Abstract: A power transmission arrangement comprises a first power transmission member connectable to a first main shaft of an engine. The arrangement also includes a second power transmission member connectable to a second main shaft of the engine and to a third power transmission member. A coupling assembly is provided which has a selectable coupling condition to couple the first power transmission member to the second power transmission member to allow power to be transmitted from the third power transmission member to the first main shaft of the engine via the first power transmission member. The coupling assembly has a decoupling condition to decouple the first power transmission member from the second power transmission member to allow power to be transmitted from the main shaft of the engine to the third power transmission member via the second power transmission member.

Abstract: A gas feed assembly (30) comprises a compressor arrangement (32) comprising first and second compressor (34, 36). The gas feed assembly includes outlet means (42) for gas for the first and second compressors (34, 36). The gas feed assembly includes a first inlet (38) for the first compressor (34) and a second inlet (40) for the second compressor (36). The gas feed assembly further includes a valve assembly (52, 64) for allowing gas to enter either, or both, of the first and second compressors from at least one gas source.

Abstract: A generator assembly for a gas turbine engine. The assembly includes an electrical generator connected via a first sprag clutch to an accessory gearbox driven by the engine. The generator is also connected by a second sprag clutch to an air turbine connected to engine bleed valves which are selectively open when the engine speed falls below a predetermined level. The clutches are arranged such that the generator is driven at any time by the fastest rotating of the gearbox and turbine.

Abstract: A drive arrangement for driving, or for being driven by, a fluid is disclosed. The drive arrangement comprises a rotatable member (40) for receiving the fluid, and having mounted thereon a plurality of drive members (56). The drive members (56) are movable between a drive position, in which the drive members can drive, or be driven by, the fluid, and a non-drive position in which the drive members (56) are substantially prevented from driving or being driven by a fluid received in the rotatable member (40).

Abstract: A cooling system for a gas turbine engine (FIG. 1) comprises a pre-swirl arrangement, preferably including a pre-swirl chamber, for providing cooling air to a turbine blade disc, and a ventilation arrangement for providing ventilation air to a rotating component of the gas turbine engine. The cooling system includes an air bypass arrangement, which preferably includes first, second and third air bypass duct portions, for conveying ventilation air away from the pre-swirl arrangement.

Abstract: A nacelle assembly 40 adapted for mounting on a ducted fan gas turbine engine 20 comprising a generally annular body 46 having an air inlet 42 and an air outlet 44, the generally annular body 46 encircling a region of the engine 20 when working in operative association with the engine 20 and has a first attachment means 48 to a rigid member 58 and a second attachment means 52 to a casing assembly 34 on the engine 20 wherein the second attachment means 52 is frangible.

Abstract: A seal is provided in which a weir pool is created by overlapping a flange and a weir edge flange. A passage is provided whereby through controlled lubricant leakage a carbon seal is effectively cooled to prevent overheating of a portion adjacent that carbon seal during operation. The weir pool is created by centrifugal forces and the remainder of the lubricant passes over the weir edge in order to lubricate bearings. Thus, the seal allows use of a carbon seal between shafts. Furthermore, at least one shaft can be more conveniently formed integral with a turbine blade assembly.

Abstract: A seal is provided in which a weir pool is created by overlapping a flange and a weir edge flange. A passage is provided whereby through controlled lubricant leakage a carbon seal is effectively cooled to prevent overheating of a portion adjacent that carbon seal during operation. The weir pool is created by centrifugal forces and the remainder of the lubricant passes over the weir edge in order to lubricate bearings. Thus, the seal allows use of a carbon seal between shafts. Furthermore, at least one shaft can be more conveniently formed integral with a turbine blade assembly.