NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS · national advisory committee for aeronautics report no. 723 wind-tunnel investigation of naca 23012, 23021 and 23030 airfoils equipped

NATIONAL ADVISORY COMMITTEE

FOR AERONAUTICS

REPORT NO. 723

WIND-TUNNEL INVESTIGATION OF NACA 23012, 23021

AND 23030 AIRFOILS EQUIPPED WITH

40-PERCENT-CHORD DOUBLE SLOTTED FLAPS

By THOMAS A. HARRIS and ISIDORE G. RECANT

/

REPRODUCED BY

NATIONAL TECHNICALINFORMATION SERVICE

U.S DEPARIMENI Of COMMERCESPRINGFIELD. VA 22161

1941

https://ntrs.nasa.gov/search.jsp?R=19930091801 2018-06-09T04:44:51+00:00Z

AERONAUTIC SYMBOLS

1. FUNDAMENTAL AND DERIVED UNITS

Metric English

Symbol ft (or mi)

Unit Abbrevia- Abbrevia- * "tion Unit tion

Length ...... l meter .................. m foot (or mile) ........... •Time ........ t second ............... s second (or hour) ...... _ c (or hr)Force ........ F weight of 1 kilogram ...... kg weight of 1 pound ...... _

Power ....... P horsepow (metric) ............... horsepower ........... hpfkilome_er per hour ...... kph miles per hour ......... mph

Speed_ V [meters pe second ........ mps feet per second ....... fps

2. GENERAL SYMBOLS

W Weight--: mg v Kinematic viscosityg Standard accelera*tion of gravity--9.80665 m/s _ p Density (mass per unit volume)

or 32.1740 ft/sec 2 Standard density of dry air, 0.12497 kg-m-_-s 2 at 15 ° Cm Mass -W and 760 mm; or 0.002378 lb-ft- 4 sec _

g Specific weight of "standard" air, 1.2255 kg/m _ or1 Moment of incrtia--mk _. (Indicate axis of 0.076511b/cuft

radius of gyration k by proper subscript.)Coefficient of viscosity

3. AERODYNAMIC SYMBOLS

S Area i_ Angle of setting of wings (relative to thrust line)S_ Area of wing it Angle of stabilizer setting (relative to thrustG Gap line)

b Span Q Resultant momentc Chord _ Resultant angular velocity

b2 V1

A Aspect ratio, _ R Reynolds number, p _- where 1 is a linear dimen-

V True air speed sion (e.g., for an airfoil of !.0 ft chord, 100 mph,1 _z2 standard pressure at.15 ° C, the corresponding

q Dynamic pressure, _pt Reynolds number is 935,400; or for an airfoil

_z of 1.0 m chord, 100 mps, the correspondingZ Lift, absolute coefficientCL=q N Reynolds number is 6,865,000)

D Drag, absolute coefficient CD_-D a Angle of attackq_ Angle of downwash

Do Profile drag, absolute coefficient cDo_D ° ao Angle of attack, infinite aspect ratioq_ a_ Angle of attack, induced

D_ a_ Angle of attack, absolute (measured from zero-D_ Induced drag, absolute coefficient CD_--qS lift position)

Dv Parasite drag, absolute coefficient CD_-: D_ _/ Flight-path angle

CG Cross-wind force, absolute coefficient c

2626 °

S

REPORT No. 723

WIND-TUNNEL INVESTIGATION OF NACA 23012, 23021

AND 23030 AIRFOILS EQUIPPED WITH

40-PERCENT-CHORD DOUBLE SLOTTED FLAPS

By THOMAS A. HARRIS and ISIDORE G. RECANT

Langley Memorial Aeronautical Laboratory

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

HEADQUARTERS, NAVY BUILDING, WASHINGTON, D. C.

Created by act of Congress approved March 3, 1915, for the supervision and direction of the scientific study of the problems

of flight (U. S. Code, Title 50, Sec. 151)• Its membership was increased to 15 by act approved March 2, 1929. The members areappointed by the President, and serve as such without compensation.

VANNEVAR BUSH, Se. D., Chairman, RORERT E. DOH_TY, M. S.,

• Washington, D.C. Pittsburgh, Pa.

GEORGE 3". MEAD, SC. D., Vice Chairman, RO_E_T H. HINCKLEY, A. B.,

Washington, D.C. Assistant Secretary of Commerce•

CHARLES G. ABBOT, SC. D., J-ERO_IE C. HUNSAI_:ER, Sc. D.,

Secretary, Smithsonian Institution• Cambridge, Mass.

HENRY H. ARNOLD, Major General, United States Army, SYDNEY M. KI_AUS, Captain, United States Navy,

Deputy Chief of Staff, Chief of the Air Corps, War Bureau of Aeronautics, Navy Department.

Department. FRANCIS W. REICHELDERFER, SO. D.,

GEORGE H. BRETT, Major General, United States Army, Chief, United States Weather Bureau°

Acting Chief of the Air Corps, War Department. JOHN H. TOWERS, Rear Admiral, United states Navy,

LYMAN J. BRIGGS, Ph. D., Chief, Bureau of Aeronautics, Navy Department.

Director, National Bureau of Standards• EDWARD WARNER, SC. D.,

DONALD H. CONNOLLY, B.S., Washington, D. C.

Administrator of Civil Aeronautics. ORWr_J_ WRIGHT, SC. D.,

Dayton, Ohio.

GEORGE W. L_WIS, Director of Aeronautical Research S. PA_ JOHNSTON, Coordinator of Research

50HN F. VICTORY, Secretary

HENRY J. E. REID, Engineer-in-Charge, Langley Memorial Aeronautical Laboratory, Langley Field, Va.

SMITH J. DEFRANCE, Engineer-in-Charge, Ames Aeronautical Laboratory, Moffett Field, Calif.

TECHNICAL COMMITTEES

AERODYNAMICS AIRCRAFT STRUCTURESPOWER PLANTS FOR A_RCRAFT AIRCRAFT ACCIDENTSAIRCRAFT MATERIALS INVENTIONS AND DESIGNS

Coordination of Research Needs of Military and Civil Aviation

Preparation of Research Programs

Allocation of Problems

Prevention of Duplication

Consideration of Inventions

LANGLEY MEMORIAL AERONAUTICAL LABORATORY AMES AERONAUTICAL LABORATORY

LANGLEY FIELD, VA. MOFFETT FIELD, CALIF.

Conduct, under unified control, for all ago_ncies, of scientific research on the fundamental problems of flight•

OFFICE OF AERONAUTICAL INTELLIGENCE

WASHINGTON. D. C.

Collection, classification, compilation, and dissemination ofscientific and technical information on aeronautics

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

HEADQUARTERS, NAVY BUILDING, WASHINGTON, D. C.

Created by act of Congress approved March 3, 1915, for the supervision and direction of the scientific study of the problemsof flight (U. S. Code, Title 50, Sec. 151). Its membership was increased to 15 by act approved March 2, 1929. The members areappointed by the President, and serve as such without compensation.

VANNEVAR BUSH, SC. D., Chairman, RORE_T E. DOHERTV, M. S.,Washington, D.C. Pittsburgh, Pa.

