Abstract: In a fluid system for a gas turbine engine, oil is supplied from an oil tank (10) by a constant displacement pump (12) to lubricate engine components (18). The oil is supplied to the components (18) via a heat exchanger (16) in which oil and fuel are placed in direct heat exchange relationship. The flow of oil to the components (18) is controlled by recirculating a proportion of the oil flow through a bypass (20). The bypass (20) regulates the flow of oil to the components (18) so that the amount of heat transferred to the fuel in the heat exchanger (16) is controlled. At low engine powers a greater proportion of the oil flows through the bypass (20) to reduce the oil flow to the components (18). This reduces the heat transferred to the fuel in the heat exchanger (16) and so prevents overheating of the fuel.

Abstract: A retaining arrangement for joining together two components such as a rim coverplate 10 and a rotor disc 12 in a gas turbine engine. The arrangement comprising a channel 54 formed by respective formations 26, 52 on the disc 12 and coverplate 10, which channel 54 locates one or more annular ring member 66 which prevents relative axial movement therebetween. Engageable abutment formations 18, 46 are provided respectively on the disc 12 and coverplate 10, to prevent relative pivotal movement.

Abstract: A stator core 2 comprises laminations (9) of low loss stator iron forming a body of magnetic nature and lamination components (11) of high thermal conductivity material regularly arranged within that body. The high thermal conductivity components (11) increasing the effective radial thermal conductivity rate of the core 2 whereby temperature gradients are reduced in comparison with previous stator cores. Thus, there is a reduction in operational temperature of the electrical insulation on the stator windings.

Abstract: A bearing arrangement incorporates a cage in order to locate bearings between races. The bearing cage is associated with channels such that oil flow is specifically directed by those channels for oil lubricant control. The channels typically have a central channel which diverges at either end in to channels such that grooves, slots or fluting specifically guides and directs oil flow in order to lubricate opposing surfaces of the arrangement, remove excess lubricant oil and provide a more even oil distribution. In such circumstances higher bearing arrangement performance can be achieved without provision of directed oil feed passages within the arrangement.

Abstract: The present application relates to fuel flow limit calculator (12) for use with a fuel control system (30) of an engine (10) comprising a fuel delivery means (28) and a compressor (16). The fuel control system (12) seeks to control the fuel/air ratio (FAR) near the weak extinction limit of the engine (10) as calculated by the fuel flow limit calculator (12). Both the static (PS3) and total (P3) pressure are measured at the exit of compressor (16). This enables a flow reference value (Q3) to be determined so that the air mass flow (W3) can be calculated and the limiting fuel/air ratio calculated. An advantage of the present invention is that it does not require stable combustion for satisfactory operation and allows the occurrence of preferential extinction within an annular combustor (22) to be beneficially utilised.

Abstract: A gas turbine engine comprising a ventilation zone defined between a core engine casing and a core fairing and having a discharge nozzle, the engine further comprises a pre-cooler having a flow of coolant therethrough and which coolant being ducted into the ventilation zone wherein an additional ventilation zone outlet system is provided and comprises a variable area outlet.

Abstract: An aerofoil (35) for example a fan blade (26) comprises a leading edge (36), a trailing edge (38), a concave pressure surface extending (40) from the leading edge (36) to the trailing edge (38) and a convex suction surface (42) extending from the leading edge (36) to the trailing edge (38). The aerofoil (35) comprises a metal foam (50) arranged within a cavity defined by metal workpieces (52, 54). The metal foam (50) of the aerofoil (26) ideally has a density of less than 1g/cm3, is cheaper to manufacture and has improved fatigue behaviour and impact capability.

Abstract: A sensor 30 has first and second electrodes 32A, 32B spaced to define a gap 34 therebetween. The electrodes are formed on a substrate which can be covered with a film of material. The width of the gap 34 is different at different positions on the electrodes 32. This results in a sensing characteristic which can be made substantially linear, without sensitivity varying with film thickness, which arises from the use of a constant gap width. The sensor can be used to detect or measure film or liquid layer thickness, or solid material deposition.

Abstract: A fluid flow control device (26, 28) comprising a guide member (30) to guide a fluid passing through a duct (22, 24, 76), the guide member (30) being movable between first and second positions; and an urging arrangement (32) capable of providing an urging force (F1) to urge the guide member (30) towards the first position, characterised in that the urging arrangement (32) is a resilient torsion bar that is formed so as to allow the guide member (30) to be moved towards the second position by a pressure force (F2) exceeding and opposite to the urging force (F1), the pressure force (F2) being provided by a pressure difference across the guide member (30).

Abstract: A gas turbine engine comprising a bypass duct defined radially outwardly by a nacelle and radially inwardly by a core engine casing. The nacelle comprises a thrust reverser unit having at least one blocker door rotatably attached to a static part and slidably connected to a translating part. The translating part is arranged to move between a stowed position and a deployed position and in the deployed position the blocker door spans the bypass duct. In the stowed position the blocker door is stowed inside the translating part and does not form part of an airwash surface of the bypass duct.

