Wind-tunnel investigation of an NACA 23030 airfoil with various arrangements of slotted flaps

Document

. .- --- ---—.-—— . .

‘-+”” “-

.- - .. .... ....- TECHiTICAL NOTXS f “.

NATIONAL ADVISORY COMMIT!T!EZ FOR AERONAUTICS -.-= .- ,._.

, -- — --—— .— No. ?55 l -— -.

~ .— WIND-TUNNEL INVESTIGATION OF AN iT,A..!2.A. 23030 .— ., AIRFOIL WITH VARIOUS ARRANGEMENTS OF SLOZ!TED FLAPS By I. G. Recant Langley Memorial Aeronautical Labor&tor~ -.—. . .

, -- .“.

,;.:.

.-.. .

.,- . .. ---- : ---. . .- .:..--.” ,>==+ . ,\-u . -.

.— .-—..+= .:. .

. ..=” .+ ~.......

“!’ .. —.- .

.+ ’.-. ---- . . .: _. .-. . ..=- .- .;;:- ~c<:y- -- -=_-—-- “\v , --. --.+ 1“ -.

. .

b Washington .- ---- March 1940 NAT IONAL” ADVISORY COMMITTEE FOR AERONAUTICS —— TECHNICAL NOTE NO. 755 . .— WIND-TUNNEL INVESTIGATION OF AN. N.A.C.A. 23030 , -.

AIRFOIL WITH VARIOUS ARRANGEMENTS OF SLOTTED FLAPS -.

By I.

G. Recant . .

SUMMARY An investigation was made in the N.A.C.A. ~’- Ily lo- foot wind tunnel of a large-chordN .A.C.A. 23030 airfoil with a 40- and a 25.66-percent-chord’ slotted flap to de- t’ermime the section aerodynamic characteristics of the airfoil as affected by flap chord, slot shape, flap posi- tion, and flap deflection. The flap positions for maxi- . .

mum lift, the positions for minimum drag at moderate And — — high lift coefficients, and the complete section” aerody- ‘-- nanic characteristics of selected optimum arrangements are given. Envelope polars of various flap arrangements .+.

The relative merits of slotted flaps of are included.

different chords on the N.A.C.A. 23030 airfoil are dis- “- cussed, and a comparison is nade of each flap size with a — corresponding flap size on the N.A.C.A. 23021 and Z?3~l”2 .- -> airfoils.

The lowest profile drags at moderate lift, coeffi-.

— cfents were o%tained with an easy ‘eEtrance to the slot.

The 25.66-percent-chord slotted flap gave sonewhat lower -- drag than the 40-percent-chord flap for- lift coefficients less than 1.8, but the 40-percent-chord flap gave cors~id- erably lower drag for lift coefficients from 1.8 to 2.~” and a larger value of the naxinum lift coefficient.

The drag coefficients at moderate end high lift coeff-icients were greater with both sizes of flap on the N.A,C.A.

23030 airfoil than on either the N.A.C.A, 23021 or the N,A,C,A.

23012 “airfoil. The naxinum lift coefficient for the de- flections tested with either flap was practically inde- pendent of airfoil thickness.

.— INTRODUCTION The National Advisory Committee for Aeronautics has been conducting an extensive investigation of wing-flap k 2“”’ N, A. C.A. Technical Note. No. “755 . .

combinations for the purpose of improving safety and per- — formance. For take-off and initial climb, a wing-flap + combination capable of producing moderately high lift with low drag is desirable:. On the other hand, landing requirements probably make a devic~ with high lift and l vari~.blb drag desirable..

Furthermore, such a d.evico should give a “small increase in drag when tho flap i~ rfl- tracted and should give low opok~ting forces and a nini- mum change in pitching noment with change in flap deflec- tion.

Of the various types of flap Invostigatod by the N.A.C.A. , the slottod flaps are apparently most nearly capable of meeting those specifier.tions; modiun-chord and large-chord slottad flape for the N.A.C.A. 23012 and 23021 airfoils have b~bn 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 av~il~ble for the aerodynamic design t ,vof’ slo-&ted flaps on airfoils of any probable thickness.

MODELS Plain Airfoil The basic airfoil, which WGS built of lanineted pino to the N.A.C.A.

