In 1939 O L Stauffer of Elkhart IN., USA, built a single-place gyrocopter on which the revolving upper wing locked in place to convert the aircraft into a biplane.
Stauffer Gyroplane
In 1939 O L Stauffer of Elkhart IN., USA, built a single-place gyrocopter on which the revolving upper wing locked in place to convert the aircraft into a biplane.
All Aero 