Abstract: It is the norm to make diffusion bonded and superplastically formed heat exchanger panels from a trio of three sheet stacks, which employs four diffusion bonding stages and three superplastic forming stages. The concept described and claimed obviates one sheet from the central stack and provides only one passageway between the remaining two sheets. The advantages gained include less material and one bonding/superplastic forming stage is obviated with resulting savings in cost, time and machine utilization.

Abstract: In a gas turbine engine, compressor delivery air is fed into air inlets in hollow turbine nozzle guide vanes, and then ejected into the gas stream via holes in the vane walls. Valving is provided so as to provide modulation of the cooling airflow over and above the modulation achieved by compressor output when it changes with engine power setting. Excessive cooling of the gas stream is thus prevented.

Abstract: A turbine (10) for a gas turbine engine includes an annular array of turbine aerofoil blades (12) which are mounted on a disc (19). Each of the aerofoil blades (12) is provided with a radially inner platform (21). Each platform (21) includes a passage (37) into which leaked cooling air flows. The passages (37) are disposed in a direction having a circumferential component so that cooling air is exhausted from them in a direction that is generally opposite to that in which the disc (19) operationally rotates.

Abstract: An apparatus (14) for locating a source of acoustic mission in an article (10) comprises a plurality of spaced transducers (18) which supply output signals corresponding to detected acoustic emission activity to a processor (24). Artificially induced acoustic emissions (12) are generated in the article (10) by directing a laser beam (33) onto the article (10). A camera (40) produces an image of the article (10) and any laser flashes. A processor (42) converts the positions of the laser flashes to coordinates on the article (10). A processor (24) analyses parameters of the acoustic emission in the output signals and the coordinates of the laser flashes to infer the mathematical relationship between the parameters and location of acoustic emissions.

Abstract: A bladed rotor and surround assembly comprising an annular casing, a bladed rotor element that is rotatable about an axis concentrically within the casing, and an annular shroud liner. The shroud liner, typically made up of an annular array of circumferentially abutting shroud liner segments, is disposed within the casing in an annular radial space defined between the casing and an outer circumference of the bladed rotor. The shroud liner segments have location members to locate each segment within the casing. The location members and the annular radial space are configured to enable axial insertion of the shroud liner segment between the bladed rotor and the casing. In addition the location members and the annular radial space allow a limited amount of radial translation of the shroud segment during insertion. The location members also provide a positive radial location to prevent radial translation of the shroud segment once each shroud segment is in a final assembled position.

Abstract: Method and apparatus for measuring distance includes a capacitance probe positioned adjacent a rotating member and within the housing of the rotating member such that the distance between the probe and rotating member can be measured. The rotating member and probe co-operate with each other so as to define a capacitor. An oscillator comprising a transmission line is electrically connected to the probe, the resonat frequency value of which is a function of the capacitance of the capacitor. The change in distance between the rotating member and the probe can therefore be measured.

Abstract: A variable diameter shroud ring (21) for the turbine of a gas turbine engine (10) comprises a support structure (25) which carries an annular array of circumferentially spaced apart ceramic segments (26). The radially outer surfaces of the segments (26) are overlaid by a plurality of circumferentially extending metallic sheets (38). The sheets (38) serve to inhibit gas leakage through gaps between the segments (26) as the diameter of the shroud ring (21) is varied.

Abstract: A jet pipe liner for a gas turbine engine comprises of an inner skin consisting of a multiplicity of longitudinally extending sections arranged edge-to-edge in a circumferential direction and suspended along their edges by a multiplicity of longitudinally extending A-frame members. The supporting members are attached to the inside of the jet pipe and the inner skin sections are clamped along their long edges by double-skinned distal ends of the links of the A-frame members.

Abstract: A vectorable nozzle for a vertical lift aircraft comprising an array of lift flow deflecting vanes mounted in a frame hinged to an undersurface of the aircraft. The nozzle is formed by a plurality of telescopic shroud members which together with the vane frame are mounted at their forwardmost ends. The disposition of the vanes is such that the lift flow is directed downwards when the nozzle is extended. When the nozzle is retracted the flow is vectored rearwards to provide forward thrust. In this position the nozzle generates minimum aerodynamic drag from forward movement of the aircraft. The nozzle preferably is fully stowed within the aircraft, and concealed by surface doors when not in use.

Abstract: A metallic article (10) comprises a bond coating (14,16) on the metallic article (10) and a ceramic thermal barrier coating (18) on the bond coating (14,16). The ceramic thermal barrier (18) coating comprises zirconia stabilized with yttria, calcia, magnesia or india, and erbia to reduce the thermal conductivity of the ceramic thermal barrier coating (18). The ceramic thermal barrier coating (18) is at least 100 microns thick. The erbium atom has an atomic mass greater than the average atomic mass of the zirconium, the yttrium, calcium, magnesium or indium and the oxygen atoms to reduce phonon thermal conductivity of the ceramic thermal barrier coating (18). The ceramic thermal barrier coating (18) comprises 4 to 20 wt % of yttria, 5 to 25 wt % of erbia and the balance is zirconia plus incidental impurities. The erbia absorbs energy in the 0.3 microns to 5 microns waveband to reduce photon thermal conductivity.

Abstract: A ducted fan gas turbine engine is provided with a fan which is carried by a shaft. A frangible fuse ring maintains the shaft carrying the fan coaxial with the engine longitudinal axis. In the event of severe fan damage, the fuse ring (28) fractures and the fan shaft orbits about the engine longitudinal axis. A pair of threaded members (39, 41), one of which is of generally frusto-conical configuration, cooperate as a result of the orbiting motion to restore the coaxial relationship between the fan shaft and the engine longitudinal axis.