23030 prafile, has a 3-foot chord and a 7-foot span. The trailing-edge section wma nad~ ut6i3Y removable so that it can be readily re?lacod by different flap arrangements.

The okdinatos for this airfoil n.rc ~ gtven in table 1.

.— Slotted-Flap Arrangements .— .

.-, ll!he slot shapes find flaps wore built of lnninated b .— pine . The slot shapes were bolted to the.ruain airfoil in place of the plain trailing edge, and the flaps were , mounted on the airfoil by means of special-fittings that permitted wide variation in location with respect to the slot lips. The basic airfoil, tho flaps, ~.nd the slot shapes were fair and were mad6 to a tolerance of AO.015 inch.

— d TWO flap”s.w$re tested, one with a chord 40 .— Iuk12&- - N.A. C. A.’’ Technical Note No. 755 3 ,* .

., . .

.“perce-nt of tha wing chord and the other wi”th a chord -25.66 percent of the wing ‘chord”. These flaps are not geome.tri- .4 tally similar”, but both” ware designed. With a small nose radius to. keep the width o.f the breaks in the lower surface .-of the airfoil narrow “with”the flaps retracted. Tho up- l per surface. of the forward portion of each flap is. an arc ..ofw circle tangent to the lower surface of the slot lip.

(See figs. 1 and 2.) Both flaps are designated 1 because they are comparable with flaps 1 used with the N,A.C.A.

23012 and 23021 airfoils (references 1 to 4). For conven- ience, the 40-percent-chord flap will hereinafter he re- l!wf~e-ch~rdll flap and the 25.66-percent- ferred to as the chord flap will be referred to as the ‘Imedi.um-,chord!. fl.ap.

Slot shapes.- Two types of slot shape were used. with + each sizo of flap. These types are designated a and h.

(See figs. 1 and 2.) Sha~es a and b for the wide-chord and b flap are not geometrically similar to shapes o, for. the medium-chord flap.” - Shapes a for,. hotli frtip SiZOS, however, were”.desi’gned to give a minimum break in tho;~ower surface of the .&irfoil with the flaps retracted and shapes b are. comparable with shape h of reference 1, which gave the. lowest drag for high and interme”diatc lift- coAf- —-.—— ficient”s. The slot lips for each flap size zir.e longer than ‘ the sl’ot lips for” corresponding flap sizes on ,the N.A.C.A, ‘23012. and the N.A.C..4. 23021 airfoils. (See references 1 “ . .

, , to 4.)

, :, : ,, .- . .

ms”Ts . --- . . i ‘ .- . .

The m’odel was mounted .vertically iri the closed test ‘- section of the N.A.C.A. 7- b,y 10-foot wind tunnel (refer- ~ncos ,1 and 5) so that it completely spanned.the .,jet ex- cept ‘for small clearances at each end. The ‘main ‘air-foil was rigidly attached to the balance frame b~ torque tubes, which extended through the upper and the lower boundaries Tho angle of attack of the model was set of the tunnel.

from outside the tunnel by rotating the torque tul$es with a calibrated drive. Approximately two-dimensional flow is obtained with this type of installation and the sec- tion characteristics of the model under test can be deter- mined, 6.

All tests, exc”e~t those to determine ‘the effect of- scale, were made at a dy~amic pressure of 16.37 pounds 8- per square foot, corrospondin,g to a velocity of approxi- 4.

N. A. CoA. Technical }TOtO EO. 755 mately 80 miles per hour under standard atmospheric condi- *, tions and to an average test Reynolds Number of about & 2,190,000. Because of the turbulence in the wind tunnel, the effective Reynolds Number, Re, (referenc~ 6) was approximately 3,500,0.00.

Yor all tests, the value of R.

l is based on the chord. of the airfoil with the flap re- tracted and on a turbulence factor of 1.6 far the tunnel.

Plain Airfoil The lift, the drag, and the pitching moment of the basic airfoil were measured over the complete angle-of- attack range from -6° to the shall.

Slotted-Flap Arrangements Tests were first made with each size of flap and both slot shaps to determine the effect on the drag of the breaks in the wing surface at the slot entranco and the- l slot lip when tho flap ‘was retracted. Thi. offeot of the flap hinges with the flaps in the retracted position was also investigated. Tests were then made with each flap size and each slot shape at various fle.p deflection~ anii positions to determine the optimum peths from consi~era- tions of low drag at--small flap deflections and h~gh Z1.ft at .Iarge flap deflections. The wide-chord and the nedlun- chord flaps were deflection fnom O 0 to 50° and fron 0° to 600, respectively, in 10° increments. In all cases, lift, drag, and pitching moment were.measured through an e.ngle- of-attack range from -60 to the stall.

