Abstract: A gas turbine engine of the type comprising a first compressor 4, a second compressor 6, a combustor 8 and turbines 10 for driving the compressors 4 and 6 is provided with an air intake 16, leading to the second compressor 6. The flow from the first compressor 4 is discharged through vectorable nozzles 12,14. The nozzles 12,14 are movable between a first position where they discharge to ambient and a second position where they register with the intake 16 and the flow from the first compressor 4 discharges to the second compressor 6.

Abstract: A mechanism for use in linear friction welding has a drive-shaft (10) rotatable about a first longitudinal axis (12). An eccentric portion (10A) for locating a cam member (18) has a second longitudinal axis (16) spaced a distance d from the longitudinal axis (12) of the drive-shaft (10). The cam member (18) has a third longitudinal axis (20) spaced distance d from the second axis (16) of the cam member (18). A connecting-rod (24) is located via a big-end bearing (26) on the periphery of the cam member (18). When the drive-shaft is rotated with the third axis (20) of the cam member (18) displaced from the longitudinal axis (12) the connecting-rod reciprocates. If the cam member (18) is rotated about the second axis (16) of the eccentric portion (10A) until the longitudinal axis (12) and the third axis (20) of the cam member (18) are coincident the connecting-rod stops reciprocating.

Abstract: A load transference structure between a core engine and power turbine comprises a plurality of circumferentially spaced apart radially extending spoke members, each of which is attached at its radially inner extent to first and second axially spaced apart support panels. Each of the spoke members is provided with a circumferentially extending portion positioned adjacent the panels which are adapted to cooperate with a circumferentially adjacent spoke member in such a manner that radial but not circumferential load transfer is permitted to take place between them. The load transfer structure permits load transfer to take place between the core engine casing and the power turbine.

Abstract: A turbine rotor 14 of a gas turbine engine is provided with a mechanism 25 designed to tilt into the path of the turbine rotor blades to decelerate the rotor if a shaft 24, which connects the turbine rotor 14 to a compressor rotor 12 breaks. The mechanism 25 comprises a segmented stator vane assembly 26 in which the segments are supported at an upstream region of their radial inner ends on a deflectable strut 44 and by means of a tie 46 at a downstream region of their radial inner ends. When the shaft 24 breaks, the rearward movement of the rotor 14 is used to unlatch the strut 44 causing the NGV segments 26 to collapse inwards and tilt forwards into the path of the turbine rotor blades to decelerate the rotor. The NGV segments 26 and the turbine rotor blades destroy each other and the resulting debris is ejected out of the jet pipe 22 destroying further downstream turbine stages.

Abstract: A fan drive system comprising a main drive shaft 13 which drives the fan through a frangible coupling 27 and an auxilliary drive shaft 30 which by-passes the coupling 27. The auxilliary shaft 30 is pre-twisted elastically in the opposite direction to the direction of rotation of the main shaft 13, and is held in the pre-twisted state by the coupling 27. When the coupling 27 disconnects the drive from the main shaft 13, for example when the fan becomes unbalanced and transverse loads exceed a predetermined magnitude, the auxilliary shaft 30 unwinds. Unwinding of the shaft 30 cushions the fan against suddenly applied loads when the coupling 27 breaks and also reduces the loads on the coupling 27 during normal balanced running.

Abstract: A stator assembly for a turbomachine having a sealing plate which co-operates with sealing members on an adjacent rotor assembly to form air seals. The sealing plate is provided with a thermal slugging mass, the thermal response of which controls the rate of expansion and contraction of the sealing plate to match that of the rotor. In this way tip clearances between the stationary and rotating parts of the air seals are maintained substantially uniform throughout all operating conditions of the turbomachine.

Abstract: A coupling between a hub (10) and a shaft (11) has first and second splines (512,513; 530,531) connecting the hub to the shaft. The first splines extend axially and are straight while the second splines are helical. A nut (521) on the shaft urges the hub axially toward a shoulder (527) on the shaft. The first and second splines, being of different helix angles, co-operate to urge the spline faces circumferentially into engagement to take up any clearance therebetween. The different helix angles also have the effect of limiting axial movement of the hub under the nut load. On application of the nut at an initial moderate torque the hub takes up an initial axial position. On further, more powerful, application of the nut, the hub is urged axially against the shoulder (527) which provides a final limit to movement of the hub thereby to avoid undue circumferential stress in the splines.

Abstract: The fan rotor (10) of a gas turbine engine is driven by a shaft (16) having a first part (16A) supported in a first radial bearing (17) for rotation about an axis (16C). The shaft (16) further has a second part (16B) secured to the rotor for transmitting torque thereto. The second part (16B) is flexible in bending to allow radial displacement of the rotor (10) relative to the bearing (17). Normally, the rotor (10) is supported against said displacement by a second radial bearing (23). If, due to damage, a given dynamic imbalance on the rotor (10) is exceeded, the resulting unbalanced force (F) transversely to the axis (16C) shears the pins (21C) of a coupling (21) provided between the rotor and the second bearing (23). This then permits the rotor (10) to move eccentrically with respect to the axis (16C) by virtue of the resilience of the shaft portion (16B) thereby cushioning the bearing (17) against the force (F).

Abstract: A rotor assembly, particularly for a gas turbine engine, comprising a torsionally stiff drive shaft 16 mounted at two spaced locations in first and second bearings 22,23 which are substantially immovable bodily in radial directions. The drive shaft 16 has a flexible end portion 15 constituted by a shaft 25, projecting beyond the first bearing 23 which is more flexible in bending than the span of the drive shaft 16 between the first and second bearings 22,23. A support means 27 is mounted for rotation in a third bearing 28. The rotor 11 is mounted on the flexible end portion 15 of the drive shaft 16 to be driven thereby and is also mounted on the support means 27 for rotation in the third bearing 28. The third bearing 28 is capable of accommodating radial deflections of the support means 27 when the rotor becomes unbalanced.

Abstract: A cooled rotor blade for a gas turbine has an aerofoil in which there are longitudinally extending cooling fluid passages. At the tip of the aerofoil is located a separate, chordwise extending tube. The tube has apertures in its wall which correspond with at least some of the cooling fluid passages, whereby the spent cooling fluid from these passages may pass through the tube to rejoin the gas flow of the engine.

Abstract: A bearing assembly between an inner and an outer shaft has two rolling bearings and two hydrodynamic or squeeze film bearings. The one film bearing is arranged between the outer race of the one rolling bearing and the outer shaft to damp vibration of the inner shaft. The other film bearing is arranged between the inner race of the other rolling bearing and the inner shaft to damp vibration of the outer shaft.