The invention relates to the redundant supply of kinetic energy to a drive system of an aircraft in order to ensure in each case largely safe operation of the aircraft during normal operation of the system and also in various emergency scenarios. The system has two electrical machines (110, 130), each of which is connected to in each case one of the two propellers. A high-voltage battery (120) and an internal combustion engine (140) are also provided. These components of the system are, depending on the type of component, electrically and/or mechanically connected to one another and to the propellers, and a controller of the system controls energy flows between the components depending on the mode of operation or readiness for operation of the components in a redundant manner in such a way that the aircraft can be largely safely operated in various normal and emergency situations.

A power transmission gearbox provided with at least one lubrication system including a lubrication pump. The lubrication pump is in fluid flow communication with a fluid flow circuit leading to at least one spray means. The gearbox includes an emergency tank suitable for containing a lubrication fluid, the emergency tank being in fluid flow communication with the fluid flow circuit, the emergency tank being connected by at least one pipe to the fluid flow circuit upstream from each spray means, the lubrication fluid being moved in the fluid flow circuit to each spray means by a gas that is set into motion by the lubrication pump in the event of a leak of the lubrication liquid.

A vertical take-off and landing aircraft using a hybrid electric propulsion system includes an engine, a generator that produces electric power using power supplied by the engine, and a battery that stores the produced electric power. A motor receives the electric power stored in the battery and electric power produced by the generator but not stored in the battery and provides the power to a thrust generating apparatus. A controller selects either silence mode or normal mode, and determines the amount of electric power stored in the battery and the amount of electric power not stored in the battery from the electric power supplied to the motor. In the silence mode, the controller supplies only the electric power stored in the battery and controls a duration by adjusting output power of motor. In the normal mode, the controller supplies electric power not stored in the battery.

A method for controlling a converter, wherein positive and negative lines of an intermediate circuit are connected by a half-bridge to an alternating voltage phase conductor via semiconductor switches, where each semiconductor switch has a series connected separate fuse, and where the method includes detecting a defective semiconductor switch that permanently remains in an electrically conductive state and incrementally melting the fuse of the defective semiconductor switch by short-circuiting the positive and the negative lines to each other multiple times via the defective semiconductor switch and via at least two others of the semiconductor switches, during which each short circuit lasts only one pulse duration Tsoa that is shorter than a melting duration Ta needed by the fuse to melt in the event of a continuous short circuit such that the converter robustly reacts in the event of a permanent short circuit caused by one of the semiconductor switches.

A hybrid electric aircraft propulsion system at least includes a motor with induction effect to drive a propeller or propulsion fan. The motor is directly supplied from the electrical output of a generator. The generator is driven by a variable speed engine and as such the generator has a output frequency proportional to the speed of the engine. A controller is operatively coupled to the motor, the generator and the engine. The controller is operable to control a speed of the engine and the excitation of the generator to provide an output at a target voltage and frequency to drive the motor at a desired torque and speed.

An aircraft includes a fuselage extending between a forward end and an aft end. An aft engine is mounted to the aft end of the fuselage, the aft engine defining a centerline. The aft engine further includes a nacelle having a bottom section, the bottom section having a forward lip. The forward lip of the bottom section defines a camber line. The camber line, in turn, defines an angle relative to the centerline of the aft engine greater than or equal to at least about five degrees.

A vertical take-off and landing aircraft using a hybrid electric propulsion system includes an engine, a generator that produces electric power using power supplied by the engine, and a battery that stores the produced electric power. A motor receives the electric power stored in the battery and electric power produced by the generator but not stored in the battery and provides the power to a thrust generating apparatus. A controller selects either silence mode or normal mode, and determines the amount of electric power stored in the battery and the amount of electric power not stored in the battery from the electric power supplied to the motor. In the silence mode, the controller supplies only the electric power stored in the battery and controls a duration by adjusting output power of motor. In the normal mode, the controller supplies electric power not stored in the battery.

An aircraft includes a fuselage extending between a forward end and an aft end. The aircraft additionally includes a propulsor mounted to the fuselage at the aft end of the fuselage, the propulsor including an outer nacelle and the outer nacelle defining an inlet. Additionally, the aircraft includes a deployable assembly attached to at least one of the fuselage or the outer nacelle, the deployable assembly movable between a stowed position and an engaged position. The deployable assembly alters an airflow towards the propulsor or into the propulsor through the inlet defined by the outer nacelle when in the engaged position to increase an efficiency of the aft fan and/or of the aircraft.

A gas turbine engine includes a compressor section and a turbine section together defining a core air flowpath. The rotary component is rotatable with the compressor section and the turbine section. The gas turbine engine additionally includes an electric machine rotatable with the rotary component and positioned coaxially with the rotary component at least partially inward of the core air flowpath. The electric machine is flexibly mounted to a static frame member, or flexibly coupled to the rotary component, or both, such that the electric machine is mechanically isolated or insulated from various internal and external forces on the gas turbine engine.

A propulsion system includes an electric propulsor and a gas turbine engine. The propulsion system also includes an electric machine coupled to a rotary component of the gas turbine engine generating a voltage at a baseline voltage magnitude during operation of the gas turbine engine. An electric communication bus is provided electrically connecting the electric machine to the electric propulsor. The propulsion system additionally includes a means for providing a differential voltage to the electric propulsor equal to about twice the baseline voltage magnitude.