Structures PDR 1

Team Boiler Xpress

Oneeb Bhutta Matthew Basiletti

Ryan BeechMicheal VanMeter

October 12, 2000

Topics of Discussion

Aircraft Weight Wing Weight EstimationStructural Material Properties Wing, fuselage, podsWing layout SparsLoad Analysis Theoretical Model Maximum Bending Moment and

Deflections and Diagrams Test of Actual Wing

Topics of Discussion

Weight Estimation Center of Gravity Parts LocationLanding gear system

component Number Weight ea (oz) total component (oz) wt fractionrecvr (ea) 1 1.5 1.50 1.1servo (ea) 4 1 4.00 2.9data logger (ea) 1 16 16.00 11.4gyro and controller (ea) 1 3 3.00 2.1motor cells (1.4ah nicad) 10 1.3 13.00 9.3wire for motor (inches) 70 0.0317 2.22 1.6motor and gear box (ea) 1 11 11.00 7.8propeller (ea) 1 2 2.00 1.4speed controller (ea) 1 1.2 1.20 0.9wing (sq ft) 13.5 2.3 31.05 22.2pod (ea) 2 5 10.00 7.1Main fuselage (ea) 1 12 12.00 8.6landing gear/wheels (ea) 3 1.5 4.50 3.2horizontal tail (sq ft) 2.5 4.37904 10.95 7.8Vertical Tail (sq ft) 1.4 4.37904 6.13 4.4Boom (ft) 6 0.6 3.60 2.6Miscellaneous (oz) 1 8 8.00 5.7

Total Weight (lb) 8.76 lbwing loading 0.65 lb/sq ft

CLmax 1.53 Stall speed 19.16 ft/s

Airframe Weight 4.66 lb

Aspect Ratio 9 Chord -root (in) 17.20taper Ratio (tips) 0.6 -tip (in) 10.32

Span (ft) 11.02

Weight Build up

Aircraft Weight

Material lb/unit Amt reqd weight (oz)foam (per in^3) 0.013 1470 19.351/4x1/8 balsa (per in) 0.003 480 1.53micafilm (per sq.in) 0.001 3360 2.74

add for misc structure 6.00

Foam wingTotal wing Weight 29.61

Density (lb/sq ft) 2.28

Wing Weight Estimation

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 (Actual Test Result; Whiskey Tango Team, Spring 1999)

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

Wing Spar Box Structure

Rear spar for control surface hinges

Styrene wing core

Balsa spars carry bending load 0.375 in x 0.25 in

L.E. Reinforcement

Assumptions:

•Box beam (ease of analysis)

•Moment of Inertia (Stringers)

•Spars carry loads & positioned at max camber

Analysis of Loads

Model as cosine lift distribution

•Structural weights distributed along span•Method of Analysis (Theoretical Model)

)*cos(')( 22 b

xLxL dxLxCosLLbeam

L

)2

('0

Bending Moments

Maximum Moment = 25.86 lb/ft

Safety Factor = 2.5g * 1.5

Wing Deflection

Max Deflection = 1.93 inches

Stress in the Wing

Sigmamax = 1241 psiSigmacritical = 1725 psi

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

IyMmax

max

Sand Bags

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