Weight estimate of cantilever monoplane wings of corrugated aluminum alloy box-type construction for pursuit, attack, twin-engined observation and transport airplanes (Airplane Branch report)

              μ
(N P:J~ fl/-z- ?. 1 / "~ ING
File D 00.12/ 122 / No. 3496 W R CORPS TECHNICAL REPORT No. 3496
AIR CORPS INFORMATION CIRCULAR
PUBLISHED BY THE CHIEF OF THE AIR CORPS, WASHINGTON, D. C.
Vol. VII October 30, 1931 No. 662
WEIGHT ESTIMATE OF CANTILEVER MONOPLANE WINGS
OF CORRUGATED ALUMINUM ALLOY BOX-TYPE CONSTRUCTION
FOR PURSUIT, ATTACK, TWIN-ENGINED OBSERVATION
AND TRANSPORT AIRPLANES
(AIRPLANE BRANCH REPORT)
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1931
Ralph Brown Draughon
LIBRARY
JUN 18 Z013
Non·Depoitory
Auburn University
J
/
WEIGHT ESTIMATE OF CANTILEVER MONOPLANE WINGS
OF CORRUGATED ALUMINUM ALLOY BOX- PE CON­STRUCTION
FOR PURSUIT, ATTACK, T IN-ENGINED
OBSERVATION, AND TRANSPORT AIRPLANES
(Prepared by Charles G. Brown, Materiel Division, Air Corps, Wright Field, Dayton, Ohio, June 12, 1931)
OBJECT
The object of this study was to determine, as closely
as a rough design would permit, the unit weight at
which metal wings of box construction could be built
for pursuit, attack, twin-engined observation, and
transport airplanes.
DESIGN FEATURES AND CONDITIONS
The principal features of construction to be used in
the design of these wings are:
(a) That a corrugated flange shall extend across the
upper chord between two thin metal webs. This flange
shall carry the compression due to high and low inci­dence
loadings. The pitch of the corrugations shall be
2% inches and the depth three-fourths inch.
(b) Heavy flange angles shall be used for joining the
webs and upper corrugated flange.
(c) The webs shall be unlightened fl.at sheets of
aluminum alloy stiffened with vertical angle members,
to be used in pairs, one on either side cf the web. These
stiffeners shall act also as a means of attaching the
bulkheads to the webs of the box portion of the wing.
Although the weight estimate will be made on the basis
of unlightened webs, it is felt that lightened webs, of
the double Pratt truss type, having plain fl.at tension
members, can be used advantageously, with a probable
saving in weight where sections are deep. Any loss in
rigidity due to using this type of web will be small.
(d) The upper covering, from front web to trailing
edge, shall be of corrugated aluminum alloy sheet of
IX-inch pitch and %-inch depth. This material will
support the corrugated material of the box section to
such an extent that a coefficient of fixity of -three may
be used in the design of the flanges. It '\\ill also reduce
the material that must be put into ribs or bulkheads
to the rear of the rear spar.
(e) The lower skin shall be of fl.at sheet stock and
will be considered as a part of the tension flange of the
box section of the wing in the high and low incidence
conditions. The tension in this lower flange may be
considered as tapering from the tension at the webs to
zero at the leading and trailing edges; hence any
splices outside of the box portion must be designed to
carry tension loads. The fl.at skin will extend from
the front webs on the upper chord, around the wing to
the trailing edge.
chord loads. This flange will be well supported by
the lower skin.
(g) The compression loads in the lower flange in the
inverted flight condition shall be resisted entirely by
the flange angles at the webs, no corrugated material
being provided on the lower chord. The fl.at skin
shall be considered as having no resistance to compres­sive
loads.
(h) For the purposes of this study it will be con­sidered
sufficiently accurate to assume a uniform dis­tribution
of stress across the corrugated flange.
(i) The position of the airfoil vector in the nose-di rn
condition will be that for the Gottingen 398 airfoil, as
shown in Serial No. 3293, Air Forces and Moments
Acting on Airplanes, for the pursuit and attack wings.
The torque at the wing root will be that due to this
extreme position of the airfoil vector.
(j) Studies of the strength of corrugated aluminum
alloy sheets in shear being conducted at this date indi­cate
that the flange material provided in the upper
flange will be sufficient to resist the shears due to nose­dive
torque.
(k) The wings shall taper both in planform and
thickness ratio, and shall be similar in planform.
(Z) A modified USA 35 airfoil having a root thickness
ratio of 18.46 per cent and a tip thickness ratio of
11.76 per cent will be used. The center of pressure
location for high incidence and inverted flight will be
taken at 31 per cent chord; for low incidence at 52 per
cent chord. The chord to beam ratio for high incidence
shall be taken as -Q.158; for low incidence +0.150;
and for inverted flight, zero.
(m) In computing the shears and moments, an esti­mated
dead weight of 1.75 pounds per square foot shall
be used. This will be assumed to be distributed uni­formly
over the equivalent wing area.
(n) The computed weight of the wings will be in ­creased
10 per cent to allow for all items not actually
included in the weight estimate.
Note
Studies completed after this report had been com­pleted
indicate that the method of analysis used is
applicable only to a rough design or approximation.
The stresses developed in a wing structure of the type
considered have been found to vary in accordance with
the flexure formula.
(J) Ribs of a double Pratt truss type having fl.at
tension members will be considered. The lower flange
of the ribs will be made sufficiently heavy to resist the
compression between front and rear webs due to
The moment of inertia I should be determined by
considering only the box portion unless the other por­(
1)
tions of the wing are sufficiently reinforced to carry
high stresses.
For a later and more complete discussion of stresses
in wings of the type herein considered see--
Serial 3227, A. D. M. 1110.-Column Properties of Cor­rugated
Aluminum Alloy Sheet.
Serial 3415, A. D. M. 1168.-Static Test of Materiel
Division 27-foot Metal Cantilever Wing and Driggs
Dart 27-foot Wood Cantilever Wing.
Serial 3501, A. D. M. 1169.-Static Test and Stre s
Distribution Studies of the Materiel Division 55-foot
Metal Wing.
Serial--, A. D. M. 1203.-Shear Strength of Cor­rugated
Aluminum Alloy Sheet.
Serial--, A. D. M. 1207.-Structural Design of the
Materiel Division YlC-12 Metal Wing.
Summary of estimated wing weights
Wing
t:lpan _________ __________ reet :
Hoot chord ___ _______ inches ..
Wing area ....... square feet..
Oross weight of airplane
-- - - - __________ ___ pounds ..
Load factor, Il. L ___ _________
Load factor, L. !_ ______ ______
Loarl factor, I. F ___ ____ ____ __
Es,,t·iimnga _te__d_ __d_e_a_d_ __w_ _e_i_g_h_t_ __o_f_
Computed weight _______ _____
1.10 X computed weight_ _____
Twiu­Pursuit
Attack e~i;~;_d
vat ion
32 46l-3 64
72 108 144
IGO 3(}! 578
2,200 5,000 8,000
12 8.5 8.5
6. 5 5. 5 5. 5
4 3. 5 3.5
1. 75 1. 75 1. 75
1. 71 l. 79 J.42
1.88 1. 97 1. 56
'frans­port
79
170
854
12, 500
5. 5
3.5
2.5
1. 75
1.42
1. 56
Corrugated upper cover
Websliffeninj an_sles
Unli3htened web Fla.Hower cover
Fm URE 1.-Typical wing cross section
Angle sections
R.
FIGURE 2
Area= [a±b+c+ ... R] t
tSi eon~ 1 a I b I c I R t Area Where used
Xo.
-- __ ,_ -- -- -
2l 1% %•---- Vi o. 094 0. 231 Pursuit upper fiange. 1% %•---- l4 .125 .310 Do.
3
1% I %•---- l4 .064 1 .157
4 ll4 l4 1---- l4 .004 . 214 Pursuit lower fiange.
5 J!,{i !Ao---· J4 . 094 .184 Do .
6 lJ.{i !A•'---- ~~ . 050 .098 Do .
7 J>i l4 1---- l4 . 050 .114 Do .
8 1% I ~ ---- l4 .125 . 380 A \tack lower flange.
9 H~ l4 ---- l4 . 125 . 316 Do .
10 l;{i ~ l4 .064 . 190 .Do.
lt J>{i !Ao:::: J4 .050 .09 Do.
12 1!4 l4 .)4 .064 . 146 Do .
13 l ~ "r:::, ~. .156 .470
14 1% % ---- l4 .125 . 345
15 2~1·1 % l4 ~1. .156 .630
16 2J.{i ~:1··~ l4 .093 . 313
17 2J.{i l4 . 093 .325
1 2J.{i Jli•1 Yo ~i .125 .43~
19 2~· 1 % ~ , ~4 .156 .680
2
DESIGN OF METAL WINGS
Types of wings
I. PURSUIT (SK-15978)
Span ______________________ 32 feet.
Root chord ________________ 72 inches.
Wing area _________________ 160 square feet.
Gross weight, airplane ______ 2,200 pounds.
Factors, H. !_ _____________ 12.
Factors, L. !_ ______________ 6.5.
Factors, I. F _______________ 4.0.
Estimated weight, 1.56-1.75 pounds per square foot.
II. ATTACK (XA-7)
Span __________ _________ ___ 46 feet, 4 inches.
Root chord ________________ 108 inches.
Wing area _________________ 304 square feet.
Gross weight, airplane ______ 5,000 pound.
Factors, H. !_ _____________ 8.5.
Factors, L. !_ ____________ __ 5.5.
Factors, I. F ____________ ___ 3.5.
Estimated weight, 1.93-2.2 pounds per square foot.
III. TWIN-ENGINED OBSERVATION-FAS'!' DAY BOMBER
Span ______________________ 64 feet.
Root chord________________ 12 feet.
Wing area_________________ 578 square feet.
Gross weight, airplane ______ 8,000 pounds.
Factors, H. !_ _____________ 8.5.
Factors, L. !_ ______________ 5.5.
Factors, I. F _____ _______ ___ 3.5.
Estimated weight, 1.75 pounds per square foot.
X0-27-TWIN-ENGINED 0BSERVA'l'ION
Gross weight _______________ 7,950 pounds (say 8,000
pounds).
Wing loading ______________ 13.75 pounds per square
foot.
Total area _________________ 578 square feet.
Effective area ______________ 471 square feet.
Useful area ________________ 558.4 square feet.
Root chord ________________ 144 inches.
Tip chord ________________ _
Span ______________________ 64 feet.
Factors ___________________ 8.5; 5.5; 3.
FORD 4-AT
Gross weight _______________ 9,300 pounds.
Total wing area____________ 7 49 square feet.
Root chord ________________ 154 inches.
Tip chord _________________ 92 inches.
Span ______________________ 68 feet.
Effective area ______________ 648 square feet.
FOKKER F-XA
Gross weight _______________ 12,500 pounds.
Wing area __ _______________ 854 square feet.
Wing loading ______________ 14.7 pounds per square
foot.
Useful area ___ _____________ 785 square feet.
Span ______________________ 791 feet.
Factors____________________ 4.5; 3; 1.8.
Root chord ________________ 170 inches.
I. PURSUIT WING
Thickness ratio chord, CD=1
3
5°2
x(18.46 - 11.76) +
11.76=13.08 per cent chord.
Gross weight of airplane, 2,200 pounds.
Total wing arna, 160 square feet.
Estimated wing weight, 160Xl.75=2 C pounds.
Thickness ratio chord, AB=ll.76- Computation of loading OYer equivalent wing- 1
2
: 2 (18.46-
11.76) = 10.16 per cent chord. 6882W +0.915X1525W=l,100 pounds-140.
8278W=0.961 pound.
Equivalent chord, CD'=i~:~~ X 55 =39 inches. W =0.116 pound per square
inch.
Equivalent chord, AB'=i~:~~X30 = 16.5 inches.
The factor 0.915 represents the mean loading over
the tip portion of the wing. This is a computed value
and is slightly greater than the 0.90 prescribed for use
with a loading which tapers to 0.8 at the extreme t ip.
(165+39) X55 .
Area, AB'CD'=---2 --= l,525 squaremches.
Area, CD'EF = (39 ~ 72 ) x l22 =6,882squareinches.
lZ.75
TotaL ____ _______ ____ __ 8,407 square inches.
gi--~~~~~~~~~-177
.m_Front web
7~ ~9 I
· Rea.r web
c ---
D
-----55 ----o-1
r: - - - - - - - ..!:E _ - - - - - - -
7.17. -------- Z9 ------
Root
7Z
FIGURE 3.-Pursuit wing.
