Abstract: Flow restrictors (4), (14) are widely utilised with regard to providing flow control in such situations as with respect to sealing and pressurisation of bearing chambers in gas turbine engines. The restrictor (4), (14) restricts a flow (5), (15) but with prior arrangements may be susceptible to deposition upon flank surfaces of the restrictor (4). These depositions may fragment and block an aperture (7), (17) of the restrictor (4), (14) reducing operational effectiveness. By provision of a deflector (18) having a deflector surface (19) flows (15) can be presented such that a greater proportion of the flow including droplets or other matter which may result in surface deposition or errosion will pass directly through an aperture (7, 17) rather than impinge upon the flank surfaces of the restrictor (14). Furthermore, the deflector (18) is dimensioned such that surfaces which may be susceptible to deposition have dimensions smaller than the aperture (17).

Abstract: A vibration damper (28) is disclosed for use in a turbomachine, the turbomachine comprising at least one turbine rotor (19) having a plurality of radially extending blades (16, 17). Each blade has an aerofoil (22), a platform (21) and a stem (20). The vibration damper (28) has a seal-region (29) which comprises a pair of sealing surfaces (24, 25) configured for engagement with respective contact surfaces (24, 25) provided on adjacent blade platforms (21). The vibration damper (28) also has a mass-region (30) which is configured to extend radially inwardly from the seal-region (29) and to terminate at a position located between adjacent blade stems (20) (FIG. 4).

Abstract: A gas turbine engine arrangement (1) comprises a first gas turbine engine (10), a second gas turbine engine (70), a differential gearbox (57) and an electrical generator (112). The differential gearbox (57) has a first input drive (54), a second input drive (78) and an output drive (110). The output drive (110) of the differential gearbox (57) is arranged to drive the electrical generator (112) via an external, accessory, gearbox (56). The external, accessory, gearbox (56) drives other accessories (116, 120). The first gas turbine (10) is arranged to drive the first input drive (54) of the differential gearbox (57) and the second gas turbine engine (70) is arranged to drive the second input drive (78) of the differential gearbox (57). The electrical generator (112) and accessories (116, 120) are driven at a constant frequency speed/frequency.

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 fan casing for a gas turbine engine has a fan track radially outward of the fan blades, and the fan track has sufficient strength and stiffness that, if a blade is released, it is broken up and deflected by the fan track rather than passing through to a containment system as in known arrangements. Optionally, a weakened region in the fan track may be provided, so that the leading edge portion of the blade will penetrate the fan track and be contained within the fan casing. This is particularly suitable for fan blades in which the stiffness and compressive strength are significantly higher in the leading edge region than in the remainder of the blade; for example, hollow metal fan blades or composite fan blades having a metal leading edge cap.

Abstract: It is difficult to bend materials for forming beyond 180° in terms of bend angle due to the entrant nature of prior press forming arrangements including a press tool with a press recess of a static nature. By providing a press recess which is formed from actuators allowed to dynamically shift about a deflection member it is possible as a press tool engages and forces a material to be formed into the press recess to envelope the press tool and therefore achieve greater than 180° bending angles. The actuators are formed in a stack with alternate left right presentation of shaped receiving apertures which include an actuator surface 34 engaged by the material to be formed in order to cause the necessary deflections during the pressing process.

Abstract: Previous testing of such test pieces as fan blades utilized in gas turbine engines has involved application of paint markings to identify fragments upon fragmentation of the test piece. Such fragmentation causes debris which will obscure paint markings and the paint itself may create clouds of dust obscuring visual images of the test piece under test conditions. By applying an image pattern comprising a number of lingering image patches, typically in the form of thermal patches upon the test components, and arranging the test components to be within an enclosure which is evacuated it will be appreciated that these image patterns linger and can be viewed by an appropriate monitor over a period at least of the test conditions. Utilization of extra visual spectrum radiation images extends the period when clear images of the test piece under test conditions can be seen and analyzed.

