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The Black Pearl. AME 441: Senior Design Group 1 R yan C obb J acob C onger C hristopher C ottingham T ravis D ouville J osh J ohnson A dam L overro T ony M aloney. Design Proposal. Design Drivers Maximum Level Speed Maximum Climb Rate Objectives Increase Available Power
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The Black Pearl AME 441: Senior Design Group 1 Ryan Cobb Jacob Conger Christopher Cottingham Travis Douville Josh Johnson Adam Loverro Tony Maloney
Design Proposal • Design Drivers • Maximum Level Speed • Maximum Climb Rate • Objectives • Increase Available Power • Decrease Drag • Decrease Weight • Low-Drag Flying Wing • With Drag-reducing winglets
Stability Wing Sweep Wing Twist Reflexed Camber Line Airfoils Proper Payload Arrangement Winglets Fabrication No fuselage or tail Fewer control surfaces Takeoff & Landing Takeoff Sled Landing Skids Payload Arrangement Increased Root Thickness Internal Storage ~ 70 in3 interior Initial Design Considerations
Fuselage Design • No Actual Fuselage • Wing root thickened to accommodate payload • Optimized airfoil fuselage shape
Stability Design • Payload arrangement • C.G. Forward of A.C. Positive Static Margin (SM = 0.11) • Wing Sweep: 20o • Aerodynamic Twist • Reflexed Camber Line Airfoil • Low (or positive) moment coefficient
Stability Design • Winglets • Enhance directional stability • Wing alone is directionally stable • Reflexed trim position
Control Surfaces • Preliminary: • Sf/Sw = 0.2958 • Sa/Sw = 0.1225 • Plane Flaps • CL= 1.5 with flaps • CL= 1.0 without flaps • Final: • Flaps Unnecessary • Flaps & Ailerons Linked • Elevons enhance control authority
Engine Performance • Astro 15 Static Thrust • Predicted Thrust: 6.0 lbf • Actual Thrust: 3.15 lbf • T/W Ratio • Predicted: 0.96 • Actual: 0.75 • 12 x 6 Pusher Propeller • 12 Cell Battery http://www.flyhobbies.com/astroflightcobalt15geared.htm
Battery Complications • 12 Ni-Cad Cells spliced to custom fit forward in bubble • Learning Curve • Discharging, charging problems • Soldering Connections
Takeoff Sled • Steerable sled for 211 ft. takeoff roll • Carbon-reinforced Ply Base • Dowels through wing
Sled Complications • Field bumps/wind gusts change effective angle of attack on each half-span. • Asymmetric lift-off causes binding in dowel slots. • Mechanical forces magnify friction on dowels. • Solution: Hand Launch
Structure • Two main basswood spars • Carbon fiber carry-through spar • Root section 3.25” x 14” cutout for propeller • Thin Balsa wood skin
Landing Skids • Two plastic skids arranged symmetrically • Protected propeller • Absorbed landing impact Motivation for Design Propellers courtesy of H2