ACE No. L5F13a NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS WARTIME REPORT ORIGINALLY ISSUED July 19^5 as Advance Confidential Report L5F13a EFFECT OF LEAKAGE PAST AILERON NOSE ON AERODYNAMIC CHARACTERISTICS OF PLAIN AND INTERNALLY BALANCED AILERONS ON NACA 66(215) -2l6, a = 1.0 AIRFOIL By J. D. Bird Langley Memorial Aeronautical Laboratory Langley Field, Va. UNIVERSITY OF FLORIDA DOCUMENTS DEPARTMENT 120M ;N SCIENCE LIBRARY P.O. BOX 117011 GAINE 'II E FL 32611-7011 US£ NACA WASHINGTON NACA WARTIME REPORTS are reprints of papers originally 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 - 172 h?X tw-ty NACA ACR No. L5F13a NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS ADVANCE CONFIDENTIAL REPORT EFFECT OF LEAKAGE PAST AILERON NOSE ON AERODYNAMIC CHARACTERISTICS OF PLAIN AND INTERNALLY BALANCED AILERONS ON NACA 66(215 )-2l6 5 a = 1.0 AIRFOIL By J. D. Bird SUMMARY An investigation has been made in two-dimensional flow to determine the effect of leakage past the aileron nose on the aerodynamic characteristics of ailerons. Plain and internally balanced ailerons of 0.20 airfoil chord vrere tested on an NACA 66( 215 )-2l6, a = 1.0 air- foil. The effects of amount and type of leakage, aileron contour j, and Mach number and Reynolds number were investi- gated. The results of the tests indicated that a small amount of leakage area changed the pressure distributions over the plain and internally balanced ailerons markedly. This change generally resulted In negative increments in the lift and hinge-moment parameters cj fi , C]-, , and c^ A further Increase in the leakage area produced smaller changes in these parameters for the Internally balanced aileron. INTRODUCTION Numerous investigations have been made in an attempt to develop ailerons with satisfactory hinge-moment char- acteristics. One of the most: promising types yet devised and tested is the internally balanced aileron; however, installing and maintaining a complete seal across the entire aileron span, especially near the hinges, is rather difficult. It was therefore advisable to investigate the CONFIDENTIAL NACA ACR No. L5F13a effect of leakage past the balance plate on the character- istics of internally balanced ailerons. Several investi- gations have already been made with the nose gap unsealed and a correlation of some of the results is given in refer- ence 1. The present tests were made in an attempt to provide additional information on the characteristics of inter- nally balanced ailerons and to determine whether a suffi- cient degree of balance can be maintained if the nose seal is eliminated. Because of the poor correlation of prelimi- nary test results with existing data, it was found desira- ble to investigate the effects of Reynolds number end Mach number and the amount and type of leakage area on the characteristics of the internally balanced aileron. Tests were also made to determine the effect of an aileron- contour modification on the characteristics of the unsealed internally balanced aileron and the sealed and unsealed plain ailerons . SYMBOLS AND DEFINITIONS The coefficients and symbols used herein are defined as follows; c I airfoil section lift coefficient ( — ) Cft aileron section hinge-moment coefficient a / I airfoil section lift h aileron section hinge moment c airfoil chord c a chord of aileron behind hinge axis ct, chord of balance plate ahead of hinge axis /l ?