Abstract: A static structure is provided such as that used as an engine structure 30 within a gas turbine engine. A structure 30 comprises a hub or core 33 with a concentric ring or casing 32. The hub 33 and casing 32 are secured together through spoke or vane elements 31 which are sloped axially and tangentially relative to a principal axis X-X. In such circumstances any roll torque reaction caused by differentially rotating hub and ring motions is retained by the tangential inclination of the spokes or vanes whilst axial sloping of these spokes or vanes 31 and axially sloping of the struts 34 creates bracing in the direction of the principal axis X-X. In such circumstances essentially robust triangles are formed radially and longitudinally respectively each comprising spokes or vanes 31 and struts 34 secured at axially spaced locations on the hub or core 33.

Abstract: An aerofoil for a gas turbine engine, the aerofoil comprises a leading edge and a trailing edge, pressure and suction surfaces and defines therebetween an internal passage for the flow of cooling fluid therethrough. A particle deflector means is disposed within the passage to deflect particles within a cooling fluid flow away from a region of the aerofoil susceptible to particle buildup and subsequent blockage, such as a cooling passage for a shroud of a blade.

Abstract: By mounting a camera to rotate with a rotating component to be viewed it is possible to review the whole component illuminated by a light source. Generally the component will be specifically marked with target markings to highlight its profile to allow images produced by the camera to be compared for distortion and displacement. Such in situ monitoring arrangements also allow profiling of the surface, and by projection of a grid or matrix onto a component surface any distortion in that matrix is indicative of variations in the surface or through use of astigmatic techniques variations in the incident image pattern can be utilized in order to determine distance variations.

Abstract: A method is disclosed of determining the power demand on a power subsystem (2) of a system (1) by optimising a respective demand-dependent operating characteristic based on one or more operating conditions affecting the power subsystem, the method comprising: using a system-authority (3, 14) to determine system-level power demand limits on the basis of a system-level objective associated with an operating period; inputting the power demand limits to a separate power control processor (4, 16) configured for regulating the power demand on the power subsystem (2); determining each of said operating conditions; and using the power control processor (4, 16) autonomously to determine the overall power demand on the power subsystem (2) within said system-level limits, based on each of said operating conditions, thereby to optimise said operating characteristic. A method of regulating the power demand during the operating period is also disclosed.

Abstract: A compressor variable stator vane arrangement comprises at least one stage of variable stator vanes. A speed sensor measures the rotational speed of the compressor rotor. A pressure sensor measures the outlet pressure of the compressor. A second pressure sensor, a temperature sensor and a third pressure sensor measure the total inlet pressure, the temperature and the ambient pressure at the inlet of the gas turbine engine. A processor determines a target operating line as a function of ambient pressure and total inlet pressure. The target operating line is defined to ensure the gas turbine engine operates simultaneously at both the minimum required compressor speed and the minimum required compressor outlet pressure when commanded to idle to minimise idle thrust and fuel burn. The processor determines if the operating point of the compressor, defined in terms of corrected outlet pressure and corrected rotational speed of the compressor rotor is above or below the target operating line of the compressor.

Abstract: An initial geometry for a nacelle provides an intake at the upstream end of the nacelle and an exhaust at the downstream end of the nacelle. The intake has, in flow series/an intake lip and a diffuser. The intake lip has a highlight defining the boundary between the inner and outer surfaces of the intake lip. On all longitudinal sections containing the axis of the engine (i) the inner and outer surfaces are tangency matched at the highlight, and (ii) the inner and outer surfaces have their maximum curvatures at the highlight.

Abstract: A nacelle for a gas turbine engine has an intake at the upstream end of the nacelle and an exhaust at the downstream end of the nacelle. The intake has, an intake lip and a diffuser. The diffuser has a main diffuser section and an optional shorter straight wall diffuser section. The main diffuser section is bounded by an inner wall of the nacelle, the inner wall curving in the airflow direction of the engine. On each longitudinal section containing the engine axis, at the downstream end of the main diffuser section the inner wall has a non zero curvature. Thus each circumferential position on the inner wall at the downstream end of the main diffuser section has a curvature defined by a respective radius of curvature. However, one or more of the radii of curvature differ from the others of the radii of curvature.

