Abstract: Disparities between optimum engine thrust for aircraft operation and power necessary to drive an ancillary machine such an electrical power generator can cause problems within a turbine engine. Clearly, it is necessary to continue developing sufficient electrical power for control and other systems within an aircraft despite aircraft thrust requirements. Previously, some compressed air flow has been bypassed in order to maintain compressor stability, but unfortunately such bypass systems within turbine engines can have a thrust recovery regime such that there is excess thrust in comparison with that actually necessary.

Abstract: The present invention relates to an aerofoil blade comprising a root, a tip, a leading edge and a trailing edge. At least part of the tip and at least a part of the trailing edge of the blade are reinforced by at least one portion of drapable reinforcing material wrapped around the tip and trailing edge.

Abstract: A balanced rotor of a turbine engine, having a rotor disc with a circumferential slot and a row of rotor blades mounted in the slot and a balance weight having a land which extends beneath the root of a blade and having a mass-adjustment protrusion extending from the land in a radial direction relative to the axis of the rotor component and which lies wholly between the blade root and an adjacent blade root.

Abstract: A propfan engine has a power-producing core, a plurality of nozzles for exhausting exhaust gas from the core, and a row of propeller blades rotatable about an axis. The blades are positioned downstream of the exhaust nozzles. The exhaust nozzles are rotatable about said axis. The nozzles can be aligned with the gaps between successive propeller blades in order to reduce noise during operation of the engine.

Abstract: The present invention relates to a reinforcing tip cap for an aerofoil blade. The tip cap comprises a body for attaching to the tip of an aerofoil blade and a plurality of abrading elements fixed in the body for abrading a surface against which the tip cap rubs in use.

Abstract: Breather air, containing oil mist, is discharged from a nacelle 4 of a gas turbine engine through an exhaust port 26 at a surface 22 of the nacelle 4. Energised air, at relatively high velocity is discharged from a clean air outlet 28, and forms a barrier between the breather air and the external surface 22, so preventing contamination of the surface 22 by oil deposited from the breather air.

Abstract: A gas turbine engine comprising a nacelle and a breather duct. The breather duct provides communication between a component of the engine within the nacelle and the exterior of the nacelle and opens at an exhaust port on the external surface of the nacelle. There is a clean air outlet slot located downstream of the exhaust port and arranged to expel, in use, a sheet flow of clean air to form an aerodynamic barrier between the external surface of the nacelle and a flow of breather air expelled from the exhaust port.

Abstract: A composite blade (28) comprises a root portion (38) and an aerofoil portion (40). The aerofoil portion (40) has a tip (50) remote from the root portion (38). The aerofoil portion (40) has a leading edge (42), a trailing edge (44), a suction surface (46) extending from the leading edge (42) to the trailing edge (44) and a pressure surface (48) extending from the leading edge (42) to the trailing edge (44). The composite blade (28) comprises reinforcing fibers (62) arranged in a matrix material (63). The tip (50) of the aerofoil portion (40) is arranged to define a recess (66), an insert (68) is arranged in the recess (66) and the insert (68) comprises an abradable material.

Abstract: Within gas turbine engines 10 it is necessary to provide fixed vanes which comprise an aerofoil in the gas flow through the gas turbine engine 10. These vanes are subject to significant stressing. Therefore it is generally necessary to secure the vane at one end 103 through an appropriate bond such as brazing while at another end a friction damping response is achieved. By providing an anti-bonding layer it is possible to prevent a mechanical bond being formed at the friction damping end 105. Furthermore, a tight fit can be emphasized by residual bonding material remaining after an attempted bonding process upon the anti-bonding layer.

Abstract: An annulus filler for mounting to a rotor disc of a gas turbine engine bridges the gap between adjacent disc blades. The annulus filler has a lid defining part of an airflow surface for air drawn through the engine; a separate support connectable to the lid and to the rotor disc with an engagement portion of the support extending radially past a substantially adjacent region of the lid; and a retainer configured to interconnect the lid and the support by engaging each engagement portion of the support and adjacent regions of the lid, the retainer defining another part of the airflow surface. The annulus filler can be configured to allow mounting to the rotor disc, where the support is connected to the rotor disc without the lid, and then the lid is mounted to the support such that each engagement portion remains visible from the lid's radially outermost side.