GEORGEJ'. ME/kD, Sc. D., Vice Chairman, ROBERT H. HINCKLEY, A. B.,Washington, D.C. Assistant Secretary of Commerce.

CHARLES G. ABBOT, Sc. D., _ER0_E C. HUNSAKF_I_, Se. D.,

Secretary, Smithsonian Institution. Cambridge, Mass.

HENRY H. ARNOLD, Major General, United States Army, SYDNEY M. KRAUS, Captain, United States Navy,Deputy Chief of Staff, Chief of the Air Corps, War Bureau of Aeronautics, :Navy Department.

Department. Fm_Ncis W. REICHELDERFER, SC. D.,GEORGE H. BRETT, Major General, United States Army, Chief, United States Weather Bureau.

Acting Chief of the Air Corps, War Department. JOHN H. TOWERS, Rear Admiral, United States Navy,LYMAN J. BRIGGS, Ph. D., Chief, Bureall of Aeronautics, Navy Department.

Director, National Bureau of Standards. EDWARD WARNER, Se. D.,

DONALD H. CONNOLLY, B.S., Washington, D. C.

Administrator of Civil Aeronautics. ORVILLE WRIGHT, Se. D.,Dayton, Ohio.

GEORGE W. LEWIS, Director of Aeronautical Research S. PAul. JOHNSTON, Coordinator oF Research

JoHn F. VICTORY, _ecretary

HENRY J. E. REID, Engineer-i_-Charge, Langley Memorial Aeronautical Laboratory, Langley Field, Va.

SMITH J. DEFRANCE, Engineer-in-Charge, Ames Aeronautical Laboratory, Moffett Field, Calif.

TECHNICAL COMMITTEES

AERODYNAMICS AIRCRAFT STRUCTURESPOWER PLANTS FOR AIRCRAFT AIRCRAFT ACCIDENTSAIRCRAFT MATERIALS INVENTIONS AND DESIGNS

Coordination of Research Needs of Military and Civil Aviation

Preparatio_ of Research Programs

Allocation of Problems

Prevention of Duplication

Consideration of Inventions

LANGLEY MEMORIAL AERONAUTICAL LABORATORY AMES AERONAUTICAL LABORATORY

LANGLEY FIELD, VA. MOFFETT FIELD, CALIF.

Conduct, under unified control, for all agencies, of scientific research on the fundamental problems of flight.

OFFICE OF AERONAUTICAL INTELLIGENCE

WASHINGTON. D. C.

Collection, classification, compilation, and dissemination ofscientific and technical information on aeronautics

II

REPORT No. 723

WIND-TUNNEL INVESTIGATION OF NACA 23012, 23021, AND 23030 AIRFOILS

EQUIPPED WITH 40-PERCENT-CHORD DOUBLE SLOTTED FLAPS

By THOMAS A. HARRIS _nd ISADORE G. t_ECANT

SUMMARY 40-percent-chord single-slotted flap on the same air-

An" investigation was conducted in the NACA 7- by foils are reported in references 3, 4, and 5. The Fowler

lO-foot wind tunnel to determine the effect of the deflection and the venetian-blind flaps have also been investigatedof main and auxiliary slotted flaps on the aerodynamic oil the 12-percent-thick airfoil, and the results are re-section characteristics of large-chord NACA 23012, 23021, ported in references 1 and 6. Data are presented in

and 23030 airfoils equipped with/_O-percent-chord double reference 7 for split flaps of various chord on 12-, 21-,slotted flaps. The complete aerodynamic section charac- and 30-percent-thick airfoils. The results of tests of ateristics and envelope polar curves are given for each airfoil- 25-percent-chord double-slotted flap on the 12-percentflap combination. The effect of airfoil-thickness is shown, thick airfoil are reported in reference 8.

and comparisons are made of single slotted flaps with The data presented in reference 8 indicated that thedouble slotted flaps on each of the aizJoils, double slotted flap was superior to the single slotted

The maximum section lift coefficient of an airfoil with flap for high lift and for low drag at the high sectiona 40-percent-chord double slotted flap was found to increase lift coefficients. In tlle present report are given the

slowly with increasing thickness, reaching a value of 3.7 results of the tests of the NACA 23012, 23021, andfor the 30-percent-thick airfoil. For any airfoil thickness, 23030 airfoils, each equipped with a 40-percent-chordthe double slotted flap gave a higher value of section maxi- double slotted flap.

mum llft coefficient than either the _O-percent-chord or the MODELS_5.66-percent-chord single slotted flaps. The large lift PLAIN AIRFOILS

,_oefficients for the double slotted flaps were accompanied Three basic models, or plain airfoils, were used in5y large pitching-moment coefficients. The section profile- these tests; each had a chord of 3 feet and a span of 7_rag coefficient of an airfoil with a double slotted flap in- feet. The models were constructed of laminated wood

_reased with an increase in thickness at all except very and were built to the NACA 23012, 23021, and 23030_igh lift coefficients. For a given airfoil thickness, the profiles. The thickness of each of these airfoils is,touble and the single slotted flaps gave about the same sec- respectively, ]2, 21, and 30 percent of the airfoil chord._ion profile-drag coefficients for section lift coefficients less The airfoil ordinates are given in table I. These air-

_han 2.0; above this value the double slotted flap gave the foils had previously been used for the split-flap investi-:ower section profile-drag coefficients, gation reported in reference 7.

INTRODUCTION SLOTTED FLAPS

The National Advisory Committee for Aeronautics Slot shapes.--The slot shapes used were the same asms undertaken an extensive investigation of various those used for the single slotted flaps reported in refer-firfoil-flap combinations to furnish information applic- ences 1 to 5. The piece forming the slot shape for the

_ble to the aerodynamic design of high-lift devices for main slotted flap was attached directly to the mainreproving the safety and the performallce of airplanes, portion of the airfoil; for the auxiliary flap the slotk high-lift device capable of producing high lift with shape was formed by cutting the trailing edge of therariable drag for landing and high lift with low drag m_in flap. The slot shapes for the three airfoils areor take-off and initial climb is believed to be desirable, shown in figure 1.)ther desirable aerodynamic features are no increase Flaps.--The flap contours were the same as those used

n drag with the flap neutral; small change ill pitching in the investigation of the single slotted flaps reported

nomellt with flap deflection; low forces required to in references 1 to 5. The main flap was hinged to the,perate the flap; and freedom from possible hazard due main portion of the airfoil by special fittings, and theo icing, auxiliary flap was hinged to the main flap. The flap

The results of an investigation of a 25-percent-chord shapes are shown in figure 1 and the flap ordinates arcingle-slotted flap on airfoils of 12-, 21-, alld 30-percent given in table II. The deflection of the main flap ishickness are reported in references 1 to 3; results of a measured between the flap chord and the chord of the

1

2 REPORT NO. 723--lNTATIONAL ADVISORY COMMITTEE FOI_ AERONAUTICS

main airfoil; whereas, for the auxiliary flap the deflec- were the same airfoils used in the investigation of theLion is measured between its chord and tile chord of the split flaps reported in reference 7. Tests were made,main flap. however, to determine the effects of the breaks in the

