Dane Batema Benoit Blier
Drew Capps Patricia Roman
Kyle Ryan Audrey Serra
John Tapee Carlos Vergara
Team 1:
Structures 1 QDRTeam “Canard”
September 28th, 2006
AAE 451 Team 1 2
Wing Sizing• Aerodynamics gives the geometry
• Load case: Resist to 10g (640ft radius at 100mph)
• Materials
0.4 ft
0.3
0.89ft9.3 deg
Swing = 4.16 ft2
MH 43
Thickness:8.5%
With a weight of 5 lb Wing should support 50 lb
balsa
Expanded polystyrene
Easy to built
Good surface
AAE 451 Team 1 3
Sizing Method
• Discretization of the wing
• Determination of the loads
1 3 42
Quarter chord
MAC: application of the lift
For each part, we can figure out:
•The bending moment due to the lift
•The torsion torque due to the aerodynamic moment
AAE 451 Team 1 4
Distribution of Liftoutline and discretization of the wing
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
x axis (ft)
y ax
is (
ft)
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
Lif
t (l
bf)
outline
lif t
The lift is assumed to be linear:
Lift = Wloading x Surface
AAE 451 Team 1 5
Bending Momentbending moment relative to the x position on the wing
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
-0.30 0.20 0.70 1.20 1.70 2.20 2.70 3.20
distance from the root (ft)
ben
din
g m
om
en
t (l
bf.
ft)
bending moment
L1 L2
d1d2
M=L1.d1 + L2.d2 + …..MAC
AAE 451 Team 1 6
Minimal thickness• Assumptions:
– Only bending loading– Foam doesn’t carry the load
• The balsa should resist the load
• We assume the shape of the airfoil is an ellipse
maxb
compG
My cste
I
t is figured out from IG
a
b2
2
ratiochord tb
chorda
( , , )
( , , )GI f a b t
J g a b t
polar inertia
psifailurestressncompressiocomp 5.72
AAE 451 Team 1 7
Skin Thickness
Thicknesses
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
1.40E-01
1.60E-01
1.80E-01
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
root distance (ft)
skin
th
ickn
ess
(in
)
discretizedthicknesseslinearized thickness
constant thickness
Easy to built, but 70% heavier than discretized thickness
Optimal thickness distribution
1.53 in
AAE 451 Team 1 8
Twist and Deflection• Twist
– Assumption: Only the aerodynamic twist (twist due to the swept angle is neglected)
• Deflection
2max _ max
maxmax
1max
2 mT SV C
T L
GJ
_ max
max
0.0318
150 /
23060
m
balsa
C
V ft s
G psi
Lift at MAC
y y’3lift
G
F Ly
EI
y’ with Thales theorempsiEbalsa 6.185
=100 mph
AAE 451 Team 1 9
Twist
twist angle
-1.6E-02
-1.4E-02
-1.2E-02
-1.0E-02
-8.0E-03
-6.0E-03
-4.0E-03
-2.0E-03
0.0E+00
0.00 0.50 1.00 1.50 2.00 2.50
distance from the root (ft)
twis
t ang
le (r
ad)
twist angle
max. twist: 0.7°
AAE 451 Team 1 10
Deflection
deflection
0
0.05
0.1
0.15
0.2
0.25
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
distance from the root (ft)
def
lect
ion
(in
)
deflection
0.21 in
AAE 451 Team 1 11
Carbon Spar Advantages
The minimum skin thickness is too thick to bend around the airfoil shape (from experience)
Method: Assume iso-rigidity for the carbon tube and the skin
(EI)skin=(EI)spar
50% of the load in the spar50% of the load in the skin
Redo the calculations for the skin with 50% of load
AAE 451 Team 1 12
Skin Thickness With Spar
Thicknesses
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
1.40E-01
1.60E-01
1.80E-01
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
root distance (ft)
skin
th
ickn
ess
(in
) with sparwithout sparconstant thickness
From this point, the structure resist without spar
Cut spar at 1.50ft
AAE 451 Team 1 13
Skin Thickness
4.8 in
Balsa sheet thickness
t = 0.06 in ($22 for 253”x36”x1/16”)
ID ≈ 0.32 in
OD ≈ 0.45 in
Thickness ≈ 0.13 in
Final size will depend on market
availability
AAE 451 Team 1 14
CG Location: 33% of Mean Aerodynamic Chord
Mean Aero. Chord (MAC)
CG Estimation/Spar Location
Spar Length = 3.0 ft
(≈1/2 of wingspan)
AAE 451 Team 1 15
Tip Over Analysis
-(Waircraft-Wwing) + FLG – Wwing – Ftip = 0
∑MLG = 0 = -(Waircraft)d1 + (FLG)d3 – (Ftip)d2
Ftip ≈ 0.5 lb
FLanding Gear
Ftip
Wwing
Waircraft-Wwing
y
z
d1 d3
d2
AAE 451 Team 1 16
Landing Gear Calcs
MLG min Spread 12°
MLG dist from CG 5.5 in
Fuselage Height 5.4 in
Propeller Radius 5.04 in
Prop Clearance 5.04 in
MLG fwd Angle 20°
RLG Angle 5°
Rolling AOA 12°
CG to Wing TE 0.43 ft
Racer wheels
carbon or aluminum strut depending on cost
AAE 451 Team 1 17
Questions
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