Abstract: A fan blade (26) comprises a leading edge (44), a trailing edge (46), a concave wall portion (50) extending from the leading edge (44) to the trailing edge (46) and a convex wall portion (52) extending from the leading edge (44) to the trailing edge (46). A flexible wall (56) is arranged within the fan blade (26) to partially define a plurality of chambers (60) with an internal surface (54) of the convex wall portion (52). The flexible wall (56) is arranged substantially parallel to the internal surface (54) of the convex wall portion (52) and a plurality of walls (64) connect the internal surface (54) of the concave wall portion (50) and the flexible wall (56). The chambers (60) contain a fluid. The chambers (60) are interconnected by apertures (62) such that in operation deflection of the flexible wall (56) by vibrations of the fan blade (36) produce a flow of fluid between the chambers (60) through apertures (62), which is restricted by the apertures (62) to damp vibrations of the fan blade (26).

Abstract: A frangible coupling for interconnecting parts comprising a first ring and a second ring coaxially arranged relative to each other and axially joined via an annular array of fuse ligaments equidistantly spaced apart from each other. The ligaments are configured to fail when an abnormal radial load of a predetermined value causes the first and second ring to move out of their coaxial relationship. When all of the fuse ligaments are severed, the communication between the first and second rings is severed. This allows the first ring to move independently of the second ring, preventing the out of balance load on the first ring being communicated to the second ring.

Abstract: A damper seal 7, 21, 31 is provided in order to act within a mounting platform structure 3 for turbine blades 1, 2. The damper seal 7, 21, 31 includes an entrant surface 8, 28, 38 incorporating a number of paths 22, 32 to enable coolant flow across the entrant surface 8, 28, 38. The damper seal 7, 21, 31 acts to plug an aperture 9 in the structure 3 between adjacent blades 1, 2 and damper detrimental vibrations in the structure 3 which could damage the blades 1, 2. Thus, whilst contact portions 23, 33 are in vibrational coupling contact with the aperture 9, coolant airflow through the paths 22, 32 enables cooling of the seal 7, 21, 31 and areas of the structure 3 about the aperture 9.

Abstract: In one aspect the invention provides a friction welded component and a method of manufacture for such a component, comprising friction welding a reinforcement element (10) at an end cross-section thereof to a surface of a thin walled member (12) with an interlayer member (14) interposed between the reinforcement element and the surface of the thin walled member. The thin walled member and/or the interlayer are preferably of the same or similar material and the thickness of the thin walled member is preferably less than or equal to 6 mm and more preferably in the range 0.5 to 2 mm with the diameter of the reinforcement element being greater than 10 times the thickness of the thin walled member. The invention finds particular application in the fabrication of bosses to gas turbine aero-engine casings and fabricated nozzle components, for example.

Abstract: A turbine blade (20) has cooling air passageways (30) and (30a, 30b, 30c.) through the leading edge wall portion (24) which are positionally arranged so as to intersect each other within the wall thickness so as to transmit mechanical stresses into the thicker, non-perforated material of the blade aerofoil (22). Further passageways near the blade root portion (42) do not intersect, the reduced cooling in that area causes expansion and stress absorption.

Abstract: A brush seal (9) comprising a plurality of bristles packed together in a bristle layer (10). The bristles (10) extend from a first component (4) towards a facing surface of a second component (2). A movable plate (14) is disposed substantially parallel to and adjacent to the bristle layer (10). The plate (14) is movable relative to the bristle layer (10) in a direction parallel to the bristle layer (10). An edge (22) of the movable plate (14) adjacent to and facing the facing surface of the second component (2) is arranged to air ride on the facing surface of the second component (2). To promote the air riding the edge (22) of the movable plate (14) may be accordingly profiled. Alternatively the edge (14) may comprise an enlarged foot member (24) which defines an enlarged surface (26). Furthermore a recess (30) may be defined in the movable plate (14).

