Abstract: A pitch change apparatus is provided for a propeller assembly having a row of propeller blades which rotate around an axis of the assembly. The apparatus has a unison ring which is coaxial with the propeller assembly. The unison ring is movable to drive respective mechanisms for varying the pitch of the blades. The apparatus further has a plurality of pitch lock assemblies circumferentially distributed around the unison ring. Each pitch lock assembly has a free state which allows movement of the unison ring and a locked state which prevents or limits movement of the unison ring and thus prevents or limits variation of the pitch of the blades. The pitch lock assembly moves from the free to the locked state when the assembly receives a signal to lock the blades.

Abstract: An annulus filler assembly for a rotor of a turbomachine, the assembly comprising: an annulus lid (56) having a radially outwardly facing surface (58) for forming an inner wall of a flow annulus of the rotor and a radially inwardly facing surface; and a frame for supporting the annulus lid (40), the frame being mountable to a disc of the rotor such that the annulus lid (56) is spaced away from the disc, wherein the frame (40) comprises a connection portion (46) which, in use, passes through an aperture (60) in the annulus lid (56) from the radially inwardly facing surface towards the radially outwardly facing surface (58) such that at least a portion of the connection portion (46) is visible from the radially outwardly facing surface (58); the assembly further comprising a locking element (68) which locks the connection portion (46) to the annulus lid (56) via the visible portion of the connection portion (46).

Abstract: The present invention relates to an aerofoil having an erosion resistant leading edge. The aerofoil comprises an aerofoil main body portion and a leading edge portion. The leading edge portion comprises a plurality of functionally distinct parts, including at least; a first part for resisting abrasion of the leading edge portion, and a second part for resisting a bending force applied to the leading edge portion, and located behind the first part.

Abstract: A rigid electrical raft is provided to a gas turbine engine via a fusible mount arrangement. The rigid electrical raft may be a part of an electrical system of the gas turbine engine, for example a part of the electrical harness. The fusible mount is arranged to break when a predetermined load is applied. The rigid electrical raft may be attached to a fan case of the engine, and the predetermined load may that which results from a fan blade being released from the hub. This ensures that the rigid electrical raft is protected from the load.

Abstract: A seal segment is provided for a shroud ring of a rotor of a gas turbine engine. The seal segment is positioned, in use, radially adjacent the rotor. The seal segment has two or more spaced passageways. In use, a respective support bar can be contained within each passageway. The support bars allow attachment of the seal segment to the engine casing. Each passageway has an elliptical or substantially elliptical cross-section with a minor diameter and a major diameter, the minor diameter being substantially aligned with the radial direction. The respective support bar has a correspondingly elliptical or substantially elliptical cross-section for a close fit in the passageway.

Abstract: A seal segment is provided for a shroud ring of a rotor of a gas turbine engine. The seal segment is positioned, in use, radially adjacent the rotor. The seal segment includes a body portion having front and rear sides which each contain a respective slot that extends in the circumferential direction so that a respective hook formation is insertable into each slot for attaching the seal segment to the engine casing. The body portion is formed from continuous fibre reinforced ceramic matrix composite, reinforcing fibres of the composite wrapping around each slot so that, at the base of the slot, the reinforcing fibres are parallel to the surface of the body portion.

Abstract: The present invention relates to a flashback protector (1) for limiting the propagation of a flame towards a fuel supply. The flashback protector comprises a downstream side (34) and an upstream side (32) defining a flow path between them. A magnetic-field generator (10, 20) is arranged to generate a magnetic field (40) across the flow path such that when a flashback occurs fluid flows in the flow path towards the fuel supply through the magnetic field (40). This causes a flow of current (50) to be induced in the fluid. This results in a force being generated on the fluid away from the fuel supply, preventing the flashback from reaching the fuel supply and causing an explosion.

Abstract: A superconducting fault current limiter comprises a superconducting element having a plurality of superconducting portions and at least one connector. Each superconducting portion has end regions and each connector is connected to the end regions of adjacent superconducting portions to electrically and thermally connect adjacent superconducting portions of the superconducting fault current limiter together. Each connector provides a local reduction in the critical current and quench current of the end regions of the superconducting portions in contact with the at least one connector. This provides a phased transition of the superconducting fault current limiter in relation to the severity of a fault current.

Abstract: A turbine rotor assembly (32) comprising a turbine rotor (34) and a plurality of circumferentially spaced radially outwardly extending turbine rotor blades (36). The turbine rotor (34) has a rim (38) and a plurality of circumferentially spaced slots (40) provided in the rim (38) of the turbine rotor (34). Each turbine rotor blade (36) has a root (42) and the root (42) of each turbine rotor blade (36) is arranged in a corresponding one of the slots (40) in the rim (38) of the turbine rotor (34). Each of the slots (40) has a chocking device (50) and each chocking device (50) abuts a radially inner surface (52) of the slot (40) and each chocking device (50) abuts a radially inner surface (48) of the root (42) of the corresponding turbine rotor blade (36).

