1、:a*-4THENATIONALADVISORY COMMITTEEFOR AERONAUTICSTECHNICAL NOTE 2229EFFECT OF ENDBy John M. RiebeONandSWEPT WINGS AT LOW SPEE:James M. WatsonLangley Aeronautical LaboratoryAir Force Base, VaWashingtonNovember 1950w- -r”- -n!, ,-,1, ,L. l.-. . . J l= .- , :. . . . . . . . . . .- - . . . . . .,. : - ”
2、-”- -. :. ., .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-# IIWILIBRAtSYiAPB, PM“.IllmllmlllulllulloI?ATI(INALADVISORY COMMITTEE FOR AERONAUTICS 0Clb50blmCHNICALNOTE2229THE D?FECTOF END PLATES ON SWEPJ!WINGS AT IOW SPEEDBy John M. Riebe and Jsmes
3、SUMMARYM. WatsonAn investigationwas made in the Langley 300 MPH 7. by lo-foot tunnel to determine the effects of various sizes end shapes of end plateson the aileron characteristicsand on the aerodynamic characteristicsinpitch end yaw of a tig of aspect ratio 2 with no taper and a sweepbackof 450 au
4、d of a wing of aspect ratio 4, taper ratio 0.6, and sweepbackof 46. p. Free-roll characteristicswere obtained with two end-plateconfigurationson a wing of aspect ratio 3, taper ratio 0.6, and asweepbackof 350 h order to determine the effect of end plates onwing -damping in roll.The addition of the e
5、nd plates to the swept rigs increased thelift-curve slope, reduced the maximum lift-drag ratio, generallydecreased the maximum lift coefficient, end increased the longitudinalstability slightly in the low lift coefficientrange.The variation of wing effective diQedral with lift ,coefficientwas.reduce
6、d by increase in end-plate size. The effective dihedral at zero “lift could be changed from positive tb negative by lowering the endplates. The directional!.stability of the swept.wings was ticreased withticrease in end-plate area aud with rearward movement of the end plates.The flap-type aileron en
7、d spoiler-aileroneffectiveness increased with the addition of end plates to the swept tigs; however, the increaseof the wing damping in roll may reduce the ro.11.inneffectivenessfor someend-platejconfigurateions. In addition, end plates located bekw the wingchord line reduced the adverse yaw of flq-
8、type ailerons.Theoretical.and experimental.tivestigati as csn be seen from reference 7,there is little effect of sweep on the.jet-boundsryeffects. Blockagecorrectionswere applied to the test dsta by the method of reference 6.The data have been corrected for the effects of the motion-ofVariation ofVa
9、riation ofVariation ofVariation ofVariation ofsize . . .Vsriation ofsize . . .ACtith end-plate size. . . . . . . . . . . .15AC however,.a few tests * at0 angle of yssishowed that small angles of yaw had little effect onthe incrementalvalues of Cl , , . , . . .,. .,#,.Provided by IHSNot for ResaleNo
10、reproduction or networking permitted without license from IHS-,-,-IucATN 2229obtained fromobtained from.9the experntsl- data of this investigation and thatunswept-w5ng end-plate theory (reference7) with the use“of reference 8 shows good agreement (fig. 15). It can be seen tl forvalues eater them 0.5
11、, however, the unswept-Mng data indicate thatthe chsnges tn AC% end A/A are less thsn those predicted by thetheory of reference 7. It would be expected, therefore, that furtherticreases in end-plate size on swept wings would give further increasesh C%, but that the fncrease6would probaly be less tha
12、n those pre.dieted from the theory of reference 7. Wing taper ratio might beexpected to have an effect on A% for a given value of h/b for ,wings having fairly him tap. The results of this tivestigationinticate that the effects of ts however, the values of (L/D)E generally decreasedwithincreases in e
13、nd-pkte area ratio. inspection of figure U. shows that(L/D)E OCCUrS at lift coefficientsless then *out 0.3. me resflts(fig. 17) indicate that unless the end-plate drag is very mall noappreciable gains in (L/D)E can be expected since there is increase in dreg coefficients due to the end plate for lif
14、t coefficientsbelow 0.4. .a71. - ,. . . . - .-: . - .- .- -. ” - . . , . . .-. .-. .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.NACATN 2229 IL.Longitudinal stability.- The addition of end plates to the swept-back wing of aspect ratio 2 resulted
