Abstract: An impeller shroud assembly for a gas turbine engine includes an annular impeller shroud disposed about an axial centerline. The impeller shroud includes a shroud inducer portion and a shroud exducer portion disposed radially outward of the shroud inducer portion and extending to an outer radial end of the impeller shroud. The shroud inducer portion and the shroud exducer portion defining an impeller-facing surface of the impeller shroud. The impeller shroud has a pivot point defined between the shroud inducer portion and the shroud exducer portion. The impeller shroud assembly further includes a clearance control device connected to the shroud exducer portion of the impeller shroud proximate the outer radial end. The clearance control device is configured to pivot the shroud exducer portion of the impeller shroud about the pivot point between a first axial position and a second axial position.

Abstract: An impeller shroud assembly for a gas turbine engine includes an annular impeller shroud disposed about an axial centerline. The impeller shroud includes a shroud inducer portion and a shroud exducer portion disposed radially outward of the shroud inducer portion and extending to an outer radial end of the impeller shroud. The shroud inducer portion and the shroud exducer portion defining an impeller-facing surface of the impeller shroud. The impeller shroud has a pivot point defined between the shroud inducer portion and the shroud exducer portion. The impeller shroud assembly further includes a clearance control device connected to the shroud exducer portion of the impeller shroud proximate the outer radial end. The clearance control device is configured to pivot the shroud exducer portion of the impeller shroud about the pivot point between a first axial position and a second axial position.

Abstract: The gas turbine engine for an aircraft includes at least a low pressure spool with a low pressure turbine shaft operatively connected to at least one turbine, the low pressure turbine shaft rotatable about an engine axis, and a low pressure compressor operatively connected to a low pressure compressor shaft that is independently rotatable relative to the low pressure turbine shaft. A differential gearbox has an input operatively connected to the low pressure turbine shaft, a first output and a second output, the first output of the differential gearbox operatively connected to the low pressure compressor shaft and the second output of the differential gearbox operatively connected to an output shaft of the gas turbine engine. The differential gearbox permits the output shaft, the low pressure compressor shaft and the low pressure turbine shaft to rotate at different speeds.

Abstract: The aircraft can have a first engine secured to a first wing on a first side of a fuselage, and a second engine secured to a second wing on a second side of the fuselage, the second wing having a proximal end secured to the fuselage, and a distal end extending away from the fuselage. While operating the first engine, compressed gas can be conveyed from the first engine to a thrust generating device located at the distal end of the second wing.

Abstract: An auxiliary power unit (APU) includes, in serial flow communication: an engine compressor, a combustor and a turbine, the turbine rotatable about an engine axis. A first shaft operatively connects the turbine to the engine compressor and extends non-parallel to the engine axis. A second shaft operatively connects the turbine to a load and extends non-parallel to the engine axis. A method of operating an APU is also described.

Abstract: The gas turbine engine includes a combustion section including an annular swirl combustor having a combustor inlet, and a compressor section including a centrifugal compressor with an impeller, the impeller compressing and swirling an airflow and discharging the compressed and swirled airflow from the impeller outlet into the combustor inlet. The turbine section includes a radial turbine having a turbine fuel inlet and a turbine fuel outlet, the radial turbine receiving a flow of fuel at the turbine fuel inlet and discharging the flow of fuel from the turbine fuel outlet of the radial turbine into the combustor inlet.

Abstract: Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. In one embodiment, such system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid-driven fluid propeller configured to drive the bleed air through the heat exchanger.

Abstract: The aircraft can have a first engine secured to a first wing on a first side of a fuselage, and a second engine secured to a second wing on a second side of the fuselage, the second wing having a proximal end secured to the fuselage, and a distal end extending away from the fuselage. While operating the first engine, compressed gas can be conveyed from the first engine to a thrust generating device located at the distal end of the second wing.

Abstract: Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. The system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid propeller configured to drive the bleed air through the heat exchanger. The fluid propeller is disposed downstream of the heat exchanger.

