size to carry 
 the weight of a man. 
 
 Second Wenham Aeroplane. 
 
 His second aeroplane was sixteen feet from tip to tip. 
 A trussed spar at the bottom carried six superposed 
 bands of thin holland fabric fifteen inches wide, con- 
 nected with vertical webs of holland two feet apart, thus 
 virtually giving a length of wing of ninety-six feet and 
 one hundred and twenty square feet of supporting sur- 
 face. The man was placed horizontally on a base board 
 beneath the spar. This apparatus when tried in the wind 
 was found to be unmanageable by reason of the fluttering 
 motions of the fabric, which was insufficiently stiffened 
 with crinoline steel, but Mr. Wenham pointed out that 
 this in no way invalidated the principle of the apparatus, 
 which was to obtain large supporting surfaces without 
 increasing unduly the leverage and consequent weight 
 of spar required, by simply superposing the surfaces. 
 
 This principle is entirely sound and it is surprising that 
 it is, to this day, not realized by those aviators who are 
 hankering for monoplanes. 
 
CONSTRUCTION AND OPERATION 9 
 
 Experiments by Stringfellow. 
 
 The next man to test an apparatus with superposed 
 surfaces was Mr. Stringfellow, who, becoming 1 much im- 
 pressed with Mr. Wenham's proposal, produced a largish 
 model at the exhibition of the Aeronautical Society in 
 1868. It consisted of three superposed surfaces aggre- 
 
 One of the First Hargrave Kites. 
 
 gating 28 square feet and a tail of 8 square feet more. 
 The weight was under 12 pounds and it was driven by a 
 central propeller actuated by a steam engine overesti- 
 mated at one-third of a horsepower. It ran suspended 
 to a wire on its trials but failed of free flight, in conse- 
 quence of defective equilibrium. This apparatus has 
 since been rebuilt and is now in the National Museum 
 of the Smithsonian Institution at Washington, 
 
10 FLYING MACHINES: 
 
 Linfield's Unsuccessful Efforts. 
 
 In 1878 Mr. Linfield tested an apparatus in England 
 consisting of a cigar-shaped car, to which was attached 
 on each side frames five feet square, containing each 
 twenty-five superposed planes of stretched and varnished 
 linen eighteen inches wide, and only two inches apart, 
 thus reminding one of a Spanish donkey with panniers. 
 The whole weighed two hundred and forty pounds. This 
 was tested by being mounted on a flat car behind a loco- 
 motive going 40 miles an hour. When towed by a line 
 fifteen feet long the apparatus rose only a little from the 
 car and exhibited such unstable equilibrium that the ex- 
 periment was not renewed. The lift was only about one- 
 third of what it would have been had the planes been 
 properly spaced, say their full width apart, instead of 
 one-ninth as erroneously devised. 
 
 Renard's "Dirigible Parachute." 
 
 In 1889 Commandant Renard, the eminent superin- 
 tendent of the French Aeronautical Department, exhib- 
 ited at the Paris Exposition of that year, an apparatus 
 experimented with some years before, which he termed 
 a "dirigible parachute." It consisted of an oviform body 
 to which were pivoted two upright slats carrying above 
 the body nine long superposed flat blades spaced about 
 one-third of their width apart. When this apparatus 
 was properly set at an angle to the longitudinal axis of 
 the body and dropped from a balloon, it travelled back 
 against the wind for a- considerable distance before 
 alighting. The course could be varied by a rudder. *No 
 practical application seems to have been made of this 
 device by the French War Department, but Mr. J. P. 
 Holland, the inventor of the submarine boat whict bears 
 his name, proposed in 1893 an arrangement of pivoted 
 
CONSTRUCTION AND OPERATION 
 
 11 
 
 framework attached to the body of a flying machine 
 which combines the principle of Commandant Renard 
 with the curved blades experimented with by Mr. Phil- 
 lips, now to be noticed, with the addition of lifting screws 
 inserted among the blades. 
 
 Phillips Fails on Stability Problem. 
 
 In 1893 Mr. Horatio Phillips, of England, after some 
 very interesting experiments with various wing sections, 
 from which he deduced conclusions as to the shape of 
 
 Hargrave Kite With Vibrating Wings. 
 
 maximum lift, tested an apparatus resembling a Vene- 
 tian blind which consisted of fifty wooden slats of 
 peculiar shape, 22 feet long, one and a half inches wide, 
 and two inches apart, set in ten vertical upright boards. 
 All this was carried upon a body provided with three 
 wheels. It weighed 420 pounds and was driven at 40 
 miles an hour on a wooden sidewalk by a steam engine 
 of nine horsepower which actuated a two-bladed screw. 
 The lift was satisfactory, being perhaps 70 pounds per 
 horsepower, but the equilibrium was quite bad and the 
 experiments were discontinued. They were taken up 
 again in 1904 with a similar apparatus large enough to 
 carry a passenger, but the longitudinal equilibrium was 
 found to be defective. Then in 1907 a new machine was 
 
12 FLYING MACHINES: 
 
 tested, in which four sets of frames, carrying similar sets 
 of slat "sustainers" were inserted, and with this arrange- 
 ment the longitudinal stability was found to be very sat- 
 isfactory. The whole apparatus, with the operator, 
 weighed 650 pounds. It flew about 200 yards when 
 driven by a motor of 20 to 22 h.p. at 30 miles an hour, 
 thus exhibiting a lift of about 32 pounds per h.p., while 
 it will be remembered that the aeroplane of Wright 
 Brothers exhibits a lifting capacity of 50 pounds to 
 the h.p. 
 
 Hargrave's Kite Experiments. 
 
 After experimenting with very many models and 
 building no less than eighteen monoplane flying model 
 machines, actuated by rubber, by compressed air and by 
 steam, Mr. Lawrence Hargrave, of Sydney, New South 
 Wales, invented the cellular kite which bears his name 
 and made it known in a paper contributed to the Chi- 
 cago Conference on Aerial Navigation in 1893, describ- 
 ing several varieties. The modern construction is well 
 known, arid consists of two cells, each of superposed sur- 
 faces with vertical side fins, placed one behind the other 
 and connected by a rod or frame. This flies with great 
 steadiness without a tail. Mr. Hargrave's idea w r as to 
 use a team of these kites, below which he proposed to 
 suspend a motor and propeller from which a line would 
 be carried to an anchor in the ground. Then by actu- 
 ating the propeller the whole apparatus would move 
 forward, pick up the anchor and fly away. He said: 
 "The next step is clear enough, namely, that a flying 
 machine with acres of surface can be safely got under 
 way or anchored and hauled to the ground by means of 
 the string of kites." 
 
 The first tentative experiments did not result well and 
 emphasized the necessity for a light motor, so that Mr. 
 Hargrave has since been engaged in developing one, not 
 
CONSTRUCTION AND OPERATION 
 
 13 
 
 having convenient access to those which have been pro- 
 duced by the automobile designers and builders. 
 
 Experiments With Glider Model. 
 
 And here a curious reminiscence may be indulged in. 
 In 1888 the present writer experimented with a two-cell 
 
 Glider of Lilienthal Type. 
 
 gliding model, precisely similar to a Hargrave kite, as 
 will be confirmed by Mr. Herring. It was frequently 
 tested by launching from the top of a three-story house 
 and glided downward very steadily in all sorts of breezes, 
 but the angle of descent was much steeper than that of 
 birds, and the weight sustained per square foot was less 
 than with single cells, in consequence of the lesser sup- 
 port afforded by the rear cell, which operated upon air 
 
14 FLYING MACHINES: 
 
 already set in motion downward by the front cell, so 
 nothing more was done with it, for it never occurred to 
 the writer to try it as a kite and he thus missed the dis- 
 tinction which attaches to Hargrave's name. 
 
 Sir Hiram Maxim also introduced fore and aft super- 
 posed surfaces in his wondrous flying machine of 1893, 
 but he relied chiefly for the lift upon his main large sur- 
 face and this necessitated so many guys, to prevent dis- 
 tortion, as greatly to increase the head resistance and 
 this, together with the unstable equilibrium, made it 
 evident that the design of the machine would have to 
 be changed. 
 
 How Lilienthal Was Killed. 
 
 In 1895, Otto Lilienthal, the father of modern aviation, 
 the man to whose method of experimenting almost all 
 present successes are due, after making something like 
 two thousand glides with monoplanes, added a super- 
 posed surface to his apparatus and found the control of 
 it much improved. The two surfaces were kept apart 
 by two struts or vertical posts with a few guy wires, but 
 the connecting joints were weak and there was nothing 
 like trussing. This eventually cost his most useful life. 
 Two weeks before that distressing loss to science, Herr 
 Wilhelm Kress, the distinguished and veteran aviator 
 of Vienna, witnessed a number of glides by Lilienthal 
 with his double-decked apparatus. He noticed that it 
 was much wracked and wobbly and wrote to me after 
 the accident : "The connection of the wings and the 
 steering arrangement were very bad and unreliable. I 
 warned Herr Lilienthal very seriously. He promised 
 me that he would soon put it in order, but I fear that he 
 did not attend to it immediately." 
 
 In point of fact, Lilienthal had built a new machine, 
 upon a different principle, from which he expected great 
 results, and intended to make but very few more flights 
 
CONSTRUCTION AND OPERATION 15 
 
 with the old apparatus. He unwisely made one too 
 many and, like Pilcher, was the victim of a distorted 
 apparatus. Probably one of the joints of the struts 
 gave way, the upper surface blew back and Lilienthal, 
 who was well forward on the lower surface, was pitched 
 headlong to destruction. 
 
 Experiments by the Writer. 
 
 In 1896, assisted by Mr. Herring and Mr. Avery, I 
 experimented with several full sized gliding machines, 
 
 Prof. Langley's Aerodrome. 
 
 carrying a man. The first was a Lilienthal monoplane, 
 which was deemed so cranky that it was discarded after 
 making about one hundred glides, six weeks before 
 Lilienthal's accident. The second was known as the 
 multiple winged machine and finally developed into five 
 pairs of pivoted wings, trussed together at the front and 
 
16 FLYING MACHINES: 
 
 one pair in the rear. It glided at angles of descent of 
 10 or ii degrees or of one in five, and this was deemed 
 too steep. Then Mr. Herring and myself made compu- 
 tations to analyze the resistances. We attributed much 
 of them to the five front spars of the wings and on a 
 sheet of cross-barred paper I at once drew the design for 
 a new three-decked machine to be built by Mr. Herring. 
 Being a builder of bridges, I trussed these surfaces 
 together, in order to obtain strength and stiffness. When 
 tested in gliding flight the lower surface \vas found too 
 near the ground. It was taken off and the remaining 
 apparatus now consisted of two surfaces connected to- 
 gether by a girder composed of vertical posts and diag- 
 onal ties, specifically known as a "Pratt truss.'' Then 
 Mr. Herring and Mr. Avery together devised and put 
 on an elastic attachment to the tail. This .machine 
 proved a success, it being safe and manageable. Over 
 700 glides w r ere made with it at angles of descent of 8 
 to 10 degrees, or one in six to one in seven. 
 
 First Proposed by Wenham. 
 
 The elastic tail attachment and the trussing of the 
 connecting frame of the superposed wings were the only 
 novelties in this machine, for the superposing of the 
 surfaces had first been proposed by Wenham, but in 
 accordance with the popular perception, which bestows 
 all the credit upon the man who adds the last touch 
 making for success to the labors of his predecessors, the 
 machine has since been known by many persons as the 
 "Chanute type" of gliders, much to my personal grati- 
 fication. 
 
 It has since been improved in many ways. Wright 
 Brothers, disregarding the fashion which prevails among 
 birds, have placed the tail in front of their apparatus and 
 called it a front rudder, besides placing the operator in 
 
CONSTRUCTION AND OPERATION 17 
 
 horizontal position instead of upright, as I did; and also 
 providing a method of warping the wings to preserve 
 equilibrium. Farman and Delagrange, under the very 
 able guidance and constructive work of Voisin brothers, 
 then substituted many details, including a box tail for 
 the dart-like tail which 1 used. This may have increased 
 the resistance, but it adds to the steadiness. Now the 
 
 
 Chanute's Multiplane Glider. 
 
 tendency in France seems to be to go back to the mono- 
 plane. 
 
 Monoplane Idea Wrong. 
 
 The advocates of the single supporting surface are 
 probably mistaken. It is true that a single surface 
 shows a greater lift per square foot than superposed 
 surfaces for a given speed, but the increased weight due 
 to leverage more than counterbalances this advantage by 
 requiring heavy spars and some guys. I believe that 
 the future aeroplane dynamic flier will consist of super- 
 posed surfaces, and, now that it has been found that by 
 
18 FLYING MACHINES: 
 
 imbedding suitably shaped spars in the cloth the head 
 resistance may be much diminished, I see few objections 
 to superposing three, four or even five surfaces properly 
 trussed, and thus obtaining a compact, handy, manage- 
 able and comparatively light apparatus.* 
 
 *Aeronautics. 
 
CHAPTER II. 
 
 THEORY, DEVELOPMENT, AND USE. 
 
 While every craft that navigates the air is an air- 
 ship, all airships are not flying machines. The balloon, 
 for instance, is an airship, but it is not what is known 
 among aviators as a flying machine. This latter term 
 is properly used only in referring to heavier-than-air 
 machines which have no gas-bag lifting devices, and are 
 
 Imitation of Bird In Aeroplane Design. 
 
 made to really fly by the application of engine propul- 
 sion. 
 
 Are Mechanical Birds. 
 
 All successful flying machines and there are a num- 
 ber of them are based on bird action. The various 
 designers have studied bird flight and soaring, mastered 
 its technique as devised by Nature, and the modern fly- 
 ing machine is the result. On an exaggerated, enlarged 
 scale, the machines which are now navigating the air 
 are nothing more nor less than mechanical birds. 
 
 19 
 
20 FLYING MACHINES: 
 
 Origin of the Aeroplane. 
 
 Octave Chanttte, of Chicago, may well be called "the 
 developer of the flying machine." Leaving balloons and 
 various forms of gas-bags out of consideration, other 
 experimenters, notably Langley and Lilienthal, ante- 
 dated him in attempting the navigation of the air on 
 aeroplanes, or flying machines, but none of them were 
 wholly successful, and it remained for Chanute to dem- 
 onstrate the practicability of what was then called the 
 gliding machine. This term was adopted because the 
 apparatus was, as the name implies, simply a gliding 
 machine, being without motor propulsion, and intended 
 solely to solve the problem of the best form of con- 
 struction. The biplane, used by Chanute in 1896, is 
 still the basis of most successful flying machines, the 
 only radical difference being that motors, rudders, etc., 
 have been added. 
 
 , Character of Chanute's Experiments. 
 
 It was the privilege of the author of this book to be 
 Mr. Chanute's guest at Millers, Indiana, in 1896, when, 
 in collaboration with Messrs. Herring and Av.ery, he was 
 conducting the series of experiments which have since 
 made possible the construction of the modern flying 
 machine which such successful aviators as the Wright 
 brothers and others are now using. It was a wild 
 country, much frequented by eagles, hawks, and similar 
 birds. The enthusiastic trio, Chanute, Herring and 
 Avery, would watch for hours the evolutions of some 
 big bird in the air, agreeing in the end on the verdict, 
 "When we master the principle of that bird's soaring 
 without wing action, we will have come close to solving 
 the problem of the flying machine." 
 
 Aeroplanes of various forms were constructed by Mr. 
 
CONSTRUCTION AND OPERATION 21 
 
 Chanute with the assistance of Messrs. Herring and 
 Avery until, at the time of the writer's visit, they had 
 settled upon the biplane, or two-surface machine. Mr. 
 Herring later equipped this with a rudder, and made 
 other additions, but the general idea is still the basis of 
 the Wright, Curtiss, and other machines in which, by 
 the aid of gasolene motors, long flights have been made. 
 
 Developments by the Wrights. 
 In 1900 the Wright brothers, William and Orville, 
 
 Chanute Glider Equipped With Rudder. 
 
 who were then in the bicycle business in Dayton, Ohio, 
 became interested in Chanute's experiments and com- 
 municated with him. The result was that the Wrights 
 took up Chanute's ideas and developed them further, 
 making many additions of their own, one of which was 
 the placing of a rudder in front, and the location of the 
 
22 FLYING MACHINES: 
 
 operator horizontally on the machine, thus diminishing 
 by four-fifths the wind resistance of the man's body. 
 For three years the Wrights experimented with the 
 glider before venturing to add a motor, which was not 
 done until they had thoroughly mastered the control of 
 their movements in the air. 
 
 Limits of the Flying Machine. 
 
 In the opinion of competent experts it is idle to look 
 for a commercial future for the flying machine. There 
 is, and always will be, a limit to its carrying capacity 
 which will prohibit its employment for passenger or 
 freight purposes in a wholesale or general way. There 
 are some, of course, who will argue that because a 
 machine will carry two people, another may be con- 
 structed that will carry a dozen, but those who make 
 this contention do not understand the theory of weight 
 sustentation in the air; or that the greater the load the 
 greater must be the lifting power (motors and plane 
 surface), and that there is a limit to these as will be 
 explained later on beyond which the aviator cannot go. 
 
 Some Practical Uses. 
 
 At the same time there are fields in which the flying 
 machine may be used to great advantage. These are: 
 
 Sports Flying machine races or flights will always 
 be popular by reason of the element of danger. It is 
 a strange, but nevertheless a true proposition, that it is 
 this element which adds zest to all sporting events. 
 
 Scientific For exploration of otherwise inaccessible 
 regions such as deserts, mountain tops, etc. 
 
 Reconnoitering In time of war flying machines may 
 be used to advantage to spy out an enemy's encamp- 
 ment, ascertain its defenses, etc. 
 
CHAPTER III. 
 
 MECHANICAL BIRD ACTION. 
 
 In order to understand the theory of the modern flying 
 machine one must also understand bird action and wind 
 action. In this connection the following simple expe- 
 riment will be of interest: 
 
 Take a circular-shaped bit of cardboard, like the lid of 
 a hat box, and remove the bent-over portion so as to 
 have a perfectly flat surface with a clean, sharp edge. 
 Holding the cardboard at arm's length, withdraw your 
 
 Illustrating the Effect of Motion on Sustentation. 
 23 
 
24 
 
 FL Y1NG MA CHINES : 
 
 hand, leaving the cardboard without support. What is 
 the result? The cardboard, being heavier than air, and 
 having nothing to sustain it, will fall to the ground. 
 Pick it up and throw it, with considerable force, against 
 the wind edgewise. What happens? Instead of falling 
 to the ground, the cardboard sails along on the wind, 
 remaining afloat so long as it is in motion. It seeks 
 the ground, by gravity, only as the motion ceases, and 
 then by easy stages, instead of dropping abruptly as in 
 the first instance. 
 
 Illustrating the Effect of Motion on Sustentation. 
 
 Here we have a homely, but accurate illustration of 
 the action of the flying machine. The motor does for 
 the latter what the force of your arm does for the card- 
 board imparts a motion which keeps it afloat. The 
 only real difference is that the motion given by the 
 motor is continuous and much more powerful than that 
 given by your arm. The action of the latter is limited 
 and the end of its propulsive force is reached within a 
 
CONSTRUCTION AND OPERATION 
 
 25 
 
 second or two after it is exerted, while the action of the 
 motor is prolonged. 
 
 Another Simple Illustration. 
 
 Another simple means of illustrating the principle of 
 flying machine operation, so far as sustentation and the 
 elevation and depression of the planes is concerned, is 
 explained in the accompanying diagram. 
 
 A is a piece of cardboard about 2 by 3 inches in size. 
 B is a piece of paper of the same size pasted to one edge 
 of A. If you bend the paper to a curve, with convex 
 side up and blow across it as shown in Figure C, the 
 paper will rise instead of being depressed: The dotted 
 lines show that the air is passing over the top of the 
 curved paper and yet, no matter how hard you may 
 
 F, D 
 
 Principle Upon Which Aeroplane Works. 
 
26 FLYING MACHINES: 
 
 blow, the effect will be to elevate the paper, despite the 
 fact that the air is passing over, instead of under the 
 curved surface. 
 
 In Figure D we have an opposite effect. Here the 
 paper is in a curve exactly the reverse of that shown in 
 Figure C, bringing the concave side up. Now if you 
 will again blow across the surface of the card the action 
 of the paper will be downward it will be impossible to 
 make it rise. The harder you blow the greater will be 
 the downward movement. 
 
 Principle In General Use. 
 
 This principle is taken advantage of in the construc- 
 tion of all successful flying machines. Makers of mono- 
 planes and biplanes alike adhere to curved bodies, with 
 the concave surface facing downward. Straight planes 
 were tried for a time, but found greatly lacking in the 
 power of sustentation. By curving the planes, and plac- 
 ing the concave surface downward, a sort of inverted bowl 
 is formed in which the air gathers and exerts a buoyant 
 effect. Just what the ratio of the curve should be is a 
 matter of contention. In some instances one inch to the 
 foot is found to be satisfactory; in others this is doubled, 
 and there are a few cases in which a curve of as much as 
 3 inches to the foot has been used. 
 
 Right here it might be well to explain that the word 
 "plane" applied to Hying machines of modern construc- 
 tion is in reality a misnomer. Plane indicates a flat, 
 level surface. As most successful flying machines have 
 curved supporting surfaces it is clearly wrong to speak 
 of "planes," or "aeroplanes." Usage, however, has made 
 the terms convenient and, as they are generally accepted 
 and understood by the public, they are used in like man- 
 in this volume. 
 
CONSTRUCTION AND OPERATION 
 
 27 
 
 Getting Under Headway. . 
 
 A bird, on first rising from the ground, or beginning 
 its flight from a tree, will flap its wings to get under 
 headway. Here again we have another illustration of 
 the manner in which a flying machine gets under head- 
 way the motor imparts the force necessary to put the 
 machine into the air, but right here the similarity ceases. 
 If the machine is to be kept afloat the motor must be 
 kept moving. A flying machine will not sustain itself ; 
 it will not remain suspended in the air unless it is 
 under headway. This is because it is heavier than air, 
 and gravity draws it to the ground. 
 
 How Machines Imitate Birds. 
 
 A bird and machine both on straight line; B bird and machine 
 ascending by elevation of head; C bird and machine descending 
 by depression of head. 
 
 Puzzle in Bird Soaring. 
 
 But a bird, which is also heavier than air, will remain 
 suspended, in a calm, will even soar and move in a 
 circle, without apparent movement of its wings. This 
 is explained on the theory that there are generally ver- 
 tical columns of air in circulation strong enough to sus- 
 tain a bird, but much too weak to exert any lifting power 
 on a flying machine. It is easy to understand how a 
 
28 FLYING MACHINES: 
 
 bird can remain suspended when the wind is in action, 
 but its suspension in a seeming dead calm was a puzzle 
 to scientists until Mr. Chanute advanced the proposition 
 of vertical columns of air. 
 
 Modeled Closely After Birds. 
 
 So far as possible, builders of flying machines have 
 taken what may be called "the architecture" of birds as 
 a model. This is readily noticeable in the form of con- 
 struction. When a bird is in motion its wings (except 
 when flapping) are extended in a straight line at right 
 angles to its body. This brings a sharp, thin edge 
 against the air, offering the least possible surface for 
 resistance, while at the same time a broad surface for 
 support is afforded by the flat, under side of the wings. 
 Identically the same thing is done in the construction of 
 the flying machine. 
 
 ' Note, for instance, the marked similarity in form as 
 shown in the illustration in Chapter II. Here A is the 
 bird, and B the general outline of the machine. The 
 thin edge of the plane in the latter is almost a duplicate 
 of that formed by the outstretched wings of the bird, 
 while the rudder plane in the rear serves the same pur- 
 pose as the bird's tail. 
 
CHAPTER IV. 
 
 VARIOUS FORMS OF FLYING MACHINES. 
 
 There are three distinct and radically different forms 
 of flying machines. These are : 
 
 Aeroplanes, helicopters and ornithopers. 
 
 Of these the aeroplane takes precedence and is used 
 almost exclusively by successful aviators, the helicopters 
 and ornithopers having been tried and found lacking in 
 some vital features, while at the same time in some 
 respects the helicopter has advantages not found in the 
 aeroplane. 
 
 What the Helicopter Is. 
 
 The helicopter gets its name from being fitted with 
 vertical propellers or helices (see illustration) by the 
 
 General Outline of Helicopter Machine. 
 
 action of which the machine is raised directly from the 
 ground into the air. This does away with the necessity 
 for getting the machine under a gliding headway before 
 
 29 
 
30 FLYING MACHINES: 
 
 it floats, as is the case with the aeroplane, and conse- 
 quently the helicopter can be handled in a much smaller 
 space than is required for an aeroplane. This, in many 
 instances, is an important advantage, but it is the only 
 one the helicopter possesses, and is more than overcome 
 by its drawbacks. The most serious of these is that the 
 helicopter is deficient in sustaining capacity, and requires 
 too much motive power. 
 
 Form of the Ornithopter. 
 
 The ornithopter has hinged planes which work like 
 the wings of a bird. At first thought this would seem 
 to be the correct principle, and most of the early exper- 
 imenters conducted their operations on this line. It 
 
 Ader's Ornithopter Constructed in 1882. 
 
 is now generally understood, however, that the bird in 
 soaring is in reality an aeroplane, its extended wings 
 serving to sustain, as well as propel, the body. At any 
 rate the ornithoper has not been successful in aviation, 
 and has been interesting mainly as an ingenious toy. 
 Attempts to construct it on a scale that would permit 
 of its use by man in actual aerial flights have been far 
 from encouraging. 
 
 Three Kinds of Aeroplanes. 
 
 There -are three forms of aeroplanes, with all of which 
 more or less success has been attained. These are: 
 
CONSTRUCTION AND OPERATION 31 
 
 The monoplane, a one-surfaced plane, like that used 
 by Bleriot. 
 
 The biplane, a two-surfaced plane, now used by the 
 Wrights, Curtiss, Farman, and others. 
 
 The triplane, a three-surfaced plane. This form is 
 but little used, its only prominent advocate at present 
 being Elle Lavimer, a Danish experimenter, who has not 
 thus far accomplished much. 
 
 Whatever of real success has been accomplished in 
 
 A Modern Form of Monoplane. 
 
 aviation may be credited to the monoplane and biplane, 
 with the balance in favor of the latter. The monoplane 
 is the more simple in construction and, where weight- 
 sustaining capacity is not a prime requisite, may prob- 
 ably be found the most convenient. This opinion is 
 based on the fact that the smaller the surface of the 
 plane the less will be the resistance offered to the air, 
 and the greater will be the speed at which the machine 
 may be moved. On the other hand, the biplane has a 
 much greater plane surface (double that of a monoplane 
 
32 
 
 FLYING MACHINES: 
 
 of the same size) and consequently much greater weight- 
 carrying capacity. 
 
 Differences in Biplanes. 
 
 While all biplanes are of the same general construc- 
 tion so far as the main planes are concerned, each aviator 
 has his own ideas as to the "rigging." 
 
 Wright, for instance, places a double horizontal rud- 
 der in front, with a vertical rudder in the rear. There 
 are no partitions between the main planes, and the 
 bicycle wheels used on other forms are replaced by skids. 
 
 Biplane Used by Delagrange. 
 
 Voisin, on the contrary, divides the main planes with 
 vertical partitions to increase stability in turning; uses 
 a single-plane horizontal rudder in front, and a big box- 
 tail with vertical rudder at the rear; also the bicycle 
 wheels. 
 
 Curtiss attaches horizontal stabilizing surfaces to the 
 upper plane ; has a double horizontal rudder in front, 
 with a vertical rudder and horizontal stabilizing surfaces 
 in rear. Also the bicycle wheel alighting gear. 
 
CHAPTER V. 
 
 CONSTRUCTING A GLIDING MACHINE. 
 
 First decide upon the kind of a machine you want 
 monoplane, biplane, or triplane. For a novice the bi- 
 plane will, as a rule, be found the most satisfactory as 
 it is more compact and therefore the more easily handled. 
 This will be easily understood when we realize that the 
 surface of a flying 1 machine should be laid out in pro- 
 portion to the amount of weight it will have to sustain. 
 The generally accepted rule is that 152 square feet of 
 surface will sustain the weight of an average-sized man, 
 say 170 pounds. Now it follows that if these 152 square 
 feet of surface are used in one plane, as in the mono- 
 plane, the length and width of this plane must be greater 
 than if the same amount of surface is secured by using 
 two planes the biplane. This results in the biplane 
 being more compact and therefore more readily manip- 
 ulated than the monoplane, which is an important item 
 for a novice. 
 
 Glider the Basis of Success. 
 
 Flying machines without motors are called gliders. In 
 making a flying machine you first construct the glider. 
 If you use it in this form it remains a glider. If you 
 install a motor it becomes a flying machine. You must 
 have a good glider as the basis of a successful flying 
 machine. 
 
 It will be well for the novice, the man who has never 
 had any experience as an aviator, to begin with a glider 
 
 33 
 
34 FLYING MACHINES: 
 
 and master its construction and operation before he 
 essays the more pretentious task of handling a fully- 
 equipped flying machine. In fact, it is essential that he 
 should do so. 
 
 Plans for Handy Glider. 
 
 A glider with a spread (advancing edge) of 20 feet, and 
 a breadth or depth of 4 feet, will be about right to begin 
 with. Two planes of this size will give the 152 square 
 yards of surface necessary to sustain a man's weight. 
 Remember that in referring to flying machine measure- 
 ments "spread" takes the place of what would ordinarily 
 be called "length," and invariably applies to the long 
 or advancing edge of the machine which cuts into the air. 
 Thus, a glider is spoken of as being 20 feet spread, and 
 4 feet in depth. So far as mastering the control of the 
 machine is concerned, learning to balance one's self in 
 the air, guiding the machine in any desired direction by 
 changing the position of the body, etc., all this may be 
 learned just as readily, and perhaps more so, with a 20- 
 foot glider than with a larger apparatus. 
 
 Kind of Material Required. 
 
 There are three all-important features in flying ma- 
 chine construction, viz. : lightness, strength and extreme 
 rigidity. Spruce is s the wood generally used for glider 
 frames. Oak, ash and hickory are all stronger, but they 
 are also considerably heavier, and where the saving of 
 weight is essential, the difference is largely in favor of 
 spruce. This will be seen in the following table : 
 
 Wood 
 
 Hickory 
 
 Weight 
 per cubic ft. 
 in Ibs. 
 
 C-? 
 
 Tensile 
 Strength 
 Ibs. per sq. in. 
 
 12 OOO 
 
 Compressive 
 Strength 
 Ibs. per sq. in. 
 
 8,^OO 
 
 Oak 
 
 CQ 
 
 12 OOO 
 
 Q.OOO 
 
 Ash 
 
 ..^8 
 
 1 2. OOO 
 
 ;/*"" 
 
 6,000 
 
CONSTRUCTION AND OPERATION 
 
 35 
 
 Walnut , 38 
 
 Spruce 25 
 
 Pine 25 
 
 8,000 
 8,000 
 5,000 
 
 6,000 
 5,000 
 4,500 
 
 Considering the marked saving in weight spruce has 
 a greater percentage of tensile strength than any of the 
 other woods. It is also easier to find in long, straight- 
 grained pieces free from knots, and it is this kind only 
 that should be used in flying machine construction. 
 
 One Method of Wiring Frame. 
 
 You will next need some spools or hanks of No. 6 
 linen shoe thread, metal sockets, a supply of strong 
 piano wire, a quantity of closely-woven silk or cotton- 
 cloth, glue, turnbuckles, varnish, etc. 
 
 Names of the Various Parts. 
 
 The long strips, four in number, which form the front 
 and rear edges of the upper and lower frames, are called 
 the horizontal beams. These are each 20 feet in length. 
 These horizontal beams are connected by upright strips, 
 
36 FLYING MACHINES: 
 
 4 feet long, called stanchions. There are usually 12 of 
 these, six on the front edge, and six on the rear. They 
 serve to hold the upper plane away from the lower one. 
 Next comes the ribs. These are 4 feet in length (pro- 
 jecting for a foot over the rear beam), and while in- 
 tended principally as a support to the cloth covering of 
 the planes, also tend to hold the frame together in a 
 horizontal position just as the stanchions do in the ver- 
 tical. There are forty-one of these ribs, twenty-one on 
 the upper and twenty on the lower plane. Then come 
 the struts, the main pieces which join the horizontal 
 beams. All of these parts are shown in the illustra- 
 tions, reference to which will make the meaning of the 
 various names clear. 
 
 Quantity and Cost of Material. 
 
