A bowed rotor prevention system for a gas turbine engine of an aircraft is provided. The bowed rotor prevention system includes a gear train and a bowed rotor prevention motor operable to drive rotation of a starting spool of the gas turbine engine through the gear train at a substantially constant speed upon engine shutdown until an energy storage source is depleted.

A bowed rotor prevention system for a gas turbine engine of an aircraft is provided. The bowed rotor prevention system includes a gear train and a bowed rotor prevention motor operable to drive rotation of a starting spool of the gas turbine engine through the gear train at a substantially constant speed upon engine shutdown until an energy storage source is depleted.

An engine starting system for a gas turbine engine is provided. The engine starting system comprising: a gas turbine engine including rotational components comprising an engine compressor, an engine turbine, and a rotor shaft operably connecting the engine turbine to the engine compressor, wherein each rotational component is configured to rotate when any one of the rotational components is rotated; a variable frequency generator operably connected to at least one of the rotational components, the variable frequency generator being configured to rotate the rotational components; and a motor controller in electronic communication with the variable frequency generator, the motor controller being configured to command the variable frequency generator to rotate the rotational components at a selected angular velocity for a selected period of time.

An engine starting system for a gas turbine engine is provided. The engine starting system comprising: a gas turbine engine including rotational components comprising an engine compressor, an engine turbine, and a rotor shaft operably connecting the engine turbine to the engine compressor, wherein each rotational component is configured to rotate when any one of the rotational components is rotated; a permanent magnet alternator operably connected to at least one of the rotational components, the permanent magnet alternator being configured to rotate the rotational components; and a motor controller in electronic communication with the permanent magnet alternator, the motor controller being configured to command the permanent magnet alternator to rotate the rotational components at a selected angular velocity for a selected period of time.

An electric machine and a turning gear system for aircraft gas turbine engines are provided. The system has an electric machine designed for dual mode operation and a controller. The stator winding arrangement in the electric machine enables operation in either generating mode, during normal flight or motoring mode, during active engine turning. The controller is configured to reconfiguration connections of the windings external to the electric machine.

An apparatus, system, and method for reducing the warpage of a rotor of an aircraft engine. When the aircraft engine is placed in standby mode, a solenoid-operated bypass valve may receive a control signal to open. When open, the solenoid-operated bypass valve places an electric hydraulic pump in fluidic communication with an engine driven hydraulic pump. The engine driven hydraulic pump rotates because of the pressured provided by the electrical hydraulic pump. The mechanical linkage between the engine driven hydraulic pump and the rotor causes the rotor of the aircraft engine to rotate.

A hybrid gas-electric turbine engine for turboprop or turboshaft applications is disclosed together with associated methods. In various embodiments disclosed herein, the turbine engine comprises a turbine configured to be driven by a flow of combustion gas; a turbine shaft configured to be driven by the turbine and transfer power to a load coupled to the turbine engine and an electric motor configured to transfer power to the load coupled to the turbine engine. The rotor may have a rotor axis of rotation that is radially offset from a shaft axis of rotation of the turbine shaft. In some embodiments, the electric motor may be a multi-rotor electric motor.

To provide an aircraft engine in which an accessory can be directly supported with no accessory gearbox intervening to thereby suppress an increase in size thereof, the aircraft engine (E) includes a take-out shaft (11) having a first end portion, connected with an engine rotary shaft (9) and extending in a radially outward direction, and also having a second end portion connected with an accessory (1), and a mounting pad (12) provided in an engine main body (EB) and to which the accessory (1) is fitted. The mounting pad (12) forms an outer perimeter of an opening (48) through which the take-out shaft (11) extends. The opening (48) is sealed by a covering (47), through which the take-out shaft (1) extends, and a sealing member (49) to seal between the covering (47) and the take-out shaft (11).

To provide an aircraft engine in which an accessory can be directly supported with no accessory gearbox intervening to thereby suppress an increase in size thereof, the aircraft engine (E) includes a take-out shaft (11) having a first end portion, connected with an engine rotary shaft (9) and extending in a radially outward direction, and also having a second end portion connected with an accessory (1), and a mounting pad (12) provided in an engine main body (EB) and to which the accessory (1) is fitted. The mounting pad (12) forms an outer perimeter of an opening (48) through which the take-out shaft (11) extends. The opening (48) is sealed by a covering (47), through which the take-out shaft (1) extends, and a sealing member (49) to seal between the covering (47) and the take-out shaft (11).

A turbofan engine includes a first spool including a first turbine and a second spool including a second turbine. A superposition gear system includes a plurality of intermediate gears engaged to a sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. A second tower shaft is engaged to drive the sun gear. A starter is selectively coupled to the sun gear through a starter clutch. A first electric motor and a second electric motor are coupled to the superposition gear system and are operable to input power into a corresponding one of the first and second spools.