Effects of compressibility on the maximum lift characteristics and spanwise load distribution of a 12-foot-span fighter-...

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Material Information

Title:
Effects of compressibility on the maximum lift characteristics and spanwise load distribution of a 12-foot-span fighter-type wing of NACA 230-series airfoil sections
Alternate Title:
NACA wartime reports
Physical Description:
13, 15 p. : ill. ; 28 cm.
Language:
English
Creator:
Pearson, E. O
West, F. E
Langley Aeronautical Laboratory
United States -- National Advisory Committee for Aeronautics
Publisher:
Langley Memorial Aeronautical Laboratory
Place of Publication:
Langley Field, VA
Publication Date:

Subjects

Subjects / Keywords:
Aerofoils   ( lcsh )
Compressibility   ( lcsh )
Aerodynamics -- Research   ( lcsh )
Genre:
federal government publication   ( marcgt )
bibliography   ( marcgt )
technical report   ( marcgt )
non-fiction   ( marcgt )

Notes

Summary:
Summary: Force and pressure-distribution measurements were made on a fighter-type wing model of conventional NACA 230-series airfoil sections in the Langley 16-foot high-speed tunnel to determine the effects of compressibility on the maximum lift characteristics and the span-wise load distribution. The range of angle of attack investigated was from -10° to 24°. The Mach number range was from 0.20 to 0.70 at small and medium angles of attack and from 0.15 to 0.625 at very large angles of attack. In the Mach number range from 0.15 to 0.55, the maximum lift coefficient first increased with increasing Mach number and then decreased rapidly after having reached a peak value at a Mach number of 0.30. At Mach numbers higher than 0.55, the rate of decrease of maximum lift coefficient with Mach number was considerably reduced. At these higher speeds the lift coefficient continued to increase with angle of attack well beyond the angle at which marked flow separation or stalling occurred, and the maximum lift coefficient was reached at angles 10° and 12° beyond the stalling angle. No significant changes in the span load distribution were found to occur below the stall at any of the test speeds. When the wing stalled at high speeds, the resultant load underwent a moderate outboard shift, which resulted in increases in root bending moment up to about 10 percent.
Bibliography:
Includes bibliographic references (p. 13).
Statement of Responsibility:
by E.O. Pearson, Jr., A.J. Evans and F.E.West, Jr.
General Note:
"Report no. L-51."
General Note:
"Originally issued November 1945 as Advance Confidential Report L5G10."
General Note:
"Report date November 1945."
General Note:
"NACA WARTIME REPORTS are reprints of papers originally issued to provide rapid distribution of advance research results to an authorized group requiring them for the war effort. They were previously held under a security status but are now unclassified. Some of these reports were not technically edited. All have been reproduced without change in order to expedite general distribution."

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 003614876
oclc - 71262451
sobekcm - AA00006270_00001
System ID:
AA00006270:00001

Full Text
Vt


NP^CR L[


NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS





WAllTIll ME RE PORT
ORIGINALLY ISSUED
November 1945 as
Advance Confidential Report L5G10

EFFECTS OF COMPRESSIBILITY ON THE MAXIfIM LIFT
CHARACTERISTICS AND SPAiWISE LOAD DISTRIBUTION
OF A 12-FOOT-SPAN FIGBTER-TYPE WING OF
NACA 2'-SERfIES AIRFOIL SECTIONS
By E. 0. Pearson, Jr., A. J. Evans
and. F. E. West, Jr.

Langley Memorial Aeronautical Laboratory
Langley Field., Va.


NACA


WASHINGTON
NACA WARTIME REPORTS are reprints of papers originally issued to provide rapid distribution of
advance research results to an authorized group requiring them for the war effort. They were pre-
viously held under a security status but are now unclassified. Some of these reports were not tech-
nically edited. All have been reproduced without change in order to expedite general distribution.


DOCUMENTS DEPARTMENT


L 51





































Digitized by the Internet Archive
in 2011 with funding from
University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation


http://www.archive.org/details/effectsofcompres001ang






U.-AJA ACR No. L5G10

NATIONAL ADVTSORY COMMITTEE FOR AERONAUTICS


AD- !3I CC: :,DET.IAL REPORT


n?...,I. ,II C .CiE : e ..r 1.-" -.:T7i LIFT



C'? 12-I"-CF --'I,-'- I l- CF
n- J I-L Z TiTI(-IT

r, E. GC. F: :"-': *T A. *J. E;;-s.
L,.& 1" i ", _. ', *.