 For the horizontal beams four pieces of spruce, 20 feet 
 long, \y 2 inches wide and ^J i nc h thick are necessary. 
 These pieces must be straight-grain, and absolutely free 
 from knots. If it is impossible to obtain clear pieces 
 of this length, shorter ones may be spliced, but this is 
 not advised as it adds materially to the weight. The 
 twelve stanchions should be 4 feet long and j inch in 
 diameter and rounded in form so as to offer as little 
 resistance as possible to the wind. The struts, there 
 are twelve of them, are 3 feet long by i^x^ inch. For 
 a 2O-foot biplane about 20 yards of stout silk or un- 
 bleached muslin, of standard one yard width, will be 
 needed. The forty-one ribs are each 4 feet long, and 
 y 2 inch square. A roll of No. 12 piano wire, twenty-four 
 sockets, a package of small copper tacks, a pot of glue, 
 and similar accessories will be required. The entire 
 cost of this material should not exceed $20. The wood 
 and cloth will be the two largest items, and these should 
 not cost more than $10. This leaves $10 for the varnish, 
 
CONSTRUCTION AND OPERATION 37 
 
 wire, tacks, glue, and other incidentals. This estimate 
 is made for cost of materials only, it being taken for 
 granted that the experimenter will construct his own 
 glider. Should the services of a carpenter be required 
 the total cost will probably approximate $60 or $70. 
 
 Application of the Rudders. 
 
 The figures given also include the expense of rudders, 
 but the details of these have not been included as the 
 glider is really complete without them. Some of the best 
 flights the writer ever saw were made by Mr. A. M. 
 
 20 FEET 
 
 4fc2 FT 
 
 Hh FT 
 
 2 rr 
 
 Mfe FT 
 
 f '/I FT 
 
 a < 5 
 
 Framework of Glider With Struts in Place. 
 
 Framework of Glider With Ribs in Place. 
 
 Herring in a glider without a rudder, and yet there can 
 be no doubt that a rudder, properly proportioned and 
 placed, especially a rear rudder, is of great value to the 
 aviator as it keeps the machine with its head to the 
 wind, which is the only safe position for a novice. For 
 initial educational purposes, however, a rudder is not 
 
38 FLYING MACHINES: 
 
 essential as the glides will, or should, be made on level 
 ground, in moderate, steady wind currents, and at a 
 modest elevation. The addition of a rudder, therefore, 
 may well be left until the aviator has become reasonably 
 expert in the management of his machine. 
 
 Putting the Machine Together. 
 
 Having obtained the necessary material, the first move 
 is to have the rib pieces steamed and curved. This curve 
 may be slight, about 2 inches for the 4 feet. AYhile 
 this is being done the other parts should be carefully 
 rounded so the square edges will be taken off. This 
 may be done with sand paper. Next apply a coat of 
 shellac, and when dry rub it down thoroughly with fine 
 sand paper. When the ribs are curved treat them in 
 the same way. 
 
 Lay two of the long horizontal frame pieces on the 
 floor 3 feet apart. Between these place six of the strut 
 pieces. Put one at each end, and each 4^ feet put 
 another, leaving a 2-foot space in the center. This will 
 give you four struts 4 T /< feet apart, and two in the center 
 2 feet apart, as shown in the illustration. This makes 
 five rectangles. Be sure that the points of contact are 
 perfect, and that the struts are exactly at right angles 
 with the horizontal frames. This is a most important 
 feature because if your frame "skews" or twists you 
 cannot keep it straight in the air. Now glue the ends 
 of the struts to the frame pieces, using plenty of glue, 
 and nail on strips that will hold the frame in place while 
 the glue is drying. The next day lash the joints together 
 firmly with the shoe thread, winding it as you would to 
 mend a broken gun stock, and over each layer put a 
 coating of glue. This done, the other frame pieces and 
 struts may be treated in the same way, and you will thus 
 get the foundations for the two planes. 
 
CONSTRUCTION AND OPERATION 39 
 
 Another Way of Placing Struts. 
 
 In the machines built for professional use a stronger 
 and more certain form of construction is desired. This 
 is secured by the placing the struts for the lower plane 
 under the frame piece, and those for the upper plane 
 over it, allowing them in each instance to come out flush 
 with the outer edges of the frame pieces. They are then 
 securely fastened with a tie plate or clamp which passes 
 over the end of the strut and is bound firmly against 
 the surface of the frame piece by the eye bolts of the 
 stanchion sockets. 
 
 Placing the Rib Pieces. 
 
 Take one of the frames and place on it the ribs, with 
 the arched side up, letting one end of the ribs come 
 
 Various Methods of Attaching Stanchions and Guy Wires. 
 
 flush with the front edge of the forward frame, and the 
 other end projecting about a foot beyond the rear frame. 
 The manner of fastening the ribs to the frame pieces is 
 optional. In some cases they are lashed with shoe 
 thread, and in others clamped with a metal clamp fast- 
 ened with i^-inch wood screws. Where clamps and 
 screws are used care should be taken to make slight 
 holes in the wood with an awl before starting the screws 
 so as to lessen any tendency to split the wood. On the 
 top frame, twenty-one ribs placed one foot apart will be 
 
40 FLYING MACHINES: 
 
 required. On the lower frame, because of the opening 
 left for the operator's body, you will need only twenty. 
 
 Joining the Two Frames. 
 
 The two frames must now be joined together. For this 
 you will need twenty-four aluminum or iron sockets 
 which may be purchased at a foundry or hardware shop. 
 These sockets, as the name implies, provide a receptacle 
 in which the end of a stanchion is firmly held, and have 
 flanges with holes for eye-bolts w r hich hold them firmly 
 to the frame pieces, and also serve to hold the guy wires. 
 In addition to these eye-bolt holes there are two others 
 through which screws are fastened into the frame pieces. 
 On the front frame piece of the bottom plane place six 
 sockets, beginning at the end of the frame, and locating 
 them exactly opposite the struts. Screw the sockets into 
 position with wood screws, and then put the eye-bolts in 
 place. Repeat the operation on the rear frame. Xext 
 put the sockets for the upper plane frame in place. 
 
 You are now ready to bring the two planes together. 
 Begin by inserting the stanchions in the sockets in the 
 lower plane. The ends may need a little rubbing with 
 sandpaper to get them into the sockets, but care must 
 be taken to have them fit snugly. When all the stan- 
 chions are in place on the lower plane, lift the upper 
 plane into position, and fit the sockets over the upper 
 ends of the stanchions. 
 
 Trussing with Guy Wires. 
 
 The next move is to "tie" the frame together rigidly 
 by the aid of guy wires. This is where the No. 12 piano 
 wire comes in. Each rectangle formed by the struts and 
 stanchions with the exception of the small center one, 
 is to be wired separately as shown in the illustration. 
 At each of the eight corners forming the rectangle the 
 
CONSTRUCTION AND OPERATION 
 
 41 
 
 ring of one of the eye-bolts will be found. There are 
 two ways of doing this "tieing," or trussing. One is to 
 run the wires diagonally from eye-bolt to eye-bolt, de- 
 pending upon main strength to pull them taut enough, 
 and then twist the ends so as to hold. The other is to 
 first make a loop of wire at each eye-bolt, and connect 
 
 Or HUT 
 
 Upper Cut Shows Warping Wires. Lower Cut Shows Method 
 of Fastening Guy Wires. 
 
 these loops to the main wires with turn-buckles. This 
 latter method is the best, as it admits of the tension being 
 regulated by simply turning the buckle so as to draw 
 the ends of the wire closer together. A glance at the 
 illustration will make this plain, and also show how the 
 wires are to be placed. The proper degree of tension 
 may be determined in the following manner: 
 
 After the frame is wired place each end on a saw-horse 
 so as to lift the entire frame clear of the work-shop 
 
42 FLYING MACHINES: 
 
 floor. Get under it, in the center rectangle and, grasping 
 the center struts, one in each hand, put your entire 
 weight on the structure. 'If it is properly put together 
 it will remain rigid and unyielding. Should it sag ever 
 so slightly the tension of the wires must be increased 
 until any tendency to sag, no matter how slight it may 
 be, is overcome. 
 
 Putting on the Cloth. 
 
 We are now ready to put on the cloth covering which 
 holds the air and makes the machine buoyant. The kind 
 of material employed is of small account so long as it is 
 light, strong, and wind-proof, or nearly so. Some avi- 
 ators use. what is called rubberized silk, others prefer 
 balloon cloth. Ordinary muslin of good quality, treated 
 with a coat of light varnish after it is in place, will an- 
 swer all the purposes of the amateur. 
 
 Cut the cloth into strips a little over 4 feet in length. 
 As you have 20 feet in width to cover, and the cloth is 
 one yard wide, you will need seven strips for each plane, 
 so as to allow for laps, etc. This will give you fourteen 
 strips. Glue the end of each strip around the front hor- 
 izontal beams of the planes, and draw each strip back, 
 over the ribs, tacking the edges to the ribs as you go 
 along, with small copper or brass tacks. In doing this 
 keep the cloth smooth and stretched tight. Tacks should 
 also be used in addition to the glue, to hold the cloth to 
 the horizontal beams. 
 
 Next, give the cloth a coat of varnish on the clear, or 
 upper side, and when this is dry your glider will be 
 ready for use. 
 
 Reinforcing the Cloth. 
 
 While not absolutely necessary for amateur purposes, 
 reinforcement of the cloth, so as to avoid any tendency 
 to split or tear out from wind-pressure, is desirable. One 
 
CONSTRUCTION AND OPERATION 
 
 43 
 
44 FLYING MACHINES: 
 
 way of doing this is to tack narrow strips of some 
 heavier material, like felt, over the cloth where it laps 
 on the ribs. Another is to sew slips or pockets in the 
 cloth itself and let the ribs run through them. Still an- 
 other method is to sew 2-inch strips (of the same ma- 
 terial as the cover) on the cloth, placing them about one 
 yard apart, but having them come in the center of each 
 piece of covering, and not on the laps where the various 
 pieces are joined. 
 
 Use of Armpieces. 
 
 Should armpieces be desired, aside from those afforded 
 by the center struts, take two pieces of spruce, 3 feet 
 long, by ixi^4 inches, and bolt them to the front and 
 rear beams of the lower plane about 14 inches apart. 
 These will be more comfortable than using the struts, 
 as the operator will not have to spread his arms so 
 much. In using the struts the operator, as a rule, takes 
 hold of them with his hands, while with the armpieces, 
 as the name implies, he places his arms over them, one 
 of the strips coming under each armpit. 
 
 Frequently somebody asks why the ribs should be 
 curved. The answer is easy. The curvature tends to 
 direct the air downward toward the rear and, as the air 
 is thus forced downward, there is more or less of an im- 
 pact which assists in propelling the aeroplane upwards. 
 
CONSTRUCTION AND OPERATION 
 
 45 
 
 bfl 
 
 03 
 
 a 
 * I 
 
 3 
 >> .b 
 
 
 
 C C 
 nj <u 
 
 o 
 
 O v 
 
 p< 
 
 w. 
 
 * 
 
 O 
 
46 
 
 FLYING MACHINES: 
 
CHAPTER VI. 
 
 LEARNING TO FLY. 
 
 Don't be too ambitious at the start. Go slow, and 
 avoid unnecessary risks. At its best there is an element 
 of danger in aviation which cannot be entirely elimi- 
 
 All Ready for a Glide. 
 
 nated, but it may be greatly reduced and minimized by 
 the use of common sense. 
 
 Theoretically, the proper way to begin a glide is from 
 the top of an incline, facing against the wind, so that 
 
 47 
 
48 FLYING MACHINES: 
 
 the machine will soar until the attraction of gravitation 
 draws it gradually to the ground. This is the manner in 
 which experienced aviators operate, but it must be kept 
 in mind that these men are experts. They understand 
 air currents, know how to control the action and direc- 
 tion of their machines by shifting the position of their 
 bodies, and by so doing avoid accidents which would be 
 unavoidable by a novice. 
 
 Begin on Level Ground. 
 
 Make your first flights on level ground, having a cou- 
 ple of men to assist you in getting the apparatus under 
 headway. Take your position in the center rectangle, 
 back far enough to give the forward edges of the glider 
 an inclination to tilt upward very slightly. Now start 
 and run forward at a moderately rapid gait, one man at 
 each end of the glider assisting you. As the glider cuts 
 into the air the wind will catch under the uplifted edges 
 of the curved planes, and buoy it up so that it will rise 
 in the air and take you with it. This rise will not be 
 great, just enough to keep you well clear' of the ground. 
 Now project your legs a little to the front so as to shift 
 the center of gravity a trifle and bring the edges of the 
 glider on an exact level with the atmosphere. This, with 
 the momentum acquired in the start, will keep the ma- 
 chine moving forward for some distance. 
 
 Effect of Body Movements. 
 
 When the weight of the body is slightly back of the 
 center of gravity the edges of the advancing planes are 
 tilted slightly upward. The glider in this position acts 
 as a scoop, taking in the air which, in turn, lifts it off the 
 ground. When a certain altitude is reached this varies 
 with the force of the wind the tendency to a forward 
 movement is lost and the glider comes to the ground. 
 
CONSTRUCTION AND OPERATION 49 
 
 It is to prolong the forward movement as much as pos- 
 sible that the operator shifts the center of gravity slight- 
 ly, bringing the apparatus on an even keel as it were by 
 lowering the advancing edges. This done, so long as 
 there is momentum enough to keep the glider moving, it 
 will remain afloat. 
 
 If you shift your body well forward it will bring the 
 front edges of the glider down, and elevate the rear ones. 
 
 Biplane in Flight on Even Keel. 
 
 In this way the air will be "spilled" out at the rear, and, 
 having lost the air support or buoyancy, the glider comes 
 down to the ground. A few flights will make any ordi- 
 nary man proficient in the control of his apparatus by his 
 body movements, not only as concerns the elevating and 
 depressing of the advancing edges, but also actual steer- 
 
50 FLYING MACHINES: 
 
 ing. You will quickly learn, for instance, that, as the 
 shifting of the bodily weight backwards and forwards 
 affects the upward and downward trend of the planes, so 
 a movement sideways to the left or the right affects 
 the direction in which the glider travels. 
 
 Ascends at an Angle. 
 
 In ascending, the glider and flying machine, like the 
 bird, makes an angular, not a vertical flight. Just what 
 this angle of ascension may be is difficult to determine. 
 It is probable and in fact altogether likely, that it varies 
 with the force of the wind, weight of the rising body, 
 power of propulsion, etc. This, in the language of phys- 
 icists, is the angle of inclination, and, as a general thing, 
 under normal conditions (still air) should be put down as 
 about one in ten, or 5^4 degrees. This would be an ideal 
 condition, but it has not, as yet been reached. The force 
 of the wind affects the angle considerably, as does also 
 the weight and velocity of the apparatus. In general 
 practice the angle varies from 23 to 45 degrees. At 
 more than 45 degrees the supporting effort is overcome 
 by the resistance to forward motion. 
 
 Increasing the speed or propulsive force, tends to 
 lessen the angle at which the machine may be success- 
 full}'- operated because it reduces the wind pressure. 
 Most of the modern flying machines are operated at an 
 angle of 23 degrees, or less. 
 
 Maintaining an Equilibrium. 
 
 Stable equilibrium is one of the main essentials to 
 successful flight, and this cannot be preserved in an 
 uncertain, gusty wind, especially by an amateur. The 
 novice should not attempt a glide unless the conditions 
 are just right. These conditions are : A clear, level 
 space, without obstructions, such as trees, etc., and a 
 
CONSTRUCTION AND OPERATION 51 
 
 steady wind of not exceeding twelve miles an hour. Al- 
 ways fly against the wind. 
 
 When a reasonable amount of proficiency in the han- 
 dling of the machine on level ground has been acquired 
 the field of practice may be changed to some gentle 
 slope. In starting from a slope it will be found easier 
 
 From Scientific American Supplement. 
 
 Glider Struck by a Side Gust. 
 
 Note how operator seeks to restore equilibrium by shifting his 
 weight toward uplifted end. 
 
 to keep the machine afloat, but the experience at first is 
 likely to be very disconcerting to a man of less than iron 
 nerve. As the glider sails away from the top of the 
 slope the distance between him and the ground increases 
 rapidly until the aviator thinks he is up a hundred miles 
 in the air. If he will keep cool, manipulate his apparatus 
 so as to preserve its equilibrium, and "let nature take its 
 course," he will come down gradually and safely to the 
 ground at a considerable distance from the starting place. 
 
52 
 
 FLYING MACHINES: 
 
 This is one advantage of starting from an elevation 
 your machine will go further. 
 
 But, if the aviator becomes "rattled" ; if he loses con- 
 trol of his machine, serious results, including a bad fall 
 with risk of death, are almost certain. And yet this 
 practice is just as necessary as the initial lessons on 
 level ground. When judgment is used, and "haste made 
 slowly," there is very little real danger. While experi- 
 
 Action of the Vertical Rudder. 
 
 menting with gliders the Wrights made flights innumer- 
 able under all sorts of conditions and never had an acci- 
 dent of any kind. 
 
 Effects of Wind Currents. 
 
 The larger the machine the more difficult it will be to 
 control its movements in the air, and yet enlargement is 
 absolutely necessary as weight, in the form of motor, 
 rudder, etc., is added. 
 
 Air currents near the surface of the ground are di- 
 verted by every obstruction unless the wind is blowing 
 hard enough to remove the obstruction entirely. Take, 
 for instance, the case of a tree or shrub, in a moderate 
 wind of from ten to twelve miles an hour. As the wind 
 strikes the tree it divides, part going to one side and 
 
CONSTRUCTION AND OPERATION 
 
 53 
 
 part going to the other, while still another part is direct- 
 ed upward and goes over the top of the obstruction. 
 This makes the handling of a glider on an obstructed 
 field difficult and uncertain. To handle a glider success- 
 fully the place of operation should be clear and the wind 
 moderate and steady. If it is gusty postpone your flight. 
 In this connection it will be well to understand the veloc- 
 ity of the wind, and what it means as shown in the 
 following table : 
 
 Miles per hour Feet per second Pressure per sq. foot 
 
 10 14.7 492 
 
 25 36.7 3.075 
 
 50 73.3 12.300 
 
 100 146.6 49.200 
 
 Biplane Glider with Operator's Seat. 
 
 Pressure of wind increases in proportion to the square 
 of the velocity. Thus wind at 10 miles an hour has four 
 times the pressure of wind at 5 miles an hour. The 
 greater this pressure the large and heavier the object 
 which can be raised. Any boy who has had experience 
 in flying kites can testify to this. High winds, however, 
 
54 FLYING MACHINES: 
 
 are almost invariably gusty and uncertain as to direc- 
 tion, and this makes them dangerous for aviators. It 
 is also a self-evident fact that, beyond a certain stage, 
 the harder the wind blows the more difficult it is to 
 make headway against it. 
 
 Launching Device for Gliders. 
 
 On page 195 will be found a diagram of the various 
 parts of a launcher for gliders, designed and patented 
 by Mr. Octave Chanute. In describing this invention 
 in Aeronautics, Mr. Chanute says: 
 
 "In practising, the track, preferably portable, is gen- 
 erally laid in the direction of the existing wind and 
 the car, preferably a light platform-car, is placed on the 
 track. The truck carrying the winding-drum and its mo- 
 tor is placed to windward a suitable distance say from 
 two hundred to one thousand feet and is firmly blocked 
 or anchored in line with the portable track, which is 
 preferably 80 or 100 feet in length. The flying or gliding 
 machine to be launched with its operator is placed on 
 the platform-car at the leeward end of the portable track. 
 The line, which is preferably a flexible combination 
 wire-and-cord cable, is stretched between the winding- 
 drum on the track and detachably secured to the flying 
 or gliding machine, preferably by means of a trip-hoop, 
 or else held in the hand of the operator, so that the 
 operator may readily detach the same from the flying- 
 machine when the desired height is attained. 
 
 How Glider Is Started. 
 
 "Then upon a signal given by the operator the en- 
 gineer at the motor puts it into operation, gradually in- 
 creasing the speed until the line is wound upon the drum 
 at a maximum speed of, say, thirty miles an hour. The 
 operator of the flying-machine, whether he stands up- 
 
CONSTRUCTION AND OPERATION 55 
 
 right and carries it on his shoulders, or whether he sits 
 or lies down prone upon it, adjusts the aeroplane or 
 carrying surfaces so that the wind shall strike them on 
 the top and press downward instead of upward until 
 the platform-car under action of the winding-drum and 
 line attains the required speed. 
 
 "When the operator judges that his speed is sufficient, 
 and this depends upon the velocity of the wind as well 
 as that of the car moving against the wind, he quickly 
 causes the front of the flying-machine to tip upward, so 
 that the relative wind striking on the under side of the 
 planes or carrying surfaces shall lift the flying machine 
 into the air. It then ascends like a kite to such height 
 as may be desired by the operator, who then trips the 
 hook and releases the line from the machine. 
 
 What the Operator Does. 
 
 "The operator being now free in the air has a certain 
 initial velocity imparted by the winding-drum and line 
 and also a potential energy corresponding to his height 
 above the ground. If the flying or gliding machine is 
 provided with a motor, he can utilize that in his further 
 flight, and if it is a simple gliding machine without 
 motor he can make a descending flight through the air 
 to such distance as corresponds to the velocity acquired 
 and the height gained, steering meanwhile by the de- 
 vices provided for that purpose. 
 
 "The simplest operation or maneuver is to continue 
 the flight straight ahead against the wind ; but it is pos- 
 sible to vary this course to the right or left, or even to 
 return in downward flight with the wind to the vicinity 
 of the starting-point. Upon nearing the ground the 
 operator tips upward his carrying-surfaces and stops his 
 headway upon the cushion of increased air resistance 
 so caused. The operator is in no way permanently 
 
66 FLYING MACHINES: 
 
 fastened to his machine, and the machine and the oper- 
 ator simply rest upon the light platform-car, so that 
 the operator is free to rise with the machine from the 
 car whenever the required initial velocity is attained. 
 
 Motor For the Launcher. 
 
 "The motor may be of any suitable kind or construc- 
 tion, but is preferably an electric or gasolene motor. 
 The winding-drum is furnished with any suitable or cus- 
 tomary reversing-guide to cause the line to wind smoothly 
 and evenly upon the drum. The line is preferably a 
 cable composed of flexible wire and having a cotton or 
 other cord core to increase its flexibility. The line ex- 
 tends from the drum to the flying or gliding machine. 
 Its free end may, if desired, be grasped and held by the 
 operator until the flying-machine ascends to the desired 
 height, when by simply letting go of the line the operator 
 may continue his flight free. The line, however, is pref- 
 erably connected to the flying or gliding machine 
 directly by a trip-hook having a handle or trip lever 
 within reach of the operator, so that when he ascends 
 to the required height he may readily detach the line 
 from the flying or gliding machine." 
 
CHAPTER VII. 
 
 PUTTING ON THE RUDDER. 
 
 Gliders as a rule have only one rudder, and this is in 
 the rear. It tends to keep the apparatus with its head to 
 the wind. Unlike the rudder on a boat it is fixed and 
 immovable. The real motor-propelled flying machine, 
 generally has both front and rear rudders manipulated 
 by wire cables at the will of the operator. 
 
 Allowing that the amateur has become reasonably ex- 
 pert in the manipulation of the glider he should, before 
 constructing an actual flying machine, equip his glider 
 with a rudder. 
 
 Cross Pieces for Rudder Beam. 
 
 To do this he should begin by putting in a cross piece, 
 2 feet long by ij4 x 24 inches between the center struts, 
 in the lower plane. This may be fastened to the struts 
 with bolts or braces. The former method is preferable. 
 On this cross piece, and on the rear frame of the plane 
 itself, the rudder beam is clamped and bolted. This 
 rudder beam is 8 feet n inches long. Having put these 
 in place duplicate them in exactly the same manner and 
 dimensions from the upper frame. The cross pieces on 
 which the ends of the rudder beams are clamped should 
 be placed about one foot in advance of the rear frame 
 beam. 
 
 The Rudder Itself. 
 
 The next step is to construct the rudder itself. This 
 
 57 
 
58 FLYING MACHINES: 
 
 consists of two sections, one horizontal, the other verti- 
 cal. The latter keeps the aeroplane headed into the wind, 
 while the former keeps it steady preserves the equili- 
 brium. 
 
 The rudder beams form the top and bottom frames of 
 the vertical rudder. To these are bolted and clamped 
 two upright pieces, 3 feet, 10 inches in length, and y^ 
 inch in cross section. These latter pieces are placed about 
 two feet apart. This completes the framework of the 
 vertical rudder. See next page (59). 
 
 For the horizontal rudder you will require two strips 
 6 feet long, and four 2 feet long. Find the exact center 
 of the upright pieces on the vertical rudder, and at this 
 spot fasten with bolts the long pieces of the horizontal, 
 placing them on the outside of the vertical strips. Next 
 join the ends of the horizontal strips with the 2-foot 
 pieces, using small screws and corner braces. This done 
 you will have two of the 2-foot pieces left. These go in 
 the center of the horizontal frame, "straddling" the ver- 
 tical strips, as shown in the illustration. 
 
 The framework is to be covered with cloth in the 
 same manner as the planes. For this about ten yards 
 will be needed. 
 
 Strengthening the Rudder. 
 
 To ensure rigidity the rudder must be stayed with 
 guy wires. For this purpose the No. 12 piano wire is 
 the best. Begin by running two of these wires from the 
 top eye-bolts of stanchions 3 and 4, page 37, to rudder 
 beam where it joins the rudder planes, fastening them 
 at the bottom. Then run two wires from the top of the 
 rudder beam at the same point, to the bottom eye-bolts 
 of the same stanchions. This will give you four diag- 
 onal wires reaching from the rudder beam to the top 
 and bottom planes of the glider. Now, from the outer 
 
CONSTRUCTION AND OPERATION 59 
 
 ends of the rudder frame run four similar diagonal wires 
 to the end of the rudder beam where it rests on the 
 cross piece. You will then have eight truss wires 
 strengthening the connection of the rudder to the main 
 body of the glider. 
 
 The framework of the rudder planes is then to be 
 braced in the same way, which will take eight more 
 wires, four for each rudder plane. All the wires are 
 to be connected at one end with turn-buckles so the 
 tension may be regulated as desired. 
 
 In forming the rudder frame it will be well to mortise 
 the corners, tack them together with small nails, and 
 then put in a corner brace in the inside of each joint. 
 In doing this bear in mind that the material to be thus 
 fastened is light, and consequently the lightest of nails, 
 screws, bolts and corner pieces, etc., is necessary. 
 
 Framework of Rudder for Glider. 
 
60 
 
 FLYING MACHINES: 
 
CHAPTER VIII. 
 
 THE REAL FLYING MACHINE. 
 
 We will now assume that you have become proficient 
 enough to warrant an attempt at the construction of a 
 real flying machine one that will not only remain sus- 
 pended in the air at the will of the operator, but make 
 respectable progress in whatever direction he may de- 
 
 General Outline of Curtiss' Main Framework. 
 
 sire to go. The glider, it must be remembered, is not 
 steerable, except to a limited extent, and moves only in 
 one direction against the wind. Besides this its power 
 of flotation suspension in the air is circumscribed. 
 
 Larger Surface Area Required. 
 
 The real flying machine is the glider enlarged, and 
 equipped with motor and propeller. The first thing to 
 do is to decide upon the size required. While a glider 
 
 61 
 
62 FLYING MACHINES: 
 
 of 20 foot spread is large enough to sustain a man it 
 could not under any possible conditions, be made to rise 
 with the weight of the motor, propeller and similar 
 equipment added. As the load is increased so must the 
 surface area of the planes be increased. Just what "this 
 increase in surface area should be is problematical as ex- 
 perienced aviators disagree, but as a general proposition 
 it may be placed at from three to four times the area of 
 a 2o-foot glider. 
 
 Some Practical Examples. 
 
 The Wrights used a biplane 41 feet in spread, and 6 l / 2 
 ft. deep. This, for the two planes, gives a total surface 
 area of 538 square feet, inclusive of auxiliary planes. 
 This sustains the engine equipment, operator, etc., a total 
 weight officially announced at 1,070 pounds. It shows 
 a lifting capacity of about two pounds to the square 
 foot of plane surface, as against a lifting capacity of 
 about YI pound per square foot of plane surface for the 
 2O-foot glider. This same Wright machine is also re- 
 ported to have made a successful flight, carrying a total 
 load of 1,100 pounds, which would be over two pounds 
 for each square foot of surface area, which, with auxil- 
 iary planes, is 538 square feet. 
 
 To attain the same results in a monoplane, the single 
 surface would have to be 60 feet in spread and 9 feet 
 deep. But, while this is the mathematical rule, Bleriot 
 has demonstrated that it does not always hold good. 
 On his record-breaking trip across the English chan- 
 nel, July 25th, 1909, the Frenchman was carried in a 
 monoplane 2.^/2 feet in spread, and with a total sustain- 
 ing surface of 150^ square feet. The total weight of 
 the outfit, including machine, operator and fuel suffi- 
 cient for a three-hour run, was only 660 pounds. With 
 an engine of (nominally) 25 horsepower the distance of 
 21 miles was covered in 37 minutes. 
 
CONSTRUCTION AND OPERATION 63 
 
 Which is the Best? 
 
 Right here an established mathematical quantity is 
 involved. A small plane surface offers less resistance 
 to the air than a large one and consequently can attain 
 a higher rate of speed. As explained further on in this 
 chapter speed is an important factor in the matter of 
 weight-sustaining capacity. A machine that travels one- 
 third faster than another can get along with one-half the 
 
 Framework of Bleriot Monoplane. 
 
 surface area of the latter without affecting the load. See 
 the closing paragraph of this chapter on this point. In 
 theory the construction is also the simplest, but this is 
 not always found to be so in practice. The designing 
 and carrying into execution of plans for an extensive 
 area like that of a monoplane involves great skill and 
 cleverness in getting a framework that will be strong 
 enough to furnish the requisite support without an undue 
 
64 FLYING MACHINES: 
 
 excess of weight. This proposition is greatly simplified 
 in the biplane and, while the speed attained by the latter 
 may not be quite so great as that of the monoplane, it 
 has much larger weight-carrying capacity. 
 
 Proper Sizes For Frame. 
 
 Allowing that the biplane form is selected the con- 
 struction may be practically identical with that of the 
 2o-foot glider described in Chapter V., except as to size 
 and elimination of the armpieces. In size the surface 
 planes should be about twice as large as those of the 
 2O-foot glider, viz : 40 feet spread instead of 20, and 6 feet 
 deep instead of 3. The horizontal beams, struts, stan- 
 chions, ribs, etc., should also be increased in size pro- 
 portionately. 
 
 While care in the selection of clear, straight-grained 
 timber is important in the glider, it is still more im- 
 portant in the construction of a motor-equipped flying 
 machine as the strain on the various parts will be much 
 greater. 
 
 How to Splice Timbers. 
 
 It is practically certain that you will have to resort to 
 splicing the horizontal beams as it will be difficult, if not 
 impossible, to find 4O-foot pieces of timber totally free 
 from knots and worm holes, and of straight grain. 
 
 If splicing is necessary select two good 2O-foot pieces, 
 3 inches wide and iV 2 inches thick, and one lo-foot long, 
 of the same thickness and width. Plane off the bottom 
 sides of the lo-foot strip, beginning about two feet back 
 from each end, and taper them so the strip will be about 
 24 inch thick at the extreme ends. Lay the two 2ofoot 
 beams end to end, and under the joint thus made place 
 the lo-foot strip, with the planed-off ends downward. 
 The joint of the 2O-foot pieces should be directly in the 
 center of the ic-foot piece. Bore ten holes (with a y\- 
 
CONSTRUCTION AND OPERATION 65 
 
 inch augur) equi-distant apart through the 2o-foot 
 strips and the lo-foot strip under them. Through these 
 holes run ^[-inch stove bolts with round, beveled heads. 
 In placing these bolts use washers top and bottom, one 
 between the head and the top beam, and the other be- 
 tween the bottom beam and the screw nut which holds 
 the bolt. Screw the nuts down hard so as to bring the 
 two beams tightly together, and you will have a rigid 
 4O-foot beam. 
 
 Splicing with Metal Sleeves. 
 
 An even better way of making a splice is by tonguing 
 and grooving the ends of the frame pieces and enclosing 
 
 Splicing Beam With Third Piece. 
 
 them in a metal sleeve, but it requires more mechanical 
 skill than the method first named. The operation of 
 tonguing and grooving is especially delicate and calls 
 for extreme nicety of touch in the handling of tools, but 
 if this dexerity is possessed the job will be much more 
 satisfactory than one done with a third timber. 
 
