Abstract: A variable geometry (2) structure comprising: an flexural element (4); a tensioning element (6) connected to the flexural element (8); and an actuator (12) for adjusting the tensioning element (6) to change the load placed on the flexural element (4), thereby changing the geometry of the structure (2).

Abstract: There is provided a liquid-capturing shaft (30). The shaft is hollow, arranged for rotation about its longitudinal axis (31), and has a cylindrical wall (32) defining an inner surface (33) and an outer surface (34) of the shaft and through which are formed a plurality of circumferentially spaced apart inlet openings (35). Each inlet opening (35) has a respective inwardly and axially facing capture surface (40) which extends from the outer surface (34) of the shaft to the inner surface (33) of the shaft.

Abstract: A low pressure shaft is provided for interconnecting a fan or low pressure compressor of a gas turbine engine with a low pressure turbine of the engine. The shaft has an aft section whose diameter expands progressively with distance along the rearward direction of the engine. The shaft further has an annular joint portion at the rear end of the aft section for joining the shaft to a drive arm of the low pressure turbine. The rate of expansion of the diameter of the aft section decreases with distance along the rearward direction of the engine.

Abstract: A leaf seal for effecting a seal between two, coaxial, relatively rotating components. The leaf seal has an annular pack of stacked leaves. The pack is mountable to a first one of the components with interleaf gaps formed between working portions of neighbouring leaves. The leaves extend towards the other component such that end edges of leaf working portions are presented for wiping contact with the other component. At least adjacent its end leaf edge, each leaf has a rear section at or adjacent the low pressure side of the pack and a front section which extends from the rear section to the high pressure side of the pack. The rear sections of the leaves are thicker than their respective front sections to reduce the interleaf gaps at the rear sections such that most of the pressure drop across the pack is over the rear sections.

Abstract: A method of controlling an inverter for converting a DC input to an AC output, the method including measuring a voltage of an AC output produced by the inverter; determining a drive voltage for controlling the inverter; and if a difference in amplitude and/or phase between the drive voltage and the measured voltage exceeds a predetermined threshold, modifying the drive voltage to reduce the difference in amplitude and/or phase between the drive voltage and the measured voltage. The method may be particularly useful for controlling an inverter during “islanded” operation with a variable load, and may therefore be useful e.g. in marine, battlefield, disaster relief and/or aviation electrical power systems.

Abstract: This invention relates to an aircraft comprising: a first propulsive unit having a first fan with an axis of rotation; and a second propulsive unit local to the first propulsive unit, the second propulsive unit having a second fan with an axis of rotation, wherein the rotational axis of the first fan is proximate to the surface of the aircraft relative to the rotational axis of the second fan such that the first fan ingests boundary layer air when in use.

Abstract: A method is described in which a composite tape or sheet is processed such that it has an improved drapability when applied to a former having a complex geometrical form. The tape or sheet is selectively perforated across its width as it is dispensed, with a suction force being subsequently applied over the tape's surface to thereby cause stretching of the tape. The degree of stretching varies across the width of the tape in proportion to the degree and local density of the selective perforations.

Abstract: A head part of an annular combustion chamber for a gas turbine, the head part comprising: an end wall with a passage opening for accommodating a burner, the end wall comprising a back side which faces towards the combustion chamber; a burner collar adapted to fit within the passage opening and receive the burner, the burner collar comprising a protruding portion radially protruding from an outer surface of the burner collar; and a ring member for receiving the protruding portion of the burner collar; wherein the head part of the annular combustion chamber is configured such that in an installed configuration a radially outer portion of the ring member engages with the end wall and a radially inner portion of the ring member receives the protruding portion of the burner collar.

Abstract: A gas turbine engine 10 is provided with rigid raft assemblies 290, which may be electrical harness raft assemblies 290 comprising electrical conductors embedded in a rigid composite material. The rigid raft assemblies 290 can be provided with engine dressings, such as pipework and ECUs to produce an electrical raft assembly. In order to assemble or dress the gas turbine engine 10, the rigid raft assemblies can be pre-prepared to incorporate at least a part of at least one gas turbine engine system/component before being installed on the gas turbine engine 10. During maintenance, whole raft assemblies can be removed and replaced with corresponding, pre-prepared assemblies. This can save considerable time during engine build and maintenance.

Abstract: A component such as a pressure vessel includes a cladding layer bonded to a substrate by a welding process. The component is inspected by a method that includes using a first camera to record a first image of an inspection portion of the cladding layer, the inspection portion having a pattern of markings; causing or allowing a temperature change in the component; using a second camera to record a second image of the inspection portion; and identifying the deformation of the pattern of markings on the inspection portion by reference to relative movement of the respective markings between the first and second image. The temperature change may occur as a result of cooling of the component after the welding process. Analysis of the deformation may be conducted by a Digital Image Correlation process, enabling possible defects or flaws in the component to be identified.

Abstract: A mechanism such as a rotor of an open rotor gas turbine engine comprises a rotor assembly 100 rotatable about a rotational axis A. The rotor assembly 100 has a fluid pathway 110 including a pump 114 carried by the first rotor assembly 100 for driving fluid along the fluid pathway 110. The fluid may be oil for lubricating components of the mechanism. The fluid is collected by an annular channel-shaped collector 111 and pumped through surface coolers 116 to an outlet pipe 119. From the pipe 119 the fluid migrates along a path 500 under centrifugal force, returning to the collector 111.

