REPORT No. 472 WIND-TUNNEL TESTS ON COMBINATIONS OF A WING WITH FIXED AUXILIARY AIRFOILS HAVING VARIOUS CHORDS AND PROFILES BY FRIIDE.W~ICK andROBERT Smrmis . suMMARY Various auxiliary aixfoi.le having three. d&mnt airfoil sections and wtMrd di$ered chard lengths were teded in combination &h a G?ark Y model wing in a Sujicient number of relai%e poeitti to Cletemn?h -th# optimum wiih regard to certain criterions of aerodynamic performance. 2%4 airfoil sectiom inclwded a ~- metricu.1projile, ma of medium camber, and a highly cambered one. The chard ti of the auxil~ airfoils ranged from 7.6 to % pemeid of the chord of the main wing, and tlw span was equu.1to tlwt of thamain wing. % tats were made in the NA.C.A. 6#oot vertical wind tunnel. Ii was found thai each of the auxiliary airfoil com- binuliorw tested, regardless of eize or airfoil section, ku.d, W?M?J fOCil&Xi? ti it.8 btl?t pO&iiiO?L, &UbStWlt~y higher oa.hux of th maximum lift cwjicid and of the ratio 6!Lntaz2/~Dmin hn th ?n& k~ h. % &mum tdwee of tlw lift coejicz%dobtained, based on the tots..? area, were uety nearly th same &h all the awihry airfoils tedqi. The symmetrical airfoilk gave lower dues of the minimum drag coq%%at and higher values of the rdti CL..%@D.i. ttin th8 ~mbe?%d ad~ airfoils. The highest d~ of the raiio CL-=/CDnim was obtained &h tha ~mdrical auxiliury having a chord .Lmgth14.6 per& of the main wing chord. The positim giving the highest values of this ratw did not vary greatly for the di$erent auzi.1~ airfoils tested, wept for the nurrowest M, which gave higher va-bu..a in tOwerpoeitiun$. A.ddithna.l tats, in which the au.xi?iury ai.q%iikwere supported separaMy, were made to detemnine the dimkion of air load between t~ auxiliary and the main wing for two representaiwe cmwa. l%e remdts showed i%d the auxiliary a&foil took a relatively large proportiim of the total load, particukzrly in the case of the highly cam- beredauxiliary at low angles of attack. INTRODU~ON Ina previous investigation (reference 1) it ma found that with an auxiliary airfoil tied in a certain position ahead of the main wing the combination had a sub- stantially higher value of the maximti lift coefficient (based on total area) and of the speed-range criterion, cL_/cAta, th~ tithm of the &’foik don& Th@8 earlier testi were made with Q single form of auxilimy airfoil now referred to as the N.A.C.A. 22. The chord was 14.6 percent of the main -wing chord, and the profle was highly cambered and of medium thickness. This qudiwy airfoil was tested in a large number of positions near the front of the main wing in order to find the bmt looation. The tests described in the present report continue the investigation of fixed auxiliary airfoils to include the effect of variations in size and in airfoil section. Four sizes were tested having the original NJLC.A. 22 section, four hming a symmetrical section (N.A.C.A. 0012), and one having the Clark Y section. The lift md drag of the combinations were measured with each of the auxiliary airfoils in a sufficient number of positions ahead of the main wing to determine the optimum location. Pitching moments were then measured with each auxiliary airfoil in one or two of the beat positions. Finally, the air force on the auxilky airfoil was found for two representative combinations. APPARATUS AND METHODS Wind tunneL-The tests were made in the 5-foot vertical wind tynnel under essentisly the same con- ditions as those of the original portion of the”i.&esti-- gation (reference 1). The wind tunnel is described in detail in reference 2. A “reflection plane” and half-span model were used to permit as high a Rey- nolds Number as possible. Models,-The main wing was a rectangukw Clark Y airfoil, eomticted of mahogany, with a lo-inch chord. and a 30-inoh semispam The auxiliary air- foils, whose seroispans were also 30 inches, were con- structed of ahnninurn alloy. The chords of the auxil- iary airfoils were varied until the tests indicated that the optimum range had been covered. The original &4Y cabwd section (N.A.C.A. 22) was tested with ohords of 7.5, 11, 14.5 (check on original in optimum position only), and 25 percent of the main 567 https://ntrs.nasa.gov/search.jsp?R=19930091546 2018-05-07T08:12:36+00:00Z
Transcript
REPORT No. 472
WIND-TUNNEL TESTS ON COMBINATIONS OF A WING WITH FIXED AUXILIARYAIRFOILS HAVING VARIOUS CHORDS AND PROFILES
BY FRIIDE. W~ICK and ROBERT Smrmis
. suMMARY
Various auxiliary aixfoi.le having three.d&mntairfoil sections and wtMrd di$ered chard lengths wereteded in combination &h a G?ark Y model wing in aSujicient number of relai%e poeitti to Cletemn?h -th#optimum wiih regard to certain criterions of aerodynamicperformance. 2%4 airfoil sectiom inclwded a ~-metricu.1projile, ma of medium camber, and a highlycambered one. The chard ti of the auxil~ airfoilsranged from 7.6 to % pemeid of the chord of the mainwing, and tlw span was equu.1to tlwt of tha main wing.% tats were made in the NA.C.A. 6#oot verticalwind tunnel.
