Abstract: A mounting system for mounting a blade to a rotor body includes a pitch control mechanism including an anchor and a pitch change rod extending radially outwardly from the anchor to join to a base of the blade. The anchor and the rod are rotatable about the longitudinal axis of the rod to vary the blade pitch. The pitch control mechanism further includes a torque-transmitting formation between the blade and the anchor such that pitch-varying torque can be transmitted to the blade through the torque-transmitting formation while allowing relative radial movement between the blade and the anchor. The system includes a primary bearing formation, which transmits blade centrifugal loads to the rotor body while accommodating variation of the blade pitch, and secondary bearing formation, which transmits pitch change mechanism centrifugal loads to the rotor body while accommodating rotation of the anchor and the rod during variation of the blade pitch.

Abstract: A gas turbine engine control system comprising a variable stator vane schedule for normal operation of the gas turbine engine. The system is configured to generate an arm signal indicating potential shaft break. Then the system is configured to alter the variable stator vane schedule to slew each variable stator vane to decrease the available surge margin in response to the arm signal. Or the system is configured to limit a response rate of a variable stator vane actuator in response to the arm signal. Or the system is configured to alter the variable stator vane schedule and limit the response rate of the actuator.

Abstract: A tip treatment bar and associated rotor casing structure, wherein the tip treatment bar includes a solid composite structure having a plurality of layers arranged therein so as to provide the bar with a directional stiffness characteristic. Such a layered composite arrangement can be used to tailor the vibration characteristics of the bar. The tip treatment bar and casing structure may be suited for mounting relative to a fan or compressor in a gas turbine engine.

Abstract: A method of forming an annular support structure for fastening a component of a gas turbine engine to a static part of the engine is provided. The support structure has a substantially frustoconical skin portion which, in use, extends inwardly from the static part. The support structure further has a flange portion which extends inwardly from an inner edge of the skin portion. In use, a mating flange extending outwardly from the component is attached to the flange portion. The flange portion has an engagement face against which a corresponding face of the mating flange is secured. The flange portion further has an inwardly-facing land at an outer edge of the engagement face which restrains the component against radial movement.

Abstract: A bidirectional water turbine including: an upstream rotor and a downstream rotor, wherein the upstream rotor and downstream rotor are contra-rotating and each rotor includes a plurality of blade, the blades of the upstream and downstream rotors having substantially the same profile.

Abstract: An electrical generation system, including: a differential gearbox having an output drive, an input drive and a third drive which can be driven by or drive a load in use; a generator connected to and drivable by the output drive of the differential gearbox; a variable speed primary power source connected to the input drive of the differential gearbox; a regulating electrical machine which is operable as a motor and a generator connected to the third drive of the differential gearbox; at least one switch through which power is supplied to the electrical machine from the electrical output of the generator; and, a control system which monitors the electrical condition of the generator output.

Abstract: A blade assembly including: a hub which is rotatable about an axis; at least one blade having an aerofoil portion and a root, wherein the root is coupled to the hub using a primary retention device which prevents radial separation of the root and hub in normal use; and, a secondary retention device having a root part and a hub part, the root part being located radially inwards of the hub part in a retention cavity in use, wherein at least a portion of the root part enters the retention cavity via an interlock which prevents radial separation of the root and hub in the event of a primary retention device failure.

Abstract: Blade arrangements formed in a blisk configuration include a number of blades secured integrally or through welds or similar bonding to a rotor disc. The blades may be subject to vibration and it would be desirable to provide heat protection to junctions between the blades and the rotor. By providing insert elements between adjacent platform sections of a blade pair, vibrational damping as well as heat shielding and capability with regard to aerodynamic profiling is achieved.

Abstract: A composite blade (26) comprises a three-dimensional arrangement of reinforcing fibers (58) and a matrix material (60) infiltrated around the three-dimensional arrangement of woven reinforcing fibers (60). The three-dimensional arrangement of woven reinforcing fibers (58) defines a plurality of cavities (56) within the aerofoil (28). The composite blade (26) comprises an aerofoil portion (38) and a root portion (36). The aerofoil portion (38) comprises a leading edge (44), a trailing edge (46), a concave pressure surface wall (50), a convex suction surface wall (52) and a tip (48). The aerofoil portion (36) comprises a plurality of webs (54) extending between, and being secured to, the concave pressure surface wall (50) and the convex suction surface wall (52) to produce a Warren girder structure. The three-dimensional arrangement of woven reinforcing fibers (58) are arranged to produce the concave pressure surface wall (50), the convex suction surface wall (52) and the plurality of webs (54).

Abstract: A bleed flow discharge device (136) adapted to discharge a bleed fluid flow into a main fluid flow, wherein the bleed flow discharge device comprises an outer wall (135) defining a passage (137) for the bleed fluid flow, the outer wall comprising a wave-shaped edge (139) where the bleed fluid flow meets the main fluid flow.

