Patent US 9,193,451

A vehicle incorporating a hybrid propulsion system. In one form, the vehicle may be an aircraft such that the system includes gas turbine engines as a first motive power source, and one or more battery packs as a second motive power source. Through selective coupling to an electric motor that can in turn be connected to a bladed rotor or other lift-producing device, the motive sources provide differing ways in which an aircraft can operate. In one example, the gas turbine engines can provide operation for a majority of the flight envelope of the aircraft, while the battery packs can provide operation during such times when gas turbine-based motive power is unavailable or particularly disadvantageous. In another example, both sources of motive power may be decoupled from the bladed rotor such that the vehicle can operate as an autogyro. In another mode of operation, the movement of a bladed rotor can be both decoupled from the sources of propulsion as well as fixed relative to the aircraft such that the aerodynamic surfaces formed on the bladed rotors can act as a fixed wing. In another particular form, the vehicle may be ground-based or water-based.