\ q free-stream dynamic pressure ( — pV ! V 2 / V • free-stream velocity p mass density of air CONFIDENTIAL NACA ACR No. L^FlJa CONFIDENTIAL g q angle of attack of airfoil for infinite aspect ratio 5 aileron angle with respect to airfoil c^ = ( ' \ measured at a = 0° /ocA c h _ = [ i measured at 5 = 0° 5 " \d0/ a measured at a = 0° measured at 5=0° M Mach number (V/a) a velocity of sound P oressure coefficient -^ q p local static pressure on aileron or balance plate P free-stream static pressure The subscripts outside the parentheses of the para- meters indicate the factors held constant. The terms used herein are defined as follows? Nose gap distance between nose of aileron or balance plate and adjoining wing (figs. 1 to J) Vent gap distance between aileron nose and balance shroud or cover plate (figs. 1 and 2) End gap distance between end of balance plate and adjacent tunnel wall (fig. 3) CONFIDENTIAL k CONFIDENTIAL NACA ACR No. L5F13a Equivalent nose gap gap obtained by adding to nose gap the quotient of area at ends of balance plate divided by model span Hinge gap opening surrounding aileron hinge APPARATUS AID TESTS The tests were made in the two-dimensional test section of the Lang ley stability tunnel; this section is rectangular and is 6 feet high and 2— feet wide. Since the model, which is an NACA 66(21S)-21b, a = 1.0 airfoil section of 2-foot chord, completely spanned the width of the test section, two-dimensional flow was approximated. Table I gives the airfoil ordinates. The 0.20c plain and Internally balanced ailerons tested are shown in figures 1 to 3 • A continuous flexible seal of cloth impregnated with plastic was used for the tests in which the nose gap was sealed. In all of the tests except that in which the aileron was completely sealed, there were gaps of approximately 0.001c between the ends of the balance plate and the tunnel walls. (See fig. 3«) For the completely sealed aileron, these end gaps as well as the nose gap were sealed. The vent gaps were unsealed for all tests. A concentrated leakage area simulating a hinge gap was obtained by sealing the nose gap completely and cutting a rectangular hole in the balance plate . The airfoil and the aileron were mounted between two end disks that were rotated to change the angle of attack of the airfoil. Aileron hinge moments were meas- ured with a spring balance . Lift was measured by an integrating manometer connected to orifices In the floor and celling of the tunnel. Pressures were measured through flush orifices installed 1 at the center of the span of the aileron and balance plate. Table II gives the chordwise locations of these orifices. All of the tests except the tests to determine the effect of varying the Reynolds number and Mach number were made at a test Mach number of O.36, which corresponds CONFIDENTIAL NACA ACR No. L5F13a. CONFIDENTIAL to a Reynolds number based on standard atmospheric con- ditions of approximately S.l x 10 ^ . The relation between Reynolds number for standard atmospheric conditions and test Mach number is shown in figure L\.. PRECISION OF TESTS Angles .of attack were set within ±0.1° and aileron angles within ±0.3°. Check tests indicated that, at a Mach number of o/jb, values of cv, were accurate to within ±0.005; ct, , within ±.0.01; and P, within ±0.03 Corrections for jet-boundary effects were applied to the lift coefficients and angles of attack. The cor- rected values were computed as follows; cj - O.963 cj T a =. 