A reverse-flow gas turbine engine includes a core of the gas turbine engine comprising multiple spools rotatable about a center axis of the gas turbine engine. Each spool is configured to pressurize air and to extract energy from combustion gases. The air and combustion gases are configured to flow through the core in a forward direction from an air inlet at an aft end of the core to an outlet at a forward end of the core. A propeller is disposed forward of the outlet. A reduction gearbox (RGB) is drivingly engaged to the core. An electric motor is drivingly engaged to the propeller and disposed axially between the RGB and the propeller.

A fan module for an aircraft turbomachine includes a fan with a disc carrying fan blades and a rotor of an electric machine. The rotor has an annular shape and is mounted coaxially downstream of the fan. The module further includes an annular support for the rotor with a downstream end fixed to the rotor and with an upstream end fixed to the fan disc. The support is fixed to the disc by shear bolts configured to break when a torque transmitted by the disc to the support exceeds a predetermined threshold.

An aircraft propulsion system includes a hydrocarbon fuel store, a hydrogen fuel store, an engine system capable of producing thrust by combusting hydrocarbon fuel and/or combusting or oxidising hydrogen fuel, a conveying system to convey hydrocarbon and hydrogen fuel from the fuel stores to the engine system and a control system to control the respective flow rates of the fuel within the conveying system. The control system adapts the fractions of the total fuel energy flow rate to the engine system represented by the hydrocarbon and hydrogen fuel energy flow rates in order to reduce climate warming impact caused by at least one of carbon dioxide, water vapour and condensation trails and/or increase climate cooling impact caused by condensation trails produced by the aircraft propulsion system compared to a dual-fuel propulsion system in which a reserve of hydrocarbon fuel is entirely combusted before any of a reserve of hydrogen fuel.

A method of making an impeller includes building the impeller in a layer by layer process in a build direction along the rotational axis starting from a base of the hub. The plurality of blades includes a plurality of perforated blades that support the shroud during additively manufacturing the impeller. The method can include installing the impeller in a fuel pump, air compressor, or the like, without removing the perforated blades from the impeller.

A method of making an impeller includes building the impeller in a layer by layer process in a build direction along the rotational axis starting from a base of the hub. The plurality of blades includes a plurality of perforated blades that support the shroud during additively manufacturing the impeller. The method can include installing the impeller in a fuel pump, air compressor, or the like, without removing the perforated blades from the impeller.

A propulsion system for an aircraft having an aft end is provided herein. The propulsion system can include an electric propulsion engine defining a central axis. The electric propulsion engine can include an electric motor, a fan rotatable about the central axis of the electric propulsion engine by the electric motor, a bearing supporting rotation of the fan, and a thermal management system. The thermal management system can include a lubrication oil circulation assembly for providing the bearing with lubrication oil. The lubrication oil circulation assembly can be driven independently of a shaft of the electric propulsion engine.

A propulsion system for an aircraft having an aft end is provided herein. The propulsion system can include an electric propulsion engine defining a central axis. The electric propulsion engine can include an electric motor, a fan rotatable about the central axis of the electric propulsion engine by the electric motor, a bearing supporting rotation of the fan, and a thermal management system. The thermal management system can include a lubrication oil circulation assembly for providing the bearing with lubrication oil. The lubrication oil circulation assembly can be driven independently of a shaft of the electric propulsion engine.

A through-flow gas turbine engine includes a core comprising multiple spools rotatable about a center axis. An accessory gearbox (AGB) is drivingly engaged to the core and disposed aft of the outlet. A reduction gearbox (RGB) is drivingly engaged to the core and disposed forward of the inlet. The RGB has an RGB output to provide rotational output to a rotatable load. An electric motor is drivingly engaged to the rotatable load. An electric generator is configured to provide electrical power to the electric motor. the electric motor and the electric generator are disposed axially adjacent one another, and axially between the outlet and the AGB.

An electrical system for connecting a rotary electric machine to dc networks operating at different voltages, the electric machine having polyphase winding sets each having a respective index. The electrical system has a first set of ac-dc converter circuits connected in a modular multilevel configuration, each ac-dc converter circuit having a respective index and an ac interface for connection with a corresponding winding set, and in which the modular multilevel configuration has dc outputs each having a respective index. The electrical system also has a set of dc-dc converter circuits each having a respective index and being configured to convert dc power between a voltage at a first dc interface and a voltage at a second dc interface, where a first dc interface of the nth dc-dc converter circuit is connected with the dc outputs of the modular multilevel configuration.

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.