 As the frame pieces are generally about i l / 2 inch in 
 diameter, the tongue and the groove into which the 
 tongue fits must be correspondingly small. Begin by 
 sawing into one side of one of the frame pieces about 4 
 inches back from the end. Make the cut about */ 2 inch 
 deep. Then turn the piece over and duplicate the cut. 
 Next saw down from the end to these cuts. When the 
 
06 FLYING MACHINES: 
 
 sawed-out parts are removed you will have a "tongue" 
 in the end of the frame timber 4 inches long and l /2 inch 
 thick. The next move is to saw out a ^-inch groove in 
 the end of the frame piece which is to be joined. You 
 will have to use a small chisel to remove the ^6-inch bit. 
 This will leave a groove into which the tongue will fit 
 easily. 
 
 Joining the Two Pieces. 
 
 Take a thin metal sleeve this is merely a hollow tube 
 of aluminum or brass open at each end 8 inches long, 
 and slip it over either the tongued or grooved end of one 
 of the frame timbers. It is well to have the sleeve fit 
 
 Splicing Beam With Metal Sleeve. 
 
 snugly, and this may necessitate a sand-papering of the 
 frame pieces so the sleeve will slip on. 
 
 Push the sleeve well back out of the way. Cover the 
 tongue thoroughly with glue, and also put some on the 
 inside of the groove. Use plenty of glue. Now press 
 the tongue into the groove, and keep the ends firmly to- 
 gether until the glue is thoroughly dried. Rub off the 
 joint lightly with sand-paper to remove any of the glue 
 which may have oozed out, and slip the sleeve into place 
 over the joint. Tack the sleeve in position with small 
 copper tacks, and you will have an ideal splice. 
 
CONSTRUCTION AND OPERATION 67 
 
 The same operation is to be repeated on each of the 
 four frame pieces. Two 2O-foot pieces joined in this 
 way will give a substantial frame, but when suitable 
 timber of this kind can not be had, three pieces, each 6 
 feet ii inches long, may be used. This would give 20 
 feet 9 inches, of which 8 inches will be taken up in the 
 two joints, leaving the frame 20 feet I inch long. 
 
 Bicycle Spoke and Nipple for Tightening Guy Wires. 
 
 t 
 
 ^COTTON cova& 
 
 .UB6ER, Oet-B 
 ft* ft"* 
 
 At Left, Substitute for Turnbuckle. At Right, Bleriot's Shock 
 
 Absorber. 
 
68 FLYING MACHINES: 
 
 Installation of Motor. 
 
 Next comes the installation of the motor. The kinds 
 and efficiency of the various types are described in the 
 following chapter (IX). All we are interested in at 
 this point is the manner of installation. This varies 
 according to the personal ideas of the aviator. Thus one 
 man puts his motor in the front of his machine, another 
 places it in the center, and still another finds the rear of 
 the frame the best. All get good results, the comparative 
 advantages of which it is difficult to estimate. Where 
 one man, as already explained, flies faster than another, 
 the one beaten from the speed standpoint has an advan- 
 tage in the matter of carrying weight, etc. 
 
 The ideas of various well-known aviators as to the 
 correct placing of motors may be had from the following : 
 
 Wrights In rear of machine and to one side. 
 
 Curtiss Well to rear, about midway between upper 
 and lower planes. 
 
 Raich In rear, above the center. 
 
 Brauner-Smith In exact center of machine. 
 
 Van Anden In center. 
 
 Herring-Burgess Directly behind operator. 
 
 Voisin In rear, and on lower plane. 
 
 Bleriot In front. 
 
 R. E. P. In front. 
 
 The One Chief Object. 
 
 An even distribution of the load so as to assist in 
 maintaining the equilibrium of the machine, should be 
 the one chief object in deciding upon the location of the 
 motor. It matters little what particular spot is selected 
 so long as the weight does not tend to overbalance the 
 machine, or to "throw it off an even keel/' It is just 
 like loading a vessel, an operation in which the expert 
 
CONSTRUCTION AND OPERATION 
 
 69 
 
 seeks to so distribute the weight of the cargo as to keep 
 the vessel in a perfectly upright position, and prevent a 
 "list" or leaning to one side. The more evenly the cargo 
 is distributed the more perfect will be the equilibrium of 
 
70 FLYING MACHINES: 
 
 the vessel and the better it can be handled. Sometimes, 
 when not properly stowed, the cargo shifts, and this at 
 once affects the position of the craft. When a ship 
 "lists" to starboard or port a preponderating weight of 
 the cargo has shifted sideways ; if bow or stern is unduly 
 depressed it is a sure indication that the cargo has shifted 
 accordingly. In either event the handling of the craft 
 becomes not only difficult, but extremely hazardous. 
 Exactly the same conditions prevail in the handling of a 
 flying machine. 
 
 Shape of Machine a Factor. 
 
 In placing the motor you must be governed largely by 
 the shape and construction of the flying machine frame. 
 If the bulk of the weight of the machine and auxiliaries 
 is toward the rear, then the natural location for the mo- 
 tor will be well to the front so as to counterbalance the 
 excess in rear weight. In the same way if the pre- 
 ponderance of the weight is forward, then the motor 
 should be placed back of the center. 
 
 As the propeller blade is really an integral part of the 
 motor, the latter being useless without it, its placing 
 naturally depends upon the location selected for the 
 motor. 
 
 Rudders and Auxiliary Planes. 
 
 Here again there is great diversity of opinion among 
 aviators as to size, location and form. The striking 
 difference of ideas in this respect is well illustrated in 
 the choice made by prominent makers as follows: 
 
 Voisin horizontal rudder, with two wing-like planes, 
 in front; box-like longitudinal stability plane in rear, 
 inside of which is a vertical rudder. 
 
 Wright large biplane horizontal rudder in front at 
 considerable distance about 10 feet from the main 
 planes; vertical biplane rudder in rear; ends of upper 
 
CONSTRUCTION AND OPERATION 
 
 71 
 
 and lower main planes made flexible so they may be 
 moved. 
 
 Curtiss horizontal biplane rudder, with vertical damp- 
 ing plane between the rudder planes about 10 feet in 
 front of main planes ; vertical rudder in rear ; stabilizing 
 planes at each end of upper main plane. 
 
 AAKTAt- 
 
 Strut Connection, Wire Fastening, Etc., on Van Anden. 
 
 Bleriot V-shaped stabilizing fin, proj-ecting from rear 
 of plane, with broad end outward; to the broad end of 
 this fin is hinged a vertical rudder; horizontal biplane 
 rudder, also in rear, under the fin. 
 
 These instances show forcefully the wide diversity of 
 opinion existing among experienced aviators as to the 
 best manner of placing the rudders and stabilizing, or 
 
72 FLYING MACHINES: 
 
 auxiliary planes, and make manifest how hopeless would 
 be the task of attempting to select any one form and 
 advise its exclusive use. 
 
 Rudder and Auxiliary Construction. 
 
 The material used in the construction of the rudders 
 and auxiliary planes is the same as that used in the main 
 planes spruce for the framework and some kind of 
 rubberized or varnished cloth for the covering. The 
 frames are joined and wired in exactly the same manner 
 as the frames of the main planes, the purpose being to 
 secure the same strength and rigidity. Dimensions of 
 the various parts depend upon the plan adopted and the 
 size of the main plane. 
 
 No details as to exact dimensions of these rudders and 
 auxiliary planes are obtainable. The various builders, 
 while willing enough to supply data as to the general 
 measurements, weight, power, etc., of their machines, 
 appear to have overlooked the details of the auxiliary 
 parts, thinking, perhaps, that these were of no particular 
 import to the general public. In the Wright machine, the 
 rear horizontal and front vertical rudders may be set 
 doAvn as being about one-quarter (probably a little less) 
 the size of the main supporting planes. 
 
 Arrangement of Alighting Gear. 
 
 Most modern machines are equipped with an alighting 
 gear, which not only serves to protect the machine and 
 aviator from shock or injury in touching the ground, but 
 also aids in getting under headway. All the leading 
 makes, with the exception of the Wright, are furnished 
 with a frame carrying from two to five pneumatic rub- 
 ber-tired bicycle wheels. In the Curtiss and Voisin 
 machines one wheel is placed in front and two in the 
 rear. In the Bleriot and other prominent machines the 
 
CONSTRUCTION AND OPERATION 
 
74 FLYING MACHINES: 
 
 reverse is the rule two wheels in front and one in the 
 rear. Farman makes use of five wheels, one in the, 
 extreme rear, and four, arranged in pairs, a little to the 
 front of the center of the main lower plane. 
 
 In place of wheels the Wright machine is equipped 
 with a skid-like device consisting of two long beams 
 attached to the lower plane by stanchions and curving 
 up far in front, so as to act as supports to the horizontal 
 rudder. 
 
 Why Wood Is Favored. 
 
 A frequently asked question is : "Why is not alumi- 
 num, or some similar metal, substituted for wood." 
 Wood, particularly spruce, is preferred because, weight 
 considered, it is much stronger than aluminum, and this 
 is the lightest of all metals. In this connection the fol- 
 lowing table will be of interest : 
 
 Compressive 
 
 AVeight Tensile Strength Strength 
 
 per cubic foot per cubic foot per cr.bic foot 
 Material in Ibs. in Ibs. in Ibs. 
 
 Spruce 25 8,000 5,000 
 
 Aluminum 162 16,000 
 
 Brass (sheet) 510 23,000 12,000 
 
 Steel (tool) 490 100,000 40,000 
 
 Copper (sheet) . 548 30,000 40,000 
 
 As extreme lightness, combined with strength, 
 especially tensile strength, is the great essential in flying- 
 machine construction, it can be readily seen that the 
 use of metal, even aluminum, for the framework, is pro- 
 hibited by its weight. While aluminum has double the 
 strength of spruce wood it is vastly heavier, and thus 
 the advantage it has in strength is overbalanced many 
 times by its weight. The specific gravity of aluminum 
 is 2.50; that of spruce is only 0.403. 
 
CONSTRUCTION AND OPERATION 
 
 75 
 
 Things to Be Considered. 
 
 In laying out plans for a flying machine there are five 
 important points which should be settled upon before 
 the actual work of construction is started. These are: 
 
 First Approximate weight of 'the machine when fin- 
 ished and equipped. 
 
 Second Area of the supporting surface required. 
 
 Third Amount of power that will be necessary to 
 secure the desired speed and lifting capacity. 
 
 Fourth Exact dimensions of the main framework 
 and of the auxiliary parts. 
 
 Loose Joint Connection Device. 
 
 Fifth Size, speed and character of the propeller. 
 
 In deciding upon these it will be well to take into 
 consideration the experience of expert aviators regard- 
 ing these features as given elsewhere. (See Chapter X.) 
 
 Estimating the Weights Involved. 
 
 In fixing upon the probable approximate weight in 
 advance of construction much, of course, must be; as- 
 sumed. This means that it will be a matter of advance 
 
70 FLYING MACHINES: 
 
 estimating. If a two-passenger machine is to be built 
 we will start by assuming the maximum combined 
 weight of the two people to be 350 pounds. Most of 
 the professional aviators are lighter than this. Taking 
 the medium between the weights of the Curtiss and 
 Wright machines we have a net average of 850 pounds 
 for the framework, motor, propeller, etc. This, with 
 the two passengers, amounts to 1,190 pounds. As the 
 machines quoted are in successful operation it will be 
 reasonable to assume that this will be a safe basis to 
 operate on. 
 
 What the Novice Must Avoid. 
 
 This does not mean, however, that it will be safe to 
 follow these weights exactly in construction, but that 
 they will serve merely as a basis to start from. Because 
 an expert can turn out a machine, thoroughly equipped, 
 of 850 pounds weight, it does not follow that a novice 
 can do the same thing. The expert's work is the result 
 of years of experience, and he has learned how to con- 
 struct frames and motor plants of the utmost lightness 
 and strength. 
 
 It will be safer for the novice to assume that he can 
 not duplicate the work of such men as Wright and Cur- 
 tiss without adding materially to the gross weight of 
 the framework and equipment minus passengers. 
 
 How to Distribute the Weight. 
 
 Let us take 1,030 pounds as the net weight of the ma- 
 chine as against the same average in the Wright and 
 Curtiss machines. Now comes the question of distribu- 
 ting this weight between the framework, motor, and 
 other equipment. As a general proposition the frame- 
 work should weigh about tw r ice as much as the complete 
 power plant (this is for amateur work). 
 
CONSTRUCTION AND OPERATION 
 
 77 
 
78 FL YING MA CHINES : 
 
 The word "framework" indicates not only the wooden 
 frames of the main planes, auxiliary planes, rudders, 
 etc., but the cloth coverings as well everything in fact 
 except the engine and propeller. 
 
 On the basis named the framework would weigh 686 
 pounds, and the power plant 344. These figures are 
 liberal, and the results desired may be obtained well 
 within them as the novice will learn as he makes prog- 
 ress in the work. 
 
 Figuring on Surface Area. 
 
 It was Prof. Langley who first brought into promi- 
 nence in connection with flying machine construction the 
 mathematical principle that the larger the object the 
 smaller may be the relative area of support. As ex- 
 plained in Chapter XIII, there are mechanical limits as 
 to size which it is not practical to exceed, but the main 
 principle remains in effect. 
 
 Take two aeroplanes of marked difference in area of 
 surface. The larger will, as a rule, sustain a greater 
 weight in relative proportion to its area than the smaller 
 one, and do the work with less relative horsepower. As 
 a general thing well-constructed machines will average 
 a supporting capacity of one pound for every one-half 
 square foot of surface area. Accepting this as a working 
 rule we find that to sustain a weight of 1,200 pounds 
 machine and two passengers we should have 600 
 square feet of surface. 
 
 Distributing the Surface Area. 
 
 The largest surfaces now in use are those of the 
 Wright, Voisin and Antoinette machines 538 square 
 feet in each. The actual sustaining power of these ma- 
 chines, so far as known, has never been tested to the 
 limit; it is probable that the maximum is considerably 
 in excess of what they have been called upon to show. 
 
CONSTRUCTION AND OPERATION 
 
 79 
 
 Iii actual practice the average is a little over one pound 
 for each one-half square foot of surface area. 
 
 Allowing that 600 square feet of surface will be used, 
 the next question is how to distribute it to the best 
 advantage. This is another important matter in which 
 individual preference must rule. We have seen how 
 the professionals disagree on this point, some using 
 auxiliary planes of large size, and others depending upon 
 
 BEAM SHORT /A/vsr 
 
 STRUT * 
 
 .WlRB. 
 
 STAY 
 
 L-Q 
 
 ' Nlfif* 
 
 w^ r 
 
 \ABCUT 
 
 Wiring and Beam Section of Van Anden Machine. 
 
 smaller auxiliaries with an increase in number so as to 
 secure on a different plan virtually the same amount of 
 surface. 
 
 In deciding upon this feature the best thing to do is 
 to follow the plans of some successful aviator, increasing 
 
80 FLYING MACHINES: 
 
 the area of the auxiliaries in proportion to the increase 
 in the area of the main planes. Thus, if you use 600 
 square feet of surface where the man whose plans you 
 are following uses 500, it is simply a matter of making 
 your planes one-fifth larger all around. 
 
 The Cost of Production. 
 
 Cost of production will be of interest to the amateur 
 who essays to construct a flying machine. Assuming 
 that the size decided upon is double that of the glider 
 the material for the framework, timber, cloth, wire, etc., 
 will cost a little more than double. This is because it 
 must be heavier in proportion to the increased size of 
 the framework, and heavy material brings a larger price 
 than the lighter goods. If we allow $20 as the cost of 
 the glider material it will be safe to put down the cost 
 of that required for a real flying machine framework 
 at $60, provided the owner builds it himself. 
 
 As regards the cost of motor and similar equipment 
 it can only be said that this depends upon the selection 
 made. There are some reliable aviation motors which 
 may be had as low as $500, and there are others which 
 cost as much as $2,000. 
 
 Services of Expert Necessary. 
 
 No matter what kind of a motor may be selected the 
 services of an expert will be necessary in its proper 
 installation unless the amateur has considerable genius 
 in this line himself. As a general thing $25 should be 
 a liberal allowance for this work. No matter how care- 
 fully the engine may be placed and connected it will be 
 largely a matter of luck if it is installed in exactly the 
 proper manner at the first attempt. The chances are 
 that several alterations, prompted by the results of trials, 
 will have to be made. If this is the case the expert's 
 
CONSTRUCTION AND OPERATION 
 
 81 
 
 bill may readily run up 
 to $50. If the amateur 
 is competent to do this 
 part of the wor.k the 
 entire item of $50 may, 
 of course, be cut out. 
 
 As a general propo- 
 sition a fairly satisfac- 
 tory flying machine, 
 one that will actually 
 fly and carry the oper- 
 ator with it, may be 
 constructed for $750, 
 but it will lack the bet- 
 ter qualities which 
 mark the higher priced 
 machines. This com- 
 putation is made on 
 the basis of $60 for ma- 
 terial, $50 for services 
 of expert, $600 for mo- 
 tor, etc., and an allow- 
 ance of $40 for extras. 
 
 No man who has the 
 flying machine germ in 
 his system will be long 
 satisfied with his first 
 moderate price ma- 
 chine, no matter how 
 well it may work. It's 
 the old story of the 
 automobile "bug" over 
 again. The man who 
 starts in with a modest 
 $1,000 automobile in- 
 variably progresses by 
 
82 FLYING MACHINES: 
 
 easy stages to the $4,000 or $5,000 class. The natural 
 tendency is to want the biggest and best attainable 
 within the financial reach of the owner. 
 
 It's exactly the same way with the flying machine 
 convert. The more proficient he becomes in the manipu- 
 lation of his car, the stronger becomes the desire to fly 
 further and stay in the air longer than the rest of his 
 brethren. This necessitates larger, more powerful, and 
 more expensive machines as the work of the germ pro- 
 gresses. 
 
 Speed Affects Weight Capacity. 
 
 Don't overlook the fact that the greater speed you 
 can attain the smaller will be the surface area you can 
 get along with. If a machine with 500 square feet of 
 sustaining surface, traveling at a speed of 40 miles an 
 hour, will carry a weight of 1,200 pounds, we can cut 
 the sustaining surface in half and get along with 250 
 square feet, provided a speed of 60 miles an hour can 
 be obtained. At 100 miles an hour only 80 square feet 
 of surface area w r ould be required. In both instances the 
 weight sustaining capacity will remain the same as with 
 the 500 square feet of surface area 1,200 pounds. 
 
 One of these days some mathematical genius will 
 figure out this problem with exactitude and we will have 
 a dependable table giving the maximum carrying capac- 
 ity of various surface areas at various stated speeds, 
 based on the dimensions of the advancing edges. At 
 present it is largely a matter of guesswork so far as 
 making accurate computation goes. Much depends up- 
 on the shape of the machine, and the amount of surface 
 offering resistance to the wind, etc. 
 
CHAPTER IX. 
 
 SELECTION OF THE MOTOR. 
 
 Motors for flying machines must be light in weight, 
 of great strength, productive of extreme speed, and 
 positively dependable in action. It matters little 
 as to the particular form, or whether air or 
 water cooled, so long as the four features named are 
 secured. There are at least a dozen such motors or 
 engines now in use. All are of the gasolene type, and 
 all possess in greater or lesser degree the desired quali- 
 ties. Some of these motors are : 
 
 Renault 8-cylinder, air-cooled; 50 horse power; 
 weight 374 pounds. 
 
 Fiat 8-cylinder, air-cooled ; 50 horse power ; weight 
 150 pounds. 
 
 Farcot 8-cylinder, air-cooled ; from 30 to 100 horse 
 power, according to bore of cylinders ; weight of smallest, 
 84 pounds. 
 
 R. E. P. io-cylinder, air-cooled; 150 horse power; 
 weight 215 pounds. 
 
 Gnome 7 and 14 cylinders, revolving type, air-cooled ; 
 50 and 100 horse power; weight 150 and 300 pounds. 
 
 Darracq 2 to 14 cylinders, water cooled ; 30 to 200 
 horse power ; weight of smallest, 100 pounds. 
 
 Wright 4-cylinder, water-cooled ; 25 horse power ; 
 weight 200 pounds. 
 
 Antoinette 8 and i6-cylinder, water-cooled ; 50 and 100 
 horse power; weight 250 and 500 pounds. 
 
 E. N. V. 8-cylinder, water-cooled; from 30 to 86 
 
84 FLYING MACHINES: 
 
 horse power, according to bore of cylinder; weight 150 
 to 400 pounds. 
 
 Curtiss 8-cylinder, water-cooled ; 60 horse power ; 
 weight 300 pounds. 
 
 Average Weight Per Horse Power. 
 
 It will be noticed that the Gnome motor is unusually 
 light, being about three pounds to the horse power 
 produced, as opposed to an average of ^ l / 2 pounds per 
 horse power in other makes. This result is secured by 
 the elimination of the fly-wheel, the engine itself revolv- 
 ing, thus obtaining the same effect that would be pro- 
 duced by a fly-wheel. The Farcot is even lighter, being 
 considerably less than three pounds per horse power, 
 which is the nearest approach to the long-sought engine 
 equipment that will make possible a complete flying 
 machine the total weight of which will not exceed one 
 pound per square foot of area. 
 
 How Lightness Is Secured. 
 
 Thus far foreign manufacturers are ahead of Amer- 
 icans in the production of light-weight aerial motors, as 
 is evidenced by the Gnome and Farcot engines, both of 
 which are of French make. Extreme lightness is made 
 possible by the use of fine, specially prepared steel for 
 the cylinders, thus permitting them to be much thinner 
 than if ordinary forms of steel were used. Another big 
 saving in weight is made by substituting what are 
 known as "auto lubricating" alloys for bearings. These 
 alloys are made of a combination of aluminum and mag- 
 nesium. 
 
 Still further gains are made in the use of alloy steel 
 tubing instead of solid rods, and also by the paring away 
 of material wherever it can be dpne without sacrificing 
 strength. This plan, with the exclusive use of the best 
 
CONSTRUCTION AND OPERATION 
 
 85 
 
 grades of steel, regardless of cost, makes possible a 
 marked reduction in weight. 
 
 Multiplicity of Cylinders. 
 
 Strange as it may seem, multiplicity of cylinders does 
 not always add proportionate weight. Because a 4- 
 cylinder motor weighs say 100 pounds, it does not neces- 
 sarily follow that an 8-cylinder equipment will weigh 
 200 pounds. The reason of this will be plain when it 
 
 Tilting Motor on L. A. W. Aeroplane. 
 
 Upper cut shows motor tilted when machine is leaving the 
 ground. Lower cut shows motor in horizontal position when ma- 
 chine is flying. 
 
 is understood that many of the parts essential to a 4- 
 cylinder motor will fill the requirements of an 8-cylinder 
 motor without enlargement or addition. 
 
 Neither does multiplying the cylinders always in- 
 crease the horsepower proportionately. If a 4-cylinder 
 
86 
 
 FLYING MACHINES: 
 
 motor is rated at 25 horsepower it is not safe to take 
 it for granted that double the number of cylinders will 
 give 50 horsepower. Generally speaking, eight cylinders, 
 the bore, stroke and speed being the same, will give 
 double the power that can be obtained from four, but 
 this does not always hold good. Just why this exception 
 should occur is not explainable by any accepted rule. 
 
 Horse Power and Speed. 
 
 Speed is an important requisite in a flying-machine 
 motor, as the velocity of the aeroplane is a vital factor 
 in flotation. At first thought, the propeller and similar 
 
 Method of Attaching Gnome Motor. 
 
 adjuncts being equal, the inexperienced mind would 
 naturally argue that a 5o-horsepower engine should 
 produce just double the speed of one of 25-horsepower. 
 That this is a fallacy is shown by actual performances. 
 The Wrights, using a 25-horsepower motor, have made 
 44 miles an hour, while Bleriot, with a 5O-horsepower 
 motor, has a record of a short-distance flight at the rate 
 of 52 miles an hour. The fact is that, so far as speed 
 is concerned, much depends upon the velocity of the 
 wind, the size and shape of the aeroplane itself, and the 
 
CONSTRUCTION AND OPERATION 
 
 87 
 
 O CQ 
 
 II 
 
 o< .. 
 
 O ^ 
 
 2 P 
 
 O 
 
 I 
 
 O cs 
 
 S 
 
 o 5 
 
 1 i 
 
88 FLYING MACHINES: 
 
 size, shape and gearing of the propeller. The stronger 
 the wind is blowing the easier it will be for the aero- 
 plane to ascend, but at the same time the more difficult 
 it will be to make headway against the wind in a hori- 
 zontal direction. With a strong head wind, and proper 
 engine force, your machine will progress to a certain 
 extent, but it will be at an angle. If the aviator desired 
 to keep on going upward this would be all right, but 
 there is a limit to the altitude which it is desirable to 
 reach from 100 to 500 feet for experts and after that 
 it becomes a question of going straight ahead. 
 
 Great Waste of Power. 
 
 One thing is certain even in the most efficient of 
 modern aerial motors there is a great loss of power be- 
 tween the two points of production and effect. The 
 Wright outfit, which is admittedly one of the most ef- 
 fective in use, takes one horsepower of force for the rais- 
 ing and propulsion of each 50 pounds of weight. This, 
 for a 25-horsepower engine, would give a maximum lift- 
 ing capacity of 1250 pounds. It is doubtful if any of the 
 higher rated motors have greater efficiency. As an 8- 
 cylinder motor requires more fuel to operate than a 4- 
 cylinder, it naturally follows that it is more expensive 
 to run than the smaller motor, and a normal increase in 
 capacity, taking actual performances as a criterion, is 
 lacking. In other words, what is the sense of using an 
 8-cylinder motor when one of 4 cylinders is sufficient? 
 
 What the Propeller Does. 
 
 Much of the efficiency of the motor is due to the form 
 and gearing of the propeller. Here again, as in other 
 vital parts of flying-machine mechanism, we have a wide 
 divergence of opinion as to the best form. A fish makes 
 progress through the water by using its fins and tail ; 
 
CONSTRUCTION AND OPERATION 
 
 89 
 
 a bird makes its way through the air in a similar manner 
 by the use of its wings and tail. In both instances the 
 motive power comes from the body of the fish or bird. 
 
 New French System of Steering by Propeller. 
 
 A motor shaft; B differential; C pinion gear on main shaft 
 A. Two propellers H, H, are used; C gears by which are driven 
 by shafts running from the differential B. These propellers are 
 used in steering. F shows the application of the steering cables 
 
 In place of fins or wings the flying machine is equipped 
 with a propeller, the action of which is furnished by the 
 engine. Fins and wings have been tried, but they don't 
 work. 
 
90 FLYING MACHINES: 
 
 While operating on the same general principle, aerial 
 propellers are much larger than those used on boats. 
 This is because the boat propeller has a denser, more 
 substantial medium to work in (water), and consequent- 
 ly can get a better "hold," and produce more propulsive 
 force than one of the same size revolving in the air. 
 This necessitates the aerial propellers being much larger 
 than those employed for marine purposes. Up to this 
 point all aviators agree, but as to the best form most of 
 them differ. 
 
 Kinds of Propellers Used. 
 
 One of the most simple is that used by Curtiss. It 
 consists of two pear-shaped blades of laminated wood, 
 each blade being 5 inches wide at its extreme point, 
 tapering slightly to the shaft connection. These blades 
 are joined at the engine shaft, in a direct line. The pro- 
 peller has a pitch of 5 feet, and weighs, complete, less 
 than 10 pounds. The length from end to end of the two 
 blades is 6y 2 feet. 
 
 Wright uses two wooden propellers, in the rear of his 
 biplane, revolving in opposite directions. Each propeller 
 is two-bladed. 
 
 Bleriot also uses a two-blade wooden propeller, but 
 it is placed in front of his machine. The blades are each 
 about 33/2 feet long and have an acute "twist." 
 
 Santos-Dumont uses a two-blade wooden propeller, 
 strikingly similar to the Bleriot. 
 
 On the Antoinette monoplane, with which good records 
 have been made, the propeller consists of two spoon- x 
 shaped pieces of metal, joined at the engine shaft in 
 front, and with the concave surfaces facing the machine. 
 
 The propeller on the Voisin biplane is also of metal, 
 consisting of two aluminum blades connected by a forged 
 steel arm. 
 
 Maximum thrust, or stress exercise of the greatest 
 
CONSTRUCTION AND OPERATION 
 
 91 
 
 air-displacing force is the object sought. This, accord- 
 ing to experts, is best obtained with a large propeller 
 diameter and reasonably low speed. The diameter is the 
 distance from end to end of the blades, which on the 
 largest propellers ranges from 6 to 8 feet. The larger 
 the blade surface the greater will be the volume of air 
 displaced, and, following this, the greater will be the 
 impulse which forces the aeroplane ahead. In all cen- 
 trifugal motion there is more or less tendency to disin- 
 tegration in the form of "flying off" from the center, and 
 
 Seat and Motor on Farman Machine. 
 
 the larger the revolving object is the stronger is this 
 tendency. This is illustrated in the many instances in 
 which big grindstones and fly-wheels have burst from 
 being revolved too fast. To have a propeller break 
 apart in the air would jeopardize the life of the aviator, 
 and to guard against this it has been found best to make 
 its revolving action comparatively slow. Besides this 
 the slow motion (it is only comparatively slow) gives 
 the atmosphere a chance to refill the area disturbed by 
 
92 FLYING MACHINES: 
 
 one propeller blade, and thus have a new surface for 
 the next blade to act upon. 
 
 Placing of the Motor. 
 
 As on other points, aviators differ widely in their 
 ideas as to the proper position for the motor. Wright 
 locates his on the lower plane, midway between the front 
 and rear edges, but considerably to one side of the exact 
 center. He then counter-balances the engine weight by 
 placing his seat far enough away in the opposite direc- 
 tion to preserve the center of gravity. This leaves a 
 space in the center between the motor and the operator 
 in which a passenger may be carried without disturb- 
 ing the equilibrium. 
 
 Bleriot, on the contrary, has his motor directly in 
 front and preserves the center of gravity by taking his 
 seat well back, this, with the weight of the aeroplane, 
 acting as a counter-balance. 
 
 On the Curtiss machine the motor is in the rear, the 
 forward seat of the operator, and weight of the horizon- 
 tal rudder and damping plane in front equalizing the 
 engine weight. 
 
 No Perfect Motor as Yet. 
 
 Engine makers in the United States, England, France 
 and Germany are all seeking to produce an ideal motor 
 for aviation purposes. Many of the productions are 
 highly creditable, but it may be truthfully said that 
 none of them quite fill the bill as regards a combina- 
 tion of the minimum of weight with the maximum of 
 reliable maintained power. They are all, in some re- 
 spects, improvements upon those previously in use, but 
 the great end sought for has not been fully attained. 
 
 One of the motors thus produced was made by the 
 French firm of Darracq at the suggestion of Santos Du- 
 
CONSTRUCTION AND OPERATION 
 
 93 
 
 mont, and on lines laid down by him. Santos Dumont 
 wanted a 2-cylinder horizontal motor capable of devel- 
 oping- 30 horsepower, and not exceeding 4^ pounds per 
 horsepower in weight. 
 
 There can be no question as to the ability and skill 
 
 Propeller and Motor on Voisin Machine. 
 
 of the Darracq people, or of their desire to produce a 
 motor that would bring new credit and prominence to 
 the firm. Neither could anything radically wrong be 
 
94 FLYING MACHINES: 
 
 detected in the plans. But the motor, in at least one 
 important requirement, fell short of expectations. 
 
 It could not be depended upon to deliver an energy 
 of 30 horsepower continuously for any length of time. 
 Its maximum power could be secured only in "spurts." 
 
 This tends to show how hard it is to produce an ideal 
 motor for aviation purposes. Santos Dumont, of un- 
 doubted skill and experience as an aviator, outlined defi- 
 nitely what he wanted ; one of the greatest designers 
 in the business drew the plans, and the famous house of 
 Darracq bent its best energies to the production. But 
 the. desired end was not fully attained. 
 
 Features of Darracq Motor. 
 
 Horizontal motors were practically abandoned some 
 time ago in favor of the vertical type, but Santos Du- 
 mont had a logical reason for reverting to them. He 
 wanted to secure a lower center of gravity than would 
 be possible with a vertical engine. Theoretically his 
 idea was correct as the horizontal motor lies flat, and 
 therefore offers less resistance to the wind, but it did not 
 work out as desired. 
 
