Wind-tunnel investigation of NACA 23012, 23021, and 23030 airfoils equipped with 40-percent-chord double slotted flaps

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 ISIDOR E G. RECANT / RE P RODU C ED BY NATIONAL TECHNICAL INFORMATION SERVICE U.S DEPA R I M ENI O f CO MM ERCE SPRIN G FIELD. VA 221 61 AERONAUTIC SYMBOLS 1. FUNDAMENTAL AND DERIVED UNITS Me tric English Unit Abbrevi a - Abbrevi a - * " tion Unit tion Length ...... l meter .................. m foot (or mile) ........... • Symb o l ft (or mi) T i me ........ t se c ond ............... s se c ond (or hour) ...... _ c (or hr) F orce ........ F weight of 1 k i logram ...... k g weight of 1 p ound ...... _ P o wer ....... P h o rsepow (metric) ............... h o rsepower ........... hp f kilome_e r per hour ...... kph miles per hour ......... mph Speed_ V [meters pe second ........ mps feet per second ....... fps 2 . GENERAL S Y M B O LS W Weight--: mg v Kinem a tic viscosity g Stand a rd a ccelera*tion of gr a vity--9.80665 m / s _ p Density (mass per unit volume) or 32.1740 ft / sec 2 Stand a rd density of dry a ir, 0.12497 kg-m-_-s 2 a t 15 ° C m Mass - W and 760 mm; or 0.002378 lb-ft- 4 sec _ g Specific weight of "st a ndard" a ir , 1.2255 kg / m _ or 1 Moment of incrti a -- mk _. (Indic a te axis of 0.076511b / cuft radius of gyr a tion k by proper subscript.)

Coefficient of viscosity 3. AER O DYNA MI C S Y M BOL S S Area i _ Angle o f setting of wings (rel a tive to thrust line) S _ Are a of wing i t Angle of st a bilizer setting (rel a tive to thrust G G a p line) b Sp a n Q Result a nt moment c Chord _ Result a nt a ngul a r velocity b 2 V1 A Aspect r a tio , _ R Reynolds number , p _- where 1 is a linear dimen- V True a ir speed sion (e.g. , for an airfoil of !.0 ft chord , 100 mph , 1 _ z 2 standard pressure at.15 ° C , the corresponding q D y namic pressure , _ p t Reynolds number is 935 , 400; or for an airfoil of 1.0 m chord , 100 mps , the corresponding

_z

Z a bsolute coefficient Lift , C L= q N Re y nol d s number is 6 , 865 , 000) D Drag , a bsolut e coefficient C D_ - D a A ngle o f a ttack q _ Angle of downwash D o Profile drag , absolute coefficient c Do_ D ° a o Angle of attack , infinite aspect ratio q _ a _ Angle of attack , induced D _ a _ Angle of att a ck , absolute (measured f rom zero- D _ Induced drag , absolute coefficient CD _-- qS lift position) D v Parasite drag , absolute coefficient C D_ - : D _ _ / Flight-path angle C G Cr o ss-wind forc e , absolute co e fficient c 26 2 6 °

S

REPORT No. 723

WIN D- T U NNEL INVES T I GA TI ON O F NACA 23 01 2 , 23 0 21

AND 23030 AIRFOILS EQUIPPED WITH

40-PERCENT-CHORD DOUBLE SLOTTED FLAPS

By T H O M A S A. HARR IS an d IS ID O R E G. RECANT Langley Memo r ial Ae r onaut i cal Laborato r y NA T IONAL ADV ISO R Y C O MM IT TE E FO R AER O NA U T I C S HEADQUARTER S , NAVY BUILDI N G , WASHI N GT O N, D. C .

C reated b y act o f C ongress appr o v e d March 3 , 1915 , for t he supervisio n and direction of the scien t ific stud y of the problems of fl i ght (U. S. C ode, Title 50, Sec. 151)• Its membership was increased t o 1 5 by act approved M arch 2, 19 2 9. The members are appoin t ed by the P residen t , and serve as such without compensation.

VANNEVA R BU S H , S e. D., Chairman , RO R E RT E. DOH_ T Y , M . S ., • Washington, D.C. P ittsburgh, Pa.

GEOR G E 3" . MEA D , SC . D ., Vic e Chairman, RO_ E _T H . HIN C KLE Y, A . B. , Wash i ngton, D. C . Ass i s t ant Secretary o f C ommerce• CHA R L E S G . ABBO T , SC . D . , J-ERO_IE C . HUNSAI_:ER , Sc . D . , Secretary, Smithsonian I nstitution• C ambridge, M ass.

HE N RY H . A R N OL D , Major General, United S t a t es A rmy, SYDNEY M . K I_AU S , C ap t ain, United S t a t es Navy, Deputy Chief of Staff, C hie f of the Air C orps, War B ureau of Aeronau ti cs, Navy Dep a rtment.

Depa rt ment. F RA NCIS W . R E I C HE LD E R FER , SO. D., GEORGE H . B R ETT, M ajor G eneral, Uni t ed Sta t es Army, C hief, Uni t ed States Wea t her Bureau° Act i ng Ch i ef of the A i r Corps, War Department. JOHN H. TOWERS, Rear Admiral, Un it ed states Navy, LYMAN J . B R IGGS, Ph. D., Chief, Bureau of Aeronautics, Navy Department.

D i rector, National Bureau of Standards• EDWARD WARNER, SC. D., DONAL D H. C O NNO LL Y, B . S . , Washingt o n, D. C .

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

GEORGE W . L _WIS , Director of Aerona u tica l Research S . PA_ JOHNSTON, Coordinator o f Re s e a rch 5 0HN F. VIC T ORY , S ecretary HENRY J . E . REI D , Engineer -in - C h arge , Langley Memorial Aeronautical Laboratory , Langley Field , Va .

SMI T H J . DEF R AN C E , Engineer - in -C ha r g e, Ames Ae r onautica l Laboratory , Mo ffett Field, Calif .

T ECHNIC A L C O MMITTEES A ERODY N AMIC S A IRC RAF T STRUCTURES POWER PLANT S F O R A_ RCRAFT AIRCRAFT ACCIDENTS A IRCRAFT M A T E RI A L S INVENTI ON S AN D DE S IG N S C oor d i na tio n o f Re s e ar c h N ee ds of Military and Civi l Aviation Preparation of Research Programs Allocation o f Problems Prevention of Duplication Consideration of Inventions L AN G LE Y M E M ORIAL A ERONA U TI C AL L A BORATORY A M ES AERONAUTICAL L ABORAT O RY LA N GLE Y FIELD , V A . M O F F ETT F IELD, CALI F .

