National Advisory for Aeronautics (1944)

8/3/2019 National Advisory for Aeronautics (1944)

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NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

ORIGINALLY ISSUEDOctober 1944 aeAdvance Restricted Report I h J O 5

m-- GATION OF rn ~ A C A 3021 P~IFOILWITH A O.~~-AIRFOIL-CHORD DOUBLE SIXFIZD FIJQ

By Jack Fiechel and John M. Riebe

Langley Manorial Aeronautical LaboratoryLangley Field, Va.

WASHINGTONNACA WARTIME REPORTS are reprints of papers originally issued to provide rapid distribution ofadvance rese arch res ults to an authorized group requiring them f o r the war effort. They were pre -viously held under a security status but are now unclassified. Some of these repor ts were not tech-nically edited. A l l have been reproduced without change in order to expedite genera l distribution.


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NACA RRR NO* L4J05 -ATIONAL ADVISORY COMMITTEE FO R AEROIJAUTICSAEVANCE RESTRICTED REPORT

:*JIXD-TTUNA~ELNVZETIGATION OF A N HACA 23021 AIRFOIL* J ~ I T H 0.32-AIRFOIL-CHORD DOUBLE SLOTTED FLAP

B y Jack Fi s ch el and John M. Riebe

An in ve s t ig a t io n was made i n th e L M L 7- by 10-footwind tunnel o f an ITACA 23021 a i r f o i l w i t h 8 doubles l o t t e d f l a p h aving a chord 32 percen t of t he a i r f o i lchord ( 0 . 3 2 ~ ) o de termine the aerodgi ianic se c t io n charac -t e r i s t i c s w i t h t h e f l a p s d e f l e c t e d a t v a r i o us p o s i t i o n s .The e g f e c t s o f moving the f o r e f l a p and r e a r f l a p a s au n i t a n d o f d e f l e c t i n g or rernoving th e lower l ap of thes l o t w e m also de termined.

Three po s i t i on s were se le c t ed f o r t h e f o r e . f l a p anda t e a ch y o s i t i o n th e maximuii l i f t of t h e a i r f o i l wasobtafned w i t h t h e r e a r f l a p at the naximum deflectLonused a t th a t . fore -f lap pos i t i on . The se c t io n l i f t oft h e a i r f o i l inc reased as the, P o r e f l a p was extended andmaximum l i f t was o bt ai ne d w it h t h e f o r e f l a p d e f l e c t e d 30'i n t he a o s t extended po s it ion.a rilaxI!i~m s e c t i o n l i f t c o e f f i c i e n t of' 3.31, which wash igher than the va lue ob ta ined w i t h e i t h e r a 0 . 2 5 6 6 ~ora 0.li-O~s i ng le -s lo t t ed -f la p arran-ement and 0.25 l e s sd o u b le - s lo t t e d - f l a parrancement on th e same a i r f o i l . The val ues of t h ep ro f i l e -d r a g c o e f f i c i e n t ob ta in ed w i th t h e 0 . 3 2 ~doubleslotted f l a p were l a r g e r t h a n t h os e f o r t h e 0 . 2 5 6 6 ~ o rO.I;OC s i n g l e s l o t t e a f l a p s f o r s e c t i o n l i f t c o e f f i c i e n t sbetween 1.0 and approximately 2.7. A t a l l va lues of t h es e c t i o n l i f t coef f ic ien t above 1 . 0 , t h e 0 . 4 0 ~ oubles l o t t e d f l a p had a l o w e r p ro f i l e d r a g th a n th e 0 . 3 2 ~double s l o t t e d f l a p .s e c t i o n l i f t Coefficient produced by v a r i o u s f l a pd e f l e c t io n s , t h e 0 . 3 2 ~d ou ble s lo t t e d f l a p gave n e g a t iv ethan t h o s e of o th e r s l o t t e d f l a p s 011 the same a i r fo i l .The 0 .32~d ou ble s l o t t e d f l a p gave a 2 p o x im a te ly the samemaximum s e c t i o n l i f t c o e f f i c i e n t a s , b u t h i g h e r p r o f i l e -

This arrangeinent provided

than the va lue ob ta ined w i t h a O.L+OC

A t var ious va lues of the m a x i m u m

h s e c t i o n p i t ching-moment co ef f ic ie n ts t h a t were hi gh er


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2 NACA ARR No. aJ05

APPARATJS AED TESTEModels

An NACA 23021 a i r f o i l wfth a 3 - f o o t chord and a7 - f o o t span was th e b a s i c model xeed i n t h e s e t e s t s .The o r d i n a t e s f o r th e N X A 25021 a i r f o i l s e c t i o n a r eg i v en i n t a bl e I.n a t e d mehogany and tempered wal l board and i s the sameT h e a i r f o f l w a z c o n s t r u c t e d o f lami-

__ ~ ~ _ _ _~ A -

d ra g c o e f f i c l e n t s o v e r t h o entire l i f t range t h an , as i m i l ar arrar -gemect of' a 0.3Cjc dcu'ble slotted f l a p on anNACA 23612 a i r f o i l .TKTHODUCTIOX

The National Adv! s o r y Covmi.ttea f o r Aeronaut ics hasu n de rt ak en en sx t en rj i m i n v es t i g a t i o n of v a r i o u s high-l i f t devices i n o r d e r t o r 'urrdsh i nf 3m .a t i on a9plicab2-et o t h e aerodynamic design of' wirq- f lap coinhinat ions thatw i l l improve the zafetq and peri 'ormarxe o f a i r p l a n e s .F o r use i n t ake-of f anc?. i n i t i a l climb, a h i g h - l i f t d e v i c ecapable of producing h i g h l i f t w i t h lo w drag i s d e s i r a b l e .F o r x s e i n l a n d i n g ? , k\.owsve:ll, h tgh l i f t w ith v a r ia b l ed r ag i s belleved d es i 7 ab l e . Other d e s i r a S l e c h a r a c t e r -i s t i c ? a re : no i n c r e s s e i n Craz wit3 t h e f l a p n e u t r a l ,sm a l l change i n p i t c h h g norwit; with f l a p d e f l ec t 2 0 L i , lowf o r c e s r e q u ir e d t o o g e r a t s t he flap, and frc:sdom f r o mposs ib le hazard due t o icing.

The re s u l t s of var iou s Invest fgatLons on t h eNACA 25021 z 9 r f o i l a r e p re ser it ed i n r e f e r en ces 1, 2, and3 . R e s E l t s f o r the NACA 22021 a i r f o i l . w i th a s i n g l es l o t t e d f l a p h a v i r g a chord 25.66 percefit o f t he a i r f o i lchord ( 0 . 2 5 6 6 ~ ) a r e g i v en i n r e f e r e n c e 1; r e s u l t s for thesame airfoil w i t h a 0 . 4 3 ~ single s l o t t e d f l a p and wi th a0 . 4 0 ~ double s l o t t e d f l a p a r e g iv en i n r e f e r e n ce s 2 and 3 ,r e s p e c t i v e l y .

