Flight investigation of boundary-layer transition and profile drag of an experimental low-drag wing installed on a fight...

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Material Information

Title:
Flight investigation of boundary-layer transition and profile drag of an experimental low-drag wing installed on a fighter-type airplane
Alternate Title:
NACA wartime reports
Physical Description:
19, 14 p. : ill. ; 28 cm.
Language:
English
Creator:
Zalovcik, John A
Skoog, Richard B
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:
Airplanes -- Control surfaces   ( lcsh )
Aerofoils   ( lcsh )
Aerodynamics -- Research   ( lcsh )
Genre:
federal government publication   ( marcgt )
bibliography   ( marcgt )
technical report   ( marcgt )
non-fiction   ( marcgt )

Notes

Summary:
A boundary-layer-transition and profile-drag investigation was conducted in flight by the National Advisory Committee for Aeronautics on an experimental low-drag wing installed on a P-47 airplane designated the XP-47F and supplied by the Army Air Forces. The wing incorporates airfoil section that vary from an NACA 66(215)-1(16.5), a = 1.0 at the plane of symmetry to an NACA 67(115)-213, a = 0.7 at the tip. The surface of the wing as constructed was found to have such a degree of waviness that it had to be refinished in order to obtain the performance generally expected of low-drag airfoils. Measurements were made at a section outside the propeller slipstream with smooth and with standard camouflage surfaces and on the upper surface of a section in the propeller slipstream with the surface smoothed. Tests were made in normal flight - that is, in level flight and in shallow dives - at indicated airspeeds ranging from about 150 to 300 miles per hour and in steady turns at 300 miles per hour with normal acceleration from 2g to 4g. These speed and acceleration limits were imposed by structural considerations. The tests in normal flight covered a range of section lift coefficient from about 0.58 to 0.15, of Reynolds number from about 9 x 10⁶ to 18 x 10⁶, and of Mach number from about 0.27 to 0.53. In the tests in turns at 300 miles per hour, the range of section lift coefficient was extended to 0.63.
Bibliography:
Includes bibliographic references (p. 18).
Statement of Responsibility:
by John A. Zalovcik and Richard B. Skoog.
General Note:
"Report no. L-94."
General Note:
"Originally issued April 1945 as Advance Confidential Report L5C08a."
General Note:
"Report date April 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 - 003613553
oclc - 71223743
sobekcm - AA00006282_00001
System ID:
AA00006282:00001

Full Text


ACR No. L5CO8a


NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS





WAlRTlIME REPORT
ORIGINALLY ISSUED
April 1945 as
Advance Confidential Report L5C08a

FLIGHT INVESTIGATION OF BOUNDARY-LAYER TRANSITION
AND PROFILE DRAG OF AN E~ PERIMITAL LW-IRAG
WVIG INSTALLED ON A FICGUER-TYPE AIRPLANE
By John A. Zalovcik and Richard B. Skoog

Langley Memorial Aeronautical Laboratory
Langley Field, Va.


MNACA
i .. *


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


:c`


L 94






































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/flightestigat001ang








NACA ACR Ho. L5CO8a

TIATIONAL ADVISORY COMMlIITTEE FOR AEROrAUTICS


ADVANCE CONF1IDEITIAL REPORT


FLIGHT INVESTIGATIONS OF BOUn A:RY-LAYET"L '"A!ITIO.'

A?'D PROFILE PRAG OF A7 EXPZ. TP i'iTL .L.-D..

ITNTG INSTALLED 0 A I GHrR -TYP ..RI'T r.'E

By John A. Zalovcik and lichard B. Skoog


STh V.'.R Y


A boundary-l'er-tr-:. tr ition and ni',efile-drag investi-
.ation was conducted In flight ." the Ja tion'." visory
Corrtmittee for Ae-onautics oi ,n .-n x.:e'mrim-ntal low-d'rag wing
installed on a P-47 airplane designated the :XP-'47 anrid
sur.nled by the Ar:my Air Fo.rc'es. The win1 iricorn.jr ates
airfoil sections that vary i'from an U.4Ca L'-(315 )-i(16.5;,
a = 1.0 at the lane of sa; ,ietryL to cia i ACL 67( 11)-215,
a = 0.7 at the tip. The surface of tiP 'vin;: as con-
structed was found to have si:rh a degree of ,iAvin.3ss hat
it had to be refinished in orter to obtain tie rnrfcrmance
generally e;:xected of ow-drag airfoils. i;:-a surer.if nt'i
were made at a section outside the propeller s lipstream
with smooth and with standard camouflage surfaces and on
the upper surface of a section in t-he oroneller slip-
sti:eam with che surface smoothed.

Tests were ,nqde in normal flight that is, in level
flight and in shallow dives at Incicated sir-sp.eeds
ranging from about 150 to 500 miles cer hour and in steady
turns at 500 miles per hour with normal accelerations from
2g to 4g. Those seed and acceleration limits were
innosed by. structural considerations. The tests in normal
flight covered a range of section lift coefficient from
about O.5d to 0.15, of Reynolds number from about 9 x 106
to 18 x 100, and of Mach n'.unber from about 0.27 to 0.53.
In the tests in turns at 500 j.iles ner hour, the range of
section lift coefficient was extended to 0.6.3
The results for the section with s'.ooth surface out-
side the slipstream were in reasonable accord viith the per-
formance expected of low-drag -irfoils and indicated a
minimum Drofile-drag coeffic,. nt of 0.0145, which corre-
soonded to the most rearward position of transition
observed at about 50 recent of the chord on the unper










NACA AR No. L5C08a


surface. With a standard 2'.ish, a minimum profile-,'i..
oefficient of 0.0063 was obtained. T-.: results obtained
in turns wil- the smooth surface showed an increase of
about 6 to l4 percent in the profile-drag coefficient
above that obtained in normal flight at lower ,-,c
numbers and corresponding lift coefficients; whereas,
with the standard finish, no increase was observed.

The results on the smooth uoner surface of the w!n-
section in the slirstream indicated that, with normal
engine operation, the most rearward position of transition
was between 20 and 25 percent chord. The attempt to
measure th nrofile drag of the smooth '.--r surface by
means of a half-wake trailing-ed!e rake was not successful !
because a large lateral component of boundary-layer flow
existed at the trailin; ed>,- of this section.


INTRODUCTI .r


An invest'" -tion of boundary-layer transition and
profile drag of an experimental Icw-dri,- -.>;.: installed
on a P-b7 airplane designated the XP-L7F and su.rlied
by the Ari.a Air Frrces is renortpd herein. T.hi s win
incor-orates airfoil sections that vary from an
-ACA 66(215)-l(16.5), a = 1.0 at the plane of symmetry
to an NACA 67(115)-212, a = 0.7 at the tip and is the
type used on several current airlane desl 'ns.