1.023 a OT where cjrn and a 0T are the uncorrected lift coeffi- cient and angle of attack. No corrections were applied to the hinge-moment coefficients. RESULTS AND DISCUSSION Presentation of Data Porce-test data for the present report are given as section, lift and aileron section hinge-moment coefficients plotted against aileron angle for a range of angle o± attack or Mach number. The data for the sealed and unsealed true-contour plain ailerons are given in fig- ure 5- Data for the internally balanced aileron with a constant vent gap of 0.010c and with end and nose gaps sealed are given in figure 6; with end gaps of 0.001c and nose gap sealed, in figure 1\ and with end gaps of 0.001c and various nose gaps, in figure 8. Pressure distributions over the aileron and balance plate are given in figures 9 to H- Results of tests of the inter- nally balanced aileron with concentrated leakage area CONFIDENTIAL CONFIDENTIAL NACA aCR No. L5F13a for determining the effect of limiting the spanwise dis- tribution of leakage past the balance plate are given in figure 12. Results of tests with reduced nose and vent gaps for determining whether the leakage area or the ratio of leakage area to vent area caused the greater part of the effects of leakage are given in figure 13 . Data for the sealed and unsealed plain ailerons with straight sides are given in figure llj.; for the unsealed internally bal- anced aileron with straight sides, in figure 15. The effect of Mach number and Reynolds number on the hinge - moment characteristics of the internally balanced aileron with leakage past the balance plate is given in figures l6 and 17. Effect of Increased Leakage Snail aileron angles .- The values of c Z,a> c h ' and CI15 for the plain and internally balanced ailerons are made more negative by increased leakage past the aileron nose or balance plate; the greater part of the change for the Internally balanced aileron occurs for a small equivalent nose gap (fig. 18 ) . The equivalent nose gap is obtained by adding to the nose gap the gap obtained by dividing the area at the ends of the balance plate by the span of the model. The value of cj a is little affected by increased leakage. An equivalent nose gap of 0.0002c, with the end gaps unsealed, caused the values of chc to become appreciably more negative. A compari- son of the pressure distributions on the unsealed inter- nally balanced aileron with the pressure distributions on the sealed internally balanced aileron (reference 2 and figs. 9 to 11) indicates that leakage past the balance plate produces a marked change in the pressure distri- bution on the aileron. This change in the pressure dis- tribution, in addition to making the part of the aileron behind the hinge axis heavier and thus moving the center of pressure of the aileron nearer the aileron trailing edge, decreases the induced balancing pressure of the aileron. The curves of c nf - for various angles of attack indicate that small amounts of leakage past the balance plate are less critical at large angles of attack than at small angles of attack (fig. lo). For large amounts of leakage past the balance- plate , the decrease in balancing