Abstract: A method of manufacturing a thin wall isogrid or the like casing by a machining process includes the steps of mating a casing with a support, the said support having a substantially continuous support surface engaging at least part of the inner or outer surface of the casing and machining a plurality of recessed pockets in the inner or outer surface of the casing opposite the surface engaged by the said support. The support reacts loads acting on the casing by a machining tool during machining, thereby minimizing distortion of the casing and tearing of the pockets being formed. During the mating process, the casing is deformed such that the support surface engages substantially the whole of the inner or outer surface of the casing.

Abstract: An apparatus (10) for evaluating a liquid hydrocarbon to determine the propensity for coke formation comprising an injector (12), a supply of air (14) arranged to supply air to the injector (12) and a supply of liquid hydrocarbon (16) arranged to supply liquid hydrocarbon to the injector (12). The injector (12) is arranged to atomise the liquid hydrocarbon and to supply the air and atomised liquid hydrocarbon into a chamber (18) and the chamber (18) is arranged to supply atomised liquid hydrocarbon and air to a test pipe (20) and a heater (22) is arranged to heat the test pipe (20). The test pipe (20) is pivotably mounted on a frame (28) such that the orientation of the test pipe (20) relative to the frame (28) is variable. The apparatus (10) is able to simulate conditions within a vent pipe of a lubricant system of an aero gas turbine engine.

Abstract: A composite article includes a composite member, a flexible member and at least one shape memory material member. The composite member has longitudinally extending fibres in a matrix material. The at least one shape memory material member extends substantially parallel to the composite member and the flexible member is positioned between the composite member and the at least one shape memory material member to bond the at least one shape memory material member to the composite member. The composite article is particularly suitable for use as a tab for an exhaust nozzle of a turbofan gas turbine engine.

Abstract: Within hollow structures, such as blade structures in a gas turbine engine, traditionally rigid girdered reinforcement has been utilised to define structure and shape. Such rigid definition can inhibit utilisation of damping fillers within the hollow structure. By providing a web former comprising spaced bond areas suspended upon angled interconnecting membranes a hollow structure is achieved which is flexible and can be used in conjunction with a damping filler to achieve desired performance. The web former supports skins defining the shape and takes some load such that the damping filler does not separate within the hollow structure.

Abstract: A method for measuring the profile of a component in the region of an edge of the component comprises the following steps: determining the position of an edge point of the component; defining a centre line for the component in the region of the edge; and measuring at least one dimension of the component with reference to the centre line.

Abstract: There is a necessity to provide power for some aircraft service functions whilst the main engines (34) are not operational, for example when the aircraft is on the ground, and to start the main engines (34). This demand is met by provision of auxiliary power units (21). Conventionally a single auxiliary power unit (2) is located in the tail of the aircraft and requires fuel lines and relatively high capacity electrical cabling in order to provide electrical power for main engine starting and service functions. The present invention provides an auxiliary power unit (21) mounted on each main engine (34) and coupled together through an electrical distribution system. This provides greater redundancy in the event of failure of an auxiliary power unit (21) as well as reducing overall weight.

Abstract: A fuel valve for a turbine engine, the valve has a fuel inlet connected to a supply of fuel and a purge inlet connected to a supply of purge air. Opening and closing apparatus within the valve selectively supplies air or fuel to a valve outlet. The opening and closing apparatus are movable in sequence from a first position where both the purge air and fuel to the outlet is disabled to a second position where the purge air is enabled and the fuel is disabled to a third position where the purge air is disabled and the fuel is enabled.

Abstract: Transportation of articles such as gas turbine engines can be problematic in view of their size. Traditionally, articles such as gas turbine engines are transported on cradles associated with platforms and bases. It would be desirable to enable manipulation of height and width to allow the assembly of the article, such as a gas turbine engine upon the base to enter apertures such as doors in aircraft fuselages or for minimising width for road or rail or sea transportation. By providing a cradle, having respective cradle sides projecting from a junction in association with a drive mechanism and each side of the cradle coupled to a pivot arm, control of rotation paths can be achieved. Thus, an article such as a gas turbine engine secured to a cradle arrangement can be manipulated between extremes and alternate configurations, defined by rotation paths, through elective association of one or the other of the pivot arms to the cradle and the base.

Abstract: It is necessary to support and manipulate such bulky items as gas turbine engines through appropriate cradle arrangements. It is necessary to allow robust presentation of the gas turbine engine upon a base such that it can be lifted to a position whereby the engine can be rotated to adjust the configuration of the engine within an arrangement. Such manipulation may minimize height or width dependent upon requirements. By provision of lever assemblies comprising lever arms linked together through a pivot link and a cross link rotation by an actuator of one assembly gives consistent presentation of the locator elements defining a centre of rotation for the engine. The arrangement can be locked in a lowered condition for transportation or lifted to allow rotation and re-orientation of the engine with regard to external protuberances to limit width or height.

Abstract: A combustor for a turbine engine has a cooling ring. The cooling ring has an internal corner that is shaped to cause a flow of hot or fuel rich gas flowing over the wall to separate from the wall. The efficiency of the cooling ring is improved.

