RB No. 3E31 NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS WARTIMIi: REPORT ORIGNALLY ISSUED May 19l«-3 as Restricted Bulletin 3E31 IMERGHICY MEASURES FOR INCREASBIG THE RMGE OF FIGHTER AIRPLANES By Robert T. Jones and Joseph W. Wetmore Langley Memorial Aeronautical Laboratory Langley Field, Va. UNIVERSITY OF FLORIDA DOCUMENTS DEPARTMENT 120 MARSTON SCIENCE LIBRARY RO. BOX 11 70 11 GAINESVILLE, FL 32611-7011 USA WASHINGTON NACA WARTIME REPORTS are reprints of papers originaUy issued to provide rapid distribution of advance research results to an authorized group requiring them for the war effort. They were pre- viously held under a security status but are now unclassified. Some of these reports were not tech- nically edited. All have been reproduced without change in order to expedite general distribution. L - 223 Digitized by tlie Internet Arcliive in 2011 witli funding from University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation http://www.archive.org/details/emergencymeasureOOIang [?^y if^fn S bU^'^ -^ UATIOiTAL ADVISORY COMMITTEE FOR AEROHAUTI CS EMERGENCY MEASURES FOR INCREASIITG- THE RANGE OF FIGHTER AIRPLANE? By Robert T. Jones and Joseph W. Weltiorc SUM MARY An analysi" was made to show the relative effect ness of strear.line external fuel tanirs, a fuel tank i the form of a wing mounted in a "biplane position, and auxiliary v:ing pc.nels attached at the v/in,- tips to in crease the scan a? temporary r;. eans for incre^isin^ the rane^e of a f i£:ht er-type airplane. The airplane con- sidered is representative of either an Army or Navy single-engine heavy fighter, Fiip;urei and charts for variou? devices considered show the results of calcul tions of rau,'';e , duiation of flight, and take-off dist for hotn land-oase end carreer operation. 1 V e - n the a nee The resul were the most wa. <: e s t imat ed increase in sp streamline ext of the airplan in the distune "base or a carr would "be incre tations. The in tne efficie gallon. The a to "be carried, the range woul off distance f range due to t crease for a g percent, Incr extra fuel in other modifica t s indicate promising o that 10-foo an of 20 i'e ernal fuel 8 125 to ir^ e required i r . vv 1th a s e d 5 5 to tank wing w ncy of the d A e d area w howsvsr , f d thereby h ron a land he tank v." i n i V e n Carrie easing ., h e a streamlin tions to th i that the v/ing-tip extensions f the devices considered. It t tip extensions - that is, nn et - used in conjunction v/ith a tank world increaf^e the range percent without any incrs". se to take off from eithei- a land 5-fooL tip extensions, the range 70 percent, as foiind to airnlane in under the same limi- cause sOj-ne reduction t e r r. s of m i 1 r r. per greater fuel load or a given take-c;"f distance and e increased. For a given take- base, the calculated increase in ould periTiit a g was about 45 pc-rcent. The r take-off would be about 30 range 50 percent by carrying e external tank without any e airplane would require an m- increase of 30 percent in take-off distance from a 1 ^ n i D a .■? e and 3 2 percent f r ^ m a c a i- r i e r . IIiJTRCDUOTIOIT r el a ti on f i ca rang imp a of g e >r e r Tl'ie range of fighter-type airpla ti-"-ely short ■'oecan-se of high span s on t ii p. s p a e available for fuel tions in tbe depi~n of the airpla es v^culd not he a^ceptahle hecatig c n a. r a c t e r i s t i c s t Under cert a i n irment of cth^ r eater inpcrbance - for example, for ferrying purp of gre?,t value to increr^.ee "he ranf^e "by temporary device?, despite r-acrr'.fi ance cha.rac t er i s t i c s , ne ?; i s ordi n a r i 1 y 1 03 ding an d 1 i ari i t a - fr P ermanen t r. d i - n e t