This note presents the results of flight pressure-distribution tests on the right upper wing panel of a Douglas M-3 airplane equipped with an elliptical tip of length equal to the wing chord. The results are given in such form that the load distribution for any normal-force coefficient within the usual range encountered in flight may easily be determined

Rhode, Richard V

English

NASA Technical Reports Server

II T“i;HiiICAL NOTES
NATIONALA9VISORY COMMITT’EXFOR
——
No. 43?
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{
AERONAUTICS
TEE PRXSSURE DISTRIBUTION0V5R A LOXG I?LLIF!I’ICAL
WING TIP ON A Z!IPLANEIN FLIGET
By Richard V. Rhode
‘LangleyMemorialAeronauticalLaboratory
.=_ _
a-
https://ntrs.nasa.gov/search.jsp?R=19930081227 2020-03-17T04:00:42+00:00Z
.-.
.
AERONAUTICS
—.--—
TECHITICALNOTE NO. 437
—.—
THE PRESSURE DISTRIBUTIONOVER A LONG ELLIPTICAL
WING TIP ON A 31P-LANEIN FLIGHT
By Richar,dV. Rhode
SUMMARY
This note presents the results of flightpressure-dis-
tributiontests on the right upper wing panel of a Douglas
M-3 airplane equippedwith an ellipticaltip of length
equal to the wing chord.
The results are given in such form that the load dis-
tributionfor any normal-forcecoefficientwithin the usual
range encounteredin flight may easily be determined.
b INTRODUCTION
4 This note presents the results o%tained in pressure-
di.stributiont,estsin flight on an ellipticalwing tip
whose lengt-hequals the wing chord. This tip is the eighth
and last of a seriesunder investigation. Results of the
previous seven tips have been reportedas follows: the
“Douglas”tip in reference1; the square tip, both with and
without faired end, in reference2; the semicirculartip in
reference3; a modified ellipticaltip in reference4; a
standardNavy elliptical tip in reference 5; and a modified
Navy ellipticaltip also in reference5.
As in previous tests, a rounded tip of the Douglas
form was used on the right lower panel below the tip under
investigation,which procedure did not, as shown hy pre-
vious tests (reference 2), introduceany effect in the re-
* Sultso
-.
The tests were made at Lqngley Yield, Vs., by the
l ?kktionalAdvisory Committeefor Aeronautics,late in 1931.
—-
—
—
2 N.A.C.A.TechnicalNote No. 437
METHODSAND APFARATUS
The M-3 airplanethat was used in these tests is a
normal biplanehaving,however,an aspect ratio somewhat
higher than usual. The characteristicsof this airplane
are given in Table 1. The shape of the wiag tip is shown
in Figure 1, and the ordinates.of the rib profiles in
Table 11. The ClarkY sectionwas maintainedas closely.
as practicablethroughoutthe span. ,-
The wings were rigged with a slight washin, sufficient
approximatelyto cancel the torsionaldeflectionat the low
angles of attack. At the higher angles of attack, this -
rigged washin was not canceledby the negligibletorsional
deflection,so that a slight twist in the wing was present.
However, this twist has no noticeableeffectat high angles
of attack,and the resultsmay thereforehe consideredto
representconditionsfor no twist throughoutthe angle-of-
attack range investigated.
—
..,-
A portion of the tests was made with the tip covered
with fabric. The tip was later coveredwith plywood to
provide a more nearl,yperfect shape,becausethe true pro-
file couldnot be maintainednear the tip between ribs by
the use of fabric.
In other respectsthe same procedurewas used in these
tests as was used in the previous tests. (References1, 2,
3, 4, and 5.)
. —
—
.—
“=
8
, ..
All measurementswere made in unyawed conditionsof
flight. .,
PRECISION
.
