Abstract: A turbine aerofoil for a gas turbine has a pressure wall and suction wall and at least one internal cavity. An aerofoil platform adjacent and generally perpendicular to the aerofoil has at least one internal cavity with a pressure wall and suction wall on respective sides of the cavity. The cavity is divided into at least two cooling chambers including a first chamber for receiving cooling air for the platform pressure wall and a second chamber for receiving cooling air for cooling the platform suction wall. The first chamber is in flow communication with the aerofoil cavity for discharge of at least part of the cooling air entering the first chamber to the aerofoil cavity.

Abstract: A gas turbine engine 10 includes an intermediate pressure compressor 14 connected to an intermediate pressure turbine 22 by a driveshaft 28. The driveshaft 28 comprises a downstream turbine shaft 34 attached to the intermediate pressure turbine 22 and an upstream compressor shaft 32 attached to the intermediate pressure compressor 14. The compressor shaft 32 and turbine shaft 34 are connected together by a splined connection 36 which allows the turbine shaft 34 to drive the compressor shaft 32. If the splined connected 36 should fail, so that it no longer transmits torque, a further splined connection 41 comes into operation to transmit torque between the turbine shaft 34 and compressor shaft 32. When this happens, torque is transmitted via a torsionally weakened, shear section 48 of the turbine shaft 34 which tends to break under certain engine conditions. The turbine shaft 34 is then released axially and turbine overspeed is restrained.

Abstract: A method of forming a body by deposition of a weld material comprises providing a welding head (12), providing a foundation (52) upon which the body is to be formed. A weld material is supplied from a supply (22). The welding head (12) and the foundation (52) are connected to a supply of electricity to form an arc between the welding head (12) and the foundation (52) to melt the material. A raised member (74) is provided on the foundation (52). The method further includes manipulating the foundation (52) and the welding head (12) relative to each other to deposit the material on the raised member (74) and form the body.

Abstract: A method of forming a hollow section body by deposition of a weld material includes the steps of providing a welding head 12 and a turntable 36 on which the body is to be formed, supplying a weld material to the welding head 12, the weld material to be deposited on the turntable 36 and connecting the turntable 36 and the welding head 12 to a supply of electricity to form an arc between the welding head 12 and the turntable 36 or the body to melt the material. The method includes the steps of manipulating the turntable 36 and the welding head 12 relative to one another to deposit material to form a first wall 40, manipulating the turntable 36 and the welding head 12 relative to one another to deposit material for form a second wall 42 extending from an angle to the first wall 40 and manipulating the turntable 36 and the welding head 12 relative to one another to deposit material to form a third wall 44 joining the first two walls, to form a hollow section body.

Abstract: A permanent magnet fault tolerant generator 32 is driven by a variable speed shaft 34 to create AC power at terminals 36, converted at 40 to DC power before being applied to a load 38. The converter 40 is a bi-directional device which rectifies AC to DC and also acts as an inverter to synthesize AC from the DC. This synthesized AC waveform is imposed on the terminals 36 to maintain a constant magnitude generator output voltage, regardless of the speed of the shaft 34, and thus regardless of the EMF of the generator. This results in reactive currents flowing between the generator 32 and the converter 40, but allows the generator design have a reduced current rating, resulting in improved generator size and weight.

Abstract: A method of manufacturing a through hole in a component between a first surface and a second surface, the through hole including a cavity formed in the first surface and a communicating passage between the second surface and the cavity including the steps of:

Abstract: A combustor for a gas turbine engine comprising a combustion chamber wall having formed therein at least one hole for admitting air into the combustion chamber and at least one air intake chute aligned with said hole. The air intake chutes are attached to the combustor wall in regions which, during operation, will be regions of low stress concentration.

Abstract: A nickel alloy composition, having particular utility for forming an oxidation resistant blade tip on a turbine blade, preferably has a composition substantially as defined by the nominal composition Cr 4.5 wt %; Al 6 wt %; Co 4 wt %; Ta 6 wt %; Re 4 wt %; Hf 0.15 wt %; C 0.05 wt %; Si 0.1 wt %; B 0.005 wt %; W 2 wt %; La 0.003-0.005 wt %; and Y 0 0.003 to 0.

Abstract: In a laser shock peening process, the shape of the spot 26 generated by the laser beam 4 is changed on the fly. This is achieved, for example, by a masking device 30 which is movable into and out of the path of the laser beam 4. Laser shock peening spots 24 can consequently be shaped so as to avoid the spots overlapping an edge of the workpiece, or any other feature which may be damaged by the laser energy.

