Abstract: An improved aluminide coating especially for heat resistant superalloy substrates. Slurry coating compositions of eutectic metal alloy powders and of non-eutectic metal powders. A process for coating the substrates and the coated metal parts. The coatings have improved resistance to developing cracks and to hot corrosion and oxidation.

Abstract: A blade tip clearance control apparatus (10) comprises a plurality of circumferentially arranged spaced wall members (16) located adjacent the rotor path of a plurality of rotor blades (14). Each wall member (16) is mounted on a carrier (18) attached to an annular casing (22) radially outward thereof. Thermal expansion or contraction of the carrier (18) causes radial movement of the wall members (16). The wall members (16) have at least one fluid passage (20) therein. In operation a flow of fluid passing through the fluid passages (20) causes either thermal expansion or contraction of the wall member (16) to different radial positions.

Abstract: A high temperature mounting system useful, for example for ceramic composite flameholders in a gas turbine engine reheat system uses dovetail clamping. A flameholder carries a dovetail projection which is clamped against a further ceramic, intermediate member by wedge blocks on opposite sides of the dovetail. The intermediate member has raised edges with angled faces opposite the dovetail projection against which the wedge blocks bear. The assembly is clamped to a metal support or flange by clamp bolts which pass through each of the wedge blocks and the intermediate member. The included angle of the contact faces is determined by principles of DAZE geometry to keep the bolts from loosening due to differential thermal expansion. Each wedge block is clamped by single bolt and relative expansion between the bolts is absorbed by bolt bending or nut sliding.

Abstract: A seal for use at high temperatures in an interface between a ceramic component and a metal component has a multi-layer construction arranged so that the seal expands disproportionately more in cross-section than in elongation at increasing operating temperatures. The seal comprises a central core made up of a bundle of elongate ceramic fibers surrounded by a layer of braided metal wire and an outer sheath of braided ceramic fiber. The seal may be formed as an O-ring.

Abstract: A fluid flow duct such as the jet pipe of an aircraft gas turbine powerplant has alternatively selectable outlets so that thrust may be directed through either an axial discharge nozzle or through vectorable lift nozzles. Side outlets in the jet pipe leads to lift nozzle on port and starboard sides of the aircraft. Nozzle selection is made by means of a composite diverter valve comprising a sleeve valve to cover the side outlets and a segmented blocker valve to close the jet pipe and deflect engine exhaust through the side outlets. The blocker valve segments are carried on the sleeve valve for simultaneous deployment. The segments are adapted to delay the opening of the side outlets as the sleeve valve translates axially. Specially extended segments co-operate with a shaped duct wall adjacent the outlets to delay their uncovering.

Abstract: A diverter valve arrangement for a fluid flow duct having selectively alternative outlets. In order to avoid an over-area condition during transition an additional valve is provided to delay the effect of operating the main changeover valve. The diverter valve comprises a sleeve valve which covers/uncovers side outlet ports in the duct wall and a blocker valve made up of a plurality of segments pivoted to the inside of the sleeve valve. As the sleeve translates to uncover the side ports the blocker valve leaves deploy to obstruct axial flow. The additional sleeve valve acts as a shuttle and temporarily follows the main sleeve to delay uncovering the side ports.

Abstract: A mounting arrangement for a composite material flameholder in teh reheat system of a gas turbine engine provides for a flameholder to be suspended from a flameholder bracket in the jet pipe by a means of pivotal mounting and to be restrained from movement by a leaf spring mounted trunnion attached between the bracket and the flameholder at a second mounting spaced a short distance away from the first. The resilience of the leaf spring allows movement in directions parallel to a line through the axes of the two mountings in order to accommodate differential thermal growth of the composite flameholders and their metallic supporting structure.

Abstract: A reheat system for a gas turbine engine includes a plurality of radial flameholders constructed of non-metallic material, such as a ceramic composite or carbon/carbon reinforced material, mounted on a metallic support structure in the engine jet pipe. The metallic support structure may be cooled by air from the engine bypass duct, and the non-metallic flameholders are capable of withstanding higher exhaust gas temperatures in the jet exhaust beyond the capability of currently used metal alloy materials. However, the mounting assembly must be capable of absorbing the considerable differential thermal expansion which will take place.

Abstract: A barrier for use in laser drilling. The barrier is placed in front of those surfaces that one wishes to protect from the laser beam. The barrier comprises a thixotropic medium, for example polyacrylamide suspension in water. The medium includes material which will disperse the laser light and material which will emit light when exposed to the laser light. The light emitter materials could be luminescent materials, phosphorescent materials, or fluorescent materials.

Abstract: A connector for conveying hydraulic pressure from a relatively fixed source to a relatively moveable hydraulically actuable arrangement is described. The connector comprises a telescoping assembly of hollow members opposite ends of which have means for joining the connector to hydraulic lines. A first of the telescoping members is formed with an integral annular chamber which is swept by annular piston means carried by a second of the telescoping members interengaged with the first. Dimensions are chosen so that a change in the internal volume of the telescoping members is compensated by the volume displaced by movement of the piston in the chamber whereby the total internal volume of the system remains constant.

Abstract: A vectorable propulsion nozzle has first and second ducts 10, 16 attached to each other by gimbal attachment means 18 to allow universal swivelling of vectoring in any lateral direction. The second duct 16 comprises a supporting ring 28 which has a plurality of guide means 36 in which arcuate ribs 41 are slidably mounted. Each rib 41 is formed integrally with a master flap 38 which together with slave flaps 44 define the geometry and outlet area of the nozzle. To facilitate varying the throat area of the nozzle the flaps 38, 44 are moved bodily along the guide means by actuators. The area of the nozzle can thus be altered independently of the swivelling of the second duct 16. The supporting ring 28 also has formed therein a plurality of openings 30 for thrust reversing which are uncovered when reverser doors 32 are deployed.

