A motoring system for a gas turbine engine having: a reduction gear train having an input and an output; an electric motor operably connected to the input; a clutch operably connected to the output, the clutch in operation engages and disengages the reduction gear train; and a mechanical shaft fuse operably connecting the output to the clutch, the mechanical shaft fuse in operation shears when torque on the mechanical shaft fuse is greater than or equal to a selected value. The mechanical shaft fuse includes a plurality of through holes.

A turbomachine dual spool transmission system can include a transmission assembly configured to connect to a combination output of a dual spool differential at a transmission input to be driven by the combination output to turn a transmission output. The transmission assembly can be configured to provide a first output gear ratio in a first state and a second output gear ratio in a second state. The system can include the dual spool differential. The dual spool differential can include a gear assembly configured to combine a low pressure spool input and a high pressure spool input into a combination output to provide an output speed range smaller than a low pressure speed range alone.

A method for controlling noise emitted by a hybrid-electric gas turbine engine for an aircraft during a takeoff flight condition includes applying a first total rotational force to a shaft with a turbine and an electric motor. The first total rotational force includes a first electric rotational force applied by the electric motor and a first thermal rotational force applied by the turbine. The first total rotational force has a first rotational force ratio of the first electric rotational force to the first thermal rotational force. The method further includes controlling the noise emitted by the gas turbine engine by reducing the first rotational force ratio from an initial rotational force ratio of the rotational force ratio as an altitude of the aircraft increases and maintaining the first total rotational force substantially constant while reducing the rotational force ratio.

A gas turbine engine including a first rotor assembly comprising a first drive shaft extended along a longitudinal direction; a housing coupled to the first rotor assembly to provide rotation of the first rotor assembly around an axial centerline; a first accessory assembly, wherein the first accessory assembly sends and/or extracts energy to and from the first rotor assembly; and a first clutch assembly disposed between the first rotor assembly and the first accessory assembly. The first clutch assembly engages and disengages the first rotor assembly to and from the first accessory assembly.

In an embodiment, a gas turbine system is provided. The gas turbine system may include a supplementary air system and a flow diffuser configured to receive compressed air from the supplementary air system. The gas turbine system further comprises a gas turbine compressor downstream the flow diffuser, a combustor downstream the gas turbine compressor, a turbine downstream the combustor, and a turbine haft. The turbine shaft comprises a thrust bearing and a clutch. When the gas turbine system is operating, the gas turbine compressor does not consume electricity.

A gas turbine engine (10) includes a compressor section, a turbine section, and an accessory gearbox (100). A turning unit (200) for the gas turbine engine includes an output assembly (204) configured to be mechanically coupled to the gas turbine engine, and an electric motor (202). The electric motor is operable to rotate, through the output assembly, one or more components of the compressor section or the turbine section at a rotational speed less than about fifty revolutions per minute during a shut-down condition of the gas turbine engine.

An example system for providing mechanical power to an aircraft accessory with a turbine engine, where the turbine engine includes a low-speed spool and a high-speed spool, includes an accessory gearbox disposed between the low-speed spool and the high-speed spool and a clutch disposed within or external to the accessory gearbox. The accessory gearbox is configured to drive the aircraft accessory, and the clutch is configured to enable either the high-speed spool or the low-speed spool to provide mechanical power to the aircraft accessory via the accessory gearbox.

A gas turbine engine is provided. The gas turbine engine includes a turbomachine having a low speed spool and a high speed spool; a rotor assembly coupled to the low speed spool; an electric machine rotatable with the low speed spool for extracting power from the low speed spool, for adding power to the low speed spool, or both; and an inter-spool clutch positioned between the low speed spool and the high speed spool for selectively coupling the low speed spool to the high speed spool.

A multi-engine system for an aircraft, has: a first engine having a first output shaft, a first core shaft, and a first electric machine drivingly engaged by the first output shaft or the first core shaft; a second engine having a second output shaft, a second core shaft, and a second electric machine drivingly engaged to the second core shaft; a reduction gearbox drivingly engaged by the first output shaft and by the second output shaft for driving a common load; and a transmission path between the first engine and the second engine, the transmission path being independent from the reduction gearbox and being one or more of: a torque-transfer connection between the second core shaft and the first core shaft or the first output shaft via a coupling gearbox, and an electrical connection between the generator and the electric motor to transmit electrical power to the electric motor.

A single drive, dual clutch accessory drive system for an aircraft including an input shaft connected to a low pressure spool of a turbine engine. The input shaft is rotatable at a first input speed and at a second input speed that is distinct from the first input speed. An output shaft is operatively connected to an aircraft accessory. A first drive path operatively connects the input shaft and the output shaft. The first drive path includes a first clutch and a gear system. The first drive path is operable to adjust the first input speed to a selected output shaft speed. A second drive path operatively connects the input shaft and the output shaft. The second drive path includes a second clutch. The second drive path is operable to rotate the output shaft at the second input speed.