15、in an increase in the longitudinalstabilityof the wing .inthe 0.1 to 0.65 lift-coefficientrange (fig. U).The shtit in odynamic center varied almost linearly vith end-platearea, the aerodynamic center moving back out 5 percent mean aerodynamicchord as the end plate was increased to = 1. Variations in
16、 red-plateshape and locationhad only small effects on the longitudinal stility.The increase in longitudinal stability of the sweptbackwing probably isdue to a shift of the center of pressure outbosrd as a result of restraintof flow about the wing tip with the end plate in place.Data obtained with th
17、e sweptbackwing of aspect ratio 4 (not pre-sented hereiu).showed similar results.Lateral StabiliEffective d3hedral.- The rate of chsnge of effective dihedralwithlift coefficient at low lift coefficients ac/bCL was reduced withincrease in end-plate area on both the sweptback tigs of aspect ,ratios 2
18、end 4 (figs.12, 19, and 20). The reduction in th s effect was reasonably tidependentof end-plate locationmove end/orbelow the wing chord line. This fact is indicatedby thedata of fQures 21 and 22, which are for a lfit coefficientof 0.5 andalso generally applied to the variation of Cn* with end-plate
19、 sreathroughout the lift-coefficientrange (fig. ld). The data of figure 21also show en effect of forward and rearward location of a given end-plate mea on the values of Cn*; this effect results from a change hthe moment erm between the wing center-of-momentposition end the centerof pressure develope
20、d on the end plate at sn#.es of yaw.Side-force coefficient.- The variation of CyW with CL wasnegligible throughout the lift-coefficientrange for all end-plate con-figurations on the wing of aspect ratio ? (fig. I-2). Increase in end-plate size resulted in larger positive changes of CY* for the swept
21、wings of both aspectpendent of end-plate.ratios 2 and 4; this effect appe however, the wtng dsmping-in-rollcoefficient Czp may increase at a greater rate with the addition ofthe end plates than did C5a snd thus result in lower values of pb/2V.In order to investigatethis effect, a.few static-roll and
22、 free-to-rolltests were made cona roll rig (fig. 7) of a 350 sweptbackwing of aspectratio 3 (fig. 6). One of the end-plate configurationstested on the .35 sweptbackwing was similsr to that tested on the 45sweptbackwingof aspect ratio 2 with which the lsrgest value of %a was obtained.For the other en
23、d-plate configurationinvestigatedon this wing, tieupper half of the aforementionedend plate was removed. The flap-typeaileron on the 350 sweptbackwing did not extend to the wing tip;therefore,no CUtOUt was made h the-end pte to P-t tie eron todeflect - as was necessary on the 45 sweptbackwing of asp
24、ect ratio .The plain-wing data for the 350 this reduction in (pb/2V)avaried little with end-plate area (figs. 25 and 26) for these two end-plate configurations. wo cza increasedwith end-plate area,the damping-in-rollcoefficient Czp ticreased at about the ssme rske,as shown by values of Czp computed
25、from the data of figures 24 to 26,(-O. 305 for the plain wing, -0.365 for the wiug with the sweptba endplate located below the wing chord line, and -0.436 for the sweptbackend plate located ove and below the wing chord Me). The Czp VSIL1.leswere determinedfrom the relationshipC2 c2aC2P=- -pb/2V= (pb
26、/2V)aThe values of Czp were computed for an angle of attack of 6.5 inasmuas no static rolling-moment data were obtained at any other angle ofattack. The increase in the values of CzP was proportional.to end-plate area; that is, dodd.iug the end-plate area about dcnibledtheficrease in Czp. .As noted
27、previously, the triangular-shapedend plate of smaller areathan end plates of.other shapesmay be utilized to obtain a given increasefi c2a (fig. 23). Because the dsmping.inrolJ.is shown to vary with Jend-plate area, the triangular end plate should result in a smsller incre. ment of Czp. It may theref
28、ore be possible for low-aspect-ratioswept-back wings with end“platesof this type to have *out the ssme or.largervalues of (pb/2V)a as those of plain wings.Unpublished data from a free-roll investigationmade in the Langley300 MPH 7- by lo-foot tunnel actually did show a very slight increase (pb/)8a a
