US Patent 11001390 Helicopter hybrid engine system

A helicopter may include a hybrid engine system including an internal combustion engine (e.g., a turbine engine) and an electric engine. The internal combustion engine and the electric engine being coupled to the rotor system and configured to separately or collectively operate the rotor system in response to a triggering event. In one aspect, a method for operating a rotor system of a helicopter may include receiving an indicator of a triggering event and actuating a non-active engine, one of the internal combustion engine or the electric engine, in response to receiving the triggering event.