Abstract: A control system for lift-generating unit, the control system comprising: detector unit for detecting at least one parameter from which stall may be calculated; scaling unit for determining a scale factor dependent on the or each detected parameter; and multiplier unit for multiplying an incoming lift demand signal by the scale factor to provide an outgoing lift demand signal.

Abstract: A computer system programmed to process a large data set includes means for analysing the data set. The means for analysing the data set typically comprises a means for finite element analysis. The computer system also includes means for applying a data compression technique to the analysed data set such that the compressed analysed data set has high fidelity in regions of interest and has lower fidelity in regions of lesser interest. The data compression technique comprises the use of a wavelet compression technique. The computer system comprises a high specification server and a local workstation. This compressed analysed data set is easily managed by the local workstation to produce different cross-sectional displays without reusing the high capability server. The analysed data set for example comprises a 4D data set of a fan blade containment analysis of a casing.

Abstract: A vane fixing apparatus for removably fixing a vane plate (14) to a web (12) is described. The vane fixing apparatus comprises a mounting bracket (16) attached to the vane plate (14), and a mounting block (20,30) held on the web (12) by at least one fastener (18), wherein the mounting block (20,30) is moveable between a first configuration in which the mounting bracket (16) may engage and disengage the mounting block (20,30) and a second configuration in which the mounting block (20,30) securely retains the mounting bracket (16) relative to the web (12), and wherein the mounting block (20,30) is moveable between the first and second configurations by operation of the fastener (18).

Abstract: A fastener arrangement 22 for fastening two or more articles 62 together, the two or more articles 62 having a first length, the fastener arrangement 22 comprising: a fastener 24 including an elongate clamping member 36 for being received in an aperture 64 of the two or more articles 62, the elongate clamping member 36 being movable between a contracted configuration in which the elongate clamping member 36 has a length which is less than the first length and a lengthened configuration in which the elongate clamping member 36 has a length which is greater than the first length, the elongate clamping member 36 being resiliently biased towards the contracted configuration; and an actuator 50 for moving the elongate clamping member 36, while in the aperture 64 of the two or more articles 62, from the contracted configuration towards the lengthened configuration to enable the elongate clamping member 36 to protrude through the aperture 64 and to engage the articles 62 in a clamping manner.

Abstract: A vane for a duct, such as an exit guide vane for an exhaust duct of a gas turbine engine, comprises a vane plate, an interior strut and an internal wall disposed between the vane plate and the strut. The vane further comprises a fluid inlet in the form of a scoop arranged to direct bypass fluid from outside the duct into a gap between the vane plate and the internal wall.

Abstract: An acoustic panel for a fan casing of a gas turbine engine includes one or more Helmholtz resonators to absorb acoustic energy propagated upstream from the fan. By arranging that the periodic air flow out of the resonators has some axial momentum, by inclining the passages that exit from the necks of the resonators in a downstream direction, some of the energy in this air flow can be realised as a useful pressure rise in the direction of the air flow into the fan, rather than a pressure drop as in known acoustic panels.

Abstract: A rotor blade tip clearance control apparatus for a gas turbine engine includes a plurality of circumferentially distributed segments which form an annular shroud surrounding the outer tips of a row of rotor blades. A mechanical arrangement is operatively connected to the segments. Actuation of the arrangement causes the segments to move in a radial direction thereby controlling a clearance between the segments and the outer tips. A case cooling system supplies cooling air to an engine case to which the segments are mounted. The cooling air regulates thermal expansion of the case and thereby also controls the clearance between the segments and the outer tips.

Abstract: A rotor assembly for a gas turbine engine, the rotor assembly comprises at least two rotors defining a cavity therebetween. A first rotor defines a cooling air inlet in its radially inward portion. A second rotor defines a cooling air outlet in its radially outward portion, such that the cooling air passes radially outwardly through the cavity.

Abstract: An assembly comprises first and second components provided with holes receiving a retaining element in the form of a pin, in order to retain the components together. The pin is made from a shape memory effect material, and is inserted into the holes in a straight configuration, following which a change in temperature causes a retaining portion of the pin to deform into a second configuration, in which withdrawal of the pin is prevented.

Abstract: A health monitoring arrangement for a solenoid includes an armature for coupling to the solenoid, the armature being displaceable proportional to a driving current applied to the solenoid. A monitoring coil is wound around the armature such that the armature is displaceable relative to the monitoring coil. A voltage monitor coupled to the monitoring coil generates a voltage signature in respect of the solenoid that is proportional to the armature displacement. An analyzer analyzes the voltage signature to determine the health of the solenoid. Also a method of monitoring the health of a solenoid is provided.

Abstract: A vibration damper assembly is provided between two shrouds of adjacent turbine blades. A pair of confronting passages are provided, one in each of the shrouds and a vibration damper is located in both of the confronting passages. The vibration damper comprises a structure which when heated expands outwardly so as to engage with the walls of the passages. The vibration damper may be a sheet metal shape memory nickel base alloy wound into an open spiral and provided in circular cross-section passages.

