1、-. -. .- - -.-+” “-. .- - -TECHiTICAL NOTXSf“. NATIONAL ADVISORY COMMIT!T!EZFOR AERONAUTICS-.-=, - .-,._.-.-No. ?55 a71-.WIND-TUNNEL INVESTIGATION OF AN iT,A!2.A.23030 ., .AIRFOIL WITH VARIOUS ARRANGEMENTS OF SLOZ!TED FLAPSBy I. G. RecantLangley Memorial Aeronautical Labor.:.,-. -. . ,-u . .-+= .:.
2、.=” .+ .-. . .: _. .-. . =- .- -=_- -. -.+ “!.+.-. -.;:- c-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2“” N,A.C.A. Technical Note. No. “755 kcombinations for the purpose of improving safety and per- formance. For take-off and initial climb, a w
3、ing-flapcombination capable of producing moderately high lift +with low drag is desirable:. On the other hand, landingrequirements probably make a devic with high lift andvari.blb drag desirable Furthermore, a71such a d.evicoshould give a “small increase in drag when tho flap i rfl-tracted and shoul
4、d give low opokting forces and a nini-mum change in pitching noment with change in flap deflec-tion.Of the various types of flap Invostigatod by theN.A.C.A. , the slottod flaps are apparently most nearlycapable of meeting those specifier.tions; modiun-chord andlarge-chord slottad flape for the N.A.C
5、.A. 23012 and 23021airfoils have bbn devoLoped (referer.ccs 1 to 4) , The.present report gives .the results of tests of tho N.A.C.A,23030 airfoil with slotted flaps of 40-percent and 25.66-percent chord. With the completion of the present. teste,data are therefore avilble for the aerodynamic design,
6、vof slo-owersurface of the . .do/qc) .=-.*Cd.Cm(a. c.)o. .section pitchfng-moment coefficient aboutaerodynamic center of plain airfoil : m(a. c.)o/c2)mwhere .,F=tiin lift, “ ,.:saction profile. “drag.dosection pitching.moment.,. dynamic pressure (pV2/2).W“a.c.)o.-chord of bh?ic airfoil with flap ful
7、ly re-tracted. .cand .,a. angle of attack for infinite aspect ratio?flap. deflection. . .Lam flap chord.i ,.- . . . .-Prcision . ,.#The accuracy. of the various measurements in the testsis believed to be within the following limits: -.*o.1 cd - =0.0006O(cl= “1.0)*()*03- -+o,oo2-+0.003 Cao(cl = ?95)a
8、f - - *o.2+0.0003Flap position - +0.00Icfor the effect of the flam-hine fit-a. -cmax -.-c(a. c.)o -. A correctiontings has been applied to the data for the lap-etractedconditions. This correction amounted to about 5 percentof the minimum drag of the plain airf,oil. No attempt wasmade to determine th
9、e effect of the hinges with the flapsProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-6 N.A.C,A. Technic.al.+LQt No. 755deflectsd. The rolative,merits ofthe vfig-ures 8 and 9 give the contours for the medium-chord flapsl-a and l-b. A number of these c
10、ontours, including somefor high flap deflections, are unclosed %ecause q argeenough area was not covered by the tests. It is believed,however, that the range tested will include any paihchoson for mechanical practicability. In any case, thecontours would close back of tha lip.The wide-chord flap was
11、 deflected fron lCjO to 50 andthe medium-chord flap was deflected from 10o to 60. These ,ranges, although too narrow to establish definitely theultimate maximum lift coefficient of each flaps are thesame as those, investigated for the slotted flaps on theN.A.C.A. 23012 and the N.A,C.A. 23021 airfoil
12、s. The maxi-mum lift coefficients obtained in the tests for the wide-chord flaps l-a and 1+ are 2.82 and 2.90, respectively.These lift coefficients wer obtained with the flaps de-flected 50 and located at a point 2.5 percsnt of the wingchord ahead of and 6 percent below the slot lip. Medium-chord fl
13、ap l-a gives a naximun lift coefficient of 2.59when deflected 60 and located 2.5 percent of the wingchord ahead of and 4 percent below the slot lip. The nax-imun lift coefficient given by medium-chord flap l-b is2.68 when deflected 60 and located 0.5 percent of the wingchord %ehind and 4 percent bel
14、ow the slot lip.The contours of maxinum lift coefficients at flap de-flections of 10 and 200 for all flap arrangenetits are in-cluded to make the data more complete, because the optimumflap positions for these deflections will probably bechosen from considerations of low drag d practic.bilitYof mech
