Critical Design Review

1. Purdue University AAE 451 Fall 2006 Team FORE Critical Design Review Tung Tran Matt Drodofsky Haris Md Ishak Matt Lossmann Mark Koch Ravi Patel Ki-Bom Kim Andrew Martin

2. PresentationOverview • Mission Requirements • Aerodynamics • Aspect and Taper Ratio • Wing Selection Analysis • Structures • Landing Gear • Weight Determination • List of Components • Wing Tip Vertical Deflection • Bending Moment Study • Skin and Material • Propulsion • Motor Selection • Battery Selection • High Speed Flight • Propeller Properties • Motor Properties • Endurance Flight • Propeller Properties • Motor Properties • Dynamics & Control • Tail Surface Sizing • Control Surface Sizing • Yaw Rate Control Feedback system • Build Schedule • Flight Test • Static Test • Dynamic Test

3. Mission Requirements • High Speed Autonomous Unmanned Aircraft • 1 lb payload measuring 2.5x4x3 in • Takeoff and Landing Distance of 120 ft • Minimum Climb Angle 35o • Stall Velocity <= 30 ft/sec • Dutch Roll Damping > 0.8 • Budget Cost $250.00

4. 3 View Drawing

5. 3-D Picture

6. Aspect Ratio • Minimize Drag (Induced vs. Skin Friction) • Skin Friction Drag • Turbulent Flat Plate Approximation • Induced Drag

7. AR=2.1 AR=17 AR=7 Aspect Ratio V = 49 ft/s V = 130 ft/s Wing Span = 5.44 ft @ AR = 7

8. Taper Ratio • Best Taper Ratio: 0.45 (delliptical = 0) [Anderson] • Induced Drag • Fourier Coefficients • d Summation • 1.27% CDi Increase v. Elliptical Lift Distribution

9. Airfoil Selection Reynolds Number ≈ 100,000 • Constraints: Required CLmax at Vstall= 30 ft/s. Reynolds Number ≈ 100,000 Martin Hepperle MH45 Martin Hepperle MH32 Selig/Donovan SD7032 • CLmax required depends on Wing Loading. W/S = 1.29 [ lbf/ft2 ] • 3-D CLmax= 1.21 [with flaps] • 2-D CLmax= 1.09 [without flaps] Source : UiUC Windtunnel Data

10. Airfoil Selection • Coefficient of Drag at Vdash = 130 ft/s: • Profile Coefficient of Drag • From Drag Polar • Coefficient of Induced Drag • Function of Coefficient of Lift Reynolds Number ≈ 300,000 Martin Hepperle MH45 Martin Hepperle MH32 Selig/Donovan SD7032 • Minimum CDi Occurs at the lowest CL: • MH45 has lowest CL at minimum CD Source : UiUC Windtunnel Data

11. Tail Selection • Airfoil Section Chosen to: • Have low drag • Manufacturability • Horizontal Tail • NACA 0009 • Vertical Tail • NACA 0009

12. Wing Analysis • MH45 Wing Analysis [Raymer & Brandt] • Conversion between 2-D and 3-D

13. flapped area over wing area angle of hinge line to center line Flap Analysis • 2-D Analysis in XFOIL • 35o Deflection (0.15c) • Convert to 3-D [Raymer]

14. Landing Gear Analysis • Assumptions: [Raymer] • Main Landing Wheels support 90% of weights. • Taildragger aft tires are about a quarter to a third the size of the main tires. • Tire sizing: • Diameter : 0.1633ft (1.96 in) • Width: 0.075ft (0.9 in)

15. Tip-over Analysis • Longitudinal tip-over analysis [Raymer] • Angles between most aft/most forward CG and main landing gear should be between 16 to 25 degrees. • The tail-down angle should be between 10 to 15 degrees • Lateral tip over analysis • Main wheels should be more than 25 degrees laterally from Center of Gravity.

16. Wing Assembly Leading Edge Wing Mount Complete wing assembly with fiberglass cover

17. Skin Materials Trade Study • Purpose: Compare weight of skin made of different materials • Method: Single cell Thin-walled analysis • Result: Fiber glass has lowest weight

18. Skin & Material • GRP (Glass Reinforced plastic) wing covering (fiber glass w/ epoxy) 3oz E Glass Satin WeaveThickness: 0.0046“ (Two layer 0.0092’’) Epoxy hardener (205(fast) +206(slow)) Epoxy Resin (105)