The models were made to a tolerance of d_0.015 inch. surface of the airfoil with the flaps undeflected.TESTS Because of the large number of tests involved in

The models were mounted vertically in the closed test determining the optimum paths for the main and theauxiliary flaps on each airfoil, iL was assumed that thesection of the NACA 7- by 10-fool wind tunnel so as

to span the jet completely except for small clearances opLimum paths for the single slotted flaps (referencesat each end. (See references 1 and 9.) The main air- 1 to 5) would be the optimum paths for the combina-foil was rigidly attached to the balance frame by torque Lion. Tests were therefore made for each position ,.

and deflection of the main flap as previously determined.Lips .O0/c /hick For each position and deflection of the main flap, the

® F/oz nose po/nts auxiliary flap was tested at its previously determined- -- ----C---- -

_ -- 7/Sc---_H_"-_"SZZOc 1 optimum positions and deflections. For each airfoil,

Chord/,_,e "__ flap combination, the flaps were deflected through aQ -.......... __ sufficient range to obtain the maximum lift coefficient.:047b0

_' :vet--" .... 4----?-m-+.40c_ An angle-of-attack range from --6 ° to the angle of.70¢ .4_:_ aLtack for maximum lift was covered in 2 ° increments"'-;808/0

for each test. Lift, drag, and pitching moment were(a) NACA 23012 airfoil with double slotted flap. measured at each angle of attack.

° 1-_ _ .ozzC I L/p-_J l RESULTS AND DISCUSSION

5a3.',,_ |

dimensional coefficient form corrected for tunnel-wall

7(-5- -i . _.8033c effect and turbulence as explained in reference 1.-.59/c

(b) NACA 23021 airfoil with double slotted flap.c_ section lift coefficient (I/gc)

G"

=7750 1 ....i -:860 c% section profile-drag coefficient/ - _lL,psl (do/qC)

"' " section pitching-moment coefficient__ Chord/ine :0__C _ c_,_: _-)0 about aerodynamic center of plain air-

/el __1R_!°65c ...... section effective maximum lift_ 60,0 _ -. qOc _ C lerna z

(c) NACA 23030 airfoil with double slotted flap.

FIGUI_E 1.--Sections of NACA 23012, 23021, and 23030 airfoils with 40 percent-chord f [Cm( .... )0]e,..._

doubleslotted flaps, coefficient _ c_m_q- _ -]tubes, wttich extended through the upper and the lower whereboundaries of the tunnel. The angle of attack of themodel was set from outside the tunnel by rotating the l section lift

torque tubes with a calibrated electric drive. Approxi- do section profile dragmately two-dimensional flow is obtained with this Lypeof installation and the aerodynamic section character- m( .... )0 section pitching momenListics of the model under test can be determined.

q dynamic pressure (1/2pV 2)A dynamic pressure of 16.37 pounds per square fool

was maintained for all the tests, which corresponds to a c chord of basic airfoil with flapfullyvelocity of about 80 miles per hour under standard at- retracLed

mospheric conditions and to an average test Reynolds cz_ section maximum lift coefficientnumber of about 2,190,000. Because of the turbulence

in the wind tunnel, the effective Reynolds number R, [cm(.... )0]¢t_ section pitching-moment coefficient atwas approximaLely 3,500,000. (See reference 10.) For maximum lift coefficienLall tests, R, is based on the chord of the airfoil wilt1 theflap retracted and on a Lurbulenee factor of 1:6 for the It disLance from aerodynamic center oftunnel, airfoil to center of pressure of tail,

No tests were made of the plain airfoils because they expressed in airfoil chords

NACA 23012, 23021, AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPS 3

and given in figures 2, 3, and 4. Because these da,ta have

a0 angle of attack for infinite aspect ratio already been discussed in reference 7, no further com-ment is believed necessary.

all main flap deflection Effect of breaks in surface.--The effect on the sectionprofile-drag coefficient of the breaks in the airfoil NUt-

as2 auxiliary flap deflection faces at the slot entries and exits when the flaps are re-

PRECISION tracted is shown in figure 5. In these tests the slotswere sealed so that there was no air flow through them.

The accuracy of the various measurements in the The breaks in the surface of the NACA 23012 airfoiltests is believed to be within the following limits: cause an increase in the section profile-drag coefficient

a0.............. ±0. 1° _:0. 0006 from 0.003 to 0.004 throughout the lift range. Forc%(°_=I'°)....... the NACA 23021 iairfoil , the' increment of the section

ct_a_ ............ %0. 03 c%(_z=2.5)....... :t:0. 002

Cm(a,c,)0........... ±0. 003 ah and as2........ _:0. 2°± 0. 0003 Flap position_ ± 0. 001C

C dOm in ..................

•044The data from the tests with the main and the aux-

iliary flaps retracted and undeflected have been cor- _ •040rected both for the effect of breaks in the surface at the _-

.q)•_ .036

_J

.048 _ .032

.044 ._ .028i

c?.o4o .oe

._ .036 ._o• "020Ut

.o3_ ¢om 16

.0/

_ .020 _ .004 o

¢.o/0 _ _o<--_ o_•_._ "_

.0/2 .s< 0 .,2 , .4 :6 .8 /.0. 1.2 "4_ Sec/,'bni,Wcoerrioi_n/,q

_ .008 FIGURE 3. Aerodynamic section characteristics of NACA 23021 plain airfoil.0

,_oo4._ profile-drag coefficient is 0.0055 at a section lift coef-

_ 0 ficient of 0, increases to 0.0072 at c_=0.75, and then(_ decreases to 0.0048 at c_=1.2. For tim NACA 23030_ 0 .Z .4 .8 .8 1.0 1.2 1.4 1.8 airfoil, the increment of the section profile-drag eo-

,Fecfiooliftcoeff, cie,'v/;cz efficient decreases from about 0.012 at low section liftFIaUaE2.--AerodynamicsectioncharacteristicsofNACA23012plainairfoil, coefficients to about 0.008 at cz=0.8. With properly

designed doors and flaps to close the breaks in the lowerslot entries and exits and for the effect of the flap hinges, surface of the airfoils, all or most of the drag incrementNo such corrections were applied when the flaps were may be eliminateddeflected because of the large number of tests required, Airfoils with double slotted flaps.--The aerodynamicbut it is believed that the relative merits of the various section characteristics of the airfoils tested with 40-

arrangements are inappreciably affected, percent double slotted flaps are presented in figures 6to 10 for the NACA 23012 airfoil, in figures 11 to 15

AERODYNAMICSECTIONCHARACTERISTICS for the NACA 23021 airfoil, and infigures 16 to 20 for

Plain airfoils.--The complete aerodynamic section the NACA 23030 airfoil. These figures show the effectcharacteristics of the three basic airfoils tested are of variation of auxiliary flap deflection az_ for a given

4 REPORT NO. 723--NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

main flap deflection aI1. As has been previously pointed flap deflection and the airfoil thickness. Any deflectionout, a complete investigation of all the combinations of the auxiliary flap, in general, increases the slope ofof flap deflection and position for the main and the the lift curve over that of the plain airfoil. This effectauxiliary flaps on each airfoil would require a prohibitive is apparently a function of airfoil thickness, the increasenumber of tests. It was therefore decided to move in slope being about 5 percent, 13 percent, and 60 per-

and to deflect the main and the auxiliary flaps of each cent for the NACA 23012, 23021, and 23030 airfoils,airfoil along the optimum paths determined in previous respectively. (See figs. 6, 11, and 16.) It may betests of each flap as a single slotted flap. The follow- noted, however, that the slopes of the lift curves for the

three airfoils with the auxiliary flaps deflected are aboutthe same. Deflection of the main flaps for all but the

.o48 30-percent-thick airfoil tends to decrease the lift-curve

.o.¢4 slope although the slope still remains higher than forthe plain airfoils.