Co nduct, under unified c o ntr o l , f o r a ll a g o _ncies, of scien t ific research on the fundamental problems of flight• OFFI C E OF A ERONAUTI C AL INT E LLIGENCE W A SHINGT O N. D. C.

Co llecti o n , classificati o n, c o mpila t i o n, and d isseminati o n of scientific and technical information on aeronau t ics NA T I O NAL ADV ISO R Y C O MMI TT E E FO R AER O NA UTI C S HEADQU A RTER S , NAVY BUILDI N G , W A SHI N GT O N , D. C.

C r ea ted b y a c t o f C ongress appro v ed M ar c h 3, 1915, f o r the supervisio n and di r e ct i o n o f the sc i ent i fic s t ud y of the problems of flight (U. S. Code, Title 50, Sec. 151). Its membership was increased to 1 5 by act approved March 2, 19 2 9. The members are appoin t ed by the P residen t , and serve as such without compensa t ion.

VAN N EV AR B US H , S C. D ., Chairman , RORE_ T E. D O HER T V , M . S., Washington, D.C. P ittsburgh, Pa.

GEORGE J ' . M E / kD , S c. D . , Vice Chairman , ROBER T H . HIN C K LEY , A . B., Washington, D.C. Ass i s t ant Secre t ary of C ommerce.

CHA RL E S G. A B BOT, S c. D . , _ER0_E C. HUN S A KF _I_ , Se . D . , S ecretary, S mithsonian Insti t utio n . Cambr i dge , Mass.

HE NRY H . A R NO L D , Major General, United S tates Army, SYDNE Y M. KRAUS , C aptain, United States Navy, Deput y C hief of Sta ff , Chief of the Air C orps, War B ureau of Aeronaut i cs, :Navy Department.

Depar t ment. Fm_Ncis W . REI C HELDE RF E R , SC . D., GEOR G E H . B R ETT , M ajor General, U nited States Army, Ch i ef, Uni t ed States Weather B ureau.

Acting C hief of the Air Corps, War Department. JOHN H. TOWERS, Rear Adm i ral, United States N avy, L Y MAN J . BR IGGS , P h. D ., C hief , Bureall of Aeron a utics, N av y D e par t m e nt .

D i rector, Nat i onal B ureau of Standards. EDWA R D WARNE R , Se . D . , DONA LD H. CONNO LL Y, B . S. , Washington, D. C .

Administrator of C ivil Aeronau ti cs. O R VI L L E WRIGH T , Se. D., Dayton, Ohio.

G EORGE W . LEWIS, Director of A e rona ut ica l Research S . PA u l. J OHNSTON, Coordinator o F Resear c h J oHn F . V IC T ORY, _ ecretar y HE N RY J. E . RE I D, Engin e er - i _- C h arge , Langle y Me m or ia l Aeronau t ica l Laboratory , Langle y Field, Va .

SMI T H J . DEF RA NCE, Engineer - in - Charge , Ames Ae r onautical L aborator y, Mo ffett F ield, Ca l if .

TE CH N ICA L C O MMITTEES A EROD Y N A MIC S A IRC R AFT STRUCTURES POWER PLANTS F O R AI RCR A FT A IRCRAFT ACC I DENTS A IRCR A FT MA TERI A L S INVENTIO N S A ND DESIG N S Coor d i n atio n o f R es e ar c h Ne e ds of Military an d Civi l A v iatio n Prep a ratio _ o f Research Programs Allocation of Problems P revention of Dup l icatio n Consideration of Invention s L A N G LE Y M E M OR I AL AERONA U TICAL LABORATORY A M ES AERONAUTI C AL LA B ORAT O RY LANGLE Y F IELD , V A . M O F F ETT FIELD , C A LI F .

Cond u ct, unde r uni fi ed control, f o r all a gencies, of scie n tific research o n the fundamental problems of fl i ght.

OFFICE OF AERONAUTICAL INTELLIGEN C E WAS HI N GT O N . D. C.

Collection, classifica t ion, c ompila t ion, and dissemination of scientific and technical information on aeronautics II

REP O RT N o . 7 23

WIND-TUNNEL INVESTIGATION O F NACA 23012, 23021 , AND 23030 AIRFOILS EQUIPPED WITH 40-PERCENT-CHORD DOUBLE SLOTTED FLAPS By THOMAS A . HARRIS _nd ISADORE G . t_ECANT SUMMAR Y 40-percent-chord single-slotted flap o n the same air - An " investigation w as conducted i n 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 investigated of main a n d auxiliary slotted flaps on the aerodynamic oil the 12-percent-thick airfoil , and the resul t s are re- section characteristics o f large - c h ord NACA 23012, 23021, ported in references 1 and 6. Data are presented in and 23030 air f oils equipped with/ _ O -p ercent - 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. T h e results o f tests of a te r istics and envelope polar curves are give n f or each airfoil - 25-percent-chord double-slotted flap on the 12 - percent flap combination . T h e effect o f 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 the double slotted flaps on each of the ai zJ oils , double slotted flap was superior to the single slotted T h e maximum section li ft coefficient of an airfoil with flap for high lift and for low drag at the high section a 4 0 - percent - chord double slotted flap w as f o u nd to increase lift coefficients. In tlle present report are given the s lowly wi th increasing thickness, reaching a value of 3 . 7 results of the tests of the NACA 23012 , 23021 , and for the 30 - percent - thick airfoil . For any ai rf oil t h ickness, 23030 airfoils , each equipped with a 40 - percent-chord the double slotted fla p gave a higher value of section m axi - double slotted flap.

mum llft coe ffi cient than either the _ O -p ercent - chord or the MODELS _ 5 . 66 - p ercent - chord single slotted flaps . The large lift P LAIN AI R FOILS , _ oe ffi cients for the double slotted flaps w ere accompanied Th r ee bas i c mode ls , o r p l ain air f oils , were used in 5 y large pitching - moment coe ffi cients . The section profile - these tests; each had a chord of 3 feet and a span of 7 _r ag coe ffi cient of a n airfoil wi th a double slotted fla p in - feet. The models were constructed of laminated wood _ reased wi t h an increase in thickness at all except very and were built to the NACA 23012 , 23021 , and 23030 _ igh lift coe ffi cients . 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.