 'At the same time it must be admitted that this Dar- 
 racq motor is a marvel of ingenuity and exquisite work- 
 manship. The two cylinders, having a bore of 5 i-io 
 inches and a stroke of 4 7-10 inches, are machined out 
 of a solid bar of steel until their weight is only 8 4-5 
 pounds complete. The head is separate, carrying the 
 seatings for the inlet and exhaust valves, is screwed onto 
 the cylinder, and then welded in position. A copper 
 water-jacket is fitted, and it is in this condition that the 
 weight of 8 4-5 pounds is obtained. 
 
 On long trips, especially in regions where gasolene is 
 hard to get, the weight of the fuel supply is an impor- 
 tant feature in aviation. As a natural consequence flying 
 
CONSTRUCTION AND OPERATION 95 
 
 machine operators favor the motor of greatest economy 
 in gasolene consumption, provided it gives the necessary 
 power. 
 
 An American inventor, Ramsey by name, is working 
 on a motor which is said to possess gfeat possibilities 
 in this line. Its distinctive features include a connecting 
 
 Sectional View of Ramsey Motor. 
 
 rod much shorter than usual, and a crank shaft located 
 the length of the crank from the central axis of the 
 cylinder. This has the effect of increasing the piston 
 stroke, and also of increasing the proportion of the 
 crank circle during which effective pressure is applied 
 to the crank. 
 
 Making the connecting rod shorter and leaving the 
 crank mechanism the same would introduce excessive 
 cylinder friction. This Ramsey overcomes by the loca- 
 tion of his crank shaft. The effect of the long piston 
 
96 FLYING MACHINES: 
 
 stroke thus secured, is to increase the expansion of the 
 gases, which in turn increases the power of the engine 
 without increasing the amount of fuel used. 
 
 Propeller Thrust Important. 
 
 There is one great principle in flying machine propul- 
 sion which must not be overlooked. No matter how 
 powerful the engine may be unless the propeller thrust 
 more than overcomes the wind pressure there can be 
 no progress forward. Should the force of this propeller 
 thrust and that of the wind pressure be equal the re- 
 sult is obvious. The machine is at a stand-still so far 
 as forward progress is concerned and, deprived of the 
 essential advancing movement, falls to the ground.^ 
 
 Speed not only furnishes sustentation for the airship, 
 but adds to the stability of the machine. An aeroplane 
 which may be jerky and uncertain in its movements, so 
 far as equilibrium is concerned, when moving at a slow 
 gait, will readily maintain an even keel when the speed 
 is increased. 
 
 Designs for Propeller Blades. 
 
 It is the object of all men who design propellers to 
 obtain the maximum of thrust with the minimum ex- 
 penditure of engine energy. With this purpose in view 
 many peculiar forms of propeller blades have been 
 evolved. In theory it would seem that the best effects 
 could be secured with blades so shaped as to present a 
 thin (or cutting) edge when they come out of the wind, 
 and then at the climax of displacement afford a maxi- 
 mum of surface so as to displace as much air as pos- 
 sible. While this is the form most generally favored 
 there are others in successful operation. 
 
 There is also wide difference in opinion as to the 
 equipment of the propeller shaft with two or more 
 
CONSTRUCTION AND OPERATION 
 
 97 
 
 blades. Some aviators use two and some four. All 
 have more or less success. As a mathematical proposi- 
 tion it would seem that four blades should give more 
 propulsive force than two, but here again comes in one 
 of the puzzles of aviation, as this result is not always 
 obtained. 
 
 Difference in Propeller Efficiency. 
 
 That there is a great difference in propeller efficiency 
 is made readily apparent by the comparison of effects 
 
 r . ft*. i 
 
 Engine and Propeller of Curtiss Biplane. 
 
 produced in two leading makes of machines the Wright 
 and the Voisin. 
 
 In the former a weight of from 1,100 to 1,200 pounds 
 is sustained and advance progress made at the rate of 
 40 miles an hour and more, with half the engine speed 
 of a 25 horse-power motor. This would be a sustaining. 
 
98 FLYING MACHINES: 
 
 capacity of 48 pounds per horsepower. But the actual 
 capacity of the Wright machine, as already stated, is 50 
 pounds per horsepower. 
 
 The Voisin machine, with aviator, weighs about 1,3/0 
 pounds, and is operated with a 5O-horsepower motor. 
 
 One of the Four-Bladed Propellers. 
 
 Allowing it the same speed as the Wright we find that, 
 with double the engine energy, the lifting capacity is 
 only 27^ pounds per horsepower. To what shall we 
 charge this remarkable difference? The surface of the 
 
CONSTRUCTION AND OPERATION 
 
 99 
 
 planes is exactly the same in both machines so there 
 is no advantage in the matter of supporting area. 
 
 Comparison of Two Designs. 
 
 On the Wright machine two wooden propellers of 
 two blades each (each blade having a decided "twist") 
 are used. As one 25 horsepower motor drives both pro- 
 
 A Three-Bladed Propeller. 
 
 pellers the engine energy amounts to just one-half of 
 this for each, or i2 l / 2 horsepower. And this energy is 
 utilized at one-half the normal engine speed. 
 
 On the Voisin a radically different system is employed. 
 Here we have one metal two-bladed propeller with a 
 very slight "twist" to the blade surfaces. The full energy 
 of a 5o-horsepower motor is utilized. 
 
 Experts Fail to Agree. 
 
 Why should there be such a marked difference in 
 the results obtained? Who knows? Some experts 
 
100 FLYING MACHINES: 
 
 maintain that it is because there are two propellers on 
 the Wright machine and only one on the Voisin, and 
 consequently double the propulsive power is exerted. 
 But this is not a fair deduction, unless both propellers 
 are of the same size. Propulsive power depends upon 
 the amount of air displaced, and the energy put into the 
 thrust which displaces the air. 
 
 Other experts argue that the difference in results may 
 
 Sample of Two-Bladed Propeller. 
 
 be traced to the difference in blade design, especially 
 in the matter of "twist." 
 
 The fact is that propeller results depend largely upon 
 the nature of the aeroplanes on which they are used. 
 A propeller, for instance, which gives excellent results 
 on one type of aeroplane, will not work satisfactorily on 
 another. 
 
 Simple Form of Propeller Used by Curtiss. 
 
 There are some features, however, which may be safe- 
 ly adopted in propeller selection. These are : As exten- 
 sive a diameter as possible; blade area 10 to 15 per cent 
 of the area swept ; pitch four-fifths of the diameter ; ro- 
 tation slow. The maximum of thrust effort will be thus 
 obtained. 
 
CHAPTER X. 
 
 PROPER DIMENSIONS OF MACHINES. 
 
 In laying out plans for a flying machine the first thing 
 to decide upon is the size of the plane surfaces. The pro- 
 portions of these must be based upon the load to be 
 carried. This includes the total weight of the machine 
 and equipment, and also the operator. This will be a 
 rather difficult problem to 'figure out exactly, but prac- 
 tical approximate figures may be reached. 
 
 It is easy to get at the weight of the operator, motor 
 and propeller, but the matter of determining, before they 
 are constructed, what the planes, rudders, auxiliaries, 
 etc., will weigh when completed is an intricate proposi- 
 tion. The best way is to take the dimensions of some 
 successful machine and use them, making such altera- 
 tions in a minor way as you may desire. 
 
 Dimensions of Leading Machines. 
 
 In the following tables will be found the details as to 
 surface area, weight, power, etc., of the nine principal 
 types of flying machines which are now prominently be- 
 fore the public : 
 
 MONOPLANES. 
 
 Make 
 
 Santos-Dumont 
 Bleriot 
 
 Passengers 
 I 
 I 
 
 Surface area 
 sq. feet 
 
 no 
 150.6 
 
 Spread in 
 linear feet 
 
 16.0 
 
 24. 6 
 
 Depth in 
 linear feet 
 
 26.O 
 22.O 
 
 R. E. P 
 
 I 
 
 2m 
 
 ^T- <W 
 
 ^4.1 
 
 28.Q 
 
 Bleriot 
 
 ... .2 
 
 j 
 236 
 
 vTT 
 "32. Q 
 
 .7 
 2^.O 
 
 Antoinette . . . . , 
 
 , . . . .2 
 
 "O 
 
 S^8 
 
 O .7 
 
 41.2 
 
 "O 
 
 ^7.Q 
 
 
 
 JO 
 
 101 
 
 *f * fffH 
 
 O/ '.7 
 
102 
 
 FLYING MACHINES: 
 
 \o, of 
 Make Cylinders 
 
 Santos-Dumont 2 
 
 Bleriot 3 
 
 R. E. P 7 
 
 Bleriot 8 
 
 Antoinette ..8 
 
 Weight Without 
 Horse Power Operator 
 
 30 
 25 
 35 
 50 
 50 
 
 BIPLANES. 
 
 Surface Area 
 Passengers sq. feet 
 
 Make 
 
 Curtiss 2 
 
 Wright 2 
 
 Farman 2 
 
 Voisin 2 
 
 No. of 
 Make Cylinders 
 
 Curtiss .8 
 
 Wright 4 
 
 Farman 7 
 
 Voisin ..8 
 
 258 
 538 
 430 
 538 
 
 250 
 
 680 
 
 900 
 
 1,240 
 
 1,040 
 
 Spread in 
 linear feet 
 
 29.0 
 4I.O 
 32.9 
 
 37-9 
 
 Horse Power 
 50 
 
 Weight Without 
 Operator 
 
 600 
 
 25 
 
 I,IOO 
 
 50 
 
 1,200 
 
 50 
 
 I,2OO 
 
 Propeller 
 Diameter 
 
 6.9 
 
 6.6 
 8.1 
 7.2 
 
 Depth in 
 linear feet 
 
 28.7 
 30-7 
 
 39-6 
 39- 6 
 
 Propeller 
 Diameter 
 
 6.0 
 8.1 
 8.9 
 6.6 
 
 In giving the depth dimensions the length over all 
 from the extreme edge of the front auxiliary plane to 
 the extreme tip of the rear is stated. Thus while the 
 dimensions of the main planes of the Wright machine 
 are 41 feet spread by 6 l / 2 feet in depth, the depth over 
 all is 30.7. 
 
 Figuring Out the Details. 
 
 With this data as a guide it should be comparatively 
 easy to decide upon the dimensions of the machine re- 
 quired. In arriving at the maximum lifting capacity the 
 weight of the operator must be added. Assuming this 
 to average 170 pounds the method of procedure would be 
 as follows: 
 
 Add the weight of the operator to the weight of the 
 complete machine. The new Wright machine complete 
 
CONSTRUCTION AND OPERATION 
 
 103 
 
 weighs 900 pounds. This, plus 170, the weight of the 
 operator, gives a total of 1,070 pounds. There are 538 
 square feet of supporting surface, or practically one 
 square foot of surface area to each two pounds of load. 
 
 Method of Carrying Passenger in Wright Machine. 
 
 Placing passenger in center equalizes weight between operator 
 and motor. 
 
 There are some machines, notably the Bleriot, in which 
 the supporting power is much greater. In this latter 
 instance we find a surface area of 150^ square feet 
 carrying a load of 680 plus 170, or an aggregate of 850 
 pounds. This is the equivalent of five pounds to the 
 
104 FLYING MACHINES: 
 
 square foot. This ratio is phenomenally large, and 
 should not be taken as a guide by amateurs. 
 
 The Matter of Passengers. 
 
 These deductions are based on each machine carrying 
 one passenger, which is admittedly the limit at present 
 of the monoplanes like those operated for record-making 
 purposes by Santos-Dumont and Bleriot. The biplanes, 
 however, have a two-passenger capacity, and this adds 
 materially to the proportion of their weight-sustaining 
 power as compared with the surface area. In the fol- 
 lowing statement all the machines are figured on the 
 one-passenger basis. Curtiss and Wright have carried 
 two passengers on numerous occasions, and an extra 170 
 pounds should therefore be added to the total weight 
 carried, which would materially increase the capacity. 
 Even with the two-passenger load the limit is by no 
 means reached, but as experiments have gone no further 
 it is impossible to make more accurate figures. 
 
 Average Proportions of Load. 
 
 It will be interesting, before proceeding to lay out the 
 dimension details, to make a comparison of the propor- 
 tion of load effect with the supporting surfaces of various 
 well-known machines. Here are the figures : 
 
 Santos-Dumont A trifle under four pounds per square 
 foot. 
 
 Bleriot Five pounds. 
 
 R. E. P. Five pounds. 
 
 Antoinette About two and one-quarter pounds. 
 
 Curtiss About two and one-half pounds. 
 
 Wright Two and one-quarter pounds. 
 
 Farman A trifle over three pounds. 
 
 Voisin A little under two and one-half pounds. 
 
CONSTRUCTION AND OPERATION 
 
 105 
 
 Importance of Engine Power. 
 
 While these figures are authentic, they are in a way 
 misleading, as the important factor of engine power 
 is not taken into consideration. Let us recall the fact 
 that it is the engine power which keeps the machine in 
 motion, and that it is only while in motion that the ma- 
 chine will remain suspended in the air. Hence, to at- 
 
 Striking Similarity in Skeletons of Man and Bird. 
 
 Skeleton of bird enlarged for purpose of comparison. 
 
 tribute the support solely to the surface area is erroneous. 
 True, that once under headway the planes contribute 
 largely to the sustaining effect, and are absolutely essen- 
 tial in aerial navigation the motor could not rise with- 
 out them still, when it comes to a question of weight- 
 sustaining power, we must also figure on the engine 
 capacity. 
 
106 FLYING MACHINES: 
 
 In the Wright machine, in which there is a lifting 
 capacity of approximately 2 1 /^ pounds to the square foot 
 of surface area, an engine of only 25 horsepower is used. 
 In the Curtiss, which has a lifting capacity of 2 l / 2 
 pounds per square foot, the engine is of 50 horsepower. 
 This is another of the peculiarities of aerial construction 
 and navigation. Here we have a gain of */J pound in 
 weight-lifting capacity with an expenditure of double 
 the horsepower. It is this feature which enables Curtiss 
 
 
 Curtis Glider, from Which He Developed Aeroplane. 
 
 to get along with a smaller surface area of supporting 
 planes at the expense of a big increase in engine power. 
 
 Proper Weight of Machine. 
 
 As a general proposition the most satisfactory ma- 
 chine for amateur purposes will be found to be one with 
 a total weight-sustaining power of about 1,200 pounds. 
 Deducting 170 pounds as the weight of the operator, 
 this will leave 1,030 pounds for the complete motor- 
 equipped machine, and it should be easy to construct one 
 within this limit. This implies, of course, that due care 
 
CONSTRUCTION AND OPERATION 
 
 107 
 
 will be taken to eliminate all superfluous weight by using 
 the lightest material compatible with strength and safety. 
 This plan will admit of 686 pounds weight in the 
 frame work, coverings, etc., and 344 for the motor, 
 propeller, etc., which will be ample. Just how to dis- 
 tribute the weight of the planes is a matter which must 
 be left to the ingenuity of the builder. 
 
 Comparison of Wing Surface of Albatross and Vulture. 
 
 Comparison of Bird Power. 
 
 There is an interesting study in the accompanying 
 illustration. Note that the surface area of the albatross 
 is much smaller than that of the vulture, although the 
 wing spread is about the same. Despite this the alba- 
 tross accomplishes fully as much in the way of flight 
 and soaring as the vulture. Why? Because the alba- 
 
108 FLYING MACHINES: 
 
 tross is quicker and more powerful in action. It is 
 the application of this same principle in flying machines 
 which enables those of great speed and power to get 
 along with less supporting surface than those of slower 
 movement. 
 
 Measurements of Curtiss Machine. 
 
 Some idea of framework proportion may be had from 
 the following description of the Curtiss machine. The 
 main planes have a spread (width) of 29 feet, and are 
 4J/2 feet deep. The front double surface horizontal rud- 
 der is 6x2 feet, with an area of 24 square feet. To the 
 rear of the main planes is a single surface horizontal 
 plane 6x2 feet, with an area of 12 square feet. In con- 
 nection with this is a vertical rudder 2^2 feet square. 
 Two movable ailerons, or balancing planes, are placed 
 at the extreme ends of the upper planes. These are 6x2 
 feet, and have a combined area of 24 square feet. There 
 is also a triangular shaped vertical steadying surface in 
 connection with the front rudder. 
 
 Thus we have a total of 195 square feet, but as the 
 official figures are 258, and the size of the triangular- 
 shaped steadying surface is unknown, we must take it 
 for granted that this makes up the difference. In the 
 matter of proportion the horizontal double-plane rudder 
 is about one-tenth the size of the main plane, count- 
 ing the surface area of only one plane, the vertical rud- 
 der one-fortieth, and the ailerons one-twentieth. 
 
CHAPTER XI. 
 
 PLANE AND RUDDER CONTROL. 
 
 Having constructed and equipped your machine, the 
 next thing is to decide upon the method of controlling 
 the various rudders and auxiliary planes by which the 
 direction and equilibrium and ascending and descending 
 of the machine are governed. 
 
 The operator must be in position to shift instantane- 
 
 OPCR*TES REAR R.UDDER 
 AND WARPS PLANES 
 
 \ I M E 
 
 >^ CHAIN IS) 
 
 How the Wrights Control Their Machine. 
 
 ously the position of rudders and planes, and also to con- 
 trol the action of the motor. This latter is supposed to 
 work automatically and as a general thing does so with 
 entire satisfaction, but there are times when the supply 
 of gasolene must be regulated, and similar things done. 
 Airship navigation calls for quick action, and for this 
 
 109 
 
110 FLYING MACHINES: 
 
 reason the matter of control is an important one it is 
 more than important; it is vital. 
 
 Several Methods of Control. 
 
 Some aviators use a steering wheel somewhat after 
 the style of that used in automobiles, and by this not 
 only manipulate the rudder planes, but also the flow of 
 gasolene. Others employ foot levers, and still others, 
 like the Wrights, depend upon hand levers. 
 
 Curtiss steers his aeroplane by means of a wheel, but 
 secures the desired stabilizing effect with an ingenious 
 jointed chair-back. This is so arranged that by leaning 
 toward the high point of his wing planes the aeroplane 
 is restored to an even keel. The steering post of the 
 wheel is movable backward and forward, and by this 
 motion elevation is obtained. 
 
 The Wrights for some time used two hand levers, one 
 to steer by and warp the flexible tips of the planes, the 
 other to secure elevation. They have now consolidated 
 all the functions in one lever. Bleriot also uses the 
 single lever control. 
 
 Farman employs a lever to actuate the rudders, but 
 manipulates the balancing planes by foot levers. 
 
 Santos-Dumont uses two hand levers with which to 
 steer and elevate, but manipulates the planes by means 
 of an attachment to the back of his outer coat. (See il- 
 lustration, page in). 
 
 Connection With the Levers. 
 
 No matter which particular method is employed, the 
 connection between the levers and the object to be ma- 
 nipulated is almost invariably by wire. For instance, from 
 the steering levers (or lever) two wires connect with op- 
 posite sides of the rudder. As a lever is moved so as to 
 draw in the right-hand wire the rudder is drawn to the 
 
CONSTRUCTION AND OPERATION 111 
 
 right and vice versa. The operation is exactly the same 
 as in steering a boat. It is the same way in changing 
 the position of the balancing planes. A movement of 
 the hands or feet and the machine has changed its 
 course, or, if the equilibrium is threatened, is back on 
 an even keel. 
 
 Simple as this seems it calls for a cool head, quick 
 
 Device on Back of Santos-Dumont's Shirt. 
 
 Wires run from this in both directions so the auxiliary planes 
 may be manipulated by a mere movement of the body to the right 
 or left. 
 
 eye, and steady hand. The least hesitation or a false 
 movement, and both aviator and craft are in danger. 
 
 Which Method is Best? 
 
 It would be a bold man who would attempt to pick 
 out any one of these methods of control and say it was 
 better than the others. As in other sections of aeroplane 
 mechanism each method has its advocates who dwell 
 learnedly upon its advantages, but the fact remains that 
 all the various plans work well .and give satisfaction. 
 
112 
 
 FLYING MACHINES. 
 
 13 
 
 o fa - 
 
 J_, rO 03 
 
 H ^ 
 
 a 02 
 
 ffl 
 
 a s 
 
 03 
 
CONSTRUCTION AND OPERATION 113 
 
 What the novice is interested in knowing- is how the 
 control is effected, and whether he has become proficient 
 enough in his manipulation of it to be absolutely de- 
 pendable in time of emergency. No amateur should at- 
 tempt a flight alone, until he has thoroughly mastered 
 the steering and plane control. If the services and ad- 
 
 System of Control on Farman Machine. 
 
 vice of an experienced aviator are not to be had the 
 novice should mount his machine on some suitable sup- 
 ports so it will be well clear of the ground, and, getting 
 into the operator's seat, proceed to make himself well 
 acquainted with the operation of the steering wheel and 
 levers. 
 
 Some Things to Be Learned. 
 
 He will soon learn that certain movements of the 
 steering gear produce certain effects on the rudders. If, 
 for instance, his machine is equipped with a steering 
 wheel, he will find that turning the wheel to the right 
 turns the aeroplane in the same direction, because the 
 
114 
 
 FLYING MACHINES: 
 
 rudder is brought around to the left. In the same way 
 he will learn that a given movement of the lever throws 
 the forward edge of the main plane upward, and that the 
 machine, getting the impetus of the wind under the con- 
 cave surfaces of the planes, will ascend. In the same 
 way it will quickly become apparent to him that an op- 
 posite movement of the lever will produce an opposite 
 effect the forward edges of the planes will be lowered, 
 the air will be "spilled" out to the rear, and the machine 
 will descend. 
 
 The time expended in these preliminary lessons will 
 be well spent. It would be an act of folly to attempt to 
 actually sail the craft without them. 
 
 Control System on Voisin Machine. 
 
CHAPTER XII. 
 
 HOW TO USE THE MACHINE. 
 
 It is a mistaken idea that flying machines must be 
 operated at extreme altitudes. True, under the impetus 
 of handsome prizes, and the incentive to advance scien- 
 tific knowledge, professional aviators have ascended to 
 
 Operator's Weight in Center Keeps Machine Level. 
 
 considerable heights, flights at from 500 to 1,500 feet be- 
 ing now common with such experts as Farman, Bleriot, 
 Latham, Paulhan, Wright and Curtiss. The altitude 
 record at this time is about 4,165 feet, held by Paulhan. 
 One of the instructions given by experienced aviators 
 to pupils, and fojr which they insist upon implicit obey- 
 
 115 
 
116 FLYING MACHINES: 
 
 ance, is : "If your machine gets more than 30 feet high, 
 or comes closer to the ground than 6 feet, descend at 
 once." Such men as Wright and Curtiss will not tol- 
 erate a violation of this rule. If their instructions are 
 not strictly complied with they decline to give the of- 
 fender further lessons. 
 
 Why This Rule Prevails. 
 
 There is good reason for this precaution. The higher 
 the altitude the more rarefied (thinner) becomes the air, 
 and the less sustaining power it has. Consequently the 
 more difficult it becomes to keep in suspension a given 
 weight. When sailing within 30 feet of the ground sus- 
 tentation is comparatively easy and, should a fall occur, 
 the results are not likely to be serious. On the other 
 hand, sailing too near the ground is almost as objection- 
 able in many ways as getting up too high. If the craft 
 is navigated too close to the ground trees, shrubs, fences 
 and other obstructions are liable to be encountered. 
 There is also the handicap of contrary air currents 
 diverted by the obstructions referred to, and which will 
 be explained more fully further on. 
 
 How to Make a Start. 
 
 Taking it for granted that the beginner has familiarized 
 himself with the manipulation of the machine, and es- 
 pecially the control mechanism, the next thing in order 
 is an actual flight. It is probable that his machine will 
 be equipped with a wheeled alighting gear, as the skids 
 used by the Wrights necessitate the use of a special 
 starting track. In this respect the wheeled machine is 
 much easier to handle so far as novices are concerned 
 as it may be easily rolled to the trial grounds. This, 
 as in the case of the initial experiments, should be a 
 clear, reasonably level place, free from trees, fences, 
 
CONSTRUCTION AND OPERATION 117 
 
 rocks and similar obstructions with which there may be 
 danger of colliding. 
 
 The beginner will need the assistance of three men. 
 One of these should take his position in the rear of the 
 machine, and one at each end. On reaching the trial 
 ground the aviator takes his seat in the machine and, 
 while the men at the ends keep it steady the one in the 
 rear pushes it along briskly for some distance. In the 
 
 Operator's Weight Back of Center Tilts Planes Upward. 
 
 meantime the aviator has started his motor. Like the 
 glider the flying machine, in order to accomplish the 
 desired results, should be headed into the wind. 
 
 When the Machine Rises. 
 
 Under the impulse of the pushing movement, and as- 
 sisted by the motor action, the machine will gradually 
 rise from the ground provided it has been properly pro- 
 portioned and put together, and everything is in work- 
 ing order. This is the time when the aviator requires 
 a cool head. At a modest distance from the ground use 
 
118 FLYING MACHINES: 
 
 the control lever to bring the machine on a horizontal 
 level and overcome the tendency to rise. The exact 
 manipulation of this lever depends upon the method of 
 control adopted, and with this the aviator is supposed 
 to have thoroughly familiarized himself as previously 
 advised in Chapter XL 
 
 It is at this juncture that the operator must act 
 promptly, but with the perfect composure begotten of 
 confidence. One of the great drawbacks in aviation by 
 novices is the tendency to become rattled, and this is 
 much more prevalent than one might suppose, even 
 among men who, under other conditions, are cool and 
 confident in their actions. 
 
 There is something in the sensation of being suddenly 
 lifted from the ground, and suspended in the air that is 
 disconcerting at the start, but this will soon wear off if 
 the experimenter will keep cool. A few successful flights 
 no matter how short they may be, will put a lot of 
 confidence into him. 
 
 Make Your Flights Short. 
 
 Be modest in your initial flights. Don't attempt to 
 match the records of experienced men who have devoted 
 years to mastering the details of aviation. Paulhan, 
 Farman, Bleriot, Wright, Curtiss, and all the rest of 
 them began, and practiced for years, in the manner here 
 described, being content to make just a little advance- 
 ment at each attempt. A flight of 150 feet, cleanly and 
 safely made, is better as a beginning than one of 400 
 yards full of bungling mishaps. 
 
 And yet these latter have their uses, provided the 
 operator is of a discerning mind and can take advantage 
 of them as object lessons. But, it is not well to invite 
 them. They will occur frequently enough under the 
 most favorable conditions, and it is best to have them 
 
CONSTRUCTION AND OPERATION 110 
 
 come later when the feeling of trepidation and uncer- 
 tainty as to what to do has worn off. 
 
 Above all, don't attempt to fly too high. Keep within 
 a reasonable distance from the ground about 25 or 30 
 feet. This advice is not given solely to lessen the risk 
 of serious accident in case of collapse, but mainly be- 
 cause it will assist to instill confidence in the operator. 
 
 Operator's Weight Forward of Center Depresses Planes. 
 
 It is comparatively easy to learn to swim in shallow 
 water, but the knowledge that one is tempting death in 
 deep water begets timidity. 
 
 Preserving the Equilibrium. 
 
 After learning how to start and stop, to ascend and 
 descend, the next thing to master is the art of preserving 
 equilibrium, the knack of keeping the machine perfectly 
 level in the air on an "even keel," as a sailor would 
 say. This simile is particularly appropriate as all avia- 
 tors are in reality sailors, and much more daring ones 
 
120 FLYING MACHINES: 
 
 than those who course the seas. The latter are in craft 
 which are kept afloat by the buoyancy of the water, 
 whether in motion or otherwise and, so long as normal 
 conditions prevail, will not sink. Aviators sail the air 
 in craft in which constant motion must be maintained in 
 order to ensure flotation. 
 
 The man who has ridden a bicycle or motorcycle 
 around curves at anything like high speed, will have a 
 very good idea as to the principle of maintaining equilib- 
 rium in an airship. He knows that in rounding curves 
 rapidly there is a marked tendency to change the direc- 
 tion of the motion which will result in an upset unless 
 he overcomes it by an inclination of his body in an op- 
 posite direction. This is why we see racers lean well 
 over when taking the curves. It simply must be done 
 to preserve the equilibrium and avoid a spill. 
 
 How It Works In the Air. 
 
 If the equilibrium of an airship is disturbed tp an 
 extent which completely overcomes the center of gravity 
 it falls according to the location of the displacement. 
 If this displacement, for instance, is at either end the 
 apparatus falls endways ; if it is to the front or rear, the 
 fall is in the corresponding direction. 
 
 Owing to uncertain air currents the air is continually 
 shifting and eddying, especially within a hundred feet or 
 so of the earth the equilibrium of an airship is almost 
 constantly being disturbed to some extent. Even if this 
 disturbance is not serious enough to bring on a fall it 
 interferes with the progress of the machine, and should 
 be overcome at once. This is one of the things con- 
 nected with aerial navigation which calls for prompt, 
 intelligent action. 
 
 Frequently, when the displacement is very slight, it 
 may be overcome, and the craft immediately righted by 
 
CONSTRUCTION AND OPERATION 
 
 121 
 
 a mere shifting of the operator's body. Take, for il- 
 lustration, a case in which the extreme right end of the 
 machine becomes lowered a trifle from the normal level. 
 It is possible to bring it back into proper position by 
 leaning over to the left far enough to shift the weight 
 to the counter-balancing point. The same holds good as 
 to minor front or rear displacements. 
 
 When Planes Must Be Used. 
 
 There are other displacements, however, and these are 
 the most frequent, which can be only overcome by man- 
 
 Equilibrium Paradox Explained. 
 
 ipulation of the stabilizing planes. The method of pro- 
 cedure depends upon the form of machine in use. The 
 Wright machine, as previously explained, is equipped 
 with plane ends which are so contrived as to admit of 
 
122 FLYING MACHINES: 
 
 their being warped (position changed) by means of the 
 lever control. These flexible tip planes move simultane- 
 ously, but in opposite directions. As those on one end 
 rise, those on the other end fall below the level of the 
 main plane. By this means air is displaced at one point, 
 and an increased amount secured in another. 
 
 This may seem like a complicated system, but its 
 workings are simple when once understood. It is by 
 the manipulation or warping of these flexible tips that 
 transverse stability is maintained, and any tendency to 
 displacement endways is overcome. Longitudinal sta- 
 bility is governed by means of the front rudder. 
 
 Stabilizing planes of some form are a feature, and a 
 necessary feature, on all flying machines, but the methods 
 of application and manipulation vary according to the 
 individual ideas of the inventors. They all tend, how- 
 ever, toward the same end the keeping of the machine 
 perfectly level when being navigated in the air. 
 
 When to Make a Flight. 
 
 A beginner should never attempt to make a flight 
 when a strong wind is blowing. The fiercer the wind, 
 the more likely it is to be gusty and uncertain, and the 
 more difficult it will be to control the machine. Even 
 the most experienced and daring of aviators find there 
 is a limit to wind speed against which they dare not 
 compete. This is not because they lack courage, but 
 have the sense to realize that it would be silly and use- 
 less. 
 
 The novice will find a comparatively still day, or one 
 when the wind is blowing at not to exceed 15 miles an 
 hour, the best for his experiments. The machine will be 
 more easily controlled, the trip will be safer, and also 
 cheaper as the consumption of fuel increases with the 
 speed of the wind against which the aeroplane is forced. 
 
CHAPTER XIII. 
 
 PECULIARITIES OF AIRSHIP POWER. 
 
 As a general proposition it takes much more power to 
 propel an airship a given number of miles in a certain 
 time than it does an automobile carrying a far heavier 
 load. Automobiles with a gross load of 4,000 pounds, 
 and equipped with engines of 30 horsepower, have trav- 
 elled considerable distances at the rate of 50 miles an 
 hour. This is an equivalent of about 134 pounds per 
 horsepower. For an average modern flying machine, 
 with a total load, machine and passengers, of 1,200 
 pounds, and equipped with a 5o-horsepower engine, 50 
 miles an hour is the maximum. Here we have the equiv- 
 alent of exactly 24 pounds per horsepower. Why this 
 great difference? 
 
 No less an authority than Mr. Octave Chanute answers 
 the question in a plain, easily understood manner. He 
 says : 
 
 "In the case of an automobile the ground furnishes a 
 stable support; in the case of a flying machine the engine 
 must furnish the support and also velocity by which the 
 apparatus is sustained in the air." 
 
 Pressure of the Wind. 
 
