1、“ RESEARCH MEMORANDUM AERODYNAMIC CHARACTERISTICS 0F.A 45 SWEPT-BACK WING WITITASPECT RATIO OF 3.5 AND NACA 2S-50(05) -50f05) AIRFOIL SECTIONS Anthony J. Proterra Laggley Memorial Aeronautical Laboratory Langley Field, Va. CLASSIFICATION CANCEL “ . c NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS. Prov
2、ided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ERRATUM - NACA RM NO. 711 i ! I i Provided by IHSNot for ResaleNo reproduction or networking permitted witho
3、ut license from IHS-,-,-UNCLASSIFIED NATIONAL ADVISORY CCMMInEE FCLR AERONAUTICS “ BY ethony J. Froterra SUMMARY The results of an investigation to deternine tho aerodynamic characteristics at high Reynolds numbere and low Mach IlIHnbers of a 45 swept-back wing with aspect ratio -3.5, tqer ratio of
4、0.5 and circular-arc seations are premnted in, this report I Scale effects were investited at Reynolds nunibore ranging from 2.1 X 106 to 8.0 X 106; the effects of yaw were nvestigated at a Reynolds number of k.1 x 106. The results indicate that the wing has goor characterfstics from low-speed consi
5、derations. The wing kaa a maximwn lift of attack. Tho longitudinal stability is neutral up to a lift coefficient of approximtely O3 and increases above this value to a lift coefficient of approxbately 0.5. Between 8 lift coefficient of 0.5 and maximum lift cosfficient Ch the wing ie longitudinally u
6、netable but at Ch the wing has a diving tendency. The effeat5ve dihedral is positive. up to a lift coefficient of 0.45 but is negative above this value. The wing has neutral directional stability up to a lift coefficient of 0.43 and is directionally unstable at hieer lif -b ooefficients The lift, dr
7、ag, and pitching-moment coefficients are almost unaffected by variations in Reynolds number. - coefficient of approximately 0.87 ana has high drag at high angles INTRODUCTION L The proposed we of swept and, low-aspect-ratio wing plan form and blconvex profiles to minimize compressibility effects at
8、transonic scale aerodynamic ChWaCtri6tiCs of these wing6 at low Mach numbers. I arid supersonic speeds has omphasized the need for data on the fa- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0- A positive when the - moment tends to retard the rig
9、ht wind pmel L rolling moment abaut the a foot-pounds; positive when the 4j moment tbds to raise the left win;- panel 3 E distance from leading edge of root chord to buarter- chord 4 Reynolds nuniber (F) of the mean aerodynamic chord (9.03 ft) a angle of attack msasured in phm of symmta, degrees f a
10、ngle of yaw, positive when right wing panel is ratarded, degrees - y kinematic viscositr, square feet per second “ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 - MACA RM NO. 711 shown in fi- 3 The WFng kas an ane of sweep of 45* at the quarter-c
11、hord line. The airfoil eections perpendicular to the 50-percent chord line are circw-arc sectione and have a maximum thichese of 10 percent at the W-percent chord. The mdel has an aepect ratlo of 3.5 and a taper ratlu of 0.5 with the wing tips slightly rounded. The has no geometric dihedral or twiet
12、. The wing vas Qonatructed of lb-inch aluminum sheet reinforced by steel channel spars. The wtng surfaces wore about the equivalent in roughness to canvantianal thin dural sheet cmstruo.tion with dimpled skin and unfilled flush rivete. The viw construction was extremely rigid and it is not bslievod
13、that deflections of any appreciable magnitude occwed during the teats. The Jet-boundary ekPect6, the blocking effects, the stream , alinement, and. the taree cawed by the wins dupport struts m6e calculated for the zero yaw condition and were used for correcting the angles of attack, the longitudinal
14、-force, %he Wft, and the . pitching-nwnt coefficients of the data etalled first. Tuff. . . . observations (fig. 8(b) also indicate the. sarne resul.t3s. .I “. . . At a ILft coefficient up to 0,.3 ;ory t.0 those that have been ob%ained. with swept-back vin havine con- ventiml a9rfoil eectLons. It is,
15、 therefore desirable to take note of same of the flow phenmena that produce these rerjulte, especially since they are.beUeved to be chay.acteristic of hi whereas, a canventional section nharacterized by 2,- zrr*.+r+ an initial separation OGCUTB aZ; a much hi q an Wfng and incr4iasing the sweep of th
16、e trailing TKI. Contrary to the resulte obtsined win! wlslga of conventional airfoil 8ection8, decrewlq the sweep of the biconvex win6 does not alleviate the s.t;all EFreciably, and Ln fact in ome stieep ranges may, as in thin cam, even amante it. LikewiEe, inCreaf3iw the sweep of the biconvex wing
17、may improve the flow conditiana by a flow meohnim sMhr to the large vortex observed an tho DM-1 glider aftm the sharp leading eQes were added (ref eronce 3) The generally low effective dihedral -of this wing and the early change from positive to negtive effec.t;ive dihedral then appears to reeult fr
18、om the combined effects of these chanms In .the flow due to the eideslip anti the early tip stall., The tuft surveys of f igre 8 show these effects qui39 clearly. Although hieffective dihedral hat3 been me of the moet seriosw problem ccmfrontine; the desimer attempting to me swept-back wingsI the lo
19、w effective dihedral cif this wing is by no meane cansidered a soLution tothe problem, because it would probably be .almost impossible to maintain adequate lateral control by conventional methods after the tlp had begun to stall and becawe of the longitudinal tmtakiUty eqmriencsd at moderate and hig
20、 overcone SUMMARYOFS . The resalts of force tests of a 45 sweions Zn the Langley full-scale tunnel are summarized 8s follows: 1. From lofurrjpeed considerations, the WLng has poor character- ietfcs me inc is neutraw stable up to a let coefficient .of approxbately 0,3 and abo increases, Provided by I
21、HSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-HACA RM No. L7CU “-m 9 4. The ving has hi A = 0.5; = 00. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- . . . . . . - . . . . . . . . . . . . . . . . . .- . . . .
22、. . . c , , “gure 4.- Continued. * .I . . ,I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MACA RM No. L7Cll Fig. 4c (c) C, versus CL . Figure 4. - Concluded. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
23、 IHS-,-,-. . . . . . . . . . . . . . . - . . . . . . . . .- . . . . . . . . , . . . . . . Figure 5.- Effect of Reynolds number on CL of a 45 swept-back max wing. A = 3.5; h = 0.5; $ 0. c . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM No. L
24、7Cll Fig. 6a . * Figure 6. - Variation with angle of yaw of the aerodynamic characteristics of a 45 swept-back wing. A = 3.5; A = 0.5; R = 4.10 x IO6. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Fig. 6b NACA RM No. L7Cll Provided by IHSNot for Re
25、saleNo reproduction or networking permitted without license from IHS-,-,-NACA RM No. L7C11 Fig. 7 * Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Fig. 8a NACA RM No. L7Cll (a) + = 00 Figure 8.- Tuft studies for a 45O swept-back wing. R = 4.10 x lo6
26、. “ . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RNL No. L7Cll Fig. 8b (b) * = +3.70. Figure 8. - Concluded. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-“ . . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