Abstract: In a nozzle guide vane assembly for a compressor or fan stage of a gas turbine engine each of the guide vanes is held in position between an outer casing and an annular inner ring by means of a rubber boot or collar at each end of the vane. Operational experience has shown potential for these assemblies to resonate within the engine, the cause of which is traced to the stiffness of the rubber collar. The present invention proposes as a solution a modified form of collar in which a stiffening plate is either bonded to the surface of the rubber or is incorporated into the construction during the rubber vulcanisation process. Alternatively or in addition the properties of the material from which the boots are moulded may be modified by the inclusion of chopped fibres of a range of materials.

Abstract: A method of laser trepan drilling diffuser type holes in a component which comprises directing the beam of the laser such that it drills a diffuser section on the beam entry side of the hole with the beam exiting the hole without interfering with the remaining non-diffuser part of the hole.

Abstract: A seal arrangement for a combustor is disclosed. The seal arrangement comprises a seal defining a first aperture, an inner combustor wall defining a second aperture, and an outer combustor wall defining a third aperture. The first and second apertures are arranged in line with each other to receive an article therethrough. The seal is arranged between the inner and outer combustor walls.

Abstract: An aircraft (10) comprises a wing (12) having an upper surface (16) and a lower surface (18) and at least one turbofan gas turbine engine (20) mounted on the wing (12). The axis (34) of the at least one turbofan gas turbine engine (20) is arranged substantially in the plane (14) of the wing (12) of the aircraft (10). The at least one turbofan gas turbine engine (20) has an intake, the intake comprising a hollow member (44) rotatably mounted coaxially with the at least one turbofan gas turbine engine (20) such that in use the hollow member (44) is rotatable between a first position, a low-speed condition, in which air flowing over and/or above the upper surface (16) of the wing (12) flows into the intake of the at least one turbofan gas turbine engine (20) and a second position, a high-speed condition, in which air flowing along and/or below the lower surface (18) of the wing flows into the intake of the at least one turbofan gas turbine engine.

Abstract: In one aspect of the invention a method of manufacturing a thin wall isogrid casing by a chip machining process comprises the steps of: positioning a substantially cylindrical casing (10) on a support (20); the support having a substantially continuous cylindrical support surface (22) engaging at least part of the inner or outer surface of the casing; and machining a plurality of recessed pockets in the said inner or outer surface of the casing opposite the surface engaged by the said support; whereby the support reacts loads acting on the casing by the chip machining tool during machining to minimise distortion of the casing and tearing of the pockets being formed. With this method isogrid pockets (14) can be chip machined, by drilling and/or milling etc, with pocket wall thicknesses of less that 1 mm.

Abstract: The performance of each component in the system is defined by performance parameters x, which are related to measurement parameters z expressed as a function h( ) of the performance parameters x and operating parameters w. The method comprises: (a) setting an assumed maximum number of fault affected components and defining a series of fault classes corresponding to possible outcomes in terms of faulty components, (b) creating an initial population of strings for each fault class, each comprising a plurality of elements corresponding to the performance and operating parameters (c) optimising for each class an objective function J(x,w) which gives a measure of the consistency between measured values and calculated values of the measurement parameters calculated using said function of the performance parameters and the operating parameters h(x,w), and (d) selecting the class having the best value of the objective functions.

Abstract: A lubrication arrangement for interlocking gears 2, 3 is configured by a housing 1 which incorporates sections 1a, 1b of a snail cross-section. Thus, rotating gears 2, 3 are positioned to generate a centrifugal pumping effect between those gears 2, 3 and the housing sections 1a, 1b which drives scavenged oil flow into a volute 11 formed by the opposing surface of the housing 1a, 1b. The scavenged oil is driven in the direction 13 towards an off-take 12 configured such that there is a minimum available cross-sectional area 14 between the housing at the intermeshing of the gears 2, 3 at an interlocking location 4. In such circumstances the scavenged oil is driven at relatively high speed through the off-take 12. Such relatively high speed scavenged oil 15 can be used for displacement scavenging in other parts of an engine or machine where problems exist with oil residence.

