Abstract:

The main rotor is in the condition of autorotation w hen a gyroplane is in flight or a helicopter in autorotation. After an aerodynamic model of a autorotating rotor was established, the conclusion is drawn that the autorotating rotor of the gyroplane has a better aerodynamic condition and hig her efficiency compared with the rotor of the helicopter.The analysis of the relations among steady rotary speed, collective pitch, forward speed and rotor disk angle of attack showed that a regular collective pitch and rotary speed can be selected to fit steady flight in a considerable wide range of flight speed only by adjusting the rotor disk angle of attack a little.

Key words: autor ota ting r ot or, g yr oplane, aero dy namic perfo rmance, steady r o tary speed