Abstract: An assembly includes a housing, a carrier, a spring element and a seal element. The housing includes a bore and an annular groove that extends axially along a centerline into the housing from the bore. The carrier projects axially along the centerline into the annular groove. The carrier is configured to translate axially along the centerline relative to the housing. The spring element is arranged within the annular groove. The spring element is configured to bias the carrier axially away from the housing along the centerline. The seal element is mounted to the carrier and arranged within the bore.

Abstract: An exemplary gas turbine engine assembly includes a first spool having a first turbine operatively mounted to a first turbine shaft, and a second spool having a second turbine operatively mounted to a second turbine shaft. The first and second turbines are mounted for rotation about a common rotational axis within an engine static structure. The first and second turbine shafts are coaxial with one another. First and second towershafts are respectively coupled to the first and second turbine shafts. An accessory drive gearbox has a set of gears. A compressor is driven by the first towershaft. The engine assembly further includes a starter generator assembly, and a transmission coupling the starter generator assembly to the first set of gears.

Abstract: A seal housing may comprise an aft flange, an outer diameter (OD) ring and a stopper. The stopper may extend radially inward from a radially inner surface of OD ring. The stopper may be configured to interface with a monobloc carbon seal. The stopper may comprise a circumferential stopping portion and an axial stopping portion. There may be a plurality of the stopper.

Abstract: A gas turbine engine comprises a low speed spool and a high speed spool, with each of the spools including a turbine to drive a respective one of the spools. The high speed spool rotates at a higher speed than the low speed spool. A high speed power takeoff is driven to rotate by the high speed spool, and a low speed power takeoff is driven to rotate by the low speed spool. The high speed power takeoff drives a starter generator and a permanent magnet alternator. The low speed power takeoff drives a variable frequency generator.

Abstract: A gas turbine engine assembly includes a turbine section having first and second turbines mounted for rotation about a common rotational axis within an engine static structure, first and second turbine shafts coaxial with one another and to which the first and second turbines are respectively operatively mounted, first and second towershafts respectively coupled to the first and second turbine shafts, an accessory drive gearbox mounted to the engine static structure, a hydraulic pump, and a transmission. The transmission is transitionable between a first mode where the hydraulic pump is driven at a first speed relative to a first towershaft, a second mode where the hydraulic pump is driven at a different, second speed relative to the first towershaft, and a third mode where the hydraulic pump is driven at a different, third speed relative to the first towershaft.

Abstract: A gas turbine engine assembly includes a turbine section having first and second turbines mounted for rotation about a common rotational axis within an engine static structure, first and second turbine shafts coaxial with one another and to which the first and second turbines are respectively operatively mounted, first and second towershafts respectively coupled to the first and second turbine shafts, an accessory drive gearbox mounted to the engine static structure, and a transmission transitionable between a first mode where an electric machine is driven at a first speed relative to the first towershaft, and a second mode where the electric machine is driven at a different, second speed relative to the first towershaft.

Abstract: A gas turbine engine comprises a high speed spool and a low speed spool. A low speed power takeoff is driven by the low speed spool and a high speed power takeoff is driven by the high speed spool. The low speed power takeoff drives a plurality of low speed driven accessories about low speed spool drive axes and the high speed power takeoff drives a plurality of high speed driven accessories about high speed spool drive axes. The low speed spool drive axes are generally tangential to an envelope defined about a center axis of the engine, and the high speed spool drive axes are generally tangential to an envelope defined about the center.

Abstract: An assembly is provided for a gas turbine engine with an axial centerline. This assembly includes a gearbox, a first torque transmission apparatus and a second torque transmission apparatus. The gearbox includes a plurality of first gears and a plurality of second gears. The first gears are meshed together and respectively rotatable about parallel first gear axes. The second gears are meshed together and respectively rotatable about parallel second gear axes. Each of the first gear axes and each of the second gear axes is non-parallel with the axial centerline. The first torque transmission apparatus is configured to drive the first gears. The second torque transmission apparatus is configured to drive the second gears.

Abstract: A gas turbine engine comprises a low speed spool and a high speed spool, with each of the spools including a turbine to drive a respective one of the spools. The high speed spool rotates at a higher speed than the low speed spool. A high speed power takeoff is driven to rotate by the high speed spool, and a low speed power takeoff is driven to rotate by the low speed spool. The high speed power takeoff drives a starter generator and a permanent magnet alternator. The low speed power takeoff drives a variable frequency generator.