The p resen t inves t iga t ion , i n which t e s t s were madeof a 0 . 3 2 ~double s l o t t e d f l a p 0x1 t h e N A C A 22021 a i r f o i l( f f g . l), 5 s a c o n t i n u a t i o n o f t h e i n v e s t i g a t i o n r e p o r t edi n r e f e r e n c e 4 of a 0 . 5 0 ~double s l o t t e d f l a p on an WkCA23012 a i r f o i l .


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NACA AFR RO. ~ 4 ~ 0 5 3a i r f o i l previously used f o r t he i n v e s t i g a t i o n s r e p o r t e di n r e f e r e nc e s 1, 2 , and 3 . The t ra i l i ng - edg e se c t io n o fth e model ahead of th e f l a p s was equipped w i t h l i p s ofs t e e l p l a t e r o l l e d t o t h e a f r f o l . 1 c ont ou r and e xt en d in gback t o t h e r e a r flap i n or de r t o pr ov id e t h e b a s i c a i r -f o i l Coilto~W when th e f l a p s w e r e r e t r a c t e d ( f i g . 1).

The double s l o t te d f l a p cons i s ted of a f o r e f l a pand a r e a r f l a p . The f o r e f l ap (0 ,14 67c) , t e s te d was thesame one des ignated fore f l a p B i n t he i n v es t i ga t i onr e p o r t e d i n r e fe r e nc e 4 n6 had an upper surface andt r a i l i n g - e d g e of d ur a l and a lower sur fac e o f laminatedwood. The fo re - f la p p r o f i le i s shown i n f i gu re 1 andi t s o r d i n a t e s a r e g iv en i n t a b l e I . The r e a r f l a p( 0 . 2 5 6 6 ~ ) e s t e d was t h e one u se d i n t h e i n v e s t ig a t io n sr e po r t ed i n r e f e r en c e s 1 and 3 . I t s p r o f l l e i s a l s oshown i n f i gu re 1 and t h e o r d i n a te s a r e g iv en i n t a b l e I .

Both th e fo r e f l a p and the r e a r f l a p were at tachedt o t h e main p a r t of t he a i r f o i l b y s p ec i a l f i t t i n g s t h a tper mit ted them t o be moved and de fl e ct e d independently.Each f l a p a l s o p iv o te d a bo ut i t s own nose point a t anypo s i t i on ; increments of 5 de f l ec t i on were p rovided f o rt h e f o r e f l a p and increments of 10' d e f l e c t i o n f o r t h er e a r f la p . The nose poin t of e i t he r f l a p i s d e f i n e d a st h e p o i nt of tangency o f the leading-edge Erc and a l i n edrawn perpend icu la r t o th e f l a p chord. The d e f l e c t i o nof' eLthor Flar, was measured between i t s r e s p e c t iv e c h o rdand th e chord-of th e main a i r f o i l . The model vias madet o a t o l er a n c e o f JcO.015 inch.Tes ts

The model was mounted v e r t i c a l l y i n the closed t e s ts e c t i o n o f t h e LMAL 7- by lO-foot tunnel and completelyspanned th e j e t e xc ep t f o r m a l l c l e a r a n c e s a t e ac h end.(Se e r e f e r e n c e s 5 and 6 . ) The main a i r f o i l was r i g i d l ya t t a c h e d t o the balance frame b y to rque tubes thatextended through t he upper and lower bou nda rie s of t h etun nel . The angle of a t t ac k o f the model was set fromo u t s id e t h e t u n n e l b y ro t a t i n g th e t o rq u e tu b e s w i th ac a l i b r a t ed e l e c t r i c d ri v e. This type of i n s t a l l a t i o nc l o s e l y approximates two-dimensional f low and th es e c t i o n c h a r a c t e r i s t i c s of th e model be ing te s ted cant h e r e f o r e be determined.


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4 NACA ARR No.&JO5A dynamic pressme of' 16.37 pollnds per square footwas rrieintained for most of' tbe t e s t s b u t , a s t h e f l a p sn e r c extended and th e ra a r - f l a p def3 .ect ion was i n c r e a s e dt o bo0 and 70, i t was' necessa ry t o reduce th e dynamic

pressure because of t h e l i m i t e d p m e r of t h e t u n n e l m otor.Yith t h e c o n f ig u ra t io n f o r maximn l i f t , a dynamic pres-s u re of 14.84 pounds per square foot was maintained.These d p a n i c p r e s s u re s c or re sp on d t o v e l o c i t i e s o f 80and 76.2 m i le s p e r hour under s tandard sea - leve l con-d i t i o n s and t o av er ag e t e s t Reynolds, nu_lnbers of approxl-mately 2.245 x lo6 and 2.140 x lo6, r e s p e c t i v e l y .Because of th e turb i i lence i n the wind tunnel , theeffective Reynolds nun;bers Re ( r e f e r e n c e 7 ) were

I /approximately 3 .6 x 1 . 0 ~ a~ ~J,+ZIO', r e s p e c t i v e l y .I n each cas e, Rew i t h t he f l a p s r e t r a c t e d acd on a Cuw-bulence f s c t o rof 1 . 6 f o r t h e LMAL 7- by 3.0-Toot wind t u n n e l .1s baeed. 03 the ehord o f t h e a i r f o i l

No t e s t s w ere made of t h e p l a i n a i r f o i l nor of themodel wi th the f laps [email protected]$ Pekaocted because thec h a r a c t e r i s t i c s of t h e p l a i n airfoil had p rev ious ly beeni n v e s t i g a t e d and r e p o r t e d i n r e f c r c n c e 1.The optimum f la p po s i t i on s fo r th e va r i ous f l a pde f l ec t i on s were cons ide red, f o r purposes of making theb e s t s e l e c t i o n , t o be t h e p o s i t i o n s a t which e i the r

maxinwn l i f t , minimum drag, OT' minimum p i t c h i n g momentw a s o 's ta ined , a l though , a s p rev ious ly ind ica te d , av a r i a b l e d r a g i s d e s i r e d f o r l a n d in g c o n d i t i o n s .Three p o s i t i o n s of t h e f o r e f l a p were s e l e c t e d i nde terminina va r iou s ex tended pos i t io ns of the f l a p s ora p o s si b l eu p a th f o r t h e e x t e n s i o n o f t h e f l a p s .l e a s t e xte nded f o r e - f l a p p o s i t f o n , h a vi n g a 5 O d e f l e c t i o n( p o s i t i o n l), and the chordwise lo ca t i on o f the in te r -m edia te p o s i t i o n ( p o s i t i o n 2 ) were c hosen a r b i t r a r i l y .The l oca t ion p e rp e n d ic u la r t o t h e c ho rd a nd th e 20'd e f l e c t i o n f o r p o s i t i o n 2 w e r e optimum a s d eterm ined from

a maximum-lift survey w i t h t h e rear f l a p d e f l e c t ed 500and 600. Because of the large nu.nber of t e s t s i n v o l v e di n d e t e rx i n in g t h e o p t irn u n- l i ft p o s i t i o n of t h e d o ub les l o t t e d f l a p , a p re l im in a ry s u rv e y w a s msde t o determineth e optimum po s i t i on and de f l ec t i on of th e most extendedp o s L t i o 2 ( p o s i t i o n 3 ) of t h e f o r e f l a p with t he r e a r f l a pd e f l e c t e d 600 and 70 a t v a r io u s p o s i t i o n s . T e s t s wereth e r ea f t e r made w i t h t h e f o r e f l a p a t each of t h e t h r e es e l e c t e d p o s i t i o n s i n o r de r t o de te rm in e t h e m a x i m u m l i f t

