HYBRID TURBOSHAFT 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 turboshaft engine, a turbo generator operatively coupled to the turboshaft engine, a liquid natural gas solid oxide fuel cell, and an electric fan. The electric fan may be configured to generate thrust for the aircraft and may be powered by the turbo generator and/or the solid oxide fuel cell. Fuel cell reactants may be pre-conditioned using turboshaft bleed air, and the liquid natural gas may be pre-heated by fuel exhaust from the solid oxide fuel cell.