Fc.rce sr. red r : r.e-di stri ution r s-c- 0 arcr, e- n c c ere
made on a f'ir r e:--t :e vwi. r .:.1 of f ,-.- -t onr -l
iT!ACA.C 2 C- -iet i: -- r .: in .l J.-. : 10-faot
hicK: ..-,e-:i. t :.-,l t- c"t -t. ? ..V: th ee -- o, re.-- i-
bil- t thee -:i. '- ;. 1l c. s .- .. e .- t c a., ,t n-

:-i I..
vwise lo?.,J c'.i tr-l-;.>r.,.:*'. .. := T -, .. ..E :i n-" ,,f att ,2.: ,:
irve tica- er ': .:- ft :n -1i '- to h h :ber r-n .e
was from ,.C2, t. 0. t 7.-aii ainC. :-ediu ..rL e f attack
and from 0.15 .'., ', C 'rr -- 1 rre r-.ries f ttac::.

In the i.'.a:h nur.'zer r-rgre frm '. 15 t 0.5 ',5 theF
mnaxiru.m l t c ieff' i': c nt -'r.t ino .t : ','ith rnc re :si3r.7
i.Ccnf ...-...' a" .e'r.>-,r se -ra '_I--r. ter ha-,',inr
re. cea ec a ;'ta.: ''. t a ch r :. .:..f ,..-0, at .[., c:
nt.:'l ;-T r : i- e" '.Ih,.- '- r :. : r 2,e i ,..2i r^- .-es ,i :n. :t i;,..]tri
lift cce:-"-ci -; c r- irr ": '.. -1. z .:.-_er c .:..- c,-_ -, -- !" ,'J.-..ed.
At J t": e f-1-. li :. c it i. u-iI to
Ain.' P r e 'v.-_t' :. le I f .c i:c..? .;: ,1 .-'- tiE :i. n l at
whl ic" r. ..r: :e, f- ,r. re a T.-. ,; -a,,-. tii-- 7.,1',: "': _, rn
the .a -i:"j.. li 't c l i 'L rT r -. a.." : l'-

to 1I'' c .-n t1-: r aL --l .

Io i ini -,- n cl-.-,,.i ,s in t.e s<,an l :-d1 di- :tr.ib.tio:i
wer. f,.,' to:' cu r ic' -he :t: all :it r:;-- -f th-: t st
sfeeCs. ."-n the 'i-, sta iil .:.t i;h :-rm. c s, the-.
result nL l,- ad unce. -. "'nt S ,',Jerat- .:.iut. :ar. SLt ift, wla ch
resulted r i i :ease iin ot '--din;- r .: =rt 't. to about
10 p-,rrcent.







NACA ACR No. L5G10


INT TRODUCTIOIT


Wind-tunnel tests of a rectangular wing of NACA 0012
airfoil section (reference 1) showed that the maximum lift
coefficient reached a peak value at the low Mach number of
0.19 and decreased rapidly as the L.. number M was
increased from this value up to the highest .T-.:- number
of the tests (Mi 0.35). Although these tests were
necessarily limited in scope, they indicated the importance
of a knowledge of the effect of compressibility on the
maximum lift coefficient both in the estimation of the
maneuvering performance and loads of high-speed aircraft
and in the-interpretation of wind-tunnel maximum lift
data as applied to the-prediction of airplane character-
istics at low speeds.

More- recent two-dime.nsional. wind-tunnel tests of a
number of propeller-type -airf.oils over a relatively large
is.iC number range (reference 2) showed effects for the
thicker airfoils similar -to those .o.f reference 1 and in
addition .showed large-increases in the maximum lift coef-
ficient starting at iach -numbers of about 0.5. Flight
tests of fighter airplanes reported in references 3 and 4
showed..large decrea-ses in the lift coefficient corre-
sponding to the stall.up to Mach numbers of about 0.6.

A high-speed wind-tunnel investigation of a number
of three-dimensional wings of different airfoil sections
has been undertaken to provide more detailed information
on the -high-speed stalling phenomena. Measurements to
determine the' effect of compressibility on the spanwise
load distribution were included in the program because of
the related importance of the load distribution as a
determining factor of the strength requirements of wings.-
The present report gives the preliminary results of force
and pressure measurements in the Langley 16-foot high-
speed tunnel on the first of a series of wings. The
model tested was a fighter-type wing having an aspect
ratio of 6, a taper ratio of 2:1, and conventional
IIHAT'. 230-series airfoil sections.


CO7 TDE:?I AL


CONFIDE_' IAL









TACA ACR :T,-.. L5C-'10


V trp."c QCrr l. fe t IC second

Sc:ree, 71 cf :, il,:' in .iii.r ft r ,.rec ,_nd

r,': "'A r. er ( )

p ir. r -;.=n t ', -1 r .. i-i-. ,' --- f 'ot



R 1R n', .' n'.:. i'e, -
p r, /
p coefCxiciernt .',f '"i co-ity :.f :ii. ,'ILo- rer
Lact--ecord

iTn f-i'rc in-: ad- ':ol e i-t tM u .:ii tui ed
st rea t-. value .