Scale-effect tests were also fiade of the med”~um-ti”hord flap in its o~timum position for qqxinum lift when de-- fleeted 40°.

RESULTS AND DISCUSSION .

Coefficients All the test results are given in standard” section nondimensional coefficient fmrn corrected for tunnel-wall effect and turbulence as axplaified in reference 1“.

cl section lift coefficient (1/qc)* N.A. C .A. Technical Note- No. 7“55 5 ,.

section profile-drag coeffici, en;’ >= Cd.

.~do/qc) .

. .

section pitchfng-moment coefficient about Cm(a. c.)o aerodynamic center of plain airfoil : ‘ ‘m(a. c.)o/~c2)m .* where .,

,F=tiin lift, ““ “

,.: saction profile. “drag. do se’ction pitching.moment.

W“a.c. )o — ,.

dynamic pressure (pV2/2).

.- chord of bh?ic airfoil with flap fully re- c .. .

tracted.

and ., angle of attack for infinite aspect ratio?

. . . . L flap. deflection.

a m flap chord.

,.- i ...

.- { . ...

-..

. .

Pr~cision .

,...

# The accuracy. of the various measurements in the tests is believed to be within the following limits: —- -.

--- =0.0006 *o.1° cd a. --------- O(cl’= “’ 1.0) *()*03 ----.- c~max --- -+o,oo2- +0.003 Cao(cl = ?95) c~(a. c.)o ‘- --- ---- -- --- -- *o.2° af +0.0003 Flap position --- +0.00Ic .

A correction for the effect of the flam-hin~e fit- tings has been applied to the data for the ~lap-~etracted conditions. This correction amounted to about 5 percent of the minim’um drag of the plain airf,oil. No attempt was made to determine the effect of the hinges with the ‘flaps 6 N. A. C,A. Technic.al.+LQt~ No. 755 ~, The rol’ative, merits of the v&Tious flap ar- -.

de flectsd.

rangements, however, are believed to ho inapprociahly af- . .

fected because the’ -smwfittings w-arousod throughout, tho tests for a given glap size.

, Plain Airfoil Aerodynamic charactoristlcs.- The cogpleto” section aerodynamic characteristics of the plain N.A.C.A. 23030 .

+ As these data have been airfoil are given in figure 3.” discussed in referocce 7, no further comnent is required.

Effect on profile dra~ of breaks in surface of air- foil due to slot.-. .The effect of the breaks in the airfoil surface on the drag coefficient with the f-lap retraced is shown. in f’igure 4 for the’ wide-chord flap and in figure 5 for the medium-chord flap. The variation of i’ncremont of was Irregular in l lmost profile-drag coefficient (Acdo) all cases. With only the slot-lip of the wide-chord-flap .!

arrangqrnent unsealed, Acdo ,was negligible below a lift t co-effictent of 0.6 and rose to a value of 0.0018 at cl = \ .

Acdo due 0.8. In the case of the medium-chord flap, the i to this break was too small to measure.

-: !

When the breaks in the upper md tho lower surfaces L Acdo varied caused %Y wide-chord flap l-a were unsealed, ,., while the breaks caused by nedi.um- . .

from 0.0006 to 0.0035, chord flap l-a. gave values of Acdo varying from about .

for the 0.0004 at : cl = O to O at c1 = 0.8. The ACdo wide-chord flap l-b unsealed was about 5 times that for wide-chord flap l-a, E+? the Acdo with the medium-chord flap l-b unsealed was about 10 times that of the corres- Much of the drag increnent duo ponding l-a arrangement.

to the breaks in the wing lower surfaco with ei.th.erslot shapo with the flap retracted can probably be elimine.ted by thb -use of an auxiliary flap or a door to seal the , breaks.

Slotted-Flap Arrangements .

~ Daterm$natlom. of optimun arrangements for naxinum “lift..- The data in this .section are presen~cd a6c ontours .