?he


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IJACA ARR no. L4J05 5and th e optimum po s i t i on of the re a r f l a p a t s e v e r a ld e f l e c t i o n s . Data were o bt ai ne d f o r r e a r - f l a p d e f l e c t i o n s .of l o o b 20, 30, and 40' a t g o s i t i o n 1- 30, bo0, 50,and 60 a t p o s i t io n 2; and 4-0 , 50, 606, and TO0 a tp o s i t i o n 3 . 1nasmuch.as i t appea red l i ke l y t h a t onlys m a l l r e a r - f l a p de f l ec t i o ns would be used w i t h t h e l e a s tex teaded fo re - f l a p p os i t i on and t h a t o n l y l a r g e r e a r - f l a pde f l ec t i on s would be used wi th th e most extended fo re -f l a p p o s i t i o n , t h e t e s t s were c on fi ne d t o t h e s e c o nf ig u-r a t i o n s . I n o rd er t o de te rm ine t h e e f f e c t o n t h e a er o-dynamic ch a r ac t e r i s t i c s , t e s t s were a l s o made w i t h t h elower l i p of the s l o t i n i t s normal po s i t i on on t hecon t our , de f l ec t ed l 9 O w i t h i n the a i r f o i l contour ( a tf o r e - f l a p p o s i t i o n 2 ) , and completely removed ( a t f o r e -f l a p p o s i t i o n 3 ) .

No sca l e -e f fe c t t e s t s were niade because t h e r e s u l t sof e a r l i e r t e s t s o f t h e NACA 23021 a i r f o i l with a s l o t t e df l a p ( r e f e r e n c e 1) a r e c on si de re d a n p l i c a b l e t o t h er e s u l t s of t h e p r e s e n t i n v e s t i g a ti o n .attack for maximum l i f t was covered i n 2 O increments overmost of th e range f o r each t e s t ; however , when the s t a l lc o n d i t i o n w a s approached the increinent was reduced t o lo.V ery l i t t l e d a t a were o bt ai ne d f o r ang les of a t t a ck abovet h e s t a l l because of t he uns t eady cond i t i on o f the model.L i f t , dr ag , and p it c h i n g rnonent were measured a t eacha n g l e of a t t a c k .

An angle-of -a t t ack range f r o m -60 t o t h e a ng le of

RESULTS AND DISCUSSIONCo ef f i c i en ts and SpnboLs

A l l t h e t e s t r e s u l t s a r e g iv en i n s t a n d a r d s e c t i o nnondimens iona l coef f i c i en t f o r m c o r r e c t e d f o r t u nn e l- w al le f f e c t and t u r bu l e n ce a s e x pl a in e d i n r e f e r e n c e 6.C t * s e c t i o n l i f t c o e f f i c i e n t ( t / q c )

s e c t i o n p r o f il e - d ra g c o e f f i c i e n t ( do /q c)CdOse c t io n p itching-moment c o ef f i c i e n t aboutaerodynamic center o f p l a i n a i r f o i lm(a.c. l o


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XACA ARR NO, 4 ~ 0 5se c t o n p it ch ing-nomont co ef f i c i en t[C"(a-c*1.3 a t m a x i ; n i m section l i f t c o e f f i c i e n tCZ,,X

OmindwhereZd0m(amc. o9C

VPandRezt

=0

6f2. x1

m a x i m u m s e c t i o n lift c o e f f i c i e n tminimum section profile-drag c o e f f i c i e n t

s e c t o n lifts e c t i o n ' p r o f i l e d m gs e c t ion g i t c h l n g momenk about aerodgnanicc e n t e r of p l a i n airfoil ( f i g . 2 )dynamic pressure (2+pV2\chord of basic airfoil w P t h f l a p f u l l yr e t r a c t e dv e l o c i t y , f e e t per eecori6mass densi ty of a i r

e f f e c t i v e Reynolds xumberdistance from aerodgnari i ic center of a i r f o i lt o c e n te r of p r e ss u re o f t a i l , e x p re ss edi n a b f ' o i l chordsangle of a t t a c k f o r i n f i n i t e a sp ec t r a t i of o r e - f l a p d e f l e c t i o n , measured between fore-

f l a p chord and a i r f o i l c hordr e a r - f l a p d e f l e c t i o n , m ea sw ed between r e a r -f l a p c ho rd and a i r f o i l c hor dd i s t a n c e f r o m a i r f o i l u pp er -s ur fa ce l i p t ofo re - f l ap -nos= po i n t , measu red p a r a l l e l t oa i r f o i l c h o r d and po s i t iv e when fore- f l ap-nose point i s chead o f l i p


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7ACA ARR No. 4 J 0 5d i s t a n c e f rom a i r f o i l u pp er - su rf ac e l i p t ofore- f lap- nose po in t , measured perpen-d i c u l a r t o a i r f o i l chord and p o s i t i v e whenfore - f lap -nose po in t i s below lip

71

x2 d i s t a n c e from f o r e- f l a p t r a i l i n g edge t or e a r - f l a p-n o s e p o in t , m easured p a r a l l e lt o a i r f o i l chord and p o s i t i v e when rea r -f lap -nose po in t is ahead of f o r e - f l apt r a i l i n g edged i s t a n c e from f o r e - f l a p t r a i l i n g edge t or ea r -f lap-nose po in t , measured perpen-d i c u l a r t o a i r f o i l chord and p o s i t i v ewhen rear- f lap- nose poi nt i s below f o r e -f l a p t r a i l i n g edge

Pr e ci i o nThe accu racy of th e va rio us measurements i n t h et e s t s is b e l i e v e d t o be within t h e fo l lo w in g l i m i t s :

a,, degrees . . . . . . . . . . . . . . . . . . . . 0.1'Zmax . . . . . . . . . . . . . . . . . . . . . . *0.03. . . . . . . . . . . . . . . . . . . ~ 0 . 0 0 3'm(a.c. l o. . . . . . . . . . . . . . . . . . . . fo.0003Cdonlin . . . . . . . . . . . . . . . . . *0.0006Cd"(cZ = 1 .0 )

e . . *O.O02= 2.5)d6 4 qd 6 degrees . . . . . . . . . . . . . . . 0.2f 2 'F l a p p o s i t i o n . . . . . . . . . . . . . . . . . f0.001~

No co rr ec t i on s were de termined ( o r a p p l ie d ) f o r thee f f e c t o f th e a i r f o i l o r f l a p f i t t f r r g s on t h e s e c t i o na e ro dy iam ic c h a ra c t e r i s t i c s b ecause o f the large numbero f t e s t s r e qu ir ed . I t i s believed, however, t h a t t h e i re f f e c t ?.s s m a l l and t h a t t h z r e l a t i v e v a lu es of ther e s u l t s would n o t b e a p p re c i a b ly a f f e c t e d .