Abstract: The gas turbine engine for an aircraft includes at least a low pressure spool with a low pressure turbine shaft operatively connected to at least one turbine, the low pressure turbine shaft rotatable about an engine axis, and a low pressure compressor operatively connected to a low pressure compressor shaft that is independently rotatable relative to the low pressure turbine shaft. A differential gearbox has an input operatively connected to the low pressure turbine shaft, a first output and a second output, the first output of the differential gearbox operatively connected to the low pressure compressor shaft and the second output of the differential gearbox operatively connected to an output shaft of the gas turbine engine. The differential gearbox permits the output shaft, the low pressure compressor shaft and the low pressure turbine shaft to rotate at different speeds.

Abstract: The gas turbine engine includes a combustion section including an annular swirl combustor having a combustor inlet, and a compressor section including a centrifugal compressor with an impeller, the impeller compressing and swirling an airflow and discharging the compressed and swirled airflow from the impeller outlet into the combustor inlet. The turbine section includes a radial turbine having a turbine fuel inlet and a turbine fuel outlet, the radial turbine receiving a flow of fuel at the turbine fuel inlet and discharging the flow of fuel from the turbine fuel outlet of the radial turbine into the combustor inlet.

Abstract: A system for controlling gas turbine engine rotor blades tip clearance is described. A rotor is mounted to an engine shaft, supported by a thrust bearing, for rotation within a gas path shroud circumscribing blades of the rotor, the gas path shroud having a non-cylindrical shape in the vicinity of the rotor blades. A rotary actuator is associated with the thrust bearing and configured for axial translation of the thrust bearing, to thereby axially translate the engine shaft and the rotor blades relative to the gas path shroud. This translation is configured to vary the blade tip clearance of the rotor.

Abstract: Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. In one embodiment, such system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid-driven fluid propeller configured to drive the bleed air through the heat exchanger.

Abstract: Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. The system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid propeller configured to drive the bleed air through the heat exchanger. The fluid propeller is disposed downstream of the heat exchanger.

Abstract: An auxiliary power unit (APU) includes, in serial flow communication: an engine compressor, a combustor and a turbine, the turbine rotatable about an engine axis. A first shaft operatively connects the turbine to the engine compressor and extends non-parallel to the engine axis. A second shaft operatively connects the turbine to a load and extends non-parallel to the engine axis. A method of operating an APU is also described.

Abstract: A gas turbine engine system includes, in serial flow communication, an engine compressor configured to compress air, a combustor in which the compressed air is mixed with fuel and ignited to generate a stream of combustion gases, and a turbine configured to extract energy from the combustion gases. An electric generator is configured to be driven by the turbine and generate electric energy during use. An electric motor is configured to be driven by electric energy generated by the electric generator. The electric motor is configured in use to drive the engine compressor.

Abstract: A system for controlling gas turbine engine rotor blades tip clearance is described. A rotor is mounted to an engine shaft, supported by a thrust bearing, for rotation within a gas path shroud circumscribing blades of the rotor, the gas path shroud having a non-cylindrical shape in the vicinity of the rotor blades. A rotary actuator is associated with the thrust bearing and configured for axial translation of the thrust bearing, to thereby axially translate the engine shaft and the rotor blades relative to the gas path shroud. This translation is configured to vary the blade tip clearance of the rotor.

Abstract: The aircraft engine can have a core gas path extending sequentially across a core compressor, a core combustor, and a core turbine; a boost gas path extending from an intake to the core compressor, across a boost compressor, a bypass gas path extending from the intake to the core compressor, and a bypass valve operable to selectively open and close the bypass gas path. The intake flow can be directed either across the boost gas path for increased power output, or be directed to bypass the boost gas path via the bypass gas path.

Abstract: The aircraft engine can have a core gas path having a first combustor, a second gas path parallel to the core gas path, the second gas path having a second combustor, a turbine driven by the second gas path, a gearbox driven by the turbine, and a valve configured for selectively opening and closing the second gas path.

Abstract: The aircraft engine can have a core gas path extending from an intake across a core compressor, and then manifolding to a plurality turbine intake paths, each turbine intake path leading to a respective turbine unit via a respective combustor unit, and gearing drivingly connecting the collective rotary power of the turbine units to at least one power output shaft. During operation, the different core-turbine units can be operated simultaneously and efficiently, or one or more of the core-turbine units can be selectively shut down while the other core-turbine units continue to operate efficiently to lower the power output.