1、RESEARCH MEMORANDUM LONGITUDINAL CBARACTERBTICS OF TWO 47. SPTBACK WINGS WITH ASPECT RATICE OF 5.1 AND 0.4AT REYNOLDS NUMEIERS UP TO 10 X 10 66 ,W By Rein0 J. Salmi and Robert J. CarroSd 2 u Langley Aeronautical Laboratory 0 Langley Air Force Base, Va. z d “9 . t .fi t ts NATIONAL ADVISORY COMMITTEE
2、 FOR AERONAUTICS WASHINGTON c March 30,1950 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-WCA RM L5OAOk By Rein0 J. salmi asd Robed J. Carroe A low-peed Inverrtigatian of the lcngitudinal aerodynamic charac- teristics of a 47-70 sweptback wing was
3、conducted in the Langley 1Ffoot preseure tunnel in order to provide laz-cale data cm relatively high- aspec-atgo sweptback wings. The wlng featured intemhmgeable - tips whidh prcwided aspect ratios of 5.1-and 6.0 with corre6-p- taper ratios of 0.383 and 0.33. Nkc 6-0 airfoil eectians were emglaged n
4、ormal to the 0.286 chord line. The data were obtained through a range of Reynold8 nunibera varying frcm approximately 1.1 X 106 to 10.0 X lo6 asd Mach nmbers of 0.06 to 0.25. The maximum lift coefficient increased slind 6.0 in; at moderate lift coefficients. The abrupt metable moment break can be at
5、tributed to sepaz-atian nem the tips. Figure 6 Micatea the preaence af _spanwise cross fl“ prior to the initial separatian. As the angle of attack wa8 increased, the S and, a shown by the plota of y1tcMn.g moment agaimt angle of attack- (figs. 4 and 51, the slope of the momazt curve becams negahive,
6、 thus LndicatFng stability at the masimam lift;. Some of the curve8 of pitching mcansnt agabst angle of attack for the high Reynolds nw to note that the pitc-t curve obtained at a Reynolds number of about 1.10 x lo6 exhibited an increase ln sta- bility prior to the unstable %rebly inboard of the tip
7、e. Lift Characterfstics Maximum lift coefficients of 1 .lg asd 1.20 were obtained at a Reynolds ntrmber of about 8.0 x lo6 for the aspect ratio 5.1 and 6.0 we, respectively. Figure 7 shows that the lift coefficinnts increased Brightly with increasing Reynoldi lLulziber in the range of Regnalde nmibe
8、r from a%out 2 .O X IO6 to 8.0 X IO6. A decrease in “ri, occurred When the Reynolds mer. was Fncreaeed to about 10.0 X I_gnolda nuniber of 6.0 x lo6 and approx3mately 0.03 at a Reynolds rimer of 3.0 x 10 6 . The lift-curve slopes were unaffected by roughness. Flgure g(b) ahowe that the roughnees caw
9、ed a canaiderable reduc- tion in the inflection Urt caefficient at a Reynolds nmber of about 6.0 X 10 but had a negligible effect at a Reynolds number of 3.0 x 106. The effect of the rarghnesa is eimilcr to the effect of a low ReynoliFB number in that the energy of the turbulent boundmy layer is red
10、uced sild se-paratim may occur at a lower anae of attack. 6 At a Reyn0ld.e number of 6.0 x 10 , the pitc-t curves were 6 lineax up to the Mlecticm Uft coefficient for both the smooth and rough configuratiane. The aerodynamic canter shifted fmward about 2.3 percent mean aerodynamic chord, however, wf
11、ien the roughness was added. A forward movamazit of the aerodynamic center due to roughness was also a;pparent at the lmr Regnolde number in that the slope of the moment curve gradually decreased. From figure 9 it can be seen that the effect6 of roug3mess on the drag rise correspond with the effects
12、 on the unstable momtmt break. The drag rise occurred at a mch lower lift coefficient for the rous rematned at an essentially con+rtant positiopl up to m0a“te lift cOeffici*ts. haainp-eage eeparatian near the tipe than caused an abrupt unstable break. A laxge Increase -Ln the Fnflecticm lift coeffic
13、ient (llat coefficient at nhich abrupt pitchin-t brealr occure) occurred between Regnolde number8 of about 2.0 X lo6 and 4.5 X 106. MaxFmLrm. values of the Inflec- tion lift coefficients for the wpct ratio 5.1 and 6.0 were approxlmatew 0.86 and 0.82, respectively. 3. A vortex flow was ahown to exist
14、 an the whg. The vortex flow affected the pitch-t characteristics,at a Reynold8 number of about 1.10 X 106 but its effect8 were minimized by tip stm at the higher Reynolds nunibers. 4. The maximmliftilrag ratio8 were obtained at a lift coefficient -of about 0.25 and were approximately 25.6 and 27.8
15、for the aepect ratio 5.1 and 6.0 wfngs, respectively. . Lanaey Aeranautical Laboratorg National AdviBorg Committee for Aeronairtics Langley Air Force Baae, Va. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EACA RM L5OA04 9 3. Shortal, Joseph A., an
16、d Maggin, Bernard: EXfect of Sweepback and. Aspect Ratio cm Langitudind Stability Cha3.acteristics of Wln;s at Lar SpeeaS. NACA TN 1093, 1946. 4. DeYaung, John: 5oretical AdditirrnFtl Spas hadfng Chmacteris.tics of Wings with Arbitrary Sweep, Aspect Ratio, and Taper Ratio. NACA TN 1491, 1947. 5. Fit
17、zpatrick, Jazass E., anO- -4- -A- -b; -a-. CD Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-20 NACA RM L50AO4 .aB cm O -.08 .“ . I. R=Z.0X/06 A = 5.1 .08 GO 708 0 .4 .8 LP 4 Figure 6. - Stalling characteriatics of the 47.7O sweptback winge with asp
18、ect ratios of 5.1 and 6.0. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-21 I. 4 I. 2 1.0 -8 .6 -4 .2 0 0 2 4 6 8 /O /2d R Figure 7.- Variation of the maximum lift coefficient and the inflection lift coefficient with Reynolds rider for two 47.7“ sw
19、eptback wings of aspect ratios 5.1 and 6.0. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-22 28 24 20 8 4 0 NACA RM L5OAO4 Figure 8.- Lift-drag ratios of two 47.7O sweptback wing of aspect ratios 5.1 and 6.0 at Reynolds numbers of 6,030,000 and 5,8
20、x),OOO, respectively. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. 1 1 I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1.2 1.0 .8 .6 .4 CL .e 0 -. 2 -4 ./2 .08 .04 0 -.W 708 -./P cm (b) CL plot
21、ted against C,. Figure 9.- Continued. I . . . . . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-d L p 1.P .6 “4 0 .04 .OB . IP -16 20 .24 .28 .3P .36 ,40 -4.4- .48 .5P 0 .04 -08 J2 .I6 ,ZO 24 -28 .32 .36 .40 .44 .48 .5P CO (c) cL plotted Wnst CD. Figure 9.- Concluded. . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. i I f Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