pressure and the increase in heaviness of the part of the aileron behind the hinge axis become so CONFIDENTIAL NACA ACR No. L?F13a CONFIDENTIAL 7 great that the unsealed internally balanced aileron becomes heavier - that is. has a more negative value of chg - than the olain sealed aileron. The pressure distributions behind the hinge axis of the unsealed internally balanced aileron and the unsealed plain aileron show a marked similarity. This similarity is to be expected since the pressure distribution over the aileron surface is a function of the amount of leakage through the aileron as well as of angle of attack and aileron angle. For the unsealed plain and internally balanced ailerons compared In figures 9 an< ^ 10, tne amount of leakage should be of the same order of magnitude because the nose gaps are equal. Part of the leakage effect shown in the tests reported herein results from the existence of an extremely adverse pressure gradient near the trailing edge of the airfoil tested which, for a given amount of leakage, tends to cause separation farther forward on the airfoil than would be the case if a less adverse pressure gradient existed. Unpublished data on airfoils with a less adverse pressure gradient near the trailing edge have proved such airfoils to be less sensitive to leakage than the airfoil tested. The Internally balanced aileron tested is much more sensitive to leakage past the balance plate than the ailerons for which the correlation of reference 1 was made (fig. 19)= The values of the balance ratio are more negative for the aileron tested than for the ailerons of the correlation curve for the range of leakage area shown in figure 19 . It should be noted that most of the increase in heaviness (more negative value of chg ) of the aileron tested occurs for small amounts of leakage area, whereas the increase in heaviness indicated by the correlation curve (reference 1) varies gradually with increase in leakage area. The sensitivity of the inter- nally balanced aileron tested to small amounts of leakage area would make close aileron balance difficult without use of a complete nose- seal. Large aileron angles .- The slope of the curves of aileron hinge-moment coefficient against aileron angle for the unsealed internally balanced aileron (fig. 8) becomes less negative at large aileron angles and thereby indicates an increase in the degree of hinge-moment CONFIDENTIAL 8 CONFIDENTIAL NACA ACR No. L5F13a balance. This trend Is opposite that obtained for the usual aerodynamic balance. It should be noted that the aileron angle at which this Increase occurs is a function of the angle of attack. The change in the slope of the curves of hinge- moment coefficient at large aileron angles is caused by an abruot increase in the rate of increase of balancing pressure (and thus of hinge -moment coefficient of the balance plate) with aileron angle as well as a positive increase in the value of c^c of the plain unsealed aileron (fig. 20). The pressure distributions (figs. 9 to 11) indicate that the negative pressure causes the abrupt change in the slope- of the curve of hinge-moment coefficient of the balance plate plotted against aileron angle . Effect of Type of Leakage A comparison of the hinge-moment characteristics of the aileron with concentrated leakage area at the mid- span, of the aileron