a c h i e V e 1 n g e r e Of the CO n B e a u e n t ha t are o r d inar ily c i r c UM g t an c e n , h o w- 09 f: <^ - it '■; ould he of f ic^ht er a i r p 1 a n e s c e f3 in 1 h e r p e r f r m c a. r cos t an wi t ees nak inc in of al s inil the rem './ n s r y i n g t of a ce . S hout i ted. i n g t h r e a p e adding incr ea the e s per f orm ovahle i d e r s b r e pOB ever r r e Cae e ex thp are s ing span gal of t a i; i e a IT. 1 i f; i bl rl :n a s in of t tern t 1 a a a t :i '[, and Ion enp r in^ 1 n c r p a p li e ex \: e r y prohlh ethod? , g the ts h e e e r. e t al ta;:.k 1 w i n _i- a t h e vj :". n n 1 y t h . thereh :ut: of r a 1- y e t t p. on t h e n^ : J. X V de ke ho in r s S p en m ran 1 fu^l 1 V e in-.; si f'n :, d --off di d s CO ii s t he s h a, . Ai; tips, \\r \'f ing a r the ef Such ar 3 i n r, a r i g i n a 1 ta re I; ap th hi ea f i ea tt w la ay b p c h 'c nks hub cnl a s e in t a i^ e i n c y. e a n e t a n c '? , h av e t T, e 3 p e n t i a e of a n a i r e r K e t b d c n. h a, s t h e for take--o ciency in t night he a a h e d in pi i n r 3 , . X n p d tne ■off ne 0. a n .■-" e hern -ug- 11 TT in f il to on ^rj -L Rt3 ad va noage f f h' at or: r. s of dd ed in ac e of the Do t erminat i c n of the r.-.oi3t exped PE-nd on a numher of factors outside present in^- e pt igat i on , such as pilot available for take-off, and struciiar The following anM]ysi'? is intended t it-on of the suggested methodr' en the tainahle range, flying time required tances frcn either a land oase o:- a Gulations vere made for an airplane of which may he con;!idered represent Arr.y or ITavy single-engine heavy fi^^: ient bhy one al c o p r ha« , an c; a r r bhe at iv hter fiel u r a ?i :i r, 1 ir- d ta i e r , c h a r e of h :1 ' : i d f t ^ e , a r d.'r at i e a c c f r.!a~i ke-o±f Th e a c t e r ?- e i •'" h e 11 de- he pa n r; , np ^i r - inu -t; a t • dis- cal- sties r an AIJALYSIG Airpl3ne.- The characteristic? of the airplane con- sidered, in the Bnaly sis are; Wing area, square feet 310 Wing span, feet 41 '.vinf! incidence a-igle, degrees 2 Ground anr-'^le ( 1 cngitxidinal ar'i?), dc^reps 13 Empty weight (design grors v/ eight less normpl fuel lord), pounds . . . 11,000 Engine di spl acerent , ou'bic inches 3300 Supercharger t'.-^o -r. t a^e , gear-d"iven Propeller thref--tlp.de, c ens t nnt-sr. eed Pr op ellergsar ratio r;:l MaxiEu;^ speed ct sep level, i.iile<= ,er hour .... 317 Capacity of internal f':pl tank, gallons 300 A GKetcr. of the airplane vith a tank v;ing of 300- gallcn capacity (4-ft chord by 30-ft span} i^ shown in figure 1. In figure 2 the airplane is shewn witn lO-foot v,fing-tip extensions (area increase, appro-:. 30 so ft) and a 300-gallon otrear.line external tank. C alculat i o n of range . - The range '■■'or. calcula^rcd oy the Breguet formula, which takes accoxmt of the coni:inu- 0U3 reduction in pover reouired to operate at " on 3 1 ant 1 i f t - d r a g r a t i , The equation is r> — I ■ ''^ a T,-- v/ .1 s r s E range p Tiiles n - averf.ge propulsive efficiency durin,^ flight average specific fuel consu-nption d.uriii;;; fli?;ht, po-ands per hor aepower-hour L/D lift-5r;',f^ ratio of airplane Iv'^ weight of airplcr.e at tahc-off V/g weirht of airplan--^ v/it."i tankr; enpty Calculation of aer odynar. i c efficiency L/D,- The values of aerodyaami c ef f ici i.;r.cy L/D for u-:' e in the range ecuation were computed from the relation 1_^_07 5 '.v/pY3 — H- 075 Trb-' v.'here f parasite area of airplane W weight of airplrne p mass density of air V true airspeed, tniles per hour "b -, effective 8'oan late spon site wing area coef laye was a fi d di ~t s f i r^ as ne or t f ro iri ng p r e a d. ip e:c of th cient jfor s \i.Ti e d ness e or 1 c n 3 i w 3 r ue to t e n a i e s e F. of the to b r. .t io gin de r utp th on 3 ddi .00 str e t of a J. ati ut t io a i r p 1 p n , t h e v -i 1 u, :> o f f \-j ■ ■_ s c a 1 on of the maxirju-r. speed .and cor re- ef the engine. Inorementc in para zternrl tr.nhs, the tank wing; and re o s t i m a t e d hy d e t e r n i n i n g t h. e v; e as and multiplying "by a nkin-frict reproseatat .i.