As mentionedin references1 arid2, the-accuracyof
these tests was maintainedat a relativelyhigh level,
largelybecause of the installationof all instrumentsin
an insulatedcompartment,
-1
which was kept at a constantter- n,*,;
perature. The discussionof precisiongiven in reference1
applies to all measurementsgiven, as no changeswere made
in apparatus,methods, or procedure. a-
N.A.C.A.TechnicalNote No. 437- .: 3
RESULTS
The results of the tests made with plywood covering
showed slight differencesfrom the results olt,ainedwith
the falmic covering. These differences,however,were
within the experimentalerror except,possibly,for rib Y
for which a scimewilatgreater differencewas appar”entnear
zero lift. It is not believed that the slight differences
observedar6 in any case good evidenceof true variations
in the resultsas caused by the type of covering. For this
reason,the results for both types of coveringhave %een
ave”rag~a”-ridare thus presented in Figures 2 and 3, and in
Tables 111 and IV.
The coefficientsreferredto in the resultsare defined
a’sfollows:
wing %7= w3i_nQxmQg~q X wing area
Rib rib normal force~per unit spqnJ——--% = —--~ x rib chord
RilI Cm = moment of rib normal force about L,E.—-——— —-.—.
qx ~rib chor~---———
The curves of Figures 2 and 3 were establishedby a
large number of points as in Figures 6 and 7 of reference1,
but the points have been omitted to avoid confusion. Curves
for the root sectionwere obtainedby extrapolatingspan
c~ and span Cm curves from considerabledata. Owing to
the extrapolation,the curves do not representthe true
conditionsnear the fuselageand in the slipstream,but
representmore nearly the ideal conditionsin which there
is no effect from fuselageand propeller.
Laggley MemorialAeronauticalLaboratory,
NationalAdvisory Committeg$-orAe.ronauti.cs,
Langley Field,
-.4.-..
Vs., November18, 1932.
4 N.A,C.A. TechnicallToteNo. 437
RE3’3RENCES 4
1. Rhode, RichardV., and LundquistS Eugene E.: T%e
PressureDistributionover a Douglas Wing Tip on
a Biplane in Flight. T.N, NO. 347, N.A.C.A,, 1930.
2. Rhode, RichardY., and LundquistjEugene E.: The
PressureDistributionover a Square Wing Tip on a
Biplane in I?I.ight.T.N. ~0. 350, N,A.C.A,, 1931.
3. Rhode, Richard1’., and Lundquist,Eugene E.: Tne
PressureDistributionover a,SemicircularWing Tip
on a Biplane in ‘Flight. T.N. NO, 379, N.A.C.A.,
1931.
4. Rhode, RichardV., and Lundquist,Eugene E.: The
PressureDistributionover a ModifiedElliptical
Wing Tip on a Biplane in Flight. T.N, NO. 387,
Ii.,A.C.A,, 1931.
5. Rhode, RichardV.: The PressureDistri~utionover a
Standardand a ModifiedNavy EllipticalWing Tip
on a Biplane in Flight. T.H, NO, 433, N,A.C.A.,
1932.
‘.
—
.—
—
.
—
.=
.
—
-.
.
4
.“
-.
r
N.A.C,A. ‘TechnicalNote No. 437’
.+
.. ...
TABLE I
CHARACTERISTICSOr i)OUGSIASM-3 AIRFL.4NE
Type... . . . . . . . . . . . . . . . Biplane
Airfoil. . . . . . ,. . . . . . . . . . Clark Y
Span (upper and lower) . . . . . . 45.ft. 10 ill.
Chord (upperand lower) . . . . . . 5 ft. 8 in.
Gap. . . . . . . . . . . . . . . . 6 ft. O tn.
Stagger. . . . . . . . . . . . . .
e.g. in per cent of chord . . . . . .
Areas (sq.ft.) Original
Right upper wing, including
aileron. . . . . . . . . . . .
&
Right lower wing, including
aileron. . . . . . . . . . .
4
Total wing area . . . . . . . . .
Horizontaltail surfaces . . . . ,
Vertical tail surfaces . . . . . .
Weight during tests . . . . . . . .
Engine. . . . . . . . . . , . . . .
Rated hp at 1,’750r.p.m. . . . . . .
126.4
126.4
505.6
58
17.7 .
4,840 lb.
Liberty
420 ...
