Ashley Brawner Neelam Datta Xing Huang Jesse Jones Structures 2 PDR Team 2: Balsa to the Wall Ashley Brawner Neelam Datta Xing Huang Jesse Jones Matt Negilski Mike Palumbo Chris Selby Tara Trafton

Overview Weight determination Fuselage and tail Analysis of wing loads Wing structure

CATIA Model

CATIA Model Component locations based on previous CG calculations Will provide more accurate CG value Will lead to accurate moments and products of inertia

V-n Diagram Design Point: Vertical turn radius = 28 ft Velocity = 60 ft/s Load factor = 5

V-n Diagram Maximum Design Load Factor = 7.5

Simplifying Assumptions Modeled lift with elliptic distribution Approximated airfoil as ellipse for analysis

Discretized Wing

Bending Load

Bending Load t = 0.00025 in t = skin thickness y = vertical distance from neutral axis M = bending moment I = moment of inertia

Twisting Analysis T = Torque Cm = Moment Coefficient c = Chord length q = shear flow A_bar = Airfoil cross-sectional area theta = twist angle/unit length

Twisting Analysis

Wing Skin Material E-glass/Epoxy Known Values weight [oz] thickness [in] 3 0.0046 4 0.0059 6 0.0093 7.5 0.0107 http://www.shopmaninc.com/cloth.html

Wing Skin Material Available Materials weight [oz] thickness [in] cost per square yard 0.5 0.00075 $6.50 0.58 0.00087 $6.00 0.73 0.001095 1.4 0.0021 $4.25 2 0.003 $4.50 2.3 0.00345 $5.00 http://www.deltronix.net/cgi/acp_display.exe

Fiberglass Weight [lbf] Wing Skin Material Wing Area [in^2] 1465.078 Wing Area [yd^2] 1.130 Fiberglass Weight [lbf] 0.035 Epoxy Weight [lbf] 0.071   Wing Volume [in^3] 478.516 Wing Volume [ft^3] 0.277 Foam Weight [lbf] 0.485 Wing Weight [lbf] 0.591 With 0.5 oz E-glass/Epoxy

Wing Skin Material http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/finishing_techniques/apply_fiberglass_finish/index.htm

Summary Lots of work still to be done… Wing skin will be 0.5 oz E-glass/Epoxy Current weight is approximately 0.6 lbf Questions?

Questions?

Material Properties Material Properties Table E-Glass Fiber S-Glass   E-Glass Fiber S-Glass E-glass (Fabric) Balsa Wood Carbon Polyurethane Foam Density (lbs/in^3) 0.071 0.072 0.068 0.054 0.065 0.0046 Tensile Strength (ksi) 165 250 62.8 0.16 325 Shear Strength (ksi) 12.9 10 12.2 0.54 10.6 0.2 Longitudinal Young's Modulus (10^6 psi) 6 6.5 3.55 0.0094 21.3 0.0051 Transverse Young's Modulus (10^6 psi) 1.5 1.6 3.45 Shear Modulus (10^6 psi) 0.62 0.66 0.68 0.0085 1 0.00145 Poisson's Ratio 0.28 0.29 0.11 0.4 0.27 0.25

Load Factor – Max Lift Fix FontSize in Labels

Load Factor – Level Turn Fix FontSize in Labels

Load Factor – Vertical Turn Fix FontSize in Labels

Wing Centroid

Load Analysis

CG Approximation

CG Approximation BALSA Component weight (lb) x pos (in.) y pos (in.) Structure 2.26 15.04 0.81 Speed Controller 0.26 6.00 1.34 Batteries 1.25 2.00 Motor 0.59 5.00 Payload 1.00 3.00 -0.50 Gyro 0.01 3.50 1.75 Tail Servos 0.08 7.50 0.54 Receiver 0.04 Total Weight 5.50   CG 8.15 0.77 Aerodynamic Center 9.26