_ io n profile - drag coe ffi cients for section lift coe ffi cients less The airfoil ordinates are given in table I. These air- _ h an 2 . 0; above this value t he double slotted fla p gave the foils had previousl y been used for the split-flap investi- : ower section p rofile - d r ag coe ffi cients , gation reported in re f erence 7 .

INTROD U CTION SLOTTED F L A PS The National Advisory Committee for Aeronautics Slot shapes.--The slot shapes used were the same as ms undertaken an extensive investigation of various those used for the single slotted flaps reported in re f er- 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 main reproving the safety and the performallce of airplanes, portion of the airfoil; for the auxiliary flap the slot k high-lift device capable of producing high lift with shape was formed b y cutting the trailing edge of the rariable drag for landing and high lift with low drag m_in flap. The slot shapes for the three airfoils are or take-off and initial climb is believed to be desirable, shown in figure 1.

)ther desirable aerodynamic features are no increase F laps.--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 , a nd the o icing, auxiliar y flap was hinged to the main flap. The flap The results of an investigation of a 2 5-percent-chord shapes are shown in figure 1 and t he flap ordinates arc ingle-slotted flap on airfoils of 12- , 21- , alld 30-percent given in table II. The deflection of the main flap is hickness are reported in re f erences 1 to 3; results of a measured between the flap chord and the chord of the 2 REPORT NO. 723--lNTATIONAL A D VISORY COMMITTEE FOI_ AERONAUTICS main airfoil; whereas , for the auxiliary flap the deflec- were the same airfoils used in the investigation of the Lion 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 the

auxiliary flaps on each airfoil , iL was assumed that the

section 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 (references at 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.

Li ps . O0/c /hick For each position and deflection of the main flap , the

® F/oz n o s e po / n t s auxiliary flap was tested at its previously determined

- -- ----C---- - _ -- 7/S c ---_H_"-_" SZZO c 1 optimum posit i on s and deflections. For each airfoil,

Cho r d/ ,_,e "__ flap combination , the flaps were deflected through a

Q - .......... __ suffi c ient range to obtain the maximum lift coefficient.

:04 7 b0

_' : vet --" .... 4----?-m-+. 40c _ An angle-of-attack range from --6 ° to the angle of

.7 0 ¢ .4_:_ aLta c k 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 ea c h angle of attack.

° 1

-_ _ . o zz C I L/ p-_J l RE S UL TS A N D D IS CU S S I ON

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/ g c )

G"

= 775 0 1 .... i -: 86 0 c % section profile-drag coefficient

/ - _lL,psl ( d o /qC )

" ' " section pitching-moment coefficient

__ Chord/in e : 0 __C _ c _,_: _ - )0 about aerodynamic center of plain air-

/ e l __1R_! °65 c ...... section effective maximum lift

_ 60 , 0 _ -. q O c _ C lerna z (c) NACA 23030 airfoil with double slotted flap.

FIGUI_E 1. --Sections of NA C A 2 301 2 , 23 0 21 , a n d 2 3 03 0 airfoi l s with 40 perce n t- c hord f [ Cm ( .... ) 0 ]e, . . . _

doubleslotted flaps, coefficient _ c _m_q- _ - ]

tubes , wttich extended through the upper and the lower where

boundaries of the tunnel. The angle of attack of the

model was set from outside the tunnel by rotating the l section lift

torque tubes with a calibrated electric drive. Approxi- d o section profile drag

mately two-dimensional flow is obtained with this Lype

of installation and the aerodynamic section character- m ( .... )0 section pitching momenL

istics of the model under test can be determined.

q dynamic pressure (1 / 2 pV 2)

A dynamic pressure of 16.3 7 pounds per square fool

was maintained for all the tests , which corresponds to a c chord of basic airfoil with flapfully

velocity of about 80 miles per hour under standard at- retracLed

mospheric conditions and to an average test Reynolds c z_ section maximum lift coefficient

number of about 2, 190 , 000. Because of the turbulence

in the wind tunnel , the effective Reynolds number R , [ c m( .... )0]¢t_ section pitching-moment coefficient at

was approximaLely 3 , 500 , 000. (See reference 10.) For maximum lift coeffi c ienL

all tests , R , is based on the chord of the airfoil wilt1 the

flap retracted and on a Lurbulenee factor of 1:6 for the I t disLance from aerodynamic center of tunnel, 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

a 0 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 section

profile-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-

PREC IS I ON tracted is shown in figure 5. In these te s ts the slots

were sealed so that there was no air flow through them.

The accurac y of the various measurements in the The breaks in the surface of the NAC A 2301 2 airfoil tests is believed to be within the following limits: cause an increase in the section profile-drag coefficient

a 0 .............. ±0. 1° _:0. 0006 from 0.003 to 0.004 throughout the lift range. For

c %(°_=I'°)....... the NACA 23021 iairfoil , the' increment of the section

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

C m(a,c,) 0........... ±0. 003 a h and as2 ........ _:0. 2°

± 0. 0003 Flap position_ ± 0. 001 C

C dO m in ..................

• 0 4 4

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

iliary flaps retracted and undeflected have been cor- _ •0 4 0

rected both for the effect of breaks in the surface at the _-

.q) •_ . 036 _J . 048 _ . 03 2 . 044 ._ . 0 2 8 i

c?.o4 o .oe

._ .036 . _o • "020 U

t

.o3 _ ¢o m 1 6

. 0/

o

_ . 020 _ .004

¢. o/0 _ _ o < - -_ o _

•_._ "_

. 0/ 2 . s< 0 . , 2 , . 4 :6 . 8 /. 0. 1 .2 " 4

_ Se c /,' b ni, W coe rri o i _n /, q

_ . 008 FIGURE 3. A e rodynamic section characteristics of NACA 23021 plain airfoil.