Abstract: An engine arrangement has a gear assembly that drives a first propeller assembly. The gear assembly is driven by a power drive shaft that joins to the gear assembly at a first side. The engine arrangement has a static conduit that extends along a longitudinal internal cavity of the power drive shaft. The conduit penetrates the gear assembly such that a portion of the conduit projects from an opposing second side of the gear assembly. The engine arrangement has one or more first fluid supply lines routed along the static conduit between a hydraulic pressure power source and the first hydraulic actuator. A first hydraulic rotating coupling is mounted to the projecting portion of the static conduit. The first fluid supply lines fluidly communicate with the first hydraulic actuator via the first rotating coupling.

Abstract: A fluid transfer arrangement comprising a duct having a first end and a second end, a pulse generation mechanism located at the first end of the duct to direct fluid pulses towards the second end of the duct in use, and a baffle located at the second end of the duct that defines an aperture having sharp edges. The sharp edges generate ring vortex fluid flow from the aperture in use. Applications include impingement heating and cooling.

Abstract: A method includes i) identifying a period of operation corresponding to a fuel supply requirement; ii) determining at least one ambient air condition in which the machine will operate during the period; iii) determining a duration of time in which, whilst in the ambient air condition, it is required to achieve a predetermined vapor trail characteristic; iv) determining a resultant fuel composition for use by the machine in the ambient air condition to achieve the characteristic, where the resultant fuel composition includes at least one of the first and second fuel compositions; v) determining the ratio of at least the first and second fuel compositions required for sufficient resultant fuel composition for the duration of time determined in step iii); and vi) producing a first signal indicative of the ratio of at least the first and second fuel compositions required for the duration of time determined in step iii).

Abstract: A turbine blade for a gas turbine engine has an aerofoil portion extending from a root to a tip. The tip carries winglets. A gutter extends across the tip to entrain gas leaking around the tip (over tip leakage). The aerofoil portion has a mean camber line and the gutter has a center line. In the examples described, the conditions that (a) the mean camber line and the centre line coincide at the exit when viewed from the tip towards the root, and (b) the mean camber line and the center line are parallel at the exit when viewed as aforesaid, are not both fulfilled.

Abstract: A process is provided for forming a leaf-spacer pair for use in a leaf seal which effects a seal between two components. The process includes the steps of: (a) providing a leaf section which maintains, in the leaf seal, wiping contact with one of the components, and a root section from which the leaf section extends and which, in the leaf seal, is fixed relative to the other component, the leaf section and the root section being formed from a first sheet of material of substantially uniform thickness; (b) providing a spacer formed from a second sheet of material, the spacer being physically separate from the leaf section and the root section; and (c) fastening the spacer to the root section to form a leaf-spacer pair in which the spacer overlays the root section and remains fixed relative thereto on handling of the leaf-spacer pair.

Abstract: A composite aerofoil vane for a gas turbine engine extends in use in a generally radial direction across an axially- and circumferentially-extending annular duct. The vane comprises a plurality of first reinforcing fibres extending in a generally radial direction and a plurality of second reinforcing fibres extending in generally axial and circumferential directions. The second fibres are interlaced with the first fibres so as to form a more unified and integrated structure, and to prevent the first reinforcing fibres from moving relative to one another.

Abstract: A method of zeroing displacement data derived from a rotor having an array of features monitored by an array of stationary timing probes. The method includes steps to calculate the displacement at each probe for each of at least two measured revolutions from time of arrival measurements. Each displacement is defined as a sum of a common term and a unique term. The set of displacements is solved for the common term and the unique terms. A probe offset is calculated from each unique term. The zeroed displacements are determined by subtracting the common term and probe offset from the calculated displacements for each probe.

Abstract: An assembly, for example in a gas turbine engine, includes a rotatable component supported by a bearing in a support structure. A sealing arrangement includes a non-rotating sealing ring which makes sealing contact with sealing features on the rotatable component. The non-rotating sealing ring is radially displaceable with respect to the support structure by means of ribs which engage axially facing support faces of the support structure. The non-rotating sealing ring is radially located by an outer, non-rotating, race of the bearing, by means of a locating surface on a locating body of the non-rotating sealing ring. As a result of this arrangement, the running clearance at the sealing arrangement can be maintained, despite radial displacement of the rotatable component with respect to the support structure, and despite thermal and mechanical deflections of the support structure.

Abstract: A protection system is provided for an electrical power network. The system has one or more circuit breaker arrangements which on activation isolate electrical faults within the network, and one or more fault detectors. The or each fault detector measures an inductance of a respective section of the network. The system is configured to activate one or more of the circuit breaker arrangements in response to measured inductances which are indicative of a fault.

Abstract: A fan blade (10) for a turbofan aero engine comprises a blade body including a root (10c) for engagement with a rotor, and a tip, wherein the tip is provided with a winglet (14).

Abstract: A method of manufacturing a hollow aerofoil component for a gas turbine engine includes using a capping panel to cover a pocket in a pocketed aerofoil body. During manufacture, the outer surface of the capping panel is located relative to the pocketed aerofoil body. This ensures that the outer surface of the capping panel is located as accurately as possible. This means that the capping panel can be made to be as thin as possible, which in turn reduces weight and material wastage. Once the capping panel has been located in position, it may be welded to the aerofoil body in order to produce the hollow aerofoil component.