Abstract: An electrical network for an aircraft. The aircraft includes at least one variable pitch propulsor. The electrical network includes a wound field synchronous AC electrical generator having a wound rotor driven by an internal combustion engine. The network further includes a voltage regulator configured to regulate output voltage of the electrical generator by regulating rotor winding magnetic field strength, and a synchronous AC drive motor coupled to a respective variable pitch propulsor and provided with power from the output of the electrical generator.

Abstract: A method of calibrating a sensor array having elements spaced from one another in a first direction, the array defining an array spatial response function, includes: providing a test workpiece having at least first and second calibrated defects spaced apart in the first direction by a characteristic distance such that when the first calibrated surface defect is located at a position corresponding to an array response function maximum, the second calibrated surface defect is located at a position corresponding to an array response function minimum; passing the array across the first and second calibrated surface defects in a direction normal to the first direction and determining a peak sensor signal from at least two of the elements in the array to determine an array spatial response function root mean squared average; and setting a rejection threshold as a predetermined proportion of the array spatial response function root mean squared average.

Abstract: A method of determining a faulty sensor of a sensor array of a gas turbine engine, the sensor array including at least first, second and third sensors, the method including the steps of: measuring a first set of sensor outputs prior to engine startup from each sensor, and calculating a first difference in the measured value for each sensor pair; after a period of time, measuring a second set of sensor outputs prior to engine startup from each sensor, and calculating a second difference in measured value for each sensor pair; calculating a further difference between the calculated first and second differences for each sensor pair; and identifying a failed sensor where two or more sensor pairs including a common sensor have a further difference above a predetermined threshold.

Abstract: A gas turbine engine nacelle comprising an intake liner. The liner includes a plurality of cells. Each cell includes an open radially inner end in fluid communication with an interior side of the nacelle, and an open radially outer end in fluid communication with an exterior side of the nacelle. Each open end of each cell defines a respective cross sectional area. The intake liner further comprises radially inner and outer facing sheets overlying a respective radially inner and outer open ends of the respective cell. Each facing sheet defines at least one aperture overlying at least one cell, an overlying portion of the respective aperture having a smaller cross sectional area than the respective open end of the respective cell.

Abstract: A gas turbine engine comprises a gearbox including a first epicyclic gearbox and a second epicyclic gearbox. The first epicyclic gearbox comprises a first sun gear meshing with the first planet gears and the first planet gears meshing with a first annulus gear. The second epicyclic gearbox comprises a second sun gear meshing with the second planet gears and the second planet gears meshing with a second annulus gear. An input shaft is arranged to drive the first sun gear and a first planet gear carrier is arranged to drive a propulsor. The first and second annulus gears are fixed to a static structure. A first clutch is arranged between the first planet gear carrier and the second planet gear carrier and a second clutch is arranged between the second sun gear and the input shaft. The gearbox is more efficient at cruise conditions.

Abstract: Method of determining an oxygen level inside a gas shield: providing a surface; positioning a gas shield over a portion of the surface; applying a pressure sensitive paint to the portion of the surface; flowing oxygen through the gas shield onto the portion of the surface; illuminating the portion of the surface; measuring a first fluorescent emission from the portion of the surface while oxygen is flowing through the gas shield; determining an oxygen saturation level across the portion of the surface in dependence on the magnitude of the first fluorescent emission; flowing a shield gas through the gas shield; illuminating the portion of the surface; measuring a second fluorescent emission from the portion of the surface while the shield gas is flowing through the gas shield; and determining an oxygen level across the portion of the surface in dependence on the relative magnitudes of first and second fluorescent emission.

Abstract: A fan track liner assembly for ducted fan engine which provides for reduced strain and deformation of front of fan case in the event of a fan blade off event. Various assemblies are proposed. In one aspect, assembly includes fan track liner panel and plurality of fasteners which are arranged to secure panel to fan case of engine, wherein: a forward portion of panel includes hinged portion which operates as trapdoor to permit blade or blade fragment to pass through, and fasteners are arranged to fail in the event of blade or blade fragment passing through trapdoor causing panel to be displaced rearwards in fan case. Other aspects provide for reduced height of support on fan case for attaching fan track liner and for collapsible comb box.

Abstract: A bladed rotor arrangement comprises a rotor, a plurality of rotor blades and a plurality of lock plates. The rotor blades are mounted in circumferentially spaced axially extending slots in the periphery of the rotor. A plurality of lock plates are arranged at a first axial end of the rotor and a plurality of lock plates are arranged at a second axial end of the rotor. The radially outer ends of the lock plates engage corresponding grooves defined by radially inwardly extending flanges on the platforms of the rotor blades. The radially inner ends of the lock plates also engage circumferentially extending grooves. The radially inner end of each lock plate has three crushable, deformable, circumferentially spaced feet to reduce the risk of the lock plates chocking against the rotor, or seal plates and additional radial loads being reacted by the rotor blades into the rotor.

Abstract: The valve includes a casing arrangeable so the fluid in the passage flows over an outer side. The valve includes a piston axially slidably positionable within the casing, and the axial position regulates the fluid pressure in the poppet valve passage downstream, an annular clearance between the piston and casing. The valve includes a dynamic seal between the piston and casing to seal the annular clearance end. The valve includes a piston chamber located on the dynamic seal opposing side of the annular clearance so a leakage flow may cross the dynamic seal between the annular clearance and piston chamber. The fluid pressure in the piston chamber varies the axial position within the casing. A diversion path formed in the casing diverts fluid for the leakage flow into the annular clearance from the fluid flow in the passage, the diversion path having filter to filter debris from the diverted fluid.