 Air pressure is a big factor in the matter of aeroplane 
 horsepower. Allowing that a dead calm exists, a body 
 moving in the atmosphere creates more or less resist- 
 ance. The faster it moves, the greater is this resistance. 
 Moving at the rate of 60 miles an hour the resistance, 
 
 123 
 
124 FLYING MACHINES: 
 
 or wind pressure, is approximately 50 pounds to the 
 square foot of surface presented. If the moving object 
 is advancing at a right angle to the wind the following 
 table will give the horsepower effect of the resistance 
 per square foot of surface at various speeds. 
 
 Horse Power 
 Miles per Hour per sq. foot 
 
 10 0.013 
 
 15 0.044 
 
 20 0.105 
 
 25 0.205 
 
 30 0.354 
 
 40 0.84 
 
 50 1.64 
 
 60 2.83 
 
 80 6.72 
 
 ioo 13.12 
 
 While the pressure per square foot at 60 miles an hour, 
 is only 1.64. horsepower, at ioo miles, less than double 
 the speed, it has increased to 13.12 horsepower, or ex- 
 actly eight times as much. In other words the pressure 
 of the wind increases with the square of the velocity. 
 Wind at 10 miles an hour has four times more pressure 
 than wind at 5 miles an hour. 
 
 How to Determine Upon Power. 
 
 This element of air resistance must be taken into con- 
 sideration in determining the engine horsepower re- 
 quired. When the machine is under headway sufficient 
 to raise it from the ground (about 20 miles an hour), 
 each square foot of surface resistance, will require nearly 
 nine-tenths of a horsepower to overcome the wind pres- 
 sure, and propel the machine through the air. As 
 shown in the table the ratio of power required increases 
 
CONSTRUCTION AND OPERATION 125 
 
 rapidly as the speed increases until at 60 miles an hour 
 approximately 3 horsepower is needed. 
 
 In a machine like the Curtiss the area of wind-exposed 
 surface is about 15 square feet. On the basis of this re- 
 sistance moving the machine at 40 miles an hour would 
 require 12 horsepower. This computation covers only 
 
 ! *%WW 1 -' 
 
 "r 
 
 One of the Early Multiplane Gliders. 
 
 the machine's power to overcome resistance. It does 
 not cover the power exerted in propelling the machine 
 forward after the air pressure is overcome. To meet 
 this important requirement Mr. Curtiss finds it neces- 
 sary to use a 5o-horsepower engine. Of this power, as 
 has been already stated, 12 horsepower is consumed 
 in meeting the wind pressure, leaving 38 horsepower 
 for the purpose of making progress. 
 
 The flying machine must move faster than the air to 
 
126 FLYING MACHINES: 
 
 which it is opposed. Unless it does this there can be no 
 direct progress. If the two forces are equal there is no 
 straight-ahead advancement. Take, for sake of illustra- 
 tion, a case in which an aeroplane, which has developed a 
 speed of 30 miles an hour, meets a wind velocity of 
 equal force moving in an opposite direction. What is 
 the result? There can be no advance because it is a 
 contest between two evenly matched forces. The aero- 
 plane stands still.*) The only way to get out of the diffi- 
 culty is for the operator to resort to "tacking," just as 
 a ship captain does when he is caught in a similar pre- 
 dicament. 
 
 Take another case. An aeroplane, capable of making 
 50 miles an hour in a calm, is met by a head wind of 25 
 miles an hour. How much progress does the aeroplane 
 make? Obviously it is 25 miles an hour over the ground. 
 
 Put the proposition in still another way. If the wind 
 is blowing harder than it is possible for the engine power 
 to overcome, the machine will be forced backward. 
 
 Wind Pressure a Necessity. 
 
 While all this is true, the fact remains that wind 
 pressure, up to a certain stage, is an absolute necessity 
 in aerial navigation. The atmosphere itself has very 
 little real supporting power, especially if inactive. If 
 a body heavier than air is to remain afloat it must move 
 rapidly while in suspension. 
 
 One of the best illustrations of this is to be found in 
 skating over thin ice. Every school boy knows that if 
 he moves with speed he may skate or glide in safety 
 across a thin sheet of ice that would not begin to bear 
 his weight if he were standing still. Exactly the same 
 proposition obtains in the case of the flying machine. 
 
 The non-technical reason why the support of the ma- 
 chine becomes easier as the speed increases is that the 
 
CONSTRUCTION AND OPERATION 
 
 127 
 
 sustaining power of the atmosphere increases with the 
 resistance, and the speed with which the object is mov- 
 ing increases this resistance. With a velocity of 12 miles 
 an hour the weight of the machine is practically reduced 
 by 230 pounds. Thus, if under a condition of absolute 
 calm it were possible to sustain a weight of 770 pounds, 
 the same atmosphere would sustain a weight of 1,000 
 pounds moving at a speed of 12 miles an hour. This 
 
 Sccxle fut 
 
 Huffaker's Model Bird for Soaring Experiments. 
 
 sustaining power increases rapidly as the speed increases. 
 While at 12 miles the sustaining power is figured at 
 230 pounds, at 24 miles it is four times as great, or 920 
 pounds. 
 
 Supporting Area of Birds. 
 
 One of the things which all producing aviators seek 
 to copy is the motive power of birds, particularly in their 
 relation to the area of support. Close investigation has 
 established the fact that the larger the bird the less is 
 the relative area of support required to secure a given 
 result. This is shown in the following table : 
 
128 FLYING MACHINES: 
 
 Support- 
 Weight Surface Horse ing area 
 Bird in Ibs. in sq. feet power per Ib. 
 
 Pigeon ..- i.oo 0.7 0.012 0.7 
 
 Wild Goose .... 9.00 2.65 0.026 0.2833 
 
 Buzzard 5.00 5.03 0.015 1.06 
 
 Condor ...17.00 9.85 0.043 -57 
 
 So far as known the condor is the largest of modern 
 birds. It has a wing stretch of 10 feet from tip to tip, a 
 supporting area of about 10 square feet, and weighs 17 
 pounds. It is capable of exerting perhaps 1-30 horse- 
 power. (These figures are, of course, approximate.) 
 Comparing the condor with the buzzard with a wing 
 stretch of 6 feet, supporting area of 5 square feet, and a 
 little over i-ioo horsepower, it may be seen that, broadly 
 speaking, the larger the bird the less surface area (rel- 
 atively) is nee'ded for its support in the air. 
 
 Comparison With Aeroplanes. 
 
 If we compare the bird figures with those made pos- 
 sible by the development of the aeroplane it will be 
 readily seen that man has made a wonderful advance in 
 imitating the results produced by nature. Here are the 
 figures : 
 
 Support - 
 
 Weight Surface Horse ing area 
 
 Machine in Ibs. in sq. feet power per Ib. 
 
 Santos-Dumont ... 350 110.00 30 0.314 
 
 Bleriot 700 150.00 25 0.214 
 
 Antoinette 1,200 538.00 50 0.448 
 
 Curtiss 700 258.00 60 0.368 
 
 Wright *i,ioo 538.00 25 0.489 
 
 Farman 1,200 430.00 50 0.358 
 
 Voisin 1,200 538.00 50 0.448 
 
 *The "Wrights' new machine weighs only 900 pounds. 
 
 While the average supporting surface is in favor of 
 
CONSTRUCTION AND OPERATION 
 
 129 
 
 the aeroplane, this is more than overbalanced by the 
 greater amount of horsepower required for the weight 
 lifted. The average supporting surface in birds is about 
 three-quarters of a square foot per pound. In the aver- 
 age aeroplane it is about one-half square foot per pound. 
 On the other hand the average aeroplane has a lifting 
 capacity of 24 pounds per horsepower, while the buzzard, 
 for instance, lifts 5 pounds with 15-100 of a horsepower. 
 If the Wright machine which has a lifting power of 50 
 
 Other Parts of Huffaker's Bird Model. 
 
 pounds per horsepower should be alone considered the 
 showing would be much more favorable to the aero- 
 plane, but it would not be a fair comparison. 
 
 More Surface, Less Power. 
 
 Broadly speaking, the larger the supporting area the 
 less will be the power required. Wright, by the use of 
 538 square feet of supporting surface, gets along with an 
 engine of 25 horsepower. Curtiss, who uses only 258 
 square feet of surface, finds an engine of 50 horsepower 
 
130 FLYING MACHINES: 
 
 is needed. Other things, such as frame, etc., being equal, 
 it stands to reason that a reduction in the area of sup- 
 porting surface will correspondingly reduce the weight 
 of the machine. Thus we have the Curtiss machine with 
 its 258 square feet of surface, weighing only 600 pounds 
 (.without operator), but requiring double the horsepower 
 of the Wright machine with 538 square feet of surface 
 and weighing 1,100 pounds. This demonstrates in a 
 forceful way the proposition that the larger the surface 
 the less power will be needed. 
 
 But there is a limit, on account of its bulk and awk- 
 wardness in handling, beyond which the surface area 
 cannot be enlarged. Otherwise it might be possible to 
 equip and operate aeroplanes satisfactorily with engines 
 of 15 horsepower, or even less. 
 
 The Fuel Consumption Problem. 
 
 Fuel consumption is a prime factor in the production 
 of engine power. The veriest mechanical tyro knows in 
 a general way that the more power is secured the more 
 fuel must be consumed, allowing that there is no differ- 
 ence in the power-producing qualities of the material 
 used. But few of us understand just what the ratio of 
 increase is, or how it is caused. This proposition is one 
 of keen interest in connection with aviation. 
 
 Let us cite a problem which will illustrate the point 
 quoted : Allowing that it takes a given amount of gaso- 
 lene to propel a flying machine a given distance, half the 
 way with the wind, and half against it, the wind blow- 
 ing at one-half the speed of the machine, what will be 
 the increase in fuel consumption? 
 
 Increase of Thirty Per Cent 
 
 On the face of it there would seem to be no call for 
 an increase as the resistance met when going against the 
 
CONSTRUCTION AND OPERATION 
 
 131 
 
132 
 
 FLYING MACHINES: 
 
 wind is apparently offset by the propulsive force of the 
 wind when the machine is travelling with it. This, how- 
 ever, is called faulty reasoning. The increase in fuel 
 consumption, as figured by Mr. F. W. Lanchester, of the 
 Royal Society of Arts, will be fully 30 per cent over 
 the amount required for a similar operation of the ma- 
 chine in still air. If the journey should be made at right 
 angles to the wind under the same conditions the in- 
 crease would be 15 per cent. 
 
 In other words Mr. Lanchester maintains that the work 
 done by the motor in making headway against the wind 
 for a certain distance calls for more engine energy, and 
 consequently more fuel by 30 per cent, than is saved by 
 the helping force of the wind on the return journey. 
 
 Front View of New Aerodrome. 
 
 For explanation of figures see cut on page 131. 
 
CHAPTER XIV. 
 
 ABOUT WIND CURRENTS, ETC. 
 
 One of the first difficulties which the novice will en- 
 counter is the uncertainty of the wind currents. With a 
 low velocity the wind, some distance away from the 
 ground, is ordinarily steady. As the velocity increases, 
 
 How Birds Change Direction of Flight. 
 
 however, the wind generally becomes gusty and fitful 
 in its action. This, it should be remembered, does not 
 refer to the velocity of the machine, but to that of the 
 air itself. 
 
 In this connection Mr. Arthur T. Atherholt, president 
 of the Aero Club of Pennsylvania, in addressing the 
 Boston Society of Scientific Research, said : 
 
 "Probably the whirlpools of Niagara contain no more 
 erratic currents than the strata of air which is now im- 
 
 133 
 
134 FLYING MACHINES: 
 
 mediately above us, a fact hard to realize on account 
 of its invisibility." 
 
 Changes In Wind Currents. 
 
 While Mr. Atherholt's experience has been mainly 
 with balloons it is all the more valuable on this account, 
 as the balloons were at the mercy of the wind and their 
 varying directions afforded an indisputable guide as to 
 the changing course of the air currents. In speaking of 
 this he said: 
 
 "In the many trips taken, varying in distance traversed 
 from twenty-five to 900 miles, it was never possible 
 except in one instance to maintain a straight course. 
 These uncertain currents were most noticeable in the 
 Gordon-Bennett race from St. Louis in 1907. Of the 
 nine aerostats competing in that event, eight covered a 
 more or less direct course due east and southeast, where- 
 as the writer, with Major Henry B. Hersey, first started 
 northwest, then north, northeast, east, east by south, and 
 when over the center of Lake Erie were again blown 
 northwest notwithstanding that more favorable winds 
 were sought for at altitudes varying from 100 to 3,000 
 meters, necessitating a finish in Canada nearly northeast 
 of the starting point. 
 
 "These nine balloons, making landings extending from 
 Lake Ontario, Canada, to Virginia, all started from one 
 point within the same hour. 
 
 "The single exception to these roving currents oc- 
 curred on October 2ist, of last year (1909) when, start- 
 ing from Philadelphia, the wind shifted more than eight 
 degrees, the greatest variation being at the lowest alti- 
 tudes, yet at no time was a height of over a mile reached. 
 
 "Throughout the entire day the sky was overcast, with 
 a thermometer varying from fifty-seven degrees at 300 
 feet to forty-four degrees, Fahrenheit at 5,000 feet, at 
 
UNIVERSITY 
 
 OF 
 
 CONSTRUCTION AND OPERATION 
 
 135 
 
 which altitude the wind had a velocity of 43 miles an 
 hour, in clouds of a cirro-cumulus nature, a landing final- 
 ly being made near Tannersville, New York, in the 
 Catskill mountains, after a voyage of five and one-half 
 hours. 
 
 "I have no knowledge of a recorded trip of this dis- 
 tance and duration, maintained in practically a straight 
 line from start to finish." 
 
 This wind disturbance is more noticeable and more 
 
 
 \ 
 
 From Aeronautical Annual. 
 
 Chanute's Multiplane Glider, as Seen from Top. 
 
 difficult to contend with in a balloon than in a flying 
 machine, owing to the bulk and unwieldy character of 
 the former. At the same time it is not conducive to 
 pleasant, safe or satisfactory sky-sailing in an aeroplane. 
 This is not stated with the purpose of discouraging avia- 
 tion, but merely that the operator may know what to 
 expect and be prepared to meet it. 
 
136 FLYING MACHINES: 
 
 Not only does the wind change its horizontal course 
 abruptly and without notice, but it also shifts in a ver- 
 tical direction, one second blowing up, and another 
 down. No man has as yet fathomed the why and where- 
 fore of this erratic action ; it is only known that it exists. 
 
 The most stable currents will be found from 50 to 100 
 feet from the earth, provided the wind is not diverted 
 by such objects as trees, rocks, etc. That there are 
 equally stable currents higher up is true, but they are 
 generally to be found at excessive altitudes. 
 
 How a Bird Meets Currents. 
 
 Observe a bird in action on a windy day and you will 
 find it continually changing the position of its wings. 
 This is done to meet the varying gusts and eddies of the 
 air so that sustentation may be maintained and headway 
 made. One second the bird is bending its wings, alter- 
 ing the angle of incidence ; the next it is lifting or de- 
 pressing one wing at a time. Still again it will extend 
 one wing tip in advance of the other, or be spreading or 
 folding, lowering or raising its tail. 
 
 All these motions have a meaning, a purpose. They 
 assist the bird in preserving its equilibrium. Without 
 them the bird would be just as helpless in the air as a 
 human being and could not remain afloat. 
 
 When the wind is still, or comparatively so, a bird, 
 having secured the desired altitude by flight at an angle, 
 may sail or soar with no wing action beyond an occa- 
 sional stroke when it desires to advance. But, in a 
 gusty, uncertain wind it must use its wings or alight 
 somewhere. 
 
 Trying to Imitate the Bird. 
 
 Writing in Fly, Mr. W r illiam E. White says: 
 "The bird's flight suggests a number of ways in which 
 the equilibrium of a mechanical bird may be controlled. 
 
CONSTRUCTION AND OPERATION 
 
 137 
 
 Each of these methods of control may be effected by 
 several different forms of mechanism. 
 
 "Placing the two wings of an aeroplane at an angle of 
 three to five degrees to each other is perhaps the oldest 
 way of securing lateral balance. This way readily oc- 
 curs to anyone who watches a sea gull soaring. The 
 theory of the dihedral angle is that when one wing is 
 lifted by a gust of wind, the air is spilled from under it ; 
 while the other wing, being correspondingly depressed, 
 presents a greater resistance to the gust and is lifted 
 
 Front Elevation of Multiplane Glider. 
 
 restoring the balance. A fixed angle of three to five de- 
 grees, however, will only be sufficient for very light puffs 
 of wind and to mount the wings so that the whole wing 
 may be moved to change the dihedral angle presents 
 mechanical difficulties which would be better avoided. 
 
 "The objection of mechanical impracticability applies 
 to any plan to preserve the balance by shifting weight 
 or ballast. The center of gravity should be lower than 
 the center of the supporting surfaces, but cannot be 
 made much lower. It is a common mistake to assume 
 that complete stability will be secured by hanging the 
 center of gravity very low on the principle of the para- 
 chute. An aeroplane depends upon rapid horizontal mo- 
 
138 FLYING MACHINES: 
 
 tion for its support, and if the center of gravity be far 
 below, the center of support, every change of speed or 
 wind pressure will cause the machine to turn about its 
 center of gravity, pitching forward and backward dan- 
 gerously. 
 
 Preserving Longitudinal Balance. 
 
 "The birds maintain longitudinal, or fore and aft bal- 
 ance, by elevating or depressing their tails. Whether 
 this action is secured in an aeroplane by means of a 
 horizontal rudder placed in the rear, or by deflecting 
 planes placed in front of the main planes, the principle 
 is evidently the same. A horizontal rudder placed well 
 to the rear as in the Antoinette, Bleriot or Santos-Du- 
 mont monoplanes, will be very much safer and steadier 
 than the deflecting planes in front, as in the Wright or 
 Curtiss biplanes, but not so sensitive or prompt in action. 
 
 "The natural fore and aft stability is very much 
 strengthened by placing the load well forward. The 
 center of gravity near the front and a tail or rudder 
 streaming to the rear secures stability as an arrow is 
 balanced by the head and feathering. The adoption of 
 this principle makes it almost impossible for the aero- 
 plane to turn over. 
 
 The Matter of Lateral Balance. 
 
 "All successful aeroplanes thus far have maintained 
 lateral balance by the principle of changing the angle 
 of incidence of the wings. 
 
 "Other ways of maintaining the lateral balance, sug- 
 gested by observation of the flight of birds are extend- 
 ing the wing tips and spilling the air through the pin- 
 ions ; or, what is the same thing, varying the area of the 
 wings at their extremities. 
 
 "Extending the wing tips seems to be a simple and 
 effective solution of the problem. The tips may be made 
 
CONSTRUCTION AND OPERATION 
 
 139 
 
 to swing outward upon a vertical axis placed at the front 
 edge of the main planes; or they may be hinged to the 
 ends of the main plane so as to be elevated or depressed 
 through suitable connections by the aviator ; or they may 
 be supported from a horizontal axis parallel with the 
 ends of the main planes so that they may swing out- 
 ward, the aviator controlling both tips through one lever 
 so that as one tip is extended the other is retracted. 
 
 Side Elevation of Multiplane Glider. 
 
 "The elastic wing pinions of a bird bend easily before 
 the wind, permitting the gusts to glance off, but pre- 
 senting always an even and efficient curvature to the 
 steady currents of the air." 
 
 High Winds Threaten Stability. 
 
 To ensure perfect stability, without control, either hu- 
 man or automatic, it is asserted that the aeroplane must 
 move faster than the wind is blowing. So long as the 
 wind is blowing at the rate of 30 miles an hour, and the 
 machine is traveling 40 or more, there will be little trou- 
 ble as regards equilibrium so far as wind disturbance 
 
140 FLYING MACHINES: 
 
 goes, provided the wind blows evenly and does not come 
 in gusts or eddying currents. But when conditions are 
 reversed when the machine travels only 30 miles an 
 hour and the wind blows at the rate of 50, look out for 
 loss of equilibrium. 
 
 One of the main reasons for this is that high winds 
 are rarely steady; they seldom blow for any length of 
 time at the same speed. They are usually "gusty," the 
 gusts being a momentary movement at a higher speed. 
 Tornadic gusts are also formed by the meeting of two 
 opposing currents, causing a whirling motion, which 
 makes stability uncertain. Besides, it is not unusual 
 for wind of high speed to suddenly change its direction 
 without warning. 
 
 Trouble With Vertical Columns. 
 
 Vertical currents columns of ascending air are fre- 
 quently encountered in unexpected places and have more 
 or less tendency, according to their strength, to make 
 it difficult to keep the machine within a reasonable dis- 
 tance from the ground. 
 
 These vertical currents are most generally noticeable 
 in the vicinity of steep cliffs, or deep ravines. In such 
 instances they are usually of considerable strength, be- 
 ing caused by the deflection of strong winds blowing 
 against the face of the cliffs. This deflection exerts a 
 back pressure which is felt quite a distance away from 
 the point of origin, so that the vertical current exerts an 
 influence in forcing the machine upward long before the 
 cliff is reached. 
 
CHAPTER XV. 
 
 THE ELEMENT OF DANGER. 
 
 That there is an element of danger in aviation is un- 
 deniable, but it is nowhere so great as the public 
 imagines. Men are killed and injured in the operation 
 of flying machines just as they are killed and injured in 
 the operation of railways. Considering the character of 
 aviation the percentage of casualties is surprisingly 
 small. 
 
 This is because the results following a collapse in the 
 air are very much different from what might be imagined. 
 Instead of dropping to the ground like a bullet an aero- 
 plane, under ordinary conditions will, when anything 
 goes wrong, sail gently downward like a parachute, par- 
 ticularly if the operator is cool-headed and nervy enough 
 to so manipulate the apparatus as to preserve its equili- 
 brium and keep the machine on an even keel. 
 
 Two Fields of Safety. 
 
 At least one prominent aviator has declared that there 
 are two fields of safety one close to the ground, and 
 the other well up in the air. In the first-named the fall 
 will be a slight one with little chance of the operator 
 being seriously hurt. From the field of high altitude the 
 the descent will be gradual, as a rule, the planes of the 
 machine serving to break the force of the fall. With a 
 cool-headed operator in control the aeroplane may be 
 even guided at an angle (about i to 8) in its descent so 
 
 141 
 
142 FLYING MACHINES: 
 
 as to touch the ground with a gliding motion and with 
 a minimum of impact. 
 
 Such an experience, of course, is far from pleasant, 
 but it is by no means so dangerous as might appear. 
 There is more real danger in falling from an elevation 
 of 75 or 100 feet than there is from 1,000 feet, as in the 
 former case there is no chance for the machine to serve as 
 a parachute its contact with the ground conies too 
 quickly. 
 
 Lesson in Recent Accidents. 
 
 Among the more recent fatalities in aviation are the 
 deaths of Antonio Fernandez and Leon Delagrange. True 
 former was thrown to the ground by a sudden stoppage 
 of his motor, the entire machine seeming to collapse. 
 It is evident there were radical defects, not only in the 
 motor, but in the aeroplane framework as well. At the 
 time of the stoppage it is estimated that Fernandez was 
 up about 1,500 feet, but the machine got no opportunity 
 to exert a parachute effect, as it broke up immediately. 
 This would indicate a fatal weakness in the structure 
 which, under proper testing, could probably have been 
 detected before it was used in flight. 
 
 It is hard to say it, but Delagrange appears to have 
 been culpable to great degree in overloading his ma- 
 chine with a motor equipment much heavier than it was 
 designed to sustain. He was 65 feet up in the air when 
 the collapse occurred, resulting in his death. As in the 
 case of Fernandez common-sense precaution would 
 doubtless have prevented the fatality. 
 
 Aviation Not Extra Hazardous. 
 
 All told there have been, up to the time of this writing 
 (April, 1910), just five fatalities in the history of power- 
 driven aviation. This is surprisingly low when the na- 
 ture of the experiments, and the fact that most of the 
 
CONSTRUCTION AND OPERATION 143 
 
 operators were far from having extended experience, is 
 taken into consideration. Men like the Wrights, Curtiss, 
 Bleriot, Farman, Paulhan and others, are now experts, 
 but there was a time, and it was not long ago, when they 
 were unskilled. That they, with numerous others less 
 widely known, should have come safely through their 
 many experiments would seem to disprove the prevailing 
 idea that aviation is an extra hazardous pursuit. 
 
 In the hands of careful, quick-witted, nervy men the 
 sailing of an airship should be no more hazardous than 
 the sailing of a yacht. A vessel captain with common 
 sense will not go to sea in a storm, or navigate a weak, 
 unseaworthy craft. Neither should an aviator attempt 
 to sail when the wind is high and gusty, nor with a ma- 
 chine which has not been thoroughly tested and found to 
 be strong and safe. 
 
 Safer Than Railroading. 
 
 Statistics show that some 12,000 people are killed and 
 72,000 injured every year on the railroads of the United 
 States. Come to think it over it is small wonder that 
 the list of fatalities is so large. Trains are run at high 
 speeds, dashing over crossings at which collisions are 
 liable to occur, and over bridges which often collapse 
 or are swept away by floods. Still, while the number of 
 casualties is large, the actual percentage is small con- 
 sidering the immense number of people involved. 
 
 It is so in aviation. The number of casualties is re- 
 markably small in comparison with the number of flights 
 made. In the hands of competent men the sailing of an 
 airship should be, and is, freer from risk of accident than 
 the running of a railway train. There are no rails to 
 spread or break, no bridges to collapse, no crossings at 
 which collisions may occur, no chance for some sleepy 
 or overworked employee to misunderstand the dis- 
 patcher's orders and cause a wreck. 
 
144 FLYING MACHINES: 
 
 Two Main Causes of Trouble. 
 
 The two main causes of trouble in an airship leading 
 to disaster may be attributed to the stoppage of the 
 motor, and the aviator becoming rattled so that he loses 
 control of his machine. Modern ingenuity is fast devel- 
 oping motors that almost daily become more and more 
 reliable, and experience is making aviators more and 
 more self-confident in their ability to act wisely and 
 promptly in cases of emergency. Besides this a satis- 
 factory system of automatic control is in a fair way 
 of being perfected. 
 
 Occasionally even the most experienced and competent 
 of men in all callings become careless and by foolish 
 action invite disaster. This is true of aviators the same 
 as it is of railroaders, men who work in dynamite mills, 
 etc. But in nearly every instance the responsibility rests 
 with the individual ; not with the system. There are 
 some men unfitted by nature for aviation, just as there 
 are others unfitted to be railway engineers. 
 
CHAPTER XVI. 
 
 RADICAL CHANGES BEING MADE. 
 
 Changes, many of them extremely radical in their na- 
 ture, are continually being made by prominent aviators, 
 and particularly those who have won the greatest amount 
 of success. Wonderful as the results have been few of 
 
 Sectional View of New Wright Machine. 
 
 the aviators are really satisfied. Their successes have 
 merely spurred them on to new endeavors, the ultimate 
 end being the development of an absolutely perfect air- 
 craft. 
 
 Among the men who have been thus experimenting 
 are the Wright Brothers, who last year (1909) brought 
 
 145 
 
146 FLYING MACHINES: 
 
 out a craft totally different as regards proportions and 
 weight from the one used the preceding year. One 
 marked result was a gain of about 3^ miles an hour in 
 speed. 
 
 Dimensions of 1908 Machine. 
 
 The 1908 model aeroplane was 40 by 29 feet over all. 
 The carrying surfaces, that is, the two aerocurves, were 
 40 by 6 feet, having a parabolical curve of one in twelve. 
 With about 70 square feet of surface in the rudders, the 
 total surface given was about 550 square feet. The 
 engine, which is the invention of the Wright brothers, 
 weighed, approximately, 200 pounds, and gave about 25 
 horsepower at 1,400 revolutions per minute. The total 
 weight of the aeroplane, exclusive of passenger, but in- 
 clusive of engine, was about 1,150 pounds. This result 
 showed a lift of a fraction over 2j4 pounds to the square 
 foot of carrying surface. The speed desired was 40 
 miles an hour, but the machine was found to make only 
 a scant 39 miles an hour. The upright struts were 
 about %-inch thick, the skids, 2,y 2 by i]/\ inches thick. 
 
 Dimensions of 1909 Machine. 
 
 The 1909 aeroplane was built primarily for greater 
 speed, and relatively heavier ; to be less at the mercy 
 of the wind. This result was obtained as follows: The 
 aerocurves, or carrying surfaces, were reduced in dimen- 
 sions from 40 by 6 feet to 36 by 5^2 feet, the curve re- 
 maining the same, one in twelve. The upright struts 
 were cut from seven-eighths inch to five-eighths inch, and 
 the skids from two and one-half by one and one-quarter 
 to two and one-quarter by one and three-eighths inches. 
 This result shows that there were some 81 square feet 
 of carrying surface missing over that of last year's 
 model., and some 25 pounds loss of weight. Relatively, 
 
CONSTRUCTION AND OPERATION 
 
 147 
 
 though, the 1909 model aeroplane, while actually 25 
 pounds lighter, is really some 150 pounds heavier in the 
 air than the 1908 model, owing to the lesser square 
 feet of carrying surface. 
 
 Some of the Results Obtained. 
 
 Reducing the carrying surfaces from 6 to 5^2 feet 
 
 Outline of Santos-Dumont's Monoplane as Seen From Above. 
 
 gave two results first, less carrying capacity ; and, sec- 
 ond, less head-on resistance, owing to the fact that the 
 extent of the parabolic curve in the carrying surfaces 
 was shortened. The "head-on" resistance is the retard- 
 ance the aeroplane meets in passing through the air, 
 and is counted in square feet. In the 1908 model the 
 curve being one in twelve and 6 feet deep, gave 6 inches 
 of head-on resistance. The plane being 40 feet spread, 
 
148 FLYING MACHINES: 
 
 gave 6 inches by 40 feet, or 20 square feet of head-on 
 resistance. Increasing this figure by a like amount for 
 each plane, and adding approximately 10 square feet for 
 struts, skids and wiring, we have a total of approximate- 
 ly, 50 square feet of surface for "head-on" resistance. 
 
 In the 1909 aeroplane, shortening the curve 6 inches 
 at the parabolic end of the curve took off i inch of 
 head-on resistance. Shortening the spread of the planes 
 took off between 3 and 4 square feet of head-on resist- 
 ance. Add to this the total of 7 square feet, less curve 
 surface and about I square foot, less wire and wood- 
 work resistance, and we have a grand total of, approxi- 
 mately, 12 square feet of less "head-on" resistance over 
 the 1908 model. 
 
 Changes in Engine Action. 
 
 The engine used in 1909 was the same one used in 
 1908, though some minor changes were made as im- 
 provements ; for instance, a make and break spark was 
 used, and a nine-tooth, instead of a ten-tooth magneto 
 gear-wheel was used. This increased the engine revolu- 
 tions per minute from 1,200 to 1,400, and the propeller 
 revolutions per minute from 350 to 371, giving a pro- 
 peller thrust of, approximately, 170 foot pounds instead 
 of 153, as was had last year. 
 
 More Speed and Same Capacity. 
 
 One unsatisfactory feature of the 1909 model over 
 that of 1908, apparently, was the lack of inherent lateral 
 stability. This was caused by the lesser surface and 
 lesser extent of curvatures at the portions of the aero- 
 plane which were warped. This defect did not show so 
 plainly after Mr. Orville Wright had become fully pro- 
 ficient in the handling of the new machine, and with 
 skillful management, the 1909 model aeroplane will be 
 
CONSTRUCTION AND OPERATION 
 
 149 
 
 just as safe and secure as the other though it will take 
 a little more practice to get that same degree of skill. 
 
 To sum up : The aeroplane used in 1909 was 25 
 pounds lighter, but really about 150 pounds heavier in 
 
 Side View of Santos-Dumont's Monoplane. 
 
 the air, had less head-on resistance, and greater pro- 
 peller thrust. The speed was increased from about 39 
 miles per hour to 42^ miles per hour. The lifting ca- 
 pacity remained about the same, about 450 pounds ca- 
 pacity passenger-weight, with the 1908 machine. In this 
 
 Front View of Santos-tDumont Monoplane. 
 
 respect, the loss of carrying surface was compensated for 
 by the increased speed. 
 
 During the first few flights it was plainly demon- 
 strated that it would need the highest skill to properly 
 handle the aeroplane, as first one end and then the other 
 would dip and strike the ground, and either tear the can- 
 vas or slew the aeroplane around and break a skid. 
 
150 FLYING MACHINES: 
 
 Wrights Adopt Wheeled Gears. 
 
