FILE COPY NO.· 2-W c I lE

NATIONAL ADVISORY COMMITTEE

FOR AERONAUTICS

REPORT No. 630

A FLIGHT COMPARISON OF CONVENTIONAL

AILERONS ON A RECTANGULAR WING AND

OF CONVENTIONAL AND FLOATING

WING-TIP AILERONS ON A

TAPERED WING

By H. A. SOULE and W. GRACEY

1938

I N GZ 50630

For sale by the Superintendent of Documents, Washingwn, D. C. ... ... ... .. ... - ... .. .. ... - .. Price 10 cents

Subscription price, $3 per year

w , g,

m,

I,

s, /)u;,

0, b,

, . I,

'1,

L,

D,

c,

AERONAUTIC SYMBOLS

1. FUNDAMENTAL AND DERIVED UNITS

Length _ , Time __ Force

Power Speed __ _

Symbol

P \ -

L' llit

meter second_ __ _

l\lC't)'ic

weight of l kilogr~m

horHepower (metric)

{kilometers per hour _ ltl eters per second

I Abbre\"ia­tion

111

S kg

k .p.h. m.p.s.

English

(' lIit

fnot (or mile) __ _ second (or hour) weight of 1 pound __

horsepo\\"er __ miles per hOUL ______ _

feet per second _ _

Abbrevia­tion

ft. (or m i.) sec. (or hr. ) lb.

hp . m.p.h. f.p.s.

2. GE ERAL SYMBOLS

,Yeight=my Standard accekl'ation or grayity = 9. OG6;)

llt 'S~ or ~2.17..jO [t. jsec. 2

W 11 ass=-

9 :-loment of incl'tia= mF (Indicate aXIs of

rndius of gyration k hy proper ubscript.) CoefTicient of yiscosity

v, Kinematic yi eosity p, Densit!, (mass per unit yolume) ,Umdard delli-iity of dry air, 0.12497 kg-m-4_s2 at

1.io () . and 760 mm; or 0.002378 Ib.-ft.-4 sec.2

Specific weight of "standard" air, 1.2255 kg/m3 or 0.07().,)11b. /c li. ft.

3. AERODYNAMIC SYMBOLS

~\..I'ea

Area of wing Gap

pall Chord

~\.spect nltio

True nil' speed

D · 1 1'? ynuIllic pressure=2 P -

Lift, ahsolute coe.fficient C],= ~f q.)

Drag, absolute coefficient, OD= ~f

Profile drag, absolute coefficient O})o=~S

Induced drag, ahsolute coefficient CDi=D t

q

Parasite drag, absolute coefficient ODP=~S

Cross-wind force, absolute coeffiCient Oc= q~

Q, n,

n P-'

J.l.

_\..ngle of setting of wings (relative to thrust line)

Angle of stabilizer setting (relatiye to thrust line)

ResuJ tant mOlllent R esultant angular velocity

Reynolds Number, where l is a linear dimension (e.g., for a model airfoil 3 ill. chord, 100 m.p.h. normal preSSUl'e at 15° C., the cor­re ponding number is 234,000; or for a model of 10 cm chord, 40 m.p.s., the COl'l'csponding number is 274,000)

Center-of-pressure coefficient (ratio of distance of c.p. from leading edge to chord length)

Angle of attack ~\..ngle of downwash Angle of attack, inhnite aspect ratio Angle of attack, induced Angle of attack, a bsoillte (measUl'ed from zero­

lilt position) Fli.ght-path a.ngle

R, Resultant force

74706-39

REPORT No. 630

A FLIGHT COMPARISON OF CONVENTIONAL AILERONS ON A RECTANGULAR WING AND

OF CONVENTIONAL AND FLOATING WING-TIP AILERONS ON A

TAPERED WING

By H. A. SOULE and W. GRACEY

Langley Memorial Aeronautical Laboratory

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

HEADQUARTERS. NAVY BUILDING, W ASHl GTO , D, C,

LABORATORIES, LANGLEY FIELD, VA.

Created by act of Congress approved March 3, 1915, for the supervision and direction of the scientific study of the problems of flight (U. S . Code, Title 50, Sec. 151 ) , Its membership was increased to 15 by act approved March 2, 1929. The members are appointed by the P resident, and serve as such without compensation,

Jo EPH S. AMES, Ph . D., Chairman, Baltimore, Md.

