Abstract: A DC electrical power system has a power generator converter system, a positive supply rail extending from the converter system, a negative supply rail extending from the converter system, and a midpoint earthing arrangement operatively connecting to the supply rails. The earthing arrangement is connected to earth by a solid earth connection. The network further has a first protective device on one of the supply rails which in case of a fault is operable to interrupt current flowing on that rail, and a second protective device on the earthing arrangement which in case of a fault is operable to interrupt current flowing to earth through the solid earth connection.

Abstract: A gas turbine engine has in flow series a compressor section, a combustor, and a turbine section. The engine includes a turbine section rotor disc, and a stationary wall forward of a front face or rearward of a rear face of the rotor disc. The wall defines a cavity between the stationary wall and the rotor disc, and has a plurality of air entry nozzles through which cooling air can be delivered into the cavity at an inlet swirl angle. The engine further includes a cooling air supply arrangement which accepts a flow of compressed air and supplies the compressed air to the nozzles for delivery into the cavity. The cooling air supply arrangement and the nozzles are configured such that the inlet swirl angle of the air delivered into the cavity can be varied between a first inlet swirl angle and a second inlet swirl angle.

Abstract: A method of compressing a gas, which uses a compressor train having a plurality of discrete portions and including at least an upstream portion, a mid-stream portion and a downstream portion arranged successively in flow series. The method includes: (i) performing a first compression step by directing a flow of said gas into the upstream compressor portion and driving the upstream compressor portion to compress the gas; (ii) performing a second compression step by directing the compressed flow from the upstream compressor portion into the mid-stream compressor portion and driving the mid-stream compressor portion to further compress the gas; and (iii) performing a third compression step by directing the compressed flow from the mid-stream compressor portion into the downstream compressor portion and driving the downstream compressor portion to further compress the gas.

Abstract: An igniter arranged to ignite combustion in a primary flow including a fuel and air mixture, the igniter including one or more geometric features arranged to: induce a shockwave flow structure at least partially disposed in the primary flow; and ignite the fuel and air mixture by virtue of the shockwave flow structure. The present disclosure also relates to a method of igniting combustion in a primary flow including a fuel and air mixture, the method including: providing one or more geometric features arranged to induce a shockwave flow structure; inducing the shockwave flow structure at least partially in the primary flow; and igniting the fuel and air mixture by virtue of the shockwave flow structure.

Abstract: A cowl cavity is defined between a core engine cowl and an engine inner casing. A core fairing is provided at the forward end of the engine inner casing and has a radially outer surface which, with the cowl, provides an airwashed surface of a bypass duct. A plenum is provided within the cowl cavity and receives air from bypass flow through openings in the surface. Conduits extend from a partition defining the plenum to distribute air to locations and components within the engine.

Abstract: A repaired composite material component 24 comprises parent composite material 12, a primary region 14 of replacement composite material and a secondary region 26 of replacement composite material which has a greater tendency to debond under loading of the repaired composite material component 24 than the primary region 14.

Abstract: A component, such as a turbine blade of a gas turbine engine, has an internal cooling system which includes a passage (28) having a passage inlet (22) and a passage exit (30), which may be in the form of passageways at or adjacent to the trailing edge of the component. The passage (28) is divided into chambers (52, 54, 56, 58) by partitions (40, 42, 44) which extend from one wall (34) of the component and terminate short of the opposite wall (36) to provide gaps (46, 48, 50) to permit chord-wise cooling air flow from the passage inlet (22) to the passage exit (30). The gaps (46, 48, 50) force the cooling air to pass adjacent the hot walls (34, 36), so increasing the heat transfer coefficient between the cooling air and the material of the component.

Abstract: A method of removing a deposit from a passage extending through a component includes immersing the passage within a liquid, and directing a liquid jet at the passage from a source within the liquid bath and with a sufficient velocity so as to remove at least a portion of the deposit.

Abstract: A method of controlling blade pitch angle, including comparing demanded and measured blade pitch angle and calculating any difference therebetween, in a primary electrical control system, where there is a difference, applying torque to a blade pitch regulator to reduce the magnitude of the difference to zero, and in a secondary electrical control system, where the difference is greater than a pre-determined threshold, applying torque to a blade pitch regulator to reduce the magnitude of the difference to the threshold. Also an electrical system of blade pitch angle control for a set of blades including primary and secondary electrical control systems, means for comparing demanded and measured blade pitch angle and calculating any difference therebetween, a look-up function having the difference as its input and outputting a required torque, and a torque regulator to apply the required torque to the set of blades.

Abstract: A turbomachine casing assembly including: a first casing element arrangeable adjacent to one or more rotating aerofoil structures of a turbomachine; a second casing element provided at a radially outer position with respect to the first casing element; and an infill member disposed between the first and second casing elements, wherein an end of the infill member is set back from an end of the first casing element such that a void is provided between the first and second casing elements.

