A method of optimizing the noise generated by a hybrid power plant of a rotorcraft in flight, the hybrid power plant driving a main rotor of the rotorcraft in rotation and being provided with at least one engine, with at least one electric machine, and with at least one electrical energy source that electrically powers the electric machine. The method includes a determination step for determining a required power delivered by the hybrid power plant and that is required for the flight phase, and a distribution step for distributing the required power between the at least one engine and the electric machine as a function of a target noise level and of the required power for the flight phase, as well as of a model for the noise generated by the at least one engine as a function of one of its parameters.

A hybrid electric propulsion system for an aircraft is provided that includes a thermal engine, an electric motor, a gearbox, an electric power storage unit, a propulsion unit, and a controller. The thermal engine has a main oil pump configured to be driven by the thermal engine. The gearbox is in communication with the thermal and electric motors. The propulsion unit includes a propeller having propeller blades, and a pitch change mechanism. The controller is in communication with the thermal and electric motors, the propulsion unit, and a memory storing instructions. The instructions when executed cause the controller to control the electric motor to operate using electrical power from the electric power storage unit to cause the main oil pump to actuate and produce a flow of engine oil to the pitch change mechanism for a period of time sufficient to feather the propeller blades.

A method of and system for damping vibrations in a hybrid-electric propulsion system configured to drive a propulsor is provided. The hybrid-electric propulsion system includes a thermal engine, an electric motor, and an inverter. The method includes: a) controlling the thermal engine and the electric motor to operate at a target propulsion parameter, wherein the inverter is used in the controlling of the electric motor; b) determining a presence of a vibrational response within the hybrid-electric propulsion system; c) producing a vibration compensation signal configured to damp the vibrational response within the hybrid-electric propulsion system; and d) controlling the electric motor to damp the vibrational response using the vibrational compensation signal.

A drive mechanism for use with an electric motor and a clutch mechanism The drive mechanism comprises a rotor shaft, a disconnect shaft, a disconnect mechanism, at least one damper element, a part of the clutch, and a lubrication system. The rotor shaft and disconnect shaft have a longitudinal axis A. The disconnect shaft transmits torque between the rotor shaft and the clutch mechanism. The disconnect shaft comprises the part of the clutch and a shaft element. The disconnect mechanism is configured to move the disconnect shaft between an engaged position in which the part of the clutch is engaged with the clutch mechanism and a disengaged position in which the part of the clutch is not engaged with the clutch mechanism. The at least one damper element is configured to absorb at least part of any kinetic energy introduced into the disconnect shaft.

A drive mechanism for use with an electric motor and a clutch mechanism The drive mechanism comprises a rotor shaft, a disconnect shaft, a disconnect mechanism, at least one damper element, a part of the clutch, and a lubrication system. The rotor shaft and disconnect shaft have a longitudinal axis A. The disconnect shaft transmits torque between the rotor shaft and the clutch mechanism. The disconnect shaft comprises the part of the clutch and a shaft element. The disconnect mechanism is configured to move the disconnect shaft between an engaged position in which the part of the clutch is engaged with the clutch mechanism and a disengaged position in which the part of the clutch is not engaged with the clutch mechanism. The at least one damper element is configured to absorb at least part of any kinetic energy introduced into the disconnect shaft.

An aircraft propulsion system includes a hybrid-electric power plant for delivering power to an air mover for propelling an aircraft. The hybrid-electric power plant includes a heat engine operatively connected to a first air mover, and an electric motor operatively connected to a second air mover. The second air mover is positioned on a wing of the aircraft outboard from the heat engine. A method for reducing trailing vortices includes powering a first air mover of an aircraft with a heat engine during a take-off stage, a climb stage, a cruise-stage and/or a descent stage. The method includes powering a second air mover of the aircraft with an electrical motor during the take-off stage and/or the climb stage. The method includes freewheeling the second air mover during the cruise stage and/or the descent stage to generate mechanical energy and reduce wing tip vortices.

An aircraft propulsion system includes a hybrid-electric power plant for delivering power to an air mover for propelling an aircraft. The hybrid-electric power plant includes a heat engine operatively connected to a first air mover, and an electric motor operatively connected to a second air mover. The second air mover is positioned on a wing of the aircraft outboard from the heat engine. A method for reducing trailing vortices includes powering a first air mover of an aircraft with a heat engine during a take-off stage, a climb stage, a cruise-stage and/or a descent stage. The method includes powering a second air mover of the aircraft with an electrical motor during the take-off stage and/or the climb stage. The method includes freewheeling the second air mover during the cruise stage and/or the descent stage to generate mechanical energy and reduce wing tip vortices.

A propulsion system is provided for an aircraft. This propulsion system includes a propulsor rotor, a drivetrain, a first power unit and a second power unit. The drivetrain is coupled to the propulsor rotor. The first power unit includes a first overrunning clutch and a first electric motor. The first overrunning clutch is configured to selectively couple the first electric motor to the drivetrain. The first electric motor is configured to drive rotation of the propulsor rotor through the first overrunning clutch and the drivetrain. The second power unit includes a second overrunning clutch and a second electric motor. The second overrunning clutch is configured to selectively couple the second electric motor to the drivetrain. The second electric motor is configured to drive the rotation of the propulsor rotor through the second overrunning clutch and the drivetrain.

An aircraft includes an aircraft heat source; a propulsion system including an electric propulsion engine, the electric propulsion engine including an electric motor and a fan rotatable by the electric motor, the electric propulsion engine further defining a fan air flowpath; a thermal management system including a heat source exchanger in thermal communication with the aircraft heat source, a heat sink exchanger in thermal communication with the fan air flowpath of the electric propulsion engine, and a thermal distribution bus extending from the heat source exchanger to the heat sink exchanger; and a control system operably connected to the thermal management system for selectively thermally coupling the heat sink exchanger with the heat source exchanger.

An aircraft includes an aircraft heat source; a propulsion system including an electric propulsion engine, the electric propulsion engine including an electric motor and a fan rotatable by the electric motor, the electric propulsion engine further defining a fan air flowpath; a thermal management system including a heat source exchanger in thermal communication with the aircraft heat source, a heat sink exchanger in thermal communication with the fan air flowpath of the electric propulsion engine, and a thermal distribution bus extending from the heat source exchanger to the heat sink exchanger; and a control system operably connected to the thermal management system for selectively thermally coupling the heat sink exchanger with the heat source exchanger.