DAVID W , TAYLOR, D . Eng., Vice Chairman, Washington, D.

WILLIS RAY GREGG, Sc. D ., Chairman, Executive Committee, Chief, United States Weather Bureau.

WILLIAM P. MACCRACKEN, J. D., V ice Chairman, Executive Committee,

Washington, D. C. CHARLES G. ABBOT, Sc. D .,

Secretary, Smithsonian Institution. LYMA J. BRIGGS, Ph. D.,

Director, ational Bureau of Standards. ARTHUR B . COOK, Rear Admiral, United States Navy,

Chief, Bureau of Aeronautics, Navy D epartment. HARRY F. GUGGENHEIM, M. A.,

Port Washington, Long Island, N. Y.

SYD EY M. KRAUS, Captain, United States Navy, Bureau of Aeronautics, Navy Department.

CHARLES A. LINDBERGH, LL. D ., New York City.

DENIS MULLIGA ,J. S. D., Director of Air Commerce, Department of Commerce.

AUGUSTI E W. ROBINS, Brigadie:- General, United tates Army,

Chief Materiel Division, Air Corps, Wright Field, Dayton, Ohio.

EDWARD P. WARNER, Sc. D., Greenwich, Conn.

OSCAR WESTOVER, Major General, United States Army, Chief of Air Corps, War Department.

OLt\'ILLE 'WmGHT, Sc. D., Dayton, Ohio.

GEORGE IV. LEWIS, Di1'ecto'l" of Ae1'onautical Research

Jon ' F. VICTORY, Sem'eta1'y

HENRY J. E. REID, Enginee1'-in-Cha1'ge, Langley Memorial Aeronautical La/)o1'at01'!J, Langley Field, Va,

JOHN J. IDE, Technical Assistant in EU1'ope, Paris, France

TECHNICAL COMMITTEES

AERODYNAMICS POWER PLANTS FOR AIRCRAFT AIRCRAFT MATERIALS

AIRCRAFT STRUCTURES AIRCRAFT ACCIDENTS INVENTIO S AND DESIGNS

Co01'dination of R esccL1'ch Need.< of Militn1'!J nnd Civil 11 viation

P1'epa1'ation of R sea1'C!z P1'ograms

Allocotion of P1'o blems

Prevention of Duplication

Conside1'ation of Inventions

LANGLEY MEMORIAL AERO AUTICAL LABORATORY

LANGLEY FIELD. VA.

Unified conduct, for all agencies, of scientific research on the fundamental problems of flight.

OFFICE OF AERO AUTlCAL INTE LLIGE CE

WASHINGTON, D, C.

Collection, classification, compilation, and dissemination of scientific and tech­nical information on aeronautics,

REPORT No. 630

A FLIGHT COMPARISON OF CONVENTIONAL AILERONS ON A RECTANGULAR WING AND OF CONVENTIONAL AND FLOATING WING-TIP AILERONS

ON A TAPERED WING

By IT . A. 0 Lf; and W. GRACEY

SUMMARY

Flight tests comparing the relative effectiveness oj con­ventional ailenns of the ame size on wings of rectangular and tap red plan Jorms were made with a Fairchild 22 airplane. Injormation is included comparing conven­tional and floating wing-tip aile."ons on a tapered wing. The 1'esults showed that the conventional ailerons were somewhat more effective on the tap3red than on the rectan­gular wing. The difference, however, was so mall as to be impercepti ble to the pilots. The floating wing-tip ailer­ons were only half a effective as the conventional ailerons and, jor this rea on, were con idered unsatisfactory.

I TR ODUCTIO

At the reque t of the Materiel Division of the Army Air orp , the J. A. . A. has conducted a eries of iliO'ht te t to compare the relative effectiveness of con­ventional aileron of a given size on wings having rec­tangular and tapered plan form. Earlier wind-tunnel tests are reported in references 1, 2, and 3. The flight te ts were made with two :B aiTChild 22 airplanes. The two wings used in the investigation were of the arne area and span. One had a rectangular plan form

with semicircular tip and the other a taper ratio of 2:1. The conventional ailerons with which these wings were fitted had the same plan-form dimen ion and were arranged during the flight te t to have approxlmfttely the same deflections.

