REG NACA-RM-A50K27-1951 The effects of Mach number and Reynolds number on the aerodynamic characteristics of several 12-percent-thick wings having 35 degrees of sweepback and vario.pdf

1、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1 . - 4% CL . c XACA RMA50K27 NATIORALADVIS6 having 35 of aweepback. Six semispsn model wings were. tested: Three representing wings hav- ing an aspect ratio of 10, and three representing wings having a

2、n aspect ratio of 5. The streanrwise sections of the three wings of each aspect ratio were, the XACA 6ylA012, the HASA 64111312, and the NAcA 641612. According to simple sweep theory, the aerodynamic characteristics of SeCtiOnS perpendicular to the quarter-chord lfns determine the aerody- namic char

3、acteristics of a swept-back wing. The sections perpendicular to the quarter-chord khe of the wings investigated were approximtely 14 percent thick and had desigu.lift coefficients of about 0, 0.37, sad 0.73. Results of tests of airfoil sections reported in reference 3 have indicated that the additio

4、n of camber increases the msximum lift coef- ficient for airfoil sections having thickness-chord ratios of less than 12 percent, but that the effectiveness of camber in increasing the maxi- mun lift coefficient d-imin-ishes as the thiclmess is ticreased beyond 12 or 15 percent. For the 14-percenGthi

5、ck wings tested in the present Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-RACA RM A50E7 3 investigation, the increase in the maximum lift coefficiefit resulting from camber and hence the increase in the lift coefficient at which longitudinal ins

6、tability occurs should be significant but map not be expected to be as great as that which would be anticipated for thinner WfngB . The tests were conducted over a range of Mach numbers from 0.25 to 0.92 at a Reynolds nu valueof CD-x . lift coefffcient lift ( ) yr pitchivnt coefficient about axis pa

7、ssin; through the gusr- ter point of the -an a.erodynamTc chord pitching moment qs a pitch-ment coeffkient at zero lift aspect ratio Mach number s 0 Reynolds nunker semia= WWs =ea, square feet airspeed, feet per second lift-drag ratio lift ( iirag i - Provided by IHSNot for ResaleNo reproduction or

8、networking permitted without license from IHS-,-,-4 lWCA RM A50E27 a b speed of sound, feet per second span of complete wing masured perpendicular to the plane of symmetry, feet C chord, measured psrallel to the plane of s-try, feet a meanaerodynamk chord , feet q Y a aO P l-c dynamLc pressure, poun

9、ds per square foot lateral distance from plane of symmtry, feet angle of attack, degrees angle of attack for zero lift, d.egrees density of air, BlUgB per Cl and the other three represented w3ngs having an mpect ratio of 5 aml a taper ratio of approximately 0.7. Eachmodel had 39 of sweepback of the

10、quarter-chord line. The dilEinSiOIlB oft+ model8 83% BhCfW?l in fil333 1. The thiclmess distribution of the sections of each model was the sam3 from root to tip and there was no twist. The wing sections in p-8 parallel to the plane of Bymetry were the RAGA 65lAO12, the NACA 64lA312, muI the RACA 641

11、A6l2. The wings with these BeCtioIlB Will be referred to ti this report as the uncanibered, moderately canibered, and hQhlyca was fozmed by a haIf body ham a radius equal to the corresponding half thfclmess of the wing section. The models were constructed of steel. 5 0uterpoAions of the model wings

12、having an aspect ratio of 10 w near the maxlmumlift coefficient, it may be concluded that the effects of model distortfon were negligible. The increase of mximuu Uft coefficient at a Mach nuB with various amounts of caliber are presented in figure 14 for a %ch number of 0.25 and a Reynolds number of

13、 lO,QOO,OOO. The values of perti- nent aerodynamic parameters taken from the data of figure 14 exe pre- sented in the following tables: . , Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ll =At R, Parameter Design 0, wL/aa design CL “%nax aO (%L)des

14、ign k cm0 %ill (Lb), CLfor (L/b), 1 1 SPEYJT RATIO 10 Airfoil section NAC!A 651+2 0 ,075 -97 0 -.071 -moo6 -0032 32.5 .38 . . (fig. 4.) NACA 64lA3l2 0.25 l 5 1.24 -2.2O -.0000,000 indicates that, atthis low Reynolds number, camber caused marked improvement in the aerodynamic characteristics at high

15、lift coefficients. Such a comparison may be made from data presented in figure 16 which were obtaFned at a Mach number of 0.25. Inspection of these data reveals that, in addition to improving the maximum lift coefficient, camber caused increases in the lift coefficient at whfch static longitudinal F

16、astability occurred and reduced the drag coefficient at large values of lift coefficient. Comparison of the data of figures 7 through 12, whfch are for Mach numbers from 0.25 to 0.92 and a Reynolds number of 2,000,000, indicates that the improvements due to camber in the mqimum lift coefficfent and

17、in the lift coefficient at which static longitudinal W .72 As would be anticipated from the results of tests of 64-series aixfoil sections reported in reference 10; the drag-divergenoe Mach Ilumber was, in general, reduced by caliber. At Mach numbers less than that for drag divergence, the effeot of

18、 cm /i: 6jq - - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 0 4 8 I2 f6 20 .I2 .08 .04 0 04 0 04 .08 12 Angle of attack, U, deg Pitching-nwmeo f coefficient, c;, ckag coefficient, G . Provided by IHSNot for ResaleNo reproduction or networking p

19、ermitted without license from IHS-,-,-.2 I L -8 -4 0 4 8 I2 16 20 24 .I2 .08 .04 0 304 08 0 .04 .08 .t2 .16 20 I% Of attack, 0; deg pitching-nment coefficient, t ainW e, Drag coeff<, 6 (d) A, 4 a&fM se&w, 6+4Of2. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without licens

20、e from IHS-,-,-. -4 0 4 8 I2 I6 20 24 .04 0 04 108 0 .04 .08 ./2 ./6 .20 .24 .28 Angle of ottuck, a, deg Pitchhg-moment coefficient, C, Drag coefficient, CD Figwe 4- Continued Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_ 1 . I I I -.2 I I I I I

21、I I I I I I I I I I I llllllllllllillll I I I I I I I I I I . 11 ! 1 ! 11 11, B -8 -4 0 4 8 I2 16 219 24 .04 0 504 708 .112 0 604 m&W I2 .I6 20 24 Angle of ottmk,. u, dep Bag coeft?&nt, G pifchingmament coefficnt, qqj fl 4 5j otPhV.1 eedhn, &%?A 6qA6Y2. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-