Abstract: A seal clearance control device for maintaining a radial clearance between turbine blade tips and the surrounding seal ring. The shroud is controlled by a relatively fast response ring and a relatively slow ring the fast ring serving to control the radial growth of the sealing ring and the slow ring serving to control the radial contraction of the seal ring.

Abstract: A centrifugal separator for separating suspensions of oil mist in air and especially intended for use with aircraft engines comprises a rotatable chamber filled with a relatively rigid porous material and driven by a hollow shaft.An inlet for the suspension is provided in one end wall of the chamber and separate outlets for oil and air in the form of an apertured chamber outer wall and apertures in the shaft respectively.

Abstract: A mechanism for varying the angle of attack of stator vanes of a compressor in a turbo machine. The vanes in each row are all connected to a respective encircling ring. The rings from all the rows of variable stators are connected to a beam which lies along the outside of the casing. The beam is connected at about its middle to a screw jack actuator which is bolted to the casing and one end of the beam is pivotted to the casing with a compound pivot which accommodates the compound movement of the beam caused by the straight line movement of the screw jack actuator.

Abstract: A variable area convergent/divergent iris nozzle for a gas turbine engine has a plurality of interdigitated master and slave petals. Each master petal has a pair of axially spaced rollers which run on guide tracks mounted on the engine jet pipe. A pivotable link connects the upstream end of each master petal to a unison ring which is axially movable to translate the petals thereby varying the area of the nozzle.

Abstract: A gas turbine engine cowl has a portion which translates axially of the remainder, to open or close a reverser gas flow gap. A yoke is attached to the fixed cowl upstream of the gap which yoke is engageable with a member on the translating cowl portion, by dropping thereover as the cowl portion closes the gap. Translation of the cowl portion actuates an abutment via a cam mechanism to release the yoke at such a time as to prevent the yoke dropping too soon, which would result in the cowl portion being unlocked.

Abstract: Gas turbine engine power plants sometimes are provided with thrust reversing equipment, the outlet of which is close to the power plant air intake. Such arrangements create re-ingestion problems. There is described herein an apparatus which either maintains the upstream portion of reversed flow in a given position with respect to the plane of the air intake or alternatively destroys the reversed flow entirely.

Abstract: In an electro-chemical machine tool electrolyte drainage flow is acted upon, on its way to the sump, by a device which breaks up the flow into isolated droplets, so as to prevent electrical leakage occurring via the electrolyte flow.

Abstract: A gas turbine powerplant which has two compressor parts alternatively connectable:1. in series for supersonic flight, or,2. in parallel for subsonic flight and particularly useful at take-off. The compressor parts are co-axial and a valve extends obliquely between them having two positions corresponding to the two alternatives above. In the first position the valve allows series flow and in the second position its obliquity deflects the delivery of the first compressor part out into a bypass duct and allows ambient air into the second compressor part.

Abstract: The disclosure of this invention pertains to the method of removing burrs from an electrically conductive article by exposing the article to a plasma flame wherein the parameters of the plasma are so chosen that the plasma becomes concentrated at the burrs and the consequent concentration of heat in the burrs causes the burrs to vaporize or otherwise diminish. The disclosure also pertains to apparatus for supporting the article and moving relative to the flame for a deburring operation.

Abstract: Use of bulk sound absorber-backed spaced-cell honeycomb structures as sound attenuating liners in the flow ducts of gas turbine engines involves the disadvantage that the bulk absorber may soak up water or fuel present in the honeycomb after entry thereinto from the flow duct. In order to drain away liquid before it comes into contact with the bulk absorber, each honeycomb cell communicates with surrounding cells via apertures in the cell walls through which the liquid can drain, and a perforated sheet is provided between the honeycomb layer and the bulk absorber layer. The perforations are such that sound can enter the bulk absorber layer, but the liquid does not, each perforation being a hole having a peripheral flange which protrudes away from the bulk absorber layer into the interior of a respective cell.

