A method is provided for operating an aircraft system. During this operating method, a plurality of drive units are provided that include a thermal engine drive unit and an electric machine drive unit. A mechanical load is powered using a first of the drive units. The first of the drive units includes a first rotating structure. A parameter of the first rotating structure is monitored. A failure of the first of the drive units is detected based on the monitored parameter. A switch is made from the first of the drive units to a second of the drive units to power the mechanical load where the failure of the first of the drive units is detected.

A hybrid-electric or all-electric powertrain may include a power control unit electrically coupled to an energy storage system. The power control unit may determine a power level command based at least in part on a power level request for the powertrain, and a power level-UCL and/or a power level-LCL. The power level-UCL and/or the power level-LCL may be based at least in part on an aggregate obverse power level request representing a requested power level for one or more obverse powertrains electrically coupled to the energy storage system. The power level commands may be limited by the power level-UCL and/or the power level-LCL. The power level-UCL may be set equal to either an available discharge power capacity or an apportionate discharge power capacity. The power level-LCL may be set equal to either an available storage power capacity or an apportionate storage power capacity.

An after-fan system for an engine may comprise an after-fan turbine an electrical generator operationally coupled to the after-fan turbine, and an electric motor electrically coupled to the electrical generator. The electrical generator may be configured to generate an electrical current in response to rotation of the after-fan turbine. The electric motor may be configured to generate torque.

In an aircraft that flies utilizing power generated by an engine or power charged in a battery, a temperature control system includes a battery that stores power for starting the engine and flying, a temperature adjusting apparatus for warming or cooling the battery by each of at least the power charged in the battery and power feeding from an external power source, and a control section for detecting presence or absence of the power feeding, and if the power feeding is present, controlling the apparatus to warm or cool the battery using the power feeding, and if the power feeding is absent, controlling the apparatus to warm or cool the battery using charged power of the battery. Even if the power feeding has been lost, it is possible to maintain a temperature and a state of charge of the battery enabling the engine to start and fly.

A hybrid electric propulsion (HEP) system can include a heat engine torque sensor connected between a heat engine and a combining gear box to sense a heat motor input torque input to the combining gear box, an electric motor torque sensor connected between an electric motor and the combining gear box to sense an electric motor input torque input to the combining gear box, and a combining gear box torque sensor connected to an output of the combining gearbox. The system can include a HEP controller operatively connected to each of the heat engine torque sensor, the electric motor torque sensor, and the combining gear box torque sensor to receive one or more torque signals therefrom. The controller can be configured to output one or more output signals as a function of the signals from each of the heat engine torque sensor, the electric motor torque sensor, and the combining gear box torque sensor.

A battery charging system for a hybrid electric powerplant can be configured to determine a maximum available charging power available from windmilling and/or excess thermal engine power available, and to use up to the maximum available charging power and/or the excess thermal engine power available to charge a battery. In certain embodiments, a control module can be configured to determine the maximum available charging power available from windmilling.

The present disclosure pertains to electric machines such as electric propulsion systems for aircraft that integrated cooling systems, and methods of cooling such an electric machine. Exemplary electric machines include an electric motor that has a stator, a rotor, and a drive shaft operably coupled to the rotor. Exemplary electric machines further include a motor cooling conduit that defines a pathway for conveying a cooling fluid through or around at least a portion of the electric motor, a casing assembly that circumferentially surrounds at least a portion of the electric motor, a casing assembly conduit integrally formed within at least a portion of the casing assembly which defines a pathway for conveying the cooling fluid through the at least a portion of the casing assembly, and a pump or compressor operably coupled to the drive shaft and configured to circulate the cooling fluid through the motor cooling conduit and the casing assembly conduit.

An aircraft having a vertical takeoff and landing flight mode and a forward flight mode. The aircraft includes a fuselage and an X-tiltwing that is rotatable relative to the fuselage between a vertical lift orientation and a forward thrust orientation. The X-tiltwing has oppositely disposed V-wing members each having first and second wing sections. In the vertical lift orientation, the first and second wing sections of each V-wing member are generally in the same horizontal plane. In the forward thrust orientation, the first and second wing sections of each V-wing member are generally in the same vertical plane. A distributed propulsion system is attached to the X-tiltwing such that a plurality of propulsion assemblies is attached to each wing section. A flight control system is operably associated with the distributed propulsion system to independently control each of the propulsion assemblies.

A method for limiting torque on a rotorcraft. The rotorcraft comprises an installation having a rotor, the installation including at least three motors driving a power transmission gearbox, the MGB including a rotor mast for moving the rotor. The method comprises a step of determining a engine torque limit for each of at least the three motors, each engine torque limit being established by a control computer of the aircraft by taking into consideration the distribution among the at least three motors of the total power (Ptot) delivered by the at least three motors for enabling the rotorcraft to operate.

A propulsion system for an aircraft includes at least two gas turbine engines and at least one auxiliary propulsion fan. The at least one auxiliary propulsion fan is configured to selectively receive a motive force from either or both of the at least two gas turbine engines through at least one shaft operatively coupled to the at least one auxiliary propulsion fan.