PURSUIT WING
Load distribution f actors
Station ____ ...• .. ·----------------------------------- I 2 3 I 4 5 I 6 I· 7
1-------------------1----1--- ---1---------,---
Distance from tip._ -- --- --- ---- ----------- - ----------- - -
Actual chord __ ________ - -------- --- - --- -------- -- _____ -- _
Distance LE-CP 31 per cen t_ __ ________________________ _
Distance LE-CP 52 per cent _ ___ ____ _________________ _
Distance LE-FS __ ____________ _____ __ _________________ _
DDiissttaannccee 3L1E p-eRr Sc e__n_t_-_R__S - _-_-_-_-_-_--__-_--_-__-_--_-_-_-_-_-___-_-_-_-_-_-_-_-_-_-_- -_
Distance 52 per cent-FS _____ ___________________________ _
FS distance factor, H. I. and I. F--- -------------------­RS
distance factor, L. E------------ ----- --------------­FS
distance factorXLF, H. I--- ---- -- ------------- ----­RS
distance factorXLF, L. I ----------- ----------------
~
51.4
15. 90
26. 70
6.16
35.16
19. 26
20. 54
o. 664
o. 709
7, 96
4. 60
1
55 80 105 130 150 177
55 58. 6 62 65. 5 68. 3 72
17. 0 18. 20 19. 20 20. 30 21. 20 22. 30
aro •so n20 KOO ~50 ~w
7. 58 8. 89 10. 21 11. 52 12. 58 14. 00
~58 ~- •n filU il58 AOO
19. 50 19. 69 20. 0 l 2(). 22 20. 38 20. 70
21. 12 21. 61 21. 99 22: 48 22. 92 23. 40
Qm Qm Q~ QB QD Qlli
Qm Qm Q~ Qm Qm QW
s~ su s~ s~ s« sM
4.n 4.U 4.W ~00 ~u ~H
Pistance from leading edge to front spar=6+0.0526 (D-25)
(3)
-
PURSUIT WING
Shears and moments
Station _______ O 1_ ___1 _ \ ___2_ ! ___3_ __1 _4_ __, _s_ __6_ 1 _
1
__1 _
Distance from tip_ __ O
1
______ 28 ----- -- 55 1------- 80 1------- [ 105 ------- 130 - ----- - 150 1------- 177
Chord, equivalent
72 :~~~~~~~~~:~~~: -~~~:_,---~-!----~- 27 -----~~-,----~~- ----~:~~-!,----~~- ----~~~~- 25 ------~~- 20 ----~~~~-,----~~-
pounds per inch __ __ .956 _____ 2.95 ------ - 4.52 ----- -- 5. 3 ------- 6.09 ------- 6.85 ' ------- 7.81 _____ __ 8.35
~et~i~~~~-~=~~~~~- ______ 2.04 3.85 ________ 4.91 ________ _I 5.70 -- --- ---- 6.46 ----- ---- 7.33 I---- ----- 8.08
L~fgns~~~v-~~~-~:~~- __ ____ 56 104 ____ __ _ 123 _____ ____ 142.5 - -------- 61.6 J _________ 146.6 --------- 218
Total unit shear_____ O 56 -- --- - - 160 283 __ _____ 422. 5 __ _____ 597.1 ---- -- - 743. 7 961. 7
Moment SX--------1 0 0 1------- 1, 511 ------- 4,000 -------1 7,080 ------ -1 10, 560 ------- ll, 930 ----- -- 20, 100
Moment w~ - -- -- - ---- -- 784 --- ---- 1, 405 -------- 1, 538 ------- --1 1, 780 I_·------- 2, 020 -------- - 1, 466 - ------ -- 2, 940 _________ _
Totalunitmoment__ O 784 1------- 3,700 9,238 18,098 30, 678 44,074 67,114
H. I. moment__ __ ___ o 9,400 ______ 44,400 llO, 900 216, 000 368,000 530, 000 ------- 804, 000
I. F. moment_____ __ O 3, 140 _______ 14,800
FS distance factor ___ ------ _____ _
FS shear_ __ ______ ______________ _
RS distance factor ___ - ----- - - - -- -
RS shear __ ______ ___________ ------
7. oo 1·---- ---1 8. 08
445 ------- 1, 293
4. 60 ------- 4. 73
257 -- - ·--- 758
36, 950 72,450
8. 15 8. 28
2,308 3,495
4. 5 4. 93
1, 373 2,082
PURSUIT WING
Design of front weir-High incidence
126, 900 176, 800 ------- 269,000
8.38 8. 44 .-- -- - - 8. 56
5,000 6, 260 8,240
5. 05 5.13 5. 24
3, 015 3,815 5,040
A thin unlightened web will be considered. It will be designed to withstand a tensile stress of 55,000
pounds per square foot. The maximum tension is taken as twice tho vertical shear stress at each station.
8tation _______ ____ --------- ---
SDhiestaarn, cIeL fLro m__ _t_i_p___-_-_-_-_-_--_-_-_-_-_-_-_- -_-__- _--
Depth between flange centroids_ _ __
t, required ___ -------- ___ __ __ --- - - --
Actual'------------------------------
28
4<15
3. 52
. 0046
• 020
2 j 3 J 4 5 6 1 1 1 ---1--- 1- 5;; 80 105 130 150 177
1, ~3 2, 308 3~ 495 5, 000 6, 260 8. 240
4. 18 5. 94 {. 10 ~- 26 9. 20 10. 5
• 0098 • 0142 . 01so . 0220 . 0247 _ 0285 I
. 020 . 020 I . 020 . 032 . 032 . 032
Flange depth=3.38+(0.046)(D-25) .
2S
t=55,000d 0
S=sbear stress.
d=deptb.
PURSUIT WING
Design of rear weir-low incidence
___s t a_tio_n_--_-_--_-_--_-_- --_---_-_--_-_-- -_-_--_-_-, ,_ ___1 _ _2_ _ ·--3-- __4_ ___5_ _ --6-- __1_ _
Distance from tip ____ _______________ _
Shear, L. L--------------------------
Distance between flange centroids __ _
t, required __ -------------------------
Actual t_ ____ ---- --- ------------------
28
257
1. 14
.0106
. 016
55 80 105 130 150 177
758 1, 373 2, 082 3, 015 3, 815 5, 040
~- L56 472 ~~ ~U 8.U
. Oll5 . 0141 . 0161 . 0186 . 0203 . 0226
. 016 . 016 . 024 . 024 . 024 . 024
depth=l+0.0465 C0-25).
t . d 2 s . , reqmre = 55,000 d
S=shear stress in. l bs. per sq. in.
d=dc?th. '
Station _____ ----- - ___ - ---- ______
5
PURSUIT WING
Design of web stiffeners
FRONT WEB
2 3 4 6 7
---------------- - -
Shear, F ____________________ pounds _ 445 1, 293 2,308 3, 495 5,000 6, 260 8, 240
Depth between centroids, d_inchcs _ 3. 52 4. 78 5. 94 7. 10 8. 26 9. 20 JO. 5
Spacing, L_ ____ __ _______ _______ do ___ 4 4 4 3. 75 3. 75 3. 75 3. 50
Load, p ____________________ pounds __ I 505 1, 080 1, 555 1, 845 2, 270 2,550 2, 745
Area required ________ square inches __ . 028 .054 .078 . 093 . 113 .128 . 137
Gage of stiffener'-------------------- . 020 . 020 .020 .020 .024 .024 . 032
Stiffener area __________ -------------- .120 . 120 .120 . 120 . 144 .144 .192
REAR WEB
Shear, F ______________ ___ ___ pounds __ 257 758 I, 373 2, 082 3, 015 3, 815 5, 040
Depth between centroids, d __ inches _ 1.14 2. 40 3. 56 4. 72 5. 88 6. 81 8. 12
Spacing, L ____________________ do ____ 4 4 4 3. 75 3. 75 3. 75 3. 50
Load, p ____________ ____ ____ pounds __ 900 1, 265 I, 543 1, 653 1, 983 2, JOO 2, 170
Area required ________ square inches _ . 045 . 063 . 077 . 083 .094 .105 . 106
Gage of stillener '-------------------- .020 .020 . 020 .020 . 020 .020 . 020
Stiffener area ___ --------- ------------ .120 .120 .120 .120 .120 . 120 .120
1 H x % plain angles.
Allowable P/A taken at 20,000 pounds per square inch.
FL
Load P=([ F=shear.
L=stiffener spacing.
d = deptb between centroids of flange angles.
Centroid lower flan ·
15
FIGURE 5
FIGURE 4 Distance between centroids at root= 12 .12 inches.
A conservative distribution of the inverted flight Distance between centroids at tip= l 2 .l 2-7 .1 2~ 5
rnoment is to consider it divided between the front inches.
and rear webs in the same proportion as the high Depth at any station = 5+ 7.12X(~;s_2 = 5+. 0465
incidence shears.
Then, t o determine t he axial load in t he flange (D- 25) .
angles, consider a couple acting at the centroids of the
r ivet groups.
PURSUIT WING
Design of upper flange, H. I .
Station_ _____ -------- ________ ___ _________ 2
Moment, H . L ________________ inch-pound __ 9, 400 44,400 110, 900
Depth between centroids ___________ inches __ 5.14 6. 40 7. 56 Anal load __ ____ __________ __________ pounds _ 1, 830 6, 940 14,630 R ih spacing ________________________ inches __ 16 16 16
11fo~:~r!n~7.A:c.J~;;;::::::::::::::::::::::::: 56 60
29. 400 ------- --- 20, 000
Total area required __________________________ . 732 Net area. covering ___ ____ ___ ________________ . 420
Gage required ____ ___ -------- ____ ---- ________ ---------- ---------- . 011
R/t-------------- ---------------------------- 42
Allowable P/A bu ckling _____________________ ---------- -- ------ -- 23, 000
Actual gage, estimated _____________________ .016
F lange angle section ____________________ No _ 3 3 3
Area __________ ---- --- _________ square inch __ . 314 .314 . 314
4 5
216, 000 368, 000
8. 72 9. 89
24, 660 37, 250
15 15
56 56
25, 000 29. 000
I. 986 I. 285
. 523 . 822
. 0146 . 023
34 27
25, 000 29, 000
. 020 . 025
1 1
. 462 . 462
2)1-iuch pitch, %-inch depth corrugations-R=.95 D=.675 inch. Design stresses from A. D. M . 1110, C=3.
6 7
530. 000 804, 000
10.82 12. 12
48, 900 66, 300
15 14
56 52
33, 000 36, 000
1. 480 I. 842
1.017 1. 379
. 02ll5 . 0386
21 13. 5
33, 000 36, 000
. 032 . 040
1 l
. 462 . 462
p= .359 D= .269 inch. Allowable stresses in flange angles taken same as those in corrugated
flanges. Upper flan!{e an!lle area= .463 squ are inch.
. 7.12 )
P epth hetweel) centro1ds=5+ 152 (D-25
6
PURSUIT WING
Design of lower flange, I. F.
Station ________ -- -- _____ - - - __ ---- - - -- -- - -- 2 3 5 6 7
1------
Total moment__________ _______ ___ ______ ____ __ 3, 140
FS distance factor_ __ ---- --- - - --- -- -- - ------- · _ . 664
14,800 36, 950 72, 450 126, 900 176, 800 269, 000
. 673 . 679 .fOO .698 - 703 . 714
FS moment______ _____ ____ ___ __ ___ __ __ ________ 2, 08.5
HS momrnt_ __ ___ ___ . - - -- -- - ----- -- - -- - - -- ---- l, 055
Distance between centroids, FS__ _____________ 3. 52
9,960 2o, 200 49, 950 I 88,600 124, ()()() 192, 000
4,840 11, 750 22. 500 38,300 52,800 77, 000
4. 78 5.94 7. 10 8. 26 9.20 10.bO
Distaqce between centroids, HS--- - --- - - - --- - - J.14
Axial load, FS______________ ___________ __ _____ .593
Axial load, RS______ ___ ___ __ __ ____ ____________ 920
Area required, FS ______ __ ___ - - - - - -- --- - -- ---- - . 023
Area required, RS_________ ___________ __ _______ . 037
Actual section, FS '------------ - -- -- ---------- 1 ~7
2.40 3. 56 4. 72 5.88 6.81 8.12
2. 080 I 5, 100 7, 040 10. 600 13, 480 18, 300
2,a ~- 'm ~B ~™ 9,490
Allowable P/A taken as 25,000 pounds per square inch
.083 . 204 .281 I .424 . 540 - 732
.081 . 132 .188 .250 . 310 . 318
1 #7 l~ l~ 2~ 2~ 2~
l~ l~ 1 ;5 1 #5 2 #5
Arca, square inch___________ _______________ ___ .114 .114 .328 .328 .612 . 612 . 793
Actual section, RS 1___________________________ 1 #7 l~ 11:4 ]~ { 1~ l~ 1 ~7 l~ } 2~
Area, square inch____ __ ____________________ ___ . 114 .114 . 214 . 214 . 328 . 328 .428
1 See table under Figure 2, p . 2.
Investigation of effect of chord loads on total stresses. PURSUIT WING
Chord loads:
C/B, H . L =-.158.
C/B, L. L= + .15.
Determination of moment of inertia of box section about
vertical axis
Total chord load, H. L =-.158X960 = -151.68
pounds.
Total chord load, L. L=+.15X 960 = 144.0.
Chord load, pound per square inch, H. I.= - .01804.
Chord load, pound per square inch, L. I.=+ .01712.
The stresses due to chord loads will be determined
and added to the stresses due to beam loads in order to
determine the maximum stresses.
It will be considered that only the box portion of the
wing will resist the bending moment due to chord loads.
The moment of inertia of the box section about its
FIGURE 6
minor axis will be computed and the
corners computed from the expression
293
stresses at the L-z= 12 [L23t+ .028] X(l 4.5)2[d1t1+d2t2+A4+As+A6
S
_My
- I
S=tensile or compressive stress.
y=distance from neutral axis to outermost fiber.
I =moment of inertia of section.
M = applied moment.
+ A1]= 2030[L23t+ .028]211[d1t1 +dzt2+1:Ap]
The neutral axis will be considered at a point midway
between the flanges. This will give the least moment
of inertia of the section and the error involved is small.