,_ 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- ,F ecfioo l if t coeff, cie, ' v/ ; c z efficient decreases from about 0.012 at low section lift FIaUaE 2.--Aerodynamic section characteristics ofNACA23012 plainairfoil , coefficients to about 0.008 at c z=0.8. With properly

designed doors and flaps to close the breaks in the lower

slot entries and exits and for the effect of the flap hinges, surface of the airfoils , all or most of the drag increment

No such corrections were applied when the flaps were may be eliminated

deflected because of the large number of tests required , Airfoils with double slotted flaps.--The aerodynamic but 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 6

to 10 for the NACA 2 3012 airfoil , in figures 11 to 15

AER OD Y N A M IC S E CT ION C H ARAC T ERI S T I CS for the NACA 23021 airfoil , and in figures 16 t o 20 for P lain airfoils.--The complete aerodynamic section the NACA 23030 airfoil. These figures show the effect characteristics of the three basic airfoils tested are of variation of auxiliary flap deflection az_ for a given

4 REPORT NO. 723--NATIONA L ADVISORY COMMITTEE FOR AERONAUTICS

main flap deflection aI1. As has been previously pointed flap deflection and the airfoil thickness. Any deflection out , a complete investigation of all the combinations of the auxiliary flap , in general , increases the slope of of flap deflection and position for the main and the the lift curve over that of the plain airfoil. This effect auxiliary flaps on each airfoil would require a prohibitive is apparently a function of airfoil thickness , the increase number 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 2 3012, 2 30 2 1 , and 23030 airfoils , airfoil along the optimum paths determined in previous respectively. (See figs. 6 , 11 , and 16.) It may be tests 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 about

the 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 for

the plain airfoils.

_ .o4o At a given section lift coefficient and main flap dc-

_- " flection , the negative pitching-moment coefficient in-

-_ . o 26 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 slope o

#. o _8 of the pitching-moment curves for large flap deflections

may 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 . 020 I _, . 004 o . 01 6

k .... Ai o iJ

_ 0 _ . r o NACA 2 7 012 _ _ <I .012 '_'-=--- _'---- o ,, 230 _? 0 ',,3 u S ec/, ' on I/f/ coeff,@ /e zT/ , C , _" "_ 0_.. 00 8 FIGI)'RE 4 . --Ae ro dy n amic section chara c teristics of NACA 2 30 3 0 plain airfo i l . _ O) _ _ _.

ing table gives the source from which each flap path _ c_ oo4 _

( 9 (D _ ------= _._

was obtained. _ -- I

NACA l_efer- ,_ ,ec// b n //ff coeff/cJen/ , c z airfoil :FIGURE 5.--Increment of section profile-drag coefficient due to breaks in the surfaces Flap Flap designation iiz reference ence 0 . 2 . 4 . C . 8 / . 0 / .2 / . 4 If Main ......... I 0.40 c flap 1-b ................. ] 4 I of the airfoils at the slot entrances and exits for the NACA 230 series with 0.40 c 2301 2 ..... z _Auxiliary .......... 0.2566 c flap 2=ll ........... 1 I double slotted flaps. S t l--_f_--_0.

f lV[ain- ............ I 0.40c flap 1-b ............... __..I 5 23030 ..... I Aux iary ......... 0.2566 c flap 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 is the auxiliary flap was moved along a path as close to shown that , for section lift coefficients less than 1.2, the the 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 flap had been altered after the single slotted flap had been deflection of 30 ° gives the lowest section profile-drag tested. In any case , the actual paths followed by the coefficient. In reference 4 it is pointed out that the flaps 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 c e0 over the lift range from c _=1.4 to either auxiliary or main flaps affects the slopes of the c z=1.9 should be disregarded. The 30 ° deflection is lift curves to some degree , which is determined by the optimum for maximum section lift coefficient.

6 RE P ORT NO. 723--NATIONAL A D V ISORY COMMITTEE FOR AERONAUTICS

S _- 2 . 2 o------ o ----o.__ -o-----o-o-ca •-_ _ _____ _, ,

8 -.4

&

.,_

Q--. 8 -- tJ -( __

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

•3 6 v --. . _ . 3 '2 z _ m v 40 I5- 0 83 6 5 . 50 4 . 00 2. 50 / . 50 0 . 5 0 ----- y _ 3 . 3/ i 3 . 75 3 . 753 .2 5 2.2 5 / .7 5 ._ . 24 .2 0 i i . 08 °"_"__ _ / _ . IC ao /6 - 8 -. 4 0 , 4 .8 / .2 / . 6 2. 0 2. 4 2. 8 _2 3.C . _ e c /i o n //f l coef _ /c/en _, c z FIGURE7 . --Ae r odynamic section cha r a c ter i stics o f I" q AOA2301 2 airfo i l with 4 0-percent-chord do_zbleslotted flap. a h = 10 ° ; x _= 5 .50; Y l = 5 .50. X l, Y l , X eq y = are given in percent airfoil chord.

NACA 23012 , 23021 , AND 23030 AIRFOILS WIT H DOUBLE SLOTTED FLAPS 7 .._ • _ o __ .._ _.-._

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

t -

" ' _ / / . 3 Z -. " .2 8 v ¢ 0 A r-, J . _ . , 50 ,I ?

i_ _ 1 _ 3 ..9 1 3 .7_ 3 .7 53 .2 5 2. 25 1 . 75 / ql _ ._ 0 " -- 8 .. 36 5.5X 4.00 2.5 0 / ., GO 0. 5 0 _ / I

_.. i z / _ .i ./

U __._.--.._

.J ' 2 7 i

- O -. 4 0 . 4 . 8 , { 2 1 . 6 2. 0 _ 4 _. 8 3 .Z ' 3 . 6 Sec tion I/ft coefficien t , ct F[OUF*E &--Aer od yna mi c sect i o n cha r acteristics of NAOA 23012airfoil with 40-percent-chord double slotted flap. a l l=2 0° ; x 1_--3.50; y i=5.50; x i, y ,, x _ ,Y l are given in percent airfoil chord_ 404439--41--2 8 REPORT NO. 723--NATIONAL ADVISORY COMMITTEE :FOR AERONAUTICS O -.2

.2

b

j

_ -. 6 a, a ______, _ -- - a -_ i

•_- ,_

•_o . Y ' - k .

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

.3_ \-_ : _

.32 ---- \ • 28 I o I n . I u I v 0 r Ys , deg 0 I0 20 JO 40 "4 -- -- - "x _ 8 . 36 5 . 50 4 . 00 t 2 50 ] 1 . 50 Ya 3 .9 / 3.75 ,. 3 .7 5 3 . 25 2. _ 25

.2

.tJ .2 0 ,

f

¢ .. Is . /

itj

. o 8 . 7

. 04 _._ .