29、 - ad plate was attached to a sweptback-wingmodel with the end-plate area mncentrated near the aileron. The wingreceivingbenefits from the addition of end plates - such as increasedlift-curve slope or reduced variation of effective dihedral with liftcoefficient - would thus not be penalized by reduc
30、ed rolling power. .-. - -. -,-. - . .- :. -. - - -. -., ., .,- - . . .- -. -. . .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN 2229CONCLUDINGREMARKSAn investigationwas made in the Langley 300 MPH 7- by lo-foottunnel to detezmdnethe effects o
31、n aileron characteristicsand on wingcharacteristicsin pitch and yaw of various sizes snd shapes of endplates on several sweptback.wimgs.The addition of end“platesto sweptbacktigs increasedthe lfit-curve slope ti the low-lift-coefficientrange. This increase in lift-curve slope tended to increasewith
32、end-plate size and could be pre-dicted from unswept-wing end-platetheory. The end plates also generallydecreasedthe maximum lift coefficient, decreasedthe maximum lift-dragratio, end slightly increasedthe longitudinal stability in the low-lift-meff iciat range.The vsriation of wing effective dihedra
33、lwith lift coefficientwasappreciablyreduced by ticrease in end-plate size. The effectived3hedrsJ.at zero lift could be changed from positive to negative bylowering the end plates. The directional stabilityof the swept wingswas increasedwith increase ti end-plate area mid with rearwsrd move- ,ment of
34、 tie end plates. 1 .Although the end plates increased the j?lap-typeaileron and iler-aileron .”.- a71a15a15a15 a15 a15a15Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN 2229.1.2.394.5.6.7.8.REFERENCES1“”Hemke, Paul E.: Drag of Wings with End P
35、lates NACA Rep. 267, 1927.,17Msngler, W.: The Lift Distribution of Wtigs with End Plates. NACATM 856, 1938.Bates, Willism R.: Collection snd Analysis ofWind-Tunnel Data onthe Characteristicsof IsolatedTail Surfaceswith and withoutEnd Plates. l?ACATN 2291, 1947.Gillis, Clarence L., Polhamus, Edward C
36、., and Gray, JoSe L., Jr.:Charts for Determirdmg Jet-Boundary Corrections for Complete Modelsh 7- by 10-Foot Closed Rectangular Wtid Tunuels. NACA ARR L5G31,1945.pous, Edward C.: Jet-Boundsry-hduced-Upwash Velocities forSweptReflection-PlaneModels Mmted Vertically in 7- by 10-Foot,Closed,Rectangular
37、 Wind Tunnels. NACA TN 1752, 194.8.Herriot, Johu G.: Blockage Corrections for Three-Dtiensional-FlowClosed-ThroatWind Tunnels, with Consideration of the Effect ofCompressibility. NACA RM A7B28, 1947. .Von K I ,“J”- .-.-.- -.-.,- -,; ,.-. . . .,. .: .-” . . . . . . -, -.Provided by IHSNot for ResaleN
38、o reproduction or networking permitted without license from IHS-,-,-se/s= 0.230 $/s.0.236 S#S=O.378-mLz!22.$&;lL2k .5#s.a479 Se/3=C42W Sef!=(2236 se/s =0235 R=aoPc;. .- “: . - -.-.=. - -, - -.- .-, - ., . . -“”7.”- ” . .Provided by IHSNot for ResaleNo reproduction or networking permitted without lic
39、ense from IHS-,-,-I Isfz” +)?igure6.- Geometric characteristics of the 35 sweptback W of aspectratio 3 and taper ratio 0.6Utith two end-plate configwatlcma.s . 3.17 equare feet.fineProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.1,.,:,.,.,1,:.!,“. ,
40、.i!Strut falrlng,.iSting fa7Tunnel center the1.Sting suti. Test wingBlock fw chonghg =6rusttmgfe of attd beorlng.,EY.gure -(.- Schematic dxawing of the free-rolllng sting mounted in the testsection of the Langley 300 MPH i-by lo-foot tumel. “. 1Provided by IHSNot for ResaleNo reproduction or network
41、ing permitted without license from IHS-,-,-, IiAcfi m 2229 27,.RLgure 8.- The 46.70 sweptbackwing of aspect ratio 4 with end platesmounted on sting-balance system in the Langley 300 MPH 7- by 10-foottunnel.,- . . . . . ._. _._. . _ - - .- . - - -Q. . . - - - .,. : .Provided by IHSNot for ResaleNo re
42、production or networking permitted without license from IHS-,-,-.a71I#. - +, .=. .”. . . . . . . .-.- -.“: . . . .: . . . ,.,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-sI1End1/ f$ Li127b50.oCenter of moments0,25chroheplate ./# 1 /a71 1- t:/800” 3600”Figure 9.- Geometixlc characteristics of the h6. swaptback wing of aspectratio 4 and taper ratio 0.60. S = 2.23 Bquare feet.7“ 6.75”1“=w=.IProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