-'e of a turbulent houn eamline external tanks, the wetted ar hat of an ellipsoid of revolution hav ? and providing the desired volume. cu- the tted ion dary ea ing The drag of r. faired t.?,nk has teon found to bo slifl-'tly 3. ess than that obtained by this metLod. For the normal airplare and tho airplp.ne with vring- tip cxtonsicns, the effective ,span b^ w.ib asauraed to be 90 porce^.t of the actual spnn. For thu tank win^", the effactive span \:as taken as the effrctivs span of tho original airplai:e multiplied by I-Iunk • s span factor; tho value of the factor for the configuration assuncd (fi;"o l) v;a3 taken from reference 1; and the assxinipticn that the lift v/ould be distributed cotweon tho t'yo •-.'■ingG in pro- portion to their respective areas v/as used. Tho curves of L/D against 1 ^ v:hero V.' is the .-^irplane weight vith any fuel lo.-id and 7 is the true airspeed at an altitude of 10,000 f'?ot, are plotted in fig- ure 3(a) for the various modifications of the airplane. The curve for a given airplrne conf igtirat icn is independent cf 1 Of. ding when plot^iyod in this r.annor, Calculf t i on o f e n >? i n e -pr o p e 1 1 'U r efficiency 'o / " - Values of propulsive efficiency r, v/ore coEputed fron full- scale test datwa on a suitable propeller- nacel le combination. Specific fuel consumption C -rav d.^terinined from manufac- turer's performance charts for the engine considered. It was .af.su:r!od that the engine v/as oper^'ting in low blov/cr and subject to the limitations on engine speed and manifold pressure specified for the cruising pov;er condition, [The values of C were increased 5 percent to take account of oil consumption; The maximum value of the rstio ii/C was determined for several values of brake horGepowor n,t each of a number of -•■. ir speeds ; an altitude of 10,000 feet was assur.:edc it v;as found that the maximuir valine of t\/0 at a given airspeed is x'- ac*'t i 'jally u.naffected by considerable variation:-: in pov/er, V'ith the result that a single curve cf -n/C agrins'j true airspeed, given in figure cCb), could be need for all the airplane uoAif i cat i ons co :.^idored, De t e'yp ; nat inn of loading .- The veight of fuel carried was estimated on the basis of 5 pounds per gallon. This value was increased 5 percent to allov fsr oil consur.spt ion. "he v;eight of the streamline external fuel taakf- and tne weight of the tank wing were assumed to be 15/85 of the weight of the fuel the Gank;, aru capable of carryin--:;. The eight of the •.,'ing-tip extensions wa;'= taken as ■'!■ pcundr^, per square foot of area added. The loadings used for the sev- eral modifications of the airplsne that were considered in \r tlie calculations arc given in the follov/ing tati> Cond iti 0! i^ r r. a ± . rpiaue 3 C - g a i 1 r. a -■: t c :;' n a, 1 tank added 5-foot wing tips added 5-foot v-iri,3 tips and 300-|?;allon sztcrna! tank added 10-foot win.