1、, ACR No. 4A13e iNATIONAL ADVISORY COMMITTEE FOR AERONAUTICSWARTIME REP()RTORIGINALLY ISSUEDJanuary 191_4asAdverse Confidential ReportCOLLECTION OF _ED-AILERON TEST DATABy F. M. Po_alloLsr4_ey Memoriel Aeronautical LaboratoryLangley Field, Va.J P I,I_ALir(_IAINSliTUIECAS FIL COpyl,i 1lea RYOF1E_HNOL
2、OGYNACAWASHINGTONNACA WA/ATIME REPORTS are reprints of papers originally issued to provide rapid distribution ofadvance 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 n
3、ot tech-nlcally edited. All have been reproduced without change in order to expedite general distribution./_.R 19 1946L- 419Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-llp11,Provided by IHSNot for ResaleNo reproduction or networking permitted wit
4、hout license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSADVANCE CONFIDENTIAL REPORTCOLLECTION OF BALANCED-AILERON TEST DATABy F. M. RogalloSUMMARYTest data of balanced ailerons Lave been collected from NACAand British sources. These data, which are presented in the formof charts, are gr
5、ouped as A - ailerons with Frise balances, B -ailerons with blunt-nose balances, C ailerons with internalbalances, D - ailerons with contour modificatlons, and E -ailerons with tabs. Results of flight tests and of wind-tunneltests in both two- an4 three-dimensional flow are presented butno correlati
6、on nor r6sum of the data has been included. R6sum_sare being published separately as completed.INTRODUCTIONThe demand for high rates of roll at high speed in combataircraft and the general increase in the size and speed of air-planes of all types have made it necessary to provide very closeaileron b
7、alance.Provision of close balance at large aileron deflections athigh speed frequently results In overbalance at small ailerondeflections or at low speeds. In some installations, moreover,an undesirable shaking of the controls has occurred under someconditions of flight.Many experimental investigati
8、ons of ailerons have been madebut all the results obtained have not been available to themanufacturers and, in general, the results have not been corre-lated nor summarized. A large amount of test data has beencollected herein for convenient reference. These data are beinganalyzed, correlated, and s
9、ummarized by the NACA; the results ofthese studies are being published separately as completed.(See references i and 2.)IwProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Test results of balanced control surfaces of larger chord thanare generally used
10、 for ailerons are not included in the presentcollection but are collected in reference 3.CLASSIFICATION OF DATAThe present collection of data Is divided into five sectionsas follows:are :OLCDc_cdoChchC_A - ailerons with Frise balancesB - ailerons wlth blunt-nose balancesC - ailerons withlnternal bal
11、ancesD - ailerons wlthcontourmodlficationsE - ailerons with tabsThe parameters and symbols used In the presentation of datalift coefficientdrag coefficientsection lift coefficientsection profile-drag coefficienthinge-moment coefficientsection hinge-mount coefficientrolling-moment coefficient about a
12、xis in plane of symmetry ofcomplete model or airplane, referred to wlnd axes,! Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CntCmcmpb/2VPPo(I,%8A),bYiYOyawing-moment coefficient about axis in plane of symmetryof complete airplane or model, referre
13、d to wind axespitching-moment coefflcle_section pitchlng-moment coefficient about quarter,chordpoint of airfoilhelix angle of airplane in rollrolling velocity; also, static pressurefree-stream static pressureangle of attacksection angle of attackangle of yawdeflection angleaspect ratioratio of tip c
14、hord to root chordwlng span; also used with subscripts to denote componentsof wingdistance from plane of symmetry to inboard end ofailerondistance from plane of symmetry to outboard end ofaileronwing chord; also used wlth subscripts to denote componentsof wingmean wing chord; also used with. subscri
15、pts to denote com-ponents of wingProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-t aAtRbqqoApPVViRMFsaileron semithickness at hingeincrease of aileron trailing-edge thicknessradius of Juncture between bevel and control surfacetrailing-edge angle, Ino
16、luded between sides which form trailingedgelocal dynamic pressurefree-stream dynamic pressurepressure across balancefree-stream velocityindicated velocityReynolds numberMach numberstick forceSubscripts:a aileronb balance; also, bevelf flaps stickt tabResults of flight tests and of wind-tm_nel tests
17、in both two-and three-dimensional flow are presented. Some of the data have beenreplotted and are given in a form different from that in the originalsource. Supplementary information on tho models and on the test con-ditions is glven in table I. This table also gives published refer-ences and serves
18、 as an index to the results presented because the modelor airplane designation is given in the first column of the table andProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-in the upper right-hand corner of each page of model drawings ortest results.