Abstract: A method of forming composite materials comprising reinforced fibres, such as carbon fibres 12, embedded in a metal matrix 10, 13. The method comprises forming a first metal sheet 10, laying the reinforcing fibres 12 on the first sheet 10, and explosively forming a second sheet 13 around the fibres to form an explosively joined composite.

Abstract: A method and apparatus for drilling holes through a component (16) from a first surface to a second surface. The method includes the step of applying a thixotropic water soluble medium to the second surface. The medium contains material to disperse the laser light and light emitting material (which could be fluorescent, phosphorescent or luminescent). Monitoring means and beam splitter are provided for monitoring light emitted, or reflected, by the component 16, along the length of the hole drilled by the laser and for monitoring light emitted by the medium. In this way one can detect when the laser breaks through the second surface and also produce an image indicative of the size and shape of the hole.

Abstract: An aircraft has two vectorable front nozzles each mounted in a bearing located within the fuselage near an adjacent wing. Each nozzle is rotatable from a first position in which exhaust air is directed downwards to a second position in which the exhaust air is directed rearwards. In the first position the nozzle resides within a cavity formed in the wing root to reduce nozzle drag when the aircraft is propelled by its rear nozzle only. The front nozzles rotate out of their respective cavities to the second position when they are used for forward thrust. Additionally, the cavity is extended to form a passage through which secondary air entrained by exhaust from the front nozzle operating in the first position adds to the vertical thrust and reduces suck down effects.

Abstract: A nozzle 16 for a turbojet is provided with a thrust deflector mechanism, downstream of the nozzle in the form of one or more target-type thrust reverser plates 18. The plate or plates 18 are movable from a stowed position into the efflux of gases issuing from the nozzle to deflect the exhaust gases and hence redirect the thrust produced by the nozzle obliquely relative to the central axis of the nozzle 16. The plate or plates 18 are mounted in a bearing for rotation about the longitudinal axis of the jet pipe. When rotated the redirected thrust is effectively rotated relative to the central axis of the nozzle. In one embodiment a pair of plates 18 is used and they can also be employed as a conventional thrust reverser.

Abstract: A propulsion nozzle of a gas turbine engine comprising two mutually confronting spaced fixed side walls 14, 16 and two upper and lower mutually confronting spaced movable walls 20, 22 which locate and move in trackways 18 in the side walls. The movable walls 20, 22 each comprise a plurality of pivotally interconnected members which extend transverse to the fixed walls to define a convergent part and throat of the nozzle.A flap 28 is pivotally connected at its upstream end to a downstream end of one of the movable walls 20(b) and is operable, in at least one mode of operation, to cooperate with the fixed walls to define a divergent expansion ramp downstream of the throat of nozzle. In a first mode of operation, the movable walls 20, 22 can be moved along the trackway 18 to cause the members to define a con-di nozzle facing rearwards to produce forward thrust.

Abstract: A variable flow area nozzle suitable for a gas turbine engine equipped with afterburning means comprises first and second ducts, the second duct pivotably mounted to the first and extending downstream from the first duct thereby defining a fluid flow therethrough. The first duct includes a lip which extends downstream through the second duct, the lip being of width corresponding to the internal width of the second duct thereby defining an exit orifice the flow area of which is controlled by the position of the second duct with respect to the lip. The nozzle further comprises a pressurizable chamber located on a side of the lip remote from the fluid flow path, the chamber being defined at least in part by the lip and a portion of the second duct. A vent hole in the lip is provided for admitting fluid into the chamber from fluid flow path.

Abstract: One major problem associated with the design of high-speed vertical take-off or landing aircraft is the requirement to have the front vectorable nozzles of the aircraft deployed in the airstream which passes over the fuselage of the aircraft when they are in use. The nozzles tend to act as air brakes and thus seriously effect the forward speed and flight characteristics of the aircraft. This invention attempts to solve this problem by providing a vectorable nozzle which is rotatable about one axis between a first position in which it is stowed inside a cavity within the aircraft fuselage when not required, and a second position in which it is deployed into the airstream when required.

Abstract: An ejector nozzle comprising an axially translatable member on which is mounted an axisymmetric array of first flaps 36 and hinged seal plates 39 which serve to define a variable area convergent nozzle. The first flaps have cam followers 38 that co-operate with cams 35 to determine the attitude of the first flaps 36. A plurality of second flaps 40 and second seal plates 43 are mounted on the first flaps. The upstream end of the second flaps 40 are spaced from the downstream ends of the first flaps 36 to form an air inlet. An axisymmetric array of third flaps 50 surround the first and second flaps 36,40. The third flaps 50 are pivotally connected at their downstream ends to the downstream ends of the second flaps 40, and are connected at their upstream ends to fixed structure 32,45,47 by pivotal links 49. A fixed ring 46 carrying rollers 51 surrounds the second flaps 40 at a region intermediate their upstream and downstream ends. The rollers 51 provide a fulcrum about which the second flaps 40 rock.

Abstract: A valve for selectively changing the direction of flow of working fluid through a variable cycle engine which comprises a first and second compressor 14,16 spaced along a flow duct 26. The duct 26 having air intakes 42 leading to the second compressor 16 and outlets leading to nozzles 44. The valve comprising a sleeve 30 axially movable along the duct. The sleeve 30 having openings 31 in it in which are located doors 32. Links 36 are connected to each of the doors 32 so that as the sleeve 30 is moved axially the doors 32 are pulled open to open the air inlets 42 and the outlets and simultaneously obturate the flow duct 26. In a second position of the sleeve 30 the doors 32 and the sleeve 30 close off the air inlets and outlets and open the duct to allow the first compressor to supercharge the second compressor.