NASA NACA-TR-800-1944 Effects of small angles of sweep and moderate amounts of dihedral on stalling and lateral characteristics of a wing-fuselage combination equipped with partial.pdf

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1、.REPORT No. 800EFFECTS OF SMALL ANGLES OF SWEEP AND MODERATE AMOUNTS OF DIHEDRAL ONSTALLING AND LATERAL CHARACTERISTICS OF A WING-FUSELAGE COMBINATIONEQUIPPED WITHSUMMARYPARTL4L- AND FULL-SPANBy JDROW TEPLITZTe8ts of a wing$ueelage combiruu%nincorporatirq NACA66-seriee airfoil sect% were conducted i

2、n the NACA 19#ootpremure tunnel. The ?k#88ath eweepfonoard reduced the eective dihedral and inimu.eed theadver8ee$ect of jfap dejteciion. More famrable WLriationeofe$ective dihedral 55 al .1025 28 .cmThe changes in Reynolds and Mach numbers are believed tobe sufficiently small that the results may b

3、e compareddirectly.COEFFICIENTS AND SYMBOLSThe coficients and symbols are defined as follows:c.c.c.cmc.c,a$rc+CwG=*6RlMwhere!2bscDYlMivL(wliftcm.ffkiet $*U coefEcient-/)lateral-force cmflicient (Y/S)pitching-moment coticient (M/i”E)yawing-moment coefficient (N/gi%)rolling-moment coefficient (L/qSb)a

4、ngle of attack with respect to fuselage referenceline, degreeaangle of yaw, degreesdihedral angle, degreesslope of curve of rolling-moment coefficient againstangle of yaw (ac,)slope of curve of yawing-moment coefficient ngainstangle of yaw (acn/a*)slope of curve of lateral-force coefficient againsta

5、ngle of yaw (acy/a+)control deflection, degreesReynolds numberMach numberdynamic pressure, pounds per square footwing span, feetwing area, square feet (normal sweep, 30.488sq ft; sweepforward, 30.611 sq ft; sweepbnck,29.722 sq ft)mean aerodynamic chord (1.920 ft)latmal forcepitching momentyawing mom

6、entrolling momentSubscripts -aileron;U 65-percent-spanr right1 leftmux maximumdouble slotted flapsRESULTS AND DISCUSSIONAll data are refereed to the stability axes, of which theZ-Efion20-percenf cner?;:;p=-”A.M finmmjtifmlif.n,bwn 2.0FIOURE 3,Ddd19oftlap+dkon on wfng-fnsdagemmblnat!on. Akon ti”vel,

7、up W fromneutral and down 15 fromnentml. (Dimensions are gfven h prcent of normal wing Cbnrd.)Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.470 wmORT NO. SOONATIONAL ADVISORY COMMITTEE FOR AERONAUTS(a) Front viaw.(b) Rwr tieW.nxrm Lm+mlage mmblnat

8、ionmormbdonMat .mP -m in NAOAlmt P* tel. .Xqmamt-smmdoublesbttai ML8rlaleatedb5”.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EFFECTS OF SWEEP AND DIHEDR4L ON STALLING AND LATERAL CHAR4fXERIS!HCs 471t20-percent chord line of normol sweepa75 Yukv h

9、nnion“Norm6 sweep “”L=L, ?MA.C.q5_- - -_l+.NUT : .M+- .C I J Fuse/oe reference line.I oI-1sWQepfOflWOrd- - -_.- M.A.C,23.165i- -6.6 L91i J 8we TG. R7seloae referenc9 /fne SweepbockLMA. C 23.165- -:J - -_ -34-1 n1? -P 1 -,-7 ference fie.-:IhOURE5.-SkeWmwtng dlegmm whereas, with the full-apan flaps de

10、flected, sweepforward showed a slightly higherEft+curve slope than normal sweep. Because the sectionprofiles were altered when the wing sweep was changed, theangle of attack for zero lift was changed with sweep. Sweep-back caused the angle of attack for zero lift to be shiftedpositively. Slightly hi