^ tip3 aided 10"foot viag tips sn-l SOO-^falloii e:!cturnal tank added i^otal fuel capas ity (gal) SOO 600 300 ;oo 6C0 Supty ; Take-off; vrei^ht i weight i Wx/1- , (ro) \ (ih) I 11,000 i 11,519 -2,830 ' K n Ci ■■> \ 1 'i'x'x j.1 ,U»<, -u.OOO ' 11,155 ; 1C,04 1 1 1^ ° J- O -1- ^' '" { 1 •> / ''? / i T cr o / rj I -; n: '^ Q I ' ' I ! j ' 11,300 j 15,132 i l.,16o 1 I ! i i ' ■ I ll,ol9 -■ 15,392 I 1.3:^4 from "both a 1 various airpl the distance eluded. It \-i that there va computed by t v/as taken as spe ed and t he run distances step intCi^rst the a s surap t i o plan.; takes o height. ?cr qu i r d to r 1 1 cf ■ take-off s wheel would "o airplane v;as f 1 £.' p 3 off s. [!he de roll in g-f r: ion of r. -'k c-off distan w e r Tak e cc •i — C -npu tf; dint a for an c e 3 and ha so r n d a carrier the an3 condit ions. ?or t ho 1 and- hase take- off s, required t clear a 50 -foo t OD str c 1 R --/as in- as R s s Ui-i =3 d tJiat flaps woul d n t h *^ 3 o -I. and s no vjinde The ground — run dis tan ze s '■'' r .; h-3 method of r e f e r G n c e The ta ir r. -off speed 5 percent in excess of t he pov er- cf f sta lling r olling-f r i c t i n c c e f f ici eat , as cG5, Air- v/ c r e e 3 1 i mated frcu: t ne r esul ts of .i tep -hy- ions of t h e a: r-run f 1 i;;ht '0 a 6 -1 >. ha s ed A- n that the lift coefficien t"at v.rhic h the air- ff v-ould D 9 naintained up to t i.'.e 50 -foot the carrie r take-offs, onl y th p \ io ta" ce re- aiu take-o fx spsed v;as cal cula ted 9 2-3 timation peed was cased on the a s s u mpt 1 on th ft th c t a i 1 3 in 2 li t a ct vn. t'l the he equipped deck o •*■ tak 6 "' off. 2he assumed to wit h pa rti al -span thao would he deflect ed 5 0° f or ca r r i e r takc- ck-v/ind ve 1 c i 1 7 '■ ■■ as t aken a s 25 knotn V nd the ion c -J f f i .■>-;,■ t; t- •- c '"1 ^ -.• ^ J ^ J t.v O V. * 02. The me th od of refer ence 2 v/rs used for the c rlcnlr-.ti on of the take-off dis- t an c e s . earn airplane in the slipstream vas ass'imed proportion to the inc rears in dyii.iniic pressure in the siip- strea.-n<, It v/as aoSi-Tsl that the induced drag associated with the lift incrament due to the slipstream v/ould ho the same as thojgh this lift increment v.'ere ottained vrith a flap having a span eq^uril to the slipstroac diarotor. The effects of ground interference on the lift-curve slope and induced draf;; v;ere ostiinated on the "basis cf vricsslEhcrger ' i adaptation of "biplane theory (refercnco 4)^ riSSULIS AlVJ LIS3USSI0:T C hart for r an^e and tak^-cf f distrncq.- A chart, from which tne range, mean speed or deration of flight, and take- off disti^ncas from a land ba^e or a carrier nay be estinated fjr 8,ny of the cases considered, hp.s baen conttructei from the results of the ralculct ior.s of range and talce-off dis- tance and is riven in fi;;ure 4, Values of the rangs effi- ciency factor -- ~ arc T)lo';ted in the upper left-hand CD" section of the chart against a variable -peed scale Just belov;. [This plot shOYs lines of constant aean speed sloping to the left v/ith increasing values of the ra-io of take-off vrei^ght t :> cppty ■wsi;:;ht, ^iven on tne diagonal scale to the right, and therehy takes accov.nt of the fact that the speed corresponding to a givon point on tV j --■ ~ curve u u for a given condition increase's '."ith increasing -./eif-htr Inasmuch as the value of r,/G (fi,:. 3) for a rjiven speed is fotind to be practically inilepandent of loading for the en^^ine-operat in£ conditions assumed, the value corresponding to a givon value of L/D vrill vary s o::ievrhat '/ith loadingo Ths variation, however, is s-aall ar d values of Ti/C for the airspeed corresponding to the average of the full and empty loading for each airplane conaition were therefore used in de t ormininj'; the — — carves, CD In the upper right-hand section of the ch,nrt, curves defining the rslr.tion 'betv/een H .