Abstract: An arrangement for reducing vorticity downstream of a turbine nozzle guide vane 34 in a gas turbine engine. The arrangement including directing cooling air through the guide vane 34 and out through outlets 40 in directions to counteract the wave vorticity produced downstream of the guide vane 34.

Abstract: A cantilevered stator stage for the axial compressor 14 of a gas turbine engine 10 in which the stator tips 26 rub against an abrasive section 24 on the rotor drum 22 during initial running of the engine 10 to abrade the tips 26 of the stator to provide optimised stator tip running clearance.

Abstract: Laser welding apparatus, in which a laser beam is impinged upon a component to be welded at a laser beam impingement point, wherein a plasma suppressor is arranged to impinge a jet of gas on the component at an angle to its surface, flowing towards the laser beam impingement point.

Abstract: A combustor assembly for a gas turbine engine comprises a casing arrangement defining an aperture and a seal element mounted on the casing arrangement through which a component of the combustor can extend. The seal element comprises a relatively flexible force absorbing portion and a relatively rigid sealing portion. The force absorbing portion is provided between the sealing portion and the casing arrangement. The force absorbing portion is resiliently deformable to absorb force during movement of the casing arrangement. Such resilient deformation restricts transmission of the forces to the sealing portion. The seal element may be configured to carry a seal member.

Abstract: Two metal blocks (50, 52) are welded to respective metal sheets (30, 32) to form sealed assemblies. The sealed assemblies are then diffusion bonded together to form two metal preforms (54, 56). The thick ends (36) and (40) of the metal sheets (30, 32) and the metal blocks (50, 52) are hot formed so that a continuation of the plane X of the first surfaces (42, 46) of the metal sheets (30, 32) extends through and across the metal blocks (50, 52). The metal preforms (54, 56) are machined to remove the portion of the metal blocks (50, 52) extending above the first surfaces (42, 46) of the metal sheets (30, 32) respectively. The metal preforms (54, 56) and a metal sheet (58) are assembled into a stack (64). The metal preforms (54, 56) and the metal sheet (58) are diffusion bonded together and then superplastically formed to produce a hollow fan blade (10). The method enables thinner metal workpieces with better microstructure to be used and increases the yield of metal workpieces.

Abstract: The present invention relates to a seal arrangement in which a substantially labyrinth type seal is utilised between a rotating component and a stationary component such as a housing. An edged fin of the seal arrangement incorporates a slot nozzle or a slot nozzle is associated with a fin in order that fluid flow through those slot nozzles either impinges upon opposed surfaces or at least narrows the available leakage gap width for greater sealing efficiency. Typically, several seal arrangements in accordance with the present invention and possibly in association with simple barrier fins are combined in an assembly to provide an appropriate acceptable combined operational sealing efficiency in a turbine engine.

Abstract: The surge margin of a fan or compressor stage may be increased by radial, circular grooves in the casing (2) encircling the rotor stage. The present invention provides improved aerodynamic performance by replacing circumferential grooves by multiple helical grooves 18. Preferably the grooves (18) have multiple start and end positions (20,22) spaced apart around the casing (2) and at least the downstream ends (22) of the grooves (18) are tapered to aid expulsion of particles in the grooves (18).

Abstract: The present invention is a method of monitoring the health of a fuel system 30 of a gas turbine engine 10. The fuel system 30 comprising a fuel-metering valve 36, a hydraulic control valve servo pressure line 40 and a control pressure line 39. The fuel-metering valve comprises a hydraulic control valve solenoid 36 for metering the flow of fuel and a fuel filter 38 and, in use, a current is applied to the solenoid 38 to control the required fuel demand to fuel nozzles 25. The method comprises the steps of; measuring either the percentage difference between fuel metering valve demand and actual positions or the percentage difference in pressure between the servo pressure line 40 and the control pressure line 39, comparing the differential to a predetermined level, when that predetermined level is reached a warning is given. Thereby the engine may be scheduled for service before unsatisfactory performance of the fuel system is experienced.

Abstract: Rotary apparatus for a gas turbine engine comprises a rotor assembly and first and second stator assemblies mounted coaxially with respect to each other. The first stator assembly is upstream of the second stator assembly, and the second stator assembly is upstream of the rotor assembly. The rotor assembly comprises an annular array of rotor blades, and each stator assembly comprises an annular array of stator vanes. Each vane has a leading edge and a trailing edge. The stator assemblies are circumferentially translatable relative to each other between a first condition and a second condition. In the first condition, at least a part of each vane of the second stator assembly extends beyond the trailing edge of the respective vane of the first stator assembly.

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 whilst 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 emphasised by residual bonding material remaining after an attempted bonding process upon the anti-bonding layer.

Abstract: A lubricant arrangement is provided for multiple feed pipes to bearings lubrication system. In order to ensure a feed pipe remains substantially full of lubricant fluid, a drainage restrictor configuration is provided. This configuration typically comprises an anti siphon tube, accumulator, a fluid head between a supply pipe and the feed pipe as well as a final loop in the feed pipe formed by limbs. In such circumstances, drainage of lubricant fluid from other feed pipes for other bearings does not siphon lubricant fluid from the feed pipe which may be subject to potential coking as a result of high temperatures and air.

