There are described methods and systems for operating an aircraft turboprop engine. The method comprises controlling a propeller of the turboprop engine based on a selected one of a reference propeller rotational speed and a minimum propeller blade angle while the turboprop engine is running; detecting an inflight restart of the turboprop engine; and controlling the propeller during the inflight restart in accordance with at least one of a modified reference propeller rotational speed and a modified minimum propeller blade angle to maintain an actual propeller blade angle above an aerodynamic disking angle during the inflight restart.

A method and a system for providing in-flight reverse thrust for an aircraft are provided. The aircraft comprises an engine having a rotor, a compressor mechanically coupled to the rotor, and a variable geometry mechanism provided upstream of the compressor and configured to modulate an amount of compression work performed by the compressor. The method comprises operating the rotor with the variable geometry mechanism in a first position, receiving a request to increase reverse thrust for the rotor, in response to the request, adjusting the variable geometry mechanism from the first position towards a second position, the variable geometry mechanism having a greater opening angle in the second position than in the first position, and operating the rotor with the variable geometry mechanism in the second position for causing an increase in the amount of compression work performed by the compressor and an increase in reverse thrust for the rotor.

There are provided a gas turbine system and a gas turbine power generator that can achieve an increase in output power and a decrease in fuel efficiency together and curb an increase in cost and weight. There is also provided a gas turbine system that can stably supply a necessary amount of air to a combustor even when a compressor and a turbine on one side are stopped. The gas turbine system 1 includes a plurality of gas turbine units 2 and 3, a single combustor 4, a plurality of pipes 5, a plurality of on-off valves 6, and a control unit 7. In a first operation mode, the control unit 7 controls switching-on/off of the on-off valves 6 such that air is supplied to the combustor 4 from a first compressor 21 and a second compressor 31. In a second operation mode, the control unit 7 controls switching-on/off of the on-off valves 6 such that air compressed in stages while sequentially passing through the first compressor 21 and the second compressor 31 is supplied to the combustor 4, and supplies air to turbines such that they can be expanded in stages.

A vehicle provided with a power plant having at least one heat engine, the vehicle having an air-conditioning system comprising a fluid circulating in a fluid circulation system, the fluid circulation system comprising at least one pump configured to cause the fluid to circulate in a fluid circuit. The vehicle comprises one injection member per heat engine configured to inject the fluid into the associated heat engine, the vehicle comprising a back-up circuit fluidly connecting the fluid circulation system to each injection member, the back-up circuit comprising a distribution device controlled by a controller to authorize, on command, circulation of the fluid towards an injection member.

A tiltrotor aircraft having a propulsion configuration that divorces the engine core power from the thrust fan, using a combined gearbox with a plurality of clutches to couple and decouple one or more rotor systems and one or more thrust fans. The aircraft can be operable for vertical takeoff and landing (VTOL) in a helicopter mode, forward flight in a proprotor mode, and high-speed forward flight in an airplane (jet) mode. The propulsion configuration provides shaft horsepower (SHP) to rotors for VTOL flight, while also providing SHP to the thrust fan for high speed flight. Allowing the rotor and the thrust fan to be clutched on and off, sequentially, enables transition from rotor-borne VTOL flight to wing-borne thrust fan flight, and back.

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 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. One of the electric motor and the electric generator is disposed axially between the outlet and the AGB and the other of the electric motor and the electric generator is disposed axially between the inlet and the RGB.

An electric power system for a vehicle includes at least one electric machine, one or more power rectifiers, and a plurality of DC channels. The at least one electric machine includes a plurality of tooth-wound multi-phase windings that are substantially magnetically decoupled, and the at least one electric machine is mechanically balanced even if one of the plurality of windings is de-energized. The one or more power rectifiers are configured to produce rectified power from the power generated by the at least one electric machine. The plurality of DC channels are formed after the at least one power rectifier and are configured to provide DC power to one or more loads within a vehicle.

In one aspect, there is provided a planetary gearbox, comprising a sun gear, a plurality of planet gear assemblies, each planet gear assembly having a main gear meshed with the sun gear, a fore lateral gear and an aft lateral gear disposed on opposite sides of the main gear and rotating therewith, a diameter of the main gear being different than a diameter of the fore and aft lateral gears, a planet carrier rotatably supporting at least some of the planet gear assemblies, and at least one fore ring gear meshed with the fore lateral gears, at least one aft ring gear meshed with the aft lateral gears, wherein one of the sun gear, the planet carrier, and the ring gears is configured to be operatively connected to an input, one is configured to be operatively connected to an output, and rotation of a remaining one is limited.

A tiltrotor aircraft having a propulsion configuration that divorces the engine core power from the thrust fan, using a combined gearbox with a plurality of clutches to couple and decouple one or more rotor systems and one or more thrust fans. The aircraft can be operable for vertical takeoff and landing (VTOL) in a helicopter mode, forward flight in a proprotor mode, and high-speed forward flight in an airplane (jet) mode. The propulsion configuration provides shaft horsepower (SHP) to rotors for VTOL flight, while also providing SHP to the thrust fan for high speed flight. Allowing the rotor and the thrust fan to be clutched on and off, sequentially, enables transition from rotor-borne VTOL flight to wing-borne thrust fan flight, and back.