— and V'*. /'.v I'or con- st-^nt va.lue& of range aro 5 lotted, The- l^v;er p.Tt of the cl-;?rt ?ho'-/s the -"ariation '.'ith '»/a-/W. of tako-off distance from a land "base or a carrier for the varicjis airpla,ne configurations. [Che method of using the chart is indioa.ted in fi,:;- uro 4 hy the dashed lines dra^wn hetv/oon the cn-iall circles on the curves ard sca-les. Ths case illustrated is that of estimating the n;a.xiir.um ranf;e and duration of flight of the normal airplane for v;hich the take-off dir^tance from a la.nd "base is limited to SC'CO feet. A line iri dra'-rn Terticr.lly from thj .?500~foot point on the l-m-l- Dase ta.ke-off curve for the norn;.al airplane through the '»'''t/'''e scalo a,nd up to the ran,2;o section. Another lins is drav;n horizontally -% T. fro ni the ^o r ak f t h e p r -p =: r -^ — c ■■.-■ r v e to i n t i; r s 3 c t t ^^ e vertical Ijne. (It rill hi- no'-.ed t.bat the value of ^ — C D is hetween the peaks cf the iic-o::t ernal-t ank and the L-CO- gallon-ext crnal-tank curves to take account of the f ac !; that c^n int errnev i at J extornai-tank size is re'q_uired for the ca-se assumed in the orcamplec) ""."ho intersection of the horizontal and vert i '^.■■■.1 lincis .'^ives the v.al'oe of maximum range - about .?050 Hiile': for the e:.'a,mple. In order to eetiraate the r:e an velocity, a vertical line is drawn do'/n fro;u the poinb c or re r-pondi n--'' t the v~lue of -^ — used in determining the range. The point of intersection of this line with a hcrizcntal line drav/n frosi the pr e-ri ously e st.ahlishod p.-. int on the Vv'^/V.'^ scale gives the moan speed of the flight - about 203 miles per liour for the exar.plo. The duration of the flight is £:iven "by dividing the range by the T.ean sp^ed and is found to he about J, 05 hours. The same procedure v;culd he followed for tJis •-ar.e of take- off from a carrier, using the carrier take --off curves in- stead of the 1 -aid- base curve o. ligures 5 and 6 ha^o been rn-spr.red from the cha^^t in figure 4 to provide a more direct comparison of the various means for increasing the range. figure 5 sho.rs the minirnum take-off distances and the corresponding duration of fli,?-ht plotted against range^ Piguro fi giv<:s .the variation cf take-off disla}iCe3 with range when the duration of flight for a gi^ron range is the same for all caries as that for the original airplane operating at ma"-i.';ium efficiency. Stronirlino ex t_ern^ 1 tank.- In aci f i t ha t, tv i n c r 3 a s i n g t he fuel cap t7 SOO to 600 gallons through the use of tan k, the maxinum r an g e '•; u 1 d be incr to ,^eoc n lies or a bout 80 percen 1/ • n from ? Ip. nd base v/ould be increa s ed J. 2940 foet cr about 55 p .?rcent , Froa off d i 3 1 a nee wQ-uld be i n c r e a 3 e d fro U aboiit 69 pcrc ent . 'J?he extent to v h ic tal- o-off distance from a land ba se v;c dep ends , of c Ti r s s t en the size of ai For c c r r i er operat ion, hovrever , any rTt tak 3-Cff di stance '■/ u 1 d probably bs a ruro 5 it is shown of t h e a i r p 1 an e fro ii a streamline external eased froa about 1450 he t ak e - o f f distance rom 2150 feet to a carrier, the fcake- 50 8 to 500 feet or h a.n increase in uld be acceptable rfield available, aterial increase in serious disadvantage. iTank v;in.^- -- T h ? tan!: means of providing redded w airplane lacj take off v/ith long-ran.^e missions fjT.