Ii was found thai each of the auxiliary airfoil com-binuliorw tested, regardless of eize or airfoil section, ku.d,W?M?JfOCil&Xi?ti it.8 btl?t pO&iiiO?L,&UbStWlt~y higheroa.hux of th maximum lift cwjicid and of the ratio6!Lntaz2/~Dmin hn th ?n& k~ h. % &mum
tdwee of tlw lift coejicz%dobtained, based on the tots..?area, were uety nearly th same &h all the awihryairfoils tedqi. The symmetrical airfoilk gave lowerdues of the minimum drag coq%%at and higher valuesof the rdti CL..%@D.i. ttin th8 ~mbe?%d ad~airfoils. The highest d~ of the raiio CL-=/CDnimwas obtained &h tha ~mdrical auxiliury having achord .Lmgth14.6 per& of the main wing chord. Thepositim giving the highest values of this ratw did notvary greatly for the di$erent auzi.1~ airfoils tested,wept for the nurrowest M, which gave higher va-bu..ain tOwerpoeitiun$.
A.ddithna.l tats, in which the au.xi?iury ai.q%iikweresupported separaMy, were made to detemnine the dimkionof air load between t~ auxiliary and the main wing fortwo representaiwe cmwa. l%e remdts showed i%d theauxiliary a&foil took a relatively large proportiim ofthe total load, particukzrly in the case of the highly cam-beredauxiliary at low angles of attack.
INTRODU~ON
In a previous investigation (reference 1) it ma foundthat with an auxiliary airfoil tied in a certain positionahead of the main wing the combination had a sub-
stantially higher value of the maximti lift coefficient(based on total area) and of the speed-range criterion,cL_/cAta, th~ tithm of the &’foik don& Th@8earlier testi were made with Qsingle form of auxilimyairfoil now referred to as the N.A.C.A. 22. The chordwas 14.6 percent of the main -wing chord, and theprofle was highly cambered and of medium thickness.This qudiwy airfoil was tested in a large number ofpositions near the front of the main wing in order tofind the bmt looation.
The tests described in the present report continuethe investigation of fixed auxiliary airfoils to includethe effect of variations in size and in airfoil section.Four sizes were tested having the original NJLC.A.22 section, four hming a symmetrical section (N.A.C.A.0012), and one having the Clark Y section. The liftmd drag of the combinations were measured witheach of the auxiliary airfoils in a sufficient number ofpositions ahead of the main wing to determine theoptimum location. Pitching moments were thenmeasured with each auxiliary airfoil in one or two ofthe beat positions. Finally, the air force on theauxilky airfoil was found for two representativecombinations.
APPARATUS AND METHODS
Wind tunneL-The tests were made in the 5-footvertical wind tynnel under essentisly the same con-ditions as those of the original portion of the”i.&esti--gation (reference 1). The wind tunnel is describedin detail in reference 2. A “reflection plane” andhalf-span model were used to permit as high a Rey-nolds Number as possible.
Models,-The main wing was a rectangukw ClarkY airfoil, eomticted of mahogany, with a lo-inchchord. and a 30-inoh semispam The auxiliary air-foils, whose seroispans were also 30 inches, were con-structed of ahnninurn alloy. The chords of the auxil-iary airfoils were varied until the tests indicated thatthe optimum range had been covered. The original&4Y cabwd section(N.A.C.A. 22) was testedwith ohords of 7.5, 11, 14.5 (check on original inoptimum position only), and 25 percent of the main
568 REPORT NATIONAL ADVISORY COMMKCI!EE FOR ADRONAIJTICS
wing chord. The symmetrical section, which wasthe next tested, was the N.A.C.A. 0012. This sectionwas tested with chords of 7.5, 11,14.5,and 18 percentof the main ‘iv@ chord, the 25 percent size hw@been indicated as definitely too large by the tests withthe original N.A.C.A. 22 section. The Clark Y sec-tion was tested with the 14.5 percent chord only.
independently of the main wing. The air force onthe main wing was measured in the presence of theauxiliary and subtracted from the total force to givethe force on the auxiliary alone.
