1、cc)-s1,I.,IIi aNATIONALADVISORYCOMMITTEEFOR AERONAUTICSTECHNICAL NOTE 2169WIND-TUNNEL INVESTIGATION AT LOW SPEED OF A 45SWEPTBACK UNTAPERED SENUSPAN WING OF ASPECTRATIO 1.59 EQUIPPED WITH VARIOUS25-PERCENT-CHORD PLAIN FLAPSBy Harold S. Johnsonand JohnR. HagermanLangley Aeronautical Laboratory Langle
2、y Air Force Base, Va.Washington(II. ,. . . . “ /Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TECH LIBY KAFB,NMIumllllllllllllllllnll00L51b7NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSTECHNICAL NOTE a69WIND-TUNNEL INVESTIGATIONAT LOW SPEED OF A h”SW
3、EPTBACK UNTAPERED SEMISPAN WING OF ASPECTRATIO .1.59UIPPED WITH VARIOUS25-PERCENT-CHORDPLAIN FLAPSBy Harold S. Johnson and John R. HagermanSUMMARYA wind-tunnel investigationwas made at low speed to detemine theaerodynamic characteristicsof a hs” sweptback untapered semispan wingof NACA 64.Ao1oairfoi
4、l section normal to the leading edge and aspectratio of 1.59 equipped with 2-percent-chordplain unsealed flaps havingvarious spans and spanwise locations. Ltit, drag, pitching-moment,andflap hinge-moment data were obtained for the wing with the various flaps -deflectedup to 600. A comparison is de w
5、ith data obtained on thepresent wing at 0 of sweep with an aspect ratio of 3.13.In general, changes in angle of attack, flap deflection, flap span,and spanwise location produced trends in lift, drag; pitching moment,and flap hinge moment that were similar to but of different magnitudesfrom those for
6、 unswept wings. Existing empirical and theoretical methodsfor predicting the lift effectiveness of flaps of various spans gave verygood agreement with the experimal results.Because of the increase in the drag coefficients and the associateddecrease in the lift-drag ratio with increasing flap deflect
7、ion, anadvantagemay be gsined by limiting the flaD deflection to moderate angles.(about 00),-even-further increasesmay be desirable,though the lift coefficients increase slightlywithin flap deflection. Flap deflections greater than 30however, when steeper glide-path angles are required.INTRODUCTIONT
8、he Natio Advisoq Committee for Aeronautics is making an extensiveinvestigation of the ltit and control effectiveness of various flaps andcontrol surfaces on wings having plan forms suitable for transonic and supersonicairplanes. The objective is to obtain flap and ailero design-. -.-.- . - . . . -.
9、. - .- - .- - - .- -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 NACA TN 2169criterions similar to those available for unswept winEs of lsrger asectratios (references1 to 6). As-part of this brad st Lift, drag, pitching-mom that is, effective ch
10、ange in angleof attack caused by unit angular change in flap deflectionSubscripts:fi inboard end of flapf. “ outboard end of flapmax maximum .MODEL AND APPARATUSrThe semispan-wingmodel used in the investigationwas constructed,.of laminated mahogany over a solid-steel spar. The plan-form dimensionsar
11、e shown in figure 1. Th wing sections normal to the leading edge wereNACA 64AO1O and the model had an aspect ratio of 1.s9 (based on ful.l-. span dimensions), a taper ratio of 1.0, and 4s0 of sweepback. The wing._. ._ . ._ - _ - . . . . - - _ . -.- .- . .Provided by IHSNot for ResaleNo reproduction
12、or networking permitted without license from IHS-,-,-4 NACA TN 2169,model had neither twist nor dihedral. The model was the sams as thatused in the investigationreported in reference 7, modified m rotating the so-percent-chordline about the root station and rotating the wing-tip chord about its So-p
13、ercent-chordstation so as to be parallel to theair stream.A cross section of the wing showing the details of the 2S-percent-chord unsesled plain flaps is shown in figure 1. The flaps wereconstructed of mahogany with steel spars and had joints at three span-wise stations so that various spans of flap
14、s at,various spanwise locationscould be investigated (fig. 1 and table I). The chordwise gaps betweenflap segments were sealed when two or more flap segments were tested incombination. A motor-driven flap-actuating mechanism which was remotelycontrolledwas used to obtain the various flap deflections
15、 used in thetivestigation, and these deflectionswere cotant cated on ameter by the use of a calibratedpotentiometer which was mounted on thehinge axis near the root chord of the model. The flap hinge momentswere measured by a calibrated electrical resistance type of strain gage.The Lsngl 300 MPH 7-
16、by lo-foot tunnel is a closed-throat single-return tunnel. The semispan-wingmodel was mounted vertically in thetunnel with the root chord adjacent to the ceiling of the tunnel, whichserved as reflected plane (fig. 2). The model was mounted on the six-componentbalance system so that all forces and mo