An investi-.tion of the aerod--namic .-rformance of
the complete air. l-.e was not undertaken because the
surface of the w1in2, as constructed, was found to have
such a degree of waviness that extensive laminar boundary
layers could not be expected. T!he results of performance
tests of the c-.rn:lete ir l.~.e, therefore, would have ?ad
no particular s'lnificance in evaluation. the merits o.'
low-dri a w'nrs havi.n: surfaces that conform closely to
the requirements for extensive laminar bc ni-sarv layers.
The invest':- tion was consequently lli: to the stu'y,
of ooundary-laver transition and profile drag of sect"'cns
of the ni4 *, with the surfaces in the ori in wavy cr-.-
aitlon and also with the surfaces refinis.:e. to reduce
the waviness to tolerable limits.

previous fl ht invest tions of low-dr-; airfoils
have been concerned entirely with the determination of
boundary-layer and profile-dr.ig characteristics of


CO NF IDE NT I.'. L


CCF IL'IL TIAL









NAIA F' o. L50L3Ja
Ldttj /4.CI J%. S*


C ONF IDINT TAL


sections located outside t:.e roreller slipstream; hence,
no information is available on ch.e znc.racteris'ics of
such airfolls located in the po.'o:eller slipstresa-, wl.ich
may .*.over': 0 cspcent ori n, roe of th"e w.'iin. arees do-icnrein,
on che type of airp.lane. B3ond.ry-1 ler--tro.scic and
profil. e-d's,:g tests aer'e co:'sequ.-ntly idL.de at tvwo sr-anwise
stations of the low-drag win6 of the ::F-1F airh'luin -
one o.,tside the propeller slipscr'ea:n :.i'd one behind the
propeller to Jeter-iLrne c.he e::tent to which lo.:;-'l'
airfoil charact-eristics iae" be obtained in th -se t.w
reg' ies of :.ir flow nith cthe surfaces of -1,e win- care-
fully finished, 'assuremeniets on the winz section in the
propeller slirstre-a' '..ere l'-.itie to tl-. s3nootih:d unper
surface bec&' se iri'reul r' t'es on t'e l:a.'er surface Jue
to tht- landing-gear -over co,' 1 .-:iot b1. fai-.ed. -' st
%.,wer also iade of ia sccion outsi he s lip3tre-am on
the n'oboduticn surfaic s with a stun'jr;lr c..aroufla e
finish.

[:e were !iade In level flight nrid in sh9ialo. dives over L
ran.e of iiicate'- d airs peeA fro-i a&'bo t 155 to $10 miles
per hour. I'easurements on Lth sectl-.n outs 'e the :pO-
poller slipstream.- ware made in level flight anrJ In
shallow dJi"s3 ovr a --.n-e of in'li c--; airsraeed fro",
about 150 to 5j30 riles per hcur .nd in zt.e:ad" ti.rns at
500 miles r.er hour 'ath nor:;',l accelerations from 2g
to 4a to obtain high wing loads. 3c:..e i.icasu.'enii3nts
were made on both of these sections in glides wIth the
nine throttled. The sceed and c.ccieraLtioo li...it3
observed in the tests were impoJs-d by structural con-
siderations of the airplane.


S' DOLS


c section chord

x distance alone; chord from lea-linr edge

s distance along surface from leading Cedg

d deflection of curvature sgae

q -Fimpact rressiuro In JoLLnd.ar: la,.-r at 0.006 inch
1 above surface


CC:'FILEiTILAL









NACA ACR Pro. L5,O8a


qc impact pressure outside boundary: la 'er

cL section lift coefficient

c-, section prof il-drag coefficient

P pressure coefficient

Vi correct service i.nicated air,-el1; that is, the
s correct reading of an airize-ed indicator cali-
brated in accordance with Army und Navy
st an .i- rds

R section Reynolds number

S 7iach number

:cr critical IcIach number
cr

g acceleration of .-'.ivity

Subscript:

t transition





The r-:. '-' el- lane tested is a low-w' .., single-
en -r:e ionoolane with a Pratt & '.'..Ltney --20..-21 .i
an:- a four-blade Gurtiss electric p:'.'-3eller (f'.-. 1).
It is equipped with a low-dr ._ vi:... the i.iaster airfoil
sections of whir are XAJ. 6 1215)-l(16.5), a = 1.0 at
the -lane of s- -r:- and .-.,A 67(115)-_-, a = 0.7 at
the wing tip. The airplane has a -. oss wel "t of about
11,630 pounds, a wing s-:.J. of feet, and a 'lrg area of
522 -.:uare feet.

'. sections of the low-dra: wing were tes'_i one
on te right wi:.,- located 1 inches out-.:ard of the flap
and the other on ti1l left ':;- located 1 Inches .:-thin
the edge of thi nropeller isk (fig. 2). ': r.l t
wl..2: section had a chord of 83.5 inc. es and a ..:'..
thickness of .7 percent t L 45 percent of the -'-".,r.
T. ordinates of the ri_-.t win section measuredd relative
to an arbitrary chord are given in table I. The le't.
wing section b-!.i.-.. the propeller had a Ln.-:- of


CONFIDENTIAL


CO*: :" ..L









NACA 'CR 7%. L5C00a C1TErDEr '" TAL 5


103.5 inc1fls aind a :naxiTaL:m thic.:ness of 15.c nerocent at
45 ',erc.it of th.e cnrorc.

Tfvo surface cod-i'tio.is of tie w',ht ,inC section
and one of the left -nr,. section were tested the
ri, .t wing section ailth t-hi s.:rfaces h-vi.- s.,m.th ::nd
stand:-rd car.:.ouf.age finishes; tlh uoper surface Cf C-.
left wving section with only the cs:-oth finish.

The 3ricthrCe andd fai'e-d sa3r.;e43. were r(btaIaned by
building up with glazing .nutt: ':t .'- oas3e provided by the
refi'i sEhin".R do.le on a:!-e ,in; at .t. ,A\ir ',cltnica1 Se v'ice
?oa"n.rd, .'rig-ht i 'i ld, a.-j' e" n lndIn; to reduce the
surfa-e wav'aij r''! surf :e- we'c theen s ru .-cd "ith
Court coats of white 7.acqu r as a rr:t ". tit.. coating and
sanded light tl Surface :9.3.viness was e3asure.d 'y d
c.-rvat.-re- g". ( fi g)ei h (.l~s s a ced '4 CrFert of
the I:Pc rd. The vWevinels3 c.-. '-,C 'lon 0- of d.:.- final mcm otl-ed
surfaces Is rin'catdr iin : ur-3a r. d 5 '-r th, p-lot of the
wavrine.ss incex d/,c against 3,. h V1.aues 3 d,/c
incl' id t..:'. c.,rvature cf -irfoil suri'ce 3 free '..'
waviness as v. el as the .enart.:w, of '- sictual surfaces
from .: wavinas.-fre:- contour.

iAfter como'.etion of the t 't, of t:' s;..coth ri 1.c
win;- section, c .e o~saLt and lazin;-g iui..tr' crn tals se tion
vwere removed to the metal sl:in '.vitr acet .-,: andJ a
standard Camrouf.l2ge I nrish was t' er, a3ppl cd. The
standard ca::.ou:'luge i'nish cc.-s'st ed of o.e coat of zinc
chror:iate primer, one coat of 7r r s3u- f ace..', and t-;wo
coats of olive-irab cLno~ 'a e1. "be surface .ith r.is
standard cm.o iflage finish is 'ereliafter c.esignated
"standard surface." The surfe-.a'.; -.ess inde:-: r Lhis
surface condition is show., in fiur: 6.