Tests.-The lift and drag over a range of rqjlea ofattack were measured with each of the auxiliary nir-foils in a sufficient number of positions with respect
Mdn wing with 14.6pmmnt symmetricalaoxihry airfoil
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ORDINATES OF AUXILIARIES
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FIOUEE I.-&Mom of8oxuhrg drfoiu taed.
All three sections have approximately the same thick- to the main wing to determine the optimum loc~tionness and form except fo;- the camber, which variesthrough a large range. The cross-sectional views ofthe various auxilhuy airfoils are shown together witha table of ordinates in figure 1. The auxiliary air-foila were supported at each end and at two interme-diate petitions by metal fittings, as shown i.nfigure 2.’
For obtain@ the force on the auxiliary airfoilseparately, fixtures were made to support the auxiliary
according to the criterion C&u2/OD~im~which wasused in reference 1. The variations in position weremade in the following manner. The angle 8 betweenthe chord line of the auxiliary and that of the mainwing was changed about an axis through the trailingedge of the auxiliary until the angle giving the high-est value of the ratio cLmu2/c~fe was determined.This procedure was repeated for various trailing-edge
WIND+?UNNEL TESTS ON COMBINATIONS OF
locations until closed contour charts of the maximumvalue of the ratio CL_=/CD.~a obtained at each trailing-edge location could be drawn, showing that the positiongiving the highest value had been determined.
The 14.5 percent N.A.C.A. 22 auxiliary airfoil,which was the one tested in various positiom inreference 1, was retested only at the best position, asa check. The results are slightly difl?erentfrom thoseof the previous tests, which is partly due to a changeof the fittings supporting the auxiliary airfoil andpartly to the normal experimental error. The newfittings, designed to increase the rigtidityof the sebup,crmsed an interference effect resulting in a reductionof the maximum lift coefficient of about 3 percent(reference 3).
The pitching moments, which were obtained witha slight change in the balance arrangement, weremetisured for the best positions of each auxiliaryairfoil.
The tests to determine the distribution of loadbetween the mxilimy airfoil and the main wing weremade with two representative auxiliary airfoils. Onehad the highly cambered N.A.C.A. 22 section and theother the symmetrical N.A.C.A. 0012 section, bothbeing 14.6 percent of the main wing chord. Each ofthe rmxiliary airfoils was tested at two dilhrent set-tings of the angle 6. The values of the air loads onthe auxiliary airfoils must be considered as approxi-mate, for they were obtained as the diilerence betweentwo relatively large forces and the accuracy wastherefore not high.
RESULTS AND DISCUSSION
The results of the simple lift and drag tests aregiven in tables I to IX in terms of several criticalvalues, or criterions, of the aerodynamic character-istics. The lift and ‘drag coefficients are based onthe area of the main wing plus that of the auxiliary,and for this reason the various combinations must becompared as complete units.
CONTOUFL9OF PERFORMANCE Criterions
The variations of four of the criterions with changesin the locations of the various auxiliary airfoils areshown by means of contour charts which serve asconvenient aids to the selection of the optimum loca-tions (figs. 3 to 10). The values on the contour chartsare those obtained with the auxiliary airfoil set at theangles giving the highest value of CL=z/Cmi. for eachtrailing-edge location; where two angles gave the samevalue within the experimental error, the choice wasbased on the other criterions. The values for the dif-ferent angles are given in tables I to IX. The four setsof contoum shown on each of the figures are for thefollowing criterions:
n. O“~U=/UD~iS,which is the main criterion inselecting the optimum position. This is an &bitrary
4076-637
A~GWITE_DA~ Y AIRFom3 569
criterion which gives equal weight to the maximum liftcoefficient and the speed-range ratio CL~~/CD~ti.
b. CL=.c. L/D at CL= 0.7, which is used as a criterion of the
effectiveness in climbing tlight.d. L/D at CL-, which gives an indication of the
steepest gliding angle obtainable in unstalled flight.An examination of the contour charts shows that nosingle auxiliary airfoil had the best characteristics onthe basis of all the criterions. The variation of thecharacteristics with size, profile, and location of the
‘f7efleakw plane
2-0
-1.
