Helicopter Rotor with Flexible Hub

The paper discusses an improved control system for a helicopter or VTOL aircraft equipped with a rigid lift rotor integral with a flexible hub.

The proposed method consists in suitably arranging the knuckle joints on the ends of the blade pitch control levers to create a complementary cyclic deflection effect which is dependent upon the rotor's attitude and is superimposed upon the pilot's control.

The reduced dynamic instability of the helicopter with the control column locked, and the calculated improvement in the rotor's response to the control column facilitates piloting.

The control of such a helicopter compares with driving an automobile equipped with servo-assisted controls.