Boundary-layer racks, eauh consisting 'if a -ota l-
press.ure and a static-rresjure- Ltbe, .:';re used in
measuring boundary-la:,rer transiLion. TL-e tutes v.ere
made of --inch brass tubing with ---'nch wvall thickness.
d 52
The u-ttream end of ,-'.e total-tress .ire t'.f-e was filed and
1
flattened leaving- an open;.in 0.-3., InCh .1fe? .e and 7 i:,ch
wide and a C0.cjuS-jnch wall thicc'-s.j. The stat c-c.ressure
tube had six orifices 0.02 Incl in diar.ieter equill.y spaced
aro',id the r.eriphler;. at 1- inches downstream fr.rm the

CON7 IL TTiAL









NACA ACR io. L5CO3a


hemisrherical end. The effective pressure center of
the total-pressure tube in contact with a surface was
at approximately 0.006 inch from the surface. The
total-oressure tube was connected to an NACA recording
manometer and referenced to the static pressure obtained
1
rc : the static-pressure tube set about inch from the
surface to measure the impact pressure next to the sur-
face. The static pressure measured by the static-
pressure tn(,c was referenced to fro7-e-strea total pressure
-i-v'. the I.pact pressure outside the boundary layer.

":e surveys were made on the ria'ht ;n'ir; section by
the rake shown in figure 7 mounted !-.1 percent of tCi
chord behind the trailing edge. The rake consisted of
24. total-pressure tubes spaced 0.3 inch and five static-
pressure tubes spaced equally across the rake. -he
total-pressure tubes were connected to an U..A.i recording
manometer and referenced to free-stream total pressure
in order that the total-pressure loss at each noint in
the wake could be obtained. r'.e static pressure in the
wake was measured with the central static-pressure tube,
which was connected to the manometer, and referenced to
the static pressure obtained by means of a swiveling
static-oprssure head mounted on a boom 1 chc're ahead of
the leading edj: of the right wing tip.

A half-wake trailing-ed_" rake (fil. 8) was used in
an attempt to measure the profile drag of the upper sur-
face of the left wl.:- section. A full-wake rake, such
as described in the nreceding paragraph, was not used
because surface irregularities on the lower surface due
to the lIr-.,din.-gear cover could not be faired. The
trailing-e,-I,-e rake consisted of 21 total-oressure tubes
1
seaiced about inch and three static-pressure tubes.
-. total-pressure tubes were connected to an .-CA
recording manometer and reirrenced to slipstream total
pressure as measured by the rake total-pressure tube
5 inches above the surface. The slipstream total pros-
sure was referenced to free-stream total pressuree givin.J
the total-pressure component due to thrust in the survey
plane. The static :r..ssure in bhe wake was measured by
a static-pressure tube inch above the s'-rface; this
tube was connected to the manometer and referenced to
the static pressure measured b; the swivel':.; static-
pressure head.


CC.'':D TRIALL


CONFIDENTIAL










I .'tC.h /.CR Lo. LCCOSa


j'c'ol tuf'ts v.e'-e used con the urt.' r surfac c of the
ript and: left ',in. :ectioins o-ler che trailing -e-dce area
to d"et.erminre iih-th:-r any cross flo.. thait .cul- inv. validate
th-e ',aIe surveys existed in tiic bcundary iaer. Chalk
11., .t irn- ,icacing an 1ular devise L-n J om the tliru::.t axis
of C', 100, 20, anQd 50)0 J'er ,,arkdi.cl ci't in the
re" -or: cf each of1 two tufts located ,; &nd a1 f et, res _'rc-
tiv-';-, on cea-!- side of' tile f'jselar -, arnd ab jut .10 inches
fro.: the trailing ed;-e (fi.. 2 J t.:' .rC .l t:.e .:lob to
ju.d-. the ar.,-.larit y cf the tu. t-s .ac thcs:- :'olnr .

All :nreCs ur s .:.'re r-eccor.J- o:n :-.CA reco---di.i
ins .'ru.ents Tie position of the ,aii..r'ons duLLirp th-.
tests was recorded -,n an :TI.CA control-i position recoorder.
An in'ilat.ng acc-I l.: rc.rr,' r n 's auze tc in icate normal
acs :el' rat ions.


:'~! I,(7


In o-,-c.r to ojt3 ir fr-c -z .:'.-an c : t re supz ,
corrctti-ons detFrm-rincd fro-L: a&n air :- ed P- ? iitr.atlon
were e to e t to the sti li C sure i.:-:3 'ure'? 1 th; lic
swi,,/elin- stacL ic-pr :-rure head r-uJ.ncerI on a bc.-r ahead
of the ri- -t w:lrn- ti These ccr '- ct ions '. :r a-lled
to ill :ne.. ur.r ent for .vh I r-Ifep re c, t free-stream
state T- rn': su.r' v.-as r-,r- u.l e .

TI-e section lift. coef'i- .ie-.t at wlhic tr::ns tion
occurred ?t a &c given chorxdwise -Co-Etion vwas determined
fro..i the boundary-layer mes.ou ,.'-,-:;nt of iro act pr's-
sure qc at 0.006j inich above th: surface and the i.iact
pra urt qc, outside th.- bounriodary la-er. The-:

rat-i --- 'was rnlot.:ed a inst s ectior- lilt coefficient
c2
as determined from airplane lift cc&-fic-r--nt and: theo-
retical sranwise lift distribution c-y the :',thoio of
r. f'.er- ce 1. 'Thoe section lift coe'j -:cient corr-sr-onlding
to transition -ras chorcn ati th'-e L].'.'. cf rI- c'u-':. as
q1
the ratio -- suddenl-n inc!-?.':.:.'... "'r '? its la.ini,-r level
q02
to its tu-t'-lent level. In tih.: .1r:isit ilon :.; :sureC: Gnts on
the -vi.n section in ti-.e p'ti',:l1'r- sli.ps -: ai, the measured
qc2 was corrected to slinetr-a': -..,:itions by ad-dji


C 0 1TIDEr"T AL


COr "'TD '.TT .' L










TACA ACR .ro. L5C03a


to it the increment of total pressure due to propeller
thrust in the survey plane.