Detail of intermed,bfesupport
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T!6=s’-one/ 1Eridplafe No.2
PI13UmZ—Methodofsupporting8X alrfdk.
auxiliary is complex and require that the data bestudied in detail in order to select the best auxiliaryairfoil to fuliill the requirements of any particular set ofoperating conditions.
Elleot of location.-In general, the location giving thehighest value of the ratio C&’/CDm,n for any of themxilimy airfoils was not greatly different from thatgiving the highwt value of oLmOzjbeing in most casesdightly lower and farther forward. The positions givingLhehighest vfdues of CLmm2/C~,Zdid not vary greatlywith airfoil section or with size of auxiliary, except forthe smallest size, which required a lower position for,both the airfoil sections tested. In fac~ for each size
.—.. ... —------ ---- ..-- .=----- - -. .-
570 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
5L
LOCIoftdlfw-edm dtfm for eqrmfPAWS ofbL.#/cD.im obtefned wftb a 7.Spem?ntcNA.CA. 22amfUaWeMdl w attbeoptimum engle fer eachpdtfon.
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k.-. I ! 1- 1~ 30 25 20 5 L.E.
Percwt chord
LQ30f Weflfnxd&!e IXUftiOCM fer equef vefnesof LID at&-O.7abtaimM wftb a 7.5IMa?nt cNA.CA. Z2atdWrMrfofl A at theo@rmrrw@ford fxdtfen
.
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Iaof of Mlfng+dge PMUIOnefor WJUOIvfdcrE9Of CL.. obtofnod dti n 7.6Per-rnntcN.A.OA. 22ardffary efrfell f$t at tbe opthnrmmrigle for mob pdtlon.
~GUEE &
M of tmffbx+&a IYIWMM for equef velnrs of L/D at G-- obti~ ~Ilh a 7+~tcNA.C.A. 22anxifkrYdrfoIlaot at theoptinmrnengle formnb@tIon.
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15 10 5 L.EPercent chord
b. .
Percent chord
LCICIOf_#Kc@tkIM fOrMItiValU=OfcL-d/C%A0bt8fn&iT VfthOI.llLOwc?nt cN-A.C.A. 22amflferYafrfollE& at theoptfmrnn engkfmachpmftfon.
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I 1 I 1 130 25 20 15 5
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Ldoftreflhuwdmmtfene forewrdmftmof L/Dat C~-O.7obtafndwItban 11.0wrcmt cN-A.OA ~anxflkyefrfeflcet at theoptbnurnenglefer~ LWMOU
M d tmflfngdge pdtfons for qrml vahm of CL.. obtafnod with an 11.0pacent c NA.OA. arufliem afrfofl aet at the qrtfmnm engle for mcb mcftforr.
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Lad of trrdlfng+dgo pmitlemforeqnol vrducaofL/Dat cL.. Obtahed Ivkbsn ILO
~tcN.A.O.A. ~arIxWIY’efrfofkot at theoptfrmmrongfeforeaoh pnftlon.
FmrRE 4.
WIND~L TESTS ON COMSINAITONS OF AWllfGWIITI~A uxfLIARY AIRFom 571
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Locfoftroflfnwfgapr61tforM[orwmf vahs ofcL.uVcD.i. ObkfrM Wftba Locf of tmflbrg+lga pmftforre for eqrml vakm of CL.. obtafnad wftb a Z&O‘2S,0percent c N.A.O.A. 22auxilfary elrfoU eat at tbe optfmmrr angle for each ~t c N.A.O-A. 22 aurflfary afrfoil set at the optfmmrr angle for eachMsltfon. Wtforl.
~~~& 25 20 15 10 5 L.E.
Percenf chord
7.001Of trafllng+dge @tfom for WIef valnrs ofL/D atCL-0.7obti~ TT~ a LedoftreflhgdgeposftfmKIforequalVafrr=of L/D at CL-. obtalnerf wftb u25,0percent c N. A.C.A. 22arrxfllaryafrfoU set at tie optfmn.m ~gle for eac.b ZhOrmcmrt c N.A.C.A. !22anxfky efrfofl W at tbc optmmm angle for eacJpmltlon. Pr8ftfon.
FIQCEEs.
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M of trefllng+rfgo IXMMonafor ewal vafuca Of CL-A/CD.I. ob~~ wftb a7.5permntcN.A.C.A.WlflaruUfaryefrfoffwtat tbeoRtfmnrrrM@foraatiLwOftfoa.