with the reduced nose and vent gaps, and of the aileron with the 0.005c nose gap and 0.010c vent gap is given in figure 21. All of these ailerons had approximately the same ratio of leakage area to vent area. Figure 21 shows that the aileron with the reduced nose and vent gaps has more closely balanced hinge-moment coefficients than the other two ailerons at large positive and negative aileron angles and has as close a degree of balance as either of the other two ailerons at small aileron angles. The aileron with the concentrated leakage area has less balance than either of the other two ailerons at both positive and negative aileron angles, except at very large aileron angles for which its degree of balance increases rapidly. This trend is similar to that of a control surface with plain overhang and hinge gaps as tested for reference 3- The hinge-moment charac- teristics of the internally balanced aileron with leakage past the balance plate generally were not changed radi- cally by changing the leakage area from a narrow slit spanning the aileron at the balance-plate nose to a rectangular hole of about the same area located at the model midspan. The values of balance ratio for the ailerons with the concentrated leakage area and with the reduced nose and vent gaps are plotted in figure 19 against the ratio of leakage area to vent area. CONFIDENTIAL NACA ACR No . L5F13a CONFIDENTIAL Effect of Aileron-Contour Modification The curves of c^ and cj plotted against 5 for the straight-sided plain and internally balanced ailerons (figs. ll|_ and 15) show the results to "be expected from increasing the trai ling-edge angle of the airfoil. The value of balance ratio from the tests of the straight-sided aileron is plotted against the ratio of leakage area to vent area in figure 19 . This value of the balance ratio was obtained by use of the values of chg for the straight-sided plain and internally balanced ailerons as determined from tests and the esti- mated value of cjig for the sealed straight-sided inter- nally balanced aileron. The value of ch 5 for the sealed straight-sided internally balanced aileron was estimated by correcting the data for the sealed true- contour internally balanced aileron for the effect of the change in trai ling-edge angle. Effect of Mach Number and Reynolds Number A comparison of figure 22 with data from reference It indicates that Mach number and Reynolds number have only slightly more effect on the values of ch fi for the unsealed internally balanced aileron than for the sealed internally balanced aileron. The variation of chg with Mach number and. Reynolds number is in opposite directions for the angles of attack of 0° and 10.2°. These results indicate that, for the range of Mach number and Reynolds number tested (fig. it), the effect of Mach number and Reynolds number on the values of chg was not appreciably different for sealed and unsealed internally balanced ailerons . CONCLUSIONS' The effect of leakage past the aileron nose on the aerodynamic characteristics of plain and internally bal- anced ailerons on an NACA 66(215 )-2l6, a = 1.0 airfoil has been investigated in two-dimensional flow. From the results of this investigation, the following conclusions have been reached: CONFIDENTIAL 10 CONFIDENTIAL KACA ACR No. L5F13a 1. A small amount of leakage area changed the pres- sure distributions over the plain and internally balanced ailerons markedly. This change generally resulted in negative increments in the lift and hinge-moment para- meters cj-, c h a > an( l c h« • A further increase in the leakage area produced smaller changes in these parameters for the internally balanced aileron. 