Abstract: A sacrificial liner is provided for an injector access aperture in a combustor casing. The liner has an outer annular surface and an eccentric inner annular surface. The liner serves to protect the combustor outer casing from wear by a series of piston rings mounted in a seal carrier. The eccentricity of the surfaces prevent excess contact pressure between the piston rings and the seal carrier to improve the life of these components.

Abstract: A bypass turbofan engine comprises a first propulsion system and a second propulsion system. The first propulsion system comprises a first fan rotor, a core engine, a first low pressure turbine and a first fan shaft drivingly connecting the first turbine and the first fan rotor. The second propulsion system comprises a second fan shaft drivingly connecting to a second fan rotor and the first propulsion system and arranged so that the first and second shafts are not coaxial with one another.

Abstract: Transportation of larger diameter gas turbine engines can be problematic. In such circumstances it is known to separate the fan assembly (30) from the engine core (1) and other parts to facilitate transportation. Separation of the fan assembly (30) and engine core (1) can require a gantry which adds to inconvenience and costs. By utilizing a platform (2, 44) with suspender members (43) in the form of boot straps (43) which extend down from an existing pylon (31) it is possible to remove an engine core (1) through a carriage dolly (3, 45) which moves along a rail (21 within the platform (2, 44) generally laterally until it is possible to lower the engine upon the platform to ground level. The platform (2, 44) and carriage dolly (3, 45) can then act as a stand for transportation of the engine core.

Abstract: The present invention provides an actuating apparatus for moving relatively rotatable components. In one embodiment the apparatus comprises: a bearing (30) including first (34) and second (36) relatively rotatable bearing elements for mounting respective first (18) and second (12) rotatable components for relative rotation about a common axis; a pneumatic or hydraulic actuator having a pair of co-acting parts (44, 54), including a first part (54) fixed with respect to the said first rotatable element and a second part (44) fixed with respect to the said second rotatable element; and, means (110) for energising and/or de-energising said actuator means to effect movement of the said co-acting parts and thereby relative rotation of the said first and second bearing elements about the said bearing axis.

Abstract: In the casting of a single crystal component, such as a turbine blade, by the lost wax casting technique, one or more ceramic pieces are positioned on a wax pattern at locations corresponding to parts of the cast component where relatively quick solidification of molten metal may occur during casting. A coating is subsequently formed around the wax pattern to define a mould, whereupon the wax is removed to leave the one or more ceramic pieces within the formed mould.

Abstract: An axial compressor comprises a stator component and a rotor component, which cooperate to perform work on a fluid flow in a primary flow-passage defined by the stator and rotor components, the stator component and the rotor component further defining a secondary flow-passage which interconnects a higher pressure region and a lower pressure region of the primary flow-passage, the rotor component being provided with at least one secondary rotor element which, in normal operation of the machine, pumps a bypass flow of fluid through the secondary flow passage from the lower pressure region to the higher pressure region.

Abstract: A fan blade containment assembly (38) for a turbofan gas turbine engine (10) comprises a cylindrical, or frustoconical, casing (40) arranged to surround an arrangement of fan blades (26). At least one hollow tubular member (66) is arranged radially within and secured to the casing (40) and the at least one hollow tubular member (66) contains a filler material (68). The at least one hollow tubular member (66) extends circumferentially. The hollow tubular member (66) is helical and the axial spacing between the adjacent turns of the tubular member (66) varies and the density of the filler material (68) varies in order to match the severity of the impact expected at each axial location along the casing 40 of the fan blade containment assembly (38).

Abstract: A compressor or fan casing is provided with a casing treatment to improve the surge margin of an unshrouded rotor stage. The casing treatment takes the form of an insert (20) let into the casing wall (10) to provide a plurality of re-circulation grooves (22) in the wall circumscribing the path of the rotor blade tips. The insert consists of a plurality of arcuate insert segments (20) made of a carbon fiber reinforced resin. In the preferred construction each arcuate segment (20) is formed with axially extending tangs (28,29) on either side that are received into the correspondingly shaped sides (38,40) of a receiving channel (16) in the casing wall (10). The casing (10) may be split on a diametric plane, thus exposing groove ends (38,40), into which the tangs (28,29) carried by the inserts (20) can be slid before the casing (10) is finally assembled.

Abstract: A shroudless turbine rotor blade of the type having a platform damper interface, is provided with at least one slot which extends from the aerofoil side of a platform flow boundary to a point in the root. The slot extends between opposing flanks of the blade so as to divide the platform and partially divide the root. The segregated root is made more flexible by the slot which provides for greater platform vibratory amplitudes for a given length of root. The increased platform motion provides for improved dampability when the blade vibrates. The slot also provides a pair of confronting platform surfaces which are urged into mutual contact by centrifugal load acting on the blade to create an additional damping interface.