 In still another important respect the Wrights, so far 
 as the output of one of their companies goes, have made 
 a radical change. All the aeroplanes turned out by the 
 Deutsch Wright Gesellschaft, according to the German 
 publication, Automobil-Welt, will hereafter be equipped 
 with wheeled running gears and tails. The plan of this 
 new machine is shown in the illustration on page 145. 
 The wheels are three in number, and are attached one 
 to each of the two skids, just under the front edge of 
 the planes, and one forward of these, attached to a cross- 
 member. It is asserted that with these wheels the 
 teaching of purchasers to operate the machines is much 
 simplified, as the beginners can make short flights on 
 their own account without using the starting derrick. 
 
 This is a big concession for the Wrights to make, as 
 they have hitherto adhered stoutly to the skid gear. 
 While it is true they do not control the German com- 
 pany producing their aeroplanes, yet the nature of their 
 connection with the enterprise is such that it may be 
 taken for granted no radical changes in construction 
 would be made without their approval and consent. 
 
 Only Three Dangerous Rivals. 
 
 Official trials with the 1909 model smashed many rec- 
 ords and leave the Wright brothers with only three dan- 
 gerous rivals in the field, and with basic patents which 
 cover the curve, warp and wing-tip devices found on 
 all the other makes of aeroplanes. These three rivals 
 are the Curtiss and Voisin biplane type and the Bleriot 
 monoplane pattern. 
 
 The Bleriot monoplane is probably the most danger- 
 ous rival, as this make of machine has a record of 54 
 miles per hour, has crossed the English channel ^nd 
 has lifted two passengers besides the operator. The lat- 
 
CONSTRUCTION AND OPERATION 
 
 151 
 
152 FLYING MACHINES: 
 
 est type of this machine only weighs 771.61 pounds com- 
 plete, without passengers, and will lift a total passenger 
 weight of 462.97 pounds, which is a lift of 5.21 pounds 
 to the square foot. This is a bettei result than those 
 published by the Wright brothers, the best noted being 
 4.25 pounds per square foot. 
 
 Other Aviators at Work. 
 
 The Wrights, however, are not alone in their efforts 
 to promote the efficiency of the flying machine. Other 
 competent inventive aviators, notably Curtiss, Voisin, 
 Bleriot and Farman, are close after them. The Wrights, 
 as stated, have a marked advantage in the possession of 
 patents covering surface plane devices which have thus 
 far been found indispensable in flying machine construc- 
 tion. Numerous law suits growing out of alleged in- 
 fringements of these patents have been started, and 
 others are threatened. What effect these actions will 
 have in deterring aviators in general from proceeding 
 with their experiments remains to be seen. 
 
 In the meantime the four men named Curtiss, Voisin, 
 Bleriot and Farman are going ahead regardless of con- 
 sequences, and the inventive genius of each is so strong 
 that it is reasonable to expect some remarkable develop- 
 ments in the near future. 
 
 Smallest of Flying Machines. 
 
 To Santos Dumont must be given the credit of pro- 
 ducing the smallest practical flying machine yet con- 
 structed. True, he has done nothing remarkable with it 
 in the line of speed, but he has demonstrated the fact 
 that a large supporting surface is not an essential feature. 
 
 This machine is named "La Demoiselle." It is a mono- 
 plane of the dihedral type, with a main plane on each 
 
CONSTRUCTION AND OPERATION 153 
 
 side of the center. These main planes are of 18 foot 
 spread, and nearly 6^2 feet in depth, giving approximately 
 115 feet of surface area. The total weight is 242 pounds, 
 which is 358 pounds less than any other machine which 
 has been successfully used. The total depth from front 
 to rear is 26 feet. 
 
 Position of Motor on Brauner-Smith Machine. 
 
 The framework is of bamboo, strengthened and held 
 taut with wire guys. 
 
 Have One Rule in Mind. 
 
 In this struggle for mastery in flying machine effici- 
 ency all the contestants keep one rule in mind, and this 
 is: 
 
 "The carrying capacity of an aeroplane is governed 
 by the peripheral curve of its carrying surfaces, plus the 
 speed; and the speed is governed by the thrust of the 
 propellers, less the 'head-on' resistance." 
 
154 FLYING MACHINES: 
 
 Their ideas as to the proper means of approaching 
 the proposition may, and undoubtedly are, at variance, 
 but the one rule in solving the problem of obtaining the 
 greatest carrying capacity combined with the greatest 
 speed, obtains in all instances. 
 
CHAPTER XVII. 
 
 SOME OF THE NEW DESIGNS. 
 
 Spurred on by the success attained by the more expe- 
 rienced and better known aviators numerous inventors 
 of lesser fame are almost daily producing practical fly- 
 ing machines varying radically in construction from 
 those now in general use. 
 
 One of these comparatively new designs is the Van 
 
 How the New Van Anden Machine Looks. 
 
 Anden biplane, made by Frank Van Anden of Islip, 
 Long Island, a member of the New York Aeronautic 
 Society. While his machine is wholly experimental, 
 many successful short flights were made with it last fall 
 (1909). One flight, made October iQth, 1909, is of par- 
 
 155 
 
156 FLYING MACHINES: 
 
 ticular interest as showing the practicability of an auto- 
 matic stabilizing device installed by the inventor. The 
 machine was caught in a sudden severe gust of wind 
 and keeled over, but almost immediately righted itself, 
 thus demonstrating in a most satisfactory manner the 
 value of one new attachment. 
 
 Features of Van Anden Model. 
 
 In size the surfaces of the main biplane are 26 feet 
 in spread, and 4 feet in depth from front to rear. The 
 upper and lower planes are 4 feet apart. Silkolene 
 coated with varnish is used for the coverings. Ribs 
 (spruce) are curved one inch to the foot, the deepest 
 part of the curve (4 inches) being one foot back from the 
 front edge of the horizontal beam. Struts (also of 
 spruce, as is all the framework) are elliptical in shape. 
 The main beams are in three sections, nearly half round 
 in form, and joined by metal sleeves. 
 
 There is a tw^o-surface horizontal rudder, 2x2x4 f eet > 
 in front. This is pivoted at its lateral center 8 feet from 
 the front edge of the main planes. In the rear is an- 
 other two-surface horizontal rudder 2x2x2^ feet, pivoted 
 in the same manner as the front one, 15 feet from the 
 rear edges of the main planes. 
 
 Hinged to the rear central strut of the rear rudder 
 is a vertical rudder 2 feet high by 3 feet in length. 
 
 The Method of Control. 
 
 In the operation of these rudders both front and rear 
 and the elevation and depression of the main planes, 
 the Curtiss system is employed. Pushing the steering- 
 wheel post outward depresses the front edges of the 
 planes, and brings the machine downward ; pulling the 
 steering-wheel post inward elevates the front edges of 
 the planes and causes the machine to ascend. 
 
CONSTRUCTION AND OPERATION 
 
 157 
 
 Turning the steering wheel itself to the right swings 
 the tail rudder to the left, and the machine, obeying this 
 like a boat, turns in the same direction as the wheel 
 is turned. By like cause turning the wheel to the left 
 turns the machine to the left. 
 
 Walden's Automatic Stability System. 
 
 The four tubes represent the 4-cylinder motor; A engine 
 shaft; B auxiliary shaft; D, D, D ball bearings; E, E separat- 
 ing rods; F and G methods of attaching propeller. 
 
 Automatic Control of Wings. 
 
 There are two wing tips, each of 6 feet spread (length) 
 and 2 feet from front to rear. These are hinged half 
 way between the main surfaces to the two outermost 
 rear struts. Cables run from these to an automatic 
 device working with power from the engine, which an- 
 
158 FLYING MACHINES: 
 
 tomatically operates the tips with the tilting of the 
 machine. Normally the wing tips are held horizontal 
 by stiff springs introduced in the cables outside of the 
 device. 
 
 It was the successful working of this device which 
 righted the Van Anden craft when it was overturned in 
 the squall of October iQth, 1909. Previous to that 
 occurrence Mr. Van Anden had looked upon the device 
 as purely experimental, and had admitted that he had 
 grave uncertainty as to how it would operate in time of 
 emergency. He is now quoted as being thoroughly sat- 
 isfied with its practicability. It is this automatic device 
 which gives the Van Anden machine at least one dis- 
 tinctively new feature. 
 
 While on this subject it will not be amiss to add that 
 Mr. Curtiss does not look kindly on automatic control. 
 "I would rather trust to my own action than that of n 
 machine," he says. This is undoubtedly good logic so 
 far as Mr. Curtiss is concerned, but all aviators are not 
 so cool-headed and resourceful. 
 
 Motive Power of Van Anden. 
 
 A 5ohorsepower "H-F" water cooled motor drives a 
 laminated wood propeller 6 feet in diameter, with a 17 
 degree pitch at the extremities, increasing toward the 
 hub. The rear end of the motor is about 6 inches back 
 from the rear transverse beam and the engine shaft is 
 in a direct line with the axes of the two horizontal rud- 
 ders. An R. I. V. ball bearing carries the shaft at this 
 point. Flying, the motor turns at about 800 revolutions 
 per minute, delivering 180 pounds pull. A test of the 
 motor running at 1,200 showed a pull of 250 pounds on 
 the scales. 
 
 Still Another New Aeroplane. 
 
 Another new aeroplane is that produced by A. M. 
 
CONSTRUCTION AND OPERATION 
 
 159 
 
160 FLYING MACHINES: 
 
 Herring (an old-timer) and W. S. Burgess, under the 
 name of the Herring-Burgess. This is also equipped 
 with an automatic stability device for maintaining the 
 balance transversely. The curvature of the planes is 
 also laid out on new lines. That this new plan is ef- 
 fective is evidenced by the fact that the machine has 
 been elevated to an altitude of 40 feet by using one-half 
 the power of the 3O-horsepower motor. 
 
 The system of rudder and elevation control is very 
 simple. The aviator sits in front of the lower plane, 
 and extending his arms, grasps two supports which ex- 
 tend down diagonally in front. On the under side of 
 these supports just beneath his fingers are the controls 
 which operate the vertical rudder, in the rear. Thus, if 
 he wishes to turn to the right, he presses the control 
 under the fingers of his right hand; if to the left, that 
 under the fingers of his left hand. The elevating rud- 
 der is operated by the aviator's right foot, the control 
 being placed on a foot-rest. 
 
 Motor Is Extremely Light. 
 
 Not the least notable feature of the craft is its motor. 
 Although developing, under load, 3o-horsepower, or that 
 of an ordinary automobile, it weighs, complete, hardly 
 TOO pounds. Having occasion to move it a little dis- 
 tance for inspection, Mr. Burgess picked it up and walked 
 off with it cylinders, pistons, crankcase and all, even 
 the magneto, being attached. There are not many 30- 
 horsepower engines which can be so handled. Every- 
 thing about it is reduced to its lowest terms of simplic- 
 ity, and hence, of weight. A single camshaft operates 
 not only all of the inlet and exhaust valves, but the mag- 
 neto and gear water pump, as well. The motor is placed 
 directly behind the operator, and the propeller is direct- 
 ly mounted on the crankshaft. 
 
CONSTRUCTION AND OPERATION 
 
 161 
 
 This weight of less than 100 pounds, it must be re- 
 membered, is not for the motor alone ; it includes the 
 entire power plant equipment. 
 
 The "thrust" of the propeller is also extraordinary, 
 being between 250 and 260 pounds. The force of the 
 wind displacement is strong enough to knock down a 
 good-sized boy as one youngster ascertained when he 
 got behind the propeller as it was being tested. He 
 was not only knocked down but driven for some dis- 
 tance away from the machine. The propeller has four 
 blades which are but little wider than a lath. 
 
 
 
 
 Aeroplane Constructed by U. of P. Students. 
 
 Machine Built by Students. 
 
 Students at the University of Pennsylvania, headed by 
 Laurence J. Lesh, a protege of Octave Chanute, have 
 constructed a practical aeroplane of ordinary maximum 
 size, in which is incorporated many new ideas. The 
 
162 FLYING MACHINES: 
 
 most unique of these is to be found in the steering gear, 
 and the provision made for the accommodation of a 
 pupil while taking lessons under an experienced aviator. 
 Immediately back of the aviator is an extra seat and 
 an extra steering wheel which works in tandem style 
 with the front wheel. By this arrangement a beginner 
 may be easily and quickly taught to have perfect con- 
 trol of the machine. These tandem wheels are also 
 handy for passengers who may wish to operate the car 
 independently of one another, it being understood, of 
 course, that there will be no conflict of action. 
 
 Frame Size and Engine Power. 
 
 The frame has 36 feet spread and measures 35 feet 
 from the front edge to the end of the tail in the rear. It 
 is equipped with two rear propellers operated by a Ram- 
 sey 8-cylinder motor of 50 horsepower, placed horizon- 
 tally across the lower plane, with the crank shaft run- 
 ning clear through the engine. 
 
 The "Pennsylvania I" is the first two-propeller biplane 
 chainless car, this scheme having been adopted in order 
 to avoid the crossing of chains. The lateral control is 
 by a new invention by Octave Chanute and Laurence J. 
 Lesh, for which Lesh is now applying for a patent. The 
 device was worked out before the Wright brothers' suit 
 was begun, and is said to be superior to the Wright 
 warping or the Curtiss ailerons. The landing device is 
 also new in design. This aeroplane will weigh about 
 1,500 pounds, and will carry fuel for a flight of 150 miles, 
 and it is expected to attain a speed of at least 45 miles 
 an hour. 
 
 There are others, lots of them, too numerous in fact 
 to admit of mention in a book of this size. 
 
CHAPTER XVIII. 
 
 DEMAND FOR FLYING MACHINES. 
 
 ' As a commercial proposition the manufacture and sale 
 of motor-equipped aeroplanes is making much more 
 rapid advance than at first obtained in the similar 
 handling of the automobile. Great, and even phenom- 
 enal, as was the commercial development of the motor 
 car, that of the flying machine is even greater. This is 
 a startling statement, but it is fully warranted by the 
 facts. 
 
 It is barely more than a year ago (1909) that atten- 
 tion was seriously attracted to the motor-equipped aero- 
 plane as a vehicle possible of manipulation by others 
 than professional aviators. Up to that time such actual 
 flights as were made were almost exclusively with the 
 sole purpose of demonstrating the practicability of the 
 machine, and the merits of the ideas as to shape, engine 
 power, etc., of the various producers. 
 
 Results of Bleriot's Daring. 
 
 It was not until Bleriot flew across the straits of 
 Dover on July 25th, 1909, that the general public awoke 
 to a full realization of the fact that it was possible for 
 others than professional aviators to indulge in avia- 
 tion. Bleriot's feat was accepted as proof that at last an 
 absolutely new means of sport, pleasure and research, 
 had been practically developed, and was within the 
 
 163 
 
164 FLYING MACHINES: 
 
 reach of all who had the inclination, nerve and finan- 
 cial means to adopt it. 
 
 From this event may be dated the birth of the mod- 
 ern riving machine into the world of business. The auto- 
 mobile was taken up by the general public from the 
 very start because it was a proposition comparatively 
 easy of demonstration. There was nothing mysterious 
 or uncanny in the fact that a wheeled vehicle could be 
 propelled on solid, substantial roads by means of engine 
 power. And yet it took (comparatively speaking) a long 
 time to really popularize the motor car. 
 
 Wonderful Results in a Year. 
 
 Men of large financial means engaged in the manufac- 
 ture of automobiles, and expended fortunes in attract- 
 ing public attention to them through the medium of 
 advertisements, speed and road contests, etc. By these 
 means a mammoth business has been built up, but bring- 
 ing this business to its present proportions required 
 years of patient industry and indomitable pluck. 
 
 At this writing, less than a year from the day when 
 Bleriot crossed the channel, the actual sales of flying 
 machines outnumber the actual sales of automobiles in 
 the first year of their commercial development. This, 
 may appear incredible, but it is a fact as statistics will 
 show. 
 
 In this connection we should take into consideration 
 the fact that up to a year ago there was no serious in- 
 tention of putting flying machines on the market ; no 
 preparations had been made to produce them on a com- 
 mercial scale ; no money had been expended in adver- 
 tisements with a view to selling them. 
 
 Some of the Actual Results. 
 
 Today flying machines are being produced on a com- 
 mercial basis, and there is a big demand for them. The 
 
CONSTRUCTION AND OPERATION 165 
 
 people making them are overcrowded with orders. Some 
 of the producers are already making arrangements to 
 enlarge their plants and advertise their product for sale 
 the same as is being done with automobiles, while a 
 number of flying machine motor makers are already 
 promoting the sale of their wares in this way. 
 
 Here are a few actual figures of flying machine sales 
 made by the more prominent producers since July 25th, 
 1909: 
 
 Santos Dumont, 90 machines : Bleriot, 200 ; Farman, 
 130; Clemenceau-Wright, 80; Voisin, 100; Antoinette, 
 TOO. Many of these orders have been filled by delivery 
 of the machines, and in others the construction work 
 is under way. 
 
 The foregoing are all of foreign make. In this coun- 
 try Curtiss and the Wrights are engaged in similar 
 work, but no actual figures of their output are obtain- 
 able. 
 
 Larger Plants Are Necessary. 
 
 And this situation exists despite the fact that none of 
 the producers are really equipped with adequate plants 
 for turning out their machines on a modern, business- 
 like basis. The demand was so sudden and unexpected 
 that it found them poorly prepared to meet it. This, 
 however, is now being remedied by the erection of spe- 
 cial plants, the enlargement of others, and the intro- 
 duction of new machinery and other labor-saving con- 
 veniences. 
 
 Companies, with large capitalization, to engage in the 
 exclusive production of airships are being organized in 
 many parts of the world. One notable instance of this 
 nature is worth quoting as illustrative of the manner 
 in which the production of flying machines is being com- 
 mercialized. This is the formation at Frankfort, Ger- 
 many, of the Flugmaschine Wright, G. m. b. H., with 
 
166 FLYING MACHINES: 
 
 a capital of $119,000, the Krupps, of Essen, being inter- 
 ested. 
 
 Prices at Which Machines Sell. 
 
 This wonderful demand from the public has come not- 
 withstanding the fact that the machines, owing to lack 
 of facilities for wholesale production, are far from be- 
 ing cheap. Such definite quotations as are made are 
 on the following basis: 
 
 Santos Dumont List price $1,000, but owing to the 
 rush of orders agents are readily getting from $1,300 to 
 $1,500. This is the smallest machine made. 
 
 Bleriot List price $2,500. This is for the cross- 
 channel type, with Anzani motor. 
 
 Antoinette List price from $4,000 to $5,000, accord- 
 ing to size. 
 
 Wright List price $5,600. 
 
 Curtiss List price $5,000. 
 
 There is, however, no stability in prices as purchasers 
 are almost invariably ready to pay a considerable pre- 
 mium to facilitate delivery. 
 
 The motor is the most expensive part of the flying 
 machine. Motor prices range from $500 to $2,000, this 
 latter amount being asked for the Curtiss engine. 
 
 Systematic Instruction of Amateurs. 
 
 In addition to the production of flying machines many 
 of the experienced aviators are making a business of 
 the instruction of amateurs. Curtiss and the Wrights 
 in this country have a number of pupils, as have also 
 the prominent foreigners. Schools of instruction are 
 being opened in various parts of the world, not alone as 
 private money-making ventures, but in connection with 
 public educational institutions. One of these latter is 
 to be found at the University of Barcelona, Spain. 
 
 The flying machine agent, the man who handles the 
 
CONSTRUCTION AND OPERATION 
 
 167 
 
168 FLYING MACHINES: 
 
 machines on a commission, has also become a known 
 quantity, and will soon be as numerous as his brother 
 of the automobile. The sign "J onn Bird, agent for Skim- 
 mer's Flying Machine," is no longer a curiosity. 
 
 Yes, the Airship Is Here. 
 
 From all of which we may well infer that the flying 
 machine in practical form has arrived, and that it is 
 here to stay. It is no exaggeration to say that the time 
 is close at hand when people will keep flying machines 
 just as they now keep automobiles, and that pleasure 
 jaunts will be fully as numerous and popular. With 
 the important item of practicability fully demonstrated, 
 "Come, take a trip in my airship," will have more real 
 significance than now attaches to the vapid warblings 
 of the vaudeville vocalist. 
 
 As a further evidence that the airship is really here, 
 and that its presence is recognized in a business way, 
 the action of life and accident insurance companies is 
 interesting. Some of them are reconstructing their poli- 
 cies so as to include a special waiver of insurance by 
 aviators. Anything which compels these great corpora- 
 tions to modify their policies cannot be looked upon as 
 a mere curiosity or toy. 
 
 It is some consolation to know that the movement in 
 this direction is not thus far widespread. Moreover it 
 is more than probable that the competition for busi- 
 ness will eventually induce the companies to act more 
 liberally toward aviators, especially as the art of avia- 
 tion advances. 
 
CHAPTER XIX. 
 
 LAW OF THE AIRSHIP. 
 
 Successful aviation has evoked some peculiar things 
 in the way of legal action and interpretation of the law. 
 
 It is well understood that a man's property cannot 
 be used without his consent. This is an old established 
 principle in common law which holds good today. 
 
 The limits of a man's property lines, however, have 
 not been so well understood by laymen. According to 
 eminent legal authorities such as Blackstone, Littleton 
 and Coke, the "fathers of the law," the owner of realty 
 also holds title above and below the surface, and this 
 theory is generally accepted without question by the 
 courts. 
 
 Rights of Property Owners. 
 
 In other words the owner of realty also owns the sky 
 above it without limit as to distance. He can dig as 
 deep into his land, or go as high into the air as he de- 
 sires, provided he does not trespass upon or injure similar 
 rights of others. 
 
 The owner of realty may resist by force, all other 
 means having failed, any trespass upon, or invasion of 
 his property. Other people, for instance, may not enter 
 upon it, or over or under it, without his express per- 
 mission and consent. There is only one exception, and 
 this is in the case of public utility corporations such as 
 railways which, under the law of eminent domain, may 
 condemn a right of way across the property of an ob- 
 
 169 
 
170 FLYING MACHINES: 
 
 stinate owner who declines to accept a fair price for the 
 privilege. 
 
 Privilege Sharply Confined. 
 
 The law of eminent domain may be taken advantage 
 of only by corporations which are engaged in serving 
 the public. It is based upon the principle that the ad- 
 vancement and improvement of a community is of more 
 importance and carries with it more rights than the in- 
 terests of the individual owner. But even in cases where 
 the right of eminent domain is exercised there can be no 
 confiscation of the individual's property. 
 
 Exercising the right of eminent domain is merely ob- 
 taining by public purchase what is held to be essential 
 to the public good, and which cannot be secured by pri- 
 vate purchase. When eminent domain proceedings are 
 resorted to the court appoints appraisers who determine 
 upon the value of the property wanted, and this value 
 (in money) is paid to the owner. 
 
 How It Affects Aviation. 
 
 It should be kept in mind that this privilege of the 
 "right of eminent domain" is accorded only to corpora- 
 tions which are engaged in serving the public. Individ- 
 uals cannot take advantage of it. Thus far all aviation 
 has been conducted by individuals ; there are no flying 
 machine or airship corporations regularly engaged in the 
 transportation of passengers, mails or freight. 
 
 This leads up to the question "What would happen if 
 realty owners generally, or in any considerable numbers, 
 should prohibit the navigation of the air above their 
 holdings?" It is idle to say such a possibility is ridicu- 
 lous it is already an actuality in a few individual in- 
 stances. 
 
 One property owner in New Jersey, a justice of the 
 peace, maintains a large sign on the roof of his house 
 
CONSTRUCTION AND OPERATION 171 
 
 warning aviators that they must not trespass upon his 
 domain. That he is acting well within his rights in do- 
 ing this is conceded by legal authorities. 
 
 Hard to Catch Offenders. 
 
 But, suppose the alleged trespass is committed, what 
 is the property owner going to do about it? He must 
 first catch the trespasser and this would be a pretty hard 
 job. He certainly could not overtake him, unless he 
 kept a racing aeroplane for this special purpose. It 
 would be equally difficult to indentify the offender after 
 the offense had been committed, even if he were located, 
 as aeroplanes carry no license numbers. 
 
 Allowing that the offender should be caught the only 
 recourse of the realty owner is an action for damages. 
 He may prevent the commission of the offense by force 
 if necessary, but after it is committed he can only sue 
 for damages. And in doing this he would have a lot of 
 trouble. 
 
 Points to Be Proven. 
 
 One of the first things the plaintiff would be called 
 upon to prove would be the elevation of the machine. 
 If it were reasonably close to the ground there would, 
 of course, be grave risk of damage to fences, shrubbery, 
 and other property, and the court would be justified in 
 holding it to be a nuisance that should be suppressed. 
 
 If, on the other hand, the machine was well up in the 
 air, but going slowly, or hovering over the plaintiff's 
 property, the court might be inclined to rule that it 
 could not possibly be a nuisance, but right here the court 
 would be in serious embarrassment. By deciding that 
 it was not a nuisance he would virtually override the 
 law against invasion of a man's property without his 
 consent regardless of the nature of the invasion. By 
 the same decision he would also say in effect that, if one 
 
172 FLYING MACHINES: 
 
 flying machine could do this a dozen or more would 
 have equal right to do the same thing. While one ma- 
 chine hovering over a certain piece of property may be 
 no actual nuisance a dozen or more in the same position 
 could hardly be excused. 
 
 Difficult to Fix Damages. 
 
 Such a condition would tend to greatly increase the 
 risk of accident, either through collision, or by the care- 
 lessness of the aviators in dropping articles which might 
 cause damages to the people or property below. In 
 such a case it would undoubtedly be a nuisance, and 
 in addition to a fine, the offender would also be liable 
 for the damages. 
 
 Taking it for granted that no actual damage is done, 
 and the owner merely sues on account of the invasion 
 of his property, how is the amount of compensation to 
 be fixed upon? The owner has lost nothing; no part of 
 his possessions has been taken away ; nothing has been 
 injured or destroyed ; everything is left in exactly the 
 same condition as before the invasion. And yet, if the 
 law is strictly interpreted, the offender is liable. 
 
 Right of Way for Airships. 
 
 Somebody has suggested the organization of flying- 
 machine corporations as common carriers, which would 
 give them the right of eminent domain with power to 
 condemn a right of way. But what would they con- 
 demn? There is nothing tangible in the air. Railways 
 in condemning a right of way specify tangible property 
 (realty) within certain limits. How would an aviator 
 designate any particular right of way through the air 
 a certain number of feet in width, and a certain distance 
 from the ground? 
 
 And yet, should the higher courts hold to the letter 
 
CONSTRUCTION AND OPERATION 173 
 
 of the law and decide that aviators have no right to 
 navigate their craft over private property, something 
 will have to be done to get them out of the dilemma, as 
 aviation is too far advanced to be discarded. Fortu- 
 nately there is little prospect of any widespread antag- 
 onism among property owners so long as aviators re- 
 frain from making nuisances of themselves. 
 
 Possible Solution Offered. 
 
 One possible, solution is offered and that is to confine 
 the path of airships to the public highways so that no- 
 body's property rights would be invaded. In addition, 
 as a matter of promoting safety for both operators and 
 those who may happen to be beneath the airships as 
 they pass over a course, adoption of the French rules 
 are suggested. These are as follows : 
 
 Aeroplanes, when passing, must keep to the right, and 
 pass at a distance of at least 150 feet. They are free 
 from this rule when flying at altitudes of more than 100 
 feet. Every machine when flying at night or during 
 foggy weather must carry a green light on the right, 
 and a red light on the left, and a white headlight on the 
 front. 
 
 These are sensible rules, but may be improved upon 
 by the addition of a signal system of some kind, either 
 horn, whistle or bell. 
 
 Responsibility of Aviators. 
 
 Mr. Jay Carver Bossard, in recent numbers of Fly, 
 brings out some curious and interesting legal points in 
 connection with aviation, among which are the follow- 
 ing: 
 
 "Private parties who possess aerial craft, and desire 
 to operate the same in aerial territory other than their 
 own, must obtain from land owners special permission 
 
174 FLYING MACHINES: 
 
 to do so, such permission to be granted only by agree- 
 ment, founded upon a valid consideration. Otherwise, 
 passing over another's land will in each instance amount 
 to a trespass. 
 
 "Leaving this highly technical side of the question, 
 let us turn to another view: the criminal and tort liabil- 
 ity of owners and operators to airship passengers. If 
 A invites B to make an ascension with him in his ma- 
 chine, and B, knowing that A is merely an enthusiastic 
 amateur and far from being an expert, accepts and is 
 through A's innocent negligence injured, he has no 
 grounds for recovery. But if A contracts with B, to 
 transport him from one place to another, for a consid- 
 eration, and B is injured by the poor piloting of A, 
 A would be liable to B for damages which would result. 
 Now in order to safeguard such people as B, curious to 
 the point of recklessness, the law will have to require 
 all airship operators to have a license, and to secure 
 this license airship pilots will have to meet certain re- 
 quirements. Here again is a question. Who is going 
 to say whether an applicant is competent to pilot a bal- 
 loon or airship? 
 
 Fine for an Aeronaut. 
 
 "An aeroplane while maneuvering is suddenly caught 
 by a treacherous gale and swept to the ground. A crowd 
 of people hasten over to see if the aeronaut is injured, 
 and in doing so trample over Tax-payer Smith's garden, 
 much to the detriment of his - growing vegetables and 
 flowers. Who is liable for the damages? Queer as it 
 may seem, a case very similar to this was decided in 
 1823, in the New York supreme court, and it was held 
 that the aeronaut was liable upon the following grounds: 
 'To render one man liable in trespass for the acts of 
 others, it must appear either that they acted in concert, 
 
CONSTRUCTION AND OPERATION 175 
 
 or that the act of the one, ordinarily and naturally pro- 
 duced the acts of the others. Ascending in a balloon is 
 not an unlawful act, but it is certain that the aeronaut 
 has no control over its motion horizontally, but is at 
 the sport of the wind, and is to descend when and how 
 he can. His reaching the earth is a matter of hazard. 
 If his descent would according to the circumstances 
 draw a crowd of people around him, either out of curi- 
 osity, or for the purpose of rescuing him from a perilous 
 situation, all this he ought to have foreseen, and must be 
 responsible for.' 
 
 Air Not Really Free. 
 
 "The general belief among people is, that the air is 
 free. Not only free to breathe and enjoy, but free to 
 travel in, and that no one has any definite jurisdiction 
 over, or in any part of it. Now suppose this were made a 
 legal doctrine. Would a murder perpetrated above the 
 clouds have to go unpunished? Undoubtedly. For fel- 
 onies committed upon the high seas ample provision is 
 made for their punishment, but new provisions will have 
 to be made for crimes committed in the air. 
 
 Relations of Owner and Employee. 
 
 "It is a general rule of law that a master is bound to 
 provide reasonably safe tools, appliances and machines 
 for his servant. How this rule is going to be applied 
 in cases of aeroplanes, remains to be seen. The aero- 
 plane owner who hires a professional aeronaut, that is, 
 one who has qualified as an expert, owes him very little 
 legal duty to supply him with a perfect aeroplane. The 
 expert is supposed to know as much regarding the ma- 
 chine as the owner, if not more, and his acceptance of 
 his position relieves the owner from liability. When 
 the owner hires an amateur aeronaut to run the aero- 
 
176 FLYING MACHINES: 
 
 plane, and teaches him how to manipulate it, even though 
 the prescribed manner of manipulation will make flight 
 safe, nevertheless if the machine is visibly defective, or 
 known to be so, any injury which results to the aero- 
 naut the owner is liable for. 
 
 As to Aeroplane Contracts. 
 
 "At the present time there are many orders being 
 placed with aeroplane manufacturing companies. There 
 are some unique questions to be raised here under the 
 law of contract. It is an elementary principle of law 
 that no one can be compelled to complete a contract 
 which in itself is impossible to perform. For instance, 
 a contract to row a boat across the Atlantic in two 
 weeks, for a consideration, could never be enforced be- 
 cause it is within judicial knowledge that such an under- 
 taking is beyond human power. Again, contracts formed 
 for the doing of acts contrary to nature are never en- 
 forcible, and here is where our difficulty comes in. Is 
 it possible to build a machine or species of craft which 
 will transport a person or goods through the air? The 
 courts know that balloons are practical ; that is, they 
 know that a bag filled with gas has a lifting power and 
 can move through the air at an appreciable height. 
 Therefore, a contract to transport a person in such man- 
 ner is a good contract, and the conditions being favor- 
 able could undoubtedly be enforced. But the passen- 
 gers' right of action for injury would be very limited. 
 
 No Redress for Purchasers. 
 