The profile-drag coefficients were determine. by
the int', :rating method of reference 2; that is, the
total-.-_, ssurc loss was integrated across the wake and
th-en m-lti'plied or factors der-ending on free-stream
impact pressure, maximum total-pressure loss, static
pressure in the wake, and flight iach number. For the
wake surveys on the section in the slipstream, the field
of flow was assumed to consist of free-stream static
pressure and of total pressure increased by the increment
of total pressure due to thrust of the propeller in the
survey plane.





?Tr-nsition measurements were made at 20, 30, .O,
ans )08 percent of the chord on the smc,-th upper surface
of the right wing section and at 5, 10, 15, 20, and
25 percent on the smooth upner surface of the left w ing
section. Wake surveys were made on the smooth right
wing section and on the smooth up'-cr surface of the left
i..- section. Lake surveys were also made on the right
wing section with standard surfaces.

rnr.sition tests of the smooth u:.er surface of
the right wing section were made in normal flight; that
is, in level flight and in shallow dives, when necessary
to attain the higher speeds, over an indicated-airspeed
r-r.n.-e from about 180 to 300 miles per hour. Some of the
tests were made with power off, that is, with engine
throttled; others, in stead-: turns at an indicatAed
airspeed of 500 miless per hour and normal accelerations
of 2g and 4g.

Tr.-.rition tests of the smooth upper surface of the
left wirr- section in the slipstream were made in normal
flight over a ran:e of indicated airsp,=d from about
155 to 510 m-iles per hour. A fe-i test runs were also
made ;with power off.

,.ake surveys on thc right wi:.' section with snrcoth
m!d standard finishes were made in normal flight within
a range of indicated airs. e:d fro.- about 150 to 510 miles


CC'" I'T ITAL


C rtTI E D 'IAL










F :rA AC? "o. LcCO.:Sa


per h;cur Ci'nd in steaOy 'ur.1.n. at an indic -teld alrsrs'ed -cf
a':iout CO r:.il's er }.our erJd ':'r.-.si ac e lerat ,ens v":'c:n
2, to So..ie of trhe 'test ..ns on the ci.cot: v: in: fe:-
tijon "ere n.ade v,it. pcw w off.

.j&::': suf,'r l s o t e s...OOLh. L'L I s C.3 oC th t
wV'L-; cs cticr, '-.Lre ni-de in nctt."r.1 f' .l' -t r ,e-- -n in.-1c1La:d-
aircr.csd i ana f'ro c'bou 1a: to I1 .. ils er.- 'r-C A
f~, test ri.n '.' cre made *-:itin ,-.'. o- f .


PR:.S",-ATI:l o HISUI'ST


Th.-- res,.ults of t.hei i'" on: e p S-S nt d in
fi7'Lr .' to 1 ] mie p1c:-sur: di. r-ibul ior. r the.
sIonth r"- ht :-'inpe ,Ltion is ri;'.e; fi-i re '. The
t,-'i orc t i '1 o r ersu:'-, flic tr i ".i.' on ."s *:-.c li lated Trom
t'i? or:1.in et1 s ri t ; e. n 'n L e I L I T' rI: r-
en-e 5.

Tr.nstl i t n r ciul tz o'ta I: he rt' ont!': 1rnjrr sur-
face o l et r1 right i.pr ecti ,! ..;r: rc'tc r ifc .'res 10
and 11. Tn f ir'ure "iC, -The 'j, li'"tr -f ent chosen
a~ cc'r srcr nd.lrre to .ransi :. t i :t r *-i:ri cT. ,'::(;i .. .-
tijrn i i .rdicsted b-- :n _rrow a t" e el'b o'." ? rf c..?.


qJ) a
q~e
-- -c.vr've. ?he TLcili s n'.!.:cl "s c, i lE ?-'i,,; i~' tD t eI'le

s&-tica,. lift coefficents of t.'.e ----cuv.rs cr olrttel
q. 4c2
above the ----curves. The var -i r.ilc of th-l .)csition of
Ic2
transition. wNith section if t *..':ficient is shown in
fi.-gur-e 11; the ePa-;.olds nv.rnmzoi c .riE s ., nc in-Z to t:-.e
section lift cosffi lent. s .E _i. ltted 'ove tih tr.nsi-
tlon curve.

The variation of n-rDfil:-drra-c cieficient 'ith sep-
tion lift coe'f'ici nt for tn- rii lt *;an.1 sec.rcior. with
s.nooth and starda d fjnishas i.. c: Lcnclcd for ncrrnail
fliIht in fig-ure 12 and fcr iAi. h-s.,-:ec d turns in fiEire 15.

Transition re-ults ottained o, the rr.iooth li;oo1' sur-
fac.s of the left '.irr s'ctioin in tr-- sElii]-streama arn pre-
sented in figures 11.. and 1C,.


C -.. T ~, ,TAL


C'".IDEPT-AL









NACA ACT 7o. L5C08a


During the tests of the right win- section, it was
10
found that the right aileron trimmed up from to 1 in
normal flight and from 10 to 20 in high-spi.3e turns.
Corrections for these aileron deflections have been made
to the section lift coefficient for the right wrin sec-
tion computed by the method of reference 1.

DISCUSSION 0- RESULTS

Right Wing Section outside Slipstream

Pressure distribution.- In figure 9 the theoretical
pressure distribution for the right wing section is shown
with a few experimental points deter-ined from the static-
pressure measurements in the bound_..-. -layer-transition
tests. The theoretical pressure distribution for incom-
pressible flow was ccrni'ted for a section lift coefficient
which the right win' section would experience in incom-
pressible flow if it retained the angle of attack it had
in comoressible flow for a section lift coefficient of
0.200 at a Mach number of 0.){6. The section lift coeffi-.
cient for incompressible flow was tallen as c,/l1 z
or 0.177. The theoretical pressure distribution for com-
pressible flow, as determined by dividing the pressures
for incompressible flow by j/I- -2 or 0.887, agreed
closely with the few experimental points obtai-.n *1.

An analysis of the theoretical pressure-distribution
characteristics, computed by the method of rejerence 5
with use of the measured ordinates of the right wing sec-
tion (table I), indicates that the characteristics of this
section may be best approximated by the TACA 66,2-2(14.7)
airfoil section. The mean camber line as determined from
thie measured ordinates of the right wing section cannot
be si'-.:ified by the usual a-designation.