Abstract: A DC electrical current busbar associated with electrical load circuits and devices as well as sources requires protection. In order to provide such protection Kirchoff's laws are utilized such that electrical current values are substantially simultaneously taken and summed in order to identify deviations from expected differential threshold values. Upon detection of such deviations and generally as a result of a number of successive deviations an electrical isolation device is utilized in order to isolate electrical current to the busbar. The data set of electrical current values can be utilized in order to provide a back up protection system for individual electrical load devices and circuits, by similar comparison with expected values for those devices and circuits.

Abstract: A cooling system for a gas turbine engine (FIG. 1) comprises a pre-swirl arrangement, preferably including a pre-swirl chamber, for providing cooling air to a turbine blade disc, and a ventilation arrangement for providing ventilation air to a rotating component of the gas turbine engine. The cooling system includes an air bypass arrangement, which preferably includes first, second and third air bypass duct portions, for conveying ventilation air away from the pre-swirl arrangement.

Abstract: A pre-reformer (10) comprises a non-electrically conducting gas tight duct (12) and an electrically conducting wire (14) arranged in the duct (12). The electrically conducting wire (14) is electrically isolated from the duct (12). The duct (12) has an inlet (16) for receiving a hydrocarbon fuel at a first end (18) and an outlet (20) for supplying a pre-reformed hydrocarbon fuel at a second end (22). At least the inner surface (24) of the duct (12) is chemically inert with respect to the hydrocarbon fuel. An electrical power supply (26) is electrically connected to the electrically conducting wire (14) and a control means (28) controls the supply of electrical current through the electrically conducting wire (14) to maintain the electrically conducting wire (14) at a temperature to provide selective thermal decomposition of higher hydrocarbons in the hydrocarbon fuel. The performer reduces coking in associated fuel cells and other parts of a fuel cell system.

Abstract: A turbine stage of a gas turbine engine is surrounded by a ring of liner segments. The liner segments can be moved radially in unison towards and away from the tips or fins of blades, by rotation of a connected unison ring, so as to avoid blade fin rub. Alternatively, the segments can be moved in a common direction by bodily movement of the connected unison ring so as to avoid blade fin rub during off axis rotation of the turbine stage.

Abstract: A gas turbine engine arrangement comprises a core engine, a power turbine and a propulsor. The core engine comprises at least one compressor and at least one turbine arranged to drive the at least one compressor and the core engine is arranged in a casing. The power turbine is positioned downstream of the at least one turbine and the power turbine is arranged to drive the propulsor. An electrical machine is arranged upstream of the at least one compressor. The electrical machine comprises a stator and a rotor and the electrical machine comprises a motor/generator. A first clutch selectively connects the rotor of the electrical machine to the power turbine and a second clutch selectively connects the rotor of the electrical machine to the at least one compressor of the core engine.

Abstract: Safe operation of electrical power distribution systems necessitates consideration of the fault level in terms of the potential for electrical current flow upon an earth or other fault within the electrical power distribution system. Previously, electrical power systems have been analysed to provide theoretical fault levels values for different zones of an electrical power distribution system based upon a worse case scenario. However, existing electrical loads will in practice provide a more adaptable and higher fault level. By monitoring and identifying an I-V characteristic upon switching electrical load in practical operation an actual default level at particular nodes in a power distribution system is determinable.

Abstract: In some circumstances such as with regard to contra-rotating turbo prop arrangements in aircraft it is desirable to vary the pitch of the blades and/or provide de-icing facilities. Advantageously, these blade pitch and de-icing facilities could be provided through electrical actuators. Unfortunately, provision of electrical power to such rotating components traditionally requires utilisation of slip rings which are subject to wear. By providing a self-contained electrical generator comprising a first hub and second hub with respective generator parts it is possible to utilise the contra-rotating nature in order to create relative motion and therefore electrical power generation in coils opposed by permanent magnets. Slide contacts for electrical connection are avoided whilst electrical power can be generated within the rotating reference frame defined by the hubs.

Abstract: A device is provided for measuring the clearance between a member and a surface over and relative to which the member moves. The device has a first reference element, and a second reference element which faces the first reference element, and is movable to alter the distance to the first reference element. The device further has a fastening system for fastening the device to the member so that, during the relative motion, the first reference element is held in a fixed position relative to the member and the second reference element slides over the surface. The device further has an urging arrangement which urges the second reference element into contact with the surface so that, as the second reference element slides over the surface and the clearance between the member and the surface varies, the second reference element moves relative to the first reference element. The device further has a sensor which measures the distance between the first and second reference elements.

Abstract: A method of controlling turbine case cooling in a gas turbine engine, the method including monitoring the present state of the engine 32 and using a predictive model based system 44, 46 to predict the future thermal expansion of the turbine case 12 and turbine blades 28, and controlling cooling of the turbine case 12 in response to said prediction to provide a required gap 30 over time.

Abstract: A method of predicting telemetry data for a system under analysis is provided, the method including the steps of: linking a computational fluid dynamics model and a finite element analysis model at a system condition; converging said computational fluid dynamics model and said finite element analysis model to obtain a converged solution; and extracting data from discrete locations in said converged solution to provide predicted telemetry data for said system condition. The predicted telemetry data is typically thermocouple data, thus providing virtual thermocouples for further analysis. A method of validating a system model using the predicted telemetry data is also provided.