Abstract: A halving joint structure including: a first member and a second member couplable to one another in a nonparallel arrangement by a halving joint, wherein each of the first and second members has a joint slot for receiving a portion of the other of the first and second members to form the halving joint; wherein the first and second members have cooperating locking slots, the locking slot of the first member intersecting the joint slot of the first member, and the locking slot of the second member being formed in the portion of the second member which is received by the joint slot of the first member; the structure further including: a locking member which is receivable within the locking slots of the first and second members.

Abstract: A safety connector (2) comprising: a first member (4) and a second member (6) movably coupled to one another; wherein the first and/or second members (4, 6) comprise a retention mechanism (14a, 14b, 16); wherein the retention mechanism (14a, 14b, 16) has a first configuration which prevents relative movement between the first and second members (4, 6) and a second configuration which allows relative movement between the first and second members (4, 6); and wherein the retention mechanism (14a, 14b, 16) changes from the first configuration to the second configuration when a force between the first and second members (4, 6) exceeds a predetermined threshold force.

Abstract: A halving joint structure comprising: a first member (2) and a second member (4) couplable to one another in a nonparallel arrangement by a halving joint, wherein each of the first and second members (2, 4) has a slot (6a, 6b) for receiving a portion (27, 29) of the other of the first and second members (2, 4) to form the halving joint; wherein the first and/or second member (2, 4) has a locking mechanism (14), the locking mechanism (14) being movable between an open configuration, which allows the portion (27, 29) of the other of the first and second members (2, 4) to be removed from the slot (6a, 6b), and a locked configuration, which prevents the portion (27, 29) from being removed from the slot (6a, 6b).

Abstract: A turbomachine casing assembly including a first casing element locatable radially outward of one or more rotating aerofoil elements of a turbomachine, a second casing element located radially distal to the first casing element is provided. A void is provided between a radially proximal face of the first casing element and a radially proximal face of the second casing element, at the first end of the first casing element. The first end of the first casing element is located against a corresponding first end of the second casing element by an energy absorbing element, with the first casing element; including a cantilever. The cantilever is arranged in a region extending along the first casing element from the first end; and having a pivot axis at a mid portion thereof.

Abstract: A method and apparatus (2) for masking a portion (36) of a component (30), the apparatus (2) comprising: a sacrificial masking element (4) for masking the portion (36); and a locating jig (6) detachably connectable to the sacrificial masking element (4) and configured to position the sacrificial masking element (4) over the portion (36) of the component (30).

Abstract: A workpiece support, including: first and second arms pivotably connected to first and second support members respectively, the first and second support members being spaced apart, each arm including first and second receiving members for receiving the workpiece, the first and second receiving members being provided at first and second ends of each arm respectively, wherein each arm is pivotably connected to the respective first and second support members at a point between the first and second ends of each arm, such that a workpiece may be supported by the first and second receiving members of the first arm and the first and second receiving members of the second arm.

Abstract: A nozzle guide vane arrangement comprising a vane member having a platform portion extending forwards of a leading edge of the vane member, the platform portion having a first securing member and a second securing member to provide at least part of the means to retain the vane member in use, the arrangement characterized in that the first securing member and the second securing member are staggered with an axial displacement relative to each other upon the platform portion in the direction from the leading edge to a trailing edge of the vane member.

Abstract: A wall element for a combustion space, the wall element comprising a ceramic body, a support within the body, and attachment means extending from the support and protruding from the body for securing the ceramic body to a combustion space wall.

Abstract: Fibre substrates act as a conduit for light along which response signals are transmitted to a controller in the form of an electronic device associated with a component. The processed signals are stored in a local memory to provide a component history and a prediction of future performance and life. Service and repair history may be added to the component device memory to enable a complete history to be stored with the component. A controller may transmit data to an external controller or display through typically a wireless connection. Power to the component electronics may be provided by an induction loop or transformer.

Abstract: Peening provides compression of component surfaces in order to create residual surface compressions to resist crack propagation in components such as aerofoils. Previously peening techniques have had problems with respect to achieving adequate treatment depths, speed of treatment and with respect to effectiveness. By the present method arrangement an electrical conductor in the form of a wire is subject to electrical pulses to cause evaporation and subsequent breakdown with high power ultrasound (HPU) propagation in a volume of dielectric fluid towards a component and so peening. The electrical conductor ensures that there is limited possibility of electrical discharge to the component surface while the positioning of the wire relative to the surface can be adjusted to achieve best effect particularly if reflector devices are utilized to concentrate (HPU) pulse presentation to the component.