Boundary--layer transition.- Transition from iLa.iinar
to '-'r.:'1. nt i i.. in tih. b'lui.-Aary layer as occurr: ,ig on
the smooth upper surface of the right wing section and as
affected by engine operation and high wing loading is
indicated in figure 10. As the section lift coefficient
decreased, the point of transition moved progressively
rearvard up to and beyond x/c = 0. v'! ich is about
7 percent forward of the calcula'. .i1 iinimnum pres":lrt
point. With further decrease in section lift coefficient,
the point of transition appeared to move fcr':r.m..LJ. as is


TC 7'7TT7T':qL










I-.-,CA AT I'o. L',C',a CO'TF DEiTTTL 11


in', ca ted r-, t" _e .:. er*r'en,'" e ,fr tr Fns it'on from laminar
tro -uri'erit c:v at x = ".' -. .at 0 = 0.16. The
r *a"ri ov:,--rnt o ` tra i t t 'i is tt-'.'v.:t d to the
S'.l s 31C-1...,- 1 .. n: ."r_,nles increasing
air-.!" e s'e- rds ind iiec :r neasini. ic, 1:! ft coefficients.

I s .. i.. t .t, E al O : '. a *'c ..si : erable iin:prove-
":.l t .A.;J e :e ur.,- .. : L.- very careful
ret f .'-.i h'n : 't 1." .t o ,n l f .s. -L .d 6), a still
C.. .."-..--' r '. .; o i.' .' :.. .- iz :._Ve r. i.lted in the
.o--'.. ''it cf '- ~-, .r_- -, t. -:i t ,. ..t 'east up to the
,"M i ": '.' ;, T ; e *.1 1 'T t.

T'i, t. ..: ti n':' r~- .1i3 S t .i i :-'. t:! rower off -
tl At L 3, vi' t '. t: ''tti: 'c.iLe lhat, allowing
f'~r e .' -~-:.- iLl -iror, -. .:'tnc f -= laminar
bo'n' : r- l'-:r :' r :. r o o _.; t: -- t .;, .;. ..re J.ral operation
-i
of t- r.- ie. ( ..o v 3 f .- .-iven lift

officeic '-r t :-*',. 0' ,i. ;:. t: bolr L '.i y-
1--"-r ron...t-'r n .. : '? Otil irs.:,\, next to the
s" rfac.:- \ '.r .:' f, ':, le,,-. to .- .- t. ..-r.) In the
I-..; w' ir- i di1 t i :..., is ,- ,,-,: .,_. rn a ste_.i -
t on at n i ... -t -"c: t. cl ,u.' ,iles r hour >;i,
'A :r-.i- ,i]. i l, r t lr .o .' L j, tr _i..?: 1 -. ,rared to 1.
s t- r :.,-cK: ..-;- -.. .--.- .r .. .' .-ce 3 i : -ior."al flight for

tr sa. i:t ci:..'ffci t (T- '.-alu rf at
q2
:*. -= .11 r ..r t-.e 2, 1: rn is r 'f-sc ]e : -hat is,




7T-,..' "'r'atio'-1 rf :.L -,oir.t :. tr ,,i1 tion with section
1 L: co e!'i, er.t .'s '..e i i. we raisition
an, e-.r -.. .o ean r.' .. 'i c t r-. r-1 ',s t.i ,n at -:,/c = 0.50
or :.-. cit c.Lt ,i' .'-.e c. o 1 2f.cl arli :' o.f the calculated
;-i f .nih L 1 rre s .* r- c t.

FeoY-l ,_ras3 "7 o" ,-",-i fI 'i- t.- Ti-.o rofile--' i a.
co tliTc :r c,'ta. ,- a n,.i I T ,Ti l' t -.n t ri t L i* "
section i tr-. s:r, oo an-d c- i, 3d uf'ar s shown in
f e*r. -2'. 3 '.'.s t-f -'-rve-s .'r :e .,.er surface
n:-ar t"-e tr.i l n-i' c- e of ;., se ci rn 1:-.1 : :ed in,. crosS
flew in i.J'e ~' or'nJain l --:, er, t:F v,.;,: .i:v-ys re v:.lid.
For' t s.ootti .:' ti r r--f ... c -'fficient
Decreased vitl dp-re a3 sini lift :.".' if- -.' :.t ,.,i: i 'rF s As ng


CCILE ',TIAL









12 COC'.T7-'TAL NACA ACR No. L5C08a


spee until a minimum of O.00L5 was obtained at cL = 0.135,
R = 6 x 10 and Vi = 275 miles per hour; with a
-s
further decrease in lift coefficient, there was an
increase in the profile-drag coefficient that corresponded
to the increment in profile-drag coefficient estimated,
according to the method of reference 4, from the noted
forward movement of the rpoint of transition. As may be
expected fr:o, the transition results, no favorable effect
on Drofile drag was observed due to airplane operation
with power off. With the standard surface finish, a
minimum profile-drag coefficient of 0.0063 was obtained
at about cL = 0.22, R = 14.7 x 10, and Vis = 250 miles
pr hour. At the higher lift coefficients, the profile-
drag coefficients of the surface with the standard finish
tended to approach the values obtained on the smooth
surfaces.

Profile drag at high wing loadings.- The profile-
drag coe.fi ci.'r:ls of The iriTh v.in section with smooth
and standard surface finishes, as measured in steady
turns at an incricated airspeed of about 300 miles per
hour, are shown in figure 13. Faired curves representing,
the results obtained in normal flight are included for
comparison. The comparison of the results for the
standard surfaces in turns and in normal flight is
limited to lift coefficients corresepndinr: to 2g and
2.5g turns, because the tests in turns and in normal
flight were conducted over different ranges of lift
coefficient that overlapped from ct = 0.52 to c, = 0.0.
At c, = 0.32 and cL = 0.34, for which a direct com-
parison was possible, the profile-drag coefficients for
the st-aidard surfaces in turns and in normal flight were
about the same. At cL > 0.45, the profile-drag coeffi-
cients of the standard surfaces in turns were about the
same as the profile-drag coefficients of the smooth sur-
faces in normal flight.

T".i profile-drag coefficients of the smooth surfaces
in turns were higher than the profile-drag coefficients
in normal flight throughout the range of lift coefficient
tested; the increase amounted to about 6 percent at
CI = 0.50 aind to about 14 percent at cL = 0.58. The
nrofile-drag coefficients for the smooth surfaces in
turns were lower at lift coefficients less than 0.40
and .r-ater at lift coefficients greater than 0.40
t!an the profile-drag coefficients of the standard


C O" IDr ETTAL









N4CA CI? :o. LCGOOa COFTFDEfrTIAL 13


su'lr- ce3 in cL'.'ns: no 3s t' s af.itorv: r-:-r lanati. 1 n e7f t-,i
rP? sl t, "'l.ich is cc.ntrar''r to : riral ex:',C "l.t' or s, i.:o 3
bt,'e3, fo.' id .

