Wing Rock and other Roll Phenomena

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Wing Rock and other RollPhenomena
by Robert C. Nelson November 11, 2005
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• What is Wing Rock?
• A limit cycle rolling motion.
• Can occur during low a transonic maneuvers.
• Can occur at high a subsonic maneuvers.
• Why is it significant?
• Highly swept wings are susceptable.
• Many aircraft exhibit the phenomena.
• Degrades tracking capability.
• Safety issue during landing approarch.

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Aircraft That have Experienced a Wing Rock motion
Aircraft that are known to have a wing rock
motion.

• X 29
• X 31
• Gnat Trainer
• Tornado
• Harrier

• A - 4 Skyhawk
• F - 4 Phantom
• F - 5 Tiger
• F - 14 Tomcat
• F - 16 Fighting Falcon
• F - 18 Hornet

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Wing Rock Time History

• a 30o f 0o

Phase Plane Diagram
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A Unique Free to Roll Systems

• Sting/Air Bearing System with optical encoder.
• Air bearing reduces mechanical friction by an
  order of magnitude.
• Optical encoder provides accurate roll time
  history data of wing rock motion or other rolling
  phenomena.
• Free to Roll Simulator
• Unsteady pressure data was obtained using the
  wing rock simulator.
• By replacing the air bearing with a DC servo
  motor the wing rock motion could be duplicated.
  The free to roll motion was downloaded to a
  computer incorporating a motion control card so
  that the servo motor could be controlled to
  replicate the measured wing rock motion.