PURSUIT WING
Computation of moment inertia about short axis
Station _____ ------- _____ 1 2 3 4 5 6 7
--------- ------ - - ------
A1, rear ____ _______ ___ _____ ___ 0.187 0.187 0.187 o. 374 o. 374 0. 374 0. 374 .... '""------------------···1 0.187 0.187 0. 374 0. 374 0. 561 0. 561 0. 748
AA,s,, rfreoanrt- _-_-_-_-_-_--__-_-_-_-_-_-_-_- ----------- 0. 232 0.232 0. 232 0.232 0.232 0. 232 0 232 0. 232 0. 232 0.232 0. 232 0.232 o. 232 0. 232
d1t1, rear ______________________ 0. 050 0. 071 0. 089 0.163 0. 189 0. 212 0. 2-13
d2h, front ______ _______________ 0.111 0. 136 0.158 0.182 0. 329 0. 358 0.400
2'A ___ - - - - - - - - - - - - - - - - - - - - - - - - 0.999 1. 045 1.272 1. 557 1. 917 1. 969 2. 229
211 2'A----------------------- 210 220 268 328 404 415 470
"--------- ---- ------ ------ --- - 0. 016 0. 016 0.020 0. 020 0.032 0. 032 0.040
(J.23 ti+.028) _________________ . 0477 . 0477 .0526 .0526 .0673 .0673 . 0772
2030 (1.23 t.+0.28) ____________ 97 97 107 107 137
I
137 157
J _____ --- - - - - ----- - -- -- -- ---- - 307 317 375 435 541 552 627
Y/I (Y= l5~)- - ------ ----- --- 0. 051 0. 049 • 0413 .0357 .0286 • 0281 .0247
,
7
PURSUIT WING
Chord load shears and moments
HIGH INCIDENCE
, ___ s_tat_io_n----_--_--_---_- -_, _ o_ _______ 1 L_____ 2 1-------' 3 ------- 4 ------- 5 ------- 6 -------1 7
Distance from tip__ ___ ___ O ------- 28 ------- 55 ------- 80 ------- 105 ------- 130 --- ---- 150 --- - --- 177
D istance between sta-tion,
x _________________ ------ 28 ------- Tl - - ----- 25 25 -------- 25 ---- ---- 20 - --- -- -- Chord equivalent wing__ 16. 5 28 39 45. 6 52. 5 59 67. 3 27 - --------- 72
Running load, pounds
per inch ___ ________ _____ . 298 ------- 0. 505 ------- 0. 685 ------- 0. 842 ------- 0. 930 ------- 1. 065 ------- 1. 214 - ---- - - 1. 30
Mean load between sta-
L;:.dn_between--station:- --- --- , o. 102 --- ---- o. 595 ------- o. 763 ------- o. 886 -------- o. 991 -------- 1. 139 -------- i. 257 ----------
w ______ ___ _____________ ______ lL 28 _____ __ 16. 01 _______ 19. 08 _______ 22. 20 ________ 21. 90 ________ 22. 80 ________ 33. 90 _________ _
Total shear _______ _______ ----- - ------- 11. 28 ------- 27. 35 _______
1
46. 43 ------- 68. 63 ------- 93. 53 --- ---- 116. 33 --- --- - 150. 23
Moment SX_____________ 0 ------- 0 ------- 304 ------- 658 ------- 1, 160 ------- l, 715 ------- 1,875 ---- --- 3, 140
Moment~~------------ ______
1
158 ------- 217
1
_______ 238 ------- 277
1
________ 311 -------- 228 -------- 458 -------- - -
Total moment----------- 0 ------- 158 ------- 679 ----- -- 1.575 ------- 2,962 4,988 7,091 10,689
H. I. shear_______________ 0 ------- 135 ------- 328 ---- - -- 545 ------- 812 I, 125 ------- 1, 396 ------- I, 805
H. I . moment ___________ ------------- 1, 895 .--- ----1 8, 150 ------- 18, 900 ------- 1 35, 600 ------- 59, 800 ------- 85, 000 ------- 128, 100
LOW INCIDENCE
Running load, pounds I
0. 669 ------- 0. 781 - - - ---- 0. 900 --- - --- 0. 995 ------- L 152 ------- 1. 233
Mt~~~-~~~~-~-t:~~-~:~~- -- -- -- 0. 387 ------- 0. 579 ------- 0. 725 ------- 0. 841 -------- 0. 948 ------ - - 1. 073 -------- 1.192 ----- - ----
per inch ___ _____________ . 283 _______
1
0. 490
Lowad_ __b_e__tw__e_e_n__ _s_t_a_t_i_o_n_,_ _______ 10.83 _______ 15.62 _______ 18.13 _______ 2i.05 _____ ___ 21.10 ________ 2i.50 ________ 32.20 _________ _
Total shear _____ ___ ______ --- - -- ------- 10.83 ------- 26. 45 ------- 44. 58 ------- 65.63 - -- --- - 90.33 -- - - --- lll.83 -- ---- - 144.03
Moment SXX- --- ----- -- 0 ------- 0 ------- 292 ------- 637 ------- 1,117 -- ---- - 1,6.J.2 ------- l,807 ------- 3,015 wx Moment - 2 _________ ___ ---- -- 152 ------- 211 ------- 227 ------- 264 --- ----- 309 -------- 215 -------- 435 .------- -- -
Total moment__ __ _______ O --- ---- 152 656 1,520 2, 901 4,852 6,874 -------1 10,324
L. I. shear______ _________ o ------- 75 ------- 172 ------- 290 ------- 427 - ------ 587 775 --- - --- 936
L. I. moment ___________ - ----- - ----- - 989 ------- 4, 270 ------- 9, 890 ------- 18, 890 ------- 31, 550 ------- 44, 700 ------- 67, 200
PURSUIT WING
Stresses due to chord loads
Station ___ ________ - - - - - - - -- -- - - - - - - - - - - 2 4 5 6
Total area upper fiange______________________ L 065 1. 065 1. 215 1. 215 1. 665 1. 665
H. I. axial load----------------------------- -- 1, 830 6, 940 14, 630 24, 660 37, 250 48, 900
H. I. P/A------------ ------ --- --------------- 1, 720 6, 520 12, 050 20, 300 22, 400 29, 400
Y/I section____ ________ _______________________ . 051 o. 049 o. 041 o. 036 o. 029 1 o. 028
Chord moment, H . L-------------- -- -- ----- - 1, 895 8, 150 18, 900 35, 600 59, 800 85, 000
P/A due to chord load_ __ ___ __ ____ ____________ 92 400 775 1, 280 1, 740 2, 380
Total P/A F. U. flange, H. L---------------- 1, 812 6, 920 12, 830 21, 580 24, 140 31, 780
Allowable _ _____ ___ ____ __ ____________________ - ------------------- 23, 000 25, 000 29, 000 33, 000
L. I. moment________________________ ________ 5, 080 24, 000 59, 900 117, 600 199, 300 •
1
286, 500
Depths between centroids____________________ 5.14 6. 40 7. 56 8. 72 9. 89 10. 82
L. I . axial load---------------------------- - -- 990 3, 750 7, 920 13, 480 20, 150 26, 500
*ti~fEji?~\~~~~~~~~~~~~~~~~~~~~~~~~~i;;;;;~~~;; ;;;~~~~;; ~~~~~~~;~f-~~i~~~~~~~ ;;~~~~~~;;:;;;~~~-~~;;
(Reco=ended that an additional section of flange angle be adderl to the front upper fiange between stations 6 and 6'.)
PURSUIT WING Q.=K.AV2Xd.
1. 969
66. 300
33, 700
0. 025
128, 000
3,200
36. 900
36, 000
436,000
12. 12
36, 300
18, 450
67, 200
1, 630
20, 080
Investigation of nose-dive condition
K. =resultant airfoil vector = - .000039.
Assumed terminal velocity=350 miles per hour.
Assumed K.=resultant airfoil vector= - .000039
(approximately that of Gott. 398) when K.= .000.
Distance from elastic axis to wing vector approxi­mately
5.5 mean chord lengths.
The root moment will be calculated in terms of the
mean aerodynamic chord.
74602-31-- 2
A=one-half wing area=80 square feet.
V=velocity of dive=350 miles per hour.
d=distance from elastic axis to vector=5.5
X61.5.
0 ,=.000039 X80X350X 5.5X 61.5= 129,500 inch­pound
acting at the root of the wing.
Area of box section= l2.12X 29=352 square inches,
approximately.
/'
/ ,,
-
8
The shear stresses due to torque will be computed by LOWER COVERING
the expression
Here the principal stress will be tension and will be
double the value of the shear stress.
S=shear stress, pounds per square inch.
P=torque, inch-pound. t=0.014
A=cross section at area of section considered.
t=skin thickness at section considered.
129,500
TL. p.=352 x 0.014 36,800 pounds per square inch.
PURSUIT WING
Nose-dive condition
UPPER COVERING
t=sum of thicknesses of flange and outer corrugated
sheet=0.040+0.012=0.052 inch.
The allowable shearing stress on the upper corrugated
flange will be about 10,000 pounds per square inch,
hence the stresses due to torque are negligible for this
member.
129,500
Su. P· 2 X 352x0.052 =3,525 pounds per square inch
The allowable stress for the lower flange will be its
ultimate tensile stress of 55,000 pounds per square inch,
hence it is satisfactory.
PURSUIT WING
Weight estimate (one-half wing)
Item Amount Section and area
Upper fiange angJes ________ ______ 1{i~ ~~g~:::::::::::::::::::::::::::::
330 inches _____ ------ ______ ----- ______ _
Lower flange angles ______________ {75 inches _____________ ___________ _____ _
:::-<o. 1
No.3
No.4
No.5
No. 7
o. 231_ _____________________ _
0.157 ----- -- ---- ---- --------
0.214_ - - - - - - - - -- - - - - -- - - - - --
0.184 __ ------- -------- -- ----
237 inches ___________ -- -- -- _- - _- --- - - -- 0.114 __ - -- -- - - - --------- -- --
Webs:
Front _______ -- -- -- - -- - -·-- -- m~~~g~~= ::: ::::::::::: :: :::::::: :::: 0.020 x 8.60 _______________________ _
0.032 x 11.l __________ __ ________ ___ _
Rear ______ ---_ ------- -----_ -- {~~ ~~g:::::::::::::: ::::: :: : :::: :: ::: 0.016 "4.6 __________________ ___ ___ _
0.024 x 8.13 _______________________ _
Stiffeners:
Front web-
L_ ------------------ ---- 24 at 12 inches ____________ ______ ______ t=.024------- ----------- -------- ---
2. - - ----- ---- ---- -----·-· 48 at 10 inches _____________ ------------ t= .024----------------------------·
3. - - ----- ---------------- 96 at 8 inches-------------------------- t=.020 ___________________________ _
Rear web-------·--··-·-·-·-· 11x16 at 672 inches ___________________ t=.020--------------------------- -·
Unit weight
Pounds per
cubic inch
0.1011
.1011
.1011
.1011
.1011
Pounds per
square inch
. 00202
. 00324
. 00162
. 00242
. 00486
. 00363
.00303
• 00303
'l'otal
weight
Pounds
4.5
2.9
7. 2
1.4
2. 7
2.1
2. 5
. 7
1. 9
1. 4
1. 75
2.23
3. 5
Total .••.. -------·--·--· •••• -----------·-····-······-·-·-----·-- ...•.••••...••.••.•••••••••.•....•..•• ____ ___ . ---- 34. 8
Corrugated upper fiange: L- -------- ------ -- --------- - 29 inches ___ ___ ______ __________________ Flat width 36 inches t= .040 _____ _
2-------- -------------------- 44 inches __ ____________________________ Flat width 36 inches t=.032 ..••••
3---------------------------- 46 inches. _______________________ ______ Flat width 36 inches t=.020 ..... .
4------------------- --- ------ 51 inches . . --------------------------- - Flat width 36 inches t= .016 .•.•..
.00404
. 00324
.00202
. 00162
4. 22
5.14
3. 35
3.00
'l'otal, corrugated fiange_ -----·------ ---- ---·-------------------- ---------------------------·-------· ------- ------- 15. 71
Corrugated covering, front web
to trailing edge: L--------------------- ------ 58 inches ___ ___________________________ Flat width 36 inches t=.012 __ ___ _
2 __ _________________ _________ 56 inches __ ______ __ ____________________ Flat width 36 inches t=.012 _____ _
3- - -------------------------- 53 inches ______________ ________________ Flat width 36 inches t=.012 _____ _
45------·------------------------------------------------- 50 inches .. --- - - - - --- ----- - - -- -- - - - - --- Flat width 36 inches t-.012 _____ _ 48 inches _______ ____ __ ______ ______ __ ___ Flat width 50 inches l=.012 _____ _
.00121
.00121
. 00121
. 00121
. 00121
2.5
2.4
2.3
2. 2
2.9
'l'otaL .. - - - --------- --- - -- - ------ --- ----. _ --- --- ---- .... ________ ------ ------------------- --- · ------- _____ ------ --- 12. 3
Leading edge _______ ____ _________ 166 inches _______ ____ ___ ___________ __ __ Width 25 inches l= .020_ - - -- - - ---
Spar, L. F ___ _______ ___ _______ ___ 90 inches __ _____ ________ ______ ____ _____ Widih 30 inches l=.014- _____ ___ _
Spar__ ______ ________________ _____ 7i inches ___ ______ __________ ________ ___ Width 30 inches t=.014- __ __ ____ _
Trailing edge. ______ ___ __ ________ 166 inches ____ ___ __ _________ ___ ______ __ Width 22 inches t=.014- ___ _____ .00202
.00141
. 001413
. 001413
8.4
3.8
3.3
5. 2
Total, lower covering ___ - - --- - - - - - - - ------ ---- - - - - - - - -- - --- --- - - --- --------- -·-------------------------- - ------ --- 20. 7
Wing tip __ -- ------ - - - - - - - - --- -__ 3,000 square inches, approximately ___ --- - - - - -· · - ------------------ - -- ---- . 001413 4. 3
I
Con~rol rods, ail, cranks, etc ________ __ _______ ____ _____ _____ _____ - - --- ----- ____ - - ---- - - --- - ------ -- ---- - --- ____ ----- ------- -- 6
Aileron horn, spar and false spar, hinges (aileron cover included in main coverl ------ ----- - - --------------------------------- 4
Miscellaneous fittings, wiring, etc. ______ ------ - - - - ---- ---- - - - ----- - ----- ____ __ ---- -- -__ - - - -- - ------------------ ______ ------ 12
Total __ - -_ - __ - - - -. ______ ____ -- - ____ . __ . _. - - - - - - - - - - - __________ ---- __ - - -- - _. ____ ___ ______ __________ . ___ ___ ___ ------ 22
PURSUIT WING Total weight, one-half wing_____ ___ 136.8 pounds.