/6 - 8 - .4 0 . 4 . 8 LZ A6 2 . 0 2. 4 , :£ ._ff 3, .2 3.6 " Se c tion lift c o e £fi c /ent, c_ FIGURE 9.--Aerodynamic section characteristics of N_ _OA 2301 2 airfoil with 40-percent-chord double slotted flap. _ / 1=30°; x l= 1.50; Y 1=3.50. x i, Y u x 2, y _ are given m percent airfoil chord.

/G t j b 4_ - 8 -. 4 0 . 4 . 8 1 . 2 A S 2 . 0 2 . 4 2 . 8 3. 2 3 ._ See// ' on E f t coefF/c/e _ / , c z FI G URE 10.--Aerodynamic section characteristics of NACA 23012 airfoil with 40-percent-chord double slotted flap. _1 ; _=40°; x l=--0.50; y 1=1.50, x l , y l , x 2 , y 2 are given in per- cent airfoil chord.

10 _EPORT NO. 7 2 3--NATIONAL ADVISORY COMMITTEE FOI_ AERONAUTICS

_ " -2 _ " ---_ _

i . -- _ __ <> _-. 4 _ . . .. -_="_ =_=_ _,_ _=:_. _=::_ _ z :_=_:_ (3 _-. 6

&

_-. 8 -- _- / . o _? x , . 36

.28

o • 32 i o A 0 _ O"

_'.z4 "_ ._ , _I o I_o12o 13o 14o 2o l go

•_ "_% 8 , 33 5, 0 01 3.50 0 , 50 0 . 00 0.00 O . EO , _J V _ 4.85 6 . 0 01 5 . 0 0 3 . 00 2. 50 2. 50 2.00

. zo

t _ . 16 f u /

?

. 08 _i--> _j_--

c , -'-'_'_ _

_ / _ / // / ' /

- 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[ Q U_ ll.--Aerodynamie section characteristics o f N AO_ 230 2 1 airfoil with 40-percent-chorddoubleslotted flap. _. =0°; x _=iI.50; // _=9 . 20, x _ ,th, x_ ,Y _ aregiven in percent airfoil chord.

NACA 23012, 23021 , AND 23030 AIRFOILS WIT H DOUBLE SLOTTED FLAPS 11

"_ -.2 _ o--__ _ x ____ ______

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

o _- I . 0 .. 36 . 3 2 Q 0 Z_ [] _7 0 I_ . V ', 2, . 20 • / G . . .._ r K "e.

_ _._ , _. .._r-- _ _ l U

°

. 00 _.1 • 04 _ _ n'-1-m'1

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

,_, _ _ . J_ ,__

- 8 -. 4 0 . 4 . 8 L 2 I.G 2 .0 2.4 2 . 8 3 .2 3 . 6 Secl/ ' on 1/f/ coeff/c/enf, cz FI_U_E_2._Aer_dynami_se_ti_nchara_t_ristics_fNA_ A2 3_2_airf_i_with4_-per_nt-_h_rdd_ubles_tted_ap. _s=10°; x l:8 . 50; y l=9.50. x i, y _, x 2 ,y _are giv e n in percent airfoil chord.

/6

" $ 8

- 8 -. 4 0 .4 .8 /.2 1 .6 2 . 0 2 . 4 2 . 8 3 . 2 , 3 . 6 , Se d .f/ o n //ff coeff/ c l'e nt , c z F I O U RE 14.--Aerody n amic section ch a racteristics of NACA 2302 1 airfoil with 40-pe r cent-chord do u ble slotted fl ap. _i1=30 °. x _, Y l, x _, y _ are given in pe r cent airfoil c h ord.

14 RE P ORT N O. 7 2 3--NATIONAL A D V ISORY C OMM I TT EE :FOR A E RONA U T I CS

G

s

"*. 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 z o 1 3o 1 4o

/

.u y, _ 1 4 . 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 Se ctio n / if / c oe ffi c i e nt, c l F[GU R _ 15.--Aerodynamic section characteristics of N ACA 23021 airfoil with 40 - percent-chord double s l otted flap. &.l = 40° ; x _ = l.50; y i = 4.50, x _ , y _, x _, y _ are given in percent airfoil chord.

N ACA 2301 2, 2 3021, AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPS 15 o "6 _ .. _ . < _ . _ -. 4 0 . 4 . 8 Z _ L6 2 . 0 _ 4 2. 8 3 . B - 3 . 6 5ec} /on //f _ c oeff i c/eof, Cz FI G UR E 16 . --Aerodynamic section cha r acte r istics of NA G A 23030 ai r fo i l w i th 4 0 -pe r cen t -chord double slotted flap. a_. 1=0°; x l = I7. 5 3; y j = 14.85 . x l , y l, x 2, y _are g i ven in percent airfoil chord.

404439--41----3

16 REPORT NO . 7 2 3--NATIONAL ADVISORY COMMITTEE FOR A ERONAUTICS

¢ -_..

. 32

. 28 T

c a

.z4 o,X

t}

0 I 10 e o a o 4 0 5 0 |

_,_ .'_ , de g _f_ x o I _ I o I v I "O I _ .CO -- -- // . 66/0 . 50 5 . 50 1.5 0 0 . 50 - GSO

._ _ u _ a .9 o / o . 0o/o.ooa.oo z. oo 4 . oo I

° J

_ o _

. 0 8 _ _"- - '_ ""-" - P /

c___._..___ _-_!

c_

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

J / ' ' z_'1 _ _ _ - 8 -.4 . 0 . 4 .8 Z 2 AS 2 . 0 2 .4 3 . 2 , 3 . 6 Secl/ o n lifl c o effic Te n/ , c z FIg u rE 17.--Aerodynamic section clmracteristics of N A C A 23030airfoil with 40-percent-chord double slotted fl_p. _. = :[0°; x _= 14.50; y _= 15.00. x _ , y z ,x _ , y _ are g_ven in percent airfoil chord.

NA C A 23012 , 23021, AND 23030 AIRFOILS W I TH DOUBLE SLOTTED FLAPs ]7 ._ "-o_.

QJ

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

.j_-- __- -

p _ • 32 -- ' i ._'_ . _ 4 o zx o v 0 r.