17、ments acting on-themodel could be measured. A small clearance was tiintained between themcdel and the tunnel ceilhg so that no part of the model came into .contact with the tunnel structure. A -inch-thick metal end plate was16attached to the root of the model to deflect the air flowing into thetest
18、section through the clearancehole in order to minimize the effectof this spanwise air flow on the flow over the model.TESTSAll the tests were performed at an average dypmic pressure ofapproximately 100 pounds per square foot, which corres ends to a Machnumber of 0.27 and a H.eynoldsnumber of about 6
19、.3 x 1J based on the .wing mean aerodynamic chord of 3.s2 feet. Measurements have indicatedthat the tunnel turbulence factor is very close to unity.Tests ofspsn flaps atspan flaps atof 30 for anangle.the wing were made with the inboard half-span and the full-seven deflectionsbetween 0 and 60 and wit
20、h the partial-the outboard and midspan locations at a flap deflectionangle-of-attackrange of from -4 to about the wing stall . .- . . - . - . - - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.5CORRECTIONS,.Jet-bound this comparison shows that thed
21、ecreases in ACL are of the right magnitude. Method I of reference 10was used for the wing equippedwith outboard”flaps and an application ofthe Weissinger thod was used for the wing equippedwith inboard flaps.The value of the flap effectivenessparameter ab used in these esti-mations was 0.% and was o
22、btained from section data of an unsealed flaptype of control on snNACA64AO10 section (reference11), correctedforflap chordby the method of reference 10. In presenting the data theparameter flap area was used instead of fp span since theory assumesthat flaps are cut parallel to free stream. For flaps
23、 cut normal to thehinge sxi.s,the-span of the flap at the hinge axis does not give a truerepresentation of flap size and it appears *t the ratio of flap areato the area of the full-span flap should be used in sll cases. Theagreement of the estimated and theoretical vslues of A% with theexperimental
24、data for a flap deflection of 30 at 0 angle of attack isvery good and indicates that low-aspect-ratioswept wings have variations.of effectiveness-withflap span similar to wings of less sweep snd/orhigher.aspect ratio. *.Drag characteristics.- Analysis of the lift and drag data of fig-ures 3 and 4 in
25、dicates that, for lift coefficients greater than abut 06for the wing with the iriboard-spanflaps deflected and for I-if*coef- 1ficients greater than about 0.8 for the wing with the full-span flapsdeflected, a flap deflection of 30 provides the optdnumvslue of lift-cl?agratio L/D. Further .incrqasesi
26、n flap deflection generally resultm a decrease in the L/D vslues; therefore, because of the increase inthe drag coefficientswith increasing flap deflections, an advantagemsybe gahedly limiting the flap deflectionto moderate angles (about 300),even though the lift coefficients increase slightlywith f
27、urther increasesin flap deflection. Other advantages gained by limiting the flap deflec-tion to moderate sngles sre the lower hinge moments and the smallerlongitudinal-trimchanges resulting from flap deflection, especiallyforthe wing equippedwitl.the fdl-spsn flaps. When high drag coefficientssre de
28、sirable to increase the glide-path angle, flap deflections ofgreater than 300 be used.At the higher lid% coefficients,the drag coefficients generallydecreasedas the flap span was increased (figs. 3 to ). The drag coef-Ificients also decreased as the”hslf-srmnflas were moved to a more inboardlocation
29、 (fig. 6). These effects of “le o attack, flap deflection,flap span, and spsnwiseflap location weretidel at 0 of sweep (reference7).flapPitching-moment characteristics.-Fordeflections, the vdng had an unstable,.generally-the same as for thedll flap configurationsandvariation of pitching-moment.Provi
30、ded by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.NACA TN 2169 7coefficientwith ltit coefficient at low values of , the aerodynamiccenter being located at about 0.18?(figs.3 to 6). This longitudinalinstability decreased and the vsriation of with became sta
31、bleas the lift coefficientwas increased.Flap deflection produced negative increments of pitching-momentcoefficient ACm that were linear with flap deflectionfor deflecti6hsof less than about20 (fig. 8). Flap deflections greater than 20generally gave progressively smaller increases in ACm with,increas
