Abstract: A cowl structure (18) for a gas turbine engine (10) comprises an outer skin (26) defining a first path for a load applied to the engine (10). The cowl structure (18) includes an inner skin (24) defining a second path for the load. The inner and outer skins (24, 26) are constructed such that a major proportion of the load is transmitted along the first path.

Abstract: A rotor drive (32) for a gas turbine engine (10) comprising a main drive body (44) having attachment lugs (46) on its radially outer port. The attachment lugs (46) are formed from a different material to the main drive body (44) and are bonded to the main drive body (44) by friction bonding.

Abstract: An air/oil separator (40) comprises a rotor (60) and a casing (62) surrounding the rotor (60). The casing (60) has an inlet (64) at a first axial position (A) for the supply of an air and oil mixture into the air/oil separator (40). The rotor (60) has an outlet (66) for discharging cleaned air from the air/oil separator (40). The rotor (60) carries a plurality of porous members (68, 70, 72). The porous members (68, 70, 72) have an inlet (74) at a second axial position (B) and an outlet (76) at a third axial position (C). The third axial position (C) is arranged axially between the first axial position (A) and the second axial position (B). A first passage (88) supplies the air and oil mixture from the inlet (64) in the casing (62) to the inlet (74) to the porous members (68, 70, 72). A second passage (94) supplies cleaned air from the porous members (68, 70, 72) to the outlet (66) in the rotor (60).

Abstract: A method of machining a workpiece having a protective surface coating, the said method comprising directing a laser beam at the surface of a workpiece to be cut, welded or drilled by the laser beam at an angle of inclination with respect to the said surface; directing a jet of fluid towards the point of incidence of the laser beam on the surface of the workpiece; characterised in that the said jet of fluid is angled with respect to the said laser beam.

Abstract: An electrical conductor winding (70) comprises a plurality of laminates of electrical insulation (72). Each laminate of electrical insulation (72) has a slot (78) on one surface (76). Each laminate of electrical insulation (70) has an electrical conductor (82) arranged in the slot (78). An electrical connector (84) connects the electrical conductor (82) in one laminate of electrical insulation (78) with the electrical conductor (82) in an adjacent laminate of electrical insulation (72). The laminates of electrical insulation (72) are arranged such that the surface (74) of one laminate of electrical insulation (72) abuts and is bonded to the surface (76) of an adjacent laminate of electrical insulation (12). The laminates of electrical insulation (12) comprise a glass-ceramic material. The electrical conductor windings allow active magnetic bearings, electric motors and electric generators to be used at temperatures up to 500° C. for example in gas turbine engines.

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 gas turbine engine turbine blade (20) has cooling air holes (38) arranged in groups, the holes (38) in one group and which span that part of the leading edge (34) that spans the hottest part of the blade (20), are more closely spaced than the remainder of the holes (38), thereby ensuring the provision of the most cooling air, where it is most needed.

Abstract: An aerofoil blade or vane for a gas turbine engine comprises a body member having an inner end for mounting the blade on a shaft and an outer or tip end. A plurality of cooling passages are formed within the blade, the cooling passages comprising a plurality of inlet passages along which cooling air flows from the base towards the tip region of the blade and a plurality of return passages along which cooling air flows from the tip towards the base region of the blade. At least some of the passages are connected by a common chamber located within the tip region of the blade.

Abstract: A method of diffusion bonding three metal work pieces to form a fan blade, where each workpiece has a flat surface and an excess portion larger than a predetermined size needed to produce a finished fan blade; longitudinally extending slots are provided to interconnect the flat surfaces of the excess portions of the work pieces; the work pieces are assembled into a stack with the flat surfaces in mating abutment and the stack is evacuated from one end of the stack through the slots; heat and pressure are applied across the thickness of the work pieces to diffusion bond the work pieces together to form an integral structure; the excess portions with the slots are then removed.

Abstract: A method of laser drilling a workpiece, the said method comprising directing a laser beam at the surface of a workpiece to be drilled by the laser beam; directing a jet of assist gas towards the point of incidence of the laser beam on the workpiece; characterised in that the said jet of assist gas is directed towards the workpiece at an angle with respect to the laser beam.

Abstract: A welding torch (10) comprises an electrode (12), means to supply weld filler material (14), a nozzle (16) surrounding the electrode (12), means to supply inert gas (17) to the nozzle (16) and a shroud (18) surrounding the nozzle (16). There are means to form a seal (20) provided between the nozzle (16) and the shroud (18), the means to form a seal (20) is arranged to allow relative movement between the nozzle (16) and the shroud (18). The means to form a seal (20) comprises a plurality of rings (22,24,26). Each ring (22,24,26) has an aperture (28,30,32) and an outer diameter (34,36,38). The diameter of the aperture (28) in a first ring (22) is substantially the same as the diameter of the nozzle (16). The outer diameter (34) of the first ring (22) is less than the outer diameter (36) of a second ring (24). The outer diameter (36) of the second ring (24) is substantially the same as the diameter of the shroud (18).