None
29
Long
elliptical*
123
126.4 -
502.2
Power loading . . . , .,. . . . . . .,,’11.52 lb./hp
ITi~gloadiag.. .. . . . . . . . . 9.57 l-b./sq.ft.
*Left wiug panels remained.unchanged.
—-
.. .. . . .. . . .— -- .— ...-— .. ..—
Station
$ ~ard
.00
1.25
2.50
5.00
?.50
10.00
15.oo
20.00
30.00
40.00
50.00
60.00
7a.00
&l.oo
90.03
95.(X)
,03.00
!U3LEH
COMPARISONOF SPECIFIEDMD MEAWREDORDINATESOFPRESSERERIBS
(LongEllipticalTi?)
[g~er
3.50
5.45
6.50
7.90
8.85
9.60
.0.68
.1.36
.1.70
.1.40
.0.51!
9.14
7+35
5’.21I
2..8(2
1,.48
.12
~~
!
I
3.50 3.40 3.40
1-.93I5.47, 1.84
~
1.46 6.52 1.29
3
.93 7,90 >&?
.62. 8.82 .51
.42 ‘9.65
b
.41
.15 C4.fl da
.03331,.21 .05
.00 1.67 .00
F
.00 1.30 .00
.00 0.48
I
‘-w
.00, 9.X2 .00
i
-m 7i.3i5 .09
J_
.00 5,.3a .00
.0012 .90 .@
I.Cx31.65koo.00i .37 .00
1, il
RibA
,
r~per;Lo~er
~
3.49 3.48
5.56 1.93
6.52 1.47
g.Qc ,CJy
9.05 .66
9.74 .46
.0.76 .2a
,1.26 .09
.l.’n .00
,1.36 .00
.0.48 .00
9.19 -.05
7,36’. .00
5.33 ,00
2.@Q,-.05
J_
1.52 -.09
.23 -.23
&
T,-3.36 3.36 3.94 3.44“5.34 1.79 5.47 1.s56.38 1.33 6.43 1.427.90 .63 7.@J .928.91 .28 8.74 .649.65 .32 9.54 .44
.0.63 .14I1O.6O .15
:1.26 .05‘11.29 .02
.1.81 .00 11.58 .00
!1.40’ .05 11.23 A2
0.58’ .(K510.35 .05
9.42 .09 9.07 .05
7.6%, .09 7.31 .06
., .
J___Fi_‘: 4 ‘: ‘~
.
Note:Allordinates<ivenareinpercent.of chord.
RibD I RibE RibF
3.58 i3.58 3.65
5.67 1.87 5.30
6.49 1.41, 6.28
7.78 ,98 7.72
8.77 .65 8.70
9.51 .43 9.46
.0,50 .17 10.48
.L171..0011.16
.1*53 .CQ11.73
.L27 .00lZ.28
.0.45
i
.0510.37
9.06 .05 9.01
7.26 .05 7.06
5.19 .09 4.92
2.79 .12 2.50
1.54/ .12 1.23
.26
I
.07,, ,15
,: ,,
~
--++
3.55 3.52 i
2.m 5.69 I
1.51 6.48
.95 7.78
.53 8.76’
.32 9.4e
.15 10.62
.06 11.24
.00 11.58
.0011 .27
[
.(x)10.34
.02 9.(X3
.00f 7.28
.oo~ 5.17
~“
.00 2.55
.m 1.38
-.!34~ .L4,
3.52
1.s3
~=~~
1.00
.69
.48
.21
.10
.00
.00
.00
.00
.09
.03
.00
.03
,.00
II I,, ,,, . I 1:, 1.
.-
ol
I
N.A.C.A. TechnicalNote No. 437
.—-— —
Wing
CN
.—— —
0
.1
.2
.3
.4
05
.6
.7
.8
.9
1.0
1.1
1.2
1.3
la4.
1.5
1.6
TABLE 111
,
COORDINATES01’CURVES 01’FIGURE 2
————-—- —— —.