The te ts consisted of the determination of the effec­tivenes of the ftilerons (1 ) for different degrees of deflec­tion at two air speeds, and (2) £01' full deflection at various air speed throughout the peed range of the airplane. The comparison are based on the maximum mea ured rolling acceleration and velocitie , the ob-erved yawing action, and the computed rolling-moment

coefficient. In addition to being fitted with the conventional

aileron, the tapered wing wa equipped with detach­able wing tips that could be replaced by floating win o-­tip aileron. The Doating wing-tip ailerons were also te ted during the ill ve tigation and were compared with th conventional ailerons on th e ame winO'.

AIRPLA ES A D WI GS

The Fairchild 22 airplanes used in the investigation are shown in figures 1 and 2. The rectangular wing, which had the arne plan form as the standard wing (or the F airchild 22 fti.rplanes, had a span of 32 feet 10 inclle , a chord of 5 feet 6 inches, an area of 171 square [' et, and an N. A. . A. 2Rl12 airfoil section. The conventional aileron with which this wing wa fitted had a span of 13 feet 3 ~{6 inches ( 1 percent b/2) and ft chord of 12 inches (1 percent c). They were

FIGURE I.- F airchild 22 a irplane used for tests of conventional ailerons on a rectangular wing.

FIG URE 2.-Fairchild 22 airplane used for tests of conventional ailerons on a tapered wiug.

operated differentially, having a maximum upward deflection of 17° and a downward deflection of go.

The tapered wing (figs. 2 to 5) ha.d the sa.me span and ftrea. as the rectangular winO'. It had a 2:1 taper ratio with a straight trailing edge. The trailing edge wa made straight so thali lihe aerodynamic centers of the tapered and rectangular "'rings could be located at the same point relative to the fu elage while still permit­ting acces to the rear cockpit. In external dimen­sions the tapered wing wa comparable with an 111-

1

2 REPORT NO. 63D-NATIO AL ADVI ORY COMMITTEE FOR Al£RO AUTICS

tern ally braced wing alt.hough it was supported ex­ternally for the tests . The airfoil section varied from an . A. C. A. 2218 section at the root to an . A. C. A. 2209 section at 15 fcct from the axis of symmetry. The

Con ventional a ileron: Floatln9 - tip

aileron "~''F::::::::::::-=-=-=-=~-=~~tt:+=~;:::=~~~ ,.-1.1

: \ : '- - --­De tachable

win g t ip

L ~35 __ '_IO"" __ 1., 'to dihedral

8 ' 0 '

------"-1 - 7' 7"-

Front face of rear propeller 2 ' III:V " - 21 ' 6 " - --. --17"

,/16 2 ' 6Ji6': ~-k~t---.-~,-flange \"~ , ,. I I

" ::----'1'-." 5 0 , "T. 5 ' IlfJ"

Thrust axis ·. I 9' 0 "

~- ,- , 4 ' /OXs "

1

FIGURE 3.- Three-view draw ing showing the installation of the tapered wing on a Fairchild 22 airplane.

30°

/ FIGURE 4.-Section through tapered wing at outboard end of convent ional aileron.

wing tips were rounded. The chord varied from 7 feet 4 inches at the root to 3 feet inches at the 15-foot station.

The conventional ailerons on this wing had the same span and chord and were located in the same position relative to the wing span as were the conventional

ailerons on the rectangular wing. They w 1'C operated differentially and, for the tests, were limited so that the maximwn upward deflection was 18° and the downward deflection 9°. Owing to differences in the aileron-operating mechanism, the maximwn aileron deflections on the tapered wing were obtained with a stick deflection of 14°; whereas, with the rectangular wing, the maximum deflections were obtained with a stick deflection of 20°. The plan view in figure 3, on which the rectangular wing has been drawn in outline, gives a direct comparison of the wings and the conven­tional-aileron installation.

(a) Installat ion of fi xed wing t ip.

(h) Installat ion of fl oating wing-tip aileron.