19、Some of the data have been corrected for tunnel-boundary effects When such corrections have been estimated butnot applied to the data, the estimated correction factors aregiven in table I.AILERONS WITH FRISE BALANCESThe results of tests and the test conditions for models andairplanes having ailerons
20、 withFrisebalances are given in tableIAand in figures A1 to A86. The section characteristics ofthree models equipped with Frlse ailerons are presented in fig-ures A1 to A13. In general, the ailerons tested did not seemvery satisfactory in the negative deflection range; that is, sharpbreaks occurred
21、in the hinge-moment a_i effectiveness curves atrelatively low negative deflections. This characteristic seemsto be caused by separation of flow at the protruding nose. Fig-ure A4 shows that such separation may be delayed considerably byincreasing the radius of the nose. A similar improvement wasobta
22、ined for the aileron of model A-VIII by raising the nosebut maintaining the same nose radius (fig. A59). The aileronsof model A.-III buffeted very badly over a large part of the neg-ative deflection range (reference 6) and only a few test pointscould be obtained in this region (fig. A13). The result
23、s of testsof various partial-span wing models and complete airplane modelsare presented in figures A14 to A49. Flight test results aregiven in figures A50 to A86. The improvement obtained by increasingthe nose radius is again evident from figure A22. Figure A_4 showsthat a high pressure peak can be
24、expected at the nose portionwhich protrudes below the lower surface even though the nose radiusis relatively large. The buffeting tendency of Frise ailerons wasagain evident in the tests of model A-VI (reference 7). Thedeflections at which oscillation occurred are indicated in figuresA27 to A34. The
25、 characteristics of the ailerons of this seriesof tests were improved by bulging the lower surface or by attachinga slat to the aileron nose. The same modifications were found toreduce aileron buffeting in the flight tests of airplane A-XII.In connection with this series of tests, it was pointed out
26、 thatbulging the lower surface may be unsatisfactory in some installationsbecause it increases the downfloating tendency of the aileron. TheProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-buffeting tendency of the ailerons of airpl_ne A-XVwas almost
27、ellm-inated by slightlyroducing the maximum neg_ive deflections. Prac-tically no_loss in effectiveness accompanied this alteration.AILR_ONS WITH BLUNT-NOSE BA_NCESData pertaining to the tests of models l_avlng ailerons withblunt-nose ba_nces are glveu in table IB aLd in figures B1 to B43.Section cha
28、racteristics for two models equlig?ed vith blunt-noseailerons are presented in figures Bl toB14. l_.eblunt-nose aileronson an NACA 2_012 airfoil seemed to be more _tlsfactory than similaraileronsp_on an NACA 66(215)-216,_ a = 1.O aTzfoil; that is_ the valuesdeflection range was greater for the NACA
29、2g012 airfoil. Increasingthenoser dilr su ted slightloss and slight_ knegative increase in 18Oh/85o) for small deflections but, becausethe ailerons with small nose radii tended to stall at lower deflections_the maximum values of Ac_ were usually greater and the correspondinghinge moments were usuall
30、y lower for the ailerons with larger noseradii. _ese characteristics n_y also be noted from the results oftests of blunt-nose ailerons on conventional and low-drag wing modelsof finite span as given in figures B15 to B52o The peak pressuresthat occurred over the noses of ailerons of this type were r
31、elativelyhigh, as may be seen from figure B17 That the effectiveness of _ileronswith blunt-nose balancesWas greater than the effectiveness of plainunbalanced ailerons is indicated by figure Big. The results of testsof a blunt-nose aileron on a complete airpla_Ja model are given in flg=ures B3S to B4
32、3. The effects of controllin_ the boundary-layer thlok-ness by fixing the point of transition _nd the effects of moving thehinge axis rearward to obtain a higher degree of balance may be obtainedfrom these results.Provided by IHSNot for ResaleNo reproduction or networking permitted without license f
33、rom IHS-,-,-7AILERONS WITH INYER_il_L BALANCESData pertaining to ailerons with internal balances aregiven in table IC and in figures C1 to C89. Section character-istics are sho_i in figures C1 to C35; data for flnite-spanmodels in figures C34 to C77; and flight data in figures C78 toC89. _.ny of the