Abstract: A linear friction welding oscillator consists of a plurality of individual linear oscillators which are ganged together so as to operate in unison. The total force exerted by the composite oscillator is thus the sum of the output forces of the individual oscillators. The individual oscillators produce variable amplitude, linear reciprocation of an output ram by converting rotary motion into linear motion using conversion/coupling means such as a swash plate connected by a bending elements to drive a crank. Each of the individual oscillator cranks is rotatably engaged with the output ram so as to transmit to it axial, reciprocal movement due to the angular alignment of the swash plate axis with the ram. All of the individual oscillators are mounted in a common frame in which they can be swung in unison so as to vary and control their individual movements in synchronism.

Abstract: A method of coating a component (6) having at least one passage (16) entirely therethrough. The method comprising the steps of applying a coating (28) to a region of the surface (22) of the component (6), adjacent to one end of the passage. Then directing a liquid jet (38) through the other end of the said passage (16) so as to remove at least a portion of any coating material (28) located within, or obstructing, the passage (16). In this method the jet is channelled by a first portion (42) of the passage (16) before it encounters the coating material (28) within, or obstructing, the passage (16). In particular the jet (38) is a water jet, which is used to remove a ceramic coating (28) from a component (6). The method has particular use in clearing cooling holes (16) within combustor components or turbine blades. The method can also be used in the repair of such components (6).

Abstract: A catalytic combustion chamber is provided with at least two catalytic combustion zones arranged in flow series. In a first mode of operation fuel is supplied from first fuel injectors, positioned upstream of the first catalytic combustion zone, into the catalytic combustion chamber and is burnt in the first catalytic combustion zone in order to preheat the subsequent catalytic combustion zones. In the second mode of operation the supply of fuel to the first fuel injectors is reduced and fuel is supplied from second fuel injectors positioned between the first catalytic combustion zone and the second catalytic combustion zone into the space between the first catalytic combustion zone and the second catalytic combustion zone. This prevents the first catalytic zone becoming overheated, and reduces the possibility of the second and third catalytic combustion zones becoming overheated and allows the optimum catalyst to be selected for the first catalytic combustion zone.

Abstract: A titanium aluminide based alloy consisting of 42-48 at % aluminium, 2-5 at % niobium, 3-8 at % zirconium, 0-1 at % boron, 0-0.4 at % silicon and the balance, apart from incidental impurities, is titanium. The titanium aluminize alloy composition has a satisfactory combination of high tensile strength, acceptable ductility at room temperature and low secondary creep rate at elevated temperature, so as to be suitable for use in high temperature applications for example aero-engines and automobile engines. It is suitable for compressor discs and compressor blades of aero-engines.

Abstract: A ceramic thermal barrier coating layer for a superalloy article is caused to adhere to the superalloy article by applying platinum to the superalloy article and heat treating at a temperature of 1100.degree. C. to 1200.degree. C. for one hour. This causes aluminum to diffuse from the superalloy article into the platinum to form a platinum enriched outer layer which generally includes a platinum enriched gamma phase and a platinum enriched gamma prime phase. An alumina layer is formed between the platinum enriched outer layer and a ceramic coating. The platinum enriched gamma phase and the platinum enriched gamma prime phase in the outer layer reduces the migration of transition metal elements to the ceramic coating to enable a very pure alumina layer to be formed.

Abstract: A combustor for a gas turbine engine has a fuel nozzle located in the upstream end thereof and is positioned within a cylinder coaxial with said nozzle. The cylinder comprises at its downstream end an annular flange extending from the cylinder in a generally radial direction. The flange has a plurality of cooling air apertures radially extending therethrough so as to direct cooling air along the face of an adjacent heatshield.

Abstract: A method for determining the resonant frequency of vibration of a rotating blade comprises determining the approximate resonance frequency and rotating a blade at a plurality of frequencies in a range above and below the approximate frequency. At each frequency two measurements are taken representative of synchronous amplitudes at each measurement point (P.sub.1 and P.sub.2) wherein the two points are separated by an angle .beta. and there are an unknown number x of complete synchronous vibrations between the two points. A set of data is provided and a plot of P.sub.1 and P.sub.2 produced, the data being analysed to determine a likely value of x and hence the resonant frequency.

Abstract: An abradable seal comprises a plurality of hollow aluminosilicate spheres in a matrix of aluminium phosphate. The matrix of aluminium phosphate also has an aluminosilicate filler. The hollow aluminosilicate spheres have a diameter in the range of 400 to 1800 microns, preferably a diameter in the range of 800 to 1400 microns. The weight proportion of hollow aluminosilicate spheres in the abradable seal is 30% to 50%. The density of the abradable seal is 1.5 grams per cubic centimeter. The hollow aluminosilicate spheres in the aluminium phosphate matrix have a relatively high temperature capability of approximately 1300.degree. C. maximum. This makes the abradable seal better able to withstand the environment in the turbine of a turbofan gas turbine engine.

Abstract: An annular seal plate for an interstage air riding seal arrangement for the internal cooling system of a gas turbine engine is mounted on a rotatable disc by means of an annular mortise and tenon mounting. The contact faces of the mortise and tenon are angled relative to a radial plane of the disc so that centrifugally generated forces are reacted by the faces in a sense to counter axial tilt so that a seal face of the plate lies exactly in a radial plane, at a design rotational speed, thereby to eliminate convergence or divergence between the seal faces of the air riding seal.