Investigations of Hingeless Rotor Stability

An overview of the technical development of hingeless and bearingless rotors is given, with emphasis on aeroelastic and aeromechanical stability characteristics. Important considerations for theoretical analysis are discussed. Theoretical and experimental investigations of isolated blade flap-lag and flap-lag-torsion stability, and coupled rotor-body aeromechanical stability are described. Physical interpretation and important rotor system design parameters are emphasized. An overview of bearingless rotor dynamics is also included.