Abstract: A stator vane assembly for a gas turbine engine comprises a plurality of aerofoil sectioned vanes supported from a circumferentially extending support member or casing via a circumferentially extending platform or platforms. Each vane is attached at one end to one said platform which is carried from the supporting member, each platform being relatively flexible so that deflections of its respective aerofoil sectioned vane cause it to deform. The mounting between the platform and the supporting member is such as to damp motion of the platform and thus of the aerofoil sectioned vane; in some instances resilient material may be interposed between the platform and supporting member to provide the damping.

Abstract: A method of applying a ceramic coating to a metallic workpiece is proposed in which the workpiece is heated in a range of 500.degree. C. to 950.degree. C. and the coating directly plasma sprayed thereon in an atmosphere of air before the workpiece has formed any considerable oxide skin thereon. In this way the use of the conventional bond coat is avoided, while the amount of tensile stress on the ceramic at working temperature is reduced by the pre-stressing effect thus induced.

Abstract: A powder suitable for flame spraying comprising particles of an alumino silicate glass, each of the particles being hollow and coated with an alloy containing, by weight, 80% nickel, 2.5% aluminium, 15.7% chromium and 1.8% silicon. The resultant coating is particularly suitable for use as a thermal barrier.

Abstract: A rotor blade for a gas turbine engine comprises an aerofoil, shank portion and a root by which the remainder of the blade may be supported from a rotor disc. Cooling for the aerofoil is provided by passages in the leading portion of the aerofoil which are fed with cooling air from an entry aperture and a sealed liquid cooling circuit which contains a cooling liquid. This circuit comprises a liquid feed passage adjacent the trailing edge of the aerofoil and connected adjacent the tip of the aerofoil with a vapor return passage, both passages communicating with a sealed cavity within the shank of the blade. In operation the cooling fluid (e.g. metallic sodium) flows under the influence of centrifugal and other forces along the feed passage, is vaporized and returns to the cavity via the return passage. The cavity acts as a condenser for the fluid.

Abstract: A gas turbine engine is disclosed in which a particularly efficient use of cooling air is made. In this engine, at least part of the cooling of the turbine blades is effected by a bleed of air from one of the compressors. This bleed air is ducted to flow between the shanks of adjacent rotor blades to cool them, and the used bleed air then rejoins the main gas flow of the engine upstream of the turbine rotor.

Abstract: A contact-sensing probe has a movable member including a stylus and is supported on a fixed member at two spaced-apart locations. At each location an a spherical element on the one member is situated between convergent surfaces of the other member. A spring urges the movable member into engagement with the fixed member so that at each location the element slides on the convergent surfaces and by virtue of the convergence thereof attains a positive rest position therebetween. The movable member is displaceable from the rest position against the force of the spring when a force is applied to the stylus and is returnable into the rest position by the spring. The elements and surfaces may be electrical contacts, displacement of the stylus being sensed by any one of the contacts being broken. Alternatively displacement is sensed by a proximity sensor.

Abstract: A metallic coating is applied to a metallic substrate by directing a laser beam on to the substrate and simultaneously directing a gas stream containing entrained particles of the coating material on to the area of laser impingement on the substrate. The particles are melted by the laser beam to form a pool of molten coating metal. Relative movement is effected between the laser beam and substrate so that a pool of molten coating metal traverses the substrate to form a solidified metallic coating which is fused to the metallic substrate.

Abstract: A nozzle guide vane assembly for a gas turbine engine comprises a circumferentially extending array of angularly spaced apart aerofoils each having projections adapted to engage with structure to retain the aerofoil in its longitudinal direction. Inner and outer platform members are separate from the aerofoils and each comprises a thicker support skin and a thinner inner skin. Both skins have aerofoil shaped apertures through which the aerofoils project, the support skin retaining the aerofoil against twisting, circumferential or axial loads and the inner skin serving to define a respective boundary of the gas flow through the assembly. The aerofoil is free to slide through the apertures sufficiently to permit relative expansion in a direction longitudinal of the aerofoil, and sealing means are associated with the inner skins and provide a seal between the skins and the aerofoils.

Abstract: A multi-layer acoustic lining, e.g. for a flow duct in a gas turbine aeroengine, includes Helmholtz-type and tube-type resonators sandwiched between backing and facing sheets. In the invention, the ends of the tube-type resonators abut the Helmholtz resonators but are acoustically divided from them by partition means in such a way that the tube-type resonators differ from each other in resonant frequency. Variation of resonant frequency in the tube-type resonators is achieved by variation of their lengths according to which portion of the partition means acoustically divides them from the Helmholtz-type resonators, the partition means being arranged either step-wise or inclinedly between the backing and facing sheets.