_.o4o At a given section lift coefficient and main flap dc-_-" flection, the negative pitching-moment coefficient in--_ .o26 creases with auxiliary flap deflection for all the airfoils.

The section pitching-moment coefficient also increases.o22 rapidly with main flap deflection. The change in slopeo

#. o_8 of the pitching-moment curves for large flap deflectionsmay be undesirable. It should be noted, however, that

--_ the destablizing effect at these large flap deflections and"_ .024

high lift coefficients is not very pronounced for flap de-.o2o fleetions below the optimum for maximum lift coeffi-

cients, except for the 30-percent-thick airfoil.,_ .o/6 Polar envelope curves for each main flap deflection,

obtained from figures 6 to 20, are plotted in figures 21,• 012

-k.

.008 .020I

_, .004 o .016

k .... AioiJ_ 0 _ .r o NACA 27012

_ _ <I.012'_'-=--- _'---- o ,, 230_?0

',,3 u Sec/,'on I/f/ coeff,@/ezT/, C, _" "_0_..008

FIGI)'RE 4.--Aerodynamic section characteristics of NACA 23030 plain airfoil. _ O) _ _ _.

ing table gives the source from which each flap path _ c_oo4 _(9(D _ ------= _._

was obtained. _ -- I

Flap Flap designation iiz reference ence 0 .2 .4 . C .8 /. 0 /.2 /. 4

NACA l_efer- ,_,ec//bn //ff coeff/cJen/, czairfoil

:FIGURE 5.--Increment of section profile-drag coefficient due to breaks in the surfaces

If Main ......... I 0.40c flap 1-b ................. ] 4 I of the airfoils at the slot entrances and exits for the NACA 230 series with 0.40c23012 ..... z _Auxiliary .......... 0.2566c flap 2=ll ........... 1 I double slotted flaps. Stl--_f_--_0.

flV[ain- ............ I 0.40c flap 1-b ............... __..I 523021..... : [Auxiliary ............ 0.2566c ilap 2-b ............. 2

)'Main ............. 0.40c flap 1-b ...... 3

23030 ..... I Aux iary ......... 0.2566cflap 1-b .... 3 22, and 23 for the NACA 23012, 23021, and 23030 air-foils, respectively. These polars show the lowest sec-

The path of the auxiliary flap on the NACA 23012 tion profile-drag coefficient obtainable at a given see-airfoil is the optimum indicated by reference 1 only for tion lift coefficient for a constant main flap deflection.a main flap deflection of 0°. For other values of as_, In the case of the NACA 23012 airfoil (fig. 21) it isthe auxiliary flap was moved along a path as close to shown that, for section lift coefficients less than 1.2, thethe optimum as the hinge fittings permitted. This plain airfoil gives the lowest section profile-drag eoeffi-procedure was necessitated by the fact that the fittings cients. At higher section lift coefficients, a main flaphad been altered after the single slotted flap had been deflection of 30° gives the lowest section profile-dragtested. In any case, the actual paths followed by the coefficient. In reference 4 it is pointed out that theflaps are shown on the figures, drag for %_=30 ° at az_----0° is erratic, and it is believed

Inspection of figures 6 to 20 shows that deflection of that the values of ce0 over the lift range from c_=1.4 toeither auxiliary or main flaps affects the slopes of the cz=1.9 should be disregarded. The 30° deflection islift curves to some degree, which is determined by the optimum for maximum section lift coefficient.


0S

4

_- 2.2 o------o----o.__ -o-----o-o-ca

•-_ _ ______, ,

8 -.4

&.,_

Q--.8 --

tJ -( __

-,-/.o -- _._ ,_.__ _ _

•36 v --.._

.3'2

z_ m v 40 I5-0836 5.50 4.00 2.50 /.50 0.50 -----

y_ 3.3/i3.75 3.753.25 2.25 /.75

._ .24

.20 i

i

.08 °"_"__ _

/_ .ICao

/6

-8-.4 0 ,4 .8 /.2 /.6 2.0 2.4 2.8 _2 3.C

._ec/ion //fl coef_/c/en_, cz

FIGURE7.--Aerodynamic section characteristics of I"qAOA23012airfoil with 40-percent-chord do_zbleslotted flap. ah= 10°;x_=5.50;Yl= 5.50. Xl, Yl, Xeqy= are given in percentairfoil chord.


.._

•_ o __

.._5_.-._

-,.o =:-_,.. ' -

t-"'_ / /.3Z -. "

.28 v

¢0 A r-, J

._., 50 ,I ?

-- 8..36 5.5X 4.00 2.50 /.,GO 0.50 _/ I

i_ _1_ 3..91 3.7_ 3.753.252.25 1.75 /

ql

_ ._0 "

_..iz / _ .i./U

__._.--.._

0

16

.J'2 7i

-O-.4 0 .4 .8 ,{2 1.6 2.0 _4 _.8 3.Z ' 3.6

Section I/ft coefficient, ct

F[OUF*E&--Aerodynamic section characteristics of NAOA 23012airfoil with 40-percent-chord double slotted flap. all=20°; x1_--3.50;yi=5.50; xi, y,, x_,Yl are given in percentairfoil chord_

404439--41--2

8 REPORT NO. 723--NATIONAL ADVISORY COMMITTEE :FOR AERONAUTICS

O

4

-.2.2b

j

_ -.6 a, a ______,_ ---a-_i

•_- ,_

•_o . Y'-k.

_-I. 0 -- -- % -.

.3_ \-_:_

.32 ----

\

• 28I o I n. I u I v 0

rYs, deg 0 I0 20 JO 40

"4 -- -- - "x_ 8.36 5.50 4.00t250 ] 1.50Ya 3.9/ 3.75 ,.3.75 3.25 2._25

.2

.tJ

.20 ,

f

¢..Is . /

itj

.o8 .7

.04 _._ .

0

/6

-8-.4 0 .4 .8 LZ A6 2.0 2.4 ,:£._ff 3,.2 3.6"

Section lift coe£fic/ent, c_

FIGURE 9.--Aerodynamic section characteristics of N__OA 23012 airfoil with 40-percent-chord double slotted flap. _/1=30°; xl= 1.50; Y1=3.50. xi, Yu x2, y_ are given m percentairfoil chord.

