Abstract: A hybrid electric propulsion system including: a gas turbine engine comprising a low speed spool and a high speed spool, the low speed spool comprising a low pressure compressor and a low pressure turbine, and the high speed spool comprising a high pressure compressor and a high pressure turbine; an electric motor configured to augment rotational power of the high speed spool or the low speed spool; and a controller to: detect an in-flight windmill re-start condition of the gas turbine engine; and cause power to be supplied from a power source to the electric motor in order to augment rotational power of the high speed or the low speed spool during the detected in-flight windmill re-start condition.

Abstract: A gas turbine engine according to an example of the present disclosure may include, among other things, a fan section including a fan having a plurality of fan blades and including an outer housing surrounding the fan blades to establish a bypass duct, a geared architecture, a first spool including a first shaft that interconnects a first compressor and a fan drive turbine, the fan drive turbine driving the fan through the geared architecture. The gas turbine engine is rated to provide an amount of thrust at ground idle, and the gas turbine engine is rated to provide an amount of thrust at maximum takeoff. A thrust ratio is defined as a ratio of the amount of thrust at ground idle divided by the amount of thrust at maximum takeoff. The thrust ratio can be less than or equal to 0.050.

Abstract: A gas turbine engine includes a low-pressure spool, a high-pressure spool, and an electric motor. The low-pressure spool includes a low-pressure compressor in rotational communication with a low-pressure turbine and a fan via a first shaft. The high-pressure spool includes a high-pressure compressor in rotational communication with a high-pressure turbine via a second shaft. The electric motor is operably connected to the second shaft. The electric motor is configured to apply a rotational force to the second shaft.

Abstract: A turbine engine includes integrated electric machines in the compressor section and the turbine section to supplement power produced from fuel with electric power. The example compressor section includes a compressor electric motor that is coupled to a compressor generator. The example turbine section includes a turbine electric motor that is coupled to the geared architecture to supplement power driving the fan section. A turbine generator provides electric power to the turbine electric motor.

Abstract: A system includes a gas turbine engine of an aircraft, the gas turbine engine having a low speed spool, a high speed spool, and a combustor. The system also includes a low spool motor configured to augment rotational power of the low speed spool and a high spool motor configured to augment rotational power of the high speed spool. The system further includes a controller configured to cause fuel flow. The controller is configured to control a thrust response of the gas turbine engine to a thrust target between zero and a thrust level to move the aircraft during engine start and during engine idle. The controller is also configured to control the low spool motor to drive rotation of the low speed spool responsive to a thrust command while the controller does not command fuel flow to the combustor.

Abstract: Examples described herein provide a computer-implemented method that includes controlling a high spool motor of an aircraft to cause the high spool motor to drive rotation of a high speed spool of a gas turbine engine of the aircraft to maintain a desired compressor pressure and a desired flow within a combustor of the gas turbine engine. The method further includes commanding fuel flow to the combustor responsive to a trigger event to cause the gas turbine engine to start to a fuel-burning mode.

Abstract: A turbine engine includes integrated electric machines in the compressor section and the turbine section to supplement power produced from fuel with electric power. The example compressor section includes a compressor electric motor that is coupled to a compressor generator. The example turbine section includes a turbine electric motor that is coupled to the geared architecture to supplement power driving the fan section. A turbine generator provides electric power to the turbine electric motor.

Abstract: A gas turbine engine according to an example of the present disclosure may include, among other things, a fan section including a fan having a plurality of fan blades and including an outer housing surrounding the fan blades to establish a bypass duct, a geared architecture, a first spool including a first shaft that interconnects a first compressor and a fan drive turbine, the fan drive turbine driving the fan through the geared architecture. The gas turbine engine is rated to provide an amount of thrust at ground idle, and the gas turbine engine is rated to provide an amount of thrust at maximum takeoff. A thrust ratio is defined as a ratio of the amount of thrust at ground idle divided by the amount of thrust at maximum takeoff. The thrust ratio can be less than or equal to 0.050.

Abstract: A hybrid electric propulsion system includes a gas turbine engine having a low speed spool and a high speed spool. The low speed spool includes a low pressure compressor and a low pressure turbine, and the high speed spool includes a high pressure compressor and a high pressure turbine. The hybrid electric propulsion system also includes an energy storage system, an electric motor configured to augment rotational power of the high speed spool, and a controller. The controller is operable to detect a start condition of the gas turbine engine, control power delivery from the energy storage system to the electric motor based on detecting the start condition, and provide a compressor stall margin using a power-assist provided by the electric motor to the high speed spool over a targeted speed range during starting of the gas turbine engine.