Abstract: A method of making an aerofoil comprises the steps of providing first and second skin panels and first and second web-forming membranes. The web-forming membranes each have a series of elongate slots formed longitudinally therein so as to define a series of alternating wide and narrow strips. The wide strips of one membrane are arranged against the narrow strips of the other membrane and the skin panels are arranged either side of the two web-forming membranes. Parts of the web-forming membranes and parts of the skin panels are treated with a release layer and the sub-assembly is compressed and heated so as to effect diffusion bonding between those parts of the membranes and skin panels which are not treated with the release layer. The sub-assembly is then heated and inflated so as to draw the first and second skin panels apart and that, in turn, causes the web-forming membranes to form webs internally.

Abstract: An initial geometry for a nacelle provides an intake at the upstream end of the nacelle and an exhaust at the downstream end of the nacelle. The intake has in flow series, an intake lip and a diffuser. The intake lip has a highlight defining the boundary between the inner and outer surfaces of the intake lip. On all longitudinal sections containing the axis of the engine (i) the inner and outer surfaces are tangency matched at the highlight, and (ii) the inner and outer surfaces have their maximum curvatures at the highlight.

Abstract: An aerofoil 50 and in particular an aerofoil utilised as a turbine blade within gas turbine engines generally incorporate passages 52, 53 along which fluid flows to provide cooling within the aerofoil 50. Previously straight webs were utilised in order to define passages but such configurations limit design choices with regard to achieving torsional and flap vibrational characteristics. By provision of webs 51 which have chordal variation in a serpentine or S shape wider design choices are provided with respect to achieving torsional and flat vibration control. Webs 51 with such chordal variation are achieved through manufacturing processes which remove forming cores by leaching or a lost wax technique or other erosion process. It will also be understood that chordal variations in the webs can create flow rate variations to facilitate particulate separation in a fluid flow through the passages 52, 53 within an aerofoil.

Abstract: An apparatus for ultrasonically inspecting a component comprises a first ultrasonic transducer for transmitting an ultrasonic signal into a component having rotational symmetry and a second ultrasonic transducer for detecting the reflected, or transmitted, ultrasonic signal. A motor and a turntable produce relative rotation between the rotationally symmetrical component and the first and second transducers. Motors, a carriage and tracks on a frame provide relative radial motion between the rotationally symmetrical component and the first and second transducers to scan the whole of a surface of the rotationally symmetrical component. An ultrasonic signal analyzer analyses the detected ultrasonic signal by monitoring for ultrasonic signals having an amplitude above a predetermined amplitude and not having rotational symmetry and a display provides an indication that any detected ultrasonic signals above the predetermined amplitude and not having rotational symmetry is a potential flaw in the component.

Abstract: An inertia friction welding process comprises: a) providing first and second work pieces to be welded together; b) imparting motion to the first work piece relative to the second work piece thereby imparting kinetic energy to the first work piece relative to the second work piece; c) applying a predetermined force to move one or both of the first and second work pieces towards the other to create an upset length in the work pieces; characterized by; d) measuring the rate of motion of the first work piece relative to the second work piece; e) determining a predicted final upset length from the said measured rate of relative motion and said forth; f) comparing the predicted final upset length with a desired final upset length; g) adjusting the aforesaid kinetic energy to achieve substantially the desired final upset length.

Abstract: A gas turbine engine (10) comprising a rotating member (16), a support structure (22) and a centering device (30), the centering device (30) centres the rotation of the rotating member (16) which is supported within the support structure (22), characterised 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 centre 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 centre condition the first member contacts the biasing surface (46) which is arranged to provide