0

/G

tj

b4_

-8-.4 0 .4 .8 1.2 AS 2.0 2.4 2.8 3. 2 3._

See//'on Eft coefF/c/e_/, c z

FIGURE 10.--Aerodynamic section characteristics of NACA 23012 airfoil with 40-percent-chord double slotted flap. _1;_=40°;xl=--0.50; y1=1.50, xl, yl, x2, y2 are given in per-cent airfoil chord.

10 _EPORT NO. 723--NATIONAL ADVISORY COMMITTEE FOI_ AERONAUTICS

_"-2 _ "---__i.--___

<>

_-.4 _....-_="_ =_=_ _,_ _=:_. _=::_ _z:_=_:_

(3

_-.6&

_-.8 --

_-/.o _? x,.36

•32 i

.28

o

o A 0 _ O"

_'.z4 "_ ._,_Io I_o12o13o14o2olgo•_ "_% 8,33 5,0013.50 0,50 0.00 0.00 O.EO,_J

V_ 4.85 6.0015.00 3.00 2.50 2.50 2.00

.zo

t

_ .16 f

u

?/

.08 _i--> _j_--c, -'-'_'_ _

0

_ /_/ // /'/

-8-.4 0 ,z_ .8 I. 2 I,_ 2,0 2.4 2.8 3. 2 3.6

Sec//on I/"ff coeff/cienf, c z

F[QU_ ll.--Aerodynamie sectioncharacteristicsof NAO_ 23021airfoil with 40-percent-chorddoubleslotted flap. _. =0°; x_=iI.50;//_=9.20, x_, th,x_,Y_aregiven in percentairfoil chord.


"_ -.2 _ o--__ _x____ ______

_ -.4 ....... ___ ____

o

_-I.0

..36

.32

Q 0 Z_ [] _7 0 I_. V

',2,

.20

•/G ...._rK"e.

_ _._ ,_. .._r--_ _

°lU.00 _.1

•04 _ _ n'-1-m'1

0

"$ s _/'_/ J" - Y_--

,_, _ _.J_ ,__-8

-.4 0 .4 .8 L2 I.G 2.0 2.4 2.8 3.2 3.6Secl/'on 1/f/ coeff/c/enf, cz

FI_U_E_2._Aer_dynami_se_ti_nchara_t_ristics_fNA_A23_2_airf_i_with4_-per_nt-_h_rdd_ubles_tted_ap. _s=10°;xl:8.50;yl=9.50. xi, y_,x2,y_are given in percentairfoil chord.

0

/6

"$ 8

0

-8-.4 0 .4 .8 /.2 1.6 2.0 2.4 2.8 3.2 ,3.6

,Sed.f/on //ff coeff/cl'ent, cz

FIOURE 14.--Aerodynamic section characteristics of NACA 23021 airfoil with 40-percent-chord double slotted flap. _i1=30 °. x_, Yl, x_, y_ are given in percent airfoil chord.

14 REPORT NO. 723--NATIONAL ADVISORY COMMITTEE :FOR AERONAUTICS

Gs

"*.2_ -.2.._tl

u -.4 o ) -_'e_ o

o

_-/.0 -

• ,36

.32 .,7> _ --

..8

"¢ o ,', [] v I 0 " /o _f_,de; o I/o I zo 13o 14o /.u y,_ 14.85 6.00 5.00,3.00 Z.50 I

u. 20 /

L

_ ,.I..,, I_

"_ .,'2 ¢ _ _'' :_"-t_QI

• 08

./c.e

/ /

N o a" __-8

-:.4 0 .4 .8 12 L6 2.0 2.4 2.8 3.2 3.6

Section /if/ coefficient, c l

F[GUR_ 15.--Aerodynamic section characteristics of NACA 23021 airfoil with 40-percent-chord double slotted flap. &.l=40°; x_=l.50; yi=4.50, x_, y_, x_, y_ are given in percentairfoil chord.


o

"6 _ .._. <_._

-.4 0 .4 .8 Z_ L6 2.0 _4 2.8 3.B - 3.65ec}/on //f_ coeffic/eof, Cz

FIGURE16.--Aerodynamic section characteristics of NAGA 23030airfoil with 40-percent-chord double slotted flap. a_.1=0°;xl = I7.53;yj= 14.85. xl, yl, x2,y_are given in percentairfoil chord.

404439--41----3


0

¢ -_..

.32

.28 T

ca

.z4 o,Xt}

0 I10 eo ao 40 50 |_,_ .'_ ,deg_f_x o I _ I o I v I "O I _.CO -- -- //.66/0.50 5.50 1.500.50 -GSO

.__ u_ a.9o /o.0o/o.ooa.oo z.oo 4.oo I

° J_ o _0

.08 _ _"--'_ ""-"- P/

c___._..___ _-_!

c_

,,._ t..-o_j J _._

J / ''z_'1 _ __

-8-.4 . 0 .4 .8 Z2 AS 2.0 2.4 3.2 ,3.6

Secl/on lifl coefficTen/, c z

FIgurE 17.--Aerodynamic section clmracteristics of NA CA 23030airfoil with 40-percent-chord double slotted fl_p. _. = :[0°; x_= 14.50;y_= 15.00. x_, yz,x_, y_are g_ven in percentairfoil chord.

NACA 23012, 23021, AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPs ]7

0

._ "-o_.

QJ

'o-/.o__ <--_, --_-----_ _-.._"-"_

.j_-- __- -p _

•32 -- ' i

._'_. _4 o zx o v 0 r." 6s_,de9 o /o 2o 30 14Ol5O

x_ II6G /0.50 5.50 1.50 0.50 -0.50y_ 9.sozo.oozo.ooaoo zoo4.00 _j

.20 r

. /,

/6

/ 2.

-8=4 0 .4 .8 l_ 1.6 2.0 Z.4 Z.8 3Z 3.8

_Cecf/on /if/ coeff/cienf, c z

FIGU_E18___-er_dynamicsecti_n_h_ra_ter_stics_fN&_A23_3_jrf_I_with4_-percent-_h_rdd_ub]es_tted_p_ ._=20°;x_=10-50;/h=l&00. xby_,x_,//_regivenJnpercent_ir foil chord.


o 0

Q9

_ -.4

,_ -.O

" l%

u _

cO-/. o _-

.3s- ..%....____ _.. ->'J

Y E_ \-.¢, "x>',,-

.28 . - _ 1

/ls6 la5Ol5.5o1.50 0.50 r _:eo y, ,9.,90 I0.0010.00 8.00 ZOO / f /

r

.16 /

_) c_ "_''°/

08

.O4

0

/6

° j"_ oI a " l u-_ /

-.4 0 .4 .8 L2 L6 2.0 2.4 2.8 3.2 3.6Section liff coefflcient, c t

FIeuRs 20.--Aerodynamic section characteristics of NAOA 23030 airfoil with 40-percent-chord double slotted flap. _rl=40°; x1=4.50; Yl =9.00. xl, yl, x_, y2 are given in pereenl;airfoil chord.


0 I O- o iI0 ....... _ I I0 A !

20 I | 20 m I.32 30 .... i 1-- ,30 v

40 -- -- - I 40 0I

20 i 60 v I

.......