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a

Fore- f l a pp o s i t i o n

Flain A t r f q i l

P o s i t i o n o f r e a r - f l a p nose 'Ahead of l i p 1 Below l i p( p e rcen t (pe rcen ta i r f o i l chord) 1 a i r f o i l chord)

KACA ARR No. d+JO5

123

The complete aerodynemic s e c t i o n c h a r a c t e r i s t i c s oft h e p l a i n EACA 23021 airfoil ( f r o i n rleference 1) a r ep re se nt ed i n f i g u r e 2 .b ee n d i s cu s s e d i n r e f e r e n c e 1, no further comment i sbe i ie ve d ne ce s s a ry . S i m e t h e s e d a t a have a l r e a d y

6 2.712 3.063 3.31102

Determinat ion of 0p.tbu-m Flap Conf igura t ionsM ax im u m l i f t . - The r e s u l t s of t h e maximum-lift inves-t i g a t i o n w i t h th e for5.e f l a p a t each of t h e t h r e e s e l e c t o dpos i t i ons and with t h e rear f l a p def l ec t ed and l oca t ed a t

p o i n t s over a cons iderab le area w l t h r e s p e c t t o t h e f o r ef l a p a r e presen t ed In figures 3 to 5. The r e s u l t s a r epresen ted as contours of l i f t c m f f l c i e n t f o r v ar io usp o s i t io n s of t h e rear-f'3ap-nose p o ln t a t v a r i o u s r e a r -f l a p d e f l e ct i o ns . TlrJe rs$u3Cva show t h a t a t each fore-f l a p p o s i ti o n , t h e c o n t o w s 61j.d not c l ose a t t he s rnal le rr e a r - f l a p d e f l e c t i o n s i n m s t i p i t e d , A t p o s i t i o n s 1 and 2 ,i t i s i n d i c a t e d t h a t t h e open conccurs xou ld c l os3 a tp o s i t i o n s of t h e r e a r - f l a p nose t h a t would be imprac t i cab lebecause of t h e l a r g e gap b e t w e n t h e two f l a p s .A t ea ch of t h e t h r e e f o r e - f l a p p o s i t i o n s , a s t h ef l a p d e f l e c t i o n i nc r ee s ed , t h e p o s i t i o n of t h e r e a r f l a pfor m a x h m s e c t i o n lift c o e f f i c i e n t

became more c r i t i c a l - t h a t i s , a given movement of t h erear-f lap-n ose po int cai ised a gr ea t e r change i n t he va lueof . S i n c e t h e p o s i t i o n of t h e r e a r - f l a p n o s ef o r c ten ds t o move forward and upxard as i t sd e f l e c t i o n i n c r e a s e s , t b e g ap be tw een t h e two f l a p s i so b t ai n e d a t e ac h f o r e -'Zmaxeduced. The va l ues off l a p pos i t i o n and t he approxi ma te po s i t i on of t h e r e a r -f l ap nose w i t h r e sp e ct t o t h e f o r e - f l a p t r a i l i n g edge a r eg iv e n i n t h e f o l l o w i n g t a b l e :

g e n e r a l l yczInax

CzmaxZX


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PACA A R R No. & J G 5 9From the contours of 1-ear -f lap-nose po s i t i on f o r, h e b e s t p a th t o be fol lowed by t h e r e a r f l a p a tczmaxa l l d e f l e c t i o n s w i t h i n t h e r an se i n v e s t i g a te d , from ac o n s i d e r a t i o n of alone, can be determined. The

range of f l a p pos i t ions covered w a s c o n s i d e r e d s u f f i c i e n tt o a llo w f o r any dev i a t i ons or compromises from the b e s tpath. Complete aerodynamic se ct io n c h a r a c te r i s t i c s f o rth e opt imum-lift and optimum-drag rea r-f lap -no se p o s i t io n sa t e ac h s e l e c t e d f o r e - f l a p p o s i t i o n a r e p r es e nt ed subse-quent ly h e re in .

'%,ax

Minimum p r o f i l e drag.- Drag data obtained w i t h thef o r e f l a p i n the t h r e e s e l ec t e d p o s i t i o n s and t h e r e a rf l a p d e f l e c t e d a t var io us pDsi t ions over a wide regiona r e p r e se n te d i n f i g u r e s 6 t o 8. The data a re presen t edas d rag con t ou rs f o r t h e r e a r- f l ap - n o se p o s i t i o n a tc e r t a i n s e l e c t e d s e c t i o n l i f t c o e f f i c i e n t s a nd r e a r - f l a pd e f l e c t i o n s . A comparison of t h e s e c t i o n p r of f l e- d r a gc h a r a c t e r i s t i c s of t h e p l a i n a i r f o i l ( f i g . 2 ) .w i t h t h ep r o f i l e - d r a g c h a r a c t e r i s t i c s g iv e n i n t h e c on to ur s off i .gure 6(a ) and 6 ( b ) shows t h a t t h e p l a i n a i r P o i l g i v e sth e lower drag va lue a t cz = 1 .0 .

Inasmuch as only a very few o f the con tours wereclo sed about ind ica ted optimum-drag p os i t io ns of the rear -f l a p nose ( f i g s . 6 t o 8 ) ; i t i s obvious t h a t a s u f f i c i e n tr a n e e o f r e a r - f l a p p o s i t i o n was not covered and t h a t thetrue optimum values may e x i s t a t some other p os i t io ns .A t each of th e fore- f l ap pos i t io ns , however , i t fs i n d i -c a t e d t h a t t he con tou rs would c l o se a t po s i t i on s o f therear-flap nose which would be somewhat c l o s e r t o the l i pof the f o r e f l a p than t h e p o s i ti o n s t e s t e d . A s the f o r ef l a p w a s extended and a s t h e rea r f l a p was def l ec ted , theoptimua-drag rear-f lap-n ose po si t i on ge ne ra l l y movedforwayti and up, c l o s e r t o the f o r e - f l a p t r a i l i n g edge.Yore than one region of miniiimni drag e x i s t s a t v a r i ou sva l ues of' s e c t i o n l i f t co e f f i c i en t cz and va r i ous r ea r -f l a p d e f l e c t i o n s and t he minimum dr ag i s s e en t o be p r i n -c i pa l l y a func t i on of sec t i on l i f t c o e f f i c i e n t a n d r e a r -f l a p d e f l e c t f o n and r e l a t i v e l y ind ep en den t of t he f o r e - f l a pp o s i t i o n . I n e ac h p o s i t i o n of t h e f o r e f l a p , as t h es e c t i o n l i f t c o e f f i c i e n t o r t h e r e a r - f l a p d e f l e c t i o ni n c r e a s e d , the con tours ge mr a l l y became more c r i t i c a l o rc l oze l y spacsd ; t h a t i s , a given movement of t h e r e a r -f l ay-nose po in t gen er a l l y caused a Greater change i n thevalue of t h e s e c t i o n p r o fi l e- d r a g c o e f f i c i e n t(See f i g s . 6 t o 8 . ) cdo*