F IGURE 5.-View of right wing,

For the installation of the floating wing-tip ailerons, the £L;;:ed tips of the tapered wing outboard of the 15-foot station were removed and the conventional ailerons were locked in their neutral position. The floating wing-tip ailerons had a symmetrical . A. . A. 0009 airfoil section at the root. Each aileron had an area of 7.9 square feet and a span of 35 inches; the wing area and the span with the e ailerons were 177 square feet and 35 feet 10 inches, respectively. These aileron were statically balanced about a hinge axis 17 percent back of their leading edges and were permitted to float freely between limiting positions of 40° up and 30° down. The ailerons could be deflected relative to one another to obtain a maximum angular difference of 30° with a stick movement of 24°.

COMPARISON OF AILE RO o A RECTA JGULAR AND A TAPERED WING 3

I J II Air spe ed, fp.s . 0-----9 0

V '" 138

./V " /'

V 0

.~ ./ ---

I I I I

~ Air spee d , fp s

V -- 0----84

'" 138

/' I----

~v 1--

I-- -- -;

I l-

I ."-

V ......-

o..-~ ..Jl' ''-

~ V

----.-if

- -

_0"-...... "-

° ./ V'"

.? V

I !--O-

L" V o o

<r' ° ~..-..-°

~ ~ ~

./' ~

A V

~/ V f-"'0

.,.Q.. V i/ 10'

./ ~ <,,0"

./ Y V lo/

../

U" /- .~ /o..-r- u I

;

I o cO 40 60 80 100 120 o cO 40 60 80 100 120

A ileron defl ection, percent A ileron deflection, percent

FIGURE 6.-Variation o( the maximum rolling velocities and accelerations with deflection of conventional ailerons ou the rectangular wing.

FIGURE 7.- Variation o( the maximum rolling velocities and accelerations with deflection o( conventional ai lerons on the tapered wing.

5 " I

~--~

--° -~

" . ~/ ~- "

° ~ -- V-::.9 -- ---f--

r-- f--I- - __ -~/..-Y -- ''- 1--~~-..-

I- 1--1-- ::;.-- 0 _ 0 -

p6"~b:Cf I I- 1 -~ J.. . I-- _ 0---- onvenlional atlerons on tapered wmg . '--

6- - -- - " "II rec/ongular wIng r--Standard Fairchild CC oilerons ond r-- _. w ing(from reference 4) i-

o I - 8 . .8

--i ~ f--~- -.. .. _ _ - 4

~- .. )g-~ ~ ~ -~

~ ..0--hf" ~- --f--'::::: -

~ ~ -- --- F--' - r---- ---.0 ---.... ---1--.----

- r-' I .I o

80 90 100 //0 120 130 140 ISO Air speed, fp.s

FIGURE S.-Comparison o( the maximum rolling velocities and accelerations with (ull defl ection of conventional ailerons on the rectangular Bnd the tapered wings.

5

AIrspeed, fp.$. 0---83 .. 131

f--f-

I-- - . !.-a-- ..--E

--I--- .,-~---- -<:J

IS>--

1- ~~~ ~~o-1- -

0-_ f-- -c

o

. 8

- .- - 1---

- .---;:-

~ ~

- r .-

v--:~ 1.-0.,..,% --

V~ ~1~ pO - ----I ~ Ar l

o cO 40 60 80 A ile r 0n df'flection, p ercent

FIGURE g.-Variation of the maximum rolling velocities and acceleration;; with deflection of floating wing· tip ailerons on the tapered wing.

- ----- ------ - -----

4 REPORT NO. 63G-NATIONAL ADVI ORY COMMITTEE FOR AERONAUTIC

TESTS AND RE ULTS

With each of the lateral-con trol sy tern ,two cries of Lests were made. In Olle cries, the ailerons were abruptly moved to their maximum den ections c1lll'ing sLeady fligllt at ya,.ioll peeds throughout the flight runge. In tIle oLber cries, the amount the nilerons were moved wa yaried at each of two air peed" one in Lhe high-speed and tll e other in the low- peed range. ]~ach serie of tests was made in gliding flighL for only right deflections of the tick. Records were made of

5 /.0

~ )Iootn)-t) oi/~ro),s_ ~

-- --Conventionol " --r j-

.8 1-___ f-

f,o-- l--...... V,,:;--- -.6

r vroc~ f.-- J...- P--- I <:;:'celeralion .

