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