Area, one-half wing ______________ _ 80 square feet.
Total weight (one-half wing) less Dead weight of wing __ __ __________ 1.71 pounds per
ribs ____ ____ ____ __ ___ __________ 109.8 pounds. square foot.
Ribs at 25 per cent of weight less 1.lOX dead weight __ __________ ____ 1.88 pounds per
ribs __________ .... __ .. _. _______ 27 pounds. square foot .
II. ATTACK WING
Gross weight of airplane ___________ 5,0GO pounds. 108+53 75
Wing area, total __________ ________ 304 square feet. Area, GHEF' 2 . X186= 15,043 square
Estimated unit weight of wing_____ 1. 7 5 pounds per inches.
square foot. Area, EF'AB'=28+
2
53.75X76=
Estimated total wing weight_______ 532 pounds.
3,106 square
Weight less wings _________________ 4,468 pounds. inches.
Thickness ratio chord,
11.76) = 11.76-0.87=10'.89.
31
AB=ll.76-231 (18.46-
Total_ - -------- ____ - -- ______ 18,149 square
Thickness ratio chord,
11.76) = 11.76+ 1.30= 13.06.
45
EF=ll.76+ 231 (18.46-
inches.
Computation of loading-
15,043W +0. 915X3106W = 2,234 pounds.
15,034W+2842W=2,234 pounds.
17,885W=2,234 pounds.
I
Equivalent chord, A'B'=i~:~~X47.5=2 .0 inches.
W=0.1249 pounds per
square inch.
Eq m. va1 e nt c h ord , E'F' = l3.05 · 18.46X76=53.75 mches.
18 i-------------Z64 __________ -J
44
108
G
-L-4----1- Rear web
Of airplane
--
53.75
75
J
FIGURE 7.-Attack wing
(9)
----- 75 ----i
E c
--
4
+
31
IJ
Per cent
chord
Distance
along
chord
R oot
Chord=l08 inches
Ordinates
Upper
10
ATTACK WING
Airfoil ordinates
Lower
Distance
along
chord
Tip
Chord=67).i inches
Ordinates
Upper Lower
I Per cent Inches Per cent Inches
1
Per cent I Inches Per cent Inches
--0----.-0 -1~~~~,-oo--~~~~
l'A 1.4 8.09 8. 73 1. 62 l. 75 0. 85 5.15 3.48 1.03 0.69
2 ~ 2. 7 9. 54 10. 30 l. 00 l. 08 l. 70 6. 11 4. 13 0. 63 0. 42
5 5. 4 11. 81 12. 76 0. 46 0. 50 3. 37 7. 52 5. 07 0. 28 0. 19
7 ~ 8. l 13. 58 14. 65 0. 22 0. 24 5. 06 8. 65 5. 85 0. 14 0. 09
10 10. 8 14. 85 16. 02 0. 10 0. 11 6. 75 9. 45 6. 38 0. 07 0. 05
15 16. 2 16. 60 17. 91 0 0 10.12 10. 56 7. 12 0 0
20 21. 6 17. 73 19. 15 -- -- ------ - -- ------- 13. 50 11. 28 7. 60 ---- ----- - ----------
30 32.4 18.46 19.90 - - - - ---- -- ------- -- - 20.25 11.76 7.84 -- --- ----- --- - ------
40 43. 2 17. 89 19. 30 ---- -- ---- ---------- 27. 00 11. ·12 7. 71 - --- ------ ----------
50 54.0 16. 21 17. 50 --- ----------------- 33.75 10.33 6.60 - -- - --- --- ------ ----
60 64.8 13.83 14.92 - -- ------- ------- - -- 40.50 8.81 5.95 ---- ------ -------- --
70 75.6 11.ll 12.00 -------------- --- --- 47. 25 7.08 4.78 - ---------- ---- -----
80 86.4 7.88 8.50 -------- -- ---------- 54.00 5. 02 3.39 ---- -- -- ------ --- ---
90 97.2 4.31 4. 65 ----------·---- - - -- - 60.70 2.72 1.84 ----- ----- --- --- - ---
95 102. 5 2. ~9 2. 58 - - --- - ---- ----- ----- 64.10 1. 50 l. 00 - - -------- ----------
100 108. 0 0. 43 o. 46 -- --- - - - - - ---------- 67. 50 0. 25 0. 17 - --------- -------- --
ATTACK WING
Load distribution factors
Station. _______ ___ ___ __ ____ __ __ - _____ - - - _ 2 3 4 5 8
------------------ ---
Distance from tiP------------------ ------------ 0 44 75 107 138 169 200 231
Aetna! chord . . _- -- ---------------- -- - --------- 67. 5 75 80. 7 86. 3 91. 7 97. l Hl'l. 6 108
Distance LE-CP 31 per cent ____ ___ __ _________ 20.92 23. 23 25. 00 26. 77 28. 44 30.11 31.80 33. 50
Distance LE-CP 52 per cent ______________ ____ 35. 10 39. 00 42.00 44. 90 47. 70 50.50 53.30 56. 10
Distance LE-FS. --- --------- - ---- -------- ____ 7. 50 10. 07 11.88 13. 75 15. 56 17. 36 19.19 21. 00
Distance LE-RS._--------- --------- ------ --- - 51. 50 54.07 55.88 57. 75 59. 56 61. 36 63. 19 65.00
Distance CP 31 per cent-RS __________________ 30. 58 30.84 30.88 30.98 31.12 31. 25 31. 39 31. 50
Distance CP 52 per cent- FS ___________________ 27. 60 28. 93 30.12 31.15 32.14 33. 14 34. 11 35. 10
FS distance factor, H. r_ ____ ___ _____ ____ _____ __ 0.695 0. 702 0. 703 0. 704 o. 707 0. 711 0. 714 0. 716
RS distance factor , L. !_ ______________________ 0.628 0.657 0. 685 o. 708 o. 730 0. 753 0. 775 o. 797
FS distance factor X LF, H. I.. ---------- -- --- 5. 90 5. 97 5. 97 5. 98 6. 01 6.04 6. 07 6.07
RS distance !actor X LF, L. L ______ ________ __ 3.45 3. 61 3. 77 3. 89 4.02 4.14 4. 26 4.38
x Aetna! chord=67.5+
231
(40.5)=67.5+0.1754X.
Distance LE to l!'S=7.5+:i (13.5)=7.5+0.0584X.
ATTACK WING
Shears and moments
Station ______ _____ _____ __ ___ 0 --- 2 I --4-----·1---- 1---·1---6--1---11---7--1---·1---8---1
Distance from tip ___ ____________ ------------------------------------------------------------------------------------------------------------------------------------- -- -------------- ----------------- -
Chord, cqnivalent, wing________ 28 -------- 38. 65 -------- 53. 75 ---- - --- 63. 04 - --- ---- 72. 00 -------- 81. 00 - -- ------ 90. 00 -------- - 99. 00 -- ------- 108. 00
Distance between station, X ____ -------- 31 -------- -- 44 ------ ----- 32 ----- -- --- - 31 - ----- ----- 31 --- -------- 31 ----- --- ----- 31 ------------- 31 ------- ----- -
Running load, pounds per inch. 3. 49 -------- 4. 83 -------- 6. 71 -------- i. 86 - ------- 8. 99 -------- 10.10 -- ------- 11. 24 --------- 12. 35 - -------- 13. 48
Mean running load between ·
L;~dt~et~~~~1:tf~~.1!!.c~-:_-~::: :::::::: \~~ :::::::::: 52~b ::::::::::: 72~~ ::::::::::: 82~~ ::::::::::: 92~1 ::::::::::: 108g~ ::::::::::::· 11 3~~ ::::::::::::: 123~! ::::;::::::::
Total shear, S-------- ------- --- -------- -------- 127 377 607 864 1, 155 1, 480 1, 840 2, 234
Moment SX------------------- -------- -------- 0 5, 690 12, 070 18,820 26, 800 35, 800 45, 900 57, 000 x Moment w 2 ---------- -- ------ -------- -------- 1, 970 5,500 3, 680 3, 980 4, 510 5, 040 5, 580 6, 110
Total unit moment_ ____________ -------- -------- 1, 970 13, 160 28, 910 51, 710 83, 020 123, 860 175, 340 238,450
H. I . moment_ _________________ -------- -------- 16, 750 111, 800 247, 500 440, 000 705, 500 l, 051, 000 l , 490, 000 2, 030, 000 I. F. moment _______ ____________ -------- -------- 6, 900 46, 000 101, 200
1--------
181, 000 291, 000 i--------- 433, 000 614, 000 835,000
FS distance factor ____ ___ _______ -------- -------- 5. 90 5. 97 5. 97 -------- 5. 98 6. 01 --------- 6. 04 6. 07 6. 07
FS shear, H. L-- --------------- -------- -------- 750 2,250 3, 622 5, 160 6, 945 8, 930 11, 180 13, 560
RS distance factor ______________ -------- -------- 3. 45 3. 61 3. 11 1:::::::: 3.89 4. 02 1--------- 4. 14 4. 26 4. 38
RS shear, L. L _________________ -------- -------- 439 l, 360 2, 290 3, 360 4, 650 -- ---- --- 6, 130 7,850 9, 790
1 Correction factor 0. 985 to allow for trapezoidal shapo of load. f-l
f-l
Station_----- ______________ __ -----
DShiesatar,n cHe .f rIo. mpo sutnadtiso _n_ _L__--_-_-_-_-_-_-_-_-_-__-_-_- -_
Depth between flange centroids _______ _
t, required ______ ----- ____ . - --- --- - -- - --
Recommended gage _________________ _
Shear, L. I. pounds ______ ________ _____
Depth, centroids. _------------ ---- - - --
t, required _____ _______ -------- - - -- -- ---
Reco=ended gage ___ ________________
0
750
5
.005
. 016
439
. 028
.008
. 016
12
ATTACK WING
Design of webs
FRONT WEB
2
44
2, 250
7. 29
. 0112
. 0160
75
3, 622
8.90
. 0148
. 0160
REAR WEB
1, 360 2, 290
3. 71 4. 92
. 0133 .0169
. 016 .024
4 5
107 138
5, 160 6. 945
10. 57 12. 17
. 0178 . 0207
. 024 .024
3,360 4,650
6. 17 7. 31
.0198 .0230
.024 .024
Depth between centroids, front web=5+ 2-fi X12=7+0. 0519X.
. 9
Depth between centroids, rear web=2+231 X=2+o.0389X.
ATTACK WING
Design of vertical stijf eners
6 8
169 200 231
8,930 11, 180 13, 560
13. 79 15. 39 17. 00
. 0235 .0264 .0290
.032 . 032 .032
6, 130 7,850 9, 790
8. 58 9. 79 11. 00
. 0257 . 0291 . 0324
.032 . 032 . 032
1
____s_ ta_t_io_n_._-_-.-_-_-_--_-_--_-_-_--_-_-_---_-_--_-_-__
11
___- 1_ _ 2_ ____3 _ ____4 _____5 _ ____6_ ____1 _ _j _ _8 _ _
Shear, 1''. W., H. !_______ ____ _____ ___ __ 750 2. 250 3, 622 I 5, 160 6, 945 8, 930 11, 180 13, 560
Depth between centroids___ ___________ 5 7. 29 8. 90 10. 57 12.17 13. 79 15. 39 17. 00 I Rib spacing________________________ ___ 21 21 19 19 17 17 15 15
Stiffener spacing____ ___________________ 10. 5 10. 5 9 50 9. 50 8. 5 8. 5 7. 5 7. 5
Load on stiffener___ __ _______________ __ 1, 575 3, 240 3, 850 4, 650 4, 850 5, 550 5, 450 5, 980
4t~~~~i~~t:o112:::::::::::::::::::: : 8~~ : 5g~ : ~~ : ~5 : ~ : 5;g : 5~ : ~~ I
Area section'-------------------- ------ .192 .192 . 240 . 240 . 300 • 300 . 300 • 300
Shear, R. W., L. L------------------- 439 l, 360 2. 290 3, 360 4, 650 6, 130 7, 850 9, 790
Depth between centroids______________ 2 3. 71 4. 92 6.17 7. 31 8. 58 9. 79 11. 00
Stiffener spacing_ ______________________ 5. 25 5. 25 4. 75 4. 75 4. 50 4. 50 4. 50 3. 75
Loadon stiJiener- - ---- ------------ ---- 1,150 1,925 2,210 2,590 2,700 3,035 3,610 3,330
Area required•- -- ---- - - ------ - --- ----- .057 .096 . 111 .130 .135 .1520 . 1805 .1665
Thickness section'--- -- --------------- .020 .020 .020 .024 .024 .032 . 032 .032
Area section•--- ----------------------- .120 . 120 . 120 .144 .144 .192 . 192 . 192
• Allowable P/A taken at 20.000 pounds per square inch on •,4 by ;1-4-incb 1mg\es rivet-0d to the webs.
2 4, 3,f hy 3{-inC'h, angles are corn~idcred n." contprP.ssing a stiffener.
ATTACK WING
Design of upper flange, H. I.
Station _____ ______________________ _____ _ 2 3 5 6 8
Depth between ccntroids ____________ inchrs__ 6 8. 29 9. 90 11. 57 13.17
~foment, tr. !_ ________ ________ __ inch-pound __ 16, 750 I I 11, 800 247, 500 440, 000 705, 500 I, 051, 000
14. 79
71, 100
15
l, 490, 000 2, 030, 000
Axial load _________ _____ _____ ___ _____ pounds__ 2, 790 13. 500 25, 000 38, 000 53, 500
~if:{;fi1!n~1i=~~~=i~~~::::::::::::::~~~~:: ::::::::::!:::::::=::: ::::::::::: 34, Jg ~8 Total area required ____________ square inches ___ _____ ____ ----------- 1.09 1.46
34!~
~~~~:~,s;~~·- ~~~~~~-~!~~:::::::::::::::::::: ::::::::::1:: ::::::::: ---- -~oi:i-- ?o~ -----~022--
Actua1 gage_________ _____ _____________________ . 016 . 016 . OlG • 020 . 024
R/t_ ________________ ---------- ------- --- ----- ---------- ----------- ---------- - ----------- -----------
;[!~~n~:fe~ffc~i-o~:::::::::::::::::::::::::: :::::::::: ::::-:::ii;~~~:::::::: ___ :~~~--!---~~~--
Section No. 2 area of "8-inch flange angles=0.62 square inch.
