Abstract: A fan disc is provided for supporting fan blades of a gas turbine engine. The fan disc has a disc body having axially extending slots for receiving, in use, dovetail root fixings of a circumferential row of fan blades. The fan disc further has an annular drive arm which extends radially inwardly from a forward portion of the disc body to a connector for engaging, in use, with a corresponding connector portion of a drive shaft of the engine. The fan disc further has a hoop stiffening ring which is removably mounted to a rear portion of the disc body, the stiffening ring being axially spaced from the drive arm to increase the torsional stiffness of the fan disc.

Abstract: Method of manufacturing a metal matrix composite component includes the steps of providing a first tubular member having a first end and an opposite second end, the first tubular member's first end being formed as a first end block; positioning a metal matrix composite tubular member concentrically the first tubular member; positioning a second tubular member concentrically over metal matrix composite tubular member, second tubular member having a first end and an opposite second end, the second tubular member's second end being formed as a second end block; welding first tubular member's first end to the second tubular member's first end, and the first tubular member's second end to second tubular member's second end, to join the first and second tubular member and thereby to form a metal matrix composite preform; and consolidating metal matrix composite preform by a hot isostatic pressing process to form the metal matrix composite component.

Abstract: A fan disc is provided for supporting fan blades of a gas turbine engine. The fan disc has a disc body having axially extending slots for receiving, in use, dovetail root fixings of a circumferential row of fan blades. The fan disc further has an annular drive arm which extends radially inwardly from a forward portion of the disc body to a connector for engaging, in use, with a corresponding connector portion of a drive shaft of the engine. The fan disc further has a hoop stiffening ring which is removably mounted to a rear portion of the disc body, the stiffening ring being axially spaced from the drive arm to increase the torsional stiffness of the fan disc.

Abstract: A hydraulic fluid transfer coupling has a stator, a first coaxial rotor, and a second coaxial rotor. The first rotor is radially inwards of the stator, the second rotor is radially outwards of the stator, at least part of the first rotor axially overlapping with the stator, and at least part of the second rotor axially overlapping with the stator. The first rotor carries one or more first rotating fluid lines, and the second rotor carries one or more second rotating fluid lines. The stator carries one or more first static fluid lines and second static fluid lines. Each pair of a first rotating fluid line and the corresponding first static fluid line are fluidly coupled and each pair of a second rotating fluid line and the corresponding second static fluid line are fluidly coupled. Hydraulic fluid is transferable between each static fluid line and the corresponding rotating fluid line.

Abstract: A mounting system for mounting a blade to a rotor body includes a pitch control mechanism including an anchor and a pitch change rod extending radially outwardly from the anchor to join to a base of the blade. The anchor and the rod are rotatable about the longitudinal axis of the rod to vary the blade pitch. The pitch control mechanism further includes a torque-transmitting formation between the blade and the anchor such that pitch-varying torque can be transmitted to the blade through the torque-transmitting formation while allowing relative radial movement between the blade and the anchor. The system includes a primary bearing formation, which transmits blade centrifugal loads to the rotor body while accommodating variation of the blade pitch, and secondary bearing formation, which transmits pitch change mechanism centrifugal loads to the rotor body while accommodating rotation of the anchor and the rod during variation of the blade pitch.

Abstract: An assembly, for example in a gas turbine engine, includes a rotatable component supported by a bearing in a support structure. A sealing arrangement includes a non-rotating sealing ring which makes sealing contact with sealing features on the rotatable component. The non-rotating sealing ring is radially displaceable with respect to the support structure by means of ribs which engage axially facing support faces of the support structure. The non-rotating sealing ring is radially located by an outer, non-rotating, race of the bearing, by means of a locating surface on a locating body of the non-rotating sealing ring. As a result of this arrangement, the running clearance at the sealing arrangement can be maintained, despite radial displacement of the rotatable component with respect to the support structure, and despite thermal and mechanical deflections of the support structure.

Abstract: A control mechanism is provided for moving at least two components of a gas turbine engine. The control mechanism comprises a movable actuation rod and a first linkage arrangement which includes a first bell crank connecting the actuation rod to a first component. Movement of the actuation rod produces an output motion of the first bell crank which in turn drives movement of the first component. The control mechanism further comprises a second linkage arrangement which includes a second bell crank connecting the actuation rod to a second component. Movement of the actuation rod produces an output motion of the second bell crank which in turn drives movement of the second component. The first and the second linkage arrangements are configure so that over a predetermined range of movement of the actuation rod the first component is moved which the second component is not moved.