" 6s_,de9 o /o 2o 30 1 4O l 5O

x_ I I 6 G /0.50 5. 50 1 . 50 0 . 50 - 0 . 50

y_ 9. so z o . oo z o . oo a oo z oo 4. 00 _j

. 20 r .

/ , /6 / 2.

- 8 = 4 0 . 4 .8 l_ 1 . 6 2.0 Z . 4 Z . 8 3Z 3 . 8 _C e c f/on /i f / coeff/cienf , c z FIGU_E18 _ __-er_dynamicsecti_n_h_ra_ter_sti c s_f N &_ A 23_3_jrf_I_with4_-percent-_h_rdd_ub]es_tted_p _ ._=20°; x _=10-50; /h =l&00 . x b y _,x_, // _regivenJnperce n t _i r f o il ch o rd.

NACA 23012 , 2 3021 , AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPS 19 o 0 Q 9

_ -. 4

,_ -. O

%

" l

u _ cO- / . o _-

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

Y E_ \-.¢, "x > ',,-

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/ ls6 la5Ol 5 . 5o 1. 50 0. 50 r _: eo y , , 9 . , 90 I0 . 0010 . 00 8 . 00 Z OO / f / r . 16 / _ ) c_ "_''° / 0 8 . O4 /6

° j

"_ oI a " l u-_ / - .4 0 .4 .8 L 2 L6 2 .0 2 .4 2 .8 3 .2 3.6 Sec ti o n liff coeff lc ient, c t F IeuRs 20 . --Aerodynamic section characteristics of NAOA 23030 airfoil with 40-percent-chord double slotted flap. _ r l=40°; x 1=4.50; Y l =9 . 00 . x l , y l, x _ , y 2 are given in pereenl ; airfoil chord .

20 REPORT NO. 723--NATIONAL ADVISORY COMMITTEE FOR AERONAUTI C S 0 I O- o i I0 ....... _ I I0 A !

2 0 I | 20 m I . 3 2 3 0 .... i 1-- , 3 0 v 40 -- -- - I 40 0

I

2 0 i 60 v I i

¢ I

.......

G .2 4

° / i

_ J I __

= / ,

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i ! /

+_ / L I"

/ ,' /

. 1 6 ._Y" i

k -' I , //

•- . / , _ { _ '

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• 0 8

I

?

: 4 0 . 4 . 0 / . 2 L6 2. 0 2. 4 2 .6 _2 3 . 6 4 .0 _ e c ti on c o e£ Ficien _ , c t FIGURE21. Envelope polar curves for NACA 2 301 2 airfoil with 40 percent-chord double slotted flap.

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

I

& /_ ,de g ,deg 0 0 o -- , i /0 ....... I0 ,, 2 0 20 o ii 30 30 v _J

4o 40 <> I

50 _. I

60 _ , I I

/

¢ I '

I /

L; / $ ' ] , c.

o -- " i/

Q _ I1 ¢ #

, /

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

__

........ ___° = 4 0 .4 . 8 / .- . ? /6 " 2. 0 _. 4 2. 8 3,2 8 .6 4 .0 5e cl ion / /f / coefl r icient, ct FI G U R E 22 .--Ezivclope polar clzrves for N AC A 2 30 2 1 airfoil with 4 _perce_t-cllord d ouble s lotte d flap.

22 REPORT NO. 723--NATIONAL ADVISORY CO M MITTEE FOR AERONAUTICS

I

I

6 1 1, deg &] 'z ,deg , t . 40 0 -- O o /O ....... /O _ ', 2 0 . 2 0 [] 30 30 v . 36 50 _.

60 _ "

4 o -__- ,o o I I

I Ii

_ /

.32 ,I r ° /

C, 1 / "

', /

', / ;

/

b , , . 1 2 .. . . . - '" - "" " " - ' s" J • 08 _ _ ""-" "_ _-_i _

2 "

.............. _ 22 _ 222 _ - _ -

o - 4 0 . 4 . 8 1 .2 L6 E . O E . 4 2. 8 3. ? 3 . 6 4 . 0 . _ e c l /on i f / c oef ficien t c z FIGURE23.--Envelope polar curves for NACA 2 3030 a i rfoil wi t h 4 0-perce n t-chord double slotte d flap.

NACA 23012 , 23021 , AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPS 23

. 44 I ze c/ion I A /r ' fo// d_. ,deg . 40 230/2 0 o ', 2 3030 I0 " ', 230 2 1 20 o 30 v

I ,,oo i . 36

I I I I I

. s 2 l

I ¢ ;

/ , t,l

I ,

f '

b L _ .2 0 't_ .o I j"

' /

. /2 " ;f _ i S -= 4 0 .4 .8 / . 2 1 . 6 2. 0 2 . 4 2 . 0 3 . 2 3 . 6 ,_ ec / /o ,'_ /if tcoefficien t, c z FmURE 24.--Comparison of 40-percent-chord double slotted flap on NACA 2301 2 , 2 3021, and 23030 airfoils.

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

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 with section profle-drag coefficient for section lift coeffi- the three airfoils at any section lift coefficient. As has eientsless than 1.0. From c z=l.0 to about c z---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 c d0 over the lift range of c _=1.4 to coefficients above 2.4 , the minimum section profile- c z=].9 have been disregarded in drawing the envelope drag 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 lift As 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 section profile-drag coefficient at low section lift coefficients, profile-drag coefficient than the others.

From c _=0.5 to c t=l.9 , the section minimum profile- Effect of thickness on maximum lift.--The effect of drag coefficients are obtained with a main flap deflec- _he auxiliary flap deflection on the increment of section tion 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 p r ofile- tions is shown in figure 2 5 for the three airfoils. The drag conditions , while a main flap deflection of 30 9 increment of the section maximum lift increases not gives the lowest section profile-drag coefficients at only with the auxiliary and the main flap deflections section 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 A C zma_

is obtained with the NACA 23012 and 2 3030 airfoils

C O MPARIS O N OF AIR FO IL S OF DIFFERENT THICKNESS W ITH D O UBLE SL O T T E D F L AP S "_vhen _ r 2:=40° ; the NAC A 2 3021 airfoil gives the maxi- E ffect of thickness on profile drag.mEnvelopes of mum A c _ ..... when _r 2 --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 2 . 4 0 ---------o 20 ----- ---- -_

.- ,o ----. C / F-__ q

_J'l , d eq __

_- - / . 6 _ _ /

/

/ (a) (b) (c)

0 2 0 40 60 0 _ 40 60 0 20 40 60 Awxi/iQr y fl _ p de f lect/on , 6re , deg (a) NACA 23012 airfoi]. (b) NA C A 23021 airfoil (e) NACA 23030 airfoil .