Depth=6+0.0519X.
Radius of currnture=0.675 inch.
p=0.269 incb
0=3.
16. 39 18
91' 000 112, 800
15 15
56 5G
35, 000 35, 000 35, 000
2. 16 2. 52 3. 22
1. 52 1. 88 2. 58
. 025 • 0336 . 046
. 02312 ________• 0_5__0 __ .1 035. 0 5 I
33, ()()() -- ----------- 39, 000
2. 4f No. 2 3. 42 -------~~~--!
X =dis ta nee in inches
from station. Flat width of sheet=44XL23+2=56 inches.
Corrugated arca=56Xt.
13
· ATTACK WING
Design of lower flange, I. F.
Station ______________ ____ _______ ______________ __1_ ___2_ _ 1 3 4 6 7 8
Depth between centroids ___ ___ ___ __________ inchcs.. 6 8. 29 9. 90 11. 57 13.17 14. 79 16. 39 18
I. F. mi:iment ____ _____________________ inch-pounds.. 6. 900 46, 000 101, 200 181, 000 291, 000 433, 000 614, 000
I. _F. !'xial_ load __ ___________ ________________ pounds__ l, 150 5, 550 10, 200 15, 080 22, 100 29, 100 37, 500
835, ()()()
D1stnbut10n factor_ ___ ________ __ ____________________ . 695 . i02 . 703 . 704 . 707 . 711 . 714
46, 300
. 716
Axial loo.ct, FL flange _______________________ pounds.. 800 3, 860 7, 180 Jl, 100 15, 600 20, 700 26, 800
Axial load, RL flange ___ _____ ____ ___ ____ _____ do.... 350 1, 690 3, 020 4, 580 6, 500 8, 400 10, 700 33, 200
Allowable P/A taken at 25, 000 pounds per square inch
13, 100
Area required, FL _______ ___________ square inches ..
.Area required, RL ____________________________ do ....
Section FL .. ------ ______________ ________ ------------
.032
.014
.154 .297 .443 .624 .828 1.07 1. 33
. 067 . 121 . 183 . 260 • 330 . 428 . 524
1 li8 { 1l l•i8 } 2l.i8 { 12li•8 12;r•s 2 li8
Total area, FL ________ ______________ square inches .. 1.
11110
.190
1 illO
.190
1 #7
.380 . 699 I . 760 1. 076 1. 076 1. 392
Section RL ______________ ____ ________________ ______ _ 2 #4
Total area, RL ______________________ square inches __
lW
.114
1 ~. 12 { 1 ~7 1 W4 1 #4 } 2 ~,
" 1 #12 ] #'4 1 #12 tp { 1 #11
.114 .146 . 260 . 300 . 360 .428
ATTACK WING
Weight estimate (one-half wing)
Item Amount Section and area
Upper flange angles _____________ {285 !nches ___ __________ __________ ____ __I No.
250 mches.------------------- --------- No.
2 o. 310 ________ ___ ___ _______ _
a 0.157.. __________ __ _______ _
Lower flange angles:
{
284 inches __ __ _________ ----------------
Front 190. inches·-------------------------- --
··---------- --- ------ --- 80 mches. ___ ----- ----- ___ . _ --· - - ------
126 inches •.••..• -- •• ____ -- _____ ____ __ _
Rear _ • _____ ___ ••• ______ _____ {!~~!~gt~:::::::::::::::::::::::::::::
No. 8
No. 9
No.10
No. 4
No.11
No.12
No. 7
o. 380 ____ ___________ ___ ----
00.. 311960 ._._ ___________________ _-_-_-_--__-_-_-_- -_
o. 214 ____ ____ __ ___________ _
o0..1 04968 •.•. •_•_ -_-_-_-_-_-_-__-_-_-_-_-_-_-_--_-_ -_
0.114 ______ ____ ___________ _
Unit weight
Pound• per
cubic inch o. 1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
. 526
Total
weight
Poundt
8.9
4.0
10.8
6.0
1. 5
2. 7
0.3
1.8
0.8
Total.---- -- ----- --- --- ------- --- --- ----- ------. -- -- • -- --- ----- ------ -- ----------- --- -- --- -- -- . ---- ------ ---- ---- 36. 8
I
We~:ont ________________________ {gn~~r~~:::::::::::::::::::::::::::::I 8: g~~ ~ 1~: L::::::::::::::::::::: : mu ~: ~
L. ::::::~·~~:·--···~~~ i:~::~·~~:~··~~~·~~~~·~~~~~~~i-~~~~~~·~·~~~~~~~~~~·~~~·~~ -. ::~~ -:~ ~
{
100 inches.------------ ··-------------- 48 x. 020 .•••. ------------ -- -------- .1011 9. 6
Lower skin 84 inches---- ---- ------- -- ------------- 48 x. (}76 .•••. ----'------- --- - ------ .1011 6. 2
··---------- ---------- 230 inches------- ---------------------- 24 x . 016 ••••. ----- -- --------------- . 1011 8. 9
213 inches.---------------------------- 18 x. 012_________________ __________ .1011 4. 6
Total.. -------------- __ --------------- .•• ---- --- -------- -- ----- _ ------- -------- ------ --------- --- -- ----- -------- - 29. 4
Stiffeners:
Front web •.. ----------------{r~!A~l~!~~::::::::::::::::::::::::: 1:: ~~::::::::::::::::::::::::::: : rnn n
: :~~··~:::·::-•-•••1!!:·::~~~=~·~~·~·~~~~~~·~~~,~~~~~-: :~~~:~~~~·~··~~~·~~·~~·~~·=~=~~ ::::::•l!ll:: ,! l Aileron control rods, cranks, etc ______ ------ -- -------- ---- - - --- ---- -- ---- ------- --- ---- --- ------ -- -- - -- ----- -- -- ---- - ----- --
tf~~~N!~~':isf~;tt;.~::' ~~~::I>~~iecti ve-co~iti;g; etc===:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Total. ____ .•. --.............•..... -- -- . - - - -. - - - - - - - - - - - - - - - - - - - - - --- - - - -- - - - - - - - - - - - - - - - - - - - - - - - -- - - -- - - - - - - - - - - - -
Corrugated flange:
55 x 80 inches (1 sheet) ____ ___ _________ t=.016 (2J+inch pitch) ___________ _
55 x 32 inches (1 sheet)_--------------- t=. 020 (2)1i-inch pitch) ____ _______ _
55 x 32 inches (1 sheet)_-------- ------- t=. 024 (2)1i-inch pitrh) ___________ _
55 x 32 inches (1 sheet)_--------------- t=. 032 (2!1i·inch pitch) _____ __ ____ _
55 x 65 inches (1 sheet)_--------------- t=. 050 (2)1i-inch pitch) ___________ _
.1011
.1011
.1011
• IOU
.1011
10
6
15
31
7.0
3. 5
4.3
5. 6
17. 9
Total. ___ ------------ - - --------------- ------------------------- ---------- ------ ---- --- ------ ------- -- -- -- -. ------ 37. 3
30
Corrugated cover:
36 x 82 inches (7 sheets)________________ t=. 012 (lU-inch pitch). ____ ______ _ .1011
Total dead weight less ribs, one-half wing------------------------------------------- ---------------------------------------- 218
Ribs, 25 per cent of 218 pounds---------------------------------------------------------------------------------------------- 54. 5
Total dead weight, one-half wing __ _______________ .• -- ------------ - --- ------- - - ----- - - --- -- -------- •. ------ ------- 272. 5
Area, one-half wing, 152 square feet.
Unit dead weight, 1.79 pounds per square foot.
1. lOXdead weight, 1.97 pounds per square foot.
III. TWIN-ENGINED OBSERVATION WING
EFFECT OF NACELLES, GAS TANKS, LANDING
GEAR, ETC.
The weight of the engines, nacelles, landing gear,
tanks, etc., will arbitrarily be taken at 35 per cent
gross weight, and will be considered as acting 85 inches
from the center line of the airplane.
The center of gravity of the nacelle group will be
considered forward of the front spar a distance sufficient
to increase the front spar reaction 15 per cent and cause
a -15 per cent reaction on the rear spar.
Lacking detailed design features, the entire wing
area from the tip to the side of the fuselage will be
considered as effecti:ve, that is, no allowances for areas
covered by nacelles.
Since this type of airplane will not be subject to the
severe diving conditions of the pursuit and attack
types, the most severe torque condition will be taken as
low incidence.
35
Thickness ratio, section 0=11.76- 265x (18.46-
11. 76) = 11.00 per cent.
Thickness ratio, section 3= 11.76 - ~~·: x (18.46-
11.76) = 13.47 per cent.
Chord, station 0=i~:~~X 67=39.9 inches.
Chord, station 3=i~:!~ x 102.5=74.7 inches.
Area of equivalent wing-
A.= (65X 144) + 19~· 5 (144+ 74.7) +
10
;·
5
(74.7
+39.9).
A.=9360+21596+5873=36,829 square inches.
Gross weight of airplane=8,000 pound .
Estimated wing weight at 1.75 pounds per square
foot= 1,000 pounds.
Net weight per wing= ( 8,000-1,000H~=3,500
pounds.
TWIN-ENGINED OBSERVATION WING Loading over equivalent wing= W
31316W +0.9X5873W =3,500 pounds.
31316W +5286W =3,500 pounds.
36602W = 3,500 pounds.
Per cent
Thickness ratio, section!_ ___________________ 11. 76
Thickness ratio, section 7 ____________________ 18. 46
6. 70
365
zo 65 _,front web
• Rea..r web
144-56
l~---
---
W=0.0956 pound per
square inch.
tauiV~ ---'-==-+-::~~~
...L_-1-_j_ ___ ~L,....::-:::::::..--~- ~ 102.5---'
t Nacelle 3roup
!Airplane
FIGURE 8
(14)
Per
cent
chord
0
1\4
2)-i
5
7)-i
10
15
20
30
40
50
60
70
80
90
95
100
Distance
along
chord
0
1.8
3. 6
7. 2
10. 8
14- 4
21.6
28.8
43. 2
57. 6
72.0
86. 4
100.8
115. 2
129.8
136. 9
144- 0
15
TWIN-ENGINED OBSERVATION WING
Airfoil ordinates
Root
Chord=l44inchesatstation 7
Ordinates
Upper Lower
Per cent Inches Per cent Inches
4. 33 6. 24 4. 33 6. 24
8. 09 11. 65 l. 62 2. 33
9. 54 13. 70 1.00 1.44
li. 81 17.00 0.46 0.66
13. 58 19. 70 0. 22 0. 32
14. 85 21. 35 0.10 0.14
16. 60 23.90 0 0
17. 73 24- 95 ---------- ----------
18.46 26. 55 ---------- ----------
17. 89 25. 70 ---------- ---------- 16. 21 23. 35 ---------- ----------
13. 83 19. 90 ---------- ---------- 11.11 16. 60 ---------- ----------
7. 88 11. 35 ---------- -------- --
4- 31 6. 20 ---------- -------- -- 2. 39 3. 45 ---------- 0.43 0 ::::::::::1
CJ8
.9 r-
Distance
along
chord
0
1.10
2. 20
4. 40
6.60
8.80
13. 20
17.60
26.40
35. 20
44.00
52.80
61. 60
70. 40
79. 20
83. 50
88. 00
Tip
Chord =88 inches at station l
Ordinates
Upper Lower
Per cent Inches Per cent Inches
2. 76 2. 43 2. 76 2. 43
5. 15 4. 57 1. 03 0.90
6. 11 5.38 0.63 0.55
7. 52 6. 61 0.28 0. 25
. 65 7. 61 0.14 0.12
9.45 8. 31 0. 07 0.06
10. 56 9. 30 0 0
11.28 9. 91 ---------- ---------- 11. 76 10. 35 ---------- ---------- 11. 42 10. 05 ---------- ----------
10. 33 9.10 ---------- ----------
8. 81 7. 75 ---------- ---------- 7.08 6. 23 ---------- ----------
6.02 4. 42 ---------- ---------- 2. 72 2.39 ---------- ---------- l. 50 l. 32 ---------- ---------- 0.25 0.22 ---------- -- --------
~sj
~ w
_._,_t-=-~-+~~~~-+~~~~-=::,.,_L
30----.~---- 56
i-------------~ 14~---------------
FIGURE 9
TWIN-ENGINED OBSERVATION WING
Load distribution factors
Station _____ _______________ - --- ____________
l 2 3 4 5 6 7 8
---------------------
Distance from station L----------- --- - - -------- 0 35 67. 5 117. 5 167. 5 217. 5 265 330
Actual chord-_------------------- -- ----------- 88 95.4 102. 5 112.8 123. 4 133. 9 144 144
Distance LE-CP 31 per cent _______ ___________ 27. 0 29. 5 31.8 34- 9 38. 2 41. 5 44_ 6 44- 6
Distance LE-CP 52 per cent ___ _______________ 45. 7 49. 6 53. 4 58. 7 64- 3 69. 7 75.0 75. 0
Distance LE-FS ____ ---------------- ---------- 9.0 11.8 14. 5 18. 2 22.5 26. 2 30. 0 30. 0
DDiissttaannccee 3L1E p-eRr Sc_en--t -t-o- -R-S-- -_-_-_--_-_-__-_-_-_-_-_--_-_-_-__-_-_- 65. 0 67.8 70. 5 74. 2 78.5 82. 2 86. 0 86.0 38.0 38. 3 38. 7 39. 3 40. 3 40. 7 41. 4 41.4
Distance 52 per cent to FS __________________ __ 36. 7 37.8 38.9 40. 5 41.8 43.5 45.0 45.0
FS distance factor, H. I. and I. F ______________ . 678 .684 .692 . 702 . 720 • 727 • 739 . 739
RS distance factor, L. !_ ____ ________ ___________ . 656 .675 .695 . 723 . 746 . 777 . 804 .804
FS distance factorXLF, H. !_ _____ __ __________ 5. 76 5.81 5.88 5.96 6. 11 6. 18 6. 28 6. 28
RS distance factorXLF, L. L----------------- 3. 61 3. 71 3.82 3.98 4.10 4- 27 4- 42 4. 42
x Actual chord=88+
265
(144-88) =88+0.2115X to station 7.
