Structures PDR 1 Team Boiler Xpress Oneeb Bhutta Matthew Basiletti Ryan Beech Micheal VanMeter October 12, 2000
Topics of Discussion Aircraft Weight Wing Weight Estimation Structural Material Properties Wing, fuselage, pods Wing layout Spars Load Analysis Theoretical Model Maximum Bending Moment and Deflections and Diagrams Test of Actual Wing
Topics of Discussion Weight Estimation Center of Gravity Parts Location Landing gear system
Aircraft Weight
Wing Weight Estimation
Structural Materials: Wing Balsa Light weight/very strong in compression and tension with the grain Density = 11lb/ft 3 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/ft 3
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 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)
Bending Moments Maximum Moment = lb/ft Safety Factor = 2.5g * 1.5
Wing Deflection Max Deflection = 1.93 inches
Stress in the Wing Sigma max = 1241 psi Sigma critical = 1725 psi Reasons: Light Weight Structure (not Bulky) Safety Factor (worst case scenario) Wing Test 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