11、gher increments of lift coefficientdue to partial- and full-span-flap deflection were measuredwith sweepforwaxd. %veepback showed a slight reductionin drag coefficient at moderate and high lift coefficients.kcreasing the wing dihedral increased C- slightly.With partial- and full-span flaps deflected

12、, slightly lowerdrag was measured with the smallest dihedral.Pitching moment,As shown in figure 6, the slopes of thepitching-moment-cmflicient curves are practically unaffectedby small angles of sweep. These pitching-moment coefbientswere computed about center-of-gravity locations 25 percentof the m

13、ean aerodynamic chord behind the leading edge of themean aerodynamic chord and at a fixed location above thefuselage reference line. It should be noted that the introduc-tion of sweep on a particular airplane might have a beneficialeffect on the static longitudinal stability bemuse of an effec-tive

14、rearward shift of the aerodynamic center with respect tothe cents of gravity.Stall,+ltaUing characteristics generally became 1sssdesir-able as the wing was swept back. The effect of sweep on thestalling characteristics as shown by the tuft behavior is pre-sented in iigures 8 to 10. The efFect of swe

15、ep with flapsneutral is shown in figure 8. It is seen that the point ofinitial stall moved outboard with sweepbnck. In the con-figuration with sweepforward, stalling started at the wing-fuselage juncture and moved outboard; in the configurationwith normal sweep, stalling started at approximately 50

16、per-cent of the semispan whereas, with sweepbacli, stallingstarted at 60 to 85 percent of the semispan and spreadinboard and outboard.Stalling occurred in approximately the same manner whenthe 65-percentispan flaps were deflected (. 9). Strong in-flow over and ahead of the ailerons was noted in each

17、 sweepconfiguration.The eflect of sweep on the stalling characteristics with thefull-span flaps deflected is shown in figure 10. In the con-figuration with normal sweep and full-span flaps deflected, astalled condition extending to 85 percent of the semispanoccurred very rapidly. Stalling again star

18、ted at the wing-fuselage juncture on the configuration with sweepforwardand full-span flaps deflected. An almost sudden still overthe outboard 50 percent of the semispan occurred withsweepback.For the cordigurations with normal sweep and sweep-forward the flaps, which were stalled at low angles of a

19、ttack,tended to nnstall and remain unetalled throughout the high-lift range. Flow behind the flap brackets was always poor;in addition, though the flap breaks were sealed, stallingoccurred at the flap junctures.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from

20、 IHS-,-,-)FIOUBE6.VarIatlonof CD,a, and C. with CLforsavamlmvwpand nap mmlgoratlons. 1%.4.6.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.02R262422201.8G.1.6t$ /.4$ /,$,Wstilld C20ssf/ow h the :;:;: Intenmtkntly; ./,.J dkzb? C/ Umbw$ a75 c$w:$fy.

21、,;,;:,;,. .#olkdFmurm8.-6L9UdlagmmsforsovorfdswmpomlItlona 3fa=00;5.-0; lu4.5;R=3.6Xl JUSO.12,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.Normo/ sweepfi. ,/, , stoned./, , E!s!lcompletelysiol/ed8,M-M”;?.-; 1=4,6”;Rs3,1X1W M#O.10,k.d.Provided by

22、IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Normal sweepa=-Z8cL=/,26SweePfirwordn n Pa=-4,6*CL=/.49 a=/0./”cL=2.73 a=lk”cLn2.40 a=/4.3 a=/6.4*cLn2.50 G =/.6.9d d VSweepbockP 4 / ?.: I .W 4 7 ILhSlbuy hfcoaya=2.4” a-/0. 4”CL-2.00 CL=26/ a=12.6” a/3. 6“U 1CL=2

23、.7SLCL=277b l1 Lkwto/kd a75h Crossflow,h thu m%Jj Intermittently+1 Utiect?bn.fomows ,.,:,;,. Sh/ t.=fi” (drmped+Wrrmmndltlon);I-4.5”;R$s2SXl;Jf$s0.09.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EFFECTS OF SWEEP AND DIHEDRAL ON STALLING AND LATERA