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10 NACA A-RR TTo. &JogInasmuch as th e rea r - f lap - nose po s i t i on s f o r maximuml i f t and minimum drag g e n e r a l l y 20 not c o i n c i d e , a com-

proiii3se i s necessary . The cumes fo r the co rnp le te ae ro -dynamic s e c t i o n c h a r a c t e r i s t i c s a r e t h e r e f o r e p r e s en t e df o r b o t h c o n d i t i o n s .---itching-moment .- Contours cf s e c t i o n p i t ch i n g -moment c o e f f i c i e n t f o r the r e a r - f l a p - n o s e p o s i t i o n s ats e l e c t e d s e c t i o n l i f t c o e f f i c i e n t s and r e a r - f l a p d e f l e c -t i o n s a r e g i ve n f o r e ac h of t h e t h r e e f o r e - f l a p p o s i t i o n si n f i g u r e s 9 t o 11.i n c r e a s e i n the nega t ive value of c a t agiven c7, was obtafned v i t h increase6 r e a r - f l a p d e fl e ct j onan3 t h a t t h e m a x i m i ne g a ti v e vzlues of wereusually obtained a t or n e a r t h e p o s i t i o n of t h e r e a r - f l a p -nose po in t f o r maximm l i f t a t ea ch r e a r - f l a p d e f l e c t i o n(coxpare w i t h f i g s . 3 t o 5 ) . At 6f = T O O , 600, and T O 0a t Dosit ion 3 . however. a decr ease 2n th e vglue

These contours i n d i c a t e t h a t anm(a.c. ) o

Cm(a.c. l o

2- - - was in di ca te d when cl in cr ea se d.f cm(a.c. l oA t a g iven l i f t c o e f i ' i c i s n t and r e a r - f l a p d e f l e c t i o n ,t h e negat ive va lue s of p i tc h i ng moment a l s o increa sed as

the fo re f l a p wrs extended f rom posi t ion 1 t o p o s i t io n 3 .I t a p p e a r s d e s i r a b l e t h e r e f o r e t o use the nifnimum flapd e f l e c t f o n o r e x t e n s i o n ne c e ss a r y t o o b t a i n any g i v e n l i f tc o e f f i c i e n t . I n a d d it i o n , t h e contours i n d i c a t e t h a t t h epos!.tion of t h e rear-flap nose becomes more c r i t i c a l w i t hi nc r ea s ed r e a r - f l a p d e f l e c t i o n and l i f t c o e f f i c i e n t .With these c o n t o w s of flap l o c a t i o n f o r ~ ( a o c . ) o

%n f i g u r e s 9 t o 11, th e des igne r can deteFmine o r an t i c i -p a t e the va lues of c t o be encountered a t agiven value ofd e f l e c tion

y a . c . l ow i t h i n the range o f p o s i t i o n and

Aerodynamic Sect on C ha ra c t er is t i cs of S e l e c t e dO p t i m u m Configura t ions

The com plete a e rod y na n ic s e c t i o n c h a r a c t e r i s t i c s ofth e a i r f o i l w i % h t ha r e a r f l a p a t tn e opt imum-l if t and


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3ACA ARIi No. L!!JOS 11optirnux-drag posi t ions a t each f l a p d e f l e c t i o n and a teach of t h e t h r e e f o r e - f l a p p o s i t i o n s a r e p r e s en t e d i nf i g u r e s 12 t o 14. Ttle consecutive f lap -nos e p os i t io nsa= 6f2 i n c r e a s e s a r e i n d i c a t e d il? t h e f i g u r e s by t h o sekey symbols t ha t ar e connected by dashed l in e s . Thel i f t - c u r v e s l o pe s d ec re as ed w i t h i nc r ea s ed r e a r - f l a pd e f l e c t i o n , a lt ho ug h a t r e a r - f l a p d e f l e c t i o n s below 50,th e l i f t - c u rv e s lope was sometimes as much as 0.03 g r e a t e rt h a n t h a t of t h e p l a i n a i r f o i l . A t e a c h f o r e - f l a pp o s i t i o n , t h e a n g l e of attack for rnaximun l i f t u s u a l l ydecreased w i t h i n c r e a s e d r e a r - f l a p d e f l e c t i o n but i n somei n s t a n c e s r em ain ea f a i r l y c o n s ta n t .

A t p o s i t i o n 3 ( f i g . lk) and 6f2 = 50,of t h e r e a r f l a p f o r maxirium E f t and minimum drag coincide.I r r e g u l a r i t i e s i n th e c ur ve s a t t h e l a r g e r f l a p d e fl e c -t i o n s ( f i g s . 12 t o 14) ndicate changing f low condi t ions.

t h e p o s i t i o n

A t t he sma ll r e a r - f l a p de fLec ti ons and l i f t c o e f f i -c i e g t s , t h e s l o p e s of t h e pitchinqpxoment cur ves weren e p - t i v e a nd , a t h i gh f l a p d e f l e c t i o n s and l i f t c o c f f i -c i e n t s , w ere u s u a l l y p o s i t i v e ; mailer negat ive va lueswere therefore sometimes obtained w i t h aOf m(a.c. l ol a r g e f l a p d e f l e c t i o n t h a n w ith a s m a l l one a t h igh l i f tc o e f f i c i e n t s . (See f i g s . 1 3 an6 14.)Increment of ,naxin;um section l i f t coe f f i c i en t . - The-increGgnt of the maximum section l i f t c o e f f i c i e n t

based on the va lue of czmax of the p la in a i r f o i l ,i n c re a s e s a s t h e r e a r f l a p i s d e f l e c t e d a n d as t h e f o r ef l a p i s extended ( f ig . 1 5 ) . A t e a c h f o r e - f l a p p o s i t i o n ,t h e v a l u e s of Actma, a r e h ig her f o r the opt imum-l i f tpo s i t i on t han fo r t h e optimum-drag re a r - f l a p pos i t i on , asw a s a n t i c i p a t e d .