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

NACA 23012 , 23021, AND 23030 AIRFOILS WITH DOUBLE SLOTTED FLAPS _ o of section maximum lift coefficient is shown in figure 2 6. expected. It is of interest to note that similar results The highest A c t..... for the NACA 23012 and 230 2 1 have been obtained with split flaps (reference 7) and airfoils 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 °. C OM PAR ISON O F VA R IOUS S L OT TED FL AP S ON EAC H A I R FOI L

40 a

The maximum increments increase with airfoil thick- '_ v . ' _om-ar:sons of a 25.66-percent slotted l. v fla'_ , ness , and this effect becomes more marked as _ f l is v v _-_'_ercent. slott.e A flan , and a 40-percent double slotted flan

increased. The rapid increase in the increment of tile

section maximum lift coefficient with airfoil thickness

3 .2 , , Airfoil 6 _ ,de _7 _______----- ------ ------- _ e c¢ /on v 3 0 -- 23012 -- 0 40 --- 230 2 1 _, 50 .... 23 030 i;," 60 _ 8 / I i , _-._-._.

t /

...... ; 7"

/

Flap o_ , 'V an e Z_l 0 .2 5660 s /oiled o-------- . 40c s/o lt e d I . 40c double s/a i red 0 /0 20 30 40 M a in fl ap deflec t io n, 6f_ , deg FIGURE 26.--Effect of main flap deflection on increment of section maximum lift coefficient of NAO 2 k 2 30 airfoils with 40-percent-chord double slotted flaps. I 12 /6 20 24 28 is not readily apparent in the final section maximum Airfoil /hicknes s , p e rc e nt c lift coefficient, which (as can be seen from fig. 2 7) is not F_u . _ 27.--Effect ofairfoil thickness on sectio .... i...... liftcoefficient ofNACA 230 airfoils with and without slotted flaps,

greatly affected by thickness; and , whereas values of

A c 4n_,; increase about 40 percent with an increase in on the NACA 23012 , 23021 , and 23030 Mr/oils are airfoil thickness from 12 to 30 percent , the section presented in figures 28 , 29 , and 30 , regpectively. At maximum lift coefficient increases by only about 7 section lift coefficients below about 2.0 , the double percent over the same thickness range. In view of the slotted flaps have about the same section profile-drag fact , however , that the section maximum lift coefficient coefficients as the single slotted flaps for all three of the plain airfoils decreases 30 percent with the airfoils. For the higher section lift coefficients , the increase in thickness , the small magnitude of the double slotted flaps give less section drag titan the increase in maximum lift for the flapped airfoils is single slotted flaps.

26 REPORT NO. 723--NATIONAL ADVISORY C OMMITTEE FOR AERON A UTICS

o O _ ' I

I

i

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

_- .4 _" -'- "-- _

G

b_ ;,o - i..

q--.8 tJ u _ # - / o / 9 Re f ' .

- I . 0 0.256 C o 2 - 5 / • 40o / - b 4 . 32 . 40e double s/of/ed 6/ ,d eg (_ ? a On double _ /o//ed I " /ot 9 ) .2 8 I0

o o l

20 _ 30 v

40 o " I

so _ ', J

60 _-- ¢ C ---

I

I

. 20 ....

"_ . /6

_ ' / i

/

Q II U _ _ z

.os /4,;; "

/ . 04 _ - I- " "= 4 0 . 4 .6 1 . 2 L6 2. 0 2. 4 2 . 8 3. Z 3 . 6 S ect ion /if/ " coefficien t , Ct FIGURE 28,--Coinparis o n of slotted flaps on NACA 23012 airfoil.

NACA 23012, 23021 , AND 23030 AIRFOILS WITH DOUB L E SLOTTED FLAPS 27 ¢J -. 4 (3 ....._ -. 6 "'.

g

_--.8 Q o U ½ - / . O • 3 Z F /op Re £ .

0 . 2565 c 2 - b 2 -- . 40c / - b 5 .4_ 0c double s /o tted -- t l . 28 5 / , deg ( S Z z on doub/e 2/ofted f/ c z p) -- ] I 0 o i I0 A , 20 _ l

' i 30 v &

40 o I 50 t , u . BO

/ 8

_ , ok. 1 2 .0 _ . o _ --

. o 4 _ : _ : _

I i i r t t i i , i 0 =4 0 .4 . 8 Z2 15 2 . 0 2.4 $ 8 3 . 2 3 . 6 S e c l _ / o n //f # c o ef f / c/ en _, c I FIGURE 29.--Comparison of slotted flaps oil NACA 2 3 021 airfoil.

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

-.2

_ "_. \

_ _ , cl-'8 4 - I . O "r F lap Re £ .

• 32 0 2 566 c I-b 3 . 40c I - b 3 . 40c d o uble _ lo f fed . Z8 &y , deq ( Z$i z on double s/o/fed flop) - _ ------_ I 0 o

/

3 0 _7

_" 40 <>

. _. 50 _ _ I

.u 60 _, _ / _--

_ o _ /

(3 ..

0 • _ ./ 2 "

//; /

• 08 ' ./

/

/ I " 40°

L

<_ , ,. oo _+ 2 o o -3o°W+ 4

o ' ' ' _ _ _ ' '>P"

-. 4 0 . 4 . 8 L2 L 6 2. 0 2. 4 z .i 8 3 .2 3 . 6 Sec] /on / l fl' coe f f/ c/ e[ 7 1, c z lq'[GURE 30.--Comparisonof slotted flaps on i' ¢ ACA 23030 _irfoil.

NACA 23012 , 2 3021 , AND 23030 AIRFOILS WITI-I DOUBLE SLOTTED FLAPS 2 9

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

coefficient , the double slotted flaps show a considerable

gain over the single s lotted 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 1 2 3 p e rcent for the

_ 2 . 8

25.66-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 :_ 2.4

increases are 107 percent , 110 percent , and 162 percent.; %

O 3 .6"

_ 2 . O

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

-" _ I .G .. ' " _ ......... . 40 c doubl e s l ot te d fl o p -- -- -- . 40 c sl o tt e d flop j2 .8 - _ ==-- -- ..... _ . 25 G6"c sl o tt ed f/dp

SSI-- l , 2 --

2 . 4 _ . 8 ,

._ 2 . o

"_ . 4 1

/ . 6

......... . 40c double s lo tte d flop . 40c slotte d flap 0 I 2 3 4 5 6" -- .2 6 T Gc s lo tt e d flop F_ ']l le ng th , It 5_0 / '_ FIGURE 32.--Section effective maximum lift coefficients for slotted flaps on NACA _. 23021 airfoil.