6 to 9) P$ $lap-nose position-relative tw tho slot (figs.

li”p. f.~rconstant va.lue,s, o~ lift coef.ficie.gt. Zhes.e c.og- N. A. C.A. Technical Note No. 755 ,* tours were prepared from the results of tests at numerous ,.

The nose of the flap positions for each flap deflection.

., is defined as the point of tangency 6f the leading-edge arc and a line perpendicular to the wing chord line when (See figs. 1 and 2.)

the flap is “in the neutral position.

IJrom these contours, it should be possible to select the best flap path from considerations of.maxfmum lift coefficient for each flap deflection. If, for structural reasons , it is impossible to use the lest aerodynamic path, the contour? permit the evaluation of the effect of any deviation. Complete section aerodynamic character- istics of selected optimum arrangements for each flap de- flection are given in a later section.

Contours of maximum lift coefficient for the wide- chord flaps l-a and l-b are given in figures 6 and ‘i’; fig- ures 8 and 9 give the contours for the medium-chord flaps l-a and l-b. A number of these contours, including some are unclosed %ecause q >arge..

for high flap deflections, enough area was not covered by the tests. It is believed, however, that the range tested will include any paih choson for mechanical practicability. In any case, the contours would close back of tha lip.

The wide-chord flap was deflected fron lCjO to 50° and These ‘ the medium-chord flap was deflected from 10o to 60°.

,ranges, although too narrow to establish definitely the ultimate maximum lift coefficient of each flaps are the same as those, investigated for ‘the slotted flaps on the The maxi- N.A.C.A. 23012 and the N.A,C.A. 23021 airfoils.

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 wing chord ahead of and 6 percent below the slot lip. Med’ium- chord flap l-a gives a naximun lift coefficient of 2.59 when deflected 60° and located 2.5 percent of the wing The nax- chord ahead of and 4 percent below the slot lip.

imun lift coefficient given by medium-chord flap l-b is 2.68 when deflected 60° and located 0.5 percent of the wing chord %ehind and 4 percent below the slot lip.

The contours of maxinum lift coefficients at flap de- flections of 10° and 200 for all flap arrangenetits are in- because the optimum cluded to make the data more complete, flap positions for these deflections will probably be chosen from considerations of low drag ~d practic.@bilitY of mechanical operation.

N,. A. G.A. Technical Note No. 755 ..

profile Determination of optimum arran~ements for l ,- The optimum positions flrom considerations of low &!213”- ,.

drag at moderate lift coefficients likely to be used for take-off were chosen from contours of flap-nose posittou 1.0 and 1.5 for the 10° and for constant drag at’ c1 = Figures 10 and 11 show tho the 20° flap deflections.

contours for the wide-chord f-laps l-a and 1-B; and f%-guree 12 and 13 give the contours for the medium-chord flapa Most “of these contours do not close, but ‘it l-a and l-b.

is belisved that sufficient positions havo been lnvosti- g.ated to cover, any probable flap path.

Insufficient data were available to give contours nt at cl = 1.5 Ct = 2*O, %ut the position for minimum Cdo is also the position atwhich cd. is and ‘ 8,f = 20Q &f & = 2.0 and 20° for both the wide- minimum at C .1 The minimum prcfilo drag and the medium-chord flaps l-b,.

= 300 is higher when than when 6fl= 20° at = 2.0 c1 6f * -.

for both flap .sizes.

-. r— l aerodynamically, for the 10° The best flap positions, and the 20° flap deflections are iudicated by figures 10 to 13* The figures also permit the evaluationof the det- rimental effect due to deviation from these positions.

Section, aerodynamic characteristics of selected oPtf- mum arrangements .- The optimum positio}ls for ee.ch flap ‘arrangement were selected from considerations of low drfag at the 10o and the 200 flap deflections and of maximum The com- lift coefficient at the higher flap”deflections.

plete aerodynamic characteristics of these optimum Poa~- tions are given in figures14 to 1’7.” These figUreS also include data for positions that aro not on the best aero- dynani+c path in order to make pos,sihle the estimation of the characteristicsof a path, the reproductiori of wh~”ch The table In each figure would be structurally simpler.

The gives the flap position for each-flap deflection.

path for each flap arrangement plotted in the sketch on the figures is a structurally feasible one that C1OSO1Y follows the aerodynamic optimum. These compromise paths llsclect~dll optimun are hereinafter referred to as the .* ~ paths. The characteristics given are typical and data for positions other than those shown aro available upon request.

