Rear spar for control surface hingesStyrene foam wing core

Balsa spars carry bending load 0.25 in x 0.25 in

T.E. Reinforcement

Materials Employed:

•Balsa: Light weight & Strong; Horizontal-Tail•Styrene Foam: Easily Workable;True airfoil shape•Composites: Fiber Glass Pods and hollow Carbon Fiber Booms•Assumptions: Load Carrying ability.

Structures

Mathematical Model

Assumptions:•Wing and Weight loading•Method of Analysis (Theoretical Model)•Safety Factor = 2.5g x 1.5

Wing

P

Boom

Horizontal Tail

Bending Moments

Max Moment = 41.71 lbf/ft

Stress in the Wing

Sigmamax = 2003 psi

Sigmacritical = 1725 psi (Actual Test Result; Whiskey Tango Team, Spring 1999)

Reasons: Light Weight Structure (not Bulky) Safety Factor (worst case scenario) Wing Test Results

I

yMmaxmax

1.5ft

P

Horizontal Tail & Boom Horizontal Tail:Max Stress = 850psiSpar Sizes = 1/8 in x 1/16in

Booms:Max deflection = 0.24 inSF = 2.5g’s x 1.5 Assuming Young Modulus (E)

for aCarbon Epoxy matrix.Testing needed to verify result.

Moment Equations

2''

2'

22

LWLLxWL

xWLM o

oo

)( axPM

xLPM

Wing:

Horizontal Tail:

Boom:

12

.22

2''2' LWLLxWLxWLM ooo

Deflection Equations

4

.6

.24

)(22'3'4' xLWLxWLxWL

xEIv ooo

Lxafor

axPaxEIv

axforaxPx

xEIv

..6

3)(

0.6

3)(

2

2

6

)3()(

2 xLPxxEIv

241224

)(22'3'4' xLWLLxWLxWL

xEIv ooo

Wing:

Horizontal Tail:

Boom:

Deflection of Wing

Moment & Deflection of Horizontal Tail

Moment & Deflection of Horizontal Tail

Moment & Deflection of Boom

Moment & Deflection of Boom

Structural Materials: Wing

Balsa•Light weight/very strong in compression and tension with the grain•Density = 11lb/ft3

•E= 625 ksi•Yield Stress = 1725 psi

Styrene Foam•Easily worked with hotwire or cutting tools•Gives true airfoil shape •Works well in compression when load is well distributed-serves as shear member•Not strong enough for bending loads•Density = 1.42 lb/ft3

Fiberglass

•Good for complex shapes

•Strong

•Skills needed

•3 layers of 1.5 oz cloth with resin = 9 oz/sq. yd.

Carbon Fiber

•Booms

•Light weight & Strong

Structural Materials:

Fuselage and Pods

Geometry and Configuration

Wing:•Sref = 13.5 sq.ft.•Span = 11 ft.•Aspect Ratio = 9•Taper Ratio = 0.6 tip section•Airfoil: S1220

Horizontal Stabilizer:•Area = 2.1 sq ft.•Span = 3.0 ft.

Vertical Stabilizer:•Total Area: 2.0 sq.ft.

11.1’

5.8’

Boiler Xpress