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5L f2/M of tmflfnE+edgepasItfmMfor emmf tin= of L/D at CL-O.7 Obtti@ wf~
a 7.6Wcent e NA.C.A. mlZ anxflfary afrfoll sot at Ureoptfmnrn angle for eachmluon.
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M ef traflhrg~ge IYMMone for H@ velaea of CL.. obtafnerl wftb [a 7Awcmt c N.A.O.A. MIZ a~ tim mt at tie oPtfmm m~e for mm&tfoL
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led d bafffng+rlge WUMOm for equal VOIW of L/D at CL.. obta.fn~ witha 7J permnt c Nd.O.A. IM12aurfliam afrfoff setat tbe optfmum angle fer eachpmftfon .. .
572 REPORT NATIONAL ADVLSORY COMMTFT.EIl FOR AERONAUTICS
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W of traflhg-xlge pxftfoneforequal vdnes ofCL..1/CD.r. obtained with anlLO p?montc N.ACA IXIf2acrxfhcy akfeffeetat the optfnmm angle for embfx6ftfo.
L@f of traIUng+ffge pmkfons for equal VW of L/D at CL-O.7 obtafmi withan lLO p.?rc?ntc N. A. C-A IY)12amflfary afrfoff set at the optfmnrn angfe for& lXSitbL
M of _+.ige @tfOI18 for WMLI VtlfCIM of Ccmo obtabmi with an 11.0w?.mantc NA.O.A IX112anxflky alrfoll sotatthe optimum angle for mobpmltfon.
~~i630 25 20 15 IO 5 1.E.
Percent chord
Lod of traflfng+ifge pcaitfoIM for eqcmlvafnes of L/D at CL.. obtafnod wltb anlLO -t c N.A.C.A. fO12arrxilky afrfoil cot at tba optfmum angle for eaofrWtien.
Froum 7’.
J-mlofhilfng+ fxuftfoJMfor ewml vafofsof CL.4CD.t, obtained wfth a 14.5pment c N. A.OA. w12 armIfkY afrfolf set at tbe optbmnn angle for eachpmitfon.
g~~Q 15 10 5 LE.
Percent chord
W of fraMng&ge pxftfom for eqnal valnea of L/D at CL-O.7 obtafned witha 14.5Prcent c N.A.C.A. IIW2amfEars ahfoIf W at the optfrnmn angle forJ91cJl&tfcal.
~~~50 25 20 /5 10 5 L.E.
Percent chord
Luef of tmfling+ifga IX&tfona for qyal valnes of CL.” obtained with a 14J3mmmt c N.A.C-A IYJ~ a- afrfofl set at the optfmum angle for enahlmftfou
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tad of traflfng+dga pAtfonn for equal vain@ of L/D at CL.. obthed wltb a14.6~t c N.A.O.& m12 auxULaryafrfofl cat at the opttnmm 00g1efor eachfmftlen.
FIGUXB8.
COMBINATIONS OF AWINGWITEIWXEDAIXULIAR Y AEfFOILS 573
~~~gio 25 20 15 JO 5 L.E
Percent chord
W of traflfng+clge @tIona for@ valu~ of CL. ACD.~ obtained with an18.0pment c N. A.O.A W12auxllfary afrfoll W at the optfmum angle for eachPo9ftton.
~~~~30 25 20 15 10 5 L.E.
Percent chord
M of traflfng-edge WitIons for @ valn~ of CL.. obtafned wftb rm lE.Ow’cant c N.A.C.A.f012anxffkuy airfoff W at the optfmom angle for [email protected].
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~30 25 20 15 10 51 I 1 1 I
L.E. ~.m 25 20 15 5Percent chord
L.E.Percenf cho%
1A of trafffng+ilge fxaftfona for eqnal vakccaof L/D at CL4L7 obtafn~ withan 1S.0pemantc N. A.O.A. W2 anxflky airfoff @ at theoptfrmunangle for eachfmsltfon.
Id of trafffngdge fmcitbm for ewal vahm of L/D at CL-U obtafnecfwftb anl&O ~t c N.A.C.A. mt2 anxflhry afrfofl cet at theoptfnmmangfefor 6arhpmfuem
~$~t-25 20 15 10 5 L.E.
Percent chord
M of trofffng+dgormftfons fer cqnal valum of CL.4WD.[. Obkfmf wkb a 14.6Hcont c Cfark Y auxfffmy afrfoll aet at the optfmmn angle for each @tfon.