.- l Envelope ConParison of selacted opt.inum arrangements.- polars, obtained f~om figures 14 to 17, for both flap arc shown in fig- sizes, each with slot shapes a and b, ,., N. A. C.A. Technical. l$ote-N&. ”755 9 ., A comparison of these polqrs indicates ures 18 and 196 ,.

that , except at .1OW values of the ‘lift coefficient slot- -# ted flap l-b is better from consider&ions of drag than On this basis~- the wide-q,hord “ l-a for both “fla~ sizes.” flap l-b is more suitable for take+off than l-a for lift * the medium-chord flap l-b is coefficients above 0.’7, and %etter than l-a at lift coefficients greater than 0.4.

It should be-noted that, below a lift coefficient of about 0.5, the plain wing has less drag than any of the arrange- ment with the flap deflected. “A”door to seal the breaks in the lower surface of the wirig would thoreforo maie all the arrangements approximately equivalent to the plain wing at the lower ‘values of ct.

Slotted-flap. l-b is superior to l-a for either the .wide- or th,e medi~-chord flaps when they are conpared on “a tiasis of increnent of naximum lift coefficie-nt for .a given flap deflection, the flaps in all cases heiqg ~oved along the .sel”ected”optfnun path”s. (See figs. 20 and 21. ) ..-.

. The diving monent at the sane lift coefficient is greater for slotted flaps l-b than for slotted flaps l-a,, the diff,enence being nore pronounced for the wide-chord * flap than for the mediun-chord flap (figs. .14 to 17).

Comparison of slo~ted flaps of dlfferen”t chotd~-,’.A comparison of the wide-chord flap l-b and the nediu~-chord flap l-b is. made in figure 22. The nedlun-chord fla,p gives. a lower drag than tho wide-chord flap at lift coef- ficients lower than 1.8 and would therefore he more dosir- ahle for take-off in this range.

The wide-chord flap, however, would be more suitable for take-off for a re.nge of lift coefficients from 1.8 to about 2.5. This flap also gives a higher value of naxinum llft Coefficient for “ the range of flap deflections tested. The pitching-moment coefficient gives’by the wide-chord flap is greater, how- ever, than that given by the ma&ium-chord,flap at the same lift coefficient.

l The variation of increment of maximu~ lift coeffi- .cidnt with flap chord,for a flap deflection of 50° is shown in figure 23,; The fairing of this curve is, of .

course, arbitrary, but the indications are that a great-er gain in increnent of maximun lift may be expected by in- .

“ creasing the flap chord fro,m 10 yercent to-25,66 percent This result would than from 25.66 percent .to 40 percent.

be in agreenentwith.the results for the slotted flaps of ,.

different chord on the N;A.C.A. 23012 airfoil (ref.8rence 10 N.A,.C .A. Tec~ni.c~l Note ,No.,755 J.

2). There a_pparently”is no justification for. using the ., .- wide-chord flap mere-ly because it gives a somawhat higher l .

c1 since the hinge moment, being proportional to the ma,x3 square of ,the flap chord, would be coneidernbly larger wft;l this. flap than with tl+e medium-chord flap.

% ,, . .

Effect of scale on ‘incr’emont of maximum lift coeffi- cient.- The effect of “scale on the Increment of maxinun lift coefficient for the medium-chord flap 1-11 is shown in ‘figure 24. The increment of cl Increases with n ax increasing scale from Re = 1 to about 1.5 nillion. At occurs.

higher Reynolds Numbers, no iqcreaso in ACImax The curve indicates that the increment of nuxinun lift coefficient may be considered independent of scale in the 1,500,000 to 3,500,mo.

range of Reynolds Nunb.crs from and medium-chord slotted flaps Comparison of wide- on airfoils of different thickness--- Tho results of the present tests together with the results ropor%ad in rof- erencos l,to 4 nake possible an evaluation of the effect C of airfoil thickness on. the charncteristlcs of airfoils Such an evaluation is made equi~ped with.slotted. flaps.

in figure 25, which gives the envelope polars for the wide-chord flap l-b on the N.A.C,A* 23012 (refor~nco 2), N.A.C.A. 23021 (reference 4)$ and N.A,C.A. 23030 airfoils.

