HYBRID TURBOFAN AND SOLID OXIDE FUEL CELL PROPULSION SYSTEM AND RELATED METHODS

Hybrid propulsion systems that utilize liquid natural gas solid oxide fuel cells in a manner practical for use in aircraft that avoid the use of heavy batteries, provide transient response times suitable for use in aircraft, and/or simplify reactant pre-conditioning systems using a compressor and turbine pair operatively coupled to the solid oxide fuel cell. Such hybrid propulsion systems for an aircraft may include a liquid natural gas solid oxide fuel cell, a motor driven by electric power from the solid oxide fuel cell, a gearbox operatively coupled to the motor, and a turbofan engine configured to generate thrust for the aircraft. The turbofan engine may be configured to provide electric power and shaft power and may include a duct fan that is operatively coupled to the motor via the gearbox, with the duct fan being driven by mechanical power from the gearbox and by the motor.