Abstract: A duct wall of a fan casing of a gas turbine engine comprises an intake section and a containment casing, which are interconnected by bolts at flanges. An acoustic flutter damper is provided between the flanges to reduce or eliminate flutter arising in blades of the fan at certain important operating conditions. The damper provides flexibility at the connection between the intake section and the containment casing so that, in the event of detachment of a blade or a bladed fragment, the resulting deflection wave in the containment casing can be accommodated by displacement and/or deformation of the acoustic flutter damper, reducing the risk that the bolts will shear to allow the intake section and the containment casing to become detached from each other. The acoustic flutter damper may comprise a circumferential array of separate segments.

Abstract: A support structure is provided for attaching a gas turbine engine to a pylon. The gas turbine engine has an engine casing surrounding an engine core, and the pylon has first and second attachment positions, the second attachment position being forward of the first attachment position relative to the working gas flow direction through the engine. The support structure has three elongate members joined to form a triangular frame encircling the engine casing. A first vertex of the triangular frame attaches to the pylon via a first attachment arrangement at the first attachment position. Two thrust struts respectively extend from the other two vertices of the triangular frame and attach to the pylon via a second attachment arrangement at the second attachment position. Three engine connection formations extend from the respective vertices of the triangular frame to positions on the engine casing to connect the support structure to the engine casing.

Abstract: A mounting arrangement of a gas turbine engine comprising a core engine, surrounded by a nacelle having a bypass duct, the mounting arrangement comprising a front mount, a rear mount and characterized by the mounting arrangement further comprising a fail-safe mount axially spaced from the front and rear mounts. The fail-safe mount comprises a number of A-frames connecting the core engine and the bypass duct. In normal operation the fail-safe mount does not transmit loads between the engine and a pylon, except in the event of damage to either the front or rear mounts.

Abstract: A gas turbine engine fan casing duct wall comprises an intake section and a containment casing, provided respectively with flanges. An acoustic flutter damper is secured between the flanges. The acoustic flutter damper has a skin accommodating an internal structure that dampens fan blade flutter. The skin is secured to the flanges at separate locations. In normal operation of the engine, the internal structure is sufficiently robust to support loads transmitted through the acoustic flutter damper between the intake section and the containment casing. If a blade or blade fragment detaches, the resulting deflection wave in the containment case ruptures the internal structure, and the load path between the intake section and the containment casing passes along the skin, which consequently maintains the connection between the intake duct and the containment casing, while permitting substantial radial deflection of the containment casing relative to the intake section.

Abstract: A load transfer arrangement is provided to act as a stabiliser for utilisation in centring rotational instabilities which may occur in rotor devices such as those within a gas turbine engine. By providing a fixed screw thread path which comprises a groove having channels and having constrictions and which define clearance crowns an acceptable eccentricity range it is possible to slow screw thread driving motion and therefore load transfer only to the positions where the rotational eccentricity enters tapers leading to the constrictions. In such circumstances an orbit thread is then progressively brought into confinement and continuous engagement with a fixed screw thread defined by crowns of channels of the fixed screw thread path defined by the continuous groove through the channels. In such circumstances wide eccentricity is allowed initially but as rotational speed reduces greater and more continuous driving motions are provided whilst avoiding excessive loading during early stage operation.

Abstract: A hydraulic fluid transfer coupling has a stator, a first coaxial rotor, and a second coaxial rotor. The first rotor is radially inwards of the stator, the second rotor is radially outwards of the stator, at least part of the first rotor axially overlapping with the stator, and at least part of the second rotor axially overlapping with the stator. The first rotor carries one or more first rotating fluid lines, and the second rotor carries one or more second rotating fluid lines. The stator carries one or more first static fluid lines and second static fluid lines. Each pair of a first rotating fluid line and the corresponding first static fluid line are fluidly coupled and each pair of a second rotating fluid line and the corresponding second static fluid line are fluidly coupled. Hydraulic fluid is transferable between each static fluid line and the corresponding rotating fluid line.

