1、C7-DcCx.“RESEARCH MEMORANDUM -#EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF PLAN-FORMTAPER ON THE AER.0DY7WMIC CHARACTERISTICS OFSYMMETRICAL UNSWEPT WINGS OFVARYING ASPECT RATIOBy Edwin C. AllenAmes Aeronautical LaboratoryMoffett Field, Calif.NATIONAL ADVISORY COMMITTEEFOR AERONAUTICSWASHINGTON RECE
2、IPT SVWNUR!May 29, 1953 REQUIREDProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. . i*.,l.b!L.lg#L).,. . _- .r.-r.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TBCH LIBRARY KAFB, NMID.NACA RM A53G19
3、NATIOJUUADVISORYCOMMITTEEFOR.A3H30NAUTICS. RESEARCH MEMORANDUMEXPERIMENTAL INVESTIGATION OF THE EFTECTS OF PLAN-FORMTAPER ON THE AI?30DYNAMICCHARACTERISTICS OFSYMMETRICAL UNSWEFT WINGSVARYING ASPECT RATIOBy Edwin C.AllenOFsuMMARYAn investigationwas made to determinetauer on the aerodynamic character
4、istics ofthe effects of plan-forma series of sytmnetricalunwept wings hav=g thicknesses of 8-percent chord. The wings weretested in combination with four different bodies ofrevoluticm over aMach number rsnge from O. to 0.94 with a corresponding Reynolds numberrsnge from 2.58 miion to 5.90 miion- The
5、 lift, drag, and pitching-moment characteristics are presented for wings having aspect ratios of22 3 and k and taper ratios of 0.20 to 1.00.The drag-divergenceMach number was unaffected by taper for a con-stant aspect ratio. The msximum lift-drag ratio increased when thetaper ratio was reduced from
6、1.00 to either O. or 0.20 for the aspectratio 4 wings.INTRODUCTIONA great number of data axe available on the aerodynamic character-istics of tapered wings at high subsonic speeds; howevery these data cu?edifficult to correlate because of the differences in testing,techniquesused. It is the purpose
7、of this investigation to provide comprehensivedata on the effects of plan-form taper on the aerodynamic characteristicsof a family of syzmnetricaljunswept wings.Nine wings, in all were investigated, three aspect ratio 4 wings.having taper ratios of 1.00s 0.502 and 0.20; three aspect ratio 3 wingshav
8、ing taper ratios of 1.00, 0.60, and 0.33; and three aspect ratio 2. wings having taper ratios of 0. The profiles of auaE2!#Provided by IHS Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 NACA RM A53c19wings Were the NACA 63AO08. The wings were tested in ccxnbinat
9、ionwithfow different bodies of revolution to help differentiate between theeffects of taper and wing-body interference.ACDc%CLcmDMMDsvbccqYaNOTATIONb2aspect ratio, Bdrag coefficient, drr 3.25 inches,downstream from the base of the bodies, thenthe principal dimensionsare shown in figure 1.shown in fi
10、gure 2. Thefor a distance of 18 inchesenlarging conically to aQ!EEm.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 NACA RMA53C19diameter of 5.00 ches at a distance of inches downstream from thebase of the bodies. The aerodynamic forces and moments
11、 were measured bymesms of a strain-gage balsmce mounted within the bodies.TESTS AND PROCEDHThe aerodynamic characteristics of the bodies and the wing-bodycombinations were investigated over a Mach number range from O. to0.94. The variation of Reynolds number with Mach number for the various.wings is
12、 shown in figure 3. The angle-of-attackrange was from -6 to18 except where buffeting, tunnel power ltiitations, or structuralstrength of themodel reduced the upper limit.of the range.The test data have been reduced to standerd NACA coefficient formand have not been corrected for base drag. Base pres
13、sures of the fourbodies were measured and are presented in coefficient form in table I.A base drag could be computed from the base areas of the bodies aud thedifference between the measured base pressures and the free-stream staticpressure. For the aspect ratio 4 wings on th small body (finenessrati
14、o 9), this base drag coefficientwould be.0.0007 at low lift coef-ficients and Mach numbers up to 0.92. ,- Constriction corrections were applied tg.the tunnel-empty calibra-tion according to the methods of reference 1; The data were correctedfor tunnel-wall effects in the manner described in referenc