Abstract: An exemplary gas turbine engine assembly includes a transmission coupling a starter generator assembly to a first set of gears. The transmission is transitionable between a first mode where the starter generator assembly is driven at a first speed relative to the second towershaft, and a second mode where the starter generator assembly is driven at a different, second speed relative to the second towershaft.

Abstract: A gas turbine engine comprises a low speed spool and a high speed spool, with each of the spools including a turbine to drive a respective one of the spools. The high speed spool rotates at a higher speed than the low speed spool. A high speed power takeoff is driven to rotate by the high speed spool, and a low speed power takeoff is driven to rotate by the low speed spool. The high speed power takeoff drives a starter generator and a permanent magnet alternator. The low speed power takeoff drives a variable frequency generator.

Abstract: Aspects of the disclosure are directed to a rotatable shaft, and a plurality of bearings coupled to the rotatable shaft, where the plurality of bearings include a first bearing, a second bearing, and a third bearing, where the first bearing defines an axial first bearing centerline, where the second bearing defines an axial second bearing centerline, where the third bearing defines an axial third bearing centerline, and where the axial second bearing centerline is radially offset from the axial first bearing centerline and the axial third bearing centerline.

Abstract: A gas turbine engine comprises a high speed spool and a low speed spool. A low speed power takeoff is driven by the low speed spool and a high speed power takeoff is driven by the high speed spool. The low speed power takeoff drives a plurality of low speed driven accessories about low speed spool drive axes and the high speed power takeoff drives a plurality of high speed driven accessories about high speed spool drive axes. The low speed spool drive axes are generally tangential to an envelope defined about a center axis of the engine, and the high speed spool drive axes are generally tangential to an envelope defined about the center.

Abstract: An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.

Abstract: An assembly is provided for a gas turbine engine with an axial centerline. This assembly includes a gearbox, a first torque transmission apparatus and a second torque transmission apparatus. The gearbox includes a plurality of first gears and a plurality of second gears. The first gears are meshed together and respectively rotatable about parallel first gear axes. The second gears are meshed together and respectively rotatable about parallel second gear axes. Each of the first gear axes and each of the second gear axes is non-parallel with the axial centerline. The first torque transmission apparatus is configured to drive the first gears. The second torque transmission apparatus is configured to drive the second gears.

Abstract: A gas turbine engine comprises a low speed spool and a high speed spool, with each of the spools including a turbine to drive a respective one of the spools. The high speed spool rotates at a higher speed than the low speed spool. A high speed power takeoff is driven to rotate by the high speed spool, and a low speed power takeoff is driven to rotate by the low speed spool. The high speed power takeoff drives a starter generator and a permanent magnet alternator. The low speed power takeoff drives a variable frequency generator.

Abstract: A gas turbine engine includes a turbine section configured to rotate about an engine axis relative to an engine static structure. A fan section is configured to rotate about the engine axis relative to the engine static structure. A geared architecture operatively connects the fan section to the turbine section. The geared architecture includes an input gear and an output gear both configured to rotate about the engine axis. A set of idler gears are arranged radially outward relative to and operatively coupling with the input and output gears.

Abstract: A gearbox assembly includes a housing structure, a shear bracket that connects the housing structure to a hanger to hold the housing structure relative to a turbomachine, and a thermal spray layer between the shear bracket and the housing structure.

Abstract: An exemplary gas turbine engine assembly includes a transmission coupling a starter generator assembly to a first set of gears. The transmission is transitionable between a first mode where the starter generator assembly is driven at a first speed relative to the second towershaft, and a second mode where the starter generator assembly is driven at a different, second speed relative to the second towershaft.

Abstract: An exemplary gas turbine engine assembly includes a first spool having a first turbine operatively mounted to a first turbine shaft, and a second spool having a second turbine operatively mounted to a second turbine shaft. The first and second turbines are mounted for rotation about a common rotational axis within an engine static structure. The first and second turbine shafts are coaxial with one another. First and second towershafts are respectively coupled to the first and second turbine shafts. An accessory drive gearbox has a set of gears. A compressor is driven by the first towershaft. The engine assembly further includes a starter generator assembly, and a transmission coupling the starter generator assembly to the first set of gears.