Abstract: A magneto-plasma-dynamic (MPD) generator, comprising: a conveying duct shaped for conveying a high velocity, conductive fluid; a magnetic field generator arranged to generate a magnetic field across the conveying duct, substantially perpendicular to the direction of travel of the fluid, such that the fluid passes through the magnetic field (2) when conveyed by the duct; electrodes provided in the conveying duct to conduct a current induced in the fluid as it is conveyed by the conveying duct through the magnetic field; and an electrode supplying mechanism configured to supply a conductive liquid for replenishing the electrodes.

Abstract: A flow discharge device, such as a compressor bleed outlet discharging into a bypass duct of a gas turbine engine, comprises an outlet panel 46 which is perforated by openings 48, 50 disposed in an array which tapers in the downstream direction with respect to the flow B in the bypass duct. The configuration of the array of openings 48, 50 creates a plume 60 of tapering form, which enables the bypass flow B to come together downstream of the plume 60 with minimal wake generation, to provide a shield of cooler air so as to avoid contact between the hot gas plume 60 and a wall of 27 of the bypass duct 22. The resulting aerofoil-shaped cross section of the plume 60 also reduces any blocking effect in the bypass duct 22, with consequent performance benefits for the engine fan.

Abstract: A method of forming an internal structure in a hollow component that includes the steps of forming an assembly having first, second, and third plates the first and second plates each with a substantially planar surface and a surface that includes at least one protrusion and is on the exterior facing surfaces of the assembly. The third plate is sandwiched between the first and second plates. The method also includes the steps of selectively bonding portions of the third plate to sections of the first and second plates substantially opposite the at least one protrusions of the first and second plates; and forming the assembly against a die such that the at least one protrusions of the first and second plates are transferred from the exterior facing surfaces to the interior facing surfaces of the first and second plates.

Abstract: In a DC electrical power system used in an aircraft, an earthing arrangement is provided between electrical power supply rails in the form of a pair of capacitors with a mid electrical voltage earthing point, having an earthing path, in which electrical resistance is provided to limit electrical current flow and therefore allow continued operation despite the earth fault.

Abstract: There is disclosed an impingement cooling arrangement for a gas turbine engine (6), and an engine provided with such an arrangement. The cooling arrangement comprises at least part of a casing (21) configured to define a flowpath for the passage of hot gases through the engine, and a manifold (22) configured to direct cooling air against an outer surface (23) of the casing for impingement cooling thereof. The arrangement is characterised by said manifold (22) being configured to direct a primary flow of cooling air (65) against is a first area (64) of the casing outer surface (23) for impingement cooling of said first area, and to recirculate (66) at least a portion of said primary flow of cooling air after impingement against said first area (64) and to direct at least a portion of the recirculated flow against a second area (67) of the casing outer surface (23) for impingement cooling of said second area (67).

Abstract: Vibration damping is important with regard to such components as hollow turbine blades in gas turbine engines. Traditionally damping has occurred through damping elements secured at the root or tip of such blades. Such damping is not optimised and results in potential problems with wear in operational life. By providing a tube of deformable material which can be located within a hollow cavity it is possible to provide an element which through friction engagement can absorb vibration energy and therefore damp such vibration. The tube incorporates a number of cuts and/or grooves in an appropriate pattern in order to define a deformation profile once the tube is expanded in location. The tube is secured in position internally upon an expandable element which is typically an inflatable device. Once in position the tube is retained in its expanded deformable profile and the engagement between the tube and the hollow cavity wall surface results in energy absorption through vibration episodes.

Abstract: A turbine engine arrangement incorporates an electrical machine combination which can act as a generator or motor. Thus, the combination during initial turbine engine arrangement start-up acts through this motor to drive shaft rotation. This shaft rotation creates core compressed air which is bled through a valve to an air turbine such that the electrical machine when acting as a motor or generator at low engine loads is appropriately cooled. The arrangement also includes a compressor fan which generates an airflow utilised by the air turbine in order to drive the electrical machine as a generator of electrical power when engine conditions dictate. A duct is provided to direct airflow exhausted from the air turbine to a heat exchanger arranged to exchange heat with a bypass flow from the compressor fan.

Abstract: In order to achieve micro alloying of protective coatings for components such as turbine blades in a turbine engine, a base metal is splutter coated by deposition of a trace element to a desired proportion. A protective layer of the base metal is then applied over the trace element to prevent further reaction or oxidation of the trace elements. A coating consumable is therefore formed from the base metal and the trace element. The consumable may be produced immediately prior to coating of the component or may be inertly stored for subsequent use. The consumable is applied by laser deposition techniques whereby a coating is formed in the melting process.

Abstract: A turbomachine blade comprising a root portion and an aerofoil portion, the aerofoil portion having a leading edge, a trailing edge, a concave metal wall portion extending from the leading edge to the trailing edge and a convex metal wall portion extending from the leading edge to the trailing edge, the concave metal wall portion and the convex metal wall portion forming a continuous integral metal wall, the aerofoil portion having a hollow interior defined by at least one internal surface, the hollow interior of the aerofoil portion being at least partially filled with a vibration damping material that is separated from the metal wall portions by a thermally insulating material.

Abstract: An aerofoil blade for a gas turbine engine, the blade having a metallic core defining a number of cavities that contain a foamed material. The cavities are shaped such that the force of an impact on one surface of the blade is dissipated through the foam and transmitted to the metallic core. A fibrous internal containment device allows the blade to fragment progressively thereby spreading the load imparted by the blade to a casing should the blade fragment upon impact.

