UAV Research International

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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

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OVERVIEW

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

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Problem Statement

• To design a means of testing MAV flight dynamics
  in an indoor facility

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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

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Design SelectionFree 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

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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

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Project Planning Flow Chart
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Design Procedure

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

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Wind Tunnel Design

• In wind tunnel design Three properties are most
  important to consider
• Test section Dimensions
• Flow quality
• Tunnel geometry

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Wind Tunnel DesignTest 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

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Wind Tunnel DesignTest 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

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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

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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

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Wind Tunnel Design Tunnel Geometry

• Two different tunnel Geometries are explored
• Ideal wind tunnel
• Constrained wind tunnel

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Wind Tunnel Design Tunnel Geometry Ideal
tunnel

• Larger tunnel overall
• Utilizes full test section and contraction ratio
• Implements a 4.54.5 ft test section to
  compensate for Boundary phenomenon ( only 80 of
  area is usable)
• Test section has length of 10 ft

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Wind Tunnel Design Tunnel Geometry Ideal
tunnel (continued)

• ADD ADDITIONAL INFO

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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

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Wind Tunnel Design Tunnel Geometry
Constrained tunnel (Continued)

• ADD ADDITIONAL INFO

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Flow Quality

• Flow quality will be of paramount importance in
  tunnel design

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Free Flight Diagram
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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

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Wind Tunnel Geometry

• Fan Specifications
• Mass flow rate 60.8 kg/s
• Ideal power needed 50 hp
• Diameter of fan 7.1 ft

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Wind Tunnel Geometry

• Final Expansion
• Final area is 8 times test section area

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Wind Tunnel Geometry
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Tether System

• Tether Location
• Tether Restraint and Release System
• Tether Reel

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Tether Location

• Above and below MAVs center of mass

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Restraint and Release System

• Tether Clamp

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Tension Reel

• Miyamae's Command X-1

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Instrumentation

• Onboard
• Flow Measurement
• Data Collection Software

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Onboard Instrumentation

• Kestrel Autopilot
• 16.65 grams (2 x 1.37 x .47)
• Three-axis rate gyros
• Accelerometers
• Air pressure sensors

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Flow Measurement

• Pitot-Static Tube
• Hot-Wire Anemometer

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Data Collection Software

• Virtual Cockpit
• Labview

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On-Going Activities

• Source the Fan
• Find manufacturer to produce settling screens
• Create Bill of Materials
• Build Pro-E model of system

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