25 r
-0I I 1 1 I
~~ 25 20 5 ‘ L.E.PercerYcho2
W oftraflfnwlgomftIona fer eqnaf valuw of L/D at CL-0.7 obhfmf wftba 14.6w-t cClarkYanxfffary alrfoff aet at the optfmuxnangle fer mcb pmf-tfon,
~I 1 I I I
25 20 15 10 5 L.E.Percent chord
bd of traffkw-edge @tIons fcr equal valm of CL.. obtafmd wftb a 1~ W-cont c Clark Y anxflfary afrfoff wt at the optfmnm angfefor 4 rmftfou
uPercent chord
Lid of traflfngdge pdtform for equal valu= of LID at C~.” obtafned witha 14.5-t c Clark Y aurifkuy afrfofl set at the optbnnm angle fer each pmf-tfon.
FmuEE10.
574 REPORT NATIONAL ADVISORY COMMTITEE FOR AERONAUTICS
of auxiliary airfoil except the extreme 7.5 and 25 per-cent sizes, and for each of the three airfoil sections, aposition with the trod@ edge 14percent ahead of thenose and 12 percent above the chord line of the main**gave a value of CLmaIwithin 2 percent and a valueof the ratio OL.=i/ODni. within 6 percent of the masi-mum value obtained for the particular auxikry airfoilat any position. The bwt angle 6 was within 3° ofzero for all medium-sized auxiliary airfoils, regardlessof section.
In most case9, moving the auxiliary airfoil closer tothe main wing than the position giving the l@hestvalue of the ratio Cm=z/Chti gave a s&mhtincrease inthe value of L/Din the climbing range and at the sametime a decrease in the value of L/D near maximum lift,both of which result in an increase in the range ofpossible gliding angles. Considering this fact, togetherwith the similar condition in regard to the mtiumlift coefficient, and also the structural requirements,the optimum position would seem to be somewhatcloser to the main wing than the position giving thehighest ratio of &uas2/C.m~n.No rigid general dO canbe drawn, however, for the details oj ea~h case must re-considered separately.
Effect of size.-A comparison of the results for tlieditTerentsized rmxiliaryairfoils as given on the contourcharts shows that for any one airfoil section there wasno gr~t change in the values of the criterions withchange in size within the range covered, if the valuestaken are for each size in its best position. The maxi-mum lift coticients obtained with the auxilky airfoilsof rdlsizes and sections, set at the value of ~which gavethe highest VfdUOof the ratio CZmU2/Ctiin,were allwithin 2 percent (or approximately within the experi-mental error) of the value 1.64, except for the valuewith the 25 percent auxiliary airfoil, which was within4 percent. With the highly cambered N.A.C.A. 22section the smaller auxiliary airfoils had slightly highervalues of the ratio CZ_2/CDmiSthan the huger ones, butthe entire raqge was only 7 percent. With the sym-metrical section the variation of the maximum value ofthe ratio CLmaxf/CDmimwith sizewas about twice asgreat,the highest value being obtained with the medium sizeand the lowest values with the extreme sizes.
The values of the climb criterion, L/D at C.= 0.7,were nearly the same for all sizes, but were &uhtlygreater for the smallest size than for the others. Thesmallest sized mmi.liary airfoils, unfortunately, alsogave definitely higher values of the criterion of steepglides, L/D at 0..-, than the others. The variationamong the larger sizes was very small.
IHect of auxilkwy airfoil section.-Although theauxiliary airfoils of all sizes and sections gave approxi-mately the same values of the maximum lift coefficient,the *U d.r%”coefficients were found to be decid-edly lower with the auxiliary airfoils of symmetrical sec-tion than with the cambered onw, so that l@her values
of the ratio CLmg/CD.la were obt@ed with them.The cross plots for the three diiferent sections with the14.5 percent chord indicated that the highest values ofthe ratio obtained with ench varied consistently withthe camber, the value with the symmetrical N,A.C,A,00]2 a@iliary airfoil being 199, that for the Clark Ybeing 166, and that for the highly cambered N.A.C,A,22,being 154. The value of 199 obtained with the14.5 percent symmetrical auxiliary airfoil was the high-est found in the investigation.
The values of LJD at CL= 0.7 were approximately thesame for the symmetrical and for the highly camberedsections, but the valuea of LID at (?Z.U were slightlylower with the highly cambered sections.