¢ Ii

° / iG .24

_ JI __

= / ,'_.eoi ! /+_ / L I"

/ ,' /.16 ._Y" i

k -'I , //

•- . / ,_ {_'

-I ,SY•08

I?:4 0 .4 .0 /.2 L6 2.0 2.4 2.6 _2 3.6 4.0

_ection coe£Ficien_, c t

FIGURE21. Envelope polar curves for NACA 23012airfoil with 40 percent-chord double slotted flap.

NACA 23012, 23021, AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPS 2_

I&/_,deg ,deg0 0 o -- , i/0 ....... I0 ,,

20 20 o ii

30 30 v _J4o 40 <> I

L;50 _. I60 _, I I

/¢ I '

I /

/ $

' ] ,c.o -- " i/

,/Q _ I1¢ #

.Iz _ -I"I -''_ '

__

........ ___°

0=4 0 .4 .8 /.-.? /6" 2.0 _.4 2.8 3,2 8.6 4.0

5eclion //f/ coeflricient, ct

FIGURE22.--Ezivclope polar clzrves for NACA 23021airfoil with 4_perce_t-cllord double slotted flap.


I I

611,deg &]'z ,deg ,t.40 0 -- O o

/O ....... /O _ ',20 . 20 []30 30 v

4o-__- ,oo II.36 50 _.60 _"

I Ii

.32 ,I_ /

r° /

C, 1 /"

', /',/ ;

/

b ,,

.12 .....-'"-""" " - '

2 "s" J

•08 _ _ ""-" "_ _-_i_

.............. _22_222_-_-

o-4 0 .4 .8 1.2 L6 E.O E.4 2.8 3.? 3.6 4.0

._ecl/on�if/coefficientcz

FIGURE23.--EnvelopepolarcurvesforNACA 23030airfoilwith40-percent-chorddoubleslottedflap.


.44 I zec/ion IA/r'fo// d_. ,deg

.40 230/2 0 o ',23030 I0 " ',23021 20 o

30 v

I ,,oo i.36IIIII

/,.s2 lI

¢ ;t,l

f'I ,

b L

I j"

_ .20 't_

.o

' /./2 ";f_i S

0-=4 0 .4 .8 /.2 1.6 2.0 2.4 2.0 3.2 3.6

,_ec//o,'_ /iftcoefficient, c z

FmURE 24.--Comparison of 40-percent-chord double slotted flap on NACA 23012, 23021, and 23030 airfoils.


The polar envelopes for the NACA 23021 airfoil (fig. in figure 24. These envelopes show the minimum sec-22) show that the plain wing gives the lowest value of tion profile-drag coefficient that may be obtained withsection profle-drag coefficient for section lift coeffi- the three airfoils at any section lift coefficient. As haseientsless than 1.0. From cz=l.0 to about cz---2.4, the been previously noted, tile profile-drag data for the

lowest section profile-drag coefficient is given by a NACA 23012 airfoil with _ii==30 ° and _i2=0 ° were er-main flap deflection of 0°; whereas, for section lift ratic; the values of cd0 over the lift range of c_=1.4 tocoefficients above 2.4, the minimum section profile- cz=].9 have been disregarded in drawing the envelopedrag coefficient is given by _s_=20 °. The section maxi- of the envelopes. The section profile-drag coefficient

mum lift coefficient is given by _f1=30 °. increases with the airfoil thickness throughout the liftAs in the case of the other two airfoils, the plain range except above a section lift coefficient of about 3.2,

NACA 23030 airfoil (fig. 23) gives the lowest section where the 30-percent thick airfoil gives a lower sectionprofile-drag coefficient at low section lift coefficients, profile-drag coefficient than the others.From c_=0.5 to ct=l.9, the section minimum profile- Effect of thickness on maximum lift.--The effect ofdrag coefficients are obtained with a main flap deflec- _he auxiliary flap deflection on the increment of sectiontion of 0°. In the lift range of 1.9 to 3.2, a 20 ° main maximum lift coefficient with various main flap deflee-flap deflection is required for optimum section profile- tions is shown in figure 25 for the three airfoils. Thedrag conditions, while a main flap deflection of 309 increment of the section maximum lift increases notgives the lowest section profile-drag coefficients at only with the auxiliary and the main flap deflectionssection lift coefficients above 3.2. Maximum section but also with the airfoil thickness. The maximum

lift is obtained with _I_=40 °. increment of section maximum lift coefficient ACzma_is obtained with the NACA 23012 and 23030 airfoils

COMPARISON OF AIRFOILS OF DIFFERENT THICKNESS WITH

DOUBLESLOTTEDFLAPS "_vhen _r2:=40°; the NACA 23021 airfoil gives the maxi-

Effect of thickness on profile drag.mEnvelopes of mum Ac_..... when _r2--30 °.tile envelope polar curves of figures 21 to 23 are given The effect of tile main flap deflection on the increment

2.8

i

_J'l ,deq __

2. 4 0 ---------o20----------_

.- ,o----. C/F-__q

0

_--/.6 _ _ /

// (a) (b) (c)

0 20 40 60 0 _ 40 60 0 20 40 60Awxi/iQry fl_p deflect/on, 6re ,deg

(a) NACA 23012 airfoi]. (b) NACA 23021 airfoil (e) NACA 23030 airfoil.

FIOUR_ 25.--Effect of auxiliary flap deflection on the increment of section nmximum lift coefficient for the various airfoils.

NACA 23012, 23021, AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPS _o

of section maximum lift coefficient is shown in figure 26. expected. It is of interest to note that similar results

The highest Act..... for the NACA 23012 and 23021 have been obtained with split flaps (reference 7) andairfoils was given by a main flap deflection of 30 ° and, single slotted flaps (reference 3).for the NACA 23030 airfoil, by a deflection of 40 °. COMPARISONOF VARIOUSSLOTTEDFLAPS ON EACHAIRFOIL

The maximum increments increase with airfoil thick- '_ v.'_om-ar:sons of a 25.66-percent slotted l.vfla'_, 40a

ness, and this effect becomes more marked as _fl is v v_-_'_ercent.slott.eAflan, and a 40-percent double slotted flanincreased. The rapid increase in the increment of tilesection maximum lift coefficient with airfoil thickness

3.2 , ,

Airfoil 6_ ,de_7 _______----- ------ -------_ec¢/on v 30

-- 23012 -- 0 40--- 23021 _, 50.... 23030 i;," 60

_8

/

I

i

, _-._-._.t /

...... ;7"

/

Flapo_ ,'VaneZ_l 0.25660 s/oiledo-------- .40c s/olted I

.40c double s/aired1

0 /0 20 30 40

Main flap deflection, 6f_,deg

FIGURE 26.--Effect of main flap deflection on increment of section maximum lift

coefficient of NAO2k 230 airfoils with 40-percent-chord double slotted flaps. I12 /6 20 24 28

is not readily apparent in the final section maximum Airfoil /hickness, percent c

lift coefficient, which (as can be seen from fig. 27) is not F_u._ 27.--Effectofairfoilthicknesson sectio .... i...... liftcoefficientofNACA230 airfoils with and without slotted flaps,

greatly affected by thickness; and, whereas values ofAc4n_,; increase about 40 percent with an increase in on the NACA 23012, 23021, and 23030 Mr/oils areairfoil thickness from 12 to 30 percent, the section presented in figures 28, 29, and 30, regpectively. Atmaximum lift coefficient increases by only about 7 section lift coefficients below about 2.0, the doublepercent over the same thickness range. In view of the slotted flaps have about the same section profile-dragfact, however, that the section maximum lift coefficient coefficients as the single slotted flaps for all threeof the plain airfoils decreases 30 percent with the airfoils. For the higher section lift coefficients, theincrease in thickness, the small magnitude of the double slotted flaps give less section drag titan theincrease in maximum lift for the flapped airfoils is single slotted flaps.