± , a space for this extra fuel, probably be mounted as the shov/n in figure 1, V;ith s theoretically possible to the airplane to some exten would be required for th.e unduly complicate the stru poses of this analysis;, it of aspect ratio 5 v;ith an a fuel capacity of 300 ^^al practicable oase. -his ar the effective span of the comparison with tne origin hence the parasite-drag in f u:-"thernore , is about twic equal volume. As a result is soinewhat less efficient line external tank. (S.e win-:; is essentially a temporary ing area in order that the a greater fuel load for certain t the sane time, provides tank This auniliary win^: would upper Mills: of a biplane as uoh an arrangement, it would bs increase the effective span of t but the high aspect ratio that au" ilia ry w ing w c ul d pro b ah ly ctural problems. For the pur- was assumed t;;at a tank vfing area of 80 square feet and Ions vrould represent a reasonably rangenent entails a reduction in combination of about 2 percent in al airplane. The wetted area and crease d\;e to the ta.nk wing, e that of a oocy cf revolution of , the airplane v:ith the tank v/ing hr.n the a.irplane v/ith s t r e am- - i< and ) as a gall incr the oper 2100 tanc load be i tive I'ao e r educ on fue ease i greate ation. ncreas nes s 1 1 ec ticn 1 lo n r r, r f u the or or t ga ed t f th 1 ad ng el ■L U rb he 11 n an ou on 17 th r an 1h-' for -oad k w; i. A rig So irr. 13 reduced efficiency shov;s in figure 5 ge from 2600 to 2440 miles with a 600- tank v.'ing doeS; hovrevcr, give an a given take-off dj stance, because of that can be carried- lor lar.d-b.ai?e ing increases the range from 1440 to 5 percent for the t- am 3 take-off dir.- inal airplanr; v/ith the normal full fuel For carrier operation j the ra,nge would miles or aooi^.t 20 percent, 'ihe effec- wmg o: carrier operat.'.on m compariso; 10 witli that for lp.nd-oa,se oper-ition i? radiiced hocause tho flap en the original win,!?; is used for the carrier take-'Offs and the 8,dd3d ving area due to the tank v/in^ does nct^ in this c a proportionately increase the take-of: If t , Jft^in ^_b i'3 extensions , ~ Increasing the span c f an a i r- pla^e, other things remaining equa,l, will pr oport ioiiat ely increa,se the maximum range attainable v/ith. a given fuel load, This fact suggests the use of aa-'-iliary panels ; attached to the vin^' tipc in 'place of the renovahle ti^D fairings (see fig. 3), as a promising means for increasing the r a.n k- e „ speeds c V. 1 d the»ir. for 1 flight b e nee taper tho sa foil s struct w i t h u Inasmucn as po bo c ii •; t r u muc ch T a a i , If. 3Sfi in •no ect UT',: t n ce . t ir c on'; hec ngs ajor ary, th3 time ion;.: hy a t ?. r tip j:u t h e the greatest ran ^e is attained at moderate ssihl-^ that these tbicporary tip exte.nsi on s ctod of fairly li.«;.ht -.■■/ood or plastico Tur- e the '•■ring of a fifjhter airplane is designed h greater than thoG.-i oneountercd in level anges in tha aain v;ing structure might not t is suggested that, by using a greater :;:' tensions as sho^^/n in figure 2 r.n-l at ital'ly increasing the camber of the air- he gust loais impciod on the main 'virg tip oztensions can be considerably reduced 3 a 1 i ■ if -p, G t i n ,ir •an,?. the t a> e - f f T hr-. tip ext 3 n s i n s v'ould CO r. z 1 d. e 1 a t e r a 1 mane uverability of tho a irp la c n s i d e red. it i 5 estim a t e d that tip span ( over-a 11 s pan inc r e a s e d f r on 41 crease the m a:cimun valu e of the t i-p h attainable \-i ith the ail erono abo ut'sO believ ed tha t th i c 1 3 ;3 in CO n t r ol ef be too ser io us f r t h e maneuvers whic in g 1 ong-ra ,ii g e flight. Flight tests moment f i -1 ^ rt i .a i an ai rp lane abou a:: is c an b e at 1 3 a s t d ublod v;it hout 1 at era 1 man J uver ability ; aocordi "r;3y: i n e r t i a due to t he tip extension 3 sho- effect on t h ,e re 3 p n 3 e t - •', i 1 e r n con T he rel ativ ely lo-r stabilit y tha ist ic of fig h t e r -type a irp lanes -;ould f atigu e n a Ion g-range flight c ^he rably reduce t n e , ]? o r the f ;, e :c t e n s i n s of to 61 ft) v'ou elix angle pL p e r c n t . It f ec ti venesD '•ro h might be reo have '.;hc'':n t'- t its longitud ir 10 Id /2 is ui at in .