LIFT,DRAG, AND CRNTER.OF.PRESSURE CURVES FOR OPTIMUMPOSITIONS
Curves of lift, drag, and cmter-of-pressure coefE-cients against angle of attack are given in figures 11 to19 for each of the auxiliary airfoils in one or more ofthe optimum positions, selected mainly on th~ basis ofthe ratio 0zmu3/CDmin. In addition, values of thepitching-moment coefficients for all the angles of attackmeasured are given in table X. The valuea of center-of-pressure positions were computed on the basis ofthe main wing chord and the values of 0. on the basisof the main wing chord and the combined arem,
The numerical value of C= at zero lift for the combi-nation with the 14.5 percent Clark Y auxiliary airfoilwas found to be 14 percent less than the value for theplain Clark Y wing alone. With the symmetricalauxiliary airfoil having the 11 percent chord the valuewas the same as for the plain wing, but it becamegreater if tie size of the auxiliary was either increasedor decreased from the 11 percent point. The highlycambered N.A.C.A. 22 auxilia~ airfoilsgave somewhatsmaller negative valuea than the plain Clark Y wing,the values decreasing as the size of the auxiliary wasincreased. If C. is plotted against 0~ the curve willnot in any case be a straight line, but will have a defi-nite bend in the neighborhood of the 5° angle of attack,
DIVISION OF ME LOADBFPWEENMAINWINGANDAUXILIARYAIRFOIL
The results of the tests to show the division of theair load between the main wing and the two selectedauxiliary airfoils are shown in i@re 20. The load onthe auxiliaries is divided into normal and chord com-ponents and these are given in terms of the total lifton the main wing plus the auxiliary. The auxiliaryairfoil hav@ the symmetrical section sustained inthe neighborhood of one fifth of the total load through-out the entire angle+f-attack range tested. Thehi@ly cambered N.A.CA. 22 ausiliary airfoil sus-tained about the same portion of the total load at theI@h lift coefficients, but a higher proportion if theangle of attack was reduced. At a= 0° the lowestangle of attack which could be obtained with the set-up
WUTDWUNNEL TESTS ON COMBINATIONS OF A ~G WITH .FIXED AUXTLIARY AmFolls 575
d, degrees
/.6
I.z
CL
.6
‘%
.4
c
-.4
(A) Anx. T.E. 16.0-t ahmd of L. E., 4_5percentakuweohord, J=5”.(B) Arm. l’.E. 19.!3Permnt dread OfL.E., 2.5~cent above cherd, 6=2J@.(C) Am. T.E. 11.1percentaheadof L, E., 7.4percantabme cherd, d=lW.
~OUUE 11.-Ohnr@mMf u wfth N.A.C.A. 22,7.6-t cherd tilary.
Io Arr 0/7 ged enf (Al
L.15 ~
20:>0
/ T C.P.40 j
f
, L60:
JL6 P ~-;
) {00 GCL /
f.2
c= / .\ . >
.8
c’ /- - ‘
,4
) ‘
F.4
0 /
~ c=o w ‘
-.4-8 0 8 16 24 32 40
d, degrees
(A) Am. T.E. 15.2~t ahead of L. E., lZO percent above ofmrd, 8=0”.
FIOIJEE13.-OhamcteriwIrs with N.A.O& 22j14.5pwmnt chord aoxfhry.
(A) Aux. T.E. 11J5~t ahead of L.E., 14.0~t abeve chord, 3=0”.(B) Am T.E. 10.0~t aheadof L.EV 4.5~t ahOVeeherd, d-2~.
WIND-TUNNEL TESTS ON COMBINAmONS OF A -G ~ ~ AuxnJARY AIRForLs 577
used, approximately half the total load was taken bythe N.A.C.A. 22 auxiliary airfoil.
CONCLUSIONS
1.Each of the ausiliary airfoil combinations tested,regardless of size or airfoil section, gave, in the bestpositions, substantially higher values of (?Lmas and ofthe ratio CL.n2/UD.j.than the main wing alone.
2. The maximum values of C’ obtained, based onthe total area, were very nearly the same with all themmiliaxy airfoils teated.
3. The symmetrical auxiliary airfoils gave lowervaluw of the minimum drag coefficient and highervalues of the ratio &U2/CDmiCthan the auxiliary air-foils having other sections, the l@hest value of theratioCLmU2/CDmi* being obtained with the 14.6 per-cent symmetrical auxiliary airfoil.
4. The positions giving @e highest values of theratio Ckm2/Omi.did not vaxy greatly for the auxil-iary airfoils of di.ilerentsizesand sections tested, exceptfor the smallest size, which required a lower position.