Abstract: The present invention provides a casting/hot forging die having a forming surface and an opposing rear surface. The rear surface has a plurality of cavities spaced by a plurality of walls. Each of the plurality of walls has a substantially equal width. At least one transverse wall may also be provided such that the walls define a grid spacing a series of rectangular or triangular cavities.

Abstract: A sensor system includes a sensor and a mast on which the sensor is mounted. The mast includes a core body and a shroud, wherein the shroud is provided about the core body, and the shroud is independently rotatable with respect to the core body under the influence, in use, of a fluid flow flowing past the shroud. The shroud is shaped so that, from at least one fluid flow direction, the shroud presents a different flow resistance in dependence upon the rotational orientation of the shroud. The rotational orientation of the shroud adjusts to reduce the flow resistance produced by the shroud to the fluid flow in response to the commencement of, or a change in the fluid flow direction to, one of the at least one fluid flow direction.

Abstract: There is disclosed a method of fabricating a composite structure (6). The method comprises the steps of: providing a pair of preforms (1, 2), each comprising a plurality of reinforcing fibers (3); providing an intermediate layer (4) of resiliently deformable material between said preforms (1,2) to space said preforms apart from one another such that each preform (1,2) bears against a respective side (5) of the intermediate layer (4); providing a curable matrix material around said fibers (3); and curing said matrix material to form said plastic composite structure (6). Also disclosed is a composite structure (6) having at least two layers of fiber-reinforced plastic (1,2) which are bonded to respective sides (5) of an intermediate layer (4) of resiliently deformable material, the intermediate layer (4) being arranged to space the two layers of fiber-reinforced plastic (1,2) from one another.

Abstract: A method of manufacturing a vane arrangement for a gas turbine engine comprises providing an aerofoil having a hollow cavity with an open end and providing a support member having a stub. The method further comprises welding the aerofoil to the stub. The method yet further comprises removing material from the stub so as to define a hollow region that extends through the support member and stub to the cavity of the aerofoil.

Abstract: A shaft (21) for use as a rotating shaft in a gas turbine engine has an axis (X), an outer surface, an inner surface (28), an upstream end and a downstream end. The shaft (21) is arranged, in use, to rotate in a circumferential direction (R) about the axis (X). The inner surface (28) includes a radially inwardly protruding flange (22), a circumferential array of radially extending apertures (26) provided in the flange (22) and an array of channels (24) extending from an upstream side to a downstream side of the flange (22). The channels arranged circumferentially between adjacent apertures (26) of the circumferential array of apertures (26).

Abstract: A stainless steel alloy comprising essentially 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 4.5 to 5.75 percent by weight silicon, 0.8 to 2.2 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 1.2 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 0.0 to 9.0 percent by weight niobium, 0.005 to 0.6 percent by weight titanium, 0.3 to 6.0 percent by weight molybdenum, and the balance iron plus impurities.

Abstract: A method of manufacturing a vane arrangement for a gas turbine engine comprises providing an aerofoil having a hollow cavity with an open end and providing a support member having a stub with a through hole extending therethrough. The method comprises welding the aerofoil to the stub such that the open end of the hollow cavity of the aerofoil is aligned with the through hole of the stub so as to define a hollow region extending through the support member and stub to the cavity of the aerofoil. During welding a tool is positioned within the through hole and cavity and is aligned with an interface between the stub and aerofoil, the tool being configured to prevent weld splatter onto a surface of the cavity or through hole.

Abstract: Electrical machine apparatus comprising: an elongate electrical conductor comprising a first part defining a first end and a second end, the first part defining a first conduit and a second conduit; a first coolant manifold arranged to provide coolant to the first conduit; and a second coolant manifold arranged to provide coolant to the second conduit.

Abstract: A method is provided of bonding a first component to a second component. The method includes: locating the first component against the second component to form an interface between the components, a curable adhesive being provided at the interface; locating a pressurizable, fluid-filled bladder against the first component such that the first component is sandwiched between the second component and the bladder; locating a backing member against the bladder such that the bladder is sandwiched between the backing member and the first component; pressurizing the bladder such that a consolidating pressure is exerted by the bladder on the first component to conform the first component to the second component; and curing the adhesive while the first component is conformed to the second component by the consolidating pressure.

Abstract: A gas turbine engine rotor arrangement comprising at least one blade and a disc is disclosed. The blade extends radially outwards from the disc and is secured thereto by cooperating shank of the blade and recess of the disc. The shank comprises a bottom surface facing a base surface of the recess, the bottom surface having axially extending peripheral edges. The bottom surface is shaped so that when the engine rotor arrangement is in use, liquid in a cavity between the bottom surface and base surface, acted upon by an unbalanced force in the radially outward direction, is guided by the bottom surface to flow between and away from the axial edges.

Abstract: An engine includes circumferentially spaced turbine blades radially inward a casing and circumscribed by a carrier section having segments, each having a carrier wall radially inward the casing and radially outward the turbine blades. The wall has one or more portions facing the casing. At least one of the portions has one or more impingement apertures for air passage of a predetermined temperature from a feed source into impingement onto the casing. The segments are radially inward the casing and radially outward the turbine blades, with the portions of their respective walls facing the casing. A method of controlling the gas turbine engine turbine casing temperature includes: passing air of a predetermined temperature from a feed source through the apertures in the one or more portions and into impingement on the casing; and optionally exhausting the air impinged onto the casing from a space between the segment and the casing.