2. The sensitivity of the internally balanced aileron tested to small amounts of leakage area would make close aileron balance difficult without use of a complete nose seal. 3- The hinge-moment characteristics of the internally balanced aileron with leakage past the balance plate generally were not changed radically by changing the leakage area from a narrow slit spanning the aileron at the balance-plate nose to a rectangular hole of about the same area located at the model midspan. Lj_. Reducing the amount of leakage area and vent area so as to hold constant the ratio of leakage area to vent area increased the degree of hinge-moment balance at large aileron angles but caused no appreciable change in the degree of balance at small aileron angles. 5. The sealed and unsealed internally balanced ailerons had almost the same variation of c\^ with Mach number and Reynolds number. Langley Memorial Aeronautical Laboratory National Advisory Committee for Aeronautics Langley Field, Va . CONFIDENTIAL NACA ACR No. L5F13a CONFIDENTIAL 11 REFERENCES 1. Rogallo, F. M., and Lowry , Jtfhn G.: Resume of Data for Internally Balanced ailerons. NhCA RB, March I9k3, 2. Letko, W., and Denaci, K. G. ; Wind-Tunnel Tests of Ailerons at Various Speeds. V - Pressure Distri- butions over the NACA 66,2-2l6 and NuCA 23012 Air- foils with Various Balances on 0.20-Chord Ailerons NACA ACR No. 3K05, 19^3 • 3- Nivison, J.: Effect of Hinge Gaps on Control Charac- teristics. TN No. Aero 9 8 3 (Large Tunnel), British R.A.E., July 1914-2. L. Denaci, H. G., and Bird, J. D, : Wind-Tunnel Tests of Ailerons at Various Speeds. II - Ailerons of 0.20 Airfoil Chord and True Contour with 0.60 Aileron-Chord Sealed Internal Balance on the NACA 66,2-216 Airfoil. NACA ACR No. 5Fl8 , I9I4.3 . CONFIDENTIAL 12 CONFIDENTIAL NACA ACR No. L5?13a TABLE I ORDINATES FOR NACA 66(215)-2l6, a = 1.0 AIRFOIL [Basic airfoil contour. Stations and ordinates in percent airfoil chord] [Toper surface Lower surface Station 1 Ordinate j Station Ordinate .L.01 .61+0 1.128 2.562 4-846 1.3ko 9.833 14.8L5 19.860 24.879 29.9OO 34.921+ ll-U 50.000 55.025 60.048 65.067 70.081 75.087 80.085 85.075 90.055 95-028 100.000 1.230 1.484 .1.858 2.560 3.6014- 4-128 5 . iko 6.276 7.156 7.844 8.*66 3.736 8 .. 980 9.092 9.060 8.875 8.I4.96 7. 362 6.941 5.860 4-644 3-395 2.103 .913 -599 .860 1.372 2.638 5.154 7 .660 10.162 15.155 20 . 140 25.121 30.100 35-076 40,051 [1,5.026 50.000 54-975 59-952 64-933 69.919 74.913 79.915 84.925 89-94-5 94.972 100.000 -I.I30 -1.344 -1.644 -2.188 -2.972 -5.580 -4.106 -4-930 -6 .054 -6.422 -6.576 -6.838 -6.902 -6.354 -6.68S -6.554 -5.802 -4-997. -4-070 -3-052 -2.o49 -1.069 -.231 L.E. radius: 1.575- Slope of radius through L.E. : 0.084 NATIONAL COMMITTEE FOR ADVISORY AERONAUTICS CONFIDENTIAL NACA ACR No. L5F13a CONFIDENTIAL 13 TABLE II CHORDWISE LOCATIONS OF ORIFICES FOR UNSEALED INTERNALLY BALANCED AILERON OF TRUE AIRFOIL CONTOUR Locations in percent aileron chord] Location forward of Location behind hinge hinge axis axis 72.3 I;..2 66.8 11.5 - 56.7 32.3 1+5-7 68.8 23.0 89.6 12.5 k.z NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS CONFIDENTIAL NACA ACR No. L5F13a Pis?, la-c CONFIDENTIAL 7o /e&c///7<7 ecfye M P/0//7 oz/eror? , sea/etZ or c/nseo/eeZ - Cover p/a/e _.0/0c vent Vor/af/oo of 6o/<7r?ce chord mZ/p nose ?