Abstract: A method of cold forming titanium alloy sheet metal, the titanium alloy consisting of 5.5 to 6.75 wt % aluminum, 3.5 to 4.5 wt % vanadium and the balance titanium plus incidental impurities, the method comprising the steps of (a) heat treating at 700° C. for at least 30 minutes and (b) cold forming at room temperature. Step (b) may comprise bending the titanium alloy sheet metal using a press brake. Step (b) may comprise placing a neoprene rubber film or a rubber film between the titanium alloy sheet metal and a lower V of the press brake. Step (b) may comprise placing the titanium alloy sheet metal into the press brake such that the grain of the titanium alloy sheet metal is arranged at an angle to the bend axis of the press brake. The method reduces and preferably overcomes cracking of the titanium alloy sheet metal during cold forming.

Abstract: A turbine engine includes an engine core bounded by a bypass duct, a first portion of the bypass duct defined by a fan casing having a radially inner wall and a radially outer wall, a second portion of the bypass duct defined by a radially inner wall and a radially outer wall, a third portion of the bypass duct provided as at least one access door comprising a flow guide structure; and a thrust reverser mechanism coupled to the fan casing.

Abstract: A gas turbine engine installation is provided that has a plurality of flexible printed circuit board (FPCB) harnesses to transfer electrical signals, including electrical power, around a gas turbine engine. The plurality of FPCB harnesses is held to the gas turbine engine installation using generally U-shaped clips that have a base from which first and second sidewalls extend. The FPCB harness is held between the tips of base-teeth extending from the base, and side-teeth extending from the first and second sidewalls. In this way, the FPCB harness can be held securely in position by the clip.

Abstract: A gas turbine engine has, in flow series, a compressor section, a combustor, and a turbine section. The gas turbine engine further has a system (i) for cooling the turbine section and (ii) for providing tip clearance control between turbine blades of the turbine section and a plurality of circumferentially distributed segments which form an annular shroud surrounding the outer tips of the turbine blades. The system includes a turbine section cooling sub-system which diverts a first cooling air flow received from the compressor section to a heat exchanger and then to the turbine section to cool components thereof. The first cooling air flow by-passes the combustor and is cooled in the heat exchanger. The turbine section cooling subsystem has a first valve arrangement which regulates the first cooling air flow. The system further includes a tip clearance control sub-system which supplies a second cooling air flow to an engine case to which the segments are mounted.

Abstract: A gas turbine engine has, in flow series, a compressor section, a combustor, and a turbine section. The engine further has a cooling system which diverts a cooling air flow received from the compressor section to a heat exchanger and then to the turbine section to cool a component thereof. The cooling air flow by-passes the combustor and is cooled in the heat exchanger. The cooling system has a valve arrangement which regulates the cooling air flow. The engine further has a closed-loop controller which estimates and/or measures one or more temperatures of the cooled component, compares values derived from the estimated and/or measured temperatures with one or more corresponding targets, and issues a demand signal to the valve arrangement based on the comparison and a value of the demand signal at a previous time step.

Abstract: A gas turbine engine stand comprising an engine frame and a base frame. The base frame has a slide rail to enable axial translation of the engine frame relative to the base frame. A load transfer arrangement engages with a part of the engine frame and slidingly engages with the slide rail. There is a locking mechanism to lock the engine frame to the base frame to prevent relative axial translation. The gas turbine engine stand is used, inter alia, for splitting a core engine from a fan case.

Abstract: A hot isostatic pressing tool comprises a canister and a support structure. The canister forming an annular chamber to receive a powder material to be hot isostatically pressed, the annular chamber having an annular portion having a predetermined radial dimension and at least one annular sub portion at a predetermined axial position having a radial dimension greater than the predetermined radial dimension. The support structure comprising at least one annular member arranged radially within the canister. The at least one annular member is located radially within the at least one annular sub portion of the annular chamber to support the canister at the predetermined axial position.

Abstract: A rigid electrical panel and a method of manufacturing a rigid electrical panel is provided with a fire protection layer on at least one side. The fire protection layer comprises fibers and an intumescent material. The rigid electrical panel comprises electrical conductors embedded in a rigid organic matrix composite. In the event of a fire, the fire protection layer protects the embedded electrical conductors, and any other features or components carried by the electrical panel.

Abstract: A method of linear friction welding, the method comprising: a friction phase comprising oscillating a first workpiece (2) relative to a second workpiece (4) with a surface of the first workpiece (2) being forced against a surface of the second workpiece (4), such that a plasticised layer is formed at the interface between the first and second workpieces (2, 4); wherein the friction phase is divided into a plurality of sub-phases, each sub-phase being configured to form a plasticized layer at the interface between the first and second workpieces (2, 4), each plasticized layer comprising a stagnation zone (10a, 10b); wherein the stagnation zone (10a) of one sub-phase is offset from the stagnation zone (10b) of another sub-phase.