Actmax,

!?he maximum increnent of l i f t c o e f f i c i e n t o b t a i n e dwas a t p o s i t i o n 3 w i t hi s ind ica ted . The sc al e ef fe ct on th e valu es of Acwas not inv es t iga ted but it i s expec ted tha t the va lueswould incpease s l i g h t l y wit h Xegnolds number with th e0 . 3 2 ~d ou ble s l o t t e d f l a p a s d i d t he va lues for t h es i n s l e - s l o t t e d - f l a p a r r a n g e n e n t s of r e f e r e n c e s 1 and 6.

6f2 = 70, where a value of 1 .96Zmax


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12 NACA ARR No. 4 J 0 5

Envelope polar cwves .- The envelope polars ofs e c t i o n p r o f il e - d ra g c o e E i c T e n t Cd, a t e a c h f o r e - f l a pupos i t i on , ob t a ined f rom f i gu re s 12 t o l,!+ f o r the optimum-l i f t and. optimum-drag configurations, and the polar o f .t he p l a i n a i r f o i l ere p r es e nt ed i n f i g u r e 1 6 .c u r v e s i n d i c a t e t h e C d a v a i l a b l e a t any c7, whenTheseOmint h e r e a r f l a p i s l o c a te d t o g i ve ( f i g . 16 (a ) )c ~ m a xand cd ( f ig . 16(b)).Omin

For bo th t h e maximum-lift and minimum-drag conf'igu-C d Or a t i o n s ( f i g . 16), t h e plain a i r f o i l g iv e s t h e lowest

f o r va lues o f c7, l e s s t ha n 1 .3 , and fo r va l ues o f cbabove 2 . 6 th e lowest value of C d o i s i n d i c a t e d a tp o s i t i o n 3 .

Comparison of F la p Arrangemen tsWhen t h e l i f t - d r a g c h a r a c t e r i s t i c s o f t h e 0 . 2 5 6 6 ~a n d 0 . 1 ~ 0 ~i n g l e s l o t t e d f l a p s ( re fe z- en ce s 1 and 2 ) afidt h e 0 . 4 0 ~ o u bl e,s l o t t e d f l a p ( r e f e r e n c e 3 ) are comparedw i t h those of t h e opt imum-lift and opt imum-drag conf igu -r a t i o n s o f t he 0 . 3 2 ~double s l o t t e d f l a p ( f i g . l?), ti s apparen t th a t the 0.kOc d ou bl e- s lo t t e d- f l a p a r range-ment produced th e hi gh es t l i f t c o e f r i c i e n t ( c t = 3.56)

on t h e X4CA 23021 a i r f o i l . Thet h e 0 . 3 2 ~ d ou ble s l o t t e d f l a p i s cons i de rab l y h i ghe r t hanthat; obtained w i t h e i t h e r s in g le s l o t t e d f l a p but i t i sapproximately 0.25 l e s s t h a n th8.t of t h e 0 . 4 0 ~ oubles l o t t e d f l a p .

obt a ine d w i t hclraax

CdoThe 0 . 3 2 ~ d ou ble s l o t t e d f l a p had a l a r g e rt h a n e i t h e r s i n g le s l o t t e d f l a p for va l ues o fbetween 1.0 and approximately 2 .7 and had a l a r g e rthan the 0.4-Oc double-s lo t t ed- f l ap a r rangement a tall valu es of cz above 1.0,

c bQO

The 0 . 3 2 ~ ou ble -s lot ted -f l ap arrangement h.ad valu esOf Cdo for t h e e nv elo pe p o l a r s t h a t d i f f e r e d b y


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NACA ARR No. aJ05 13about 0.02 f o r t h e opt imwn-drag and opt m u m - l i f t conf igu -rat-f-ons a t a value of' cZ of about 2.5. A t va lues of czl e s s t h a n 1 . 3 and grea ter than 3.1, however, the tw o p o la rc ur ve s p r a c t i c a l l y c oi n c id e .

When the polars of t h e 0 . 3 2 ~d o u b le - s lo t t e d - f l a parrangement on the NACA 23021 a i r f o i l a re compared w i t ha s i m i l a r arrangement of a 0 . 3 0 ~d o u b le s lo t t e d f l a p ont h e TTACA 23012 a i r f o i l ( re fe rence 41, t i s apparent t ha tthe c7 ob ta ined w i t h each i s aDproximatelg the same_ax( f i g . 18). The values of Cd,, however, are h igher a tUa l l va lues of cz fo r th e ar rangement on th e 21-percent-

t h i c k a i r f o i l t ha n f o r t h a t on t h e 1 2 -p e r ce n t -t h i ck a i r -f o i l b u t t h e r e l a t i o n betw een optimum-lif t and optimum-drag conf igura t ions i s about the same for each arrangement .A fur ther compar ison o f t h e v a r i o u s s l o t t e d - f l a parrangements on the EACA 230.21a i r f o i l i n di ca te s t h a t af a i r l y l i n e a r v a r i a t i o n e x i s t s f o r each arrangem ent a t ag i v e n f l a p conf igui-a t io n between th e andc Z m x( f i g . 1 9 ) and t h i s v a r i a t i o n

the [Cm(a.c. )J 7"maxappe ars dependent on th e f l a p arrangement. The 0 . 3 2 ~d o u b l e s l o t t e d f l a p gave h i g h e r va lues of

C' Imaxa t any value of ct than any of t h e s l o t t e d f l a p s .Inasmuch as t h e r e will be a t a i l l o a d r e q u i r e d t ot r i m the negative pitching moment of the wing o f an a i r -p lane , the l o s s i n maximum s e c t i o n l i f t c o e f f i c i e n t i ntr imming the a i r f o i l se c t io n pitching-moment co e f f i c i en thas b e e n c a l c u l a t e d , for th e case when the cen ter ofg r a v i t y is a t t h e aerodynamic cen te r of t he p l a i n a i r f o i l ,f r o m th e fo l lowing express io n and i s i n d i c a t e d i n f i g u r e 1 9 s

- bmax- -.'Zmax ' I tLoss of

m e l o s s i n c has been presented for t a i l l eng thsof 2, 3 , and 5 a i r f o i l - c h o r d l e n g t h s and, by means of t h ecurve s of f i gu re 19 , t h e e f f e c t iv e c c a n b edetermined.

