A fuel cell system includes: a gas turbine having a combustion chamber and a turbine; a hydrogen fuel cell configured to generate electrical energy from input air and input hydrogen; an air flow path for providing air from a source of fresh air as input air to the fuel cell and to the combustion chamber; and a closed hydrogen loop for providing hydrogen from a liquid or compressed hydrogen source to the fuel cell and to the combustion chamber. The system further includes: a hydrogen recirculation loop receiving hydrogen from the liquid or compressed hydrogen source and hydrogen used by the fuel cell to provide cooled used hydrogen, The hydrogen recirculation loop combines the cooled used hydrogen with hydrogen from the liquid or compressed hydrogen source to provide to the fuel cell as the input hydrogen.

A fuel cell system includes: a gas turbine having a combustion chamber and a turbine; a hydrogen fuel cell configured to generate electrical energy from input air and input hydrogen; an air flow path for providing air from a source of fresh air as input air to the fuel cell and to the combustion chamber; and a closed hydrogen loop for providing hydrogen from a liquid or compressed hydrogen source to the fuel cell and to the combustion chamber. The system further includes: a hydrogen recirculation loop receiving hydrogen from the liquid or compressed hydrogen source and hydrogen used by the fuel cell to provide cooled used hydrogen, The hydrogen recirculation loop combines the cooled used hydrogen with hydrogen from the liquid or compressed hydrogen source to provide to the fuel cell as the input hydrogen.

An electromechanically controlled aircraft power transmission system includes a first planetary gear set, a first gas turbine engine, a first electric machine, a second planetary gear set, a second gas turbine engine, a second electric machine, a propulsor shaft, and at least one propulsor. The first gas turbine engine is coupled to the first planetary gear set. The first electric machine is coupled to the first planetary gear set and is configured vary the gear ratio of the first planetary gear set. The second gas turbine engine is coupled to the second planetary gear set. The second electric machine is coupled to the second planetary gear set and is configured to vary the gear ratio of the second planetary gear set. The propulsor shaft is coupled to the first and second planetary gear sets and the at least one propulsor is coupled to the propulsor shaft.

An electric machine adapted for use in a gas turbine engine includes a shaft extending along a central axis, a magnetic rotor drum, and a non-magnetic rotor hub rotatably coupled with the shaft and the magnetic rotor drum. The magnetic rotor drum includes a rotor and a plurality of magnets arranged circumferentially about the central axis.

A hybrid power and propulsion system of a vehicle is provided and includes an engine assembly coupled to a common bus via a first plug type and including a motor-generator configured to generate electricity, a storage element coupled to the common bus via a second plug type and configured to store the electricity, a drive assembly coupled to the common bus via a third plug type and configured to receive the electricity from at least one of the engine assembly or the storage element to drive a propulsive fan and a controller. The controller is connected to the common bus and controls a flow of the electricity between at least one of the engine assembly, the storage element and the drive assembly. The common bus is configured with additional connectors of the second and third plug types to enable removable connections of additional storage elements and drive assemblies.

A distributed hybrid propulsion system is provided and includes an engine assembly that includes an engine, which is non-propulsive, an energy storage element, a motor-generator and a common bus to which the engine assembly, the energy storage element, the motor-generator and the controller are connected. The common bus includes bi-directional power flow control elements, which are controllable to manage bi-directional power flow between the engine assembly, the energy storage element and the motor-generator.

The power plant can have a structure; an output shaft connectable to a load, the output shaft rotatable about an axis relative the structure; a thermal engine secured to the structure, the thermal engine having a thermal engine shaft; an electric motor having a stator and a rotor shaft, the stator secured to the structure; an epicyclic gearing having a sun gear coaxial to a ring gear, a plurality of planet gears meshed between the sun gear and the ring gear, and a carrier coaxial to the sun gear and to the ring gear, the sun gear, carrier, and ring gear being rotatable relative the casing structure, the output shaft and the rotor shaft both coupled to the carrier, and the thermal engine shaft coupled to sun gear and the carrier; and an overrunning clutch operable to prevent the rotation of the ring gear in one angular direction.

The power plant can have a structure; an output shaft connectable to a load, the output shaft rotatable about an axis relative the structure; a thermal engine secured to the structure, the thermal engine having a thermal engine shaft; an electric motor having a stator and a rotor shaft, the stator secured to the structure; an epicyclic gearing having a sun gear coaxial to a ring gear, a plurality of planet gears meshed between the sun gear and the ring gear, and a carrier coaxial to the sun gear and to the ring gear, the sun gear, carrier, and ring gear being rotatable relative the casing structure, the output shaft and the rotor shaft both coupled to the carrier, and the thermal engine shaft coupled to sun gear and the carrier; and an overrunning clutch operable to prevent the rotation of the ring gear in one angular direction.

Hybrid-electric aircraft and a series hybrid powertrain configured to power the aircraft for a medium-haul flight. The series hybrid power train includes a plurality of energy storage units, at least one range extending generator, and a plurality of electric propulsors, each coupled to a distribution bus. The electric propulsors can produce a maximum thrust of at least 15 MW. During a cruise regime, the hybrid-electric aircraft can have an airspeed of at least 0.7 Mach at an altitude of less than 32000 feet, and the plurality of electric propulsors can have a fan pressure ratio of between 1.15 and 1.19. The hybrid-electric aircraft can have a degree of hybridization of at least 25% for the medium-haul flight and carbon dioxide equivalent (CO.sub.2e) well-to-wake greenhouse gas (GHG) emissions less than 0.25 lbs/Available Seat Mile (ASM).

Hybrid-electric aircraft and a series hybrid powertrain configured to power the aircraft for a medium-haul flight. The series hybrid power train includes a plurality of energy storage units, at least one range extending generator, and a plurality of electric propulsors, each coupled to a distribution bus. The electric propulsors can produce a maximum thrust of at least 15 MW. During a cruise regime, the hybrid-electric aircraft can have an airspeed of at least 0.7 Mach at an altitude of less than 32000 feet, and the plurality of electric propulsors can have a fan pressure ratio of between 1.15 and 1.19. The hybrid-electric aircraft can have a degree of hybridization of at least 25% for the medium-haul flight and carbon dioxide equivalent (CO.sub.2e) well-to-wake greenhouse gas (GHG) emissions less than 0.25 lbs/Available Seat Mile (ASM).