Abstract: An operating method is provided during which a command is received to decrease thrust generated by a propulsor rotor from a first thrust level to a second thrust level. The propulsor rotor is operatively coupled to an engine core and an electric machine. The engine core includes a flowpath, a compressor section, a combustor section and a turbine section. The engine core is operated in a transient state to decrease total power of the engine core from a first power level to a second power level in response to the command. The electric machine is operated as a generator to reduce power output from the engine core to the propulsor rotor while the engine core is operating in the transient state. A clearance control system for the engine core is operated based on the operation of the electric machine.

Abstract: A method is provided for an HEP system that includes a gas turbine engine and an electric motor configured to assist the gas turbine engine by rotating a first shaft of the gas turbine engine. The method includes receiving a throttle command, and determining, based on an amount of electric power available to the electric motor, a power allocation between the gas turbine engine and the electric motor for an acceleration period during which a rotational speed of the first shaft is accelerated to implement the throttle command. The method also includes determining a target clearance between a tip of a rotor blade and a case structure for the acceleration period and, during the acceleration period, implementing the power allocation and operating an active clearance control (ACC) system to establish the target clearance. A system for an aircraft and a method for a HEP system are also disclosed.

Abstract: An operating method is provided during which a command is received to increase thrust generated by a propulsor rotor from a first thrust level to a second thrust level. The propulsor rotor is operatively coupled to an engine core and an electric machine. The engine core includes a flowpath, a compressor section, a combustor section and a turbine section. The engine core is operated in a transient state to increase power output from the engine core to the propulsor rotor from a first power level to a second power level in response to the command. The electric machine is operated to boost the power output from the engine core to the propulsor rotor while the engine core is operating in the transient state. A clearance control system for the engine core is operated based on the operation of the electric machine.

Abstract: An operating method is provided during which a command is received to decrease thrust generated by a propulsor rotor from a first thrust level to a second thrust level. The propulsor rotor is operatively coupled to an engine core and an electric machine. The engine core includes a flowpath, a compressor section, a combustor section and a turbine section. The engine core is operated in a transient state to decrease total power of the engine core from a first power level to a second power level in response to the command. The electric machine is operated as a generator to reduce power output from the engine core to the propulsor rotor while the engine core is operating in the transient state. A clearance control system for the engine core is operated based on the operation of the electric machine.

Abstract: A gas turbine engine according to an example of the present disclosure may include, among other things, a propulsor section including a propulsor having a plurality of propulsor blades, a geared architecture, a first spool including a first shaft that interconnects a first compressor and a first turbine, the first driving the propulsor 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 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: Hybrid electric propulsion systems are described. The systems include a gas turbine engine having low and high speed spools, each spool having a respective compressor and turbine. A mechanical power transmission is configured to at least one of extract power from and supply power to at least one of the low speed spool and the high speed spool, an electric machine is configured to augment rotational power of at least one of the spools, and a controller is operable to determine a rotational speed of the low speed spool, determine a rotational speed of the high speed spool, determine if a predetermined operational zone of operation based on the determined rotational speeds is present, and when a predetermined operational zone is determined, control a power augmentation of at least one spool to limit dwell operation of the gas turbine engine within the predetermined operational zone.

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 according to an example of the present disclosure may include, among other things, a propulsor section including a propulsor having a plurality of propulsor blades, a geared architecture, a first spool including a first shaft that interconnects a first compressor and a first turbine, the first driving the propulsor 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 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 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.