Abstract: A mounting system for mounting a blade to a rotor body includes a pitch control mechanism including an anchor and a pitch change rod extending radially outwardly from the anchor to join to a base of the blade. The anchor and the rod are rotatable about the longitudinal axis of the rod to vary the blade pitch. The pitch control mechanism further includes a torque-transmitting formation between the blade and the anchor such that pitch-varying torque can be transmitted to the blade through the torque-transmitting formation while allowing relative radial movement between the blade and the anchor. The system includes a primary bearing formation, which transmits blade centrifugal loads to the rotor body while accommodating variation of the blade pitch, and secondary bearing formation, which transmits pitch change mechanism centrifugal loads to the rotor body while accommodating rotation of the anchor and the rod during variation of the blade pitch.

Abstract: An annular flow mixer is provided for use in a gas turbine engine. A core generator of the engine provides an annular duct for the flow of working gas, which exhausts from the duct through the flow mixer. The flow mixer has a plurality of circumferentially spaced exhaust chutes from which the working gas exits in respective exhaust plumes. The exhaust chutes are configured such that, at the discharge end of the flow mixer, a radially outer portion of each exhaust chute radially overlaps with a radially inner portion of at least one adjacent exhaust chute.

Abstract: In order to accommodate loading in a number of situations such as with regard to thrusts in a gas turbine engine it is known to provide thrust bearings. These thrust bearings can be large and may be difficult to accommodate. By providing a duplex or multiplex thrust bearing which may be of increased axial length but reduced radial width easier accommodation may be achieved. By providing a thrust element 27 which compromises a balance beam from which extend elastic hinges to a mounting to a fixed bearing frame and ends of bearing races 21, 22 an appropriate thrust response can be achieved dependent upon bearing loads presented through bearing elements 23, 24. By rotation of the balance beam and flexing of the elastic hinges 30, 31, 32 an appropriate bearing load share is achieved.

Abstract: An assembly, for example in a gas turbine engine, includes a rotatable component supported by a bearing in a support structure. A sealing arrangement includes a non-rotating sealing ring which makes sealing contact with sealing features on the rotatable component. The non-rotating sealing ring is radially displaceable with respect to the support structure by means of ribs which engage axially facing support faces of the support structure. The non-rotating sealing ring is radially located by an outer, non-rotating, race of the bearing, by means of a locating surface on a locating body of the non-rotating sealing ring. As a result of this arrangement, the running clearance at the sealing arrangement can be maintained, despite radial displacement of the rotatable component with respect to the support structure, and despite thermal and mechanical deflections of the support structure.

Abstract: A support structure is provided for attaching a gas turbine engine to a pylon. The gas turbine engine has an engine casing surrounding an engine core, and the pylon has first and second attachment positions, the second attachment position being forward of the first attachment position relative to the working gas flow direction through the engine. The support structure has three elongate members joined to form a triangular frame encircling the engine casing. A first vertex of the triangular frame attaches to the pylon via a first attachment arrangement at the first attachment position. Two thrust struts respectively extend from the other two vertices of the triangular frame and attach to the pylon via a second attachment arrangement at the second attachment position. Three engine connection formations extend from the respective vertices of the triangular frame to positions on the engine casing to connect the support structure to the engine casing.

Abstract: A hollow aerofoil (30) comprises an aerofoil portion (40) having a leading edge (42), a trailing edge (44), a concave pressure surface wall (46) extending from the leading edge (42) to the trailing edge (44) and a convex suction surface (48) extending from the leading edge (42) to the trailing edge (44). The concave pressure surface wall (46) and the convex suction surface wall (48) are integral and define a cavity (50). A plurality of webs (52) extend across the cavity (50) between the concave pressure surface wall (46) and the convex suction surface wall (48). At least one of the webs (52A) extends substantially perpendicularly to the concave pressure surface wall (46) and the convex suction surface wall (48) and at least one of the webs (52B) extends substantially diagonally to the concave pressure surface wall (46) and the convex suction surface wall (48).

Abstract: A gas turbine engine (10) comprising a rotating member (16), a support structure (22) and a centering device (30), the centering device (30) centers the rotation of the rotating member (16) which is supported within the support structure (22), characterized in that the device includes a first member (34) and a second member (36) that contact one another, one of the first and second members (34, 36) extending from the rotating member and the other of the first and second members (34, 36) extending from the support structure (22), the first member (34) comprises a biasing surface (46) and the second member (36) comprises a seating surface (40), the device requiring a predetermined force to be applied to move between a centered condition and a first out of center condition and in the centered condition the first member (34) is seated against the seating surface (40) of the second member (36), and in the first out of center condition the first member contacts the biasing surface (46) which is arranged to provide