Abstract: An actuator arrangement for moving a first component relative to a second component, the arrangement comprising: an actuator chamber for receiving a fluid under pressure, a side wall of the chamber being fixed relative to the first component; an actuating element fixed relative to the second component and located inside the chamber for sliding movement along the chamber, relative to the side-wall; and a sealing element which provides a corresponding sliding seal between the actuating element and the sidewall for maintaining an actuating fluid pressure differential across the actuating element thereby to drive the actuating element relative to said side-wall, under said fluid pressure differential, for driving said relative movement of the first and second components; wherein the arrangement further comprises an external side-wall brace connected to the second component for corresponding movement with the actuating element along the outside of the sidewall, the brace being slidably or rollably braced against t

Abstract: A method of controlling a system that has a finite execution time in the optimisation of a cost function: J = ? i = 1 N ? F ? ( u ? ( k + i | k ) , y ? ( k + i | k ) ) , where N is selected such that J is convergent; k+i is the time in the future after the passage of i time increments; u(k+i|k) and y(k+i|k) are restricted to values of the respective control variables u and performance variables y that are compatible with predetermined system operational constraints; and for each time increment i=1 . . . N, values for F(u(k+i|k), y(k+i|k)) are calculated using a system model M to determine y(k+i|k) for a plurality of respective discrete values of u(k+i|k) that are limited to and representatively sampling the range of possible values of u that are compatible with the predetermined system operational constraints, J being optimised by identifying the combination {u(k+1|k),u(k+2|k), . . .

Abstract: A method of making an aerofoil blink comprising a plurality of aerofoil blades joined to a disc to extend radially outwardly therefrom is provided, The method includes the step of: (a) modelling a linear friction welding process in which a blade member is joined to the disc, the blade member having a stub for joining to the disc, wherein the modelling provides results which are indicative of the welding power at positions along the stub during the welding process; (b) identifying adaptations to the stub using the modelling results to compensate for differences in welding power along the stub during the welding process; (c) providing a blade member having a stub with the identified adaptations; and (d) joining the provided blade member to the disc by the linear friction welding process.

Abstract: A fan outlet guide vane for a gas turbine engine comprises a generally radially-extending internal structural member and at least one surface member securable in use to the internal structural member so as to define an aerofoil. The gas turbine engine includes an annular first structure and an annular second structure, the second structure being radially outward of the first structure so as to define a duct between them, and in use the internal structural member of the vane is secured between the first structure and the second structure. In a preferred embodiment, the surface member or surface members are secured only to the internal structural member, and not to the first or second structures.

Abstract: A turbomachinery disc, (e.g. a fan) has a primary axis of rotation and an axial flow direction X parallel to the primary axis of rotation. The disc has an annular diaphragm extending from proximate a blade land to a free inner radius. The diaphragm is asymmetrical about a plane (P) perpendicular to the primary axis of rotation.

Abstract: In order to provide simpler manufacture and lift up and blow down control, leaf elements are provided which have profile edges arranged to associate with each other in order to create a ring carousel, either about the front or rear edge of a leaf seal arrangement. In such circumstances gas flow through the leaf seal arrangement encounters the profile edge in order to adjust leaf section position for appropriate sealing efficiency.

Abstract: A method of mitigating the system-level effect of a fault detected in a vehicle system during a vehicle mission, the method comprising: using a processor to automatically prognose the system-level effect of said fault in terms of the residual capability of the vehicle system during the remainder of the mission, on the basis of predetermined stored data; using a processor to automatically generate a corresponding set of alternative reversionary or investigative action plans for mitigating said system-level effect during the remainder of the vehicle mission, on the basis of said prognosis; submitting the set of alternative reversionary action plans to a decision-making authority for determination by the decision-making authority of a preferred one of the reversionary action plans suitable for achieving a mission objective; and using a control unit, operably connected to the vehicle system, to implement the preferred reversionary action plan in accordance with said determination.

Abstract: An outer ring for a rolling element bearing has three mounting pads on its outer surface. The inner surface of the ring is arranged to be non-circular, with its effective radius being at a minimum at the three points midway between adjacent pairs of mounting pads. This provides a preload on the rolling elements of the bearing in use, preventing skidding, but because the ring is not supported between the pads it can still flex under loads. The ring may be oriented in use so that transient loads are directed through one of the mounting pads.

Abstract: A method for measuring the gap between a multibladed rotatable member and a surrounding housing in a gas turbine engine. In accordance with the method, a blade is removed from the rotatable member and replaced by a distance measuring clearance probe. The distance from the probe to the housing is then measured at a number of axial positions of the rotatable member.

Abstract: A gap 6 between a stationary component 2 and a rotating component 4 is sealed by means of a leaf seal comprising an array of leaves 8, 9. The leaves 8, 9 are disposed in pairs, comprising a higher curvature leaf 8 and a lower curvature leaf 9 which contact each other resiliently at their tips 12. The contact at the tips 12 provides a damping effect. As a result, the tips 12 of the leaves 8, 9 are relatively stable when subjected to an air flow F, enabling damaging flutter to be suppressed.