Abstract: A rotor such as a blisk B is balanced by determining the extent of any static or couple unbalance when the rotor is rotated about a test axis X while supported at a location surface 10 at which the rotor is supported in normal use. The location surface 10 is then modified, for example by removing material in a final machining operation, to eliminate the unbalance. For example the swash of the surface 10 may be altered and/or modification may be made to other location features (11) in order to cause the rotor to rotate, in normal operation, about an axis which is eccentric to the test axis X.

Abstract: A gas turbine engine comprising an intermediate compressor and two shafts connecting respective high and low pressure turbines and compressors respectively is characterised by the intermediate pressure compressor connecting to either the high pressure shaft or the low pressure shaft via a gearbox.

Abstract: A method of manufacturing an aerofoil structure capable of being diffusion bonded and superplastically formed to create a substantially hollow cavity within the aerofoil structure, the method comprising: providing a metallic plate for forming the aerofoil structure; joining mounting elements to opposing end surfaces of said metallic plate; dividing said plate along a plane extending substantially in a span-wise direction so as to produce two metallic panels each with one of said mounting elements joined thereto; assembling the two metallic panels so that the surfaces of the panels opposite to the surfaces which have been divided are facing each other; and joining the two metallic panels to one another to form the aerofoil structure; wherein the mounting elements are joined to one another to form the root of the aerofoil.

Abstract: A method of manufacturing an aerofoil structure capable of being diffusion bonded and superplastically formed to create a substantially hollow cavity within the aerofoil structure, the method comprising: providing two metallic panels (8, 10, 16); assembling and joining the two metallic panels (8, 10, 16) to one another to form the aerofoil structure; wherein the two metallic panels each comprise a surface (8, 10, 16) capable of forming an aerofoil and further comprise a root or section thereof (4, 14) which is either integral with or fixed to the aerofoil surface; and incorporating a section of a different material into a part, the said section being made from a material which is different from the material of another part of the aerofoil structure.

Abstract: A method of manufacturing a blade (20) for a turbomachine by superplastic forming and diffusion bonding a first layer (18), a second layer (16) and a membrane (2), the membrane (2) being disposed between the first and second layers (18, 16), the method comprising: applying a stop-off material in a first predetermined pattern between the first layer (18) and the membrane (2) so as to prevent a diffusion bond from forming between the first layer and the membrane across said first predetermined pattern; wherein the first pattern is applied such that it defines one or more first strips (12) and one or more first dots (15), the first strips and first dots being void of the stop-off material, and wherein the first strips are arranged in a span-wise direction, and the first dots are located between the first strips and the blade tip edge, the first dots (15) being offset from a longitudinal axis of the first strips (12) in a chord-wise direction; and applying the stop-off material in a second predetermined pattern b

Abstract: A system and method for variable drive of a propeller or fan of a gas turbine engine. The gas turbine engine has a combustor and a turbine arranged to be driven by a combustion product from the combustor. The variable drive system comprises a primary shaft arranged for transmission of torque from said turbine to the propeller; an electric generator arranged to be driven by said turbine; and an electric motor arranged to be driven by the output of said generator. A clutch is mounted between the propeller and the primary rotor and is operable to mechanically disconnect the shaft from the propeller so that the propeller can be driven by any or any combination of the turbine and/or electric motor. The invention may be applied to a turboprop or turbofan engine having a gearing between the shaft and propeller or fan and may be particularly suited to unmanned aerial vehicle propulsion.

Abstract: A shaft coupling device to couple first and second shafts, said device comprising a fluid coupling having a first portion attached to the first shaft and a second portion attached to the second shaft wherein the device further comprises engagement means operable to switch the device between an engaged position and a disengaged position, the engaged position having each of the first and second shafts engaged with its respective portion of the fluid coupling and the disengaged position having at least one of the first and second shafts disengaged from its respective portion of the fluid coupling.

Abstract: Two tubular components (10, 14) are provided with integral end caps (11, 15). The end caps (11, 15) are placed in abutting relationship and are held together under pressure whilst the tubular component (10) is rotated. A pressure is applied and this causes frictional heating. A friction welded joint (18) occurs at the interface between the two end caps (11, 15). On completion of the welding process a machining tool is then passed through the internal bore (12 or 16) in either of the tubular components. The machining tool cuts through the joined end caps (11, 15) to produce a single uniform bore thorough the joined components. In a further post processing operation the extruded flash (20) is removed from the outer surfaces (13, 17).

Abstract: The invention provides an arrangement for mounting a nose cone 32 on a gas turbine engine. The nose cone 32 has an inwardly tapering flange 64 which defines an inclined contact surface 68. A nose cone support ring 36, mounted in use to a flange 38 on the front of the fan disc 34, has an outer rim 42. An inwardly extending part 50 of the support ring 36 defines an inclined contact surface 54. A plurality of spaced radial openings 44 are provided through the rim 42 each having a countersunk opening 46. A fastening arrangement 70, associated in use with each opening 44, comprises a bolt 72 with a countersunk head. A Vee block 76 locates on each bolt 72, with a mounting nut 78 below it. In use, the nose cone 32 is brought up against the support ring 36. Appropriate rotation of the bolts 72 will cause the nuts 78 and hence Vee blocks 76 to move radially outwardly.

Abstract: A method of forming a structure by a material additive process, the method comprising the steps: providing a substrate having a surface, providing an interlayer on the surface which conforms to the surface of the substrate, forming a melt pool in the interlayer, the depth of the melt pool being less than the depth of the interlayer, selectively depositing a material within the melt pool, allowing the material to solidify, and applying heat and pressure to diffusion bond the material to the substrate.