C C ior.- '.:- : .-..1 -C r A c. r r t1 ..t tlir. s t,


D eq i .- I Ci. .ne g P > -. tiv ti.-;n-l te -t r e:-t on,
s- / /.c ,


S v.inf ;-re j.:u-.--e feet

b vi; .i _n', feet

7 s : n ..- :! .: _e m' r 1i f r.n the ;l e d.:'
.. 1. L

c. aii f.il ch'r.,", t pl- n .:f -- :"me-i ..., feet

r,.e t 1 ch:.,rd, fe 1 2 )

. ..I, C*i2L At : 11-IHe lc feet

t 1- ii.r r'-.. r, ; % i rf.-I fl-r. i.,n CO? .-.. f..hn'.ing
T : r'- '- 9.:-, O_- :.ri i e t


C C' F I LIBi? ThE


C D':I D 7i". AL


'7.,-,- Q
L._ ,_ .







4 CC'ITIDE.'IAL NACA ACR No. LSG10


L wing lift, pounds

CL wing lift coefficient

n section normal force (force per unit span), pounds
per foot

cn section normal-force coefficient n I

c load coefficient
cs / b
I c .2
0C, wingp normal-force coefficient 2 -V 4 c -cn dy .


a corrected anPle of attack of the root section.
(section at the plane of syrm-etfry), degrees

dALL angle-of-attack correction due to the jet
bouni.nrv-induced uopwash at the lifting line,
degrees (57.3 6 5 L)

8 a function of the ratio cf wing span to tunnel

diameter 1 + 4 b 8
16 \D/ 64 D
da3SC angle-of-att'ack correction due to the jet
boundoary-_induced streamline curvature,

degrees '-5 Dl JLL\
\l "


APPARATU.S AND -TTHODS


A diag.ra.ratic sketch of the -"ig model used in- the
tests is given in figure 1. The ohrinci.-1' dimensions
given in the fig-ure and other pertinent information are
given in the following list:


COTTPIDE-TIAL









.,ACA ACR -o. L5G10 CC'I;FIDE:TIAL 5


p t . . 1
Sft . . i

T .=-. c t . . .
-'"c rit C :. -; or -.: n..A lic ti"; "t '. ut) *:', 7 ,

Tip < .r 'on .. .. .. 7.'. .
ihec ...al ( i. c r: le 1i chcr'1 line) ..e .
7s':eep.:ac!: ( il:n -L. 4 ch .ra line), cec 18

The .i:ng :.- :. i ilt-.p :- 61 ,? -,-,tm:' \rtio:, sand m ." s
mnE.chine.d in vuch a ;a::Lre: A.'it s. f ce eCle:..ent-t c DTL'",iecting
eq, al perce.-.ra e-cl-w,,-.-, _, :., 7 r h- roct ac ,i t r .-1tia-,-s
:ere st ra 1-.t lines.

Thirt--tr re :e-'e r e r'ifi -e se i :tr t''.t d c 'er
each of sI 'i ?.-- c -.n-, t :-.. ,:a-'' Fe L. atiot:? ..:rich
are i' en i, -1 :-e .'e c ro ."' i st" .i :l i:r. .f
presz,.'re ifi.:s -.' a t--'ical :ec t n i ?l.:o 'h A in
fi;:ire 1. T : r: -ure t' .'Iere or .u-1. t o t of t.e "'i.In
to :n ltir.lc-t ; :.,e er -- i t e t c -- .:e L :ieans
of the bt, :.. .nt L.r...- i.n -
iure .' th i r T te-t -.e 'tco : rr u.t *.' -
removed i-d 'I-,e -.. re c l.:ce '.ith a r :ii r-. '.sich"
is .shown iL: fi, ire i.

The *-n. 'n.as ,.ntel. a -t the t1um:el e r.ter llne r
shielded .?ru : h -.- ncr a tlic.:ness-r.:or.. ?ti. of 0.15.
The te .i .r.e K-t r. rac i c c'e '. '..a? C. 4. -
ure .3 i a .'-ac o r'h f '. he -u inc sc.-ntc: '..'- r-c' in Vie
t'-r.el c r the for- te es..