Abstract: A hydraulic stepper motor comprising three hydraulic ports each coupled to a piston that is actuatable between pressurised and depressurised configurations; and a contoured cam surface having at least one peak and trough and arranged to react against the pistons, the cam surface coupled to an output shaft; whereby actuation of one of the pistons moves the cam surface until a trough reacts against one or more pressurised pistons.

Abstract: A fluid flow control device for regulating the flow of fluid in a passage comprises an annular fixed body having at least one aperture in an annular surface thereof, through which fluid is arranged to flow in use, and a thermally responsive annular valve element mounted concentrically with respect to the fixed body and whose configuration is changeable with temperature so as to control the flow of fluid through the at least one aperture.

Abstract: A turbofan gas turbine engine comprises a fan and an intake duct upstream of the fan. The fan comprises a fan rotor having a plurality of fan blades. The intake duct has a liner, the liner comprising an acoustic liner positioned upstream of the fan and a buzz-saw tone noise liner positioned upstream of the acoustic liner. The buzz-saw tone noise liner is positioned substantially at, or near, an upstream end of the intake duct. The intake duct has a lip and the buzz-saw tone noise liner is positioned at, or near, the lip.

Abstract: Loss reduction apparatus for a fluid transfer system includes a fluid device. The fluid device defines a first fluid path along which a greater part of a fluid flows in a first condition, and a second fluid path along which a greater part of the fluid flows in a second condition. The apparatus is arranged so that when a leak occurs at a location in the system, the leak causes a relative reduction in fluid pressure at the location, which moves the device from the first condition to the second condition.

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: Fan flutter is a significant problem with regard to gas turbine engines and can lead to premature failure and unacceptability with respect to engine operation. Traditional acoustic liners for noise abatement are formed to reduce environment noise. Fan flutter frequencies are typically much lower than community noise targeted by traditional acoustic liners, and therefore require different approaches with respect to attenuation. By altering the acoustic propensities of the intake duct, it is possible to increase the safe operating envelope of the engine. The flutter attenuators according to this invention are optimised so that they occupy the minimum area of the intake duct, and so can be accommodated more easily (without significantly compromising the area available for liners targeting community noise, for example).

Abstract: A method of manufacturing a blisk comprising a disc joined to an aerofoil, wherein a union piece of partially sintered powder and having an alignment feature is provided. The union piece is connected between the disc and the aerofoil, which is aligned relative to the disc by the alignment feature of the union piece. Heat and pressure is subsequently applied to consolidate the first workpiece, union piece and second workpiece.

Abstract: A method of manufacturing a blade comprising: applying a stop-off material in a first predetermined pattern between a first layer and a membrane so as to prevent a diffusion bond from forming between the first layer and the membrane across said first predetermined pattern; and applying the stop-off material in a second predetermined pattern between a second layer and the membrane; wherein the first and second predetermined patterns are arranged to allow a diffusion bond to be formed along the blade tip edge, the diffusion bond along the blade tip edge extending across the blade in a chord-wise direction; applying the first and second predetermined patterns so that over at least a first portion of the blade chord at the blade tip, a greater portion of the first layer at the tip edge, extending in a span-wise direction, is diffusion bonded to the membrane than the opposing second layer.

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 seal and method of making seals utilises folds in order to form creases in a length of material such that the creases reinforce individual seal elements or surfaces whilst perforations or slots in a seal edge allow air leakage from one side of the seal element or surface to the other. Thus, air pressurisation can take place between spaced seal elements or surfaces and this allows air flotation or riding of a rotating component relative to a static housing component. The perforations are typically graduated from the seal edge in order to provide the best pressurisation and air-riding effect for proximity or gap control between the sealing edge and the rotating component surface. The slots effectively provide flexibility to the sealing edge such that the seal component emulates a brush seal.