- j..-"- .....1 ----- --- 1 ~ ,Velocity t .4 ' r- =-0 V;..--- I ~~~I- .-;.0-- I ,0 . -

01 !---- j..J>--r--o I I 0 !----.2 ..0---r-- -, 0 '-A cceleraiion

0 I

0 90 100 110 120 1.30 14 0 o

Air speed, f".p.s. FIGURE IO.-Comparison olLho maximum rollingvolocitiesand accelerat ions with full c1~ nection of the conventional and fl oati ng wing·tip ailerons 00 the tapered winl(.

2 0

, - I-~ i'-- r---.. 6

a ' r-..::.. r--t--...R r--t---. ~

2 0

I or-~ 8

1--I .- -

4 I- --

0 90 100 110 120 130 140

Air speed, fp.s. FIGI ' ItE 11. Variation of the mean fl oating angle of the wing-I ip ailerons with speed.

the initial air speed, Lbe amount the ailerons were moved, and the angular velocities of the airplane in rolling and yawing. These mea urements were up­plemented by pilots ' ob ervations of the control action and control force.

The records were inspected for any lag or luggi hue in the response of the airplane to the aileron movem nt and for the direction of the initial yawing veloci ty. From the records of the rolling velocity, the maximum rate of roll resulting from a given aileron movemen twas directly obtained. The maximum angular acceleration in roll were obtained by differentiation of the rolling­velocity records.

The results of Lhe m a urements arc pre ented in figure 6 to 12. Figures 6 and 7 show the results of the partial-deflection Le ts of the conventional ailerons on the rectangular and tapered wings. The ailerOl1 -defl ection scalcs of thesc ligu l"C arc ba cd on Lhe dificl'­encE'S between the angles of the up and dow n aile rons. For the thrce aileron sy teInS tested in the illYe, tig:l­tion, the aileron deflecti.ons wcre approxima tcly pl'O­pOl·tional to Lhe deflecti.on of the control s tick. Figure

compare the rolling efl'ectivenes for full deflection

.06

.05 G

.01

o

. - i--

.-f--

1--- :-1--- -- --

---- --- 1-=.-

" V - t--- t-- - r--- - -, ,

V V -"'"

f-"""

l- i---- - - - - Conventional oilerons on rectangular wing -- II "" tapered 1/_

-- Flooting-lip " " " " t---- --Standard Fairchild 22 ailerons and I 1 I w1tgtOj re~ere;ce 14} 1 I I

.2 .4 .6 .8 1.0 1.2 Lift coef/'ieien f, CL

F" '!:HE 12. Comparison of tbe rolling-moment cO('mcients of the l al~ra l-control systems tested.

I of the ailerons on the two wings. Also shown in this figm'e are the result of tests of the standard wing for

I the Fairchild 22 airplane. These results were used as a ba i for comparison of the different types of lateral

I c?ntro~ treated in reference 4. Data si~lilar to. those glVen m figures 6 alld for the cOllventlODal aileron are given in figures 9 and 10 for the :[loating wing-tip ailel'on. The mean flofttin g angles of the wing-tip ailerons at various speeds in steady flight are hown in figure 11 .

Figme 12 ha b en prepared to compare the lateral­control sy tems on the basis of the rolling-moment coefficients. The method of computation used in the preparation of this figure involves a correction of the measLll'ed acceleration to zero rftte of roll so that the computed coefficient arc comparable with tho e ob­tained from wind-tunnel test. (See reference 4 for details of method. ) The moments of inertia of the airplane about the X body axe were required for the computations. The moment of inertia of the airplane with tbe rectangular winO" was 707 slug-feet 2; that for the airplane with the tapered wing was 766 slug-feet 2

as flown for tes ts of the conventional aileron and 1,018 slug-feet 2 as flown for the tests of the floating wing-tip ailerons.