I -.: rcf -:.> te-t r _-J : e-*e : ith ':. L-'? of
a c :c. -. .,.:- t .-'t :.',', 'i e : e turL "iel S. n e 'I .- .. ied
fr',' aboit 150 ailes 1 r he .i. t- t: :-._r.'.r: -e
a'.. _r".ir 'abl in-, c-, -r -vin. -_ :.'_ f.' at -- :,..: t' e_?- C
an 4 .Ei..- a.:,.r ..:i .t, elr- 20 11 s 3 ere 'u .- r. 'The ccrr.e-
D .C r nc.... -.. .. .r -e i C _x 1. an
t e c:r -= -c n.. i e:.rC .F :-. e s
fr o > e- t" :-. 1 x 1 i e- e -I .:. -
t .i- n 3f' '- er.e .en .-i n'.- --.:? .-;i- i- :-- :.,- c
ve ; i r-'- iC s -" : f :.t c: -"1.t i.L-.--L-,0 .:; ts : .' l e1
Lu ,.el s eed -l a -:,'t -' .[* 1 A 16 iE .:i.-, :..: rre-
s-'of-ds tI a [ac.h n.r,;:.er cf acut 0.i,'5. In -i e d ter-
i'.:i r i -..c o .a; --i..:.u,i li-t ,c ; :..- .e ra s a .... t i nt 1 ects
'.e-e ...e ,itfh th? t;n -iel r. ,e held. o ;sta',1 while the
an e of attac- "'- -. -ied in rl- recio.e ne ,r r -a:u -u
lft. The *7 on.e c_-le-of-att ck r.ane f' t'-= teots
v i os from -i', t.: '4c
C,'I ,IDEi: 'I.L








YACA ACR 'D. LSC10


in the lood-distribution te-ts' the static pressures
over the six wing sections, as indicated by several
mul tiple-tube manoreters, vere recorded photographically.
The chordwise pressure distributions determined from
these photographic records 'ere integrated echanicall-'
to find the e -ct i1 normal-force coefficients.





Force data. The force data have been corrected for
strut tares, air-stream misalinement, and tunnel-wall
effects.

The strut tare forces were deter -mined from tests
with the wing inverted with and u-ithut image st.:' :rt
struts I installed. A photograph of the inverted : win2 with
tohe image struts instal ed is given in figure 5. The
largest increments of lift coeffLci ent due to the support
struts v-ere between 0.07 and 0.04.

The effective miLsalineTrent annle of the air stream
was determined front te ts of the .in, u-ri .ht and inverted
with the image struts installed and was found to be constant
at 0.150 throughout the speed range of the tests.

In order to prevent air leaCkae through the strut
shields, thin rubber diaphragms were fitted around the
bases of the shields An additional correction to the
lift was necessitated because of a pressure differential
across the disphragms. This pressure differential was
measured during the force te,-tE by means of a nicro-
mancmeter, and a calibration was ~:sde with the wing
removed to determine the variation of lift f force with
pressure differential. This correction was very small
in the region of maximum lift (less than one-half of
1 percent at all speeds).

The effects of the tunnel walls were accounted for
by the methods of references 5, 6, and 7 as follows:
The principal part of the angle-of-attack correction
given in reference 5 is

-ALL = 5.36 CL d ee

This equation is strictly valid only for the case of an
elliptical spanwise load distribution. A check calculation
CO -IDEKTIAL


CONFIDENTIAL








ITACA 2 No. L5G10 CCTT DI' TRIAL 7


by a more e-xact but more detailed procedure based on the
e::_ erinentally determined span loading revealed that the

'l-i :. -.;. "'- i "" f- .7 :,." : ": L 1' of 1.0 thIe ":e.E: t"ia r


A: .. .:'' ect -n t .-r ie of ttta c..:
due r n nr: ",ced ci .t re : L .:. ; c cul:. 1


D o2 S. e e ', L .
and_ .. to.,
/-1 T I-

iThis e-.,.a ion is ba-e ,: e ,.: i i:- .. :,".r-e--- itl he-
cfl T o e 1 7 ..- F e. o::a "... n.
., r' '- .. '_'. 7 _" 7 ,, rr t -. I U c i 1

'ach riL..< CLr .'. .

C.r.re _ct t. h- i : : .. .a vre:sure,
and :;r.ch : ;".. .:" : te... c n- it : i-i:t Cue to
con'stic'-e.:r. effec ;--r ca a e r.'.e -.etI':d :'-'
re.fere .e '. a-.'" '' : ct r e '. i-- i .