 "In the case of giving warranties on aeroplanes, we 
 have yet to see just what a court is going to say. It is 
 easy enough for a manufacturer to guarantee to build a 
 machine of certain dimensions and according to certain 
 specifications, but when he inserts a clause in the con* 
 
CONSTRUCTION AND OPERATION 177 
 
 tract to the effect that the machine will raise itself from 
 the surface of the earth, defy the laws of gravity, and 
 soar in the heavens at the will of the aviator, he is to 
 say the least contracting to perform a miracle. 
 
 "Until aeroplanes have been made and accepted as 
 practical, no court will force a manufacturer to turn out 
 a machine guaranteed to fly. So purchasers can well 
 remember that if their machines refuse to fly they have 
 no redress against the maker, for he can always say, 
 'The industry is still in its experimental stage.' In 
 contracting, for an engine no builder will guarantee that 
 the particular engine will successfully operate the aero- 
 plane. In fact he could never be forced to live up to 
 such an agreement, should he agree to a stipulation of 
 that sort. The best any engine maker will guarantee 
 is to build an engine according to specifications." 
 
178 
 
 FLYING MACHINES: 
 
CHAPTER XX. 
 
 SOARING FLIGHT. 
 
 By Octave Chanute. 
 
 *There is a wonderful performance daily exhibited in 
 southern climes and occasionally seen in northerly 
 latitudes in summer, which has never been thoroughly 
 explained. It is the soaring or sailing flight of certain 
 varieties of large birds who transport themselves on rigid, 
 unflapping wings in any desired direction ; who in winds 
 of 6 to 20 miles per hour, circle, rise, advance, return and 
 remain aloft for hours without a beat of wing, save for 
 getting under way or convenience in various maneuvers. 
 They appear to obtain from the wind alone all the neces- 
 sary energy, even to. advancing dead against that wind. 
 This feat is so much opposed to our general ideas of 
 physics that those who have not seen it sometimes deny 
 its actuality, and those who have only occasionally wit- 
 nessed it subsequently doubt the evidence of their own 
 eyes. Others, who have seen the exceptional perform- 
 ances, speculate on various explanations, but the majority 
 give it up as a sort of "negative gravity." 
 
 Soaring Power of Birds. 
 
 The writer of this paper published in the "Aeronautical 
 Annual" for 1896 and 1897 an article upon the sailing 
 flight of birds, in which he gave a list of the authors who 
 
 Aeronautics. 
 
 179 
 
180 FLYING MACHINES: 
 
 had described such flight or had advanced theories for 
 its explanation, and he passed these in review. He also 
 described his own observations and submitted some com- 
 putations to account for the observed facts. These com- 
 putations were correct as far as they went, but they were 
 scanty. It w r as, for instance, shown convincingly by 
 analysis that a gull weighing 2.188 pounds, with a total 
 supporting surface of 2.015 square feet, a maximum body 
 cross-section of 0.126 square feet and a maximum cross- 
 section of wing edges of 0.098 square feet, patrolling on 
 rigid wings (soaring) on the weather side of a steamer 
 and maintaining an upward angle or attitude of 5 degrees 
 to 7 degrees above the horizon, in a wind blowing 12.78 
 miles an hour, which was deflected upward 10 degrees 
 to 20 degrees by the side of the steamer (these all being 
 carefully observed facts), was perfectly sustained at its 
 own "relative speed" of 17.88 miles per hour and ex- 
 tracted from the upward trend of the wind sufficient en- 
 ergy to overcome all the resistances, this energy 
 amounting to 6.44 foot-pounds per second. 
 
 Great Power of Gulls. 
 
 It was shown that the same bird in flapping flight in 
 calm air, with an attitude or incidence of 3 degrees to 5 
 degrees above the horizon and a speed of 20.4 miles an 
 hour was well sustained and expended 5.88 foot-pounds 
 per second, this being at the rate of 204 pounds sustained 
 per horsepower. It was stated also that a gull in its ob- 
 served maneuvers, rising up from a pile head on unflap- 
 ping wings, then plunging forward against the wind and 
 subsequently rising higher than his starting point, must 
 either time his ascents and descents exactly with the var- 
 iations in wind velocities, or must meet a wind billow 
 rotating on a horizontal axis and come to a poise on its 
 crest, thus availing of an ascending trend. 
 
CONSTRUCTION AND OPERATION 
 
 181 
 
 But the observations failed to demonstrate that the 
 variations of the wind gusts and the movements of the 
 bird were absolutely synchronous, and it was conjectured 
 that the peculiar shape of the soaring wing of certain 
 birds, as differentiated from the flapping wing, might, 
 when experimented upon, hereafter account for the per- 
 formance. 
 
 Mystery to be Explained. 
 
 These computations, however satisfactory they were 
 for the speed of winds observed, failed to account for the 
 
 Farman Biplane in Flight. 
 
 observed spiral soaring of buzzards in very light winds 
 and the writer was compelled to confess: "Now, this 
 spiral soaring in steady breezes of 5 to 10 miles per hour 
 which are apparently horizontal, and through which the 
 bird maintains an average speed of about 20 miles an 
 hour, is the mystery to be explained. It is not accounted 
 for, quantitatively, by any of the theories which have 
 been advanced, and it is the one performance which has 
 led some observers to claim that it was done through 
 'aspiration,' i. e., that a bird acted upon by a current, ac- 
 
182 FLYING MACHINES: 
 
 tually drew forward into that current against its exact 
 direction of motion." 
 
 Buzzards Soar in Dead Calm. 
 
 A still greater mystery was propounded by the few 
 observers who asserted that they had seen buzzards soar- 
 ing in a dead calm, maintaining their elevation and their 
 speed. Among these observers was Mr. E. C. Huffaker, 
 at one time assistant experimenter for Professor Langley. 
 The writer believed and said then that he must in some 
 way have been mistaken, yet, to satisfy himself, he paid 
 several visits to Mr. Huffaker, in Eastern Tennessee and 
 took along his anemometer. He saw quite a number of 
 buzzards sailing at a height of 75 to 100 feet in breezes 
 measuring 5 or 6 miles an hour at the surface of the 
 ground, and once he saw one buzzard soaring apparently 
 in a dead calm. 
 
 The writer was fairly baffled. The bird was not simply 
 gliding, utilizing gravity or acquired momentum, he was 
 actually circling horizontally in defiance of physics and 
 mathematics. It took two years and a whole series of 
 further observations to bring those two sciences into 
 accord with the facts. 
 
 Results of Close Observations. 
 
 Curiously enough the key to the performance of cir- 
 cling in a light wind or a dead calm was not found 
 through the usual way of gathering human knowledge, 
 i. e., through observations and experiment. These had 
 failed because I did not know what to look for. The 
 mystery was, in fact, solved by an eclectic process of 
 conjecture and computation, but once these computations 
 indicated what observations should be made, the results 
 gave at once the reasons for the circling of the birds, for 
 their then observed attitude, and for the necessity of an 
 
CONSTRUCTION AND OPERATION 183 
 
 independent initial sustaining speed before soaring be- 
 gan. Both Mr. Huffaker and myself verified the data 
 many times and I made the computations. 
 
 These observations disclosed several facts : 
 
 ist. That winds blowing five to seventeen miles per 
 hour frequently had rising trends of 10 degrees to 15 
 degrees, and that upon occasions when there seemed to be 
 absolutely no wind, there was often nevertheless a local 
 rising of the air estimated at a rate of four to eight miles 
 or more per hour. This was ascertained by watching 
 thistledown, and rising fogs alongside of trees or hills of 
 known height. Everyone will readily realize that when 
 walking at the rate of four to eight miles an hour in a 
 dead calm the "relative wind" is quite inappreciable to 
 the senses and that such a rising air would not be noticed. 
 
 2nd. That the buzzard, sailing in an apparently dead 
 horizontal calm, progressed at speeds of fifteen to eight- 
 een miles per hour, as measured by his shadow on the 
 ground. It was thought that the air was then possibly 
 rising 8.8 feet per second, or six miles per hour. 
 
 3rd. That when soaring in very light winds the angle 
 of incidence of the buzzards was negative to the horizon 
 i. e., that when seen coming toward the eye, the after- 
 noon light shone on the back instead of on the breast, 
 as would have been the case had the angle been inclined 
 above the horizon. 
 
 4th. That the sailing performance only occurred after 
 the bird had acquired an initial velocity of at least fifteen 
 or eighteen miles per hour, either by industrious flapping 
 or by descending from a perch. 
 
 An Interesting Experiment. 
 
 5th. That the whole resistance of a stuffed buzzard, 
 at a negative angle of 3 degrees in a current of air of 
 15.52 miles per hour, was 0.27 pounds. This test was 
 
184 FLYING MACHINES: 
 
 kindly made for the writer by Professor A. F. Zahm in 
 the "wind tunnel" of the Catholic University at Wash- 
 ington, D. C., who, moreover, stated that the resistance 
 of a live bird might be less, as the dried plumage could 
 not be made to lie smooth. 
 
 This particular buzzard weighed in life 4.25 pounds, 
 the area of his wings and body was 4.57 square feet, the 
 maximum cross-section of his body was o.no square feet, 
 and that of his wing edges when fully extended was 
 0.244 square feet. 
 
 With these data, it became surprisingly easy to com- 
 pute the performance with the coefficients of Lilienthal 
 for various angles of incidence and to demonstrate how 
 this buzzard could soar horizontally in a dead horizontal 
 calm, provided that it was not a vertical calm, and that 
 the air was rising at the rate of four or six miles per 
 hour, the lowest observed, and quite inappreciable with- 
 out actual measuring. 
 
 Some Data on Bird Power. 
 
 The most difficult case is purposely selected. For if 
 we assume that the bird has previously acquired an ini- 
 tial minimum speed of seventeen miles an hour (24.93 
 feet per second, nearly the lowest measured), and that 
 the air was rising vertically six miles an hour (8.80 feet 
 per second), then we have as the trend of the "relative 
 wind" encountered : 
 
 6 
 - 0.353, or tne tangent of 19 26'. 
 
 I? 
 
 which brings the case into the category of rising wind 
 effects. But the bird was observed to have a negative 
 angle to the horizon of about 3, as near as could be 
 guessed, so that his angle of incidence to the "relative 
 wind" was reduced to 16 26'. 
 
CONSTRUCTION AND OPERATION 185 
 
 The relative speed of his soaring was therefore: 
 
 Velocity = V 1 7 2 + & = 18.03 miles per hour. 
 
 At this speed, using the Langley co-efficient recently 
 practically confirmed by the accurate experiments of Mr. 
 Eiffel, the air pressure would be : 
 
 i8.O3 2 X 0.00327 = 1.063 pounds per square foot. 
 
 If we apply LilienthaFs co-efficients for an angle of 
 16 26', we have for the force in action : 
 
 Normal: 4.57 X 1-063 X 0.912 = 4.42 pounds. 
 
 Tangential: 4.57 X 1.063 X 0.074 = 0.359 pounds, 
 which latter, being negative, is a propelling force. 
 
 Results Astonish Scientists. 
 
 Thus we have a bird weighing 4.25 pounds not only 
 thoroughly supported, but impelled forward by a force 
 of 0.359 pounds, at seventeen miles per hour, while the 
 experiments of Professor A. F. Zahm showed that the 
 resistance at 15.52 miles per hour was only 0.27 pounds, 
 
 J7 2 
 or 0.27 X 0.324 pounds, at seventeen miles an 
 
 I5-52 2 
 hour. 
 
 These are astonishing results from the data obtained, 
 and they lead to the inquiry whether the energy of the 
 rising air is sufficient to make up the losses which occur 
 by reason of the resistance and friction of the bird's body 
 and wings, which, being rounded, do not encounter air 
 pressures in proportion to their maximum cross-section. 
 
 We have no accurate data upon the co-efficients to ap- 
 ply and estimates made by myself proved to be much 
 smaller than the 0.27 pounds resistance measured by 
 Professor Zahm, so that we will figure with the latter 
 as modified. As the speed is seventeen miles per hour, or 
 24.93 feet per second, we have for the work : 
 
 Work done, 0.324 X 24.93 8.07 foot pounds per sec- 
 ond. 
 
186 FLYING MACHINES: 
 
 Endorsed by Prof. Marvin. 
 
 Corresponding energy of rising air is not sufficient at 
 four miles per hour. This amounts to but 2.10 foot pounds 
 per second, but if we assume that the air was rising at 
 the rate of seven miles per hour (10.26 feet per second), 
 at which the pressure with the Langley coefficient would 
 be 0.16 pounds per square foot, we have on 4.57 square 
 feet for energy of rising air: 4.57 X 0.16 X 10.26 = 7.50 
 foot pounds per second, which is seen to be still a little 
 too small, but well within the limits of error, in view of 
 the hollow shape of the bird's wings, which receive 
 greater pressure than the flat planes experimented upon 
 by Langley. 
 
 These computations were chiefly made in January, 
 1899, and were communicated to a few friends, who found 
 no fallacy in them, but thought that few aviators would 
 understand them if published. They were then submitted 
 to Professor C. F. Marvin of the Weather Bureau, who 
 is well known as a skillful physicist and mathematician. 
 He wrote that they were, theoretically, entirely sound 
 and quantitatively, probably, as accurate as the present 
 state of the measurements of wind pressures permitted. 
 The writer determined, however, to withhold publication 
 until the feat of soaring flight had been performed by 
 man, partly because he believed that, to ensure safety, it 
 would be necessary that the machine should be equipped 
 witli a motor in order to supplement any deficiency in 
 wind force. 
 
 Conditions Unfavorable for Wrights. 
 
 The feat would have been attempted in 1902 by Wright 
 brothers if the local circumstances had been more favor- 
 able. They 'were experimenting on "Kill Devil Hill," 
 ne?.r Kitty Hawk, N. C. This sand hill, about 100 feet 
 high, is bordered by a smooth beach on the side whence 
 
CONSTRUCTION AND OPERATION 187 
 
 come the sea breezes, but has marshy ground at the back. 
 Wright brothers were apprehensive that if they rose on 
 the ascending current of air at the front and began to 
 circle like the birds, they might be carried by the de- 
 scending current past the back of the hill and land in 
 the marsh. Their gliding machine offered no greater 
 head resistance in proportion than the buzzard, and their 
 
 Latham's Antoinette Monoplane in Flight. 
 
 gliding angles of descent are practically as favorable, but 
 the birds performed higher up in the air than they. 
 
 Langley's Idea of Aviation. 
 
 Professor Langley said in concluding his paper upon 
 "The Internal Work of the Wind" : 
 
 "The final application of these principles to the art of 
 aerodromics seems, then, to be, that while it is not likely 
 that the perfected aerodrome will ever be able to dis- 
 pense altogether with the ability to rely at intervals on 
 some internal source of power, it will not be indispen- 
 sable that this aerodrome of the future shall, in order to 
 
188 FLYING MACHINES: 
 
 go any distance even to circumnavigate the globe with- 
 out alighting need to carry a weight of fuel which 
 would enable it to perform this journey under conditions 
 analogous to those of a steamship, but that the fuel and 
 weight need only be such as to enable it to take care of 
 itself in exceptional moments of calm." 
 
 Now that dynamic flying machines have been evolved 
 and are being brought under control, it seems to be 
 worth while to make these computations and the suc- 
 ceeding explanations known, so that some bold man will 
 attempt the feat of soaring like a bird. The theory un- 
 derlying the performance in a rising wind is not new, 
 it has been suggested by Penaud and others, but it has 
 attracted little attention because the exact data and the 
 maneuvers required were not known and the feat had 
 not yet been performed by a man. The puzzle has al- 
 ways been to account for the observed act in very light 
 winds, and it is hoped that by the present selection of 
 the most difficult case to explain i. e., the soaring in a 
 dead horizontal calm somebody will attempt the exploit. 
 
 Requisites for Soaring Flights. 
 
 The following are deemed to be the requisites and 
 maneuvers to master the secrets of soaring flight: 
 
 1st. Develop a dynamic flying machine weighing 
 about one pound per square foot of area, with stable 
 equilibrium and under perfect control, capable of gliding 
 by gravity at angles of one in ten (5^4) in still air. 
 
 2nd. Select locations where soaring birds abound and 
 occasions where rising trends of gentle winds are fre- 
 quent and to be relied on. 
 
 3rd. Obtain an initial velocity of at least 25 feet per 
 second before attempting to soar. 
 
 4th. So locate the center of gravity that the apparatus 
 shall assume a negative angle, fore and aft, of about 3. 
 
CONSTRUCTION AND OPERATION 
 
 189 
 
190 FLYING MACHINES: 
 
 Calculations show, however, that sufficient propelling 
 force may still exist at o, but disappears entirely at 
 + 4. 
 
 5th. Circle like the bird. Simultaneously with the 
 steering, incline the apparatus to the side toward which 
 it is desired to turn, so that the centrifugal force shall 
 be balanced by the centripetal force. The amount of the 
 required inclination depends upon the speed and on the 
 radius of the circle swept over. 
 
 6th. Rise spirally like the bird. Steer with the hori- 
 zontal rudder, so as to descend slightly when going 
 with the wind and to ascend when going against the 
 wind. The bird circles over one spot because the rising 
 trends of wind are generally confined to small areas or 
 local chimneys, as pointed out by Sir H. Maxim and 
 others. 
 
 7th. Once altitude is gained, progress may be made 
 in any direction by gliding downward by gravity. 
 
 The bird's flying apparatus and skill are as yet infinite- 
 ly superior to those of man, but there are indications that 
 within a few years the latter may evolve more accurately 
 proportioned apparatus and obtain absolute control over 
 it. 
 
 It is hoped, therefore, that if there be found no radical 
 error in the above computations, they will carry the con- 
 viction that soaring flight is not inaccessible to man, as 
 it promises great economies of motive power in favorable 
 localities of rising winds. 
 
 The writer will be grateful to experts who may point 
 out any mistake committed in data or calculations, and 
 will furnish additional information to any aviator who 
 may wish to attempt the feat of soaring. 
 
CHAPTER XXI. 
 
 FLYING MACHINES VS. BALLOONS. 
 
 While wonderful success has attended the develop- 
 ment of the dirigible (steerable) balloon the most ardent 
 advocates of this form of aerial navigation admit that it 
 has serious drawbacks. Some of these may be described 
 as follows: 
 
 Expense and Other Items. 
 
 .Great Initial Expense. The modern dirigible balloon 
 costs a fortune. The Zeppelin, for instance, costs more 
 than $100,000 (these are official figures). 
 
 Expense of Inflation. Gas evaporates rapidly, and a 
 balloon must be re-inflated, or partially re-inflated, every 
 time it is used. The Zeppelin holds 460,000 cubic feet 
 of gas which, even at $i per thousand, would cost $460. 
 
 Difficulty of Obtaining Gas. If a balloon suddenly 
 becomes deflated, by accident or atmospheric conditions, 
 far from a source of gas supply, it is practically worth- 
 less. Gas must be piped to it, or the balloon carted to 
 the gas house an expensive proceeding in either event. 
 
 Lack of Speed and Control. 
 
 Lack of Speed. Under the most favorable conditions 
 the maximum speed of a balloon is 30 miles an hour. 
 Its great bulk makes the high speed attained by flying 
 machines 'impossible. 
 
 Difficulty of Control. While the modern dirigible bal- 
 
 191 
 
192 FLYING MACHINES: 
 
 loon is readily handled in calm or light winds, its bulk 
 makes it difficult to control in heavy winds. 
 
 The Element of Danger. Numerous balloons have 
 been destroyed by lightning and similar causes. One of 
 the largest of the Zeppelins was thus lost at Stuttgart 
 in 1908. 
 
 Some Balloon Performances. 
 
 It is only a matter of fairness to state that, under 
 favorable conditions, some very creditable records have 
 been made with modern balloons, viz : 
 
 November 23d, 1907, the French dirigible Patrie, trav- 
 elled 187 miles in 6 hours and 45 minutes against a 
 light wind. This was a little over 28 miles an hour. 
 
 The Clement-Bayard, another French machine, sold 
 to the Russian government, made a trip of 125 miles at 
 a rate of 27 miles an hour. 
 
 Zeppelin No. 3, carrying eight passengers, and having 
 a total lifting capacity of 5,500 pounds of ballast in ad- 
 dition to passengers, weight of equipment, etc., was 
 tested in October, 1906, and made 67 miles in 2 hours 
 and 17 minutes, about 30 miles an hour. 
 
 These are the best balloon trips on record, and show 
 forcefully the limitations of speed, the greatest being not 
 over 30 miles an hour. 
 
 Speed of Flying Machines. 
 
 Opposed to the balloon performances we have flying 
 machine trips (of authentic records) as follows : 
 
 Bleriot monoplane in 1908 52 miles an hour. 
 
 Delagrange June 22, 1908 ioj^ miles in 16 minutes, 
 approximately 42 miles an hour. 
 
 Wrights October, 1905 the machine was then in its 
 infancy 24 miles in 38 minutes, approximately 44 miles 
 an hour. On December 31, 1908, the Wrights made 77 
 miles in 2 hours and 20 minutes. 
 
CONSTRUCTION AND OPERATION 193 
 
 Lambert, a pupil of the Wrights, and using a Wright 
 biplane, on October 18, 1909, covered 29.82 miles in 49 
 minutes and 39 seconds, being at the rate of 36 miles 
 an hour. This flight was made at a height of 1,312 feet. 
 
 Latham October 21, 1909 made a short flight, about, 
 ii minutes, in the teeth of a 40 mile gale, at Blackpool, 
 Eng. He used an Antoniette monoplane, and the official 
 report says : "This exhibition of nerve, daring and ability 
 is unparalled in the history of aviation." 
 
 Farman October 20, 1909 was in the air for I hour, 
 32 min., 16 seconds, travelling 47 miles, 1,184 yards, a 
 duration record for England. 
 
 Paulhan January 18, 1910 47^ miles at the rate of 
 45 miles an hour, maintaining an altitude of from 1,000 
 to 2,000 feet. 
 
 Expense of Producing Gas. 
 
 Gas is indispensable in the operation of dirigible bal- 
 loons, and gas is expensive. Besides this it is not always 
 possible to obtain it in sufficient quantities even in large 
 cities, as the supply on hand is generally needed for 
 regular customers. Such as can be had is either water 
 or coal gas, neither of which is as efficient in lifting 
 power as hydrogen. 
 
 Hydrogen is the lightest and consequently the most 
 buoyant of all known gases. It is secured commercially 
 by treating zinc or iron with dilute sulphuric or hy- 
 drochloric acid. The average cost may be safely placed 
 at $10 per 1,000 feet so that, to inflate a balloon of the 
 size of the Zeppelin, holding 460,000 cubic feet, would 
 cost $4,600. 
 
 Proportions of Materials Required. 
 
 In making hydrogen gas it is customary to allow 20 
 per cent for loss between the generation and the intro- 
 duction of the gas into the balloon. Thus, while the 
 
 13 
 
194 FLYING MACHINES: 
 
 formula calls for iron 28 times heavier than the weight 
 of the hydrogen required, and acid 49 times heavier, the 
 real quantities are 20 per cent greater. Hydrogen weighs 
 about 0.09 ounce to the cubic foot. Consequently if we 
 need say 450,000 cubic feet of gas we must have 2,531.25 
 pounds in weight. To produce this, allowing for the 20 
 percent loss, we must have 35 times its weight in iron, 
 or over 44 tons. Of acid it would take 60 times the 
 weight of the gas, or nearly 76 tons. 
 
 In Time of Emergency. 
 
 These figures are appalling, and under ordinary con- 
 ditions would be prohibitive, but there are times when 
 the balloon operator, unable to obtain water or coal gas, 
 must foot the bills. In military maneuvers, where the 
 field of operation is fixed, it is possible to furnish sup- 
 plies of hydrogen gas in portable cylinders, but on long 
 trips where sudden leakage or other cause makes descent 
 in an unexpected spot unavoidable, it becomes a question 
 of making your own hydrogen gas or deserting the bal- 
 loon. And when this occurs the balloonist is up against 
 another serious proposition can he find the necessary 
 zinc or iron? Can he get the acid? 
 
 Balloons for Commercial Use. 
 
 Despite all this the balloon has its uses. If there is to 
 be such a thing as aerial navigation in a commercial 
 way the carrying of freight and passengers it will 
 come through the employment of such monster balloons 
 as Count Zeppelin is building. But even then the carry- 
 ing capacity must of necessity be limited. The latest 
 Zeppelin creation, a monster in size, is 450 feet long, 
 and 425^ feet in diameter. The dimensions are such as 
 to make all other balloons look like pigmies ; even many 
 ocean-going steamers are much smaller, and yet its pas- 
 
CONSTRUCTION AND OPERATION 
 
 195 
 
196 FLYING MACHINES: 
 
 senger capacity is very small. On its 36-hour flight in 
 May, 1909, the Zeppelin, carried only eight passengers. 
 The speed, however, was quite respectable, 850 miles 
 being covered in the 36 hours, a trifle over 23 miles an 
 hour. The reserve buoyancy, that is the total lifting 
 capacity aside from the weight of the airship and its 
 equipment, is estimated at three tons. 
 
CHAPTER XXII. 
 
 PROBLEMS OF AERIAL FLIGHT. 
 
 In a lecture before the Royal Society of Arts, reported 
 in Engineering, F. W. Lanchester took the position that 
 practical flight was not the abstract question which some 
 apparently considered it to be, but a problem in loco- 
 motive engineering. The flying machine was a loco- 
 motive appliance, designed not merely to lift a weight, 
 but to transport it elsewhere, a fact which should be suffi- 
 ciently obvious. Nevertheless one of the leading scientific 
 men of the day advocated a type in which this, the 
 main function of the flying machine, was overlooked. 
 When the machine was considered as a method of trans- 
 port, the vertical screw type, or helicopter, became at 
 once ridiculous. It had, nevertheless, many advocates 
 who had some vague and ill-defined notion of subsequent 
 motion through the air after the weight was raised. 
 
 Helicopter Type Useless. 
 
 When efficiency of transport was demanded, the heli- 
 copter type was entirely out of court. Almost all of 
 its advocates neglected the effect of the motion of the 
 machine through the air on the efficiency of the ver- 
 tical screws. They either assumed that the motion was 
 so slow as not to matter, or that a patch of still air accom- 
 panied the machine in its flight. Only one form of this 
 type had any possibility of success. In this there were 
 two screws running on inclined axles one on each side 
 of the weight to be lifted. The action of such inclined 
 screw was curious, and in a previous lecture he had 
 
 197 
 
198 FLYING MACHINES: 
 
 pointed out that it was almost exactly the same as that 
 of a bird's wing. In high-speed racing craft such in- 
 clined screws were of necessity often used, but it was 
 at a sacrifice of their efficiency. In any case the effi- 
 ciency of the inclined-screw helicopter could not com- 
 pare with that of an aeroplane, and that type might be 
 dismissed from consideration so soon as efficiency be- 
 came the ruling factor of the design. 
 
 Must Compete With Locomotive. 
 
 To justify itself the aeroplane must compete, in some 
 regard or other, with other locomotive appliances, per- 
 forming one or more of the purposes of locomotion more 
 efficiently than existing systems. It would be no use 
 unless able to stem air currents, so that its velocity must 
 be greater than that of the worst winds liable to be en- 
 countered. To illustrate the limitations imposed on the 
 motion of an aeroplane by wind velocity, Mr. Lanchester 
 gave the diagrams shown in Figs. I to 4. The circle 
 in each case was, he said, described with a radius equal 
 to the speed of the aeroplane in still air, from a center 
 placed "down-wind" from the aeroplane by an amount 
 equal to the velocity of the wind. 
 
 Fig. I therefore represented the case in which the 
 air was still, and in this case the aeroplane represented 
 by A had perfect liberty of movement in any direction 
 
 In Fig. 2 the velocity of the w r ind was half that of the 
 aeroplane, and the latter could still navigate in any 
 direction, but its speed against the wind was only one- 
 third of its speed with the wind. 
 
 In Fig. 3 the velocity of the wind was equal to that 
 of the aeroplane, and then motion against the wind was 
 impossible ; but it could move to any point of the 
 circle, but not to any point lying to the left of the tan- 
 gent A B. Finally, when the wind had a greater 
 
CONSTRUCTION AND OPERATION 
 
 199 
 
 speed than the aeroplane, as in Fig. 4, the machine could 
 move only in directions limited by the tangents A C 
 and A D. 
 
 Matter of Fuel Consumption. 
 
 Taking the case in which the wind had a speed equal 
 to half that of the aeroplane, Mr. Lanchester said that 
 for a given journey out and home, down wind and back, 
 the aeroplane would require 30 per cent more fuel than 
 if the trip were made in still air; while if the journey 
 
 was made at right angles to the direction of the wind, 
 the fuel needed would be 15 per cent more than in a 
 calm. This 30 per cent extra was quite a heavy enough 
 addition to the fuel ; and to secure even this figure it 
 was necessary that the aeroplane should have a speed of 
 twice that of the maximum wind in which it was desired 
 to operate the machine. Again, as stated in the last 
 lecture, to insure the automatic stability of the machine 
 it was necessary that the aeroplane speed should be 
 largely in excess of that of the gusts of wind liable to 
 be encountered. 
 
200 FLYING MACHINES: 
 
 Eccentricities of the Wind. 
 
 There was, Mr. Lanchester said, a loose connection 
 between the average velocity of the wind and the max- 
 imum speed of the gusts. When the average speed of 
 the wind was 40 miles per hour, that of the gusts might 
 be equal or more. At one moment there might be a 
 calm or the direction of the wind even reversed, followed, 
 the next moment, by a violent gust. About the same 
 minimum speed was desirable for security against gusts 
 as was demanded by other considerations. Sixty miles 
 an hour was the least figure desirable in an aeroplane, 
 and this should be exceeded as much as possible. Ac- 
 tually, the Wright machine had a speed of 38 miles per 
 hour, while Farman's Voisin machine flew at 45 miles 
 per hour. 
 
 Both machines were extremely sensitive to high winds, 
 and the speaker, in spite of newspaper reports to the 
 contrary, had never seen either flown in more than a 
 gentle breeze. The damping out of the oscillations of 
 the flight path, discussed in the last lecture, increased 
 with the fourth power of the natural velocity of flight, 
 and rapid damping formed the easiest, and sometimes 
 the only, defense against dangerous oscillations. A 
 machine just stable at 35 miles per hour would have 
 reasonably rapid damping if its speed were increased to 
 60 miles per hour. 
 
 Thinks Use Is Limited. 
 
 It was, the lecturer proceeded, inconceivable that any 
 very extended use should be made of the aeroplane unless 
 the speed was much greater than that of the motor car. 
 It might in special cases be of service, apart from this 
 increase of speed, as in the exploration of countries 
 destitute of roads, but it would have no general utility. 
 With an automobile averaging 25 to 35 miles per hour, 
 
CONSTRUCTION AND OPERATION 201 
 
 almost any part of Europe, Russia excepted, was at- 
 tainable in a day's journey. A flying machine of but 
 equal speed would have no advantages, but if the speed 
 could be raised to 90 or 100 miles per hour, the whole 
 continent of Europe would become a playground, every 
 part being within a daylight flight of Berlin. Further, 
 some marine craft now had speeds of 40 miles per hour, 
 and efficiently to follow up and report movements of 
 such vessels an aeroplane should travel at 60 miles per 
 hour at least. Hence from all points of view appeared 
 the imperative desirability of very high velocities of 
 flight. The difficulties of achievement were, however, 
 great. 
 
 Weight of Lightest Motors. 
 
 As shown in the first lecture of his course, the resist- 
 ance to motion was nearly independent of the velocity, 
 so that the total work done in transporting a given 
 weight was nearly constant. Hence the question of fuel 
 economy was not a bar to high velocities of flight, though 
 should these become excessive, the body resistance might 
 constitute a large proportion of the total. The horse- 
 power required varied as the velocity, so the factor gov- 
 erning the maximum velocity of flight was the horse- 
 power that could be developed on a given weight. At 
 present the weight per horsepower of feather-weight 
 motors appeared to range from 2% pounds up to 7 
 pounds per brake horsepower, some actual figures being 
 as follows : 
 
 Antoinette , 5 Ibs. 
 
 Eiat 3 Ibs. 
 
 Gnome Under 3 Ibs. 
 
 Metallurgic 8 Ibs. 
 
 Renault 7 Ibs. 
 
 Wright 6 Ibs. 
 
202 FLYING MACHINES: 
 
 Automobile engines, on the other hand, commonly 
 weighed 12 pounds to 13 pounds per brake horsepower. 
 
 For short flights fuel economy was of less importance 
 than a saving in the weight of the engine. For long 
 flights, however, the case was different. Thus, if the 
 gasolene consumption was J^ pound per horsepower hour, 
 and the engine weighed 3 pounds per brake horsepower, 
 the fuel needed for a six-hour flight would weigh as much 
 as the engine, but for half an hour's flight its weight 
 would be unimportant. 
 