Abstract: An inverted ?-shaped clip (10) comprises first and second C-shaped clamping members (12,14) interconnected by an interconnecting member (16). The interconnecting member (16) has attachment means (22) whereby the inverted ?-shaped clip (10) is rotatable between a first position in which the attachment means (22) of the inverted ?-shaped clip (10) is insertable and/or removable from an aperture (42) in a support member (40) and a second position in which the attachment means (22) of the inverted ?-shaped clip (10) is secured in the aperture (42) in the support member (40).

Abstract: A gas turbine engine (10) comprises a first compressor (16), a combustor (22) and a first turbine (24) arranged in flow series. The first turbine (24) is arranged to drive the first compressor (16). The first compressor (16) has variable inlet guide vanes (38) and the first turbine (24) has variable inlet guide vanes (42). A second compressor (48) is arranged upstream of the first compressor (16). An auxiliary intake (12) is arranged upstream of the first compressor (16) and downstream of the second compressor (48). A valve (54) is arranged upstream of the first compressor (16) and downstream of the second compressor (48). The valve (54) is movable between a first position in which the second compressor (48) supplies air to the first compressor (16) and a second position in which the second compressor (48) does not supply fluid to the second compressor (16) and the auxiliary intake (12) supplies fluid to the first compressor (16).

Abstract: A turbine blade tip clearance control system has a rigid two part outer casing (42) which sandwiches a control ring (48) therebetween, and an air pressurised flexible inner casing (28) which carries shroud segments (22) within it. Struts (40) span the annular space between the casings (42, 28) and prevent flexing of casing (28) until blade tip clearance needs adjusting, whereupon, ring (48) is heated, along with the adjacent portion of outer casing (42) and expands, allowing casing (28) to flex outwards, thus lifting the shroud segments (22) away from the blade tips (24). Closure of the tip clearance is achieved by cooling ring (48), the resulting contraction thereof, via the struts (40), flexing the inner casing (28) and shroud segments (22) inwards, against the air pressure.

Abstract: An irreversible temperature indicating paint comprises 29 wt % to 37 wt % cobalt chromite spinel, alumina, gold purple and frit, 35 wt % to 45 wt % acrylic resin and 20 wt % to 30 wt % silicone resin excluding solvent. The solvent comprises a mixture of 80% 1-methoxy-2-propanol and 20% dipropylene glycol monomethyl ether. A particular irreversible temperature indicating paint comprises 34.9 wt % cobalt chromite spinel, alumina, gold purple and frit, 42.5 wt % acrylic resin and 22.6 wt % silicone resin excluding solvent. The irreversible temperature indicating paint has four or more colour changes in the temperature range 500° C. to 900° C. The irreversible temperature indicating paint is used to determine the temperatures to which various parts of turbine blades, turbine vanes or other component are subjected in operation of a gas turbine engine.

Abstract: A component such as a blade for use in a gas turbine engine comprises a body 2 formed from outer panels 8, 10 defining an internal cavity 12. A damping element 14 is provided in the cavity 12 and is secured at one end between the panels 8, 10 at one end of the body 2, for example adjacent the root of the blade. Damping material fills the cavity 12 and so extends between the damping element 14 and the panels 8, 10. Vibration induced in the blade causes relative movement between the body 2 of the blade and the damping element 14, causing energy loss in the damping material which damps the vibration. The components 8, 10, 14 may be secured by a diffusion bonding process.

Abstract: An irreversible temperature indicating paint comprises 29 wt % to 37 wt % cobalt aluminium spinel and glass, 35 wt % to 45 wt % acrylic resin and 20 wt % to 30 wt % silicone resin excluding solvent. The solvent comprises a mixture of 80% 1-methoxy-2-propanol and 20% dipropylene glycol monomethyl ether. A particular irreversible temperature indicating paint comprises 34.9 wt % cobalt aluminium spinel and glass, 42.5 wt % acrylic resin and 22.6 wt % silicone resin excluding solvent. The irreversible temperature indicating paint has four or more colour changes in the temperature range 500° C. to 900° C. The irreversible temperature indicating paint is used to determine the temperatures to which various parts of turbine blades, turbine vanes or other components are subjected in operation of the gas turbine engine.

Abstract: An indentor for contacting a bearing surface, the indentor comprising a contact surface complimentary to that of the bearing surface, wherein the indentor comprises an integral tapering portion which tapering portion defines part of the contact surface, the tapering portion at its distal edge defining an edge of contact between the contact surface and the bearing surface.

Abstract: A fuel delivery system for a gas turbine engine combustor, the combustor having at least two fuel injectors of substantially the same design. All the fuel injectors are in flow communication with a first fuel supply via a first manifold, and some but not all of the injectors are in flow communication with a second fuel supply via a second manifold. During normal operation of the gas turbine engine combustor fuel is supplied to all of the fuel injectors via the first manifold. However, during predetermined engine operating conditions a second fuel supply is used to supply fuel flow in those fuel injectors in flow communication with the second manifold.

Abstract: A wall element for use as part of an inner wall of a gas turbine engine combustor wall structure is of cast construction and includes a plurality of cooling apertures provided therethrough and formed during the casting process. The cooling apertures may be located in positions where they could not be conventionally formed by laser drilling.