&/> AZose #&/) %/'<, 0-OOOSe 0-7(56 OOZ5c ■76/ ■0030c ■754 ■0050c ■744 ■ 0/00 c ■7/9 7o /eoi//r7f etZ^e (6) I/yZerrtaZZy Z>aZor?r'e>e/ o/Zeror? , sea/ea' . — l/er?/ pop NATIONAL ADVISORY COMMITTEE FM AEHOKWJTICS /4.6' 7b ZeooZ/r?^ eotye fc) ff?fe/~r70//y Z>oZar?cecZ a/Zeror? , t/r?seaZea' ■ Z r /^i/re / --rrc/e-con/oo-r o/Zeror?s fesZe/Z or? 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(9 -OS t/<5 ?. 8c CONFIDENTIAL ! + O G A X v □ oU> \ \ ^c M \ '>Lt^ ^ Y g l£ O) ^ ^ § o (deal ci) ■0 ID '0.2^ X ^ ^T / ■y. / 3 xr -w A 7 > Y 1 7 l r X / ft - i *± >- -U sf >Y 7./ H f^ A k — i T i / x- ' > r 4 O S3 2 ft n CD Y* ^ £f r< ^ r"" ^ 7^ ^ V / V > t ° Q -k «/ Y •r 2 7 £L y - A s y / ^ M. y / W ^ V r . / X ^_ 26 / V y ' ^. y> *■ -<^ Y* r~ j^ ~x & a^ i-O.OOJOc gap ; Y _ 57 V 77^===^ r 0.0/0 c venf gap -k ° 6 ./ x^ / r =/^ — Cj) ° <0 ^ ¥_ s S \ = V_-i -^~~~\ ^8 < > > ^t\==*=******** 1 ° ^-True con, 'to [If <0 k 1 J % ^ \J * ■5) V Ml — c> ^S 03 I Hi ^. ■** »o -0 Pi ^ C ~5 C3 1 -+~ ?• c < f^ «1 £ ^ t» C3 £ ^ 1 5 Vi *0 4S "^ <: c u it) 13 -S 5 3 .555 «; NACA ACR No. L5F13a Fig. 12a c roN FIDEN riA L -/•7a"x-8.z" ho/e \ ~7 Ca "** == *=== ?< / __— -— tftf/0 \ s v fvl 4sE \y h /■O t 'eg) \2 (a /c "0 -■16 •a XX- JF ^ yi \ K^ y <* A A ■6 -- ^ ~xr ,> rf ^ r p" > sr ,> & 5 / vT .4 r S-l r*-' _ r ^. & ■** i v> -Z § o S <, , -1 XC s ^ r c X y -t-"' ( °xf S>r > y/ &!> ^/ ^, ' ^ t^ F -rt5 / r r V^ ^a y r s. NATIONAL ADVISORY COMMITTEE FOB AERONAUTICS -/c? /+- 1 c ON FID EN1 IAI 1 1 1 I 1 ( ?J £"<2V ice/ n/n y/ec i h 'art ?ge ar eo ' j /./ '8 i by aL7fr^-— .08 H \ y%T}^r/ \ \ \> \ l^J^^f****** True confour U" ^-3e<7/ — 1 .04 ^ V R V l i \ x \ I 1 1 I 1 1 \ V / / / / o 1 \ V, \ \ \ \ < n \ N / / 1.4 \ X > / \ \ \ 4 / ^p * 11 -.08 Q 5 IZ \ L \ > >( k -T" * ^ L V) \ s r 1.0 5: w ^x «7 /o.z ^1 P r^ °v •a. ^O^A^; ^*Tr .8 E 1 ~0~ tf- c / ,*' u T^ ^ r /■ . ^ ^ s Y ^ XT' M V ^ s* 8 is ^ / "' ^1 f" ^ ^ -5. -.6 ?K =K -.5 . +^ NATIONAL DVISORY COMMITTEE FOk AERONAUTICS > / HO /+' CONFIDENTIAL * 1 I 1 1 1 ^ °<5>/7< r ' /.£ 7 / nch es. -ZO -16 -IZ ±-8-4 O 4- 8 /2 /6 ZO /^iQure /Z ■ - Conc/uo/ed ■ NACA ACR No. L5F13a Fig. 13 0.002SC gap 0.005c vent gap < •k I to -zo -/s -tz /a /6 zo -8-4 O 4 8 A'ts.ror7 ang/e, S , deg F/gure tJ ■ - Variation of sect/on lift and hinge -moment coefficients with o/leron ang/e ■ True-contour 0.7 JCa /nternat/y batanced aileron ; vent gap j , 0.003c $ end gaps , 0.001c ; nose gap , 0.00,25 c ,- AA--0.J6 ■ NACA ACR No. L5F13a Fig. 14a "V, S 1 I 1 °0 CONFIDENTIAL r~~~--~--___^ r0.005c gap — (--- -W/-\ if ~~~~--~_ 5/tfes ~ ( ■X n «d£>(7 . O-i /O.Z-, / 1.6 1.4 y-E t.Z 1.0 LL (deg) .8 /&■£ o .6 1 f 4 D— " Z S r* ■;, \ ■ r2 NATIONAL ADVISORY COMMITTEE FOR AE*ON ^1 > S x -.04 1 $ -06 S -12 &» & > ^ -16 ^ v. ^ -20 to AA-0-J6. NACA ACR No. L5F13a Fig. 14b 1-6 1+ IZ I.O & .6 4- ■Z -rZ -4 -J5 o CONFIDENTIAL \ x \ ' ~~~->**^~ O.OOSc gap \ i r*^^ b \ - S^~r~^ N \ \ 5/des \ X \ N ^ i V, J ~~ ^ c^.deq, JO-2 a cu \ ,A K D s V, < p > x\ t L i"5* ex -o r V \ \ ^c fcfe 0> t V \ V 3— C JO. ^t K 5 f 1 \ feu \ /■ y < u Y ^N K 8 s ^ \ >> \ fc * t > § \l 1 ^r *> <0 o Ft 7* A Y k NATIO COMMUTE NAL ADVISORY £ FOB AERONAUTICS '(a *; (/m -eoA ?c . C :on FIE EN riAL zo .16 JZ C? .08 jo .04- fT i xt ] \ 8 Y' jj ^ ^ ^ ^ET -r~^- > j %* (Y k) >^ V V ^ r xsr jj ^ r u r o rr XSr ,~-^ r -z NATIONAL ADVISORY COMMITTEE FOB AERONAUTICS -4 CONFIDENTIAL -20 -16 -12 -8 -4 O 4 6 12 16 20 /I/Zero/? o/7#/e , 6 , deg Figure /5 .