24、L CHARACLTUUSTICS 477LATERAL CHAEACTEEISTIC9The results of the tests to determine the eflect of sweep onaileron control are presented in figure 11. Rolling-moment,yawing-moment, and lateral-force coefficients due to ailerondeflection have been corrected for model asymmetry. Theyaw-test data me prese

25、nted in figures 12 to 17 and cross plotsshowing the most signifhmt results are given in figures 18and 19.Effeat of flap deflection on 04.Deflection of the doubleslotted flaps mused anoticeable reduction in effective dihedral(fig. 19). For the normal-sweep condition, the loss in C% wasapproximately 0

26、.00066 or about 2%0 effective dihedral andwas affected only slightly by a ohange in flap span. Theeffect of partial-span split flaps on C% was feud to be n-gible (reference 2). It appears, therefore, that the effects offlap deflection on C4 depend upon the type of flap underconsideration. .Effeot of

27、 sweep on aileron effectiveness,-With the flapsneul, sweepback caused a reduction in aileron effectivenessamounting tQ approximately 10 percent, whereaa a slightincrease in aileron effectiveness was noted for the oonura-tion with sweepforward. There was little d.i.tlerenoeinaileron effectiveness wit

28、h sweep for the two arrangementswith flaps deflected. Little differences in yawing momentdue to aileron deflection with sweep were noted. Yawingmoment due to aileron deflection was adveme with flapsneutral, beoame favorable with partial-span flaps deflected,rmd was more adveme with the full-span fla

29、ps deflected.Effeot of geometrio dihedral on Cl.The variation indihedral edect 0% with dihedral I is shown in figure 18.The change in C4 per degree dihedral change averagedappro.xirnately 0.00026, which is the value predicted bytheory (reference 1).Effeot of sweep on CQ.AS shown in figure 10, sweeP-

30、back increaaed the eilective dihedral for all flap conditions.The increase in effective dihedral ailorded by the changefrom sweepforward to sweepbaok varied from less than 2for flaps retraoted and high speed to more than 9 for full-span flaps deflected and low speed.%veepback noticeably reduced the

31、loss in eilective dihe-dral caused by deflection of the full-span flaps. The lossdue to deflection of the full-span flaps averaged approxi-mately 40,”2ji0, and 1 for sweeforward, normal sweep, andmveepback, respectively. The combination of sweepfor-ward and full-span flaps deflected resultid in an e

32、ffectivedihedral of approximately 1.A further advantage of sweepback is shown by the factthat the effective dihedral increases with lift coefficient forall three flap conditions with sweepback. Inasniuch as theadverse effect of power on dihedral effect ordinarily increaseswith decreasing airspeed, a

33、 favorable power-off variationof C4 with 6!Z as shown by the sweptback wing would behigldy desirable. With normal sweep and sweepforward,U,t remained essentially constant over the C-range for thetwo arrangements with flaps deflected; with flaps retracted,however, a less desirable variation existed;

34、that is, C4 de-creased with incensing lift coefficient.Directional stability.A consistent increase in the un-stable directional-stability slope Ca$ of ,-the wing-fuselagecombination accompanied increasing chhedral. The in-s4311c-5 tip deflection, however, almostcompletely erased the eilect. Sweep ap

35、parently had noeffect on Cy+.CONCLUSIONSWind-tunnel teats of a wing-fuselage combination in-corporating NACA 65-series airfoil sections were made todetermine the effects of small angles of sweep and moderateamounts of dihed.rid on stalling and lateral characteristics.The following conclusions may be

36、 drawn from the results ofthese tests.:1. Sweepback caused an appreciable increase in positivedihedral effect; sweepforward caused a reduction. “2. The increase in dihedral efTect caused by sweepbackvaried favorably with air speed, in that it increased with lift coefhcibt.3. Deflection of double slo

37、tted flaps resulted in a notice-able reduction in effective dihedral; sweepback decreased andsweepforward increased this eifect.4. Sweepback moved the point of initial stall outboard andcaused a slight increaae in maximum lift caeflicient.5. Sweepback causd a reduction in aileron effectiveness ofapp