COMPARISON OF AILEROI Or A RECTA GULAR AND A TAPERED WI G 5

DISCUS 10 COMPARISON O},' CONVENTION AI. AILERON 0 RE CTANC LAR

AND TAPERED WINGS

The rolling effectivene s of the conventional aileron on Lhe rectangular and tho tapered wings may be com­pared on the ba is of the ulformation given in figures and 12. FiO'ure sh ows that the maxunum rolling accel­erations given by the ailerons on the two wing were ap­proximately the same. The maximum rolling velocities attained were lightly O'reater with the tapered th an with the rectangular winO'. The difference in the roll­ing velocities was of a magnitude sufficient to maIm a difference of 2° to 3° out of approxiInately 25° in the angle of bank attained in 1 se ond after the control movement. This difference wa not discel'llibl to the pilots making the te t , who reported that the l'ollrng cO'ectivene s was equally good with either wing.

The rolling-moment coefficients given in figure 12 al 0 howed that the comrcntional ailerons, when in-taIled on the tapered wing, are omewhat superior to

LIt e same ailerons ,,-hen in t, Ued on the rectangulu.r wing. The impro \'cment va ried sligh tly " 'i tll lifL eoefficient and W<l S of the orei cr of 5 p('J'cent at Lhc high('l' lirt C'oefficients, where norma lly Lbe grealics t difficulty is met in obtaining ad quate control. This result is in agreement with the win J-tunnel ies ts 01' l'cierC ll cc 1 an 1 wa uldicated by an analy is of the two aileron installations made in accordance with the procedure given in reference 3.

With both wings, the aileron showed a normal varia­t ion of ef:fectivene s with control deflection (fig. 6 and 7) . No laO' or sluggi bne s wa noted in tbe re ponse of tho airpla ne to co ntrol movements. Tbe yawing action with uoth win gs wa smn ll and aaver e and wa sligh tly gren tel' with the tltpe l'('(l than witll the rectangu­lin' wing. This l'esulL is a t vari ance with the wind­tllnnel te ts of reference 1 and w.ith the theoretical treatment of reference 3, both of which indicate that the tltpered wing hOlll(l IHLVC the smaller yawing action. No l.lllalysis \\' as IIlH CiP l'ega rding (i1i s cii sC' L'epaney he'­cause t.be .\7a,,-ing actioll \\-as l'elativel.Y small wit,h ei lh l' ,,'iug. 0 compal'i on was mad e o[ Lbe control fo]' es wiLh lhe two di/TE'],E'l1L wiugs he au. (' of th c1iA'erence in Ihe' J1le' chan iC'n l acin-lili age fot' the Iwo conLrol sy t.ems. From Lho fact LI",t lite s t ick [,ntvel for Lhe tap red wing \Va only two-th ird s that foJ' Lhe rectangular wing, it \Va expected that the control force 1'01' the tapered wing would be of t lt e order of one aucl one-half times that for the rectangular wing. The pilot ' reports were in agreement with thi rough analysis.

COMPARISON OF CONVE TIO NAL A D l·'LOATING WI C-TlP AILERONS 0 THE TAPERED WING

A comparison of the rolling effectivenes of the con­ventional and the floating wing-tip ailerons on the tapered wing is given by figures 10 and 12. These results show the floating wing-tip ailerons to be only about one-haH as effective as the conventional ailerons. Observations

made of the control effectiveness at and beyond the stall howed that, although the aU'plane could not be con­

trollecllaterally at the stall with either of the ailerons, some control ffectivenc s wa retained beyond the stall with the floating wing-tip ailerons but not with the conventional ailerons.

Aside from the low rolling effectivene s of the wing­tip ailerons, their behavior wa normal. The re ults of thc partial-deflection te t given in figure 9 show that the variation of control effectivene with aileron deflec­tion is nearly lineal'. 0 lag or luggishn e was recorded or observed by tbe pilot . A smail positive yawing action was noted. The pilots estimated that the stick forces with t he win O'-tip aileron were ahou t one-quarter of tho e for tIle conventional aileron on tbe rectangular wing.

It i appreciated tbat tbe area of the wing-tip ailerons could be con iderably increased in size with an accom­panying increase in eiIectivene s before the stick forces approach those of conycn tional ailerons. (ee refer­ence 5.) Tlti in crea e in ailcron area could not be accompli hed, llOweveJ' , wiLh out unduly inC'reasing Lbo span Hnd weigh t of Lhe wing. IL is believ d that LIl e \\-ulg-tip aiicrons LesLed are Lhe IUl'gesL size pl'ac tiea ble [or the wino'.