As nay be expectd, the drag at a .gfven lift coefficient increases as the thickness of the airfoil increases. It is of interest to note, however, that the maxinum lift 500 and the drag at that lift coef- coefficient at ~f = ficient are about the ecme for the three airfoils.

A comparison of medium-chord flap 2-h on t-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 is made in figure 26. Here again the drag .for ~.given lift coefficient increases with wing thickness. Alt!~ough the .

m~ximum lift and the drag nt this lift arc about the smie for the 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.

:<C1 The for the plain airf”o-ils subst-~-nti.nl-ly-de- . . . .

max T creases as the aibf,oil thickness increases (referenco ‘7), . .

and this result might bo expected for airfoils with slot- .- — .

N.A.C..A: Technical Note No. 755 . .

ted flaps. Inspection of figure 27, however, shows that the maximum lift coefficient of the slotted-flap airfoils . .

are not greatly affeoted by wing thickness. The Ctnax of the air”foile with the: medium-chord” slotted flap, decraases l about 5 percent with an increase in thickness from 12 to 30 percent, as compared with a decrease of about 30 percent for the plain airfoils over the sane range of thickness.

In t,he case of airfoils with a wide-chord slotted flap, no change in maxinum lift .coefficient occurs with increasing . ..— wing thickness.

If structural requirements, -nece”ss”itcte a thick seat’ion, the use” of” slotted flaps will therefore largely eliminate any loss in rnxinum lift coefficient that is associated with the thick section when used. wfthout ,flap~.’, Similar results have been obtained with split flaps (ref,e’rehce 7).

— —.— — ,,.

CONCLUDING REMARKS ,...

. .

An easy slot entrance was better than a sharp entrance.

with l)oth the 25.66-percent-chord flap and the 40-percent- chord flap, except for low drag with the flap retracted.

The wide-chord flap was better than the medi,um-chord fla~ from considerations of maximum lift coefficient and low drag a% lift coefficients of 1.8 to 2.5, although the gain in maximum lift coefficient was relatively small. Both flap sizes gave progressivcily lower values of drag coefficient at moderate and high lift coefficients on the N.A.C.A.

23021 and 230.12 airfoils than on the N.A.C.A. 23030 airfoil.

The maximum lift coefficient with either flap-was approxi- mately independent of airfoil thicknees.

Langley Memorial Aeronautical Laboratory, National Advisory Committee for Aeronautics, Langley Field, Vs., Pebruary 28, 1940.

N. A. C.A. Technical Note No.. 755 ,.

REFERENCES .

Wind- qunuol 1. Wenzinger, Carl J., and Harris, Then.as A.; Investigation of an N.A.C.A. 23012 Airfoil with- Various Arrangements of Slotted Ylaps. .~.R. No. 664, N.A.C.A,., 1939.” Thomas A. : ;find-Tunnel Investigation of an 2. Harris, N.A.C.A. 23012 Airfoil with Two” Arrangements of a Wide-Chord Slotted Flap. T.N. ,No. 715, H.A.CoA., .

1939.

Wind-Tunnel 3. W@nzinger, Carl J., and Harris, Thonas A.: Investigation cf an N.A.C.A. 23021 Atifoil with Vari- ous Arrangements of Slotted Tle.ps.

!l!.R.HO. 677, — N.A.C.A. , 1939.

4. Duschik, Frank: Wind-Tunnel Investigation of an N.A.C.A.

23021 Airfoil with Two Arrcmgenents of a 40-20rcf3nt- .

Chord Slotted Ylap. T.N. ~00 728, N.A.C.A. , 1939.

,, 5. Harris, Thomas A.: The 7 by 10 Foot Nind Tunnel of the * National Adviso”ry Conmittee for Aeronautics. T.R.

No. 412, N.A.C.JL. , 19Z”1.

Airfoil Sec- 6. Jacobs, Eastnan N. , and Sherman, Albert: tion, Characteristics as Affected by Variations of–the Reynolds Nunber. T.Il. No. 586, N.A.C-.A,, 1937=” Wind-Tunnel 7. Wcnzinger, Carl J. , and Harris, Thomas A.: Investigation of N.A.C.A. 23012, 23021, and 23030 Airfoils with Various Sizes of Split Flap. !?.R. No.

668, N.A.C.A. , 1939.