Z m a xtmax


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XACA AR R NO. ~ 4 ~ 0 5Ef fe ct of Various Xo di fi ca ti on s on t h e Aerodynamic

Sect o n a a r a c t e r s t c sE:ffect of moving the t w o f l a p s a s a uni t . - Thee f f e c t on t h e a e ro d yn m i c s e c t i o n c h a r a c t e r i s t i c s ofmoving the fo re f l a p and re ar f l a s as a u n i t p e rp e n d ic u la ra n d p a r a l l e l t o t h e a i r f o f l chord i s shown i n f i gu re s 20and 21, r e s p e c t i v e l y . A 0 . 0 1 ~ isplacement downward oft h e f l a p s , p er pe nd ic ul ar t o t h e c h or d, was q u i t e c r i t i c a li n t h a t a l a r g e d e cr ea se i n l i f t and a n in c r e a s e i n d r a gr e s u l t e d ( f i g . 2 0 ) . Figur e 21 in di ca te s t h a t a movementof t h e f l a p s p a r a l l e l t o t h e a i r f o i l chord had a consid-e r a b l e e f f e c t on t h e a e r o d p am i c c h a r a c t e r i s t i c s ; t h a t i s ,a t p o s i t i o n s of t h e f o r e f l a p dov\lnsl;ream f r o m x1 = 0.70( p o s i t i o n 3 ) , l a rg e d e c re a s e s i n lift and inc rea ses i nd rag resu l ted and uns teady f low co i ld i t ions ex is ted . Acolnoarison of f i g u r e s 20 and 2 1 w i t h the contours off i g u r e s 4 nd 7 and 5 and 8, r e s p e c k i v e l y , i n d i c a t e s t h a tt h e p o s i t i o n of t h e f o r e f l a p is morc: c r f t i c a l t h an t hep o s i t i o n o f t he r e a r f l a p .p c s i t i o n 1 t o p o s i t i o n 2 and then t o p o s l t f o n 3 along t w od i f f e r e n t p a t h s , A and B y gave an inc rease i n l i f t ,dr az , and pi tc hi ng moment. (See f i g s . 22 and 23,) Sinceth e model f i t t i n g s only a l lowed Increments of l o o f o r t h ed e f l e c t i o n of t h e r e a r f l a p , i t was no t pos s ib le t o havef i g ur e 23 a t p o s i t i o n 1.f l a p s a s a u n i t i s onl-37 appr oxim ate ly s im ul at ed , f i g u r e s 22and 23 a r e t hought t o be s u f f i c j- e n t l y i l l u s t r a t i v e .

M_c_- ---

Moving the two flaps approximately a s a u n i t f r o m

a 6f2 of 350 f o r f i g u r e 22 and a 6f2 of 4 5 O f o rAlthough motion of the two

Ef fe c t of t h e a i r f o i l lower -_l i p . - The effec ts ofd e f l e c t i n g t h e lower l i p of t h e a f r f o i l from i t s normalp o s i t i on a t f o r e - f l a p p o s i t i o n 2 and o f removing thelower a i r f o i l l i p a t p o s i t i o n 3 a re shown i n f ig u r es 24and 25, r e s p e c t i v e l y . D e f l e c t in g t h e l i p upward l9Odecreased c z and irrcreased over m o s t o f t h eQfi.#ang le -o f -a t tack range, pos s ib ly because of t h e p o o r lyshaped s l o t e n t ry ahead o f t h e fo r e f l a p when th e l i p i sde fl ec te d. On th e oth er hand, removing t he l i p a t t h ee x t e n d e d f o r e - f l a p p o s i t i o n ( f i g . 2 5 ) had a s l i g h t l yfavorab le e f fe c t on the aerodynamic se c t io n charac te r -i s t i c s a t l o w va lues of c by caus ing a red uc t ion i nth e p ro f i l e d r a g , a nd a s l k L h t l y a dv er se e f f e c t a t high


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.

i$iACA ARR No. L4J05 15values o f C Z . Such a r e s u l t I n d i c a t e s t h a t a smoothers l o t e n t r y ahead of t h e f l a ps may be 6e s i r a b l e , p rov i de di t does not reduce the va lu es ofAlthouph no d a t a were obtain ed a t s ma ll f l a p d e f l e c t i o n s ,i t i s probable t h a t t he smoother s l o t en t r y would be evenmore fa vo rab le under such con di t i ons .

a v a i l a b l e .C7mP.x

cONCLUSIONSAn in ve s t ig a t io n via3 made 5-n t h e LMAL 7- by lO-foott u n n e l of ar, XACA 25021 a i ? f o i l n i t h a double s lo t t edf l a p havfne a chcrd 52 porccc t cf t h e a i r f o i l chord ( 0 . 3 2 ~ )

t o det er iq lns the ae roayzsmic se:..l;lo9 c h a r a c t e r i s t i c s w i t ht h e f l a 2 s d e fl e- ct ed a t va.?icus pos i t i ons . T he results oft h i s i n v es t fg a t ic n show izliui,:1. T!ie 0 . 3 2 ~dm.bl3 slottec?. f l a p o n t h e NACA 23021a i r f o i l gave a maximin71 s i lc t - lon l i f t c oe f f ic ie n t of 3.31,which was l a r g e r t h a n t 5 e valas. obtaine2 w i t h t he 0 . 2 5 6 6 ~or 0 . 4 0~ s i n g le s l o t t e d f l a p s and 0.25 l e s s t h a n th e valueobta ined w i t h t he 0 . 4 0 ~ o u b l e s l o t te d f l a p on t h e samea i r f o l l .2 . The values of t h e p r o f f l e -d r a g c o e f f i c i e n t o b ta in ed

w i t h t h e 0 . 3 2 ~ c ub le s l o t t e a f l a p were l a r g e r than t hosef o r t h e 0 . 2 5 6 6 ~ o r 0.f;Oz s i ng l e s l o t t e d f l a p s f o r s e c t i o nl i f t coe f f i c i en t s be twf j sn 1 .0 and approximately 2.7. A ta l l va lues Gf t h e s e c t j o n l i f t co e f f i c l e n t a%ove 1 .0 , t h epresent a r rzngement hed a hfghe r p ro f i l e drag t h a n t h e0 . 4 0 ~ d ou ble s l o t t e d f l a p .3 . A t a gfveri va1v.e o f the maximum section l i f tc o e f f i c i e n t pso?-ic.e% v a r i o u s f l a p de . f l$c t ion . s , t h e0 . 3 2 ~ m b 3 . e sL~:~:,t:.:~Cfi,?.p Gave negat ive soction p i t c h i ng -mornen2 c o e f f i c i e n t 3 t P z t w e y e h?.&er t ha n tho se o f othe rs l o t t e d f l a p s 02 the same air i fofl .4.The 0 . 3 2 ~ o1lbl.e s l o t t e d f l a p gave approxim atelyt h e s a m mazinum l f f t c oef f i c te n t a s , bu t h i ghe r p r o f i l e -d r a g c oe f f i c i e n t ove r t h e e n t i r e l f f t range than, as h i l a r arrangsment of 8 0 . 3 0 ~double s l o t t e d f l a p on a nNACA 23012 a i r foP1 .5 . Moving the f la p s s l i g h t l y from th e i r optimumpo s i t i o ns sometimes proved c r i t i c a l agd re su l t ed i n 8


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16 NACA ARR No. LkJO5l a rg e increase i n draag arid. a r e d u c t i o n i n l i f t .p o s i t i o n of t h e f o r e f l a p a p pe a rs t o b e more c r i t i c a lt h a n t h a t o f t he r e a r f l a p .