Abstract: A bearing arrangement is provided within a bearing housing 1 in which a bearing assembly formed by inner and outer bearing races 2, 3 and bearing member 4 is subject to a drawing force to remove cooling and lubricating oil. This drawing force is created by an adjacent gear 7 through its back face which normally incorporates vanes 12. When rotating the gear 7 creates a drawing pressure scavenging oil from the bearing assembly. This drawing pressure is facilitated by a shroud 13 in order to create an effective centrifugal pump such that the oil passes up through the vanes and is then scattered by the gear's centrifugal force towards a volute 10 for collection.

Abstract: A gas turbine engine (10) includes a first fire zone (Zone 3) in the region of a core of the engine and a second fire zone (Zone 1) in the region of a fan case of the engine, the first and second fire zones being separated by fire walls. The first fire zone is located generally radially inwardly of the second fire zone but includes a bifurcation part which extends radially outwardly of the remainder of the zone for limited circumferential extent. The engine further includes a disconnect panel (52) mounted on the fan case (32) to extend radially outwardly therefrom, the disconnect panel (52) forming a fire wall and providing means for pipes and harnesses (44) to be routed therethrough.

Abstract: A method of controlling turbine case cooling in a gas turbine engine, the method including monitoring the present state of the engine 32 and using a predictive model based system 44, 46 to predict the future thermal expansion of the turbine case 12 and turbine blades 28, and controlling cooling of the turbine case 12 in response to said prediction to provide a required gap 30 over time.

Abstract: The minimum fuel flow to a combustor of a gas turbine engine is controlled in response to the combustor inlet temperature T3 in order to provide a FAR stability margin which responds to the combustor inlet temperature. This enables the FAR stability margin to be reduced when the risk of flame out is low, for example when the combustor entry temperature is high, while increasing the FAR stability ratio when the combustor entry temperature is low, ie when the engine is idling or when water is ingested.

Abstract: A component such as a turbine blade for a gas turbine engine has a cooling arrangement comprising a supply passage 18 within the blade from which extend cooling passages 28 of a first array which open at discharge openings 29, for example at a trailing edge of the blade. Cooling passages 30 of a second array extend into the blade from discharge openings 31, and intersect the passages 28. The passages 30 terminate short of the supply passage 18. As a result of this arrangement, the limiting flow area for cooling air is defined by the cooling passages 28 of the first array, and is not affected by the accuracy with which the cooling passages 30 of the second array intersect the cooling passages 28 of the first array.

Abstract: A method of processing oscillatory response data from a resonant system is provided, the method comprising: obtaining data measuring an oscillatory response of the system at a plurality of evenly spaced time intervals; obtaining a plurality of reference frequencies from said data at a plurality of times in said data, each reference frequency preferably being the natural frequency of a mode of the response at the respective time or an estimate of said natural frequency; and transforming said data to an uneven data set having unevenly spaced time intervals by adjusting said evenly spaced time intervals according to the values of said measured reference frequencies. The method can transform non-stationary response data to make it effectively stationary, and thus in a more useful form for further analysis. A method of analysing a resonant system and an apparatus for processing oscillatory response data are also provided.

Abstract: An inertia friction welding process comprises: a) providing first and second work pieces to be welded together; b) imparting motion to the first work piece relative to the second work piece thereby imparting kinetic energy to the first work piece relative to the second work piece; c) applying a predetermined force to move one or both of the first and second work pieces towards the other to create an upset length in the work pieces; characterised by; d) measuring the rate of motion of the first work piece relative to the second work piece; e) determining a predicted final upset length from the said measured rate of relative motion and said forth; f) comparing the predicted final upset length with a desired final upset length; g) adjusting the aforesaid kinetic energy to achieve substantially the desired final upset length.