oO _ ' II

i

_. _ "'---o__1-_-_ __..__-.4 _" -'- "-- _

Gb_ ;,o

-i..

q--.8

tJ

u_ #-/o/9 Re f'.-I.00.256Co 2-5 /

•40o /-b 4.32 .40e double s/of/ed

6/ ,deg (_?a On double _/o//ed I"/ot9)

o o l.28 I0

20 _30 v

40 o " Iso _ ', J

60 _-- ¢ C---I

I.20 ....

_ ' /"_ ./6i

/Q II

0

U _

_ z

.os /4,;; "/

.04 _-I-"

0"=4 0 .4 .6 1.2 L6 2.0 2.4 2.8 3.Z 3.6

Section /if/" coefficient, Ct

FIGURE 28,--Coinparison of slotted flaps on NACA 23012 airfoil.


0

¢J

-.4

(3 ....._-.6 "'.

g_--.8Qo

U

½ -/. O

•3Z F/op Re £.0.2565c 2-b 2 --

.40c /-b 5 4.4_0cdouble s/otted --t

.28 5/ ,deg (SZz on doub/e 2/ofted f/czp) -- ]

l

0 o Ii

I0 A ,

' i20 _ l30 v &40 o I50 t,

u .BO

/8

_ ,

ok.12

.0

_ .o_ --

.o4 _:_:_

I i i r t t i i , i

0 =4 0 .4 .8 Z2 15 2.0 2.4 $8 3.2 3.6Secl_/on //f# coeff/c/en_, c I

FIGURE 29.--Comparison of slotted flaps oil NACA 23021 airfoil.


0

-.2

_ "_. \

_ _ ,

cl-'8 4

-I.O "r

Flap Re £.•32 02566c I-b 3

.40c I-b 3

.40c double _loffed

.Z8 &y ,deq (Z$iz on double s/o/fed flop) - _ ------_0 o I

/30 _7

_" 40 <>._. 50 _ _ I.u 60 _, _ / _--

_o _ /(3 ..

0 •

_ ./2 "

//; /

•08 ' .//

/ I "40°

<_,,.oo_+ 2oo -3o°W+4Lo ' ' ' _ _ _ ' '>P"-.4 0 .4 .8 L2 L6 2. 0 2.4 z.i8 3.2 3.6

Sec]/on /lfl' coeff/c/e[71, c z

lq'[GURE30.--Comparisonof slotted flaps on i'¢ACA 23030_irfoil.

NACA 23012, 23021, AND 23030 AIRFOILS WITI-I DOUBLE SLOTTED FLAPS 29

On the basis of the maximum obtainable section lift 3.G

coefficient, the double slotted flaps show a considerablegain over the single slotted flaps on the airfoils (fig. 27) ...........On the NACA 23012 airfoil, _the increase in section 32--'---- .-""maximum lift coefficient over that of the plain airfoil ,"

//

is 81 percent, 87 percent, and 123 percent for the _2.825.66-percent slotted flap, the 40-percent slotted flap, _ _ -- ....and the 40-percent double slotted flap, respectively. _-" _-'_---2--_

In the case of the NACA 23021 airfoil, the respective :_2.4increases are 107 percent, 110 percent, and 162 percent.; %

O3.6"

_2.O

.... 1 ............

-" _I.G..'" _ ......... .40c double slotted flop

-- -- -- .40c slotted flopj2.8 -_==-- -- ..... _ .25G6"c slotted f/dp

SSI-- l ,2 --2.4

_ .8,

._ 2.o"_ .41

/.6......... .40c double slotted flop

.40c slotted flap 0 I 2 3 4 5 6"-- .26 TGc slotted flop F_']l length, It

5_0 /'_ FIGURE 32.--Section effective maximum lift coefficients for slotted flaps on NACA

_. 23021 airfoil.

.8 3.6 ..... !! .-_

.4 az-- , ---_ --//

z.e-- ---[7-.....0 / 2 .2 4 5" 6' _-

Toil length, It _ __ / !__FIGURE 31.---Section effective maximum lift coefficients for slotted flaps on NACA _) / _ _ _ "

23012airfoil, _ 2-4'----V- / /'

while the increases for the NACA 23030 airfoil are 160 _ --_ -- _-- --percent, 182 percent,and 260 percent. _z.o .......V

Although the section maximum lift coefficients _s [obtained with the double slotted flaps are greater than ._ _________ double 5/ottec /

flop)the coefficients obtained with either of the single " /.6 -_ .40c slotted flv;p J -- -

slotted flaps regardless of airfoil thickness, it must be _ __[ -----.zsGec s/ot/e_d_opl

remembered that the pitching-moment coefficients are _ _1 --

_oalsogreater. Thus, a double-slotted-flap installation _ /.e i 7

will require a greater negative tail load to balance the _ __ __ _ .__

pitching moment than will a single-slotted-flap instal- _ .... l_

lation, and it therefore appears desirable to take the _"8_/i _ ____|__ !--I

tail load into consideration when the maximum lift _ .... _-----coefficients are compared. Accordingly, section effec- 41 _______ ___tire maximum lift coefficients were computed for each

formula--airf°il-flaPcombination for [vari°usl tail lengths by the I I iLem( .... )OJC,ma x 0 / Z 3 d 5 S

C_emax = Cl mar Jr I t Taft lena/h, &

These data are presented in figures 31, 32, and 33. For FIGURE33.--Sectioneffectivemaximumlift coefficientsforslottedflaps on NAOA23030 airfoil_


each of the airfoils, the effective maximum lift coeffi- REFERENCES

cient obtained with the double slotted flap is greater 1. Wenzinger, Carl J., and Harris, Thom_as A.: Wind-Tunnelthan the coefficient obtained with either of the single Investigation of an N. A. C. A. 23012 Airfoil with Various

slotted flaps. The superiority of the double slotted Arrangements of Slotted Flaps. Rep. No. 664, NACA,

flaps in this respect increases with tail length. 1939.The pitching-moment coefficients plotted in figures 2. Wenzinger, Carl J. and Harris, Thomas A.: Wind-Tunnel

28 to 30 are those obtained when the flaps are moved Investigation of an N. A. C. A. 23021 Airfoil with Variousand deflected to the positions that give minimum Arrangements of Slotted Flaps. Rep. No. 677, NACA,

values of section profile-drag coefficient at a given 1939.

section lift coefficient. The difference in pitching- 3. Recant, I. G.: Wind-Tunnel Investigation of an N. A. C. A.23030 Airfoil with Various Arrangements of Slotted Flaps.moment coefficients of the various slotted flaps is mostT. N. No. 755, NACA, 1940.

marked for the NACA 23012 airfoil. On that airfoilthe 25.66-percent-chord single slotted flap gives the 4. Harris, Thomas A.: Wind-Tunnel Investigation of an N. A.