6. D ef l ec t i n g t h e l ow er l i p of t he a i r f o i l l9Oupward genera l ly decreased the se c t io n l i f t c o e f f i c i e n tand i n cr eased t h e s ec t i o n p r o f i l e - d r a g co e f f i c i en t o ve rm o s t of t h e an g l e - o f - a tt a ck r an ge ; r em oving t h e l i p a tt h e ex tend ed f o r e - f l a p p o s i t i o n r ed u ced t h e p r o f i l e d r ags l i g h t l y i n t h e l o w e r - l i f t r a n g e but w as s l i g h t l yunfavorable a t h i g h s e c t i o n l i f t c o e f f i c i e n t s .

The

Langley Kemorial Aeronautical LaboratoryNational Advisory Committee f o r Aeronautics'Langley Field, Va.


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._INACA ARR NO. d+;r05 17

1, Yienzineer, Carl J . , and Harris, Thonas A . : Wind-TunnelI n v e s t i g a t i o n of an F. A. C. A. 23021 A i r f o i l w i t hVarious Arrangements of S l o t t e d F l a p s. ITACA Rep.No. 677, 1939.2. ihischik, Frank: Yiind-Tunnel I n v e s t i g a ti o n of an1T.A.C.A. 23021 A i r f o i l with Two Arrangements of a40-Percent-Chord S lo t t e d Fla p. NACA TN No. 728,19393 . lamis, Thomas d., and Recant, Is id or e G.: Wind-Tunnel

I n v e s t i g a t i o n of NACA 2 312, 23021, and 23030S l o t t e d F la p s. NACA Rep. ho . 7 2 3 , 1941.'Vind-Tunnel Invest igat ion of an VASA 23012 A i r f o i lwi th a 0.30-Airfoil-Chord Gouble S l o t t e d F l ap .

Ai r fo i l s Equfgped with 4O-Percent -Chord Double4. P w s e r , P a u l E., Fi sc he l , Jack, and Riebe, John 14.:

FACA AR R NO. 3 ~ 1 0 , 343.5. Ha r r i s , Thoinas A . : The 7 by 1 0 Foot \!rind Tunnel oft h e F a t i on a l Advisory Corn i t t ee for Aeronaut i cs .NACA Reg. No. 412, 1931.

I n v e s t i g a t i o n of an N.A.C.A. 23012 A i r f o i l w i t hVarious Arrangements of S l o t t e d F l ap s . NACA Rep.No. 664, 1939.S e c t i o n C h a r a c t e r i s t i c s a s A ff ec te d by V a r i a t i o n sof t h e Reynolds Number. E I C A Rep. No. 586, 1937.

6 . J e n z i n g e r , C a r l J . , and Ha rr i s , '~ 'honasA . : ITind-Tunnel

7 . Jacobs, Eastman N., and Sherman, Alb ert : A i r f o i l


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YTACA ARR TO. ~ l 4 ~ 0 5 18

II ..orlrlrlrl I I I L i i i a i

I

h4 k I

. . . . . . . . . . . . . . . . . .O c u ~ L n aa3coa3a3a3 E - L n z j - c U r l I1 1 l 1 1 1 1 l 1 1 1 l 1 1 1 1


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N A C A A R R N o . L4J05 Fig. 1

Chord line

Fiy u r t /.- Sec fions o f t h e N A C A 2302air fo i l and the 0 . 3 2 ~ouble sloffedflap.


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N A C A A R R No. L4J05Fig. 2


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NACA ARR No. L4J05 Fig. 3

Percentui/foilcbord@J sf,10:


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Fig. 4 N A C A A R R N o. L4J05


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N A C A ARR No. L4J05 Fig. 5

8 6 4 8 0 - & - 4 - 6


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Fig. 6a N A C A ARR No. L4J05

percent ah oi l ch f dla) c c - 1.0; 6&-10:

WA l WWA L ADVISOIVM Y Y l l l t E FO1 AEROWLUIICS

Percentuirfoiilchord69 cz-/.5; + = 20:


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NAC A ARR No. L4J05

Percent&fa7 cw(el cz= 1.5; +2= 4.0..

Flyore 6.-ConcJuded.

Fig. 6b


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Fig. ?a N A C A ARR No. L4J05

NAllUNAL A D Vl SOl VI%MYlIltt FOR AERONAUTICS


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NACA ARR N o . L4JC5

.

6 4 0 - Z - e - 6

f igure ,?- Conchded.

NATIONAL ADVIWRVCUYYIIIEE FOI t R o l l A U I I c )

1Fig. 7b

.


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Fig. 0s N A C A AR R No. L4J05


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NACA ARR No. L4J05 Fig. 8b

Figure8.- oncluded.


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N A C A A R R No. L4J05

(e) ct 11.5~ 40:

Figure9.-Concluded.


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F i g . 10a N A C A A R R N o . L4J05

Percent airhi/chord

-Percenta/ifoi/chord


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N A C A AR R No. L4J05

4

f yure 10.- oncluded.

NATIONAL ADVISORYCOMYlllEt FOR AtRONNITICI

Fig. 10b.


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F i g . 118 N A C A A R R No. L4J05

.


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\

NACA AR!? N o. L4J05 F i g . llb

Percent u;rfoil cbord Pefcent airfoilchord(e) -2 , sf,60'. Cf)Cf 30;b6 -60' .

f / yure / / . -Conc/uded.


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Fig. 12a N A C A ARR No. L4J05


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N A C A A R R No. L4J05 Fig. 12b


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Fig. 13a N A C A A R R N o. L 4 J 0 5


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N A C A ARR N o . L4J05 F i g . 1 3 b


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F i g . 14a NACA A R R No. L4J05


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N A C A ARR No. L4J05 F i g . 14b


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F i g . 15 N A C A AR R No. L4J05


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N A C A ARR N o. L4J05 Fig. 16a

Figure /6.-rof/'/e-drcrgenve/ope p o / p ~urves f o r the NACA 23021a/ r fo/ ' /w; fh a 0 . 3 2 ~ oubie s / o f t e d f/ap.


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Fig. 16 b N A C A A RR N o . L 4 J 0 5

Section lift c oe f f i c i e n t , c2(b) Rear- flap positions fo r Cdomin.f / gu re /e-- onc /uded.


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N A C A A R R N o . L4J05 Fig. 1 7


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F i g . 10 N A C A AR R N o. L4J05

Section l ift coefficienl-, czflyuric 18.- ompcrr/j.anof sect ionpruf i /Qdrag coeff icients f o rsimi /ur doub/e-s/offed-f lap arrony Qments on t h e N ACA230/2wnd NACA 23021 a/r fo / / s .


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N A C A A R R No. L4J05 Fig. 19


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F i g . 20 N A C A ARR No. L4J05


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N A C A ARR N o . L4J05 F i g . 21


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F i g . 22 N A C A ARR N o. L4J05


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N A C A ARR No. L4J05 Fig. 23


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F i g . 24 N A C A AR R No. L 4 J 0 5


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N A C A A R R No. L4J05 F i g . 2 5

Documents

National Advisory for Aeronautics (1944)