Distance LE to FS-9+ ;~ X =9+0.0793X to station 7.
TWIN-ENGINED OBSERVATION WING
Basic shears and moments
Station _______ -------- _____ _ 0 2 4 5 6 7 8
, ____________ , __ ----------------------1----1---1-----1----1------1---
Distance from tip _________________ 0 35 -------- 70 -------- 102. 5 -------- 152. 5 ·------- 202. 5 252. 5 300 365
Distance between station, X ______ -------- 35 ---------- 35 ---------- 32. 5 ---------- 50 --- -- ----- - 50 ----------- 50 --- - - -------- 47. 5 -- ---- - ------ 65 -------------
Cbord. equ!valent wing __________ 30.9 -------- 51.8 ----- --- 63. 7 -------- 74.7 -------- 92.3 -------- 109.8 --------- 127. 4 -- ------- 144 --------- 144
Running load, pound per inch____ 3. 05 -------- 4. 33 -------- 5. 68 -------- 7. 14 -------- 8. 81 -------- 10. 49 --------- 12. JS --- ------ 13. 78 --------- 13. 78
Mean running load between sta-tion,
pound per inch. _____ ______ -------- 3. 69 ---------- 5. 00 --- - ----- - 6. 41 ---------- 7. 98 ----------- 9. 65 -----------
Load between station, w _________ ,__ ______ 130 ---------- 176 ---------- 210 ---------- 402 ----------- 487 -------- ---
Total shear, 8-------------------- -------- ----- --- 130 306 516 918 1, 405
Moment sx _____________________ I ________ -------- 0 4, 550 9, 960 --------1 25, 800 45, 900
Moment w {---· --------------- '- ------- ----·--- 2, 270 3, 080 3, 420 I 10, 050 12, 190
11. 33 ------------- 12. 98 ------------- 13. 78 -------------
573 ------------- 622 ------------- 902 -------------
~ m ~a ~a
70, 250 94, 000 169, 000
14, 350 14, 150 29, 300
Total unit moment---- --- ------- -i- ----- -- -------- 2, 270 9, 900 23, 280 59, 130 117, 220 201, 820 309, 970 428, 645
H. I. moment _____________ ____ ___ ---------------- 19, 300 84, 100 198,000 503, 500 096, 000
I. F. moment·--·---- ---- ---------------- --------- 17, 950 34, 600 81, 500 207, 000 410, 000
FS FS sdhisetaarn_ c__e_ _fa_c__to__r_, _H__. _L__-_-_-_-_----_- 1---------------- ---------------- 5.7 5706 1,5 .7 8718 3,5 .0 8385 5,5 .4 7906 8,6 .5 9101
RS distance factor, H. L - -------- -------- -------- 3. 61 3. 71 3. 82 3. PS 4.10
RS shear--------------- ---·------'-------- __ ------ 470 1, 136 1, 970 3, 655 5, 790
1, 713, 000 2, 635, 000 3, 640, 000
705, 000 1, 085, 000 1, 498, 000
6.18 6. 28 6. 28
12, 220 16, 320 21, 980
4. 27 4. 42 4. 42
8, 450 11, 500 15. 480
fo-"
O')
17
CORRECTION DUE TO NACELLE Rear web, L . !.-Continued.
Weight of nacelle group=0.35X3,500=1,225 pounds.
Correction to BM at station 8:
Shear inboard of station 7, rear= 12,510 pounds.
Shear outboard of station 8, rear= 16,490 pounds.
Decrease in BM= l,225 X65=79,625 inch­pounds.
TWIN-ENGINED OBSERVATION WING
Net BM station 8=508,270-79,625=428,645
inch-pounds.
Front web shear correction, H. I.:
Shear due to nacelle= 1,225 pounds.
Total shear, front web, station 7, due to Nacelle
= 1,225X 1.15 X8.5= 11,980 pounds.
Shear outboard of station 7, front= 16,320
pounds.
FIGURE 10
Shear inboard of station 7, front =4,340 pounds.
Shear outboard of station 8, front= 10,000
pounds.
Depth between centroids at root=24 inches.
Depth between centroids at tip=6 inches.
Depth between centroids between stations 1 and 7-
Rear web, L. I.:
Shear due to nacelle=0.15X5.5Xl,225=1,010
pounds.
Shear outboard of station 7, rear= 11,500 pounds.
18
= 5+265 d.
= 6+0.068d.
TWIN-ENGINED OBSERVATION WING
Design of upper flange
Station_._ ••.•.•..• _. _____ • __ •••.•.•.•••.. 2 3 4 5 6
Distance from station 1------------------------ O 35 67. 5 117. 5 167. 5 217. 5
Depth between centroids____ __________________ 6 8. 38 10. 59 14. 00 17. 40 20. 75
Bending moment, H. L .------------------ ---- 19, 300 84, 100 198, 000 503, 500 996, 000 1, 713, 000
Axial load ••• ---------------------------------- 3, 220 10, 040 18, 740 35, 900 57, 250 82, 600
Rib spacing·----------------------------------------- - ------------ 18 18 18 18
~covering ___ ______ ________________ _____ _______ -------------------- 67 67 67 67
Allowable P/A covering_-- ---- --- --- -- -------- ---------- ---------- 32, 400 32, 400 32, 400 32, 400
Total area required ____________________________ ------------------- - . 86 1. 47 2. 34 2. 76
Area of flange angles------------------------------------------ -- --- . 69 . 69 . 94 . 94 Net area ______________________________________ -------------------- .17 . 78 I. 40 1. 82
Gage required.------------------------------- ---------- --- ------- --------- .. . 0114 . 0204 . 0266 Actual gage ___________________________________ ----- --- -- ---------- . 0160 . 020 . 020 . 028
R/t. _ ----- ---- --------------------------------- ---------- ---------- 42 33 33 27
Buckling, P/A---- ----------------------------- ---------- -------- -- 23, 000 ---- ------ - 24, 400 31, 000
Total actual area .. ---------------------------- ---------- ---------- ----- ------ ----------- .. ----- -- -- ---------- ---
7
265
24
!?, 635, 000
109, 500
15
56
33,000 a. 32
.94
2. 38
.035
.036
19
33, 000
3.41
Flange angles__________________________________ 2 No. 14 2 No. 13
TWIN-ENGINED OBSERVATION WING
Design of lower flanges, I . F.
Station. ____ • _____________ ________________ _
2 3 4 5 6 7
8
24
3,640,000
151, 800
13
48
37, 600
4. 04
.94
3.10
.045
.050
13. 5
39, 000
4. 36
8
__________________ , ____ ---- ----_____ , ___ , ----1-----1----1
Depth between centroids _________________ inches.. 6 8. 38 10. 59 14. 00 17. 40 20. 75 24. 00
I. F . moment._. __________ _________ incb-pounds.. 7, 950 34, 600 81, 500 207, 000 410, 000 705,000 1, 085, 000
I. F. axial load __________________________ pounds.. 1, 325 4, 130 8, 630 14, 800 23, 600 34, 000 42, 500
FS distance factor, H. !___________________________ . 678 . 684 . 692 . 702 . 720 • 727 . 739
Axial load, FL flange ____________________ pounds.. 898 2, 820 5, 960 10, 380 17, 000 24, 700 31, 400
Axial load, RL flange _________ ______ _______ do____ 427 1, 310 2, 670 4, 420 6, 600 9, 300 11, 100
Allowable stress taken as 25,000 pounds/square inch
Area required, FL __________________ squareinch _ ---------- .11 I .24 .42 .68 .99
Area required, RL. ------------------------do ___ ---------- ---------- .11 . 18 . 254 . 37
Total area, FL ____________________________ do__ __ .114 .114 . 46 • 46 • 690 . 975
Total area, RL __ __________________ ________ do_ ___ .114 .114 .114 .184 • 38 • 38
Section FL flange·----------- - --- --- -- -- ------- --- 1 #7 1 #7 1 #7 \#M 1 #14 { i ~i~ }{
Section RL flange________________________________ 1 #7 l #7 l #7 1 #5 1 #8 1 #8
1.25
.45
1.26
. 49
2 #15 }{
1 #8
1 #6
24.00
1, 4.98,000
63,400
. 739
46, 800
16,600
1. 87
.67
1.886
. 76
2 #15
2 #16
2 #8
18
TWIN-ENGINED OBSERVATION WING
Station.----- ___________ --- _______ _
Design of webs
FRONT WEB
2 3 4 5 6 7 8
1---------------1·--------------- ---------
Distance from station L-------------- -
Depth between centroids _________ ____
Shear, pounds. ________________________
t, required _____ ___________________ - -- - -
Actu~l '---- --- --------------- -- --- - - - -
DDiesptathn cbee ftrwoeme nt icpe.n-tr-o-i-d-s- _-_-_-_-_-__-_-_-_--_-_-_-_
Shear, pounds.- -- ------------ ·- --- ___ _
t, required ____ - - - - -------- -- - - ----- - - --
Actual t. _________ ------------- --- -----
Front web:
0
6. 5
750
----------
. 010
0
4
470
.0047
. 010
35
8. 75
1, 778
.0074
.010
REAR
35
5. 98
1, 136
.0069
• 010
67. 5
10. 83
3, 035
.0102
. 016
WEB
67. 5
7.82
1, 970
.0081
. 010
117. 5
14.05
5, 470
.0141
.016
117. 5
10. 67
3, 655
. 0125
. 016
167. 5
17. 25
8,590
.0181
.026
167. 5
13. 50
5, 970
. 0161
.016
17
Flanged depth=65+265xd d=distance from station 1.
Station. ___ -- -- ----- ____ -------_
Thic I < ness. t= 2S S 55,000d-Z7,500d"
Rear web:
Depth between centroids=4+;
5
d.
s
t-27.500d.
TWIN-ENGINED OBSERVATION WING
Design of vertical stiffeners
FRONT BEAM
2 3 4 5
217. 5
20.45
12, 200
.0216
.026
217. 5
16. 30
8,450
. 0188
. 024
6
265.0
23. 50
16, 320
.0252
.026
265. 0
18. 50
12, 500
. 0245
. 024
7
330.0
23.50
10, 000
. 0155
.016
330. 0
18. 50
16, 490
.0320
. 032
Shear, II. L -----------·------------ 750 1, 778 3,035 5,470 8,590 12, 200 16, 320
Distance from station L ___________ _ 0 35 67. 5 117. 5 167. 5 217. 5 265
Depth, centroids------------------- 6. 50 8. 75 10.83 14. 05 17. 25 20. 45 23.50
Rib spacing ______ ·--- -- ------ ------ 18 18 18 18 18 lS 15
Stiffener ~pacing ________ ____ __ ----- - 9 9 9 9 18 18 15
Load on stiffener ___________________ 1, 140 1,825 2, 510 3, 500 8, 970 10, 740 10,420
Area required. ______ ---- ------- -- -- . 045 .073 . JOO .140 . 360 . 469 . 418
Section (2 per station) _______ ______ ~X~X.025 ~X~X.050 ~X~X. 064 ~X~X. 064 lXlX. 093 lXl X~ 1x14
Total area. --- ------- ----- ------ -- -- .050 .10 .160 .160 . 382 .50
Allowable stress=25,000.
17
Depth=6.5+265Xd.
d=distance from station l.
The vertical stiffeners will be considered as angles with a bncklmg strength of 25,000 pounds per square inch.
It will be necessary to rivet these stiffeners to the webs in order to place the requrred number or rivets.
Station. __________________ ___ Depth between centroids _______ _
Shear ______ ---------- -- ----------
Rib spacing ___ -------- - ----------
Stiffener spacing_ ::-____ -----------
Load on stiffener _________ ____ ___ _
Area required ___ --------- - --- ----
Section (2 per station) ______ _____ _
Total area _______________________ _
Allowable stress=25,000.
