A gas turbine engine includes a turbomachine comprising a low pressure (LP) spool and a high pressure (HP) spool that rotate about a central axis, an electric motor mechanically coupled to the LP spool for selectively rotating the LP spool, a starter assembly mechanically coupled to the HIP spool for selectively rotating the HP spool, and a controller in operative communication with the electric motor and the starter assembly, the controller being configured to operate the electric motor to rotate the LP spool and operate the starter assembly to rotate the HIP spool during engine startup.

A method for controlling a thermal and electrical power plant for setting in motion at least one rotary member of a rotorcraft, the power plant comprising at least one heat engine and an electrical system provided with at least one electric machine. The method comprises: selecting, with a selector, an operating mode chosen from several operating modes; determining a density altitude and comparing, with a controller, the current density altitude and a threshold density altitude; and controlling, with the controller, the at least one electric machine depending on at least the chosen operating mode as well as the comparison and a necessary power to be supplied to the power transmission system.

A combustion section includes a casing that defines a diffusion chamber. The combustion section further includes a combustion liner that is disposed within the diffusion chamber and that defines a combustion chamber. The combustion liner is spaced apart from the casing such that a passageway is defined between the combustion liner and the casing. The combustion section further includes a fuel cell assembly that is disposed in the passageway. The fuel cell assembly includes a fuel cell stack having a plurality of fuel cells. The plurality of fuel cells extend from an inlet end in fluid communication with the diffusion chamber to an outlet end extending through the combustion liner and in fluid communication with the combustion chamber.

A thermal management system for an energy storage system for an aircraft includes a pump circulating a thermal management fluid through the thermal management system and an energy storage device of the aircraft. A controller circuitry may control a variable pumping capacity of the pump based on sensing pressure or temperature of the thermal management fluid at the energy storage device. The controller circuitry may default operation of the pump to a first pumping capacity in response to the pressure or temperature being within a predetermined operating range and a predetermined failure condition or a power demand of an aircraft engine supply bus exceeding a predetermined threshold. The controller controlling operation of the pump to a second pumping capacity in response to absence of the power demand signal of the aircraft engine supply bus and the pressure or temperature being within the predetermined operating range.

A turbine engine assembly includes a core engine that generates an exhaust gas flow, a condenser where water is extracted from the exhaust gas flow, an evaporator where heat is input into the water that is extracted by the condenser to generate a first steam flow, a first steam turbine where the first steam flow is expanded and cooled to generate a first cooled flow, a bypass passage that defines a path for the first steam flow around the first steam turbine, and a superheater where at least one of the first steam flow and the first cooled flow is reheated to generate a second steam flow.

A hybrid-electric propulsion system includes a propulsor, a turbomachine, and an electrical system having an electric machine coupled to the turbomachine. A method for operating the propulsion system includes operating, by one or more computing devices, the turbomachine to rotate the propulsor and generate thrust for the aircraft; receiving, by the one or more computing devices, data indicative of an un-commanded loss of the thrust generated from the turbomachine rotating the propulsor; and providing, by the one or more computing devices, electrical power to the electric machine to add power to the turbomachine, the propulsor, or both in response to receiving the data indicative of the un-commanded loss of thrust.

An engine system of an aircraft includes an energy storage system, a gas turbine engine, and a controller. The gas turbine engine includes a low spool, a high spool, a low-spool generator operably coupled to the low spool, and a high-spool electric motor operably coupled to the high spool. The controller is configured to detect a braking condition of the aircraft, transfer power from the low-spool generator to the energy storage system based on the storage capacity state of the energy storage system, and transfer power to the high spool through the high-spool electric motor to support combustion in the gas turbine engine while a rotational speed of the low spool is reduced responsive to the low-spool generator extracting energy from the low spool.

A power electronics converter may include: a converter commutation cell having a power circuit and a gate driver circuit, the power circuit including at least one power semiconductor switching element and at least one capacitor, wherein each power semiconductor switching element is embedded in a solid insulating material, wherein each power semiconductor switching element has at least three terminals including a gate terminal, wherein the gate driver circuit is electrically connected to and configured to provide switching signals to the gate terminal of each power semiconductor switching element, wherein a peak rated power output of the power electronics converter is greater than 25 KW, and wherein a total rated capacitance of the power circuit of the converter commutation cell divided by the peak rated power output of the power electronics converter is less than or equal to 5 nF/W.

A fuel pod for a hybrid electric aircraft. The fuel pod includes a housing, a fuel tank, a generator and a connection mechanism. The fuel tank is contained within the housing and is configured to hold a fuel therein. The generator is contained within the housing and is connected to the fuel tank. The generator is configured to power at least one of a plurality of flight components of a hybrid electric aircraft. The connection mechanism is at the housing and is configured to removably attach the fuel pod to the hybrid electric aircraft. The connection mechanism includes an electrical interface configured to electrically link to at least one of the plurality of flight components of the hybrid electric aircraft, and a communication interface configured to communicatively link to a flight controller communicatively connected to the hybrid electric aircraft.

A method of controlling a multi-engine aircraft includes receiving input for commanded thrust and modifying the commanded thrust using a model of an incumbent powerplant to generate a modified commanded thrust for matching aircraft performance with a new powerplant to the aircraft performance with the incumbent powerplant. The method includes applying the modified commanded thrust to the new powerplant.