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December 1, 2003PDR3 Walk-around Tractor Engine Data Boom Simple Fuselage Design Robust Wing Detachable Pod
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December 1, 2003 PDR 1
Team 5 Structures and Weights PDR #2Team 5 Structures and Weights PDR #2
• Scott Bird• Mike Downes• Kelby Haase• Grant Hile• Cyrus Sigari• Sarah Umberger• Jen Watson
December 1, 2003 PDR 2
PreviewPreview
• Tail Beam Sizing • Pod Support • Wing And Landing Gear
Attachment
• Fuselage Layout
• Parts List and Weight
December 1, 2003 PDR 3
Walk-aroundWalk-around
Tractor Engine
Data Boom
Simple Fuselage Design
Robust Wing
Detachable Pod
December 1, 2003 PDR 4
Boom SizingBoom Sizing• Tail boom sizing requirements:
– support the maximum loading conditions• Maximum elevator and rudder deflections
– Small angle of twist– Small deflection
• Assumptions and Chooses– 5g (5 times gravity) is maximum lift loading– Boom support is fixed to fuselage– Spruce
LelLrdrLel
Lrdr
December 1, 2003 PDR 5
Maximum LoadingMaximum Loading
• Maximum Lift of Rudder and Elevator– Maximum Velocity– Maximum Coefficient of Lift
• Maximum deflection
• Maximum Bending Moment– Longest Moment arm
• Max bending at fixed end
lSCVLift 2
21
x
Lift
xLiftMoment *
December 1, 2003 PDR 6
Tail Boom Property RequirementsTail Boom Property Requirements
• Requirement:
– My = maximum bending moment– z=distance from centroid to farthest edge– σxx = ultimate yielding stress (material property)– Iy= Moment of Inertia of cross section
• Requirement: θ small degree at tip in Appendix• Requirement: is small
– E=Young’s Modulus (material property)– I=depends on cross section
z
z
y
y
IyM
IzM
EIPLy3
3
max
L
P
December 1, 2003 PDR 7
Stress CriteriaStress Criteria
December 1, 2003 PDR 8
Twist CriteriaTwist Criteria
December 1, 2003 PDR 9
Tip DeflectionTip Deflection
December 1, 2003 PDR 10
Tail Boom Cross Section PropertiesTail Boom Cross Section Properties
• Compare Cross-Sections to Minimize Weight– Two Rectangles– Box Beam– Circular
c
h
t
x
y
c
h d
t
Two Rectangles Box Beam Circular
Wall thickness (in) ½ ¼ ¾
Height(in) 4 3.5 4Distance Between(in)
2.5 2.5 N/A
Weight (lbf) .69 .67 1.33
December 1, 2003 PDR 11
Pod SupportPod Support
• Considerations– Light Weight– Support Payload– Easily Removable
• Two Supports• Aluminum Rods
– Removable– Spacers
• Brackets to hold Pod in place
• Results=2.2lbs each– Too heavy?
hf
Spacer
December 1, 2003 PDR 12
Wing AttachmentWing Attachment
• Desirables– Easy to remove– Support the wing
• Elastic Bands– Easy to apply and remove
• Spruce Rods
• Solid Skin between Attachments
Wing Attachments
December 1, 2003 PDR 13
Landing Gear AttachmentLanding Gear Attachment
• Failure without disaster– Vertical
• Buckle resistant– Horizontal
• Fail before vertical in joint
• Desired result– If Horizontal at fails joints
first not much structural damage
VerticalVertical
Horizontal
December 1, 2003 PDR 14
Fuselage LayoutFuselage Layout
• Considerations– Support all components
• Engine• Electronics• Pod• Wing• Landing Gear• Tail
– Simple• Easy to build
– Aerodynamic• Smooth transitions• Foam • Composite Skins• Ribs for shape
December 1, 2003 PDR 15
Part’s ListPart’s List
• Yellow- Estimated• Blue -Program Estimated
• Fuselage Weight not complete
Item Weight (lbf)Prop 0.25
Engine 2.04
Fuel Tank 1.00
Reciever 0.11Battery 0.21Wing 7.45
Aft fuselage boom 6.25
Pod 20.00
Servo S3001 0.10
S3104 0.21
S3104 0.21
Tail 4.13
Fuselage 6.80
Landing gear 2.50
Total weight 51.26
December 1, 2003 PDR 16
Finishing Touches….Finishing Touches….
• Analysis booms support of fuselage• Pod brackets, Spacers, and Bolts• Add Solid Skin to Wing• Ailerons Attachment• Engine and other Support• Finalize Weight• Update when other values changes
December 1, 2003 PDR 17
Questions?Questions?
•Questions??
December 1, 2003 PDR 18
Material PropertiesMaterial Properties
Property Aluminum Balsa Spruce Pine
Max bending stress (lb/in^2)
47e3 2.2e3 5656 6.9e3
Shear Modulus (lb/in^2)
4e6 3.13e4 1.73e5 9.38e4
Young’s Modulus (lb/in^2)
10e6 .5e6 1.6e6 1.5e6
Density (lb/in^3)
.0995 .0065 .0145 .0185
”Selection and use of Engineering Materials”, J.A. Charles
December 1, 2003 PDR 19
Wing Box Properties (Rotation Requirements)Wing Box Properties (Rotation Requirements)• Requirement: θ<1 degree at tip
– T=Lift*(distance to shear center)– L=Half span– dis=distance between spars
))(sec)tanh(1( 2221
20
20 LhLLLLBbTA
20
02
bAB
EIEIA f 20
111
)ht.052+
ht.63-(11/3bt=J
5
r
r
r
r3rr
GJGJB rf 0
3ff2
5ff3
f1
421
t1/3h=J
)bt.052+
bt.63-(11/3bt=J
t2+J+2J
ffJ
)ht.052+
ht.63-(11/3bt=J
5
r
r
r
r3rr
tr
b
hr
tf
hf