Downwash Vortices

A Cessna Citation was flown above a cloud bank over Lake Tahoe at approximately 165 knots. The trailing vortices decended over the fog layer due to downwash, and were made visible by the distortion at the interface.

This photo was taken from the tail gunner's position in a B-25 flying in formation slightly above and ahead of the Cessna. The Cessna is initiating a climb after a slow level flight.

Aircraft Data

• Velocity = 165 knots
• Wing Area = 29 m^2
• Wing Span = 16 m
• Mean Aerodynamic Chord = 2 m
• Weight = 8000 kg
• Chord Reynolds Number = 1.18E7