In T! er to lete'r nine hoi'. c1lcsel:,' tle c. ic ji a ..ac
r.1- th 1. .t inT sect i'. n w As a') .' C(.ac'rl=d in t
hi --..'.- G tj:- t:, cri tici L 1'a i rIL -. .; s
stir ,t fr .. rre s.re 1 ist 1 uti e: .. '.'.1 te cor I
s?: ,c '.ift '.c. f [icid-t.t of c7 -,l '- t -., t:e .- thod
of ', f,-Ptr ce '? i, in :"hi.h t-.,e 'e. Si1 -cd o- .'natc s9 of '-h.e
ri :. '.v ini -, s: 't cal e :i ze. in : .h von v-'a r ,ian-
Ts:~ reta.tiDn (r:-cre1,'- 5) j .::e.:rn 'i a.ic static
p -- .', "or in c-) 1 )C I i'l -'-: '. tics ,f :..' fl kht
" *,.. ; n '.t c r'. [ tt "L~I .. -' t l. ,. : ',. '.'-r .1,r t.
fOcr,' l,'u "*d ,rio- n :lc..l ;:,- le:". Lit c.c, s-, '.-r : ..u.-1 in 'h3




i
t-sts are as follo.:s:


'mrmal i .
ac ra'Q on rr r. ". '.r s'-aoth




I ..C ". .. .i
g. u r s



'Th i'suito3 o;.txin. in :'gh-s3r-ed turns ci- rfrre r- ind-
cat.d th-t, ': .r t e i n q' c I t .'s' S::r.f I; .: need
in e re tc--ts, ino in T r asr', ccc-rred in thne -r:' f'i -dru".r,
o- "i '.- c. t f-1T.2 jt n iard s ..iri c s :.bov : t.-..t cnta-ned
in normal Fli1 iL. at r v.- r T,l ::! rnI-'i?' u: :;d coroe-esro lin3
s? I CI'n lift nr,c.f' "en ts (frc ..2 t, 0.3); .'* re s,
f'c '. onth ,nr .es, Ln-re.ses ot 'at-: t 6 '-cr- it. :.t
S _,3CI.0 in. abc-.it ,. ne-rrent :tL cZ = ... wv re bt.blned.


L:ft 'I'.,; SLct Pn inr Pro e1ll1; r s1:. pctr: j1

Found a y-1.a r tran t ion.. Vri i t'. '.. t
sect o- if'I coe F' TT. i -' T '-e r- in. c t':.. 1on on
the smooth un' r lsurf..ce .of tlhe ]e?' w in sect.-:o i.I
the s in3s Lreai --in the ef" t -1" -:itr. T- jtiicr, on
tr'a si tion ar'e chown inr r-'.r:s. 3 !LI. arid 15. '.' tt nor....al


0N T.', 1 I AL









NACA. ACR No. L5C').


engine o-eration, the point t of transition moved rearward
from x/c= 0.05 to x/c = 0.20 as the section lift
coefficient was decreased from about 0.44 to 0.-4. The
most rearward position of transition for tl-e range of
lift coe'ficlent tested la:- between x/c = 0.20 and
x/c = 0.25; however, it is highly "rcbable that, if the
test with the boundary-la-'.r rack located at x/c = 0.25
were extended to slightly lower lift coefficients such
as were experienced in the tests for other chordwise
locations of :he racks, transition .ight have occurred
at x/c = 0.25. .ith the engine throttl.-, transition
at a given lift coefficient occurred a ro. :-,.tely 4 rer-
cent of the chord farther rearward than with nower on.

rr;_'le fra- After the wake survey's on the ur'-ar
surface of' the left wing section in the slipstream were
comnTleted, tuft surveys were made at positions a, b, c,
and d. (See fig. 2.) These surve's have shown that
cross flow in the ubondary layTer existed and was directed
toward the fuselage with an- l,-r deviations (in deg)
from the thrust axis as follows:



Vi-,, position
) l a b c d


Power on

185 d8 20 5 10
255 20 15 5 10
510 20 15 5 10

Power off

185 18 15 5 10
255 18 12 8 10

Because of the cross flow, the wake surve-s on the
u-per surface of the left win1 section in the sli:-jtream
cannot be used to :..-termine the profile-.r-g coe:'cient
of the upper surface of this section. If the presence
of cross flow is i -.ored, however, as it would i-e if
the tuft surveys were not n.ade and there were no reason
to sus-ect tie ". a~urements, the evaluation of the w, ae
surveys by the usual methodss would give on :.*-parent


CONFIDENTIAL










:~A,,CA ACR ITo. L5COa CO?'j'TD'IT IAL 15


nrcfe-:'ra;g cofficier.t of C.i.01:5 .:'th normal er-1ne
oneratioi and O.UC-iO with ergi e. t"'"--jtledi at a c c'ion
lift cc eff1'ci-nt cf abcut U.20 anr -e *,-,l, d nLi.I r of
about 19 x 10 .his cl' if re in ri.e i:.rt r I1r.r -
Jdr' g coefficients as c.bttaned i'.Lr A ,-ral r~ -i.; ce-i-
tion rnd '.;th enlin2 throttled 'would be z:ectod I. .r.
the i ransi ton results, which s'.r.e e jre .r lwa-"
position of transItio-ii v.1th en;lre t.rottle;.

In o"der to obtatnr so e i.:.e a of' e :u rit'.:tue of
l?_e ?refLle-drig coe"ficie:nt to e 3':peto-L. o.1 t'e
ur.rer surface of th left ir.'n secir tL-.e profle-
drag .2oef.'. .c-:ent wus corp'.iedG for a s action lift cocf-
ficient of 0.20.?j d Lu !ke,.-olds nu.'be.r o.f 'i x 10- by-
the method of ref'cre::".e .'. .. by usin .- th nositiCcn of
transition a:.s m"ea:sure cn ,th:e u-.er, surface cf c':- s
section v,.th nonial engine oper nco':. r Ile-..ra
coeff'ci*snts co-m.i':te! '.n t'.'s .anr: er '-:e be- fo'zid
i.n ot:er in,.'estlircati^nns to a&ree r:.at r- '.well a; ti.
pro, ile-drag coe'ficr .nts -ioasur,:d. In ats..ce of cross
flow. 7"-.e results of tke cr-.pu t aticons i. ete-' a value
oif nrp il-dr 'y r-,neff''cent cf ..',?C55 ",:r the u,-'r.
surf r as3 co. na-'re-d with the ar. 'rent vul :' of I..e
r:eas irer! rofile?- ra3 ,-coe ff: ii m- of I..',0. ar .} 3
uo'er si.:rface. Tt 3;ould be nim.ntcni j that t:-e nrof:le-
drag cneffLcients can.iute fro :.'e observ:.d tr: sitlon
points were based on slirnstre..' "r-n -jic -re.nure andi
tiat the nrrofile-drag "ceff :c '-it '.acz on free- str'eu
namic press s ure. ma be obtaine- b'o- "ul1ti -1 n t e
co-, .u,ted nrofil -.:-1.o coefl, -ficients t:,r ratio o','
slipstream dy-na--ic reassure to free-strea.A, d.-nanic
pressure.