Abstract: An annular flow mixer is provided for use in a gas turbine engine. A core generator of the engine provides an annular duct for the flow of working gas, which exhausts from the duct through the flow mixer. The flow mixer has a plurality of circumferentially spaced exhaust chutes from which the working gas exits in respective exhaust plumes. The exhaust chutes are configured such that, at the discharge end of the flow mixer, a radially outer portion of each exhaust chute radially overlaps with a radially inner portion of at least one adjacent exhaust chute.

Abstract: A datum line, such as the leading or trailing edge of an aerofoil component, is identified on a surface mesh of the component for use in a simulation. The method includes the steps of: defining a reference coordinate system including a direction X, which may be a general flow direction over the component; defining a span variable that varies along the component in a forwards marching direction, for example corresponding to the root to tip direction of the aerofoil; selecting a first frontal node on the datum line; using a Pareto front algorithm to define the datum line at an extremity of the surface mesh with respect to the X direction, the Pareto front algorithm evaluating a criterion for dominated nodes and operating on a Pareto variable to select successive connected frontal nodes that form the datum line.

Abstract: A vibration damping body including an auxetic cellular structure having cell walls therein formed substantially of a first material having a first stiffness, the cellular structure further including a second material attached to said cell walls, the second material being selectively located throughout the cellular structure so as to include less than 50% by mass thereof and having a second stiffness which is lower than said first stiffness.

Abstract: A bearing chamber apparatus (2) comprising a bearing chamber (4) having one or more seals (7) which seal an interior (5) of the chamber from an exterior (24) of the chamber; and further comprising: a pump in fluid communication with the interior of the chamber; and a controllable valve (20) in fluid communication with the interior of the chamber and the outside atmosphere. The arrangement allows oil leakage from the bearing chamber to be prevented and also allows a minimum pressure to be maintained within the bearing chamber.

Abstract: A method of analysing blade displacements detected by circumferentially spaced stationary timing probes associated with an assembly of rotating blades mounted on a rotor, including (a) identifying a possible resonant vibration event in the assembly of rotating blades; (b) zeroing the blade displacements on the rotations identified with the resonant vibration event to remove invariant blade displacements; (c) fitting modelled blade displacements corresponding to possible blade vibrational deflections at various frequencies to the zeroed blade displacements; and (d) characterising the resonant vibration event by identifying at each rotation the frequency having modelled blade displacements which correlate best with the zeroed blade displacements. Step (c) includes performing at each individual rotation the sub-step of fitting the modelled blade displacements at each frequency to the zeroed blade displacements for successive rotations which include that individual rotation.

Abstract: A fastener for securing together two sheet like members where a blind fixing is required, and yet possessing high positional accuracy. The fastener comprises a shank with a transverse foot the end of which carries a locating pin adapted to be received into locating holes in the members to be joined. The fastener is assembled by passing the foot through an opening in one of the members positioned so that the locating pin may be inserted into the locating holes. The fastener is secured by tightening a retaining nut and washer on a threaded portion of the shank of the fastener.

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 gas turbine engine has a nacelle, a plurality of pipes and a drains assembly, the drains assembly including a drains mast that extends through the nacelle and provides an outlet for the pipes. The engine is characterised in that drains assembly has a connection block defining internal passages and is arranged to connect between the pipes and the drains mast. The connection block also has lateral connections to the pipes enabling the nacelle to have a lower profile; thereby reducing aerodynamic drag.

Abstract: A biasing means is provided for securing a plurality of sealing components which are arranged to seal gaps between adjacent structural components in a turbine, the biasing means having three foot regions joined in a substantially linear fashion by two resilient curved arms, wherein each arm has securing means for securing the biasing means to one of said structural components such that when the biasing means is secured to said one of said structural components, each of said foot regions contacts one of said sealing components and the curved arms urge the sealing components towards one of said structural components so that the sealing components collectively create a seal over the gap between said structural components. An apparatus for sealing gaps between adjacent structural components which includes the biasing means is also provided as is a method of sealing gaps in a turbine.

Abstract: An apparatus for shaping an edge of an aerofoil comprising a brush and the brush comprises a plurality of bristles extending substantially parallel to each other. A motor rotates the brush about an axis. The axis is arranged substantially parallel to the bristles of the brush. A support structure holds the brush such that the axis intersects a first surface of the edge of the aerofoil or holds the brush such that the axis intersects a second surface of the edge of the aerofoil. There are means to move the brush such that the brush contacts the first surface of the edge or such that the brush contacts the second surface of the edge. There are means to produce relative movement of the brush and the aerofoil such that the first brush moves longitudinally along the edge of the aerofoil to shape the edge of the aerofoil.