-natcrially affe- t ]■- e added m o n e '■ ulf'. have no not. trol. _ lane -foot d;- d not red t h e ai tin"; t of c ■-'■::t le tend to increaso emporary d-jvices normally character- pilot u ? e d for increasing thj range shoul'db* t he ref oro be designed, in- sofar as possible, to improve the stability,. Increased longitudinal stability could be obtained by pro/iaing svccp- 11 ■faaok in the -'/irig-tip oxtensione or ty properly disposing the ftiel load carried in external tanks. Wing-tip exten- sions :--.i£:ht oe dasiftned with sufficient dihedral angle to iinprove spiral staTjility, if necessary, in order that the with rudder alone in snooth air. CM pilot could fly C\J 1 l-H Shi use of conjunct ion v;it be the raost eff the ran^e attai: the efficiency ures 3 and 4, v fuel load is gr give a suhstant figure 5, the m of ftiel is shOT w i t h 5- f 1 tip tip V. :-:te:is ion s . take-off distan land "base or a to about 2400 ni extensions and percent with 10- sions, in c on tr effective in in distance frcTi a increased lift- gives a rolativ angle of attack i^ith the tank v ving-tip extensions, either h streaaline external fuel t active of the means consider nahle with fii^iiter airplanes of the airplane increased, a ith the resu.lt that the ranc^ 3a,ter, but also the added \'ri ial improvement in take-off aximum rango of the airplane n to be increased from 3600 extensions i,nd to 3450 mile It is alao sho'-ni that, wit CO of the original airplane carrier, the ran,^-e is increa iles or almost 70 percent wi CO about 3300 miles or betv;c -foot tip extendi on 3. The v/ ast './ith the tank wing, appe creasing the r xnge for a giv ither a land baf;e or a ca.rri curve slope v;ith the wing-ti ely higher ta]:e-off lift for of the carrier take-offs th ing. alone or anks, appe ed for in2 Not onl s shown in G with a g nj7 area wi di sta,nce . with 600 to 3030 mi r. wit.h 10- hout excee from eithe sed frons 1 th 5-fcot en 12 5 and ing-tip ex ?r equally en t ak e - f er because p ext en si o the fixed a "1 is o b t a m ars to reasing y is f ig- iven 11 In f^allons les foot ding r a 440 tip 130 ten- f the ns ined Inasmuch as an ir.crcase in span reduces the airrpaod at v;hich maximum efficiency i :j attained, the time of flight over a given distance will be grsater vith the wing-tip extensions th?.n v;ith the original airplane or ary consideration is the h the least possible fuel s case it represented in be flown is so gv^at as t a.'.y be desirable to fly with the tank v.'in;-^, if the pric; wit ?hi attains en t of a ^iven rang take-off distance. V/hen the distance to load . fi^rur to tax the pilot's endurance, i at spjeds higher tha,n thos^s at occurs, even though a tTreater f ta,nce will be required. Oo.'rip.ar shows that t.he flying cpeed for wing-tip extensions could be increased to the dr.ration of flight for a =i uel load -?,ni ta-ke-off dis- ison of figures 5 and 6 the --ir plane equipped with r an the extent that s the sp.ne as for th( iginal airi)lj.ne w-ithc; seriouoly increasing the ta.ke- a given rrnge or, conversely, vrithout greatly reducing the range attainable for a given take-off distance. off distances for 12 C M C LUD I il G HE KJiR Z S the r w i n .=:»• airpl s i n s c r. J -0. r an g e c r a s lar.d rauf e limit nnzo t ip & a "1 c - th n c t i of t e in a rn e t I'l i 3 c o n s i c ^- j.