TWIN-ENGINED OBSERVATION WING
4
470
18
9
1, 060
.042
~2X~X. 025
.050
Design of vertical stiffeners
REAR BEAM
2
5. 98
1, 136
18
9
1, 710
.069
~X ~X.050
.100
7.82
1, 970
18
9
2,270
. 091
~X~X.050
.100
4
10. 67
3, 655
18
9
3,080
.123
%X%X.064
.160
13. 50
5, 970
18
9
3, 980
.160
:liX;liX.064
.192
6
16. 30
8,450
18
9
4, 670
.187
;liX;liX.064
.192
. 50
18. 50
12, 500
15
15
10, 150
.406
lXl X~
.50
8
11, 980
330
23. 5
13
13
6, 350
.254
ixix.093
.279
8
18. 50
16,490
13
13
11, 580
.463
lXlX~
. 50
19
TWIN-ENGINED OBSERVATION WING
Weight estimate-one-half wing
I
Amount Section
--·-1---1---
Item Unit weight
Webs:
0.032 x 20 ____________________ 0.1011 pound .per cubic inch ____ _
Total
weight
Pound
3. 6
{
.55 inches __________ _
Rear ___________________ _ 110000 iinncchhees; _________ _
120 inches:::::::::::
0.024 x 19 ____________________ 0.1011 pound per cnbic inch ____ _
0.016x13.5 _________________ 0.1011 pound per cubic inch ____ _
4. f,
2. 2
0.010 x 7.5 ___ ________________ 0.1011 pound per cubic inch ____ _ 0.9
11. 3
Front_ ________ __________ 185 inches __ _________ 0.016 x 20 ____________________ 0.1011 pound per cubic inch_____ 6.0
{
100 inches ___________ 0.026 x 22 ____________________ 0.1011 pound per cubic inch_____ 5. 8
llO inches ___________ 0.010 x 10 ___ __ __ ____________ 0.1011 pound per cubic inch_____ 1.1
12- 9
Flange stiffeners:
A=.140 _____ _ 0.1011 pound per cubic inch ____ _
12 at 24 inches _____ _ A=.250 ____ ___ 0.1011 pound per cubic inch __ __ _
6 at 19 inch& ______ _ !8 at 24 inches ______ _
Front web ______________ 10 at 15 inches _____ _
% x % x .093
1x1 x,..
lxlx.093
% x%x .064
~ x ~ x .050
~ x ~ x .024
A=.19L ______ 0.1011 pound per cnhic inch ____ _
A=.080 ______ 0.1011 pound per .cubic inch ____ _
2. 7
7. 3
2. 2
1. 2
0.5
0.2
8 at 12 inches ______ _ A=.050 ______ 0.1011 pound per cubic inch ____ _
8 at 9 inches _______ _ A=.024 _______ 0.1011 pound per cubic inch ____ _
!12 at 19.5 inches _____ 1x1 x l-8
10 at 16 inches_______ H x % x .064
Rear web _________ ______ 4 at 12 inches _______ % x % x .064
12 at 8 inches _______ ~~ x ~ x .050
8 at 5 inches____ ___ __ ~ x ~ x .024
A=.250 ______ 0.1011 ponnd per cubic inch. ___ _
A=.091_ ______ 0.1011 pound per cubic inch ___ _ A=.080 _______ 0.1011 pound per cubic inch ___ _ _
A=.050 ______ 0.1011 pound per cubic inch ___ _ _
A=.024 ______ 0.1011 pound per cubic inch ___ _ _
Upper flange angles; front {420inches __________ No.13 A=.470 _________ __ O.lOllpoundpercubicinch _____ _
and rear. 330 inches ___________ No. 14 A=.345------------- 0.1011 pound per cubic inch ____ _
!320 inches __________ _
ti.5 inches ___________ _
Lower flange angles __________ f50 !nches __________ _
270 mches _________ _ _
205 inches __________ _
• 50 inches ___________ _
No.15
No. 16
No.H
Ne. 7
No. 8
No. 5
A= .630 __ __________ _ 0.1011 pound per cubic inch ____ _
A=.313 _____ ____ ___ _
A=. 345 _______ __ ___ _
0.1011 pound per cubic inch ____ _
0.1 011 pound per cubic inch __ __ _
A=. 114 ___ ________ _ 0.1011 pound per cubic inch ____ _
A=. 380 _________ ___ _ 0.1011 pound per cuhic inch ____ _
A=. 184 ________ __ __ _ 0.1011 pound per cubic inch ____ _
13.1
5.9
1.5
0.4
0.5
0. 1
8.4
20.0
11. 5
31.5
20.4
I. 8
5. 2
3. 1
10. 0
1.0
41. 5
!60 inches ____________ 0. 050 x 58 x I. 23 _____________ 0.1011 pound per cubic inch___ __ 21. 7
50 inches _____ ______ _ 0. 036 x 58 x I. 23 _____________ J.1011 pound per cubic inch_____ 13 O
Corrugated upper flange ___ __ 50 inches _______ _____ 0. 028 x 58 x I. 23------------- O.lOll pound per cubic inch _____ 10.1
110 inches ___ ________ 0. 020 x 58 x I. 23 ______ _______ 0.1011 pound per cubic inch ___ __ 15. 9
95 inches ____ ________ 0. 016 x 58 x 1. 23------ ------- 0.1011 pound per cubic inch___ __ 11. O
71. 7
rose covering ___ ____________ 330 inches ___________ 0. 020 x 48 ___________________ 0.1011 pound per cubic inch_____ 33. 5
Bottom skin _________________ 330 inches ___________ 0. 012 x 100 ___________________ 0.1011 pound per cubic inch_____ 14. 6
Upper corrugated skin _______ 330 inches ___________ 0. 012 x 100 ______ _________ ____ O. lOll x 1. 23___ __________________ 18. O
Ribs ________________________ 23 inches ____________ ------------------------------ 2-pound average_ __ ______________ 46. o
Nose ribs ____________________ 46 inches ____________ ------- -- --------------------- 0. 5-pound average_______________ 23. O
Wing tip ___ _________________ 12,000 squ are inches_ 0. 020 ___ --------------------- 0.1011 pound per cubic inch __ ___ 25. O
Controlrods,cranks,cables,etc ________ __ ___________________ ___________ ---- __ __ ____ _ _ _ _ _ __ __ __ _ __ ___ __ __ _ _ _ _ __ _ ___ 15
Aileron, spar, structure, etc __ ----- ----------------- ----------------------------------------------- - ------ -- - ------ - 10
Miscellaneous fittings ________ ---------------------- --- ----------------------- ____ ---------------------------- - ----- 15
TWIN-ENGINED OBSERVATION WING Area, half wing ____ ___ ________ 289 square feet.
Weight less ribs ______________ 321.5 pounds.
Ribs at 25 per cent of 321.5_____ 80.5 pounds.
Unit weight ____________ _____ 1.39 pounds per
square foot.
1.l X unit weight_ ________ . ____ _ 1.53 pounds per
P ead weight ____ ______ 402. 0 pounds. square foo~.
IV. TRANSPORT WING
Thickness ratio, chord CD = ll.76 + 3
3
3
3
6
(18.46-
11 .76) = 12.42.
Arca of section CD'EF =
69.4t 170
X 303 = 36,300
square inches.
Thickness ratio, chord AB= ll.76-J
3°6
x (6.70) =
TotaL __ ___________ ___ _ 41,690 square inches.
P ounds
10.36
Equivalent chord C'D'=i~:!~ x 103 = 69.4 inches.
Gross weight of airplane __ _____ _______ _____ _ 12, 500
Estimated wing weight____ ____ _____ ___ _____ 1, 500
Equivalent chord A'B'=i~:!~ X 63 =35. 3 inches.
Area of section AB'CD1=
69
.4t
35
·3x 103=5,390
Net weight on wing _______ _______ _________ 11, 000
36,300Wd+ 0.9X 5,390Wd=5,500
36,300Wd+4,850Wd=5,500
Wd=l,337 pounds per
square inches. square inch.
31
-+-----+-l!_r qnt web
63 ~· 170
~-+-----1-- Rea.r ~_e_b ____ _
Of nacelle group ___ _
100
- tertt wt;!f.>-- - - - - so
~ ql.l1:_"~- - -- - .----100---..-
Of airplane
Per rent
chord
Distance
along
chord
---- -
0 0
1)4 2.12
2r.l 4. 25
5 8.50
7~ 12. 75
IO 17.00
20 34.00
30 51.00
40 68.00
50 85.00
60 102. 00
70 119. 00 so 136.00
90 153. 00
100 170. 00
---
]'JGU!tE 11
TRANSPORT WING
Airfoil ordinates
Root I ---1· Chord= 170 inches
Tip
Chord=90 inches
Ordinates !
----
Ordinates
Upper Lower I Upper Lower
Distance
along
---.,--- - -1--------1 chord l---~---1 ---~~--1
Per cent Inches Per cent Inches P er cent Inches Per cent Inches
- -------- --- --------- ------
4. 33 7. 36 4. 33 7.36 I 0 2. 76 2.48 2. 76 2. 48
8.09 13. 75 I. 62 2. 75 1.125 5.15 4.63 1. 03 0. 93
9. 54 16. 21 1.00 l. 70
·1
2. 25 6. ll 5.50 0.63
I
0. 57
11. 81 20.10 0.46 0. 78 4.50 7. 52 6. 75 0.28 0.25
13. 58 23. 05 o. 22 0. 37 6. 75 8. 65 7. 78 o. 14 o. 12 I
14.85 25.25 0.10 0.17 9. 00 9.45 8.50 o. 07 0.06
" M 13.50 10. 56 9.50 -- -------- ----------
17. 73 30. 15 ~~~~===~~~ ~~= :~~~~~~ I
18.00 11. 28 10.15 ---------- ----------
18.46 31. 35 27.00 11. 76 10. 59 ---- ---- --'----------
17. 89 30.40 36.00 11. 42 10.29 ---------- -------- -- 16.21 27.55 ---·------ --- ·---·
--··---·-i---- ---- 13. 83 23.50 ------------- ·---· -- 54. 00 8 81 ;· 83
ll.11 18.90 -------------·---· -- 63. 00 7.08 6. 36 ______.. ,.., __ ----------
7.88 13. 40 ---------- ---·---· -- 72. 00 5. 02 4. 51 ---------- ------·--- 4. 31 7.34 ---·------ --- ·---· -- 81.00 2. 72 2.45 ---------- ---------- 0 43 0 73 ...................... ...... ·---· -- 90.00 0.25 0. 22 ---------- ---·------
21
~ t
--·i9-z --- --- ---- s -- ....... --r-- - ---- - -~
-----31---+------- 63
170
FIGURE 12
TRANSPORT WING
Spar distribution factors
Station ___ ____________ __ __________ -- _____ 1 2 3 4
---------
Distance from station L ________________ _______ 0 50 109 1 Actual chord._-------- --------- --- ---------- __ 90 100 112. 4
Distance LE-CP 31 per cent ___________________ 27. 9 31 34. 90
Distance LE-CP 52 per cent_ ___ ______________ 46. 8 52 58. 50 I
Distance LE-FS. ------- ---- __ ------------ ____ 8 10. 96 14. 45
Distance LE-RS.--------- -------------------- 71 73.96
Distance 31 per cent to RS ______ _____________ __ 43. l 42.96 4727.. 4555 1
Distance 52 per cent to FS ______________ _______ 38. 8 41. (}i 44.1
FS factor, H . I. and I. F ___________ ______ ______ . 684 . 682 . 676
RS factor , L. L---- ------------- --- --- ----- - -- - . 616 . 652 . 700
FS factorX5.5. _ ------- - - - ------------- -------- 3. 76 3. 75 3. 72
R S factorX3.5. - --- ---- - - - -- ------------ ------ - 2.16 2. 28 2. 45 1
TRANSPORT WING
Design of webs
FRONT WEB, H. l.
165
123. 9
38.40
64. 30
17. 75
80. 75
42.35
46. 55
. 672
. 740
3. 69
2. 59
_51_6
221 277
135." I 147
42.00 45.GO
70. 50 76. 50
21.05 24. 38
84. 05 1
87. 38
42. 05 41. 78
49.45 52. 20
. 66 .664
. 785 .829
3. 671 3. 65
2. 75 2. 90
7 8
---
333 389
158. 5 liO
49. JO 52. 7
82. 50 88. 5
27. 68 31
90. 68 94
41. 58 41. 3
54.82 57. 5
. 660 . 656
. 871 . 914
3. 63 3. 61
3. 05 3. 20
Station . ____ ______ _______ __ ____ _ _ _ _ 2_ _ __3_ ___4_ ___5_ ___6 ___ 1_ _ ,_ _8_ _
Distance from station 1 (d) __________ _ 0 50 109 165 221 277 333 389
Depth between centroids _____________ _ 8 JO. 57 13. 61 16. 50 19. 37 22. 25 25. 12 28. 00
Shear, pounds ______________ _________ __ 862 2,175 4,260 6,COO 9,350 12,460 16,000 19,850 t, required __ ___ ________________ __ ____ _ _ .0039 . 0075 .0138 .0145 .0175 .0198 .0232 .0258
Actual'- - -------------- - ---- ---- --- --- . 010 . 010 . 016 . 016 . 020 . 020 . 028 . 028
SCheenatrr,o pido duenpdtsh- _-_-_-_-_-_--_-_-_-__-_-_-_-_-_-_-_--_-__-_-_- -_
t required ___ __ ________ -- - ----- ---------
Actual'- - -------------- - ----- ---- -----
495
4
.0045
. 010
Front web:
REAR WEB, L. I.
1, 350 6. 57 1·
. 0075
. 010
2,800
9. 61
. 0105
. 016
4,630
12. 50
. 0135
. OIG
6, 740
15. 37
. 016
. 020
Depth between centroids= S+ 3~xd=8+0.0515d·
s
t=27,500d
Rear web:
Depth between centroids=4+0.0515d.
t __ s _ _
~7,500d
9,900
18. 25
. 0197
.020
13, 450
21.12
.0250
. 028
17, 600
24. 00
. 0284
. 028
.I
I
I
I
Ii
22
TRANSPORT WING
Design of corrugated upper flange
Station ____ -- - --- __ ________ __ ------ __ 2
D istance from stat10n !_ _______________ ____ 0 50
Depth betveen centroids___ _________ ____ __ 10 12. 31
Bending moment, H. L---- ---- - ---------- 31, 500 143, 000
Axial load----- ------------------ --- - ------ 3, 150 11, 610
Rib spacing_____ ___ ________________ ________ 18 18
L/p cormgations __ ______ __________________ - ----- ---- ---- --- - ----
.Allowable P/A corrugation ________ ___ _____ ----------------- - ----
Total area required ____________________ ____ ------- --- ------- - ___ _
Flange angle area __________ _____ ---- - ----- __ -- ______ , ___________ _
Net area required ____ ________________________________ , ___________ _
t required ____________ __ --------------- -·---- --- - ----- - '------ ------
j[~~~~~~~~~~~~~~~~~=~~~~~~~~~~~~~~~~~ ::::::::::!::~~~~=~:=
1 Decrease due to nacelle weight.
Depth between centroids=l0+:9 d=10+0.463d.