N.A.C.A. Technical Note No. 755 13 Table I Ordinates for N.A.C.A. 23030 Airfoil (Stations and ordinates in percent of wing chord) * Ord late Station Upper Lower , o 4.82 o 1.25 7.37 -2.63 2.5 8:90 -4.27 5 11.05 -6.54 7.5 12.5? -8.28 13.68 -9.65 15 15.20 -11.52 20 16.07 -12.61 25 16.46 -13.20 30 16.57 -13.46 \ 15.89 -13.13 50 14.38 -12.11 60 12.34 -10.47 70 9.86 -8.42 80 7.03 -6.09 3.8? -3.40 95 -1.g6 2.15 .

-* 100 ,315 315 —

L

L.E.

radius: 9.90. Slope of radius through end of chord: 0.305.

r , /p .mlc thick

I

~.599c ~..mc —J (a) Flap 1-L (b) Flap l-b ‘Nw-o 1.- Saotionn of E. A.C.A. 23034 airfoil with uT8&ymnt8 of 0.4QU Eloi%d flap 1.

(a) F@ra 3.- .%otim ,cmd~mia Ohnet+ristim of N. A.C. A. 23B0 plain airfoil.

(d Flip l-m. (b) tlm l-b F- 2.- Emtims of Ii. i.e.t. S3UFJ0 airfoil *MI grmnymb.

of 0.2?.% olottcd fl.p i.

,,, I I ,, I ,“, -.

., .-.

N.A.C.A. Technical NoteHo. 755 ..

Fig. 6 .- .

+=74==’ ‘ ‘ ‘ ‘“’ ‘i{~ ‘--”

\/l!!-Hl- 7TTTW rmi7T7

I .

(a) 6f = 10°.

.- (b) 6f = 200.

(d) 6 = 400.

(e) 6$ = 500.

Figure 6.- Contours of flap location —- The 0.40c slotted ‘0’ c%ax” flap l-a.

— -.

N.A.C.A. Technical Note No. 755 ..

.-.

. .

Its /2 4 o r%rcenfBw/ngcb a+ (d) ~ ‘.” ‘- “ -= . . . .— ) .

\ /lmll Lwk

/6 f2 8 4 0 f’ercenfwltig cfi.rd (=) — .

.- —.

(a) 6f = 100.

(b) bf =20°.

(e) 6f=500.

Figure 7.- Contours of flap location The 0.40c slotte-d- ‘or “klx” flap l-b.

-- .- Pe,-enfw;ng C/lord (c) -.

Fig. 8 N.A.C.A. Technical Note No. 755 .

.- .— .

-- - (a)6f=100. (b) 6f=200. (c) 6f=300. (d) 6f=400. (e) 6f=50G. (f) 5f=600.

Figure 8.- Contours of flap location for c~max. The 0.2566c slotted flap l-a.

N.A.C.A. Technical Note No. 755 Fig. 9 — .

___ . .

. .

.=” — .

._.- ---- .

~aj tif = 10°. (b) 6f = 20°. (c) bf = 30°. (d) bf = 40°. (e) bf = 500. (f) 6f-= 600.

% Figure 9.- Contours of flap location for c1 . The 0,2566c slotted fIap l:b, max N.A.C.A. Technical Note No. 755 -—F’ism. 10. 11 .

., . .

— -.

I

Figure 10.- Contours of flap location for} Figure 11.- Con’cow-s Of flap location for cd .The 0.40c slotted flap l-a.

cd .The 0.40c slotted flap l-b.

o o 12,13- Fig8.

N.A.C.A. Technical Note No. 755 .- .- .-— _- . A .

I (a) fSf= 10°; cl = 1.0. (b)6f= 20°;ct = 1.0.

(a)6f=100}ct= 1.0. (b)6f=100;ct= 1.5.

. . . . . _ ..

Figure 12.- Contours of flap location for Figure 13.-Contours of flap looation for Cdo.

~do.Th8 0.2566c slotted flap l-a. The 0,2566c Blotted flap l-b.

—.

retii~ MotO HO. 755 . . ..C. A.

FiK. .14 ..

. .

— -- l ,- c--— -...

: .

.26 .

.24 .

.22 .

.- ,.

. -_,> — .— .—- — I I I r I I 1 --- , ..+ = I I I ,U.q I I 1 I I.