15、anical operation.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-8 N,.A.G.A. Technical Note No. 755Determination of optimum arranements for profileand f%-guree12 and 13 give the contours for the medium-chord flapal-a and l-b. Most “of these contours
16、do not close, but itis belisved that sufficient positions havo been lnvosti-g.ated to cover, any probable flap path.a71 a13a14,.Insufficient data were available to give contours ntCt = 2*O, %ut the position for minimum Cdo at cl = 1.5and 8,f= 20Q is also the position atwhich cd. isminimum at = 2.0 a
17、nd The fairing of this curve is, of.course, arbitrary, but the indications are that a great-ergain in increnent of maximun lift may be expected by in-.“creasing the flap chord fro,m 10 yercent to-25,66 percentthan from 25.66 percent .to 40 percent. This result wouldbe in agreenentwith.the results fo
18、r the slotted flaps of,.different chord on the N;A.C.A. 23012 airfoil (ref.8renceProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10 N.A,.C.A. Tecni.cl Note ,No.,755 J.2). There a_pparently”is no justification for. using the.-wide-chord flap mere-ly b
19、ecause .,it gives a somawhat higherc1 since the hinge moment, being proportional to thema,x3 a71.square of ,the flap chord, would be coneidernbly larger wft;lthis. flap than with tl+emedium-chord flap. %. . ,Effect of scale on incremont of maximum lift coeffi-cient.- The effect of “scale on the Incr
20、ement of maxinunlift coefficient for the medium-chord flap 1-11 is shownin figure 24. The increment of cl Increases withnaxincreasing scale from Re = 1 to about 1.5 nillion. Athigher Reynolds Numbers, no iqcreaso in ACImax occurs.The curve indicates that the increment of nuxinun liftcoefficient may
21、be considered independent of scale in therange of Reynolds Nunb.crs from 1,500,000 to 3,500,mo.Comparison of wide- and medium-chord slotted flapson airfoils of different thickness- Tho results of thepresent tests together with the results ropor%ad in rof-C erencos l,to 4 nake possible an evaluation
22、of the effectof airfoil thickness on.the charncteristlcs of airfoilsequiped with.slotted. flaps. Such an evaluation is madein figure 25, which gives the envelope polars for thewide-chord flap l-b on the N.A.C,A* 23012 (refornco 2),N.A.C.A. 23021 (reference 4)$ and N.A,C.A. 23030 airfoils.As nay be e
23、xpectd, the drag at a .gfven lift coefficientincreases as the thickness of the airfoil increases. Itis of interest to note, however, that the maxinum liftcoefficient at f = 500 and the drag at that lift coef-ficient are about the ecme for the three airfoils.A comparison of medium-chord flap 2-h on t
24、-he N.A.C.A.23012 (reference 1), flap 2-b on the N.A.C.A. 23021 (ref-erence 3) , and.flap l-b on the N.”A,C.A, 23030 airfoils ismade in figure 26. Here again the drag .for .given liftcoefficient increases with wing thickness. Alt!ough themximum lift and the drag nt this lift arc about the smiefor th
25、e 12-percenb and the 21-perccmt-thick airfoils, the.envelope” polar for tho 30-percent-thick airfoil lies in-side the polars for the other airfoils throughout tho lift. .range. The :.-I I I r I I 1III+ - ,=,U.q I1-1 r -1 I I I t I t I I I t II I I 1 1 I I I. I I II i I I I I ! I I 1 Im.-=.,.-. .-.-.
26、1 , , , 1 , , 1 , J9.Z02Z2A 262830Section Iiff coeffiiciemf, C,Figure 14. - Section aercdyuamia ohm-actaristics of X.k.C. L. Z3CW alrfailiith 0.40cslottedflap l-a. -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N.A.C. A. Technical HoteHo. 7S3 .“”Fi
27、k. M”,.,.:r 1 1 1 r 1. 1 x 1 1 I.o-1 I?1 I I I I Iu II I II I I I, , . I , , , ,I VI 71 II I I t 1.=. .”-.,._.-.-=.a-.+.-. .Figure 15. - Section aerodymmio oharmteristios of E. A.C.A. 23030 tif, ccFigure 17. - Section aurcdynamio clmaoteristfca of F. A.C. A. 23030 airfoil with 0.z56 and 2301Z airfoi
28、lm.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-x.;.?. A. Technical Mote Ho. 75!3 Fig. 19.,-.-.,.“. Fiswe 19.- Coqarlmn of 0.2%5c slotted flapo on H.A.C. A. Zl30 airfoil.Provided by IHSNot for ResaleNo reproduction or networking permitted without
29、license from IHS-,-,-,. C*. .Increment of sec+ion maximumI1iIProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N.A.C.A. Teohnioal Hote Ifo. 7M Fl& 22,*.Secfion IJ”*coefficient c,.,.-.Figure 22. - Compmiaon of slotted flaps l-b of diffment ohordm on U.A.C. A. Z50W airfoil.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