Abstract: A gas turbine engine (10) comprising a rotating member (16), a support structure (22) and a centering device (30), the centering device (30) centers the rotation of the rotating member (16) which is supported within the support structure (22), characterized in that the device includes a first member (34) and a second member (36) that contact one another, one of the first and second members (34, 36) extending from the rotating member and the other of the first and second members (34, 36) extending from the support structure (22), the first member (34) comprises a biasing surface (46) and the second member (36) comprises a seating surface (40), the device requiring a predetermined force to be applied to move between a centered condition and a first out of center condition and in the centered condition the first member (34) is seated against the seating surface (40) of the second member (36), and in the first out of center condition the first member contacts the biasing surface (46) which is arranged to provide

Abstract: A method is disclosed for controlling a process in which a component 4 is moved relative to another component 6 such that at least one of the components 4, 6 experiences a reduction in magnitude in at least one dimension. Such processes may include for example friction welding. The method comprises monitoring energy input to the process and adjusting an input parameter for the process based on the monitored energy input. The monitoring of energy input is performed before any reduction in component magnitude has begun to take place.

Abstract: A method of determining the quality of a friction weld between two components, the method comprising joining two components together using a friction welding process, measuring the loss of length of the components as a function of time during the friction welding process, determining the double differential with respect to time of the loss in length of the components as a function of time, determining the quality of the friction weld by calculating the R2 value of the linear fit to the loss in length of the components as a function of time over a defined time period, determining the end of the defined time period by identifying the start of the final positive peak of the double differential with respect to time of the loss of length of the components as a function of time, calculating R2 from the least square difference of the linear fit over the defined time period of the loss of length of the components as a function of time and comparing the calculated value of R2 with acceptable values of R2 to determine

Abstract: A drive mechanism comprising a first sprocket encircled by a tensioned chain and an orbit sprocket arranged to orbit the first sprocket in response to a resynchronisation signal. The orbit sprocket is arranged to displace the tensioned chain relative to the first sprocket. The first sprocket is rotatable and is coupled to an output drive sprocket by the tensioned chain such that the first and output drive sprockets are rotatable in synchronicity, whereby the orbit of the orbit sprocket alters the relative angular orientation of the first and output drive sprockets.

Abstract: A fuel distribution apparatus has a manifold head, a waisted portion and a nozzle head. An inlet channel is formed in a mounting surface of a casing of a jet engine. An annular inlet manifold is formed in the manifold head to receive fluid from the fuel inlet channel. Six outlet fluid passageways extend substantially tangentially away from the annular inlet manifold and open out into an annular outlet manifold. Three ports are formed in the inner wall of the annular outlet manifold and the ports are connected to fuel delivery tubes which extend away from the ports in a substantially helical fashion around the waisted portion into a nozzle head. The outlet fluid passageways are arranged to direct the fluid around the outlet manifold in a first direction and the helical fuel delivery tubes extend in the opposite direction.

Abstract: Dampers (56, 76, 96) are utilized with regard to mounting arrangements (50, 70, 90) in gas turbine engines (10) in order to facilitate cooling. It is known to provide slotted upper surface or cottage roof dampers to enhance cooling effect. However, cooling efficiency cannot be optimized and improving cooling effectiveness particularly between the parts of a mounting arrangement can be difficult without detrimental reductions in overall efficiency of a gas turbine engine (10) incorporating such a mounting. By provision of impingement jets (54, 75, 94) which extend through the damper (56, 76, 96) into slots (51, 71, 91) which define an upper surface of the damper (56, 76, 96) improvements in cooling efficiency can be achieved. The slots (51, 71 91) are typically closed to reduce requirements with respect to pressure differentials. However, open ended slots (51, 71, 91) with impingement jets (54, 74, 94) can also be provided.

Abstract: A rotor blade for a gas turbine engine, comprising an aerofoil having pressure and suction surfaces, leading and trailing edges, and an array of passages at a tip region of the aerofoil. The passages extend from the pressure surface to the suction surface of the aerofoil and are disposed so that the array creates, in operation, a planar jet of gas issuing from the suction surface. The jet is inclined outwardly from the suction surface and towards the tip, and in the direction from the leading edge to the trailing edge. The jet inhibits migration away from the suction surface of a clearance vortex formed by leakage of air over the tip of the rotor blade.

Abstract: A clamping assembly (2) adapted to clamp a component (4), the assembly comprising: first and second clamping members (10, 20), the first and second clamping members being movable with respect to one another in a first direction to selectively clamp the component therebetween; and a bearing element (30) positionable between the component and one of the first and second clamping members, the bearing element being configured to permit relative movement between the component and one of the first and second clamping members in a second direction.

Abstract: A split flow valve arrangement comprising a first valve portion having an inlet, a first outlet and a second outlet; and a second valve portion having a first inlet coupled to the first outlet, a second inlet coupled to the second outlet, a main outlet and a secondary outlet. The inlet is selectively coupled to none, one or both of the first and second outlets; the first inlet is selectively coupled to the main outlet and the second inlet is selectively coupled to the secondary outlet. The first and second valve portions are constrained to move in synchronicity to therefore selectively direct fluid to flow from the inlet to none, one or both of the main and secondary outlets.

Abstract: A method (40) of improving the mechanical properties of a component, for example a gas turbine engine turbine disc, (24) comprises isothermally forging (42) a preform to produce a shaped preform with a predetermined shape at a first predetermined temperature, solution heat treating (44) the shaped preform, quenching (46) the shaped preform, forging (48) the shaped preform at a second predetermined temperature to impart a predetermined residual strain in the shaped preform, ageing (50) the shaped preform and finally machining (52) the shaped preform to a finished shape. The second predetermined temperature is less than the first predetermined temperature.