CC : L'.'SICO


The rcsi.lts of th1 f'i t.t inv3cst:-.atin rjf oo'.. -dary-
1.yer transition a..id profile dr'ai;, n the. l.ow- l.' ra ''i.?n of
an exnerl mental f igter-tve air l.ane, the ':[-'7 -.-ve
shown that:

Por t'e snciall-. fini.h-ed ri';ht w'in section, -.hich
was &erodynasnicall7 smooth but had enasurable
residual waviness,


C I', TIDZN TRIAL









NACA ACR No. L5CO8a


1. The drag characteristics realized were in reason-
able accord with expectations for the tyre of section
tested.

2. The noint of transition on the upper surface
moved rearward with decreasing lift coefficient to about
50 percent of the chord and then moved forward again
with a further decrease in lift coefficient. This
forward movement of the point of transition was attri-
buted to the increasing '-ynolds number that accompanies
decreasing lift coefficient in flight. The section lift
coefficient and Reynolds number corresponding to transi-
tion at 50 percent of the chord were 0.18 and 15.7 x lo6,
respectively.

3. The profile-d:'s; coefficient decreased with
decreasing lift coefficient until a minimum of 0.0045
was obtained at a section lift coefficient of about 0.19
and a Reynolds number of about 15.9 x 106. With further
decrease in lift coefficient, the orofile-drag coefficient
be-.i: to increase a-a.in by an amount correspondiing to the
forward movement of transition on the upper surface.

4. To difference in the point of transition on the
upper surface or in the profile-dra. coefficient was
observed when the airplane was flown with nornial engine
operation and with engine throttled.

5. An increase in profile-drag coefficient of 6 to
14 percent, at lift coefficients of 0.50 to 0.58,
respectively, above that obtained in normal flight at
lower Mach numbers and corresDonding lift coefficients
was measured in steady turns at an indicated airspeed
of 500 miles per hour with normal accelerations from 2g
to 4g.

For te? standard right wing section with camouflage
paint and normal construction waviness

6. A minimum profile-drag coefficient of 0.0063 was
obtained at a section lift coefficient of 0.22 and a
Reynolds number of 1l!.7 x 106.

7. No increase in profile-drag coefficient above
that obtained in normal flih-it at lower u,'ch numbers and
corresrponiinr- lift coefficients was measured in steady
turns at an indicated airspeed of 300 miles ncr hour.


SC I' FITD I TIAL


COC;rFIDE TIAL











IA2A AR ITo. L--CO 3a


the s ,e: l -1- I'. punished un--er surfac-. ol the le f
v.?in secti n "n t1' ".'e .C r ._ .'- r 31" sst '.ir-

S -. Te t .re war ~d position C' cr. s -lie ,iJr'el
vli t r or.:1 eii In o e r';-Lt on '.'-as -.otv'e.sn 20 i .- -, n r-
cer c r:- a' t a s ct. .: lift o -ef ient ee. ri *?.i'
and C.1.J ani ac s -;e'-nc'lldn ..rl.ter Lbet:':-en 1:." < 1.'-
and 21.5 v 10ls, res-e actively. '! C t-e .er...ine ttro't led,
t .c ros iton of tr9ansi ti n Wvs L, r nc-tn ci tie cl..-
fairther rear.v.a d fr.: ht i: e a i .g th'n u-tt o tj i -C
,witl normal en ine -o.ere ation ,

9. Th.e atten.Tn tro l eau? .- rrof'n. .rr of re
ur,?r s.-rf~ ce -, h': lfr -v -l -t l' ri.-e-d f -:'- .: n t
sUc -sJ rul b- us? :- laree laleral cor.m.nent -f oiuldsar-
l.a;:er flrov e;::S ted it t,.,e trallln- e -e of t.:is 3 ctic.i.


Lar- le v '"e-:,rlsl A'rcn 'ta eia La ,.l.orator.'-
Natiocnal Ad\vi.rr- Coir u .L t te or .A roraut ics
Langie', FPl.e1lb, Va.


C ON 'FIE" T TAL


CONFID'ZN7IhL










NACA ACR Ho. L5CCLa


REFEE TTCES


1. Anderson, Raymond F.: Determination of the Charac-
teristics of Tapered Win s. NACA Rep. No. 572,
1936.

2. Silverstein, A., and Tatzoff, S.: A Siri-olified
Method for Determining "'ir. Profile Drag in Flight.
Jour. Aero. Sci., vol. 7, no. 7, May 1940,
pp. 295-301.

3. Theodorsen, T., and Garrick, I. E.: General Potential
"i-ory of Arbitrary Wing Sections. NACA Rep.
No. 452, 1955.

4. Squire, H. B., and Young, A. D.: The Calculation of
the Profile Drag of Aerofoils. R. & M. No. 1838,
British A.R.C., 1958.

5. von Kdrman, Th.: Compressibility Effects in Aero-
dynamics. Jour. Aero. Sci., vol. 8, no. 9,
July 31i.1, op. 357-556.


CO I;' ID ETI AL


CONFIDENTIAL









NACA ACR No. L5CO3a


TABLE I

OCFDINATES OF RTI3iT X.'IIG SECTION OF XP-L7F AIRPLA'iE


[All values are given in fractions of chord. Ordinates
were measured relative to an arbitrary chord and
with inboard T.E. of aileron in line 'ith T.E.
of flan.]

Ordinate
Station
Upper i Lower
surface surface

0 0 0
.0125 .0139 -.0165
.025 .026 -.0215
.050 .0o1 -.0275
.075 .0 5 -.055
.10 .ohio -O.057O
.15 .058 -.055
.20 .06 2 -.0501
.25 .0725 -.05.6
.3u .0770 -.0531
.?5 .OJo. -.o605
.40 .Od2o -.0620
.45 .oS0i -.0629
.50 .03~O0 .06
.o .0796 -.o6o
.70 .0671 -.0506
0 .04-b2 -0.3l)
.90 .0196 -.0129
1.000 0 0
!_


IrATICONAL ADIVISCR /
COM!"J!ITTEE FOR AEROiTAUTICS


CON"TrDEr"TAL


CONFIDENTIAL











NACA ACR No. L5CO8a Fig. 1



























lif4








E-











--














zz.
c





-4



r-






NACA ACR No. L5CO8a


NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS


Figure 2.- Setch of XP-47F airplane showing


location of wing


test sections.