Abstract: The present invention provides a retaining washer for retaining threaded fasteners, such as bolts, that have been inadvertently loosened, in use. The invention finds particular application in gas turbine engines and in aircraft in general where wire locking of threaded fasteners has traditionally been employed. The washer (10) comprises a base member (14) having a plurality of apertures (18) each for receiving the shank of a respective bolt (20) or stud part of a threaded fastener, and engagement means (16) extending from the base member for engagement with respective bolt head or nut parts of the fasteners to retain the said head or nut parts with respect to the washer in the event of inadvertent loosening. The said engagement means is deformable between an open configuration which enables access to the bolt head or nut parts of the fasteners for tightening and/or removal thereof and a closed configuration in which the bolt head or nut part are captively retained with the washer.

Abstract: A control system for a gas turbine engine provides a combined power and data bus that connects a Electrical Engine Controller with electrically actuated pumps, actuators and valves. A scheduler within the Electrical Engine Controller divides the information to be sent out into minor time frames. Each electrically actuated component reads and acts on data from a predetermined minor time frame.

Abstract: A control arrangement (10) comprises a first selectable controller (12) for controlling an action, and a second selectable controller (14) for controlling the action. The arrangement also includes a selector (22) for selecting one of the controllers (12, 14) to control the action. The arrangement (10) further includes a first heat exchanger (16) associated with the first controller (12) to effect a transfer of heat between the first controller (12) and the first heat exchanger (16). The arrangement also includes a second heat exchanger (18) associated with the second controller (14) to effect a transfer of heat between the second controller (14) and the second heat exchanger (18).

Abstract: A method for providing an indication of thrust available from a gas turbine engine, the method comprises measuring fan aerodynamic speed to produce an actual fan aerodynamic speed measurement, determining a difference between the actual fan aerodynamic speed measurement and an expected fan aerodynamic speed measurement, and if the difference is less than a predetermined threshold value, indicating that sufficient thrust is available.

Abstract: A panel assembly of the kind found in the air intake of a gas turbine engine or a fan duct is designed to be demountable for maintenance purposes. Consequently there exists between the panels a gap to be sealed. The invention provides a deformable seal for the purpose comprising an elongate, hollow resilient member mounted on a flange at the edge of one of the panels and arranged to be pressed against a flange at the confronting edge of the adjacent panel. The flanges are shaped such that the hollow member when pressed between the flanges effectively seals the gap between the panels and a portion of the seal member lies flush between the panel edges.

Abstract: A component such as a turbine blade of a gas turbine engine includes a film cooling arrangement which is optimized by a process in which a component is manufactured having a film cooling arrangement of an initial design and evaluation of the performance of the film cooling arrangement is conducted, for example on the basis of the blowing rate of cooling holes present in the initial design. The configuration of a cooling hole of the initial design is subsequently modified in order to improve the performance of the film cooling arrangement and a component is manufactured in accordance with the modified design. By way of example, the initial design may provide a single cooling hole 128 and the modification may comprise the provision of additional cooling holes 126, 130, each intersecting the initial cooling hole 128 adjacent its inlet end which opens into a source of cooling fluid 120.

Abstract: A heat transfer arrangement comprises a target member (28 or 30), and an impingement member (32). The impingement member (32) defines a fluid path (38 or 40) there through to direct fluid onto the target member. The arrangement includes a fluid directing formation (42) on the impingement member (32). The fluid path (38 or 40) extends through the fluid directory formation (42) such that the fluid path directs fluid to exit there from at an exit angle that is substantially orthogonal to the fluid directing formation.

Abstract: A compressor or fan casing is provided with a casing treatment to improve the surge margin of an unshrouded rotor stage. The casing treatment takes the form of an insert (20) let into the casing wall (10) to provide a plurality of re-circulation grooves (22) in the wall circumscribing the path of the rotor blade tips. The insert consists of a plurality of arcuate insert segments (20) made of a carbon fibre reinforced resin. In the preferred construction each arcuate segment (20) is formed with axially extending tangs (28,29) on either side that are received into the correspondingly shaped sides (38,40) of a receiving channel (16) in the casing wall (10). The casing (10) may be split on a diametric plane, thus exposing groove ends (38,40), into which the tangs (28,29) carried by the inserts (20) can be slid before the casing (10) is finally assembled.

Abstract: A ballbar is used to assess the accuracy of relative motion between an arbor 2 and a table 4 of a machine tool. Mounting components 8, 10 are secured respectively to the arbor 2 and the table 4. Each mounting component comprises a block 26, 52 which has provision on three orthogonal surfaces for receiving support means 50, 66 for a ballbar 74. By appropriate selection of the mounting faces, it is possible to set up the ballbar 74 to check motion in all three of the operating planes of the machine. The mounting component 8 comprises a ring 12 for fitting over the arbor 2 of the grinding machine, the mounting block 26 being connected to the ring 12 by a rod 24.

Abstract: A fuel injection apparatus (10) for a gas turbine engine (110) comprising a prefilmer (26), the prefilmer (26) comprises a body (50), the body (50) defines an axis (51), an annular surface (40) and a downstream edge (44), the prefilmer (26) arranged so that when working in operative association with the fuel injection apparatus (10) fuel impinges on the surface (40) and flows, by means of a passing airflow, to the downstream edge (44), from where the fuel is shed, characterized in that the fuel injector (10) further comprises a means for circumferentially varying the residence time of the fuel across the surface (40).