Abstract: An improved autogyro including a main airframe having a main engine and pusher propeller as customarily applied in autogyros, and a lifting rotor having an auxiliary drive for the lifting rotor for tapping a minor portion of power from the main propulsive engine and transmitting it to the rotor, including a three-stage compound mechanical-hydraulic transmission for transferring power from the main engine to the lift rotor, wherein the hydraulic portion of the transmission serves functions of providing continuously variable transmission speed ratio, torque converter type of inverse speed-torque relationship, a one-way check valve allowing the rotor to free-wheel, an overpressure relief valve to prevent overtorquing of the lift rotor, a bypass valve acting as a clutch to engage and disengage the power, and a manual shut-off valve acting as a rotor brake and rotor parking lock.