Abstract: The disclosure of this invention pertains to a bladed rotor for gas turbine engines wherein each blade has a root portion connected to a blade support element spaced radially outwardly from the rim of a single disc and being of greater axial extent than the rim. The element is connected to the rim by a web extending in part radially outside the rim and in part at the sides of the rim.

Abstract: A solution for removing a diffused aluminium coating from a component made of nickel or cobalt base high temperature alloy, consisting of Nitric Acid 57%, Sulphuric Acid 29% and Water 14%. The solution removes all but traces of nickel or cobalt-rich aluminides and does not attack the substrate material. If said traces have to be removed also, there is used an etching solution consisting of Ferric Chloride Solution 85%, Sulphuric Acid 10% and Hydrofluoric Acid 5%.

Abstract: A gas turbine engine fuel burner comprises the combination of an atomising fuel nozzle and a vaporizing duct in which the atomised fuel is arranged to impinge on the wall of the vaporizing duct and mix with a portion of the compressor delivery air from the engine compressor. The resultant fuel and air mixture flows into the combustion chamber through a plurality of equi-spaced elongated slots formed in the cylindrical wall of the vaporizing duct, each of the elongated slots having its major axis or longest side extending parallel to the longitudinal axis of the duct.

Abstract: A method of operating a plasma welding apparatus producing a plasma arc and having valve means arranged to control gas flow for the plasma arc and power supply means arranged to control welding current for the plasma arc, wherein the plasma arc current, gas flow to the plasma arc and the feed of a filler material to the arc are coordinated for producing a weld. The gas flow and welding current are maintained at a steady rate during the weld run. The gas flow is reduced at a constant rate to a minimum valve of about 30 % of the steady flow rate at the conclusion of the welding run and the welding current is subsequently reduced at a constant rate from the steady value of the welding current.

Abstract: In order to prevent axial movement of blades with respect to their rotor, a locking ring is provided which abuts the blades and is mounted from the disc by a bayonet connection. The blades engage with the ring to prevent its rotation with respect to the disc and consequent disconnection.

Abstract: The high temperature dimensional stability and resistance to thermal shock of silica articles is improved by ensuring that from 45-60% by weight of the article consists of crystalline phase silica. Such levels of crystalline phase silica may be attained by intimately mixing finely divided particles of fused silica and crystalline phase silica, molding the mixture to the required shape and then heating the molded mixture at a temperature sufficiently high enough to sinter the particles, but not high enough to cause rapid crystallization of the fused silica.

Abstract: A duct wall embracing the turbine of a gas turbine engine is cooled by impingement of air jets on to the outside of the wall. For control of the air flow the wall is surrounded by a chamber divided into inlet and outlet regions by a partition having spaced apart portions projecting towards the wall. The air jets emerge from nozzle openings in the free ends of the projections. Air rebounding from the wall enters the spaces between the projections and so does not interfere with the flow of fresh air thereby raising the efficiency of the heat exchange.

Abstract: In a high-power laser system it is proposed that combustion or compressor gases be diverted from the normal flow path through a gas turbine engine into an auxiliary flowpath, and that their composition be subsequently adjusted by burning at least one hydrocarbon fuel in them and possibly also by adding other fuels and substances. Suitable aerodynamic expansion of the resultant gases produces a population inversion in the CO.sub.2 species, which can be utilized in a laser.

Abstract: A high temperature corrosion resistant nickel-base alloy, e.g. for turbine stator blades in gas turbine engines, providing a good balance between mechanical strength, oxidation resistance and compatibility between a coating and a substrate. A preferred composition of the coating alloy, which composition also provides a good balance between sulphidation and oxidation corrosion, is: aluminum 25-30%; chromium 3-14%; tantalum 7-9; yttrium 0.01-0.5%; nickel remainder. An article may be provided in which the coating is combined with a substrate of the same composition except in that the substrate has an aluminum content of 5-6%.

Abstract: A bypass gas turbine engine is mounted from an aircraft pylon by a mounting arrangement in which the engine outer casing and the core gas generator are mounted independently to the pylon and in which all the connections between the outer casing and the pylon and between the core gas generator and the pylon lie in substantially the same two planes.