—— --——
Xoot7 x
)“.0000.000
.120 .115
.239 .228
.358 *340
.476 .452
.595 .566
.713 .679
.833 .794
.951 .908
1.070 1.020
1.187 1.134
1.306 1.247
1.421 1.360
L.532 1.472
S.640 1.583
1.740 1.690
1.836 1.795
Rib CN
—-—.
A
.—-.
).000
.100
.200
.300
.400
.500
l 600
.’700
.800
.900
L.000
L.1OO
1..2OO
1..3OO
1..4OO
L.500
L:600
——
B
).000
.083
.166
.248
.330
.412
.495
.578
.661
,744
.827’
,910
l994
1.076
1.158’
I
1.240
1.321’
—-.
c
0.000
.083
.168
.251
.335
.420
.503
.588
.672
.756
.842
.926
1.010
1.094
1.178
1.261
1.345
—-
D
:
CEO
.081
.162
.243
.325
.405
.487
.569
.651
.731
.813
.896
.980
L.065
L:155
L.Z50
L.351
E
-—
).000
.076
.154
.233
.315
.396
.478
.56Q
.645
.729
.815
.902
.995
).092
1..195
L.305
1..425
).000
.050
.1o4
.165
.230
.308
.392
.484
.581
,684
.796
.911
1.035.
1.164
1.300
L.440
1.582
8. —-
Rib
c~.-—-
0
.1
.2
l3
.4
.5
.6
.7
.8
.9
1.0
1.1
L.2
L.3
L.4
L.5
L,.6
L.7
1,.8
N.A.C.A.Techn3.calNote No. 437
TABLE IV l
COORDINATESOF CURYES OF FIGURE 3
-L
-———-— —— ..————--— —— ———. .--——-—-——--——.. —
.
--———.
Root
-—— —
“0.071
-,094
-.118
-.142
-.165
-.188
-.212
-.236
-.259
-.283
-.306
-.329
-.353
-,376
-.400
-.424
-,447
-.471
- *494
——--_—
x—..—---
-0.068
-.09Q
-.113
-.137
-.160
-.184
-.208
-.232
-.256
-.279
--.302
-.326
-.349
-.372
-.395
~.418
-.441
-.463
-.485
Rib Cm
———-—-
A
..-———
-().074
-“.096
-s.118.-
-*141
-.164
v.187
-.209
-.232
-.254
-.277
-.299
-.321
- ,343
-}363
-,384
-,404
--.423
-———
B
-———..-
-0.073
-.092
-.112
-.132
-,153
-.174
-.196
-.217
-.238
-.260
-.281
-.302
-.323
- l 344
-—-——-
C...-——
-0;068
-,_089
-.110
-.131
-.154
-.176
-.199
-*222
-.246
-.270
-.293
-.315
-.337
-.357!
-,
--
.
-
——-—.
D
-—. -
-0.(368
-.087
-.166
-.125
-.147
-,171
-.164
-.219
- .2i4
-.2;8
-.293
-.318
-.344
-,389
-.394
-- -—-
E
-——- -
-0.057
-.077
-.098
-.120
-.144
-,169
-.195
-.222
-.250
-.279
-.308
-.337
-.367
-.398
~.428
-——
*7
..—— --
-O*O4E
-.06E
-.091
-.324
-.444
-.526
A. 568
-.610
—
?
.
* l
h 1 chord >
4.081 >k-----ml >1.001~5.~l_J+Q7117.371
22.871 -1
f)
\.
Fig.1 M-3wingwithpressmerib6andorificelocations.(Lo%
P
N.A.C.A.TechnicalNoteNo.437 Fig.2
Root
1.8-
..—.-
1.6 - l-
l.k
1.2
~a
/
~ 1.0I%
.8-
.6- .—.
.
~
.2— --
0 .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8
wing c~
Fig.2 Rib~w againstWingCII
.
o .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2%0
i
-.1
I
2-. -%
JI
@ -.3 \
2
\
\
-.4 - x\
-.5
.....--- . .---
,,“3’‘-
-.6- 1 x
I
I
,


The pressure distribution over a long elliptical wing tip on a biplane in flight

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