Abstract: A system includes a gas turbine engine having a low speed spool, a high speed spool, and a combustor. The system also includes a low spool motor configured to augment rotational power of the low speed spool. The system further includes a controller configured to cause fuel flow. The controller is operable to control the low spool motor to drive rotation of the low speed spool responsive to a thrust command while the controller does not command fuel flow to the combustor.

Abstract: A surge control system includes a rotor system with at least one compressor section and at least one turbine section operably coupled to a shaft. The surge control system also includes sensors configured to collect sensor data from the rotor system, an electric motor operably coupled to the rotor system, and a controller. The controller is operable to detect surge event from the sensor data, determine an amount of power to apply to the rotor system, and increase the amount of power provided to the rotor system to recover from the surge event.

Abstract: A system includes a gas turbine engine having a low speed spool and a high speed spool. The system also includes a spool coupling system configured to mechanically link the low speed spool and the high speed spool. A controller is operable to determine a mode of operation of the gas turbine engine, monitor for a spool coupling activation condition associated with the mode of operation, and activate the spool coupling system based on the controller detecting the spool coupling activation condition. Engagement and power transfer between the low speed spool and the high speed spool occurs based on activation of the spool coupling system and reaching an engagement condition of the spool coupling system.

Abstract: A surge control system includes a rotor system with at least one compressor section and at least one turbine section operably coupled to a shaft. The surge control system also includes sensors configured to collect sensor data from the rotor system, an electric motor operably coupled to the rotor system, and a controller. The controller is operable to detect surge event from the sensor data, determine an amount of power to apply to the rotor system, and increase the amount of power provided to the rotor system to recover from the surge event.

Abstract: A turbine engine includes integrated electric machines in the compressor section and the turbine section to supplement power produced from fuel with electric power. The compressor section includes a compressor electric motor that is electrically coupled to a compressor generator. The example turbine section includes a turbine electric motor that is coupled to a geared architecture to supplement power driving the fan section. A turbine generator driven by a portion of the turbine section provides electric power to the turbine electric motor.

Abstract: A turbine engine includes integrated electric machines in the compressor section and the turbine section to supplement power produced from fuel with electric power. The example compressor section includes a compressor electric motor that is coupled to a compressor generator. The example turbine section includes a turbine electric motor that is coupled to the geared architecture to supplement power driving the fan section. A turbine generator provides electric power to the turbine electric motor.

Abstract: A gas turbine engine includes a low-pressure spool, a high-pressure spool, and an electric motor. The low-pressure spool includes a low-pressure compressor in rotational communication with a low-pressure turbine and a fan via a first shaft. The high-pressure spool includes a high-pressure compressor in rotational communication with a high-pressure turbine via a second shaft. The electric motor is operably connected to the second shaft. The electric motor is configured to apply a rotational force to the second shaft.

Abstract: A gas turbine engine includes a low-pressure spool, a high-pressure spool, and an electric motor. The low-pressure spool includes a low-pressure compressor in rotational communication with a low-pressure turbine and a fan via a first shaft. The high-pressure spool includes a high-pressure compressor in rotational communication with a high-pressure turbine via a second shaft. The electric motor is operably connected to the second shaft. The electric motor is configured to apply a rotational force to the second shaft.

Abstract: A turbine engine includes integrated electric machines in the compressor section and the turbine section to supplement power produced from fuel with electric power. The example compressor section includes a compressor electric motor that is coupled to a compressor generator. The example turbine section includes a turbine electric motor that is coupled to the geared architecture to supplement power driving the fan section. A turbine generator provides electric power to the turbine electric motor.

Abstract: A surge control system includes a rotor system with at least one compressor section and at least one turbine section operably coupled to a shaft. The surge control system also includes sensors configured to collect sensor data from the rotor system, an electric motor operably coupled to the rotor system, and a controller. The controller is operable to detect surge event from the sensor data, determine an amount of power to apply to the rotor system, and increase the amount of power provided to the rotor system to recover from the surge event.

Abstract: A gas turbine engine includes a low-pressure spool, a high-pressure spool, and an electric motor. The low-pressure spool includes a low-pressure compressor in rotational communication with a low-pressure turbine and a fan via a first shaft. The high-pressure spool includes a high-pressure compressor in rotational communication with a high-pressure turbine via a second shaft. The electric motor is operably connected to the second shaft. The electric motor is configured to apply a rotational force to the second shaft.