-Variation of section lift and hinge -moment coefficients with a iter on angle .Sfraight-s/ded 0.7dc a internally balanced aileron ■, vent gaps } 0.010 c $ end gaps , 0.00/c } nose gap , 0.005c - ? M = 0.36 . NACA ACR No. L5F13a Fig. 16 S I 3 -ZO -16 -IZ. -3 -4- O IZ. /6 ZO Figure /6.- Effect of Mach number or? the variation of h/nge -moment coefficient w/th a/teron angle, frue -contour 0.73 c a inter natty balanced a/tenon : vent gaps, 0.010c ■, end gaps seated } nose gap , 0.O05c 7 - a = V" . (/Vote staggered scales .) NACA ACR No. L5F13a Fig. 17a -20 -16 -12. -Q -4 O .12. .03 .04. tZ, , .03 < CONFIDEJ vlTW XL -0.0025 c gap \ ~~rf :s=s ===== s ^ ___— — 0.005 c v&nt gap / \ — C^T~~~~~^~~~~~~^ '-Tree con four k -t ,/iC .08 A s a. "~x~ — x X- \ .04 JZ, N v ^ <^ s \ \ \ o m 5 k X X v| K 5 s \ \ k -.04.04 .12 \ •** N X N \ > V 1) ■^ k A \ ^5 \ \ -as o .as | U + — - -.08 €3 + A \ > \ 0-4/8 ^ V ^ k \ V fy 5 Ly\ N \ K *-s ~-> ■358 ^ 5 -IZ-.04 ■ V N ^r \ \ -x^ v q 1) J*h t"- s+ % "^ i -Z90 ^ < -JZ-04 < -JO -.03 r> t/6 + \- - + N NATIONAL ADVISORY COMMITTEE FOB AERONAUTICS It 7) &o = o CONFIDEN TIAL /Z /6 Z.O Ai/eron anp/e , 3 } deg Figure /7 ■ -Fffect of AAach number on The variation of hinge -moment coefficient with ai/eron ong/e . True- contour 0-75 Cq internally ba/anced aiteron ■. vent gaps , 0.005c - } end gaps , 0.002 c j nose gap , 0.0025c ■ (Note staggered sca/es.) NACA ACR No. L5F13a Fig. 17b 0.0025c gap 0.005c vent gap v -ZO -/6. -IZ. -3 -4- O 4 & Ai/eron ong/e } c5 _, deg F/gure / 7 • - Conc/uded ■ IZ 16 ZO NACA ACR No. L5F13a Fig. 18 o / CONFIDENTIAL ZeoAiJ^e area , sq Z 3 A 3 6 7 - L i i L&aMage area obrav ,P/a/n seofed a/fer J] P/a/r? anseoted — v oeo oy unjeaV/ng c?o/o^ of- on ends of a//<°r~on ./z l " .08 / aileron 1 \c 7 at S -0° h s \ _Jl ^7- V ^v~ ft- t C ?5 -° 4 4 -J c ? j or cc =o ■A. -A— \ A * -A > v . > ^ < -004 c ' \ 5=0° 5^ £ 1 -.008 r -P/a/r? seated i — O a/tenor? T P//7//7 c//?seated a/ternr? I 6=0° _ 6=0° ■008 r ■004 L t NATIONAL ADVISOBY COMMITTEE F0« AERONAUTICS % ° S \ n; ^s t n a -.004 ^ R \ (deg. t \ fe N s4_ ^\ i_ - r~5J ^008 -x— / *--~ ■Q ■s ^-P/a/r? sea/ed o//ero/7 , 0Cff0° -ti/Z i -P/a/r? ar?sea/ed c ) -/ r •x > •J > ■A r ■5 -6 -7 -6 ? .6 > / Equivalent nose gap , percent c Figure IS. - Variation of lift and hinge -moment parameters with leakaqe area ; true-contour plain aileron and true- contour 0.7Jc o internally balanced aileron with 0.0 W c vent gaps } AA=0.J6 . CONFIDENTIAL NACA ACR No. LOFiSa Fig. 19 CONFIDENTIAL NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS Leo '/cage area / \Zer?f area Figure /9 . - Vernation of batance ratio with ratio teak age area to vent o/rea> - } ha /a rice ratio of computed by using c> of pJam sealed ai/eron ■ M -- 0.J6 ; oc„=0 NACA ACR No. L5F13a Fig. 20 1 si k u > 1- a s ° 3 « o > a i< Z ui o £ *3 ^ - Si | <0 i- I- I- K If 1 I '1 1 % ^ °0 SN II r I i I ?0 ' ^iSJ/J/JJdOJ J£JJ66/06t/-dfic//C/ U0/JOO£ a ^ So NACA ACR No. L5F13a Ki?. 21 V J ' /6JJ/J/JJJOJ J6/ ^ $ * § $ v5 *' $ ^ ^ 5 ^ $ *