AME 441: Conceptual Design Presentation B-19 Group 5: Andrea Doyle, Tim Kacmar, Ryan Kirker, Meghan Perry-Eaton, Denis Sullivan, Mike Trela, Thomas Zieg February 5, 2004

Overview Introduction Main Wing Selection Engine Selection Takeoff and Landing Distances Passive Lift Enhancement Static Stability Conclusions

Introduction Design Drivers Allowable Parameters Maximum Level Speed at Constant Altitude Maximum Climb Rate Allowable Parameters Total Planform Area between 400 and 800 in2 Power Plant Consisting of an Electric Motor Internal Cargo Bay of Specified Dimensions Sport Propeller of Specific Pitch and Diameter Digital Radio Control System (7 Channels)

Why a Flying Wing? Advantages Minimum Drag High Speed Absence of Horizontal Tail Maximizes Climb Rate Given AC and CG locations Maximizing Excess Power

Weight Breakdown

Wing Loading Design Drivers: Max Level Cruise  High Wing Loading Max Rate of Climb  Low Wing Loading Large aircraft are not a good comparison. R/C Model Aircraft Wing Loading Professional Kit Models: 12 oz/ft2. Conceptual Design: 27 oz/ft2. Maximize Available Power, Decrease Drag

Overall Wing Design Taper Ratio, 0.4 – Like Elliptical Planform Wing Sweep, 20% – Historical Data Winglets – Decrease Drag, Stability Dihedral, none Winglets & Wing Sweep are effective Dihedral Twist takes away from effective Dihedral

Wing Airfoil Section: EH 3.0/12.0 Low Moment about A.C. -0.002 Thick Section Structure Stability Designed for Flying Wing model Aircrafts

Wing Specifics Flaps for increase lift at take off and acceleration to cruise. Dimensions Wing Area, 600 sq. in. Compromise between low drag and low CL. Wing Span, 5.4 ft A = 7.1, 8.1 with winglets Root Chord, 1.09 ft & Tip Chord .44 ft CL @ cruise, .225

Estimated Cruise Velocity Importance Velocity estimation greatly effects the design of the wing.

Estimated Velocity Theoretical Estimate: 100 ft/s Based on a propeller efficiency ranging from .4 to .6 Conservative Estimate: 80 ft/s Battery will not be fully charged and other losses will occur.

Wing Twist & Angle of Attack Twist: For Stability & Control of Aircraft Minimize Moment @ A.C. Low Stability Factor, 8% Longer Wing Span Good Weight Estimate Calculated -4° of Twist from Root to Chord Root Chord, α = 4 ° Tip Chord, α = 0 ° Mean Aerodynamic Chord, α = 2.5° .817 ft long at 1 ft from the root chord.

Propulsion System Astro 15 Motor 12” X 8” Pitch Propeller 9.78 lbs. Static Thrust 2.16 lbs. Cruise Thrust (2 lbs. of Drag at Cruise)

Take-Off and Landing Analysis CDO= 0.015 Aspect Ratio=7.15 CLG=1 Take-off Weight= 8lb =0.1, wet grass 5 foot obstacle Wing Loading= 1.687 lb/ft2 VTD= 43.34 ft/sec Landing Weight= 7lb Dropped landing gears =0.3, wet grass, large surface area interaction with ground

Lift Enhancement Airfoil Data EH3.0-12.0 Cl max = 1.0 αs 2-D no flaps = 10 degrees CLmax no flaps = 0.90 αs 3-D no flaps = 13.129 degrees Flap Information Plane δf = 30 degrees Sf/Sw = 0.20 cf/cw = 0.25 3-D with flaps ΔCLmax = 0.0189 CLmax = 0.9189 αs 3-D flapped = 11.629 degrees ΔCD0 = 0.0156

Stability

Conclusions Flying Wing Configuration Wing Dimensions Estimated 8 lb Takeoff Weight Wing Dimensions Area: 597 in2 Span: 4.7 ft Root Chord: 1.08 in Tip Chord: .44 in Wing Twist: 5° EH 3.0-12.0 Airfoil Cl max-1.0 3% Camber 12 % Thickness Wing Loading 27 oz/ft2

Power Plant Takeoff and Landing Flap Information Cruise Speed Astro Cobalt 15 Electric Motor -Shaft Output Power: 268 W -12 Cell Pack -2.38:1 Gear Ratio -12x8 Propeller Takeoff and Landing Takeoff Speed: 48.34 ft/s Takeoff Distance: 248.57 ft Landing Distance: 743.12 ft Flap Information Plane Δf = 30 degrees Sf/Sw = 0.20 cf/cw = 0.25 Cruise Speed 80 ft/s

Questions??