38、roximately 10 percent with tips neutral. With partial-or full-span tlaps deflected, sweep caused no noticeable ohangein aileron effectivenew.6. Standard theoretical methods for predicting the effectsof dihedral changes on lateral- and directional-stability de-rivatives appear valid and unaffected by

39、 changes in wingsection. For the”wing plan form used in the present tests,an increase in the lateral-stability derivative C+ of 0.00026per degree change in geometrio dihedrid angle was noted.Increasing dihedral increased the directional instability ofthe wing-fuselage combination.7. The effects of d

40、ihedral on the remaining aerodamiccharacteristics appeared to be unimportant. The presenttests indicnted a slight inorease in the value of maximum liftcmflicient with increasing dihedral. Increasing dihedralalso caused a slight increase in the value of the lateral-forcederivative Cr with flaps retra

41、cted; little effect was notedwith flaps deflected.LANGLEY MEORIAL AERONAUTIC LABORATORY,NATIONAL ADVISORY Commmr ED FOR AERONAUTICS,LANGLEY FIELD, vA., fi lb, 1944.WFERENCE1. Pearson, Henry A., and Jon=, Robert T.: Theoretiwd Stability andControl Charaotarietiea of Winge with Various Amounts of Tape

42、rand Twist. NACA Rep. No. 635, 1938.2. Bamber, M. J., and House, R. O.: JWnd-Tunnel Investiition ofEffect of Yaw on Lateral-Stability Characteristics. IFour .N. A. C. A. 23012 Wings of Various Plan Forms with and withoutDihedral. NACA TN No. 703, 1939.Provided by IHSNot for ResaleNo reproduction or

43、networking permitted without license from IHS-,-,-478 REPORT NO. 80 ONATIONAL ADVISORY COMMmEE FOR AERONAUTICSL412I.o.8.64.2 ii I I I Ill I I I I I I I I I 1I Iwfd I I I I2826I I I I I I I I I I II # , , , .I I I 0 Ill242220L81s1.4I 141 I I I I I I I I I I I 1 ?Pa75, 1 I I I I T1l-11“ “II ICll H 124

44、 -4 * ,2f6_04 D3 .02 .010. .Oi .04 “o .040 -J -2 -.3 -.4. zAngleof oifa%.% %.ZMW Z%zi%!Pit3%=.-w;a., =1P; d.l-gs; Rs3.lXl .U=O.1O.(0) aru-% a%dw; a., R=28XW = am.Fmm 11.Effeotofsweepon affemncontrol. r4.JV.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-

45、,-,-. . . . /Angle of, ye normalswrap; R-3.6Xl; fif=O.lZ. ,%coProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-,gI I I I I I I I I I I I I Ii? t.n, !a) (i)I II I , 1 I T,HIIIII III $L# J+-nocmnlsweep;Rz=3.IXK%sO.10._Provided by IHSNot for ResaleNo rep

46、roduction or networking permitted without license from IHS-,-,-3mw(8) a-6.4”, (b)a-2CY.hNRE 14,Variationof C., CI,CY,and CLwith # forthrw rllhotlralcondltlorw fu=6;8%=d.1-Z&; normalSWWP;lZ=$28Xl;iiI=O. 6+-; r=4.; RsL6xl; =o.Provided by IHSNot for ResaleNo reproduction or networking permitted without

47、 license from IHS-,-,-.q% I I I I I I I T8 .8 A4mdsweeplqm./i4_ Swep forwvrd7.2 1111 .3veenbuck I A;0 d L . L Or ,T (0) Liiliiii iii. iiiiilll t+Lb I I 1 1 1 1I5 10 15 20 25 -5 0 5 /0 /5 20 25 -5 0 5 /0 15 PO P5r. Angle of yti, Y, deg(a) ccq-OV. (b) U-lor. (o)a-O.W.-.FrouRlO,-V, cl, c%,C., aod Cl with # ort.brwSWOOPrandltbm J%-J.I=O”; -4.&; R3.lXIW 0.10.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.10 4 1 I 1 I I I.05 I I I I *l-.ullllllllu.+-rz.0It“k(a) a-6.i0. (b) .4.CP.F30UBB 17.Varia