Abstract: A lightweight component in the form of an outlet guide vane 10 for a gas turbine engine. The vane 10 being filled with hollow metal ellipsoid members 12 in a solid metal outer 14.

Abstract: Four actuators are instructed to move to a condition indicated by a demand line 81. Their actual conditions are indicated by four arrows. The method determines if the range 84 of actual conditions exceeds a threshold value, representing an unacceptable mismatch of actuator positions. This comparison is used to establish further demand instructions. For example, if the range is too great, and the average 82 is below the demand line 81, the devices are instructed to move to the upper extreme position at 88. If the average position 82 is above the demand line 81, the devices are instructed to move to the lower end of the range, at 90. This results in the actuator positions moving together, as they also move toward the demand line 81, reducing risks associated with actuator mismatches.

Abstract: A rotor stage (13, 14, 15, 17, 18, 19) of a gas turbine engine (10) comprises an annular retaining plate (38) capable of preventing axial movement of blades (30). The retaining plate (38) is secured to the disc (32) via a bayonet arrangement (49). A locking assembly (48) is provided to prevent relative rotation between the disc (32) and the retaining plate (38). The locking assembly (48) comprises a locking plug (50) configured in a generally Y-shaped cross section having a channel portion defined by arms (56), which engage upstream and downstream of the retaining plate (38) and a leg part (58) configured to span between bayonet parts (40 and 42), thereby preventing relative rotation between the disc (32) and the retaining plate (38). The assembly (48) further comprises a securing plate (52) configured to span between circumferentially adjacent castellations (40) thereby preventing the locking plug (50) disengaging the disc (32) and retaining plate (38).

Abstract: An arrangement for sealing an opening formed in a wall for receiving a member. The arrangement comprises a sealing member with a passage, and the sealing member is moveably mounted on the wall adjacent to the opening such that the sealing member passage is substantially co-axial with the opening in the wall. Biasing means for biasing the sealing member towards the wall are also provided.

Abstract: Previous retention arrangements have suffered from fretting or high contact stresses as a result of rolling between members retained by a retainer ring in the form of a split ring. In order to address these problems a retainer arrangement is provided in which a retainer is arranged at an inclined angle relative to a mounting axis for members such as a coverplate and mounting disc. In such circumstances, in view of the angular presentation of the retainer, distribution of axial thrust loads can be aligned and through shaping of the retainer in terms of symmetry it will be understood centrifugal loads can be balanced as required. Typically, the retainer as indicated will be a split ring and the retainer for assembly and disassembly will be moved in a displacement direction consistent with the inclined angle so that the retainer enters a recess to allow disassembly or assembly of the members.

Abstract: A variable vane arrangement (36) for a compressor (26) of a gas turbine engine (10) comprises a plurality of circumferentially arranged vanes (38), a plurality of operating levers (64) and a control ring (66). Each vane (38) is pivotally mounted to a casing (30) of the compressor (26). Each operating lever (64) is pivotally mounted at a first end (68) to the control ring (66) and is mounted at second end (70) to a respective one of the vanes (38). The second end (70) of each operating lever (64) comprises a multi-sided aperture (72) and each vane (38) has a multi-sided spindle (60) which locates in the multi-sided aperture (72) of the respective operating lever (64). Each operating lever (64) has a drive member (74) located in the multi-sided aperture (72) and around the multi-sided spindle (60) of the respective vane (38). Each drive member (74) engages the respective multi-sided aperture (72) and the respective multi-sided spindle (60) to transmit drive from the operating lever (64) to the vane (38).

Abstract: A database arrangement is provided which presents a user with a results table 56. This had two dimensions. Column headings show classification headings at a selected level of a classification structure. The rows are classified with additional identification of the content of data items within the database. Each point of the table shows the number of data items meeting the two criteria. The user can thus see the number of results available from various alternative refinements of a search strategy, before the search strategy is restricted.

Abstract: A welding torch (10) for welding on a component has an electrode (12) within a nozzle (14) through which a flow of gas passes. A shield (20) defines an enclosure (22) around the nozzle (14). Means are provided for supplying weld filler material (18) into the vicinity of the electrode (12) through the shield (20). One end of the shield (20) is attached to the welding torch (10). The other end of the shield (20) is open and extends towards the component (16). An inflatable seal (28) is mounted on the end of the shield (20) to seal between the shield (20) and the component (16).

Abstract: A vane assembly for a gas turbine engine, the assembly including a plurality of vanes 14 with an asymmetric organic metal/ceramic matrix composite lay up, such that when the vanes 14 are placed in tension or compression the profile of the vane 14 will alter by twisting or untwisting. Other materials may be provided for the vanes 14, and/or other methods may be used for placing the vanes 14 in tension or compression to provide positive changes to the profile thereof.