34、se data have been aI_alyzed and summarized inreference 2 in which a discussion is f_iven of the balance required.The effects of changing the vent loc_tion, the surface contour atthe vents, or the amount of leakage _zcross the seal arc also dis-cussed and it is showu that these modifications may some
35、times beutilized for adjustment of the hinge_ioment characteristics. Theimportance of leakage cannot be over(_phasizod. The reduction ofaileron rolling-moment effectiveness due to leakage may be incon-sequenticl but a leakage area of onl_ two-tenths of the vent areamay reduce the effectiveness of th
36、e ii_ternal balance by 50 percent,as siiown in figure 7 of reference 2. The effects of varying the1ungoh of the fabric seal and of var_ing the shape of the balancechamber near the seal may sometimes te important but these effectscannot be deteimined from the data near available. An Investigationof t
37、hese variables, however, is now under way.AILERONS WITH COld.OUR MOD_ICATIONSThe material presented in table ID and in figures DI to D60includes data on several contour modifications that reduce hingemoments - such as bevels, bulges, and increased profile thickness -ai_ also data on several contour
38、modifications that increasehinge moments - such as trailing-edge strips, increased aileronchord and span, and d_creased profile thickness. Section charac-teristics are shown in figures D. to D17; data for finite-spanmodels in figures D18 to D54; and flight data in figures D55 _toD60. A preliminary c
39、orrelation has been made of the effect ofbevels at small deflections of sealed control surfaces (reference 1).The correlation was made on the basis of the included angle betweenthe upper and the lower surfaces at the trailing edge and includedmost of the data for sealed ailerons _resented in figures
40、 D2 to D39.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The improvement _n effectiveness and the m,_e nearly linear hinge-momentcurves obtainable by sealing the aiZuron gap when a bevel isused are shownin figures D22 to D24, D54, _nd D59._e data o
41、n bulged or bhlckened aileron profiles shownIn fig-ures I)46 teD48 were obtained on an unsealed Frise aileron. Theeffect Of the changedprof!lo was correlated in references 25 to 27with the maximumamount of the change In profile thickness and itsposition along the aileron chord as parameters. The off
42、 oct of ahollow or a thlckened profile on a plain sealed aileron Is showninfigures D2 to DV. An unsymmetrical bulge or bevel (figs. D30, D55,and )47) or a reflexed trailing edge (fig. D17) may be used to givean upfloating or a downfloatlng tendency; this effect maybe doslr-able if the aileron has a
43、d_fferentlal linhage.The aileron-contour modifications pre-_!ously mantlonod providebalance by utilizing the diffo=enco in the boundary-layer thicknessover the upper and the lower surfaces of tlJe rear portion of theairfoil in such a way that the lift over this portion is altered.The aileron effecti
44、veness _s indicated by the static rolling momentswill thus be reduced when a bevel or bulge ls used. As is pointedout in reference l, the loss in rolling po,;er of an aileron willbe less than the loss in static rolling mo_(_ntindicates, however,because the damping in roll is also reduced by the beve
45、l or bulge._be results of flight tests of several unsealed-aileron arrange-ments on a fighter airplane are given in flexures D56 to D60. Theeffects of using large traillng-edge angles and of fixing trans-ition are shown.The modifications shown in figures D16 and D49 to D54 areintended to increase th
46、e _atio o:C the hinge-moment parameters(_Ch/_ 5_ and (_Ch/_5_l Analysis show_ that increasing theh_ V5apositive value of the ratio ,-r-_,-_wil tend to lighten stickforcesduring rolling. (0Ch/_Sa)a Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-9AILE
47、RONS WIT_ TABSThe results of tests and the tes h conditions for models andairplanes having aileronswith tabs are given in table IE and infigures E1 to E53. Section characteristics of tabs on two low-dragairfoils are presented in figures E1 to E7. Characteristics ofailerons with tabs on a number of s
48、emispan and full-span modelsare presented in figures E8 to EA6. A fairly large range of wingsections, tab chords_ tab spans, aileron chords, and.aileron balancesis covered A fair amount of data for tabs on ailerons with thickened andbeveled trailing edges is included. Tabs on such ailerons, unfor-tlmately, are most effective in producing aileron hinge momentwhen deflected in the same direction as the aileron. Figure E30shows a decrease in tab effectiveness 8Ch/_5 t with increase intrailing-edge angle.Data from flight tests of an aileron equipped with a springtab (fig. EAT) are