)- 4 I-


ct S '-c t .La o ama 2 :.re the :r &d.t' Ar.d fii t c1
a rectar-'m'lar ur.tnel. c: 5 CE:, is the .;;n- p rof 11-:1rse
coef ici Z The t'-,' e ns of .e 1 t the en fi n
tgiv? the v loci ; i -cre -e. t. d'i e, -- ec ly, :. tu"' solid'*
co tfrlct:.-r an- ".':a.:e 2r s:r cr.-- i : .ne S".- .: the f e a :iitu.de
of the -'_:e c::nw-,. {-ti,?n effect i a f-''ic' ti.n of the -elo -city
lo. i : --'" .: "-_" r.'r" ize :' t th e- r e* ti U n
i? exrre-sec ir. re."' ,- :f t::e or .,-.f. ':- 'h ich also -' n .t. : of th" e. .c. w '. r .r

c the.re. ical r' ea9 n. n 3 ']- 1e _r:.:I le.. of c,,'I triic-
ti-)n :ffe r,: fi:. :, ?:-- '. e .* ,-- i- -i c r,: .,r tur -el ;:iets
at the r'r I-ent t i_ ar: :.. '- -e .::_ r I- t r z- h
t-_ re:.r--Cent :r.e e.-t :.'ai la l. e ..:-r... r.. r-i, AT p,:.:ified
for the :a-e if' the i: rcwl .-el, .he e' i'..Ati '-- ecr,.e

_r ,-'',.6 t +. __c,
-( .>)20 4>: KI i2

2: OK- ID:::TI AL..







( 00: ....IL UAC" T 7-` L -10


where -a in this case is the .. eg height of the tuel
in the regio occupied b, the iming. The_ constrictior.
corrections to tIe dy-namic pressure, -:ac-h nu nber (refer-
ence 5), ad. v:in- lift coefficient are as o Ilows:

80 2AV


--S 2-Q
1-= 1 + 0.2T


C Q


The corrections r: ere small f. r low anrcle of attLc over
the r nire ch .n.u-:;er range. At a georetric an;le of
a c. of a a n r of .7 th corrections to
the lift coefficient .nc ach n r ere, respctively,.
1.0 percent and 0.6 percent. At angles of at.acc above
cthe stall here te drag becere very lar'e (-n1icm.tive of
a 'lare vaie)) the corr~c<-iois aOeri f7oe i o,-tance.
At a eor.eKi'o an"ye of attac- of 24 arn a lach number
of 0.6 the correcon:. th lift co cient a.-----. .ach
number were 1. 2 percent nd .2 percent, r espectively.

P.e s s ure-Ftribution data.- The res sre-cIstrib-ution
data e... ,,ca crecreo for oe principal effects of trhe
support str at in t"-at the free-st-ea val ue of static
pressure and .-Inainic pressure upon v: ich the .r-s3ure
coe:fficients .ere based v'era rete:m'insd ifr-. a survey of
the flow in the test section -ith the support struts and
shields installed. Some pmall lo_-l effects of the
struts on the sani.-se load distribution re.ain. -.-:- se
effects .will be discussed in the section entitled "Results
and Discu ssion."

The effect of the tunnel "alls orn the ,? .. load
distribution wasa considered "nd found to be very '.rall;
consequently these Cdata as presented are uncorrected
for tunnel-'wa.l interference.


.""- ~~_.,- I TU'_O "


4Wing lift characteristic! (force test res.lts).- The
lift l..:: :.::- 'ie:: ,: ... ..:. .- 7, :. :,- :-' ---ie








NACA "? 7-. L5C-10 COFT'L l. TAIT 9


cf a t -- .: c. 9. c f-.l.u. er re sl.- i.. P .-. *:i '
Fi-" i re ite- .:' in .r.:. i:e o t-" ter, of the
Se t .-. t t i r i :L_ T 1 e r
or ta-n-.i ,_. 'he 7.a..e J:tae .: t-P c'.e- t' E-,.oint ?.lT S 1-
rP. -., 'e- 9-, the -'-:. zontal i--- :r.:nm >,',r c .-.-tar.t
az tcn :- : ce a-- of a*ria'. .di ;-.,. :' fi -re 7.

*he '-.-"i -'1 ri of) ].o': c f'_.'itt .t .

w -ith .c.: n.-be, ir I-,*. ". r ;',-rr'v "nh: rma:-:im:.'t litt

a :.3 : r :-''er -' 1' a t t :.... ,'' :. ., -..

e' rd ..-. .: .': 3 : -:f .c 'u .. ..- -t.'.+.,'* ;-: :,,% i- i' ? *.-L,.1',- C r c t
. .: a n .. ..... .
it c. I e E t -. ; Cnt

c.e,?_~e r --,:r : t --. .:. 9 :I : .: -. i .f ..- .'. u.iu nl'.i ? eir

.f "... .,. :a ? C .-: T :. :' : 0 .5

a : ." f .-* t : -." iet-;' -.:c- -; '-i.'. :- rc Tt. S-
f'i& = t :. nJ:. t ,. t .