C. A. 23012 Airfoil with Two Arrangements of a Wide-lowest values of pitching-moment coefficient while the Chord Slotted Flap. T.N. No. 715, NACA, 1939.

double slotted flap gives the highest values throughout 5. Duschik, Frank: Wind-Tunnel Investigation of an N. A.the lift range. On the NACA 23021 airfoil the lowest C.A. 23021 Airfoil with Two Arrangements of a 40-Per-values of pitching-moment coefficient are given by the cent-Chord Slotted Flap. T. N. No. 728, NACA, 1939.

40-percent-chord single slotted flap while the 25.66- 6. Wenzinger, Carl J., and Harris, Thomas A.: Preliminary

percent single slotted flap and the double slotted flap Wind-Tunnel Investigation of an N. A. C. A. 23012give about the same pitching-mom6nt coefficients below Airfoil with Various Arrangements of Venetian-Blindcz=l.2. In the case of the NACA 23030 airfoil there Ftaps. Rep. No. 689, NACA, 1940.is little difference in the pitching-moment coefficients 7. Wenzinger, Carl J., and Harris, Thorn.as A.: Wind-Tunnelgiven by the three flaps for lift coefficients up to 1.6. Investigation of N. A. C. A. 23012, 23021, and 23030 Air-

foils with Various Sizes of Split Flap. Rep. No. 668,

For lift coefficients less than 1.6, the 40-percent single NACA, 1939.slotted flap gave the lowest pitching-moment coefficientswhile, at higher lift coefficients, the 25.66-percent single 8. Wenzinger, Carl J., and Gauvain, William E.: Wind-TunnelInvestigation of an N. A. C. A. 23012 Airfoil with a Slotted

slotted flap gives the lowest value of pitching-moment Flap and Three Types of Auxiliary Flap. Rep. No. 679,coefficient. NACA, 1939.

CONCLUDING REMARKS 9. Harris, Thomas A.: The 7 by 10 Foot Wind Tunnel of the

National Advisory Committee for Aeronautics. Rep.The effect of increasing the airfoil thickness on the No. 412, NACA, 1931.

aerodynamic characteristics of airfoils with double 10. Jacobs, Eastman N., and Sherman, Albert: Airfoil Section

slotted flaps was to increase the section profile drag Characteristics as Affected by Variations of the Reynolds

through most of the lift range although, at very high Number. Rep. No. 586, NACA, 1937.section lift coefficients, the section profile drag wasreduced by an increasing thickness. The section maxi- TABLE I

mmn lift coefficient increased slowly with increasing ORDINATES FOR NACA 230 AIRFOILSairfoil thickness.

For a given airfoil thickness, tim section profile drag [stationsandordinatesin percent ofairfoilchord[of the 40-percent-chord single slotted flap, the 25.66: NACA 23012 NACA 23021 NACA 23030

percent-chord single slotted flap, and the 40-percent- Stationchord double slotted flaps was about the same at sec- Upper L .... Upper %...... Upper L....surface surface surface surface sur fac6 surface

tion lift coefficients less than 2.0. For higher section liftcoefficients, the double slotted flap gave the lowest 0 ....... 0 __ _ 0 4.82 0

1.25 2. 67 --1.23 4. 87 --2. 08 7. 37 --2. 63

section profile-drag coefficient regardless of airfoil 2._ 3.61 -1.71 6.14 -3.14 8.90 -4.275 4.91 --2. 26 7. 93 --4. 52 11.05 --6. 54

thickness. The section maximum lift coefficients ef 75 5.80 -2.6l 9.13 -555 12.57 -8.2810 6 43 -2 92 1003 -6. 32 13.68 -9. 65tile airfoils with double slotted flaps were considerably 15 7.19 -3. 50 11.19 -7. 51 15. 20 -11.5220 7. 50 --3.97 11.80 ' --8. 30 16. 07 --12. 61

higher than those of the airfoils with single slotted 25 760 -4.28 12.05 -8.76 _16.46 --13.2030 7.55 --4.46 12.06 --8.95 16.57 --13.46

flaps for all airfoil thicknesses. The large lift coeffi- 40 7.14 -4.48 11.49 -8.83 15.89 =13.1350 6. 41 --4.17 10. 40 --8. 14 14. 38 --12.11

cients for the double slotted flaps were accompanied by 60 5.47 -3. 67 8.90 -7.07 12.34 -10.4770 4. 36 --3.00 7. 09 --5. 72 9. 86 --8. 42

large pitchh_g-moment coefficients. 80 3.08 -2.16 5.05 -4.13 7.03 -6. 0990 1.68 --1.23 2.76 --2.30 3.87 --3.4095 .92 --.70 1.53 --1.30 2.15 --1.86

1O0 .13 --. 13 .22 --. 22 .32 --. 32

LANGLEY MEMORIAL AERONAUTICAL LABORATORY, L.E. radius 1.58 4.85 9.90

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS,Slope of radius through end of chord: 0.305

LANGLEY FIELD, VA., August 6, 1940.

O9

_:_Z

Positive directions of axes and angles (forces and moments) are shown by arrows

Axis Momen_'about axis Angle Velocities

Force(parallel . Linear

Designation Sym-bol tOsymbolaXis)Designation Sym- Positive 'Designa- i Sym - (tempo- Angularbol direction tion bol nent alongaxis)

Longitudinal ..... X X Rolling ..... L Y------_Z Roll ..... _ u pLateral .......... Y Y Pitching .... M Z------_X Pitch .... 0 v qNormal ..... _..... Z Z Yawing .... N X------_Y Yaw ..... _ w r

Absolute coefficients of moment Angle of set of control surface (relative to neutral

c_L M N position), _. (Indicate surface by proper subscript.)

(rolling) (pitching) (yawing)

4. PROPELLER SYMBOLS

D, Diameter pp, Geometric pitch P, Power, absolute coefficient Cp--pn3D 5

_ _I-pv_p/D, Pitch ratio G_, Speed-power coellicient--_/_n 2V', Inflow velocityV_, Slipstream velocity v, Efficiency

T n, Revolutions per second, r.p.s.

T, Thrust, absolute coefficient CT--.pn2D 4 _, Effective helix angle tan-_lz_ V _\'z _rrn/

Q, Torque, absolute coefficient CQ_-_n_2D5

5. NUMERICAL RELATIONS

1 hp.--76.04 kg-m/s--550 ft-lb./sec. 1 1b.=0.4536 kg.1 metric horsepower=l.0132 hp. 1 kg--2_2046 lb.1 m.p.h.--0.4470 m.p.s. 1 mi.--1,609.35 m--5,280 ft.1 m.p.s.--2.2369 m.p.h. 1 m--3.2808 ft.

Documents

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS · national advisory committee for aeronautics report no. 723 wind-tunnel investigation of naca 23012, 23021 and 23030 airfoils equipped