15、e 2.There was an interaction of the normal forceand pitching momenton the chord-force component of the balance. Since this interaction didnot vary systematicallywith lift or pitching moment and was not alwaysconsistent, no correction could be properly applied. It is believedthat such a correctionwou
16、ld not have chsnged any of the drag coeffi-cients by more than *O.OO1O, and its main effect would have been todecrease slightly the rate of change of drag coefficient with lift coef-ficient.RESULTS AND DISCUSSIONThe lift, drag, and pitching-moment characteristicsof the wing-body combinations are pre
17、sented in figures 4 through 13.The variation of drag coefficientwithzero lift, is shown in figure 14. The Machat zero lift (Mach numbers at which dCD/dM.-=.-.Mach number, measured atnunbers of drag divergence= 0.1) for the wings in .Provided by IHSNot for ResaleNo reproduction or networking permitte
18、d without license from IHS-,-,-.NACA RM A53C19 5combinationwith the body having a fineness ratio of 12 are tabulatedbelow:Aspect Taper%ratio ratio4 1.00 0.85a715O .85:.20 .853 1.00 .863 .60 .863 a71 332 1.00 :2 .71 .892 a71 50 .88The drag-divergenceMach number can be seen to be essentiM.ly umchanged
19、by taper for any one aspect ratio and was also found to be independentof the body geometry. With a reduction in aspect ratio, the Mach number. of drag divergence was increased slightly.For all the aspect ratio 4 wings, taper had little effect on theminimum drag coefficient (fig. 14) below the hag-di
20、vergence Mach number,with the exception of the wings in combination with the body having afineness ratio of 12. No logical explanation could be found for thedifferences in the minimum-drag values of these combinations. Above thedrag-divergenceMach number, decreasing the taper ratio caused a reduc-ti
21、on in minimum drag coefficient. For the wings of aspect ratios 3 or2, the apparent differences in minimum drag coefficient due to taper aremainly due to the differences in wing area relative to body size. Thewing srea not only varied with aspect ratio, but also varied with taperratio for the tigs of
22、 aspect ratios 3 and 2. If the body drag coef-ficients (fig. 15) are based on the respective wing areas and subtractedfrom the total drag coefficients for these wing-body combinations fromfigure 14, so as to give effectively the wing-plus-interferencedrag,it is found that the minimum drag coefficien
23、ts are about the same for alltaper ratios throughout the Mach number range.Figure 16 shows the variation of the drag-due-to-liftparameter(ACD/C 2, with Mach number overka lift-coefficientrsnge from O to 0.45.Taper ad some effect on this parsgeter, but these effects followed no.Provided by IHSNot for
24、 ResaleNo reproduction or networking permitted without license from IHS-,-,-6 NACAm A53c19consistent trend. This parameter increased with decreasing aspect ratio ._and was independent of body shape for any one aspect ratio.The variation of lift-curve slopes, at zero lift, with Mach numberis shown in
25、 figure 17. For the aspect ratio 4 wings, the taper ratio0.20 wing had a lower value of lift-curve slope than either the taperratio 1.00 or O. wing up through a Mach number of O.gO. The lift-curve slopes of the taper ratio 1.00 and 0.50 wings did not vary system-atically with taper. The lift-curve s
26、lopes decreased with decreasingaspect ratio; however, for any one aspect ratio, body geometry had noappreciable effect on lift-curve slope.The variation of the lift-drag ratio with lift coefficient for theaspect ratio 4 wings in combinationwith the small body having a fine-ness ratio of 9 is shown i
27、n figure 18. The wings of taper ratios O.and 0.20 exhibit a higher maximum lift-drag ratio than the taper ratio1.00 wings for all the bodies in combinationwith the aspect ratio 4wings. The effect of reducing the taper ratio from 0.50 to 0.20 on themaximum lift-drag ratio was not consistent and of sm
