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 December 6, 2005

OVERVIEW  Problem Statement  Design Specifications  Project Planning  Design Selection  Procedure for Design  Cost Analysis  Spring Proposal  Conclusion

Problem Statement  To design a means of testing MAV flight dynamics in an indoor facility

Project Specs  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

Design Selection: Free Flight Wind Tunnel  The free flight wind tunnel has been successfully created before  Design is basically a conventional wind tunnel modified to allow for actual free flight of the test subject  Force balance achieved around the center of gravity of the MAV, essentially canceling out the force from the incident wind tunnel flow with the thrust of the engine

Project Planning  Final design analysis divided into 3 section: –Tunnel geometry  Design of wind tunnel ducting  Selection of fan flow  Settling screen and honeycomb selection –Instrumentation  Onboard measurement  Data collection/display –MAV handling  Control and release of the MAV inside the tunnel

Project Planning: Flow Chart

Design Procedure  Design Procedure is broken down into five main sections: –Wind Tunnel Design –Flow Quality –Flow Fan –Instrumentation –MAV Handling

Wind Tunnel Design  In wind tunnel design Three properties are most important to consider: –Test section Dimensions –Flow quality –Tunnel geometry

Wind Tunnel Design: Test section Dimensions  At its maximum area, wind tunnel must be 6 times that of the test section  The test section should give ample area for the MAV to fly  For the minimum analysis of the flight, the MAV needs to move laterally or vertically twice its wingspan

Wind Tunnel Design: Test section Dimensions (continued)  For the largest MAV (12” wingspan) to be tested in tunnel we would need 2 feet of flying area in any given direction or roughly a 4ft x 4ft test section  When moving longitudinally against the flow we will allow for 10ft of movement for the MAV

Wind Tunnel Design: Flow Quality  The quality of the flow for our application is based on velocity fluctuations in the direction of the airflow  Need a flow quality that has velocity fluctuations of less than 1% of the free flow  Screens and a honeycomb are implemented to take out the rotational and velocity fluctuations of the flow that form when the air passes through the fan

Wind Tunnel Design: Flow Quality (Continued)  The most important factor to flow quality is the contraction ratio  The larger the contraction ratio, the slower the air flow is when it passes through the screens and honeycomb  For a contraction ratio of 6, combined with the screens and honeycomb, we can achieve a flow quality of less than 1%

Wind Tunnel Design: Tunnel Geometry  Two different tunnel Geometries are explored –Ideal wind tunnel –Constrained wind tunnel

Wind Tunnel Design: Tunnel Geometry – Ideal tunnel  Larger tunnel overall  Utilizes full test section and contraction ratio  Implements a 4.5*4.5 ft test section to compensate for Boundary phenomenon ( only 80% of area is usable)  Test section has length of 10 ft

Wind Tunnel Design: Tunnel Geometry – Ideal tunnel (continued)  *ADD ADDITIONAL INFO*

Wind Tunnel Design: Tunnel Geometry – Constrained tunnel  Designed to fit inside the space currently provided at Eglin AFB (room measuring 40x30x15 ft )  Only aspect of the ideal tunnel that is too large for the room is the tunnel length  Need to shorten the tunnel by 21.3 ft

Wind Tunnel Design: Tunnel Geometry – Constrained tunnel (Continued)  *ADD ADDITIONAL INFO*

Flow Quality  Flow quality will be of paramount importance in tunnel design

Free Flight Diagram

Wind Tunnel Geometry  Area required to fly 4 ft x 4 ft  Test section area is 4.5 ft x 4.5 ft  Test section length greater than 10 ft

Wind Tunnel Geometry  Fan Specifications –Mass flow rate: 60.8 kg/s –Ideal power needed: 50 hp –Diameter of fan: 7.1 ft

Wind Tunnel Geometry  Final Expansion –Final area is 8 times test section area

Wind Tunnel Geometry

Tether System  Tether Location  Tether Restraint and Release System  Tether Reel

Tether Location  Above and below MAV’s center of mass

Restraint and Release System  Tether Clamp

Tension Reel  Miyamae's Command X-1

Instrumentation  Onboard  Flow Measurement  Data Collection Software

Onboard Instrumentation  Kestrel Autopilot –16.65 grams (2” x 1.37” x.47”) –Three-axis rate gyros –Accelerometers –Air pressure sensors

Flow Measurement  Pitot-Static Tube  Hot-Wire Anemometer

Data Collection Software  Virtual Cockpit  Labview

On-Going Activities  Source the Fan  Find manufacturer to produce settling screens  Create Bill of Materials  Build Pro-E model of system