Abstract: A bladed rotor for the high pressure compressor of a gas turbine engine comprises a disc carrying an annular array of aerofoil blades in axially extending fir tree root slots. Retention plates carried in radially inner and outer slots prevent axial movement of the blade roots in their slots. A locking member is interposed between an adjacent pair of retention plates to prevent their circumferential movement relative to the disc. The locking member in turn interacts with the disc to anchor itself to the disc.

Abstract: An electrode assembly (10) for an electrochemical machining apparatus comprises a plurality of electrodes (18,20) for location adjacent a workpiece (12) to be machined, at least one of the electrodes (18,20) being movable towards the workpiece (12) during an electrochemical machining operation. The moveable electrodes (18,20) have a machining face (19,21) shaped to a desired contour and at least one side member (32,34) arranged to move with the electrodes (18,20) as the electrodes approach the workpiece (12). The side members (32,34) are fixed to and move with the electrodes (18,20) at all times during the electrochemical machining operation.

Abstract: A multiple layer erosion resistant coating on a substrate comprises alternate layers of tungsten and titanium diboride. All of the layers have the same thickness and preferably have thickness's of between 0.3 and 1 micrometer to give improved erosion resistance. The layers are produced by sputtering.

Abstract: An annular combustor structure particularly suited to staged combustion has a faired centrebody incorporating a diffuser in the head of the combustor. The structure carries fuel injector mountings for pilot and main stage combustion which receive fuel from respective manifolds running around the hollow interior of the structure. There are two annular chambers each containing a fuel manifold, and cooling air passes through the chambers before entering the combustion volume. The manifolds are connected to an external source of fuel by conduits which pass radially through the combustion chamber outer casing walls.

Abstract: A superalloy turbine blade (10) has a MCrA1Y bond coating (22) and a thermal barrier coating (24). The thermal barrier coating (24) comprises a plurality of alternate layers (25, 27) which have different structure to produce a plurality of interfaces (26) substantially parallel to the metallic substrate (20)/bond coating (22) interface. These interfaces (26) provide paths of increased resistance to heat transfer to reduce the thermal conductivity of the thermal barrier coating (24). The structure in the alternate layers (25, 27) of the thermal barrier coating (24) is columnar (28), or segmented, to ensure that the strain tolerance of the thermal barrier coating (24) is not impaired. The columnar grains (28) in the layers (25, 27) extend substantially perpendicular to the metallic substrate (20)/bond coating (22) interface. This enables thermal barrier coatings (24) of reduced thickness and weight to be used.

Abstract: A fuel injection apparatus which is suitable for use with the combustion apparatus of a gas turbine engine, is adapted to produce reduced amounts of noxious emissions. The apparatus comprises a central core which is provided with two fuel supply ducts. The first fuel supply duct supplies fuel for atomization in a swirling airstream; the atomized fuel being subsequently thoroughly mixed with air in an axially elongate mixing duct. The second fuel supply duct supplies fuel to the downstream end of the core where the fuel is atomized by an air flow through a duct surrounding the core before being exhausted from the core downstream end.

Abstract: A coated article includes a superalloy substrate, an intermediate bond coat and a thermal barrier coating. The bond coat may include a platinum aluminide layer underlying a thin oxide layer. The thin oxide layer may include alumina. The coated article has high strength and durability at high temperatures over extended periods of time and thus is especially useful in the form of, e.g., a turbine blade or turbine vane.

Abstract: A combustion chamber which has a primary combustion zone and a secondary combustion zone is provided with a plurality of secondary fuel and air mixing ducts arranged around the primary combustion zone. The secondary fuel and air mixing ducts are defined by a pair of annular walls and by a plurality of walls extending radially between the annular walls. Each secondary fuel and air mixing duct has an aperture to direct a fuel and air mixture into the secondary combustion zone. The apertures have the same flow area. Each secondary fuel and air mixing duct has one or more fuel injectors to inject fuel into the upstream end of the secondary fuel and air mixing duct. This arrangement ensures that the fuel/air ratio emitted from each aperture is within 3.

Abstract: Aerofoil members such as the stator vanes and rotor blades of an axial flow compressor are defined by a number of nominal sections. The leading edge of each nominal section of the blade is set so that an airflow passing therethrough is incident at the optimum angle. The optimum angle is chosen so that the maximum velocities of the airflow at the leading edge are equal. Once the optimum angle has been found for each section of the blade the sections are stacked to define a blade having a leading edge the aerodynamic profile of which ensures that the airflow is incident at the optimum angle along the length of the blade from the root to the tip. The efficiency of the axial flow compressor is improved.