1-1’ r -1 I I I t I t I I I I t II I 1 I I I I i I I I I ! I I 1 I

m

-= ., .

.- ...

1 , , , 1 , , 1 , [ J 9.Z02Z2A 262830 Section Iiff coeffiiciemf, C, Figure 14. - Section aercdyuamia ohm-actaristics of X.k.C. L. Z3CW alrfail iith 0.40c slotted flap l-a. - .“”Fik. M” N. A.C. A. Technical Hote Ho. 7’S3 .. .=....— . .

., ..” -.

— —.

_ .- .-. .= I I ?1 I I I Iu II I II I I 1 I .— a -- .+ .

, , . I , , , , I VI 71 I I I I t 1 r 1 1 1. 1 1 I 1 r x 1 .o--- -. .

: Figure 15. - Section aerodymmio oharmteristios of E. A.C.A. 23030 &foil with 0.400 dotted flap l-b.

e . .

,, H.4.C. A. Teohnical Note Ho. 7E5 Fig. 17 ..

B“ co J $“ -./ ,.

~ -.2

8 +-l-H

> ..3 t -.

.— , , # 1 1 1 # I 1 I E 1 I 1 1 I 1 I 20/ t f I I I I I I I I I I i r I I .

-,- .

F “ .

E A 4-1 . 1 1 1 4 ,

~lT~lTHl I

-!4 72 0 .2 .4 .6 B LO L? .L4 &.f& .&7 .22 2.4 26 2B 30 .SeCtim lift coeffic;tif, cc Figure 17. - Section aurcdynamio clmaoteristfca of F. A.C. A. 23030 airfoil with 0.z56& aIotted flap i-b.

M [,25 li. A.C. A Te ..

t I I # , r i I I I I I I 1 I I I I I I I i , , , I -1 I , / !

I !

HH

/ < G-” ~.

.; “ & al” o c1 b.

o +5 4“ ~ —--- $“ c o ,.

$ ,.

.— — S&ion fiff “w eflciem’, c, Coxperioon of 0.40c dotted fIapm on ii. A.C. A. 23030 airfoil.

Figure 18. - — .

.30 .28 .a5 .24 .22 ~“ .4- .

-&-Ozo .: ,.- ~./8 o ~./6 p ?./4 S’ e ?./2 . Q 8 fo ~. .

u .

‘.08 .06 .

,.–. >--F I 1 I 1A ,- .04 / A -- / 1 1 1 { 1 1 1 I t 1 -t---- - -- .

IL-L – z 7 z - “ - “ . .02 -E{-+ ~--+--w !

I , T I I I I ! -r I J I > -!4 T2 O .2 .4 .6 .8 LO f.2 L4 L6 1.8 2.0 2.2 2.4 26 28 3.0 Seci+bn lift coeffici~f, c, Figre 25. - Comparison of 0.400 Blotted flap l-b on H.A.C. A. 2W.YJ, 23621; and 2301Z airfoilm.

x.; .?. A. Technical Mote Ho. 75!3 Fig. 19 .

— ,- .- ..

— — ..-.

.— — ,.

, Fiswe 19.- Coqarlmn of 0.2%5c slotted flapo on H. A.C. A. Zl@30 airfoil.

“.

C* . .

Increment of sec+ion maximum I 1’ i I 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.

N,A,C.A. Technical Note Mo. 755 Flga. 23,24 9- ., -. — u — -, .—

m

— _- .

-- Figure 23. - Variation of increment of section m.e!dmum lift coefficient with fl.a chor~. Slotted flape l-b on H.A.O.A. 2W30 tirfoil.L3f=X — —---— Effec?Yve Reynobk Number,fi.

.- Figure a4.- Scale effeot cm eeotion ma.xlmm - ft ooefflclent for $.A.O.A. 220% airfoil wi+tiand rlthout 0.26660 slotted flap l-b.

.- H. A.C. A. Tcohuiod Hoto Ho. 765 Fis. 26 r — *.

r —.

.-— 1 I I I I I I I l-l I I Lo 1.2 /.

?4 =2 O .2 .4 .6 .8 Section Iif+ coefficienf,c, Figure 26. - Coquriaon of 0.25660 slotted fiapu on U. A.C. A. 2M12, 2M21, SJM 2ZJXIII airfoils.

(i -1 .

1, I .

i

II i;