6. In most cases within the range of the tests, mov-ing the auxiliary airfoil closer to the main wing thanthe position giving the high-t value of the ratioOfiwZ/Um,. gave Qslight increase in the value of LIDin the climbing range and a decrease in the value ofL/D nearmaximum lift, thus giving a dual increase inthe range of possible flight angles.
6. The air load on the 14.5 pmcent symmetricalauxiliary airfoil was about one fifth the total air loadon the combination at all angles of attaok; the pro-portional air load on the highly cambered auxiliaryairfoil was about the same at the-high values of thelift coefficient, but approximately half the total airlend at low values of the lift coefficient.
LANGLEY MIWORIAL AERONAmCAL LABORATORY,
NATIONAL ADVISORY COAMImEE FOR AERONAUTICS,
LANGLEY lhELD, VA., June 10,193$.
REFERENCES
1.Weick, Fred E., and Bamber, MillardJ.: Wind-TumdTasteof a Clark Y Wing with a Narrow Auxiliary Airfoilin DifferentPoeitions. T.It- No. 423, N.A.C.A.,1932.
2.Wenzinger,Carl J., and Harrie, Thomaa A.: The VerticalWind Tunnel of the National. Advieory Committee forAeronautic. T.Il. No. 387, N.A.C.A., 1931.
3, Weiak, Fred E., and Noyea, Richard ‘W.: Wind-TunnelIksearch Comparing Lateral Control Deviees, Particularlyat High Angles of Attack. X. Varioue Control Deviceson a Wing with a Fi~ed Amiliary Airfoil. T.N. No. 451.N.A.C.A., 1933.
CL degrees
(A) Am T.E. 16.0~t ahead of L,E+ 14.0percentabove aherd,3.2~.(B) Am. T.E. 11.5~t ahmd of L.E., 14.0Mat abeva ohord, 64P.
FIQUZE19.-0 ImmctdMca Wfth Olark Y, 14.sP21m3ntchord Wldferg.
.80 6=0”
+ ● = 5°
+ -— -- ,- fi--~
,I ,x \
–20~0-
.4 .8 .12-.02
.16~ for enfire wirig
(A) NA.OA. 00@ T.E. 11.6~t ahead of L.Ea 14.0~t above chord.(B) N_A.OA. Q T.E. 152pmantahead of L.E., 12.Opermnt above aherd.
Fxoum ~—Nmnal end chord mmments of the farce cm14.6parmnt chardamflfary afrfofk.
.-— —..—- . _. .__. . --. -—--- .— —. -
578 REPORT NATIONAL MWISORY COMilTITEE FOR AERONAUTICS
TABLE I.—CHARACWERISTICX AND CRITERICOLN~~O; mm~&C.A. 22,7.5PERCENT AUXILIARY WITH A
Pcafaf T&.EnofL~ fm
CL-0.7
g for
CL.”CD.1, ‘Ck.
Ahmd Above
Dwc#21n21
24B262626
m2220
22B22B2.322
21252’4
.232326
Pcr.yg ;
IL 5
27.5
2L 2
m o
Pt?mJ ;
14.0
M o
as
45
9.6
114116118
Hal137lW13412a
107109I@
lW10911111912a121
1461671,53
mlm114
lL 1la o7.6
10.410.4la 1a9K6
I&8Ii olL 7
121140121l&8la o18.4
12.110.Q10.0
10.09.99.9
$$46!I
3.843.61
tz3.37
6.19407481
3.M3.Ea&744.182.742.92
4023853.W
3.453.213.24
::3
.OEM
. OM3
. 01s
.0186
.019s0169
.0184
.0170
.0187
.ml
.01s3
.OISI
.0191
. ml
. Olw
.01.9
.017’4
.Olm
;%
.0m4
- HRL 478
L mlLrKrJL602LaLW2
L401L 374L3W
L 45L4ZIL 416L 510LW3L 6S1
L523L 646LtQS
LM=3LM3L622
#
7.5
m.7
19.3
lL 1
0.0
–25
7.4
!3-5
02$46
0
~+
.—
3.E43.793.@369
4.62
i%419
z&23.hs3.483.X3
.01P5
.0157
.0163
.ole8
.0218
.0177
. Oln
.0177
.01%3
.0185
.Om
.0191
L 401L340LWOL=
L&@LO?21L OML6?3
L640L 6181.ed.3L 676
242324B
23242424
25262s26
169114117lM
.121149Im146
137141142ml
TABLE II. CHAR.ACTE.RISTICSAND CRITERIcOLN&~O~~~NGA.C.A. 22, 11.0PERCENT AUXILIARY WITH A