Abstract: A disc component 2 for a gas turbine engine is produced from a workpiece 4 by a sequence of machining operations. During the machining operations, the workpiece 4 is supported by a fixture 36 engaging support surfaces 32, 34. The workpiece 4 remains secured to the fixture 36 throughout the sequence of machining operations so that these operations can be conducted on both faces 26, 28 of a disc portion 8 of the workpiece 4 without removing the workpiece 4 from the fixture 36. The machining operations are conducted alternately on the opposite faces 26, 28 in order to allow residual stresses in the workpiece 4 to dissipate in a controlled manner.

Abstract: A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle and a plurality of tabs which extend in a generally axial direction from a downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, where the tabs interact with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, where the tabs are substantially aerodynamically unobtrusive.

Abstract: A combustion chamber suitable for a gas turbine engine is provided with at least one Helmholtz resonator having a resonator cavity and a damping tube in flow communication with the chamber interior. The damping tube is provided with at least one cooling hole extending through its wall for improved damping and cooling.

Abstract: Methods for estimating performance of and/or detecting faults in components of a multi-component system, where the performance of each component is defined by one or more performance parameters x related to measurement parameters z that can be expressed as a function of the performance and operating parameters defining an operating condition of the system. The methods include: defining a series of fault classes corresponding to possible outcomes of faulty components; creating an initial population of strings for each fault class, each including a plurality of elements corresponding to the performance and operating parameters, values being assigned to the string elements which represent estimated values of said parameters and are constrained only to indicate fault affected values for performance parameters of the fault affected component of the respective class; and optimising an objective function which gives a measure of the consistency between measured and calculated values of the measurement parameters.

Abstract: A brush seal for sealing between a rotor and a stator of a gas turbine engine includes a housing and a plurality of flexible bristles held within the housing. The bristles protrude from the housing so that a free end of each bristle is able to contact and seal against a seal surface of the rotor. The brush seal further includes a stop member for limiting movement of the free ends of the bristles towards the seal surface of the rotor, in order to reduce wear on the bristles.

Abstract: An air cooled bearing comprising means for imparting a swirl component to the cooling air flowing toward the bearing. By imparting a swirl component to the cooling air the amount of work imparted on the cooling air by the rotating cage and rolling elements of the bearing can be reduced and in some cases substantially eliminated.

Abstract: Vane actuating apparatus for adjusting the angle of incidence of a set of variable angle vanes in a gas turbine engine comprises a plurality of vane actuator levers attached at one end to a respective vane and at the other end to actuation means for moving the vanes in unison. Each lever has an interlocking connection means for pivotally connecting the lever with respect to its respective vane in such a way that the lever is capable of being attached and detached from the vane at a first angular position, and retained in interlocking engagement for pivotal movement at a second angular position or range of positions.

Abstract: A gas turbine engine (10) fan outlet guide vane (34) is manufactured by diffusion bonding titanium alloy sheet metal workpieces (52, 54) together to form an in integral structure (66). A titanium alloy is weld deposited at predetermined positions (70, 72) and in a predetermined shape to build up bosses (42, 44) at the radially outer end (40) of the hollow integral structure (68). The integral structure (66) is inflated at high temperature to form a hollow integral structure (68) of predetermined aerofoil shape. Apertures (46, 48) are drilled through the bosses (42, 44) to enable the radially outer end (40) of the fan outlet guide vane (34) to be attached to a fan casing (32) of the gas turbine engine (10).

Abstract: A friction vibration damper for damping the vibrations of a vibrating component comprising a body, a chamber and a plurality of elements, the body defines the chamber which is partially filled with the plurality of elements, the friction vibration damper, in use, disposed on or in the vibrating component characterized in that the friction vibration damper is configured to substantially prevent the elements operationally moving in a convection-like flow pattern.

Abstract: A control system comprises: a plurality of input devices; a plurality of remote output devices; a plurality of dedicated connections and a digital data network interconnecting the plurality of input devices and the plurality of remote output devices. Each one of the plurality of output devices is connected to one of the plurality of input devices by an associated one of the plurality of dedicated connections. Each output device is operable to detect an addressing error in the digital network by comparing a value of a parameter received via its dedicated connection with the value of the same parameter received via the digital data network. Each output device is operable to use a network address dependent upon a value received via its dedicated connection.

Abstract: A gas turbine engine turbine section includes a turbine disk (20) which carries a stage of turbine blades (22). The turbine blades (22) have fir tree roots (24) which locate in fir tree grooves (26) in the rim of disk 20. Some of the projections that form the fir tree roots (24) of blades (22) and fir tree grooves (26) of disk (20) are truncated so as to define spaces between their truncated surfaces and the roots between adjacent overlapping projections, thus enabling the passing of a cooling air flow therethrough.