CO CLU IONS

1. The effectivene of tbe conventional ailerons was lightly greater on the tapered than on the reetangular

wing but the difference was not sufficient to be appre­ciated by the pilots.

2. The floating wing-tip ailerons were considered un­sati factory because their rollrng action was approxi­m lttely hltl£ that for the conven tionnl ailerons.

L ANGLEY MEMORIAL ERO AUTICAL L ABORATORY,

N A'fIO TAL ADVI ony OMMI'I''rEE FOH AEHO fA U 'I'T CS,

1, .\NC:I.T,; y 11' ''';1.1) , \ '/\ . , O('tohf' 1' ;37, f rJ87 .

I. \\·r·jek, Fred K, a lld '\\-rti zillj!N, arl .J. : Wind-Tullnel H.e­l>Ca rcll Comparillg I,at. ' ra t COlit rot DC\' it:('~ , Particularly ai, I righ Anglcs or Uack . 1 X . T apc red Wi ngs \I it.1t Orrli­lIan' Ailerons. T . . TO. 449, . A. C. A., J !'J33.

2. \\ '(, 11 7, i ngcr, Carl J.: " 'ind-Tunncl Ilwcs (,igatioll of Taper d Wings \I' ith Ordillary Ailcr ns and Partial-Span I lit Flap. T. R. J o. 611 , N . A. C. A., 1937.

<l . Wcick, Fred E., and J one , Robert T.: Resum e and Analy. is of N. A. C. A. Lat ral Control Rcscarch. T . R. No. 605, N. A. C. A., 1937.

4. 01l16, H. A., and McAvoy, W. n .: Flight I nve Ligation of Lateral Control Devices for se with Full-Span Flaps. T. R. No. 517, . A. C. A., 1935.

5. Weick, Fred E., and Harris, Thomas A.: Wind-Tunnel Rc­search Comparing Lateral Control Devices, Particularly at High Angles of Attack. XI. Various Floating T ip Ail­erons on Both Rectangular and Ta pered Wings. T. . No. 45 , N. A. C. A., 1933.

u . s, GOVERNMEN T PRINTING OFF ICE: 193 9

"­ "-'-

8

z Positive directions of axes and angles (forces and moments) arc shown by arrows

Axi" I I :r.lom('nt abo1lt axis I Angl(' I Velocities

---Force 1

Linear

Designation Sym-(parallel to axis) D('signaLion fhll1- PO ' iti\'(, Designa- YJll- (com po- Angular

bol

I Loo,it,d'n. L __ . _I X I Lateral ___ __ }-

NormaL __ Z

Absolute coefficient L

O'=qbS (rolling)

of moment O=M

m qcS (pitching)

s~'mbol

X Y Z

1-

Pitcl~ing ____ Rolling_ _ _ _I

Ya\nng ___

X O"=qbS (yawing)

hoi

-

L JIJ .\'

direction tion hoi llentalong axis)

- - -I I -' - -} . -'lZ RolL __ '1 </) u Jl Z --'I X Pitch ___ _ 0 v q X )- Yaw ___ . >l- ll' r

I -- ---

Angle of set of control sW"fuce (relative to neutral position), O. (Indicate surface by proper subscript.)

4. PROPELLER SYMBOLS

D, P, plD, V', V.,

T,

Q,

Diameter Geometric pitch Pitch ratio Inllow yelocity Slipstream yelocity

T Thrust, absolute coefficient OT= 2D4

pn

Torque, absolute coefficient CQ= ~D5 p1/.

P,

as,

11,

Power, absolute coefficient CP = ~nr. pnJ.F

Specd-powE'l' COC[fiCient=-V ~~~: Efficiellcy RCTolutions pCI' , ('cond, l·.p .

Eff~cti\'e helix angle= tan-Ie .... 17 ) ~7Trn

5. NUMERICAL RELATIONS

1 hp.=76.04 kg-m/s=550 ft-Ib./sec. 1 metric horsepower= 1.0132 hp. 1 m.p.b.=0.4470 m.p.s. 1 m.p.s.=2.2369 m.p.h.

1 lb. =0.4536 kg. 1 kg=2.2046 lb. 1 mi.=1,609.35 111.=5,2 0 ft. 1 m=3.2808 ft.