- a d for t e m p o r a r i 1 v of f ight -u-- ty-pG airplanes, the use of ztension^ appears tho most pro-iising, onsidered, it w.vs optimatod that 10-f at is, an increase ii. spr^n of 20 foet n '"/ith ai. extjrnal fuel tank --rould in he an r piano 125 to 130 p^rcant withou t h 3 d i s t an c e 3 r e q ii i r e d to t a 'r e off f r or a. carrier. With 5-foot tip extons base would he increased £5 to 70 percent, unde at icns. i n c r e a au~il For 1 r-x - uce c r e a. s s t any om ait ions, r the sing iary t ho ten- d in the in- h G r a tha same tnou for loi; or i li!? fue hec he has per ba An nt ed SOO i?r •? 1 ginal b e::t 1 lOf auae i n G r (V e , t h cant, about auxil above fallo f i c i e airp ernt.l d to of th a s a rl . : i n c The 20 p iary v/iui^: of 4-fGot r, hord and 20- foot span the laai.a nin^ and providing tank capacity ns of extra fuel, was sho-.m to ^ive soirev^hat rcy in barns of raileo per gallon than the lana ^"it,,! the e:.;tra fuel carried in a stream- tank, rh.d tank wing would parmit a f^reater be carried for a given take-off distance e .-..ddGd v;ing area, and the ran.^e would thereb ?or a .=:iven tj'ke-off iistanco from a land raare in ranga v;as esti-nated to ba about 45 increase for a given carrier take-off -/ould a r c a n t , Increasing the range 50 percent by carrying extra fuel in streamlint; external tanks without any other modi- fications to tha airplane ■■■ould entail an increase of 20 percent in take-off dist \ce fron a laud base and 32 p;>rcant froi;i a carrier. Selection of tha most uui babble niethcd for a particular application will of covirse depend on other factors bef^ideg the attaiJiable ranr^o and take-off performance, nuch a.s structural problems, pilot endurance, and area avails.bla for '.-ake-o f f , For example; if in, a ii^iven case the duration of fiii-ht i-'ith oxtarnal tank?, alone ic equal to the endurance of the pilot a.nd if the area and the span available for take- off are adoquata, bhare wi] 1 be little advanta^-e in the use c f m ore officii i.-. t m .; t h o d s . Lan,7;lcy Memorial Aarcnautical Laborat or:-^ , iV^ational *i.dvi3ory Committee for Aeronautics, Lan^^^ley Field, Va . IS Hill £ LiivExTC 2j S I 1. ;5. Diohl, Walter 3,' Snf.:inei3i^ing Acrodynamicr . Tho Pwonald Press Co,, 1323, pp. ;^e-40. Eartman, Sdv-in P.; Considerations of the Tfke-Off Protlom. T.r. Ilo - 557, NACA, 19G6. Smolt.. 3. , EJid Ds'.vios, K^ : Sstiication of Increase in Lift due to Slipstream. H. & M, ilo. 1788, British A . P. 19 37. 4. V/iooolshorgir , C,: V/ing Kesiitr.nca near the (^ro-ind, 'f.Ko wo. 77, NACA, 1922. NACA rigs. 1.3 c d n C o w o J3 to c ^ d J3 to NACA Piff. 3 l-TN (\J I ,1 ■lloTBD.1 Pirplarte 300-gal tarilc ;vinf^- added 3-ft wing- tip extensions _^. j "O-ft '..'in.^tip extensions Lift-drag raiio. 0L_ 100 SOD ._! — \ OJ-J Ti'ue airspsad, niph 7"^/^^ (b) __i ; ! j I Ratio c|f propulsive ei:Tric5'ency speciijic fuol consuinbticiij to i j I ! 100 200 300 •True airspeed, mph Figure 3.- Variation v/ith trus airspeed of lift-drap- ratio and ratio of propulsive efficiency to specific fuel consujyption for various modifications of fif:hter airplane. Altit-.de = 10:000 feet. NACA yfC— a'/j fa/ice for i/ar/ot/s /vod/f/6a//o/7s of fighfer a/rp/anS. '/ -^'c uiOOf l/erfjca/ marJfs on raKe-off .jryes c/e/iote 300- ancf600-^i, . ^/ /r IIACA i?3.g. 5 4000 ICOO 2000 -, Figrure 5,- Va.-iatio.i r.ith range of talcaroff distances frora a land taae and a carrier end i\iration of flight for variono modificctio'^s of fighter airplane. Flight at 10;000 feet at ^peei of rnaxiirrjuii n/o l/d for each condition. Vertical marks on cj.rvus of take-off distance arainst range denote take-off distance and ranfre with 300- and SOO-gallon fuel loads. NACA i'lP:. oj I 1-1 3000- -p 'h » CD " ?000 - ,^ Ti f1 d iH •* a ■)j o -H C a) ^ -p '-t D2 ■x> ■H • .— 1 -d fH ^1000- o '.1 1 1) •;) 4>J f) rf }^1 e^ ^ +j '.1 •H -d