1. UAV Research International “Providing integrated consultation to MAV project engineers at Eglin AFB” Chris McGrath Neil Graham Alex von Oetinger John Dascomb Sponsor : Dr. Gregg Abate April 6, 2006

2. Overview  Problem Statement  Design Specifications  Design Solution  Scale Model Design/Fabrication  Testing

3. Problem Statement  To design a means of characterizing MAV handling during flight  Test must be repeatable  Data must be collected to characterize the MAV

4. Project Specifications  Weight  100 – 200 grams (g)  Flight Speed  0 – 25 meters per second (m/s)  Exterior Material  Carbon Fiber Composite  Wing Tip Length  15 – 30 centimeters (cm)  MAV Flight Control  Both 2 and 3 axis  Type of Thrust  Pusher, Puller, None

5. Design Selection: Free Flight Wind Tunnel  The free flight wind tunnel has been successfully created before  Design is a conventional wind tunnel with unobstructed test section  Relative velocity of MAV to the ground is zero

6. MAV Handling: Initial Set-up

7. MAV Handling: Reel and Restraint Set-up

8. Wind Tunnel Design  In wind tunnel design Three properties are most important to consider: –Tunnel geometry –Flow quality –Fan Selection

9. Wind Tunnel Design

10. Wind Tunnel Geometry: Test section Dimensions  For the minimum analysis of the flight, the MAV needs to move laterally or vertically twice its wingspan  Minimum cross section for 12” wingspan is 4.5 ft x 4.5 ft  Allow ten feet for longitudinal motion

11. Wind Tunnel Geometry

12. Wind Tunnel Geometry: 1 st Diffuser  Expands the ducting from area of test section to the area of the fan  Diffuser angle < 5° for laminar flow

13. Wind Tunnel Geometry

14. Wind Tunnel Design: Turns 1 and 2  Corner Vanes assist flow around the 4 90 degree turns  Corner Vanes improve efficiency by decreasing pressure loss  Even with vanes 61% of all pressure loss occurs at the 1 st two turns

15. Wind Tunnel Geometry

16. Wind Tunnel Design: Fan Selection  Fan selection based on volume flow rate and static pressure loss in tunnel  Volume flow rate at maximum of 25 m/s is 100000 CFM  Total pressure loss in tunnel = 600 Pa

17. Wind Tunnel Design: Fan Selection  Howden Buffalo 54-26 series fan  Fan has a 54 in diameter, and a 125 HP motor

18. Wind Tunnel Design: Flow Quality  Motor housing  Anti-swirl vanes

19. Wind Tunnel Geometry

20. Wind Tunnel Geometry: 2 nd Diffuser, Turns 3 and 4  Diffuser increases area final area ratio of 6  Final area ratio is most important factor in tunnel  Turning vanes keep flow as laminar as possible

21. Wind Tunnel Geometry

22. Wind Tunnel Design: Flow Quality  Honeycombs - remove lateral components of turbulence  3 Screens – remove axial components of turbulence

23. Wind Tunnel Geometry: Contraction Cone  Contraction cone quickly increases flow velocity  When condensing, flow will not separate like diffuser

24. Wind Tunnel Geometry : Tunnel Geometry – Constrained tunnel Total tunnel length is 36.6 ft

25. Instrumentation  On-Board Measurement  Flow Quality Measurement  Traversing System  Data Collection Software  Data Acquisition System

26. On-Board Measurement  Kestrel Autopilot –16.65 grams (2” x 1.37” x.47”) –Three-axis rate gyros –Accelerometers –Air pressure sensors

27. Data Collection Software  Virtual Cockpit  Labview

28. Cost Analysis

29. Scale Model  Too expensive to build the designed tunnel  Built a 1/12 scale model  Physically test flow quality of full scale design to determine if free flight is feasible

30. Scale Effects  Scale model Reynolds number 1/12 that of full scale model  Use hot-wire Anemometer to measure velocity fluctuation though test section  Velocity is not dependent on Reynolds number, scaling effects can be ignored for our tests

31. Scale Model

32. Contraction Cone

33. Total Elapsed Time: 2 Hours 20 Hours

34. Contraction Cone Total Elapsed Time: 41 Hours

35. Contraction Cone

36. Joining Method

37. Turning Vanes

38. Diffusers

39. Settling Chamber

40. Fan

41. Model Results  Manufacturing Complete  Testing –Initial correction of flow through turning vanes –Inconclusive analysis of tunnel due to lack of testing  Potential Testing –Fine tune internal geometry –Correction of all Turning vanes –Measuring Pressure fluctuations through test section

42. Problems Encountered  Wait time on ordered parts  MSC acrylic sheets  McMaster-Carr fan order  Fabrication of contraction cone  Testing Time Constraints

43. Questions?