The present disclosure relates to a fuel cell system and an aircraft equipped with a fuel cell system. The aircraft may have a fuselage elongated in a front-rear direction, a front horizontal stabilizer towards a front of the fuselage, main wings extending to opposite sides of the fuselage, a rear horizontal stabilizer towards a rear of the fuselage, the fuel cell system rear to the main wings and a controller. The fuel cell system may be configured to provide electrical energy for driving a motor on each of the main wings. The controller may be configured to cause transmission of electrical energy from the fuel cell system to the motor. A center of gravity of the aircraft may be near front edges of the main wings. A flow rate of air into the fuel cell system may be controlled in response to an outside air condition.

An aircraft and a method for controlling such an aircraft comprising two turboshaft engines, an electric machine, an electrical power source and a rotor rotated by one of the two turboshaft engines and/or by the electric machine. The aircraft comprises at least one controller configured to implement, at all times, a current operating mode of the electric machine and the electrical power source, selected from seven operating modes, allowing standard start-up or fast start-up respectively of a turboshaft engine in a switched-off state or in a standby state. The electric machine can also provide first or second levels of power assistance to a turboshaft engine in order to transmit engine torque to the gas generator of that turboshaft engine, apply mechanical resistance to a turboshaft engine or help ventilate a turboshaft engine in a switched-off state.

A propulsion assembly includes a first torque source coupled with a first shaft and a second torque source coupled with a second shaft. A coupler selectively couples the first and second torque sources. When the first and second torque sources are coupled via the coupler, in response to a command to decouple the first torque source, an unloading operation is performed to decrease the torque output provided by the first torque source to a threshold, and when reached, the first shaft is decoupled from the coupler. When the first torque source is coupled with the coupler but the second torque source is not, in response to a command to couple the second torque source, a speed matching operation is performed to increase the speed of the second shaft to match a speed of the first shaft, and when the speeds are matched, the second shaft is coupled to the coupler.

Disclosed is a vertical take-off and landing aerodyne, including a fuselage, two wings, horizontal flight propulsion unit and at least one pair of rotors intended to provide propulsion and lift in the take-off and landing phases. The rotors are retractable and the horizontal flight propulsion unit includes a counter-rotating propeller, situated at the tail of the aerodyne, and a drive unit for rotating the counter-rotating propeller, the counter-rotating propeller being capable of being oriented by a control unit about two axes, one parallel to the yaw axis and the other parallel to the pitch axis of the aerodyne, such that the counter-rotating propeller is used for controlling the attitude of the aerodyne, the latter therefore not having a tail unit.

A method for operating an electric fan of an aircraft propulsion system includes driving a plurality of fan blades of the electric fan with an electric machine to generate thrust for the aircraft; and driving the electric machine with the plurality of fan blades of the electric fan to generate electrical power subsequent to driving the plurality of fan blades of the electric fan with the electric machine to generate thrust for the aircraft.

There is provided a hybrid electric aircraft propulsion system and method for operating same. The method comprises providing, to a first electric motor and a second electric motor, alternating current (AC) electric power from a generator, the generator receiving rotational power from a thermal engine, providing, to the first electric motor and the second electric motor, AC electric power from at least one motor inverter, the at least one motor inverter configured to convert DC electric power from a DC power source into AC electric power, and selectively driving the first and second electric motors from the generator, the at least one motor inverter, or a combination thereof, wherein the first electric motor drives a first rotating propulsor and the second electric motor drives a second rotating propulsor.

An aircraft comprising a hybrid electric aircraft propulsion system. The system comprises a first sub-assembly having a first electric propulsor assembly and a first thermal propulsor assembly, the first thermal propulsor assembly having a first thermal engine, a first generator and a first rotating propulsor, the first electric propulsor assembly attached to the aircraft at a first location and the first thermal propulsor assembly attached to the aircraft at a second location. The system also comprises a second sub-assembly having a second electric propulsor assembly and a second thermal propulsor assembly, the second thermal propulsor assembly having a second thermal engine, a second generator and a second rotating propulsor, the second electric propulsor assembly attached to the aircraft at a third location and the second thermal propulsor assembly attached to the aircraft at a fourth location.

Methods and systems for operating a hybrid electric aircraft propulsion system mounted to an aircraft. The method comprises driving a first rotating propulsor from a first electric motor operatively connected to a generator, driving a second rotating propulsor from a second electric motor operatively connected to the generator, and driving a third rotating propulsor from a thermal engine, the thermal engine operatively connected to the generator and configured to drive the generator.

Methods and systems for operating a hybrid electric aircraft propulsion system. The method comprises providing alternating current (AC) electric power to a first electric motor to drive a first rotating propulsor, providing the first electric motor with AC electric power from at least one motor inverter operatively coupled to a direct current (DC) power source, detecting a failure in a path to the first electric motor, and selectively rearranging a first switching arrangement between the generator, the at least one motor inverter, and the first electric motor.

There is described a method and system for operating a hybrid electric aircraft propulsion system. The method comprises modulating AC electric power applied to a first electric propulsor or a second electric propulsor from at least one motor inverter to synchronize the frequency of the first electric propulsor or the second electric propulsor with the frequency of a generator.