CONFIDENTIAL


CONFIDENTIAL


Fig. 2










NACA ACR No. L5CO8a Fig. 3















4c




S0t







-4
tc6














a




Cd 0
Cd




$4
c3











~bo







-
cC cc
-o 2
1-4


o -o










.,-
oo




UU


a.

be0



C4







NACA ACR No. L5CO8a


Upper surface


Lower surface ------
LJ_____________


S /Upper surface


Lower surface- "

(a) Measurements 6 inches outboard of section
center line.


(b) Measurements at section center line.


(c) Measurements 6 inches inboard of section
center line.

Figure 4.- Surface-waviness index of smooth surfaces
cf right wing section. XP-47F airplane.
NATIONAL ADVISORY
CONFIDENT TI AL COMMITTEE FOR AERONAUTICS


4.0xfo-
4. Ox Io,


4.0 X


Fig. 4a,b,c


CONFIDENTIAL


,j\


I I i I I






NACA ACR No. L5CO8a


(a) Measurements 6 inches outboard
center line.
-4


of section


(b) Measurements at section center line.


(c) Measurements 6 inches inboard of section
center line.

Figure 5.- Surface-waviness index of smooth upper
surface of left wing section in slipstream.
XP-47F airplane.
NATIONAL ADVISORY
CONFIDENTIAL COMMITTEE FOR AERONAUTICS


""""I I i I I I I I I I lir


I i TY-Tt-rY-IVTc~l`


Fig. 5a,b,c


CONFIDENTIAL









NACA ACR No. L5C08a Fig. 6















0










c iCd f- Zma>
0 0W








%4 E-
a _r a z



rz. C)3
-- u














00
m a m a .j
Q. -> c- S










I< -- -- O
S 3 La


S--



--- -- -- ^-^ ~-' ---I *M *











o! bo


Ex-







NACA ACR No. L5CO8a


Figure 7.- Rake installation for wake surveys on right
wing section. XP-47F airplane.


Figure 8.- Half-wake trailing-edge rake used for wake
survey on upper surface of left wing section in pro-
peller slipstream. XP-47F airplane.
CONFIDENTIAL


CONFIDENTIAL


Figs. 7,8








NACA ACR No. L5CO8a


Upper surface


X/c
0 ExperimenLal
theoretical
--- Theoretical


5 .8 1.O
NATIONAL ADVISORY
CONNITTEE FOR AEIINUTICS
Ce 0.200, M 0.46
Ct 0.177, M 0
cL 0.200, M 0.46


Figure 9.- Pressure disLribulion over smooth right
wine secLion. XP-47F airplane.


CONFIDENTIAL


Fig. 9


CONFIDENTIAL






NACA ACR No. L5CO8a


0 Power on
+ Power off
A Normal acceleration of 2g


I C.,




8C,
cli



lct
VC,


ThVF~RImf&iTTTV


- -- ----.--

t --- ----
SO-

0

.3


0


3 .


.2
.I
0
.3
.2.
l
oJ


-a-48


;'0.40


H t =0.30


r


I I I II I I r i u


dI I I i "i j
fame A& o $


SIl vr0.20


C NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS
Figure 10.- Transition as determined on smooth upper
surface of right wing section. XP-47F airplane.
CONFIDENTIAL


ki ff j;-- ,..... -- -- -- -- -- 1


- :t:Hl- _


Fig. 10


CONFIDENT AL


J


vA:= ZO


ttttttMi-Wt








NACA ACR No. L5CO8a


20x


'(C .20l

.10


Figure 11.- Point of transition on smooth upper surface
of right wing section as function of section lift
coefficient. Reynolds numbers for corresponding sec-
tion lift coefficients plo .ed above. XP-47F airplane.

CON FIDENTI AL


-~\-






NATIONAL ADVISORY
COMMITTEE FOI AERONAUTICS
I .I


I


jji jj _A---, | --A. .


CONFIDENTIAL


Fig. 11
























M



ZOx


R


CONFIDENTIAL NACA ACP No. L5CO8a
0 Smooth surfaces, power on
+ Smooth surfaces, power off
X Standard surfaces, power on


0
0 -.- -.-.- -.-. ,- ...



5
0
5 ------0----

3 ------


C1 NATIONAL ADVISORY
COMMITTEE FOB AERONAUTICS

Figure 12.- Profile-drag coefficient of right wing
section with smooth and standard surface finishes,
in normal flight. XP-47F airplane.


CONFIDENTIAL


Fig. 12






NACA ACE No. L5CO8a

400-+----
300
VIO 00- ---


0
.o




R I
5
0


CONFIDENTIAL


L I I "' I "P' r ^i~iX
16


07 A.e


S--


.o080


cd.


I I I I I I I I
-- Smooth surfaces, with high wing loading
---Standard surfaces, with high wing loading
---Smooth surfaces, in level flight
---Standard surfaces, in level flight



I I I I I I I l4* -.5


.0070--- 1 2d1-




.0050 --
-- ^_ __ _


" "0o


.2 .3
C(


Figure 13.- Profile-drag coefficient of right wing section
with smooth and standard surface finishes in the high
wing-loading conditions. XP-47F airplane.
CON FENTA NATIONAL ADVISORY
CONFI DEN TIALONAUTICS
COMMITTEE FOR AERONAUTICS


.


Fig. 13






NACA ACR No. L5CO8a


4-44X4


4--H~


o Power on
+ Power off





-

VPPI ITT1


,X/c=0.15


v---
.3
Jb^--
Sc,. -

.3

VCR .I


X/-irO.O5


O .08 .16 .Z4 .32 .40 .48 .6 .44

Figure 14.- Transition as determined on smooth upper
surface of left wing section in slipstream.
XP-47F airplane.
NATIONAL ADVISORY
CONFIDENTIAL COMMITTEE FOR AERONAUTICS


20x


.3
,&, 2.
itt .1
0
.3

9cr .I
0
.3

Scf2


[


II


--


I
mAA


Fig. 14


CONFIDENTIAL







NACA ACR No. L5CO8a


20x 1
2OxIQ [O --,- -,- -,- -- ---




R 10




0






--------csimFB EOATC
Power off
.20 Q ^ -









0 .2 .3 .4 .1

--+-- Power off
Figure 15.- Point of tranwetion on smooth upper
surface of left wing section in slipstream as
function of section lift coefficient. Reynolds
numbers for corresponding section lift coeffi-
cients plotted above. XP-47F airplane.


CONFIDENT AL


Fi g. 15


CONFIDENTIAL























I





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