19. List of Components • Total Weight: • 5.0074 lb • (excluding control wires, hinges and glue)

20. CG Determination • Center of gravity: Y X Center of gravity Moment of inertia (results from CATIA)

21. Bending Moment Study

22. Wing Tip Vertical Deflection Vertical deflection of wing tip 0.1167ft (1.4in)

23. Catia Model • Benefits • Visualization • Moment of Inertia • CG Calculation • Weight Estimation • CNC Manufacturing

24. Battery Selection • A123 Racing Lithium Ion batteries • 5 cells • 70A continuous discharge • 2300mAh per cell • 3.6 V per cell • 70 grams per cell

25. Motor Selection • Motor Information • AXI 2826/10 Gold line • 3-5 lipo cells • Kv - 920 RPM/V • Max Continuous – 30A • Max Burst – 42A • Acceptable Props: 10x8-13x10

26. High Speed Mission High Speed = 130 ft/sec • Propeller Properties • 10 in propeller • 8 in pitch • Advance Ratio - .73 • Propeller Efficiency - .85 • Cp - .0404 • Ct - .0468 • RPM – 12909rpm • Output Power – 327.3 ft-lbf/sec

27. High Speed Mission • Motor Properties • Power Out – 525 watts • Input Current – 39.1A • Input Voltage – 14.2V • RPM – 12908rpm • Motor efficiency - .95

28. Endurance Mission • Fly endurance mission at 49ft/s

29. Endurance Mission • Propeller Properties • 12 in diameter • 8 in pitch • Advance Ratio - .67 • Propeller Efficiency - .85 • Cp - .03 • Ct - .037 • RPM – 4385rpm • Output Power – 23.2 ft-lbf/sec

30. Endurance Mission • Motor Properties • Power Out – 36 watts • Input Current – 9.3A • Input Voltage – 4.8V • RPM – 4385rpm • Motor efficiency - .81 • 51 min flight time

31. Class II Sizing of Tail Area (Horizontal & Vertical Surfaces) MAC = 0.815 ft (9.78 in) CG Range = 0.184MAC – 0.327MAC CG Location = 0.235MAC AC Location = 0.4153MAC Static Margin = 18% Static Margin Range = 14 % Sh = 1.0 ft2 Longitudinal Static Stability Cmα=-1.6265 rad-1 Usually negative Sv = 0.4 ft2 Weathercock Stability Cnβ=0.10193 rad-1 typically 0.06 to 0.2 Roskam

32. Summary

33. Control Surfaces Historical Data: Cessna Skywagon Trim Diagram [Roskam] • Horizontal Stabilizer Incidence Angle = -1o • Max Trim Elevator Deflection Angle = -15o • High Speed CL = 0.08 Pitch, elevator size Cmδe=-2.6408 typically -1 to -2 Yaw and/or roll, rudder size Cnδr=-0.1002 typically -0.06 to -0.12 Roll, flaperon size Clδa=0.285 typically 0.05 to 0.2

34. Modal ParametersOpen Loop • Phugoid mode • Damping Ratio: 0.495 • Natural Frequency: 0.2582 rad/sec • Short Period mode • Damping Ratio: 0.934 • Natural Frequency: 13.248 rad/sec • Dutch Roll mode • Damping Ratio: 0.2014 • Natural Frequency: 8.355 rad/sec • Roll mode • Time Constant: 0.49 sec • Spiral mode • Time Constant: 54.91 sec Ogata

35. Dutch Roll Feedback Block Diagram • Nominal Gain: -0.11 • Dutch Roll closed loop • Damping Ratio: 0.841 • Natural Frequency: 10.9 rad/sec Aircraft and Servo Transfer Function Aircraft Transfer Function Servo Transfer Function

36. Root Locus of Control System • Closed Loop Poles for Yaw Rate feedback to Rudder

37. Build Schedule

38. Flightline Tests Static Test(Purdue Airport) Rate Gyro Gain setting – Correct Deflection Transmitter Receiver operation Control Surface operation Propulsion operation Dynamic Test(McAllister Park) Taxi Run – Landing Gear and Tail Wheel controllability Rate Gyro Gain setting – Correct Magnitude First flight: (Yaw feedback control off) Brief liftoff and land to feel initial handing qualities of aircraft Second flight: Sustaining flight with turns to evaluate aircraft stability and control Third flight: Go through procedures to set rate gyro gain. FULL THROTTLE FLIGHT!

39. References • Brandt, Steven. Et al. Introduction to Aeronautics: A Design Perspective. 1997. • Raymer, D. Aircraft Design: A Conceptual Approach. Forth Edition. 2006. • Stevens, B., Lewis, F. Aircraft Control and Simulation. 2003. • Anderson, J. Fundamentals of Aerodynamics. 2001. • Callister, W. D. Material Science & Engineering 2nd edition. 2005. • Sun, C. T. Mechanics of Aircraft Structures. 1998.

40. Questions?