-a,-a L i. .. nt- d t' f-a : -

:i t .: .lu :- '. .-. --.. ,- -. :_ ...Z -" t: t t .: t
D- -




- h, ...... r -,.. .


o .' .' '.. c. 5 -." 1 1 ..: e F e
r *- 1 r- 1 a.:y .Lel7 t .. -. .-.t ..-c

Tch i; le of :ac'c 1C'-' U 1:: ;-n:r 1 Yin :9.it
at i 'c.0- or9 e- 1 1 -n .
T'1 a i.. .. : r


r. te 1 t .21 t e:.- t_. i -.. .
t.. n ( ;-- .e. t .-:. t :. '



t'j t r-at t'-mvi. n'. L '. ti.c _.'t w' -: ir.i. :.. : -, e -ficient
o "-' '. ... t I. l ~".-'" -, : -. r' cr, -.
c prre :r-:'i to :> ns-e I!: :l;-rt -- -' rv *: -f
,r- --_e *, i ...a in .'a. i '-l t decreases
in ".' r. r l. .- e .:.. .el.y -,a '-,'.'-i. Tt 'i rP. c expected
o 'c re'. ,v "-. : i. ,r-,.,.: : r1 .r v.- nt rto
.~,:-.l 1 *'.il. :' i :l' r r : .: .-r : i t : C the
:-r'>.t t )c e fic .1 c Li. L r e. rle f: e (-- i'e -c )-. Thus,
L :11 .. n c, e l i T-. a t :: lev t c..t) '1
:...-.. t .e a s.'. ] -,f rp :-,- a a inc '-ie. of at,:-c: o ,ly -a feew


S01 ID 7t1L







10 ." 3'ITTAL ITTACA ."T- -o. L510


degrees above the .all, and the arl r lift coefficients
-otainable .M..t be o-.nly sli, tly eater- than those
r..rese-ted. by the lo'er cdashed curve of fi-.cre Tail
b'-ffetf l a-lso li 7ely to occur en the flov: sept rates
.frv:: te .In., co that pilotin- technique cannot be over-
loo-ked &a a possible deter mi;nin factor. fly, at very
hih .a! numbers it is possible that actual instability-
S nountee, in which case hiih angles of attack
'- h lift. iht bO obtained inadvertently ra t Eless


Sgan.isoe oad tir.-b-aution.- Spanx:ise 1oadC .diztri-
tbutin c r ve-s for- ri r of vale of in c nor-:a>l-force
coufficient :4id ,ac; rii cr are uhonn in fi'ne 10. As
I etiond previously- te pri ipal e "ect of the sm....o
1s ruts (wh ich i F to -incr ase the effective 'trear- velociz;)
was acc d for cal. atin el .t the struts
installe, _he 0oc efot of t-e :truts is to rede.uce
tie .lit.. at a ien anlte f atta- a all amount and
to vrod:cre a -.-liht cisuortiaon n the span loadin 'hi_
..",tion .ay b-e seen a- a dip in the curve s of pfi u re 10
near the spanvise station X- = 0.65. The 4 lzd and
O/.-
dashed curves of fiur 10 r ...resent the Coad istrit.i ons
before and after theI stall, repec -ivelT.

It'he c::rve- of figure 11 s:--a.i-e the changes in span
loa liP g cT.b -ore ?'-uad to occ zr ; tie hi-her- te'p t sceed-
9To s niicant chan c in the ---an loading were found to
oc"ur belo-'' the stall at any of the rpead of tIhe test,
ev..-:n .hen 1h aes eere 'll established over the center
part of the. -ig. Change in the 3'an loadinv were
observed to tl:e pla o e bve he high-speed stll, however,
the center of load beino lifted outboard, f-_: e -.-.'.-i
at the .. .her L. e -s were fou;li to be me..ate. The
largest corresponding increase in ending o'ent at the
root (for constant lift) was found to be about 10 percent
at a 7ach nuLr r of 0.55 ac a w ing normal-fo'rce coefficie.t
of aboht C.95. The chan-es in load i tribution due to
stalling at low speeds 1 ere somewhat lar e r than those at
hih s ...-: but ar not of particular si ificance because
the total lift cannot be -fai ntaitnd beyond the stall.

A comrpearison- of the exper--:entally determined load
distribution curves at I = 0.i0 with those 1clculted.
by the r-ethod of reference 8 is shown in fi.---e 12 for
values of wing normal-force coefficient of 0 and 1.0.


