An impeller is configured to be rotated by a flowing fluid. A fluid stator includes a fixed ring parallel to a plane of rotation of the impeller. The fixed ring has a center in-line with a center of rotation of the impeller. A rotatable ring is rotatable relative to, and parallel to, the fixed ring. The rotatable ring has a center in-line with a center of rotation of the impeller. Stator vanes extend between the fixed ring and the rotatable ring. The stator vanes define an inlet cross sectional area upstream of the impeller. The cross sectional area is dependent upon a relative position of the fixed ring and the rotatable ring. An actuator is configured to rotate the rotatable ring. An electric rotor is coupled to, and configured to rotate in unison with, the impeller. An electric stator encircles the electric rotor. The electric stator includes coil windings.

Subsonic turbofan engines with variable outer guide vanes (OGVs) and associated methods. A subsonic turbofan engine includes an engine core configured to generate a torque, a fan configured to accelerate an air flow, an engine nacelle, and a plurality of OGVs positioned downstream of the fan. Each OGV is configured to transition among a plurality of OGV configurations defined between and including a nominal configuration and a reduced-drag configuration. The subsonic turbofan engine is configured to operate only at subsonic speeds. In examples, methods of operating a subsonic turbofan engine include transitioning each of a plurality of OGVs from a nominal configuration to a reduced-drag configuration. Transitioning each OGV from the nominal configuration to the reduced-drag configuration is performed while the subsonic engine operates at subsonic speeds.

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.

A gas turbine engine (10) comprising: a high pressure turbine (17); a low pressure turbine (19); a high pressure compressor (15) coupled to the high pressure turbine (17) by a high pressure shaft (27); a propulsor (23) and a low pressure compressor (14) coupled to the low pressure turbine (19) via a low pressure shaft (26) and a reduction gearbox (30); wherein the low pressure compressor (14) consists of four compressor stages (14) and defines a cruise pressure ratio of between 2.4:1 and 3.3:1; the high pressure compressor (15) defines a cruise pressure ratio of less than 17:1; and the high pressure compressor (15) and low pressure compressor (14) together define a cruise core overall pressure ratio of greater than 36:1.

An oil system for a gas turbine engine includes an oil pump driven by a gear train having a main input drive gear rotating when a propulsor rotor rotates. The gear train includes two sets of gears joined by two connection shafts each having a clutch. The first set of the gears include a forward input gear and a reverse input gear each driven by the main input drive gear. The forward and the reverse input gears drive a pinion gear in the second set of gears through a clutch. Each clutch transmits rotation driven in a same driving direction and slips in an alternate driving direction. The first set of the gears has an even number of the gears, and the second set of the gears has an odd number of the gears.

A gas turbine engine includes a main compressor section with a downstream most location. A turbine section has a high pressure turbine. A tap line is connected to tap air from a location upstream of the downstream most location in the main compressor section. The tapped air is connected to a heat exchanger and then to a cooling compressor. The cooling compressor compresses air downstream of the heat exchanger, and is connected to deliver air into the high pressure turbine. A bypass valve is positioned downstream of the main compressor section, and upstream of the heat exchanger. The bypass valve selectively delivers air directly to the cooling compressor without passing through the heat exchanger under certain conditions.

A reduction gearbox which has: an input, which can be coupled to an input shaft, which has an input speed; an output, which rotates at an output speed that is lower than the input speed; and at least one statically arranged component. It is envisaged that an electric generator is integrated into the reduction gearbox, said generator comprising a rotor and a stator, wherein the rotor of the electric generator is coupled to the output of the reduction gearbox, and the stator of the electric generator is coupled to a statically arranged component of the reduction 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.

The present invention relates to a shaft for a propulsion system configured to rotate a reducing mechanism about a rotational axis, the shaft comprising: —a first end configured to engage with an input gear of the reducing mechanism, —a first bellows and a second bellows, the first bellows and the second bellows being rotationally symmetrical about the rotational axis, the first bellows extending between the first end and the second bellows, and —a frustoconical body mechanically connecting the first bellows and the second bellows.

An assembly for mounting an auxiliary component to an engine case of a gas turbine includes a support bracket, the support bracket having a first end configured for attachment to a first flange of the engine case, a second end configured for attachment to a second flange of the engine case, and an intermediate portion located intermediate the first end and the second end; a bearing member disposed within the intermediate portion; and a mechanical fuse disposed within the bearing member.