. 4 a z -- , ---_ --

/ /

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

. 8 3 . 6 ..... !! .-_ T o il leng th , I t _ __ / !__ FIG U RE 31.---Section effective maximum lift coefficients for slotted flaps o n NACA _) / _ _ _ " 23012airfoil, _ 2- 4 '---- V - / / '

while the increases for the NACA 2 3030 airfoil are 160 _ --_ -- _-- --

percent , 182 percent , and 260 percent. _ z . o ....... V

Although the secti o n maxim u m lift c o efficients _ s [

obtained with the double slotted flaps are greater than ._ _________

double 5 /o ttec / fl op )

the coefficients obtained with either of the single "

/ . 6 -_ . 40c s lott ed flv ; p J -- -

_o

also

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

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

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

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

slotted flaps regardless of airfoil thickness , it must be _ __[ -----. zs G ec s / o t/ e_d_ op l

tail load into consideration when the ma x imum lift _ .... _-----

coefficients are compared. Accordingly , section effec- 4 1 _______ ___

tire ma x imum lift coefficients were computed f o r each

lation, and it therefore appears desirable to take the _ " 8 _/i _ ____|__ !--I formula--airf°il-flaP combination for [vari°usl tail lengths by the I I i L em( .... )OJ C,ma x 0 / Z 3 d 5 S C _ emax = C l mar Jr I t T aft len a /h , & These data are presented in figures 31 , 32 , and 33. For FIGURE 33.--Section effective maximum lift coefficients forslotted flaps on NAOA 23030 airfoil_

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

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-Tunnel than 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 Various and 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 most

T. N. No. 755 , NACA , 1940.

marked for the NACA 23012 airfoil. On that airfoil

the 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 230 2 1 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. 2 3012 give about the same pitching-mom6nt coefficients below Airfoil with Various Arrangements of Venetian-Blind c z=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-Tunnel given by the three flaps for lift coefficients up to 1.6. Investigation of N. A. C. A. 2301 2, 23021 , and 2 3030 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 coefficients

while , at higher lift coefficients , the 25.66-percent single 8. Wenzinger , Carl J ., and Gauvain, William E.: W ind-Tunnel Investigation 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, c oefficient. 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 was

reduced by an increasing thickness. The section maxi- TABLE I

mmn lift coefficient increased slowly with increasing ORDINATES F O R NACA 230 AIRFOILS

airfoil thickness.

For a given airfoil thickness , tim section profile drag [stations and ordinates in percent ofairfoil chord [ of the 40-percent-chord single slotted flap , the 25.66: NACA 23012 NACA 230 2 1 N AC A 2 3030

percent-chord single slotted flap , and the 40-percent- Station

chord double slotted flaps was about the same at sec- Upper L .... Upper % ...... Upper L....

surface surface surface sur f ace sur fac6 surface

tion lift coefficients less than 2.0. For higher section lift

coefficients , the double slotted flap gave the lowest 0 ....... 0 __ _ 0 4 .82 0

1.25 2. 67 --1. 2 3 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 -4.27 5 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 12.5 7 -8.28

10 6 43 -2 92 1003 -6. 32 13. 68 -9. 65

tile airfoils with double slotted flaps were considerably 15 7.19 -3. 50 11.19 - 7 . 51 15. 20 -11.52 2 0 7. 50 --3.97 11.8 0 ' --8. 30 16. 07 --12. 61 higher than those of the airfoils with single slotted 25 760 -4. 2 8 1 2 .05 -8.76 _16.46 --13.20 30 7 . 55 --4.46 12.06 --8.95 16.57 --13.46 flaps for all air f oil thicknesses. The large lift c o effi- 40 7.14 -4.48 11. 4 9 -8.83 15.89 =13.13 5 0 6. 41 --4.17 10. 40 --8. 14 14. 38 --12 . 11 cients for the double slotted flaps were accompanied by 60 5.4 7 -3. 67 8.90 -7.07 12. 34 -10.47 70 4 . 36 --3.00 7. 09 --5. 72 9. 86 -- 8. 42

large pitchh_g-moment coefficients. 80 3.08 -2.16 5.05 -4.1 3 7.03 -6. 09

90 1.68 --1.23 2 .76 -- 2 .30 3.87 --3.40 95 .92 --.70 1.53 --1.30 2.15 -- 1.86 1O0 .13 --. 13 . 2 2 --. 22 .3 2 --. 3 2 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 a xes a nd a ngles (forces a nd moments) a re shown by a rrows

Axis Momen_ ' a bout axis Angle Velocities

Force (p a r a llel . Line a r Designation Sym-bol tOsymbolaXis) Designation Sym- P ositive 'Design a - i Sym - (tempo- Angular bol direction tion bol nent along a xis) Longitudinal ..... X X R olling ..... L Y ------_ Z R oll ..... _ u p L a ter a l .......... Y Y Pitching .... M Z ------_ X Pit c h .... 0 v q Normal ..... _..... Z Z Y a wing .... N X ------_ Y Y a w ..... _ w r

A bsolute coefficients o f moment Angle of set of control surface (rel a tive to neutral

c _ L M N position) , _. (Indic a te surface by proper subscript.)

( r olling) (pitching) (y a wing)

4 . PR O P ELLE R SYMBOLS

D, Dia m eter p

p, Geometric pitch P, Power , a bsolute coefficient Cp-- pn 3 D 5

_ _ I -p v _

p/D , Pitch ratio G _, Speed-power coellicient--_ / _ n 2

V', Inflow velocity

V _ , Slipstre a m velocity v , Efficiency

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

T , Thrust , a bsolute coefficient CT --. pn 2 D 4 _ , Effective helix angle tan-_ lz _ V _

\'z _r rn/

Q, Torque , a bsolute coefficient CQ _ -_ n _2 D 5

5. NUMERICAL RELATI O NS 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.