Abstract: A magnetic thrust bearing (110) comprises a magnet (112) mounted on a shaft (114) and a plurality of equi-angularly spaced superconductors (116) mounted on a static structure (118). Each superconductor (116) is mounted onto the static structure (118) by a parallel hinge strip (120) which allows the superconductor (116) to move radially relative to the axis of rotation of the shaft (114). The radial movement of the superconductors (116) changes the cross-sectional area of the magnetic field between the magnet and the superconductors (116) and this changes the stiffness of the magnetic bearing (110). The superconductors (116) move radially due to the pivoting of the parallel hinge strips (120) due to changes in the loads acting on the magnetic bearing (110). It is possible to detect movement of the shaft and to actively move the superconductors to control the stiffness of the magnetic bearing and to control the clearance in the magnetic bearing as in FIG. 5.

Abstract: A power turbine includes pivotable vanes for a variable area nozzle which are accurately and consistently assembled in a first full throat area position by providing an abutment and an abutment surface on gear segment arms attached to spindles at the radially outermost ends of the vanes. When the first vane has been fitted in the 100% throat position by threading its aerofoil portion through a slotted aperture in the turbine casing 10, the remaining vanes are accurately angularly positioned by causing their abutments to abut the abutment surface on the previously fitted vane segment arm.

Abstract: A gas turbine engine combustion chamber which has primary, secondary and tertiary combustion zones in flow series has a secondary fuel and air mixing duct and a tertiary fuel and air mixing duct. The secondary mixing duct has a secondary air intake at its upstream end and the tertiary mixing duct has a tertiary air intake at its upstream end. The tertiary air intake is arranged adjacent to the secondary air intake. A combined secondary and tertiary fuel system is provided to supply fuel to the secondary and tertiary mixing ducts. The fuel system comprises a manifold arranged adjacent to the secondary mixing duct but is spaced from the tertiary mixing duct by the secondary mixing duct. The manifold has apertures to direct fuel towards the tertiary air intake across the secondary air intake. Variations in fuel pressure cause the fuel to flow into the secondary air intake or the tertiary air intake.

Abstract: A ducted fan gas turbine engine is provided with means for measuring the actual temperature of air exhausted from its high pressure compressor and means for computing a theoretical value of that temperature.

Abstract: A gas turbine engine with first and second axial flow compressors and an intercooler therebetween is provided with a diffuser to diffuse the air flow leaving the downstream end of the first axial flow compressor at a first radial distance from the axis to the upstream end of the intercooler at a second radial distance from the axis. The diffuser comprises a first radially extending wall, a second radially extending wall and a plurality of diffuser vanes extending therebetween which define a plurality of generally radially extending diffusing passages. The vanes are wedge shaped. This arrangement provides diffusion in a short axial length.

Abstract: A rotor disc which is suitable for carrying the fan blades of a ducted fan gas turbine engine is constituted by two sub-discs which are maintained in axially spaced apart relationship by a plurality of spacer members. The spacer members are generally axially extending and at least partially define the operational air flow path over the disc.

Abstract: A power turbine includes a stage of pivotable nozzle vanes. The individual vanes are pivoted by connecting them to a toothed unison ring via actuating levers in the form of gear segments. The gear segments only have sufficient teeth to enable pivoting of the vanes between normal maximum and minimum operating angles. If an emergency closure of the nozzle is required, the unison ring pivots the gear therewith, whereupon pins on the unison ring engage projections on each segment, thus causing the segments to continue pivoting the vanes to a closed position.

Abstract: A porous material is manufactured by weaving polycarbonate fibres through a tow of carbon fibres which has been pre-impregnated with an epoxy resin. A second layer of pre-impregnated carbon fibres are superimposed on the woven layer and the epoxy resin is cured to bond the fibres together. A ceramic slurry is applied and allowed To penetrate through the second layer of fibres and part way through the woven layer of fibres to a controlled depth before being dried to form a mask. A thermoplastic powder is then applied to the unmasked region of the woven layer of fibres and sintered. Finally the mask and the polycarbonate fibres are removed chemically to produce a porous material which comprises a sintered thermoplastic layer reinforced with carbon fibres through which channels are provided.

Abstract: In a method of manufacturing a hollow component metallic sheets are diffusion bonded together except where a stop off pattern is applied to the surfaces of the sheets. A gas channel is accommodated in the thickness of the sheets for the entry of pressurised gas under superplastic forming conditions to produce the hollow component. The material defining the gas channel is locally deformed by forging to reduce the height of the gas channel in order that a subsequent fusion welding pass over the deformed area defining the gas channel hermetically seals the gas channel.

Abstract: Gas turbine engine combustor designs are tending to higher operating temperatures and, therefore, utilisation of high temperature materials such as, for example, ceramics, composite material and high temperature nickel alloys. However use of these materials for combustor components leads, in turn, to problems of how to join together those components. A high temperature material combustor barrel and a similar combustor head heatshield are joined to a metal or metal alloy combustor head by means of a lip around the circumference of the head swaged or rolled onto a lip on the barrel trapping the heatshield between them.

Abstract: A method of manufacturing a composite material in which a fibre matt is placed adjacent a plate electrode in ceramic sol. The application of an electric field to the sol via the electrode results in the deposition of sol particles on the electrode which subsequently permeate the fibre matt. The permeated fibre matt is then removed from the sol, dried out and heated to sinter the sol particles.