32、ingflap deflection (figs. 3, b, d 8). Similar effects due to flap deflec-tion were noted for the unswept wing (reference7), although for theunswept configuration the ticrements were less sffectedby angle-of-attack variations than those for the swept configuration.The variations-of the pitching-momen
33、t coefficient“withflap spanand spanwise location (fig. 10) were similar to those for sweptbackwingsof higher aspect ratios. The method of reference 10 did not satisfactorilypredict the magnitudes of these variations for the low-aspect-ratiowingof the present investigation.Hinge-moment characteristic
34、s.The flap hinge-moment data of fig-ures 3 to 6 show, as would normally be expected, that the values of flaphinge-momarb coefficient generslly became more negative as either theflap,deflection or the angle of attack was increased except for thehigher flap deflectionswhere the values of became less n
35、egativewith increasing angle of attack. (See-figs.3 and b.) Although theeffects of flap span were slight and, in some cases, inconsistent, theMge-moment coefficients of the outboard flaps generally became lessnegative as the flap span was increased (fig. ). A similsr decreasein magnitude of Ch due t
36、o spanwise location of the half-spsn flapswas noted when the flap was moved tiboard from the wing tip (fig. 6)These effects of flap deflection,flap span, and spanwise locationon the hinge-moment characteristics are similar to those for the modelat 0 of sweep (reference7), thou,generally of smaller m
37、agnitude.CONCLUSIONSA wind-tunnel investigation was made at low speed to determine theaerodynamic characteristic=of a bs” sweptbackuntpered semispan wingof aspect ratio 1.s9 equipped with 2S-percent-chordunsesled plain flaps. . . .-. - - . - - -.-.- _ ._Provided by IHSNot for ResaleNo reproduction o
38、r networking permitted without license from IHS-,-,-8 NACATN 2169having vsrious spans and spanwise locations. The results of the investi- gation led to the following conclusions:1. Changes in angle of attack, flap deflection,flap span, andspanwiseflap location generally produced trends in lift, drag
39、, pitchingmoment, and flap hinge moment that were similar to but of differentmagnitude from those for uuswept wings.2. lkisting empiricsl and theoretical methods for predicting thet effectivenessof flaps of vsrious spans gave very good agreementwith the experimentalresults. #3. Because of the increa
40、se in the drag coefficients and the associ-. ated decrease in the values of the lift-drag ratio with increasing flapdeflection, an advantagemay be gained by limiting the flap deflectionto moderate angles (about300), even though slight increases in liftcoefficientresult from further increases in flap
41、 deflection. Flapdeflections greater than 30 may be desirable,however, when steepergde-path angles sre required.Langley Aeronautical LaboratoNational Adviso Committee for AeronauticsLangley Air Force Base, Vs., -12, 190.,.- . - - . .Provided by IHSNot for ResaleNo reproduction or networking permitte
42、d without license from IHS-,-,-NACATN 2169REFERENCES9.1. House, R. O.: The Effects of Partial-Span Plain Flaps on the Aero-dynamic Characteristicsof a Rectangular and a Tapered Clark Y Wing. “NACATN 663, 1938.2. House, Rufus O.: The Effects of Partial-Span Slotted Flaps on theAerynsmic Characteristi
43、cs of a Rectangular and a Tapered N.A.C.A.23012 wing. NACATN 719, 1939.3. Wenzinger, Carl J.: The Effects of Full-Span and Partial-Span SplitFlaps on the Aerodynamic Characteristics of a Tapered Wing. NACATN 505, 1934a714. Weick, Fred E., md Jones, Robert T.: RYfo = 0.557;. . . . . . . - - . Provide
44、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.16foCF-5-6“.-NACA TN 2169,.:2 0 2 4 .6 .8 l 6? /4M7 CYfo = 0.95$.- . - .- - - - .-. . . - _ .-. -. ._ _ _Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-18.-2
45、k. I I I Iv-w-i-etiiiiiii T”P=:9Figure 4 Concluded.-._ _ -. - - _ -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA TN 2169 19FLo 0 flail) M41gA 0.160 0.7957n o cc 72824I I I /1 r .4 I/f, ,! I!M#+0-4.7.6.5QQ./oFigure 5.- Effect of the flap span o
46、n the aerodynamic characteristics inpitch of the 45 sweptbackwing having au aspect ratio of 1.59 smd( )equipped with outboard flaps yfo = 0.95 . bf = 30.+ . - . . . . .-. .- -. _ . -. -. . . . . . . _Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-20
47、nNACA TN 2169“e”.Figure 5.- Concluded.,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA TN 2169 . 21?Qo .2 # .6 .8 LO /2 /4Lrft coeficien$ Figure 6.- Effect of spsnwise flap location on the aerodynamiccharacteristicsin pitch of the 45 swe%ack wing having anaspect ratio of 1.59 and equipped with approximatelyhalf-spnflaps. bf = 300.- .-. . . - . . . - . - .-. . . . .- . . . . . . .- -Provided by IHSNot for ResaleNo reproduction or networking permitted
