Abstract: A gas turbine engine includes a compressor section having a first compressor and a second compressor, the second compressor having a higher pressure than the first compressor, and a turbine section having a first turbine and a second turbine, the second turbine having a higher pressure than the first turbine. The first compressor is connected to the first turbine via a first shaft. The second compressor is connected to the second turbine via a second shaft. An electric motor is connected to the first shaft such that rotational energy generated by the electric motor is translated to the first shaft. A fan is connected to the first shaft via a gear system. The gas turbine engine includes at least a takeoff mode of operations, a top of climb mode of operations and a maximum cruise mode of operations. The gas turbine engine is sized to operate at peak efficiency in the maximum cruise mode of operations.

Abstract: A gas turbine engine includes a compressor section having a first compressor and a second compressor, the second compressor having a higher pressure than the first compressor, and a turbine section having a first turbine and a second turbine, the second turbine having a higher pressure than the first turbine. The first compressor is connected to the first turbine via a first shaft. The second compressor is connected to the second turbine via a second shaft. An electric motor is connected to the first shaft such that rotational energy generated by the electric motor is translated to the first shaft. A fan is connected to the first shaft via a gear system. The gas turbine engine includes at least a takeoff mode of operations, a top of climb mode of operations and a maximum cruise mode of operations. The gas turbine engine is sized to operate at peak efficiency in the maximum cruise mode of operations.

Abstract: An engine-driven cryogenic cooling system for an aircraft includes a first air cycle machine, a second air cycle machine, and a means for condensing a chilled air stream into liquid air for an aircraft use. The first air cycle machine includes a plurality of components operably coupled to a gearbox of a gas turbine engine and configured to produce a cooling air stream based on a first engine bleed source of the gas turbine engine. The second air cycle machine is operable to output the chilled air stream at a cryogenic temperature based on a second engine bleed source cooled by the cooling air stream of the first air cycle machine.

Abstract: A gas turbine engine includes a compressor section and a turbine section operably coupled to the compressor section. The gas turbine engine further includes a means for selectively releasing a cooling fluid flow produced at a cryogenic temperature and a plumbing system in fluid communication with the means for selectively releasing the cooling fluid flow. The plumbing system is configured to route the cooling fluid flow to one or more of the compressor section and the turbine section.

Abstract: A powertrain system of an aircraft includes one or more electrical components to provide electrical power to one or more electrical loads of the aircraft. The system further includes a rechargeable cryogenic heat sink containing a volume of cryogenic cooling material. The cryogenic heat sink is configured to cool the one or more electrical components. A method of operating a powertrain system of an aircraft includes generating thermal energy at one or more electrical components of the powertrain system, fluidly connecting a cryogenic heat sink to the one or more electrical components, and cooling the one or more electrical components via a volume of cryogenic cooling material of the cryogenic heat sink.

Abstract: A powertrain system of an aircraft includes one or more electrical components to provide electrical power to one or more electrical loads of the aircraft. The system further includes a rechargeable cryogenic heat sink containing a volume of cryogenic cooling material. The cryogenic heat sink is configured to cool the one or more electrical components. A method of operating a powertrain system of an aircraft includes generating thermal energy at one or more electrical components of the powertrain system, fluidly connecting a cryogenic heat sink to the one or more electrical components, and cooling the one or more electrical components via a volume of cryogenic cooling material of the cryogenic heat sink.

Abstract: Aircraft propulsion systems have aircraft systems including at least one hydrogen tank and an aircraft-systems heat exchanger and engine systems includes at least a main engine core, a high pressure pump, a hydrogen-air heat exchanger, and a turbo expander. The main engine core includes a compressor section, a combustor section having a burner, and a turbine section arranged along an engine shaft. Hydrogen is supplied from the at least one hydrogen tank through a hydrogen flow path, passing through the aircraft-systems heat exchanger, the high pressure pump, the hydrogen-air heat exchanger, and the turbo expander, prior to being injected into the burner for combustion. The turbo expander is configured to impart power to the engine shaft.

Abstract: A propulsion system includes a core engine generating a high energy gas flow, a condenser configured to extract water from the high energy gas flow and an evaporator transforming the extracted water into a steam flow. The steam flow is injected into a core flow path of the core engine increase mass flow.

Abstract: A turbine engine system includes at least one hydrogen fuel tank, a core flow path heat exchanger in a core flow path; and engine systems located in the core flow path. The engine system including at least a compressor section, a combustor section having a burner, and a turbine section. The core flow path heat exchanger is arranged in the core flow path downstream of the combustor section. The hydrogen fuel is supplied from the at least one hydrogen fuel tank through a hydrogen fuel supply line, passing through the core flow path heat exchanger and then supplied into the burner for combustion.

Abstract: Aircraft propulsion systems and aircraft are described. The aircraft propulsion systems include aircraft systems having at least one hydrogen tank and an aircraft-systems heat exchanger and engine systems having at least a main engine core, a high pressure pump, a hydrogen-air heat exchanger, and an expander, wherein the main engine core comprises a compressor section, a combustor section having a burner, and a turbine section. Hydrogen is supplied from the at least one hydrogen tank through a hydrogen flow path, passing through the aircraft-systems heat exchanger, the high pressure pump, the hydrogen-air heat exchanger, and the expander, prior to being injected into the burner for combustion.