 Best Means of Propulsion. 
 
 The best method of propulsion was by the screw, 
 which acting in air was subject to much the same con- 
 ditions as obtained in marine work. Its efficiency de- 
 pended on its diameter and pits and on its position, 
 whether in front of or behind the body propelled. From 
 this theory of dynamic support, Mr. Lanchester pro- 
 ceeded, the efficiency of each element of a screw pro- 
 peller could be represented by curves such as were given 
 in his first lecture before the society, and from these 
 curves the over-all efficiency of any proposed propeller 
 could be computed, by mere inspection, with a fair de- 
 gree of accuracy. These curves showed that the tips of 
 long-bladed propellers were inefficient, as was also the 
 portion of the blade near the root. In actual marine 
 practice the blade from boss to tip was commonly of 
 such a length that the over-all efficiency was 95 per cent 
 of that of the most efficient element of it. 
 
 Advocates Propellers in Rear. 
 
 From these curves the diameter and appropriate pitch 
 of a screw could be calculated, .and the number of rev- 
 olutions was then fixed. Thus, for a speed of 80 feet 
 per second the pitch might come out as 8 feet, in which 
 
CONSTRUCTION AND OPERATION 203 
 
 case the revolutions would be 600 per minute, which 
 might, however, be too low for the motor, it was then 
 necessary either to gear down the propeller, as was done 
 in the Wright machine, or, if it was decided to drive it 
 direct, to sacrifice some of the efficiency of the propeller. 
 An analogous case arose in the application of the steam 
 turbine to the propulsion of cargo boats, a problem as 
 yet unsolved. The propeller should always be aft, so 
 that it could abstract energy from the wake current, and 
 also so that its wash was clear of the body propelled. 
 The best possible efficiency was about 70 per cent, and 
 it was safe to rely upon 66 per cent. 
 
 Benefits of Soaring Flight. 
 
 There was, Mr. Lanchester proceeded, some possibility 
 of the aeronaut reducing the power needed for transport 
 by his adopting the principle of soaring flight, as exem- 
 plified by some birds. There were, he continued, two 
 different modes of soaring flight. In the one the bird 
 made use of the upward current of air often to be found 
 in the neighborhood of steep vertical cliffs. These cliffs 
 deflected the air upward long before it actually reached 
 the cliff, a whole region below being thus the seat of 
 an upward current. Darwin has noted that the condor 
 was only to be found in the neighborhood of such cliffs. 
 Along the south coast also the gulls made frequent use 
 of the up currents due to the nearly perpendicular chalk 
 cliffs along the shore. 
 
 In the tropics up currents were also caused by tem- 
 perature differences. Cumulus clouds, moreover, were 
 nearly always the terminations of such up currents of 
 heated air, which, on cooling by expansion in the upper 
 regions, deposited their moisture as fog. These clouds 
 might, perhaps, prove useful in the future in showing 
 the aeronaut where up currents were to be found. An- 
 
204 FLYING MACHINES: 
 
 other mode of soaring flight was that adopted by the 
 albatross, which took advantage of the fact that the air 
 moved in pulsations, into which the bird fitted itself, 
 being thus able to extract energy from the wind. 
 Whether it would be possible for the aeronaut to employ 
 a similar method must be left to the future to decide. 
 
 Main Difficulties in Aviation. 
 
 In practical flight difficulties arose in starting and in 
 alighting. There was a lower limit to the speed at 
 which the machine was stable, and it was inadvisable to 
 leave the ground till this limit was attained. Similarly, 
 in alighting it was inexpedient to reduce the speed below 
 the limit of stability. This fact constituted a difficulty 
 in the adoption of high speeds, since the length of run 
 needed increased in proportion to the square of the 
 velocit} 7 ". This drawback could, however, be surmounted 
 by forming starting and alighting 1 grounds of ample size. 
 He thought it quite likely in the future that such grounds 
 would be considered as essential to the flying machine 
 as a seaport was to an ocean-going steamer or as a road 
 was to the automobile. 
 
 Requisites of Flying Machine. 
 
 Flying machines were commonly divided into mono- 
 planes and biplanes, according as they had one or two 
 supporting surfaces. The distinction was not, however, 
 fundamental. To get the requisite strength some form 
 of girder framework was necessary, and it was a mere 
 question of convenience whether the supporting surface 
 was arranged along both the top and the bottom of this 
 girder, or along the bottom only. The framework adopted 
 universally was of wood braced by ties of pianoforte 
 wire, an arrangement giving the stiffness desired with 
 the least possible weight. Some kind of chassis was also 
 necessary. 
 
CHAPTER XXIII. 
 
 AMATEURS MAY USE WRIGHT PATENTS. 
 
 Owing- to the fact that the Wright brothers have en- 
 joined a number of professional aviators from using 
 their system of control, amateurs have been slow to 
 adopt it. They recognize its merits, and would like to 
 use the system, but have been apprehensive that it 
 might involve them in litigation. There is no danger 
 of this, as will be seen by the following statement made 
 by the Wrights : 
 
 What Wright Brothers Say. 
 
 "Any amateur, any professional who is not exhibiting 
 for money, is at liberty to use our patented devices. 
 We shall be glad to have them do so, and there will be 
 no interference on our part, by legal action, or otherwise. 
 The only men we proceed against are those who, with- 
 out our permission, without even asking our consent, 
 coolly appropriate the results of our labors and use them 
 for the purpose of making money. Curtiss, Delagrange, 
 Voisin, and all the rest of them who have used our 
 devices have done so in money-making exhibitions. So 
 long as there is any money to be made by the use of the 
 products of our brains, we propose to have it ourselves. 
 It is the only way in which we can get any return for 
 the years of patient work we have given to the problem 
 of aviation. On the other hand, any man who wants 
 to use these devices for the purpose of pleasure, or the 
 advancement of science, is welcome to do so, without 
 money and without price. This is fair enough, is it not?" 
 
 205 
 
206 PLYING MACHINES: 
 
 Basis of the Wright Patents. 
 
 In a flying" machine a normally flat aeroplane having 
 lateral marginal portions capable of movement to dif- 
 ferent positions above or below the normal plane of the 
 body of the aeroplane, such movement being about an 
 axis transverse to the line of flight, whereby said lateral 
 marginal portions may be moved to different angles rel- 
 atively to the normal plane of the body of the aero- 
 plane, so as to present to the atmosphere different angles 
 of incidence, and means for so moving said lateral mar- 
 ginal portions, substantially as described. 
 
 Application of vertical struts near the ends having 
 flexible joints. 
 
 Means for simultaneously imparting such movement 
 to said lateral portions to different angles relatively to 
 each other. 
 
 Refers to the movement of the lateral portions on the 
 same side to the same angle. 
 
 Means for simultaneously moving vertical rudder so 
 as to present to the wind that side thereof nearest the 
 side of the aeroplane having the smallest angle of in- 
 cidence. 
 
 Lateral stability is obtained by warping the end wings 
 by moving the lever at the right hand of the operator, 
 connection being made by wires from the lever to the 
 wing tips. The rudder may also be curved or warped in 
 similar manner by lever action. 
 
 Wrights Obtain an Injunction. 
 
 In January, 1910, Judge Hazel, of the United States 
 Circuit Court, granted a preliminary injunction restrain- 
 ing the Herring-Curtiss Co., and Glenn H. Curtiss, from 
 manufacturing, selling, or using for exhibition purposes 
 the machine known as the Curtiss aeroplane. The in- 
 junction was obtained on the ground that the Curtiss 
 
CONSTRUCTION AND OPERATION 
 
 207 
 
 machine is an infringement upon the Wright patents in 
 the matter of wing warping and rudder control. 
 
 It is not the purpose qf the authors to discuss the sub- 
 ject pro or con. Such discussion would have no proper 
 place in a volume of this kind. It is enough to say that 
 Curtiss stoutly insists that his machine is not an in- 
 fringement of the Wright patents, although Judge Hazel 
 evidently thinks differently. 
 
 What the Judge Said. 
 
 In granting the preliminary injunction the judge said: 
 
 ''Defendants claim generally that the difference in 
 
 construction of their apparatus causes the equilibrium or 
 
 lateral balance to be maintained and its aerial movement 
 
 From Aeronautics. 
 
 Basis of the Wright Patents. 
 
 Moving the hand lever F, operates the small upright lever 
 E. This raises the wire I, which connects with wires I, I, run- 
 ning to tops of the end stanchions. The strain depresses, or 
 warps both top and lower planes. Wires H, H, connected as 
 shown by dotted line, operate automatically; as one end of the 
 plane is depressed the other is elevated, as shown in drawing. 
 
 secured upon an entirely different principle from that 
 of complainant ; the defendants' aeroplanes are curved, 
 firmly attached to the stanchions and hence are incapable 
 of twisting or turning in any direction; that the sup- 
 plementary planes or so-called rudders are secured to 
 the forward stanchion at the extreme lateral ends of 
 the planes and are adjusted midway between the upper 
 
208 FLYING MACHINES: 
 
 and lower planes with the margins extending beyond the 
 edges ; that in moving the supplementary planes equal 
 and uniform angles of incidence are presented as distin- 
 guished from fluctuating angles of incidence. Such 
 claimed functional effects, however, are strongly con- 
 tradicted by the expert witness for complainant. 
 
 Similar to Plan of Wrights. 
 
 "Upon this contention it is sufficient to say that the 
 affidavits for the complainant so clearly define the 
 principle of operation of the flying machines in question 
 that I am reasonably satisfied that there is a variableness 
 of the angle of incidence in the machine of defendants 
 which is produced when a supplementary plane on one 
 side is tilted or raised and the other stimultaneously 
 tilted or lowered. I am also satisfied that the rear 
 rudder is turned by the operator to the side having the 
 least angle of incidence and that such turning is done 
 at the time the supplementary planes are raised 
 or depressed to prevent tilting or upsetting the machine. 
 On the papers presented I incline to the view, as already 
 indicated, that the claims of the patent in suit should be 
 broadly construed ; and when given such construction, 
 the elements of the Wright machine are found in defend- 
 ants' machine performing the same functional result. 
 There are dissimilarities in the defendants' structure 
 changes of form and strengthening of parts which may 
 be improvements, but such dissimilarities seem to me to 
 have no bearing upon the means adopted to preserve the 
 equilibrium, which means are the equivalent of the claims 
 in suit and attain an identical result. 
 
 Variance From Patent Immaterial. 
 
 "Defendants further contend that the curved or arched 
 surfaces of the Wright aeroplanes in commercial use are 
 
 
 
CONSTRUCTION AND OPERATION 209 
 
 departures from the patent, which describes 'substan- 
 tially flat surfaces/ and that such a construction would 
 be wholly impracticable. The drawing, Fig. 3, however, 
 attached to the specification, shows a curved line inward 
 of the aeroplane with straight lateral edges, and con- 
 sidering such drawing with the terminology of the spec- 
 ification, the slight arching of the surface is not thought 
 a material departure ; at any rate, the patent in issue 
 does not belong to the class of patents which requires 
 narrowing to the details of construction." 
 
 "June Bug" First Infringement. 
 
 Referring to the matter of priority, the judge said: 
 "Indeed, no one interfered with the rights of the pat- 
 entees by constructing machines similar to theirs until 
 in July, 1908, when Curtiss exhibited a flying machine 
 which he called the 'J une Bug.' He was immediately 
 notified by the patentees that such machine with its 
 movable surfaces at the tips of wings infringed the pat- 
 ent in suit, and he replied that he did not intend to pub- 
 licly exhibit the machine for profit, but merely was en- 
 gaged in exhibiting it for scientific purposes as a member 
 of the Aerial Experiment Association. To this the pat- 
 entees did not object. Subsequently, however, the ma- 
 chine, with supplementary planes placed midway between 
 the upper and lower aeroplanes, was publicly exhibited 
 by the defendant corporation and used by Curtiss in 
 aerial flights for prizes and emoluments. It further ap- 
 pears that the defendants now threaten to continue such 
 use for gain and profit, and to engage in the manufacture 
 and sale of such infringing machines, thereby becoming 
 an active rival of complainant in the business of con- 
 structing flying machines embodying the claims in suit, 
 but such use of the infringing machines it is the duty 
 of this court, on the papers presented, to enjoin. 
 
210 FLYING MACHINES: 
 
 "The requirements in patent causes for the issuance 
 of an injunction pendente lite the validity of the pat- 
 ent, general acquiescence by the public and infringement 
 by the defendants are so reasonably clear that I believe 
 if not probable the complainant may succeed at final 
 hearing, and therefore, status quo should be pre- 
 served and a preliminary injunction granted. 
 
 "So ordered." 
 
 Points Claimed By Curtiss. 
 
 That the Herring-Curtiss Co. will appeal is a cer- 
 tainty. Mr. Emerson R. Newell, counsel for the com- 
 pany, states its case as follows : 
 
 "The Curtiss machine has two main supporting sur- 
 faces, both of which' are curved * * * and are absolutely 
 rigid at all times and cannot be moved, warped or dis- 
 torted in any manner. The front horizontal rudder is 
 used for the steering up or down, and the rear vertical 
 rudder is used only for steering to the right or left, in 
 the same manner as a boat is steered by its rudder. The 
 machine is provided at the rear with a fixed horizontal 
 surface, which is not present in the machine of the pat- 
 ent, and which has a distinct advantage in the operation 
 of defendants' machine, as will be hereafter discussed. 
 
 Does Not Warp Main Surface. 
 
 "Defendants' machine does not use the warping of the 
 main supporting surfaces in restoring the lateral equilib- 
 rium, but has two comparatively small pivoted balanc- 
 ing surfaces or rudders. When one end of the machine 
 is tipped up or down from the normal, these planes may 
 be thrown in opposite directions by the operator, and 
 so steer each end of the machine up or down to its 
 normal level, at which time tension upon them is re- 
 leased and they are moved back by the pressure of the 
 wind to their normal position. 
 
CONSTRUCTION AND OPERATION 211 
 
 Rudder Used Only For Steering. 
 
 "When defendants' balancing surfaces are moved they 
 present equal angles of incidence to the normal rush 
 of air and equal resistances, at each side of the machine, 
 and there is therefore no tendency to turn around a 
 vertical axis as is the case of the machine of the patent, 
 consequently no reason or necessity for turning the ver- 
 tical rear rudder in defendants' machine to counteract any 
 such turning tendency. At any rate, whatever may be 
 the theories in regard to this matter, the fact is that 
 the operator of defendants' machine does not at any 
 time turn his vertical rudder to counteract any turning 
 tendency due to the side balancing surfaces, but only 
 uses it to stear the machine the same as a boat is 
 steered." 
 
 Aero Club Recognizes .Wrights. 
 
 The Aero Club of America has officially recognized 
 the Wright patents. This course was taken following a 
 conference held April Qth, 1910, participated in by Will- 
 iam Wright and Andrew Freedman, representing the 
 Wright Co., and the Aero Club's committee, of Philip 
 T. Dodge, W. W. Miller, L. L. Gillespie, Wm. H. Page 
 and Cortlandt F. Bishop. 
 
 At this meeting arrangements were made by which 
 the Aero Club recognizes the Wright patents and will' 
 not give its saction to any open meet where the pro- 
 moters thereof have not secured a license from the 
 Wright Company 
 
 The substance of the agreement w r as that the Aero 
 Club of America recognizes the rights of the owners of 
 the Wright patents under the decisions of the Federal 
 courts and refuses to countenance the infringement of 
 those patents as long as these decisions remain in force. 
 
 In the meantime, in order to encourage aviation, both 
 at home and abroad, and in order to permit foreign 
 
212 FLYING MACHINES: 
 
 aviators to take part in aviation contests in this country 
 it was agreed that the Aero Club of America, as the 
 American representative of the International Aeronautic 
 Federation, should approve only such public contests 
 as may be licensed by the Wright Company and that 
 the Wright Company, on the other hand, should en- 
 courage the holding of open meets or contests where- 
 ever approved as aforesaid by the Aero Club of America 
 by granting licenses to promoters who make satisfactory 
 arrangements with the company for its compensation 
 for the use of its patents. At such licensed meet any 
 machine of any make may participate freely without 
 securing any further license or permit. The details and 
 terms of all meets will be arranged by the committee 
 having in charge the interests of both organizations. 
 
CHAPTER XXIV. 
 
 HINTS ON PROPELLER CONSTRUCTION. 
 
 Every professional aviator has his own ideas as to the 
 design of the propeller, one of the most important fea- 
 tures of flying-machine construction. While in many 
 instances the propeller, at a casual glance, may appear 
 to be identical, close inspection will develop the fact that 
 in nearly every case some individual idea of the designer 
 has been incorporated. Thus, two propellers of the two- 
 bladed variety, while of the same general size as to 
 length and width of blade, will vary greatly as to pitch 
 and "twist" or curvature. 
 
 What the Designers Seek. 
 
 Every designer is seeking for the same result the 
 securing of the greatest possible thrust, or air displace- 
 ment, with the least possible energy. 
 
 The angles of any screw propeller blade having a 
 uniform or true pitch change gradually for every in- 
 creased diameter. In order to give a reasonably clear 
 explanation, it will be well to review in a primary way 
 some of the definitions or terms used in connection with 
 and applied to screw propellers. 
 
 Terms in General Use. 
 
 Pitch. The term "pitch," as applied to a screw pro- 
 peller, is the theoretical distance through which it would 
 travel without slip in one revolution, and as applied to 
 a propeller blade it is the angle at which the blades are 
 set so as to enable them to travel in a spiral path through 
 
 213 
 
214 FLYING MACHINES: 
 
 a fixed distance theoretically without slip in one revolu- 
 tion. 
 
 Pitch speed. The term "pitch speed" of a screw pro- 
 peller is the speed in feet multiplied by the number of 
 revolutions it is caused to make in one minute of time. 
 If a screw propeller is revolved 600 times per minute, 
 and if its pitch is 7 ft., then the pitch speed of such a 
 propeller would be 7x600 revolutions, or 4200 ft. per 
 minute. 
 
 Uniform pitch. A true pitch screw propeller is one 
 having its blades formed in such a manner as to enable 
 all of its useful portions, from the portion nearest the 
 hub to its outer portion, to travel at a uniform pitch 
 speed. Or, in other words, the pitch is uniform when the 
 projected area of the blade is parallel along its full 
 length and at the same time representing a true sector 
 of a circle. 
 
 All screw propellers having a pitch equal to their 
 diameters have the same angle for their blades at their 
 largest diameter. 
 
 When Pitch Is Not Uniform. 
 
 A screw propeller not having a uniform pitch, but 
 having the same angle for all portions of its blades, or 
 some arbitrary angle not a true pitch, is distinguished 
 from one having a true pitch in the variation of the pitch 
 speeds that the various portions of its blades are forced 
 to travel through while traveling at its maximum pitch 
 speed. 
 
 On this subject Mr. R. W. Jamieson says in Aeronau- 
 tics: 
 
 "Take for example an 8-foot screw propeller having an 
 8-foot pitch at its largest diameter. If the angle is the 
 same throughout its entire blade length, then all the por- 
 ions of its blades approaching the hub from its outer por- 
 
CONSTRUCTION AND OPERATION 215 
 
 tion would have a gradually decreasing pitch. The 2-foot 
 portion would have a 2-foot pitch ; the 3-foot portion a 3- 
 foot pitch, and so on to the 8-foot portion which would 
 have an 8-foot pitch. When this form of propeller is 
 caused to revolve, say 500 r.p.m., the 8-foot portion would 
 have a calculated pitch speed of 8 feet by 500 revolutions, 
 or 4,000 feet per min. ; while the 2-foot portion would 
 have a calculated pitch speed of 500 revolutions by 2 feet, 
 or 1,000 feet per minute. 
 
 Effect of Non-Uniformity. 
 
 "Now, as all of the portions of this type of screw pro- 
 peller must travel at some pitch speed, which must have 
 for its maximum a pitch speed in feet below the calcu- 
 lated pitch speed of the largest diameter, it follows that 
 some portions of its blades would perform useful work 
 while the action of the other portions would be negative 
 resisting the forward motion of the portions having a 
 greater pitch speed. The portions having a pitch speed 
 below that at which the screw is traveling cease to per- 
 form useful work after their pitch speed has been ex- 
 ceeded by the portions having a larger diameter and a 
 greater pitch speed. 
 
 "We might compare the larger and smaller diameter 
 portions of this form of screw propeller, to two power- 
 driven vessels connected with a line, one capable of trav- 
 eling 20 miles per hour, the other 10 miles per hour. It 
 can be readily understood that the boat capable of trav- 
 eling 10 miles per hour would have no useful effect to 
 help the one traveling 20 miles per hour, as its action 
 would be such as to impose a dead load upon the latter's 
 progress." 
 
 The term "slip," as applied to a screw propeller, is the 
 distance between its calculated pitch speed and the actual 
 
216 FLYING MACHINES: 
 
 distance it travels through under load, depending upon 
 the efficiency and proportion of its blades and the amount 
 of load it has to carry. 
 
 The action of a screw propeller while performing use- 
 ful work might be compared to a nut traveling on a 
 threaded bolt ; little resistance is offered to its forward 
 motion while it spins freely without load, but give it a 
 load to carry ; then it will take more power to keep up its 
 speed ; if too great a load is applied the thread will strip, 
 and so it is with a screw propeller gliding spirally on the 
 air. A propeller traveling without load on to new air 
 might be compared to the nut traveling freely on the bolt. 
 It would consume but little power and it would travel at 
 nearly its calculated pitch speed, but give it w r ork to do 
 and then it will take power to drive it. 
 
 There is a reaction caused from the propeller projecting 
 air backward when it slips, which, together with the sup- 
 porting effect of the blades, combine to produce useful 
 work or pull on the object to be carried. 
 
 A screw propeller working under load approaches more 
 closely to its maximum efficiency as it carries its load 
 with a minimum amount of slip, or nearing its calculated 
 pitch speed. 
 
 Why Blades Are Curved. 
 
 It has been pointed out by experiment that certain 
 forms of curved surfaces as applied to aeroplanes will lift 
 more per horse power, per unit of square foot, while on 
 the other hand it has been shown that a flat surface will 
 lift more per horse power, but requires more area of sur- 
 face to do it. 
 
 As a true pitch screw propeller is virtually a rotating 
 aeroplane, a curved surface may be advantageously em- 
 ployed when the limit of size prevents using large plane 
 surfaces for the blades. 
 
 Care should be exercised in keeping the chord of any 
 
CONSTRUCTION AND OPERATION 217 
 
 curve to be used for the blades at the proper pitch angle, 
 and in all cases propeller blades should be made rigid so 
 as to preserve the true angle and not be distorted by 
 centrifugal force or from any other cause, as flexibility 
 will seriously affect their pitch speed and otherwise affect 
 their efficiency. 
 
 How to Determine Angle. 
 
 To find the angle for the proper pitch at any point in 
 the diameter of a propeller, determine the circumference 
 by multiplying the diameter by 3.1416, which represent 
 by drawing a line to scale in feet. At the end of this line 
 draw another line to represent the desired pitch in feet. 
 Then draw a line from the point representing the desired 
 pitch in feet to the beginning of the circumference line. 
 For example: 
 
 If the propeller to be laid out is J feet in diameter, and 
 is to have a 7-foot pitch, the circumference will be 21.99 
 feet. Draw a diagram representing the circumference 
 line and pitch in feet. If this diagram is wrapped around 
 a cylinder the angle line will represent a true thread 7 
 feet in diameter and 7 feet long, and the angle of the 
 thread will be 17^4 degrees. 
 
 Relation of Diameter to Circumference. 
 
 Since the areas of circles decrease as the diameter 
 lessens, it follows that if a propeller is to travel at a uni- 
 form pitch speed, the volume of its blade displacement 
 should decrease as its diameter becomes less, so as to 
 occupy a corresponding relation to the circumferences of 
 larger diameters, and at the same time the projected 
 area of the blade must be parallel along its full length 
 and should represent a true sector of a circle. 
 
 Let us suppose a 7-foot circle to be divided into 20 
 sectors, one of which represents a propeller blade. If the 
 pitch is to be 7 feet, then the greatest depth of the angle 
 
218 FLYING MACHINES: 
 
 would be 1/20 part of the pitch, or 4 2/10 inch. If the 
 line representing the greatest depth of the angle is kept 
 the same width as it approaches the hub, the pitch will 
 be uniform. If the blade is set at an angle so its pro- 
 jected area is 1/20 part of the pitch, and if it is moved 
 through 20 divisions for one revolution, it would have a 
 travel of 7 feet. 
 
CHAPTER XXV. 
 
 GLOSSARY OF AERONAUTICAL TERMS. 
 
 Aerodrome. Literally a machine that runs in the air. 
 
 Aerofoil. The advancing transverse section of an aero- 
 plane. 
 
 Aeroplane. A flying machine of the glider pattern, 
 used in centra-distinction to a dirigible balloon. 
 
 Aeronaut. A person who travels in the air. 
 
 Aerostat. A machine sustaining weight in the air. A 
 balloon is an aerostat. 
 
 Aerostatic. Pertaining to suspension in the air ; the 
 art of aerial navigation. 
 
 Ailerons. Small stabilizing planes attached to the main 
 planes to assist in preserving equilibrium. 
 
 Angle of Incidence. Angle formed by making compar- 
 ison with a perpendicular line or body. 
 
 Angle of Inclination. Angle at which a flying machine 
 rises. This angle, like that of incidence, is obtained 
 by comparison with an upright, or perpendicular line. 
 
 Auxiliary Planes. Minor plane surfaces, used in con- 
 junction with the main planes for stabilizing purposes. 
 
 Biplane. A flying-machine of the glider type with two 
 surface planes. 
 
 Blade Twist. The angle of twist or curvature on a 
 propeller blade. 
 
 Cambered. Curve or arch in plane, or wing from port 
 to starboard. 
 
 Chassis. The under framework of a flying machine ; the 
 framework of the lower plane. 
 
 219 
 
220 FLYING MACHINES: 
 
 Control. System by which the rudders and stabilizing 
 planes are manipulated. 
 
 Dihedral. Having two sides and set at an angle, like 
 dihedral planes, or dihedral propeller blades. 
 
 Dirigible. Obedient to a rudder; something that may 
 be steered or directed. 
 
 Helicopter. Flying machine the lifting power of which 
 is furnished by vertical propellers. 
 
 Lateral Curvature. Parabolic form in a transverse di- 
 rection. 
 
 Lateral Equilibrium or Stability. Maintenance of the 
 machine on an even keel transversely. If the lateral 
 equilibrium is perfect the extreme ends of the ma- 
 chine will be on a dead level. 
 
 Longitudinal Equilibrium or Stability. Maintenance of 
 the machine on an even keel from front to rear. 
 
 Monoplane. Flying machine with one supporting, or 
 surface plane. 
 
 Multiplane. Flying machine with more than three sur- 
 face planes. 
 
 Ornithopter. Flying machine with movable bird-like 
 wings. 
 
 ParaboHc Curves. Having the form of a parabola a 
 conic section. 
 
 Pitch of Propeller Blade. See "Twist." 
 
 Ribs. The pieces over which the cloth covering is 
 stretched. 
 
 Spread. The distance from end to end of the main sur- 
 face ; the transverse dimension. 
 
 Stanchions. Upright pieces connecting the upper and 
 lower frames. 
 
 Struts. The pieces which hold together longitudinally 
 the main frame beams. 
 
 Superposed. Placed one over another. 
 
CONSTRUCTION AND OPERATION 221 
 
 Surface Area. The amount of cloth-covered supporting 
 surface which furnishes the sustaining quality. 
 
 Sustentation. Suspension in the air. Power of sus- 
 tentation ; the quality of sustaining a weight in the air. 
 
 Triplane. Flying machine with three surface planes. 
 
 Thrust of Propeller. Power with which the blades dis- 
 place the air. 
 
 Width. The distance from the front to the rear edge 
 of a flying machine. 
 
 Wind Pressure. The force exerted by the wind when 
 a body is moving against it. There is always more 
 or less wind pressure, even in a calm. 
 
 Wing Tips. The extreme ends of the main surface 
 planes. Sometimes these are movable parts of the 
 main planes, and sometimes separate auxiliary planes. 
 
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 AUTOMOBILE DRIVING SE,LF.TAUGHT=.By Thomas H. Russell. 
 M. E. LL. D., Former Edito 1 " of Modern Machinery, Editor of the American Cyclo- 
 pedia of the Automobile, Author of, the History of the Automobile, Automobile Motors 
 and Mechanism, Ignition. Timing and Valve Setting, Motor Boats: Construction and 
 Operation, etc. 230 pages, liberally illustrated, round corners, pocket size, red edges. 
 An exhaustive treatise on the operation, management and care of fylotor Cars. 
 Handling the car on the road under all conditions, making repairs, and locating faults 
 are treated in a thorough manner. The hints on management of cars would be worth 
 many times the price to beginners. Price, Flexible Leather, $1.50. Cloth, $1.00 
 AUTOMOBILE MOTORS AND MECHANISM. -By Thomas H. Russell* 
 M. E. LL. D., Author of Automobile Driving Self-Taught. Ignition, Timing and 
 Valve Setting. Motor Boats: Constmction and Operation, etc. 265 pages, round cor- 
 ners, red edges, pocket size, fully illustrated. A practical illustrated treatise on the 
 power plant and motive parts of the modern motor car, for owners, operators, re- 
 pairmen, and intending motorists. Price, Flexible Leather, $1.50. Cloth, $1.00 
 IGNITION. TIMING AND VALVE. SETTING=-By Thomas H. Russell. 
 M. E.. LL. D., Author of Automobile Motors and Mechanism. Automobile Driving 
 Self-Taught. Motor Boats: Construction and Operation, etc. Fully illustrated, 225 pages, 
 round corners, pocket size, red edges. A comprehensive illustrated manual for self- 
 instruction for automobile owners, repairmen and all interested in motoring. 
 
 Price, Flexible Leather, $1.50 Cloth, $1.00 
 
 MOTOR BOATS: CONSTRUCTION AND OPERATIONBy Thomas 
 H. Russell. M. E.. LL. D., Editor of The American Cyclopedia of tin Automobile, 
 Author of The History of the Automobile. Automobile Driving belf-Taught. Automobile 
 Motors and Mechanism. Ignition. Timing and Valve Setting, etc. 300 pages. An illus- 
 trated manual for motor boat, launch and yacht owners, operators of marine gasolene 
 engines and amateur boat builders. Intended principally for the man who is not a 
 mechanic. Its purpose is to provide a compendious guide to the design, construction, 
 installation and operation of marine motors and to the design and construction of 
 
 motor boats. Price, Flexible Leather, 01.50 Cloth, $1.00 
 
 A B C OF THE MOTORCYCLE==By W. J. Jackman, M. E. Authorof 
 Facts for Motorists. Crushed Stone and its Uses, etc. Former Editor of the Chicago Daily 
 Journal. Liberally illustrated, 250 pages, round corners, red edges, pocket size. 
 A book of practical information for men who use motorcycles. It describes the mec- 
 hanism and operation of the motorcycle so plainly that any man of average intelli- 
 gence can understand it, regardless of mechanical training. It is the one practical 
 book that really shows you how and should be read by every man who uses a 
 motorcycle. This book shows how you to remedy road troubles almost instantly. 
 
 Price, Flexible Leather, $1.50 Cloth, $1.00 
 
 FLYING MACHINES: CONSTRUCTION AND OPERATION - By 
 W. J. JacKman. M. E. Author of A B C of the Motorcycle, Facts for Motwists, 
 Crushed Stone and Its Uses, etc., and Thomas H. Russell. A. M., M. E. Charter 
 Member of the Aero Club of Illinois, author of History of the Automobile, Motor Boats: 
 Construction and Operation, etc. With introductory chapter by Octave Chanute, 
 C. E.., President of the Aero Club of Illinois. Profusely illustrated, about 250 pages, 
 round corners, red edges, pocket size. Just the book for those who want to know 
 how to construct and operate gliders and Uying machines. It "shows how" in both 
 
 pictures and text. Price, Flexible Leather, $1.50 Cloth, $1.00 
 
 These boohs are written in plain, simple. everyday language, fully 
 illustrated with especially prepared drawings, diagrams and illustra- 
 tions that show you how. Sold by Boohsellers generally, or sent 
 postpaid on receipt of price. 
 
 THE CHARLES C THOMPSON CO.. [Not Inc.] 
 345.549 Wabash Ave., Chicago, U. S. A. 
 
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