CO3it .- .-A.L









..CA ACR i"o. LEG10 C:)ITT F ITIAL 11


.-.e ,---ze *:.ent -h- 7 r, i" t 1--. '- U" at e?:i.-L-[ r i.r the
u. -"t -I c' -,- t o' hie -i-t ,urve ..





n L. -t u .-'. f- st.- of a t:-e._.. .; -' "' .-. -.ries
-t i .-,.- L...
. i t :7. r T



re ._- _," -,-: ~, .e C, : _: .
a 1- t .X -. 't .- t c".'; t c re- .: e a
-,C- R ..I 9. .e t ,
tuE "R n i. t'. v "*:'- ,i.v.w v u .. '. 2,_ ,-,J -.-:..- c ,;" ; v-< _


i^'...1 !' f l-c ; ,'_ :_. .-r. ot ... :i t, z .- .-,,r-,- T ,-.,-' o t. t .e


Ot '.;f-E .- : t i -" .-.t r.ir.. ..l


.- t -..-': c c..i 'e.e .f, _i C t
at uP- i._' .. e *'r.:'- .'! -Ift i U; -.. '" e; '. *. e' ac -.e t at,"-
r*.i,;-. r t ... .- ...'.?t L._e .r'-, e. A.t
" .i. '. -. e t i : L the
n xi-:, : ?. t c ef 'i t ".:-- t -- .. 'J' to 12 i..-:.onci-
t}e' 'rle at .-.. .e ,r I. ) ...i'i. s dll .

.C.. ., c : _.:r
occurred ..e l:'- t).-A1 .?.t& l.t'-- '- f 2,- : te sct,,.

,. .-er ..tc c -:,a:-. ,.:.
cccarre- d ". ~":aXTle.d t "- _-. ,ec,. -Icr
1of "-y '-itI" r- t ,..* .f. ..- oc i:'.ir
in '-: a.:9 i in *':* : :.':. at ''" :. 1 i c t-', -, 1'-"


*,:c7FTL'ET-, 'T- L







12 CONFIDENTIAL HACA ACR No. L5G10


lift ,as about 10 percent and occurred at a T'.ach number
of 0.55 aind. ot a vi:ing norrial-force cbefficient of about
C.95.


Lsrigley T;ieror.ial Aerornautical Laboratory
National Advisory Comraittee for Aeronautics
Langley Field, !:a.


C C' Li7 L --AL









NACA ACR No. L5GIO


REFEREICES


1. ?use, Thoiss C.; S:.m Lffects of Reynoldt and iBach
.iurb.e-rs .n thc Lift of an JACA C01i2 Rectangular
.jinc in- e tne i.CA Ir.-Foc Pressure Tunnel.
CA, C.' Uo. L529, 1?h3.

2. Cl.arH-, Harol. E.: ffeec s of Compressioillty on
cA-XimUIr E i Lf't Co' ef ic e'-ts for Six Fr-.pc 1ler
Airfoils. 1 JACA .S.C Co. L L21a, 19a .

. Rhoide, iichari V.: 'Correl.ti'n of Fii'-t Data on
Limit -Fressur CoefficiEnts ani. T'hir Rfatj.cn to
High-tp.,i d PurE4bli *-d C critical fail Losad.
.iC-&: j no. *L I2 1 12.

.. Iisscn, Jar.:e' ;'., a.d G.leL.erg., Eurnett L.: Effect
of vac:h ar- -I' ir o ldS :ui.imbar's on thre Fowc-r-COf f
iiaximru.i Lift Coeicirt Obtainaole *:,n I F-.1-1
airplanee as Dttetmlined in Flit. ;AC t. A A ,o. 4LF28,


5. Goldstein, S., 'nd Yowuns, A. D.. The Linepr- Pertur-
bation Theory of Compress ible Flw, with Ap'pli-
cations to Wind-Trunnl Interference. i. F. io. 1909,
Britich A.A.C., 1903.

6. Lotz, IrmganrJ Cor'rc tiDn of Dovmirnsh in indJ1
Tunnels of Circzlcr' and Elliptic Sections.
,AGCA Ti. -1o. ,ol, 1956.

7. Tho-;i, A.. Bloekace Cor-'ectio'ns an-d Ch:.ng. in the
.A.E. Hi h S .ed T-uan, l. ep. 'c'. AEro 1C;1,
British n. .e., U.
,. Anon.: *Spa nws e .ir-Load Liscrio'icion, AGC-1(1),
Army-AIavy-C oirme:rce Co:..i c oin -:ircraftt FHequire-
mernts. U. n. Govt. Printing O f.ce, pril 1958.


CONFIDENTIAL


COIFIDEI-TIAL






NACA ACR No. L5GlO


000
cn car 42 "e











3 zyz
(j j
I I
I I I




2 1
a z_1 y __ *\ V -
- .7 -70
o -
fe --- -^-^- ^ -- _:^ 3 0
?\ ^ ^ ^r u
NH -- ^ -- Co '*







1'^~ *U)
l \-\ ^ -^ i A i
^ V^q r
^ i, i i ; r i Z





\ ^^ '?{


Fig. 1








NACA ACR No. L5G10 Fig.. 2











44.
0












CE


K.o

oD
YA~o4
Cl,
., ",a o t













4 0
CE

.- 0c
0 .