Abstract: A worn titanium blade for a gas turbine engine has metal displaced at its aerofoil tip, so that the aerofoil can be dressed to restore it to length. The titanium is not amenable to cold forging, or to being entirely heated, a forge is therefore provided which has dies which contact only the immediate area containing the metal to be displaced. The dies are heatable so as to heat the said area by conduction and powered so as to apply suitable pressure in a way which brings about isothermal displacement of the titanium.

Abstract: A blade or vane for a gas turbine has a cambered aerofoil made up of a plurality of single crystals of an alloy. Each crystal extends longitudinally of the aerofoil and has a predetermined three-dimensional orientation different from that of the other crystals such that it has an optimum value of a chosen property in directions longitudinal and transverse of the aerofoil.

Abstract: A sheet laminate is utilised in the manufacture of a combustion chamber for a gas turbine engine. The laminate has passages therethrough, which connect with ambient atmosphere via holes. The arrangement creates local relatively thick portions or lands which cause stress concentrations along the passages and lines of holes. Therefore pockets are machined in the rear face of each land, so as to reduce the differences in thickness of the laminate and thereby ensure the more even distribution of stresses.

Abstract: In a coupling (9) between a hub (10) and a shaft (11) internal splines (12) of the hub are interdigitated with external splines (13) of the shaft. The splines are helical. The hub and shaft are further connected by axial pins (14) arranged in bores (15) which are parallel to the common axis (16) of the hub and the shaft and which intersect the interdigitated splines. A screw (21) in the hub engages an end (24) of the shaft. When the screw is tightened the hub is drawn along the hub. The different helix angle of zero result in that the hub becomes locked against axial movement on the shaft and the splines of the hub are urged circumferentially into engagement with the splines of the shaft thereby to take up circumferential clearance between them. The force applied by the screw applies compression to the shaft and tension to the hub so that Poisson's Law opperates to close radial clearance between the hub and the shaft.

Abstract: A gas turbine engine cowling suitable for a helicopter contains a gas turbine engine having a vortex tube separator panel for the purpose of separating water droplets and particulate material from engine inlet air. The vortex tube separator panel is mounted in a duct extending the length of the cowling so that air passing through the duct supplies air for passing through the panel to the engine inlet as well as maintaining a flow of air transverse to the panel. The air flow transverse to the panel ensures that blockage of the panel by ice is substantially reduced or eliminated. Under forward flight conditions, ram air passes through the duct but during hovering, the air flow through the duct is induced by an ejector powered by the exhaust efflux from the engine. The portion of the air flow through the duct which does not enter the gas turbine engine is utilized in the cooling of the engine exhaust efflux in order to reduce the amount of infra-red radiation emitted thereby.

Abstract: A gas turbine engine comprises a compressor, a combustion system and a turbine, the compressor and the turbine being interconnected by a shaft. The combustion system has an initial diffusing section and duct means are provided to convey cooling air from at least part way down the diffusing section, to the turbine. At least one aperture is provided in the duct means and adapted to allow part of the cooling air to flow forwardly of the shaft on its outer surface to cool it.

Abstract: A probe for use in measuring apparatus has a base member including a two-dimensional seat for an intermediate member which, in turn, includes a two-dimensional seat for a stylus holder. The two seats face in opposite directions so that the stylus holder can be displaced from the seated position in either of two opposite directions.

Abstract: An oil tank suitable for an aircraft mounted gas turbine engine is divided into three series connected chambers. Aerated oil after engine use is fed into the first chamber and de-aerated oil withdrawn from the third chamber for engine use. The chambers are interconnected in such a manner that when the tank is inverted, a reservoir of oil is retained within the third chamber to provide a continued supply of oil to the oil outlet for a finite time period and insufficient oil flows into the first chamber from the second to obstruct an air vent provided in the first chamber.

Abstract: An aerofoil blade or vane for a gas turbine engine comprises an aerofoil which includes one only of the two flanks of the trailing edge of the aerofoil and which is an integrally cast structure. The other flank of the trailing edge is formed as a separate piece which is metallurgically bonded to the remainder of the aerofoil through a joint face. The aerofoil is adapted for the supply of cooling fluid to its interior and the joint face is cut away to form an exit passage or passages for cooling fluid which leaves the interior of the aerofoil.

Abstract: A method of removing aluminium containing alloy coatings from nickel or cobalt base alloy substrates in which the coated substrate is immersed in an aqueous mixture of nitric and sulphamic acids until coating dissolution is complete. A solution containing 5 to 30% vol./vol. nitric acid and from 5 to 30% wt./vol. sulphamic acid is preferred.

Abstract: A method of inspecting wax patterns for use in the lost wax casting process comprises coating the pattern with aluminum by vapor diffusion and subsequently inspecting the coated pattern using inspection apparatus adapted for the non-contacting dimensional inspection of electrically conductive workpieces.