R=0.675 inch.
net area A
t-63Xl.23~77.5
p=0.269 inch.
3
109
15. 05
4.24, 000
28, 200
18
67
32, 4.00
1. 23
. 69
. 51
.005
. 016
4.2
23, 000
4.
165
17. 63
876, 000
49,600
18
67
32, 4.00
2. 16
.94
1. 22
.0158
.016
4.2
23,000
TRANSPORT WING
Design of lower flang es, I. F.
Station_---------- _______________ _________ _ 2 4
221
20.22
1, 540, 000
76, 100
18
67
32,400
2. 65
.94
1. 71
. 022
.024
28
28, 800
5
6
277
22.82
2, 4.60, 000
107, 800
18
67
32, 4.00
3. 61
94
2. 67
. 034.
. 036
19
34., 600
2 No. 13
6
Depth between centroids ___ _____________ _____ __ _ 10
14.,300
1,430
. 684
978
452
~~ 17~1 20.22 22. 2
Bending moment, I. F ___________ ________ _______ _
Axial load, I . F ____ ------------ ---------- --------
FS d istribution factor ___ __ ------ ---- - ------- ___ _
FS axial load ______ ·----- - -----------------------
RS axial load.-----------------------------------
6~;&,~ ~~:~ ~:~gg 1 7~:~ l,l~:ggg
. 682 . 676 . 672 . 668 . 664
3, 4.50 8, 660 15, 200 23, 100 32, 300
1, 610 4, 140 7, 400 11, 500 16, 700
7
333
25. 4.0
3, 660, 000
144, 000
15
56
33, 000
4.. 37
. 94
3. 43
.043
. 048
14
39, 000
7
25.40
1, 668, 000
65, 500
.660
43, 200
22, 300
Allowable stress, 25,000 pounds per square inch
Area required, FS _______ ____ ___________ ______ __ Area required, RS _________ ·--------------·-------
Section FL_ --- - - -- ------ - -------------- ---- - ----
Area, FL _________________ ·------- -- ------------
Section RL _____________________ _______________ _
Area, RL---- ----- - ---- --------------- - ----------
1 Decrease due to nacelle weight.
.04
.02
1 :;tl2
. 14.6
l #6
.31
.14
. OG
1 #12
.146
1 #6
. 31
. 35 . 61 I . 925 I l. 29 I
. 16 . 30 . 46 0. 67
1 #8 1 ~15 1
{ ! ~~g 2 #19 {
.38 .63 .94 1.36
1 ;:s
. 31
l~
.38
1 #19 I{
.68
l j;l3
1. 72
0.90
2 ;!19
l ill
l. 79
1 ;;19 l #16
.99
8
389
28.00
I 4., 408. 000
158, 000
13
4.8
36, 800
4.. 28
. 94
3. 34.
. 013
. 048
14.
39, 000
8
28.00
I 2, 055, 000
73, 300
. 656
4.8, 100
25, 200
1. 93
1. 01
2 #19
2 #18
2. 09
l ~15
1 #18
1.06
TRANSPORT WING
Corrections for nacelle loads
of the nacelle weight, while the front spar shear de­creases
115 per cent of the nacelle weight.
Weight of nacelle group taken as 35 per cent gross
weight.
Weight of nacelle group 0·;5x 12,500 =2, 180pounds.
The effect of the nacelle group, which will be con­sidered
as acting 65 inches from the fuselage fittings,
is to reduce the beam-bending moments in high and
low incidence, and to increase the rear spar shear,
while the front spar shear is decreased. The mass of
the nacelles will be considered as so located as to cause
the rear spar shea,r at the na,celle to increase 15 :per cent
Decrease in moment at wing weight, H. L =2, 180X
65X 5.5= 782,000 inch-pounds.
Moment at root, H. I = 5,190,000-782,000 =4,-
408,000.
Decrease in moment, I. F=2,180 X 65 X 2.5=355,000.
Moment at root, I. F. =2,360,000-355,000 =2,005,"
000.
The front web will be assumed to carry its full shear
in order to approximate landing shears.
Rear web shear due to nacelle, L. l. = 0.15X 2,180X
3.5= 1,150 pounds.
This will act at stations 7 and 8.
Station _______ -- -- - _______ ______ ____ _
Shear __ __ _____ _______ ___________ __ ------_ 862
Depth, centroids_______ ________ __ ___ _____ 8
~J1ir~g:;~gaciii{L~:::::::::::::: : : :::::::: ig
Load on stiffener--- - --- - -- --------- ----- _ 970
23
TRANSPORT WING
Design of web stiffeners
FRONT WEB
2 3
2, 175 4,260
10. 57 13. 61
18 18
9 18
1, 850 5, 625
Area required __ ------------------ --- --- -- -------------- . 074 . 275
Section (2 per station)____________ ________ ~X~X. 050 ~X~X.050 ~X~X.093
Total area_____ __ ______ ___ __ __ ______ ______ .10 .10 .279
REAR WEB
Shear __ ____ -- --- __ - ---- -- -- -- -- -- -- -- -- 495 1,350 2, 800
Depth, centroids . ___ - ----- - ---- -- -- ---- 4 6. 57 9.61
Rib spacing ____ --- --- --- -- ------- -- -- -- 1 18 18 Stiffener spacing. ___ ____ ___ __ ___ ________ 9 9 9
Load on stiffener- --- ---- - --- - ---------- I, 100 I, 850 2,620
Area required_ ___ ___ __ --- - ---- -- ------ -- .045 . 074 . 105
Section (2 per station)_- ---------------- ~X~X .050 ~X~X.050 5 x~X.064
Total area_--- ---- --- --- ------------ -- .10 . 10 .16
Allowable stress, 25,000 pounds per square inch.
4
6,600
16. 50
18
I
7,200
. 288
!XI X. 093
. 372
4, 630
12. 50
18
9
3, 340
.134
5x 5X.064
. 16
5 6 7 8
9,350 12, 460 16, ()()() 19, 850
19. 37 22. 25 25.12 28. 00
18 18 15 13
18 18 15 13
8, 700 JO, JOO 9,560 9, 220
. 348 .404 .372 . 369
IX I X.093 1x 1xA 1x 1x § 1x 1x§
.372 .50 .50 .50
6, 740 9,900 14, 600 18, 750
15. 37 18. 25 21.12 24. ()()
18 18 15 13
18 18 15 13
7,900 9, 760 10,400 10, 150
. 314 . 39 . 415 . 406
!XIX. 093 I 1x1x§ 1XlX1
1X1xk
.372 . 50 . 50 . 50
TRANSPORT WING
Investigation of torque at wing root
t=shear stress at any point where skin thick=t.
Q=torque.
Consider an eccentricity of 0.25 per cent M. A. C.
in the low incidence condition.
M. A. C. = 103 inches
Torque at r oot=0.25X 130X 5,500X3.5=626,000
inch-pounds.
A=mean area of section.
in corrugated sheet
- 626,000
T-1,765 X .048
which is safe.
7,400 pounds per square inch,
Assume that all the torque is to be carried by the box
portion. Solving for the minimum skin thickness on the lower
Area of box section at root= 28X 63 = 1,765 square surface
inches, approximately.
Using the general approximate equation
Q
T=2At
t - 626,000 -o 013 . h ·
-l,765X27,500- . mc '
therefore 0.016 material will present a safe margin.
I
24
TRANSPORT WING
Weight estimate-one-half wing
Item Amount Section Unit weight
Upper flange angles __________ {
Lower flange angles _________ _
Corrugated upper flange _____ {
Rear web--- - --- -- ---- - ------{
Front web __________ ___ ______
Stiffeners:
Rear web ---------------{
Front web---------------{
Lower covering _____________ {
Inches 520 No. 13 A=.47 _____________ _
430 No. 14 A=. 345 ____________ _
475
475
464
184
l12
112
172
160
56
60
110
120
56
56
143
120
112
l12
100
440
120
280
130
488
230
90
220
475 x 1.23
No.19
o. 18
No. 15
o. 16
No. 8
' o. 12
No. 13
No. 5
No. 6
A=. 68--------------1 A:_. 432-------------
A-. 63-------------- A=. 313 ____________ _
A= .38 ___ __________ _
A=.146-------------
~:: ik::::::::::::I
A=. 098-------------
77. 5 x. 048.------------------
77. 5 x . 036_ - ----------------
77. 5 x. 024. -----------------
77. 5 x. 016. ---------------- -
2128 xx.. Q02208 __ _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-__-_-_-_-
137 xx .. 00\106 _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
14. 7 ( !+ 28) =
2 4 24
1x1 x 'r8 A=. 25 ________
1x1 x .093 A=.186 ___ ____
~~ x % x .064 A=. QS ________
;~x)6x.05 A=. 05 ____ ____
1x1 x ;~ A=. 25 __ ______
1x1 x .093 A=. 186 _______
'}4 x% x .093 A=.14 _______
l6 x l1! x .050 A=. 05 ________
70 x .016 ______________ _______
50 x .024 _____________________
70x .12 ____ __________________
Pounds per
cubic inch
0.1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
.1011
. 1011
.1011
.1011
.1011
. 1011
.1011
.1011
.1011
. 1011
.1011
• JOH
. 1011
. 1011
.1011
.1011
. lOll
. lOll
.1011
Total
weight
Pounds
25. 0
14.8
39. 8
31.5 I 8.0
7.1
3. 5
6.6
2. 2
2.6
1.1
I. 1
63. 7
44.0
15. 6
10.5
18.0
88.1
7. 5
4.1
2.4 o. 7
14. 7
23. 2
ll. 2
2. 2
2. 2
0. 8
16. 4
12.4
4. 3
1.3
1.1
19. 1
53. 5
57. 0
51. 0
161. 5
Wing tip, (partially included in skin estimates)----------------------------- - --------- -- 10
Control rods, cables, etc __ ----- ___________________________ ---- ____ ----- - _________ -- _ _ 20
MAiilsecreolnl,a nspeoaur,s sftirtuticntgusr e__, _e_t_c_ _____ -_-_-_-__-_-_-_-_-_-_-_-_-_-_-_-_-_--_-_-_-_-_-_-_-_-_-_-_-_-_-__--_-__-_-_-_-_-_-_-_-_-_-_-_- -------------_-_-__- 1250
Total weight less ribs_ ________________________________________________ ____ ____ ---------
Ribs at 25 per cent of 485.5 pounds------------------------- ----------------------------
Area, half wing, 427 square inches.
Unit weight, 1.42 pounds per square inch.
1.1 X 1.42, 1.56 pounds per square inch.
55
485. 5
121. 5
607.0
TRANSPORT WING
Shears and moments
Station-------------------------------------- o __________2_ _1 ==1__ _______ ==--5_ _ j-_-_-_--_-_--_, ___6_ _, ____ ,_ ____, _ __ __8_ _
1
Distance from station 2---------------------------- ------- ------- -------- ------- --------- -------- 59 -- ----- - 11.1 171 --- ----- 227 283 339
Chord, equivalent wing____________________ _______ 35. 3 ------- 52. 4 ------- 69. 4 ------ -- 86. 9 - ------- 103. 5 120 ---- ---- 136. 7 153. 3 -------- 170
Distance between station, x _______________________ ------- 50 -------- 50 --------- 59 --------- 56 --------- 56 ---- ------- 56 ·---------- 56 ---------- - 56 ------------
Running load, pounds pet· inch ____________________ 1 3. 78 ------- 1 6. 30 ------- 9. 26 -------- 11. 60 -------- 13. 80 -------- 16. 02 -------- 18. 22 -------- 20. 50 -------- 22. 70
~~anb~t~~~;~r:&i:.'ivx:::::::::::::::::::::::: ::::::: 52g~ :::::::: 13;~ ::::::::: 105~~ ::::::::: 12;J~ ::::::::: i47~5 ::::::::::: 11. 12 ___________ 19.36 ___________ 210~0 1 ''l
Shear=:!:lVX------------- -------------- - ---------- ------- ------- 229 ------- 582 -------- 1, 1<12 ------ -- 1, 787 -------- 2, fi47 ----~'.~- -----3;4ff ----~~~- -----4;403- --~~--:- -----5,-500--
Moment iv;'--------------------- --- ----- -- ------------- 5, 730 -------- , 830 --------- 16, 500 --------- 18, 050 -- ------ - 21, 250 ----------- 24, 350 ----------- 27, 600 -----------I 30, 750 ---------- --
Moment SX-------------------------------------- - ------- ------- -------- ___ ,___ 11, 440 34, 900 --------1 64, 100 100, 000 142, 700 191, 000 247, 000
Total moment_ ____________________________________ -------------- 5, 730 26, 000 77, 050 -------- 159, 200 280, 450 447, 500 666, 100 943, 850
H. I. moment__------------ ------------------- ---------- - --- ---- 31, 500
I. F. moment--------------------- - ----------------------- - ------ 14, 300
l'S distance factor·------- ------------------- ------- ------ -- ----- 3. 76
FS shear _________ ___________ _______ -------------- _______ -- ---- - 862
RS distance factor_ __ ______________________________ ------- __ · ----
RS shear_ ----------------------------------------- ___ __________ _
1 0.8 tip loading.
' Factor or 0.007 used to bring shear to 5,500 pounrls.
2. 16
495
143, 000
62, 500
3. 74
2, 175
2. 28
1,350 ----------------1
424, 000
193, 000
3. 72
4, 260
2. 45
2,800
0
876, 000
398, 000
3. 69
6, 600
2. 59
4, 630
l, 540, 000 2, 460, 000 3, 660, 000 5, 190, 000
700, 000 1, 120, 000 1, 668, 000 2, 360, 000
3. 07 3. 65 3. 63 3. 61
9, 350 12, 460 16, 000 19, 850
2. 75 2. 90 R. 05 3. 20
6, 740 9, 000 13, 450 17, 600
/