'a
0i;. ,

-O'a
.Z.:.. "Q'














EO













Cl Z
I,










ba
*r4 Cv



C.4
... ., C




S- t .-.; -4 --








NACA ACR No. L5G10 Fig. 3















_0
C.-'










I.-I


















0
EE
bn.





OC



E





00
OJ4

.z o
C.c






NACA ACR No. L5G10






8x /0o


7


6"






4
-Q )




rz
W


2


/


0


/f1ach number, Al

F-/u.re 4.- Vacria,'iorn of average Reynolds .n'm7ber
with Mach number.
S= x2.0 f e -f.


Fig. 4


CONFIDENTIAL

NATONL DVSOY---

____ __CMIE FOARNUI









_/ __ __ __ __ __ OMTTEFBAEO/TC

/ CNFDENIA


.3 4


.5 .6









NACA ACR No. L5G10 Fig. 5


























co




)



D4
-*
mU2





























bo
o
0~ 0

















0

.)
C.)




0








00
I-I




bD

















-4*
C.0








NACA ACR No. L5G10


o .' .2 3 .4 .5 .6 .7 (*cr io = C )
,21
2 -& -4 C 4 5 ,2 20 mo ^ = .21



CONFIDENTIAL

F Cgure 6 Lv ;, cre .-* .*;: b- -r C a-.le c-.c-
ar'e "-act' u- qier.


Fig. 6








NACA ACR No. L5G1O


.2 .3 .4 .5 .6 7 -.= ,I


-.2 -8 -4


0 4 8
Lx 'eq


2 .'C 2.0 ( cr 'v=.2 )


Fure 7- cacrc et as a nc.c anacie r a.tack
arnd Macn rJrnoDer.


Fig. 7






NACA ACR No.. L5G10


1.6



1.4



1.Z


CONFIDENTIAL






_________ \ /Vaximu.m l'iff
SF coefficient




Lift czeffic t \ e-t
obtained a.t 2 ,o o30
above the an/e of \
cz/fack oat which
r/n//al .sebaraticrn of
the flow fromr7 the
wIny occurred
(see f/,. 97)







NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS

CONFIDENTIAL


Fi/oyre 6. -


Var/at/on of winy mrncx/munrm /ift
coefficient with /V1ac7h number.


CL mTax


Fig. 8







NACA ACR.No. L5G10


CONFIDENTIAL I




_. SO -- /. : O ,
'








.65------^-


70 ..7

















NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS
CONFIDENTIAL


-/Z2 -8 -4


o 4
d~q


F/qure q- Variaton of wi lq ,f cfefficie 't witn ae
of atracK for several/ Mctch rnmbers..


,'2 .'6


Fig. 9







NACA ACR No.. L5G10











.6 -0-=- ---

0




0




0 __ __





E l I I-- -- -- --










.6

a0
.s J


Fig. 10a,b


Frac t/on? of semispan -
(b) M -0.40. NATIONAL ADVISORY
COMMITTEE FOA AERONAUTICS
CONFIDENTIAL
Figure /0. Spanwlvse /oad dislritfon curves for several/ values
of winq .rjoria/l-force coe ff.,cient a d /lacr. w.va, cr.








NACA ACR No. L5G10O




/..*_ __



--




S.6

U ----

*J















.82~
U
o







0 ./

<,2















0 .
-41
O^

OJ -- -- -


Fig. 10c,d


CONFIDENTIAL


Fract,ion of sem/nspan, y

(c) M-=0.50.


.F/gur. /O0- Confql,'wed.


Fraction of semispan.,

(d) W = 0. 55. NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS

CONFIDENTIAL







NACA ACR,No. L5G10


CONFIDENTIAL


Fraction of semispan, -l
(e)1 = 0.60.


Fracti/on of semispan


(f) M=o.625.

CONFIDENTIAL.


NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS


F/u we /0. Cont/nued


Fig. lOe,f







NACA ACR No. L5G0~.


Fract/iol of 6emispan ,
(9) M=0.65.


Figure /O. Concluded.


Froctlon of 'em/lpon -
(h) = C. 7. NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS
CONFIDENTIAL


Fig. lOg,h







NACA ACR No. L5G10


. c / ./t opt'Q7


I/ 1 >
0 z





*| z







~L)

O'
ON^

00



SQ$
$- '- <
"r ^ )



lb^

K)0


Fig. 11







NACA ACR No. L5G10


sq u '4uapypoo poo 7
4 IT N


-I
N-.



















U


-J



0
O
^|


Fig. 12







UNIVERSITY OF FLORIDA

3 1262 08104 973 5




UNIVERSITY OF FL.RiDA
DOCULIMETS DEPART',EN'T
120 MARSTON SC;EwCE UJsp-Y
RO. BOX 117011
GAINESVILLE, FL 32611-7011 USA