Abstract: Aircraft propulsion systems include aircraft systems having at least one hydrogen tank and an aircraft-systems heat exchanger and engine systems having at least a main engine core, a high pressure pump, a hydrogen-air heat exchanger, and a turbo expander. The main engine core includes a compressor section, a combustor section having a burner, and a turbine section. Hydrogen is supplied from the at least one hydrogen tank through a hydrogen flow path, passing through the aircraft-systems heat exchanger, the high pressure pump, the hydrogen-air heat exchanger, and the turbo expander, prior to being injected into the burner for combustion. The turbo expander includes a rotor separated into a first expander portion and a second expander portion arranged about an output shaft and the output shaft is operably connected to a generator configured to generate electrical power.

Abstract: A gas turbine engine includes a core having a compressor section with a first compressor and a second compressor, a turbine section with a first turbine and a second turbine, and a primary flowpath fluidly connecting the compressor section and the turbine section. The first compressor is connected to the first turbine via a first shaft, the second compressor is connected to the second turbine via a second shaft, and a motor is connected to the first shaft such that rotational energy generated by the motor is translated to the first shaft. The gas turbine engine includes a takeoff mode of operation, a top of climb mode of operation, and at least one additional mode of operation. The gas turbine engine is undersized relative to a thrust requirement in at least one of the takeoff mode of operation and the top of climb mode of operation, and a controller is configured to control the mode of operation of the gas turbine engine.

Abstract: Aircraft propulsion systems have aircraft systems including at least one hydrogen tank and an aircraft-systems heat exchanger and engine systems includes at least a main engine core, a high pressure pump, a hydrogen-air heat exchanger, and a turbo expander. The main engine core includes a compressor section, a combustor section having a burner, and a turbine section arranged along an engine shaft. Hydrogen is supplied from the at least one hydrogen tank through a hydrogen flow path, passing through the aircraft-systems heat exchanger, the high pressure pump, the hydrogen-air heat exchanger, and the turbo expander, prior to being injected into the burner for combustion. The turbo expander is configured to impart power to the engine shaft.

Abstract: Aircraft propulsion systems include aircraft systems having at least one hydrogen tank and an aircraft-systems heat exchanger and engine systems having at least a main engine core, a high pressure pump, a hydrogen-air heat exchanger, and a turbo expander. The main engine core includes a compressor section, a combustor section having a burner, and a turbine section. Hydrogen is supplied from the at least one hydrogen tank through a hydrogen flow path, passing through the aircraft-systems heat exchanger, the high pressure pump, the hydrogen-air heat exchanger, and the turbo expander, prior to being injected into the burner for combustion. The turbo expander includes a rotor separated into a first expander portion and a second expander portion arranged about an output shaft and the output shaft is operably connected to a generator configured to generate electrical power.

Abstract: A propulsion system includes a core engine generating a high energy gas flow, a condenser configured to extract water from the high energy gas flow and an evaporator transforming the extracted water into a steam flow. The steam flow is injected into a core flow path of the core engine increase mass flow.

Abstract: An aircraft includes a fuselage defining a longitudinal axis between a forward end and an aft end. The aircraft includes an electrical system having an electric storage. The electric storage is positioned within the fuselage.

Abstract: A gas turbine engine includes a compressor section and a turbine section operably coupled to the compressor section. The gas turbine engine further includes a means for selectively releasing a cooling fluid flow produced at a cryogenic temperature and a plumbing system in fluid communication with the means for selectively releasing the cooling fluid flow. The plumbing system is configured to route the cooling fluid flow to one or more of the compressor section and the turbine section.

Abstract: Aircraft propulsion systems and aircraft are described. The aircraft propulsion systems include aircraft systems having at least one hydrogen tank and an aircraft-systems heat exchanger and engine systems having at least a main engine core, a high pressure pump, a hydrogen-air heat exchanger, and an expander, wherein the main engine core comprises a compressor section, a combustor section having a burner, and a turbine section. Hydrogen is supplied from the at least one hydrogen tank through a hydrogen flow path, passing through the aircraft-systems heat exchanger, the high pressure pump, the hydrogen-air heat exchanger, and the expander, prior to being injected into the burner for combustion.

Abstract: A battery thermal management system for an air vehicle includes a first heat exchange circuit, a battery in thermal communication with the first heat exchange circuit, and a heat exchanger positioned on the first heat exchange circuit. The heat exchanger is operatively connected to a second heat exchange circuit. The system includes a controller operatively connected to the second heat exchange circuit. The controller is configured to variably select whether heat will be rejected to the second heat exchange circuit. A method for controlling a thermal management system for an air vehicle includes determining an expected fluid temperature of fluid in a fluid heat exchange circuit. The method includes commanding a flow restrictor at least partially closed or commanding the flow restrictor at least partially open.

Abstract: An aircraft includes a fuselage defining a longitudinal axis between a forward end and an aft end. The aircraft includes an electrical system having an electric storage. The electric storage is positioned within the fuselage.