28、all magnitude.M-urn lift-drag ratios of the wings of aspect ratios 3 and 2 could notbe justly compared because of the chges in wing area with taper forthese aspect ratios.Figure 19 shows the variation of the pitching-moment-curveslopewith Mach number at zero lift. It should be noted that slopes ares
29、hown even for those cases in which the curves were nonlinear. At zerolift the effect of Mach number on the aerodynamic-centerposition wasalmost unchanged by variation in taper ratio for any aspect ratio, butthe variation of aerodynamic-centerposition with Mach number was reducedby reducing the aspec
30、t ratio.CONCLUSIONSFrom the tests of several wings, in combinationwith four differentbodies of revolution, the following conclusions can be drawn with regardto the effects of taper and aspect ratio:1. Effects of plan-form taper(a) The drag-divergenceMach number is essentiallyunchanged for any one as
31、pect ratio.(b) The lift-curve slope did not vary systematicallywith taper ratio.(c) The effect of Mach number on the pitching-moment-curve slope at zero lift is unchanged for any one.“.raspect ratio._.:-.-.:Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS
32、-,-,-NACA RM A53C19 7(d) For the aspect ratio 4 wings the maxtium lift-drag ratio increases when the taper ratio is decreasedfrom 1.00 to either 0.50 or 0.20. .2* Effects of aspect ratioThe drag-divergenceMach rumber and the drag-due-to-lift parameter increase with decreasing aspect ratio;whereas”,t
33、he lift-curve slope and the variation ofaerodynamic-centerposition with Mach number decreasewith decreasing aspect ratio. All these effects areconsistent with trends predicted by theory.Ames Aeronautical LaboratoryNational Advisory Comittee for AeronauticsMoffett Fieid, Calif.REFERENCES1. Herriot, J
34、ohn G.: Blockage Corrections for Tlrree-Dimensional-FlowClosed-moat Wind Tunnels, with Consideration of the Effect ofCompressibility. NACA Rep. 995, 19X. (SupersedesNACA RM A7B28)2* Silverstein, Abe, and White, James A.: Wind-Tunnel Interference withParticular Reference to Off-Center Positions of th
35、e Wing, and to. the DownWash at the Tail. NACA Rep. 547, 1935.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-mTABLE 1.- BA8E Pm88uRE coEFFIcLE19TBdy of - body Of I#w2 body Offineness ratio 12 ftieness ratio 9 fineness ratio 9cylindrical. bdy1 1 1a a
36、, deg2-.034 -.034-.034 -.034-.034 -.034-.034 -.034*.045 -.045 -.045 -.051.0510-.017-.034 *.033 .033.026 .ofX.026 .026-.051-.ol-.051 *-.051 -.034 -.op -.051 -.o -.034 .86 .051.osq. +. + + +$%:?wfi .+():%+. -+IKE + + + +EJjs.fi -*.+&;: *. + .+. . . J. . . . -_. . - - - -. -4 A NAr A All umenslonsm mcn
37、es excepr us rwfuu.-wz=-Figure /.- Wing und j4j44444. . . 0 .80 . 4 .86 .88 .80 .92 .84Lo.8.6.4.20-.2-.4-.6 .08 .04 0 -.04:08 Pitching-moment coefficient, CmCm Of 4 $54 JJ44444for Mof 0.40. 0 .70 . 0 . 4 .86 .88 .80 .92 .94(0) Taper ratio /.00.Figure 4.- The lift, drug, and pit thing-moment characte
38、ristics of theaspect ratio 4 wings in combinufion with the body having u finenessratio of /2.-w . . .”.-.-i.-.-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-:.NACA RM A53C19 *7A 13._ .-.f.o.8.6.4.20-.2-.4-.6-8 -4 0 4 8 /2 /6 20 Angle of attack o,
39、uegQof(?j J44444j4forhi of 0.40. 0 . 0 .80 .84 .86 .88 .80 . 2 .94for/.0 .8-.4-.6 0 .02 .04 .06 .08 ./0 ./2 .14 ./6 .18 .20 Drag coefficient, CDdbbbbbbbbbCD of of 0.0 .t50 .+0 .4J44444J4farM of 0.40.60 . 0 .80 .84 .86 .88 .90 . 2 .84.Lo.8.6Q-.-.4.3u .2s;0.s -.24-.4-.6 0 .02 .04 .06 .08 ./0 ./2 ./4 .
40、16 .18 .20 Drag oaefflcient, CDGDof+c)b+b(+efor M of 0.40.60 .70 .80 .84 .66 .8S .80 .92 .94Lo.8.6.4.20-.2-.4-.6 .08 .04 0 Y04 Y08 Pitching-moment coefficient CmCm Of 4 J44444444for Afof 0.40. 0 .70 .80 .84 .86 .88 .80 .92 .94(c) Taper ratio 0.20.F/gure 5.- Concluded.Provided by IHSNot for ResaleNo
41、reproduction or networking permitted without license from IHS-,-,-18forLo.8.6.4.Po-.2-.4-.6/.0.8.6;g$:OLUJ 444444., , 0 . 0 .84 .86 .88 .80 .9P .94(0) Taper ratio /.00.Figure IQ- The lift, dreg, undpitching-moment characteristics of theospecf ratio 2 wings in combination withraiio of /2.fhe body having u fineness.-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
