Abstract: A gas turbine engine combustion chamber includes a first wall and a second wall. The second wall is arranged within and spaced from the first wall to define a cavity between the first wall and the second wall. The first wall has a plurality of impingement apertures extending there-through and the second wall has a plurality of effusion apertures extending there-through. The impingement apertures have a first diameter, a first pitch, and a first area. The effusion apertures have a second diameter, a second pitch, and a second area. The ratio of the first diameter to the second diameter is at least 3, the ratio of the first pitch to the second pitch is at least 4 and the ratio of the first area to the second area is at least 9. This arrangement increases the cooling performance of the effusion apertures in the second wall.

Abstract: A hollow shaft 102 for transmitting torsion or bending forces is disclosed. The hollow shaft 102 comprises a first portion 108 having a first wall thickness t1, a second portion 110 having a second wall thickness t2 which is greater than the first wall thickness t1, and a transition region 112 between the first and second portions 108, 110. The transition region comprises inner 106 and outer annular 104 shoulder fillets, the inner shoulder fillet 106 being axially offset from the outer shoulder fillet 104 towards the first portion 108. In this manner, the local stress concentrations caused by the inner and outer fillets are axially staggered along the transition region.

Abstract: A liner 2 for a composite blade 40 of a gas turbine engine is disclosed. The liner comprises a metallic shoe 4, operable substantially to encase a blade root 42 of a composite blade 40 and defining an inner surface 17 and an outer surface 19. The liner 2 further comprises a retention lug 6 formed on the shoe 4 and comprising inner and outer keys 24, 22 which project from opposed portions of the inner and outer surfaces. The keys are operable to engage corresponding recesses on a dovetail slot and a blade root to resist axial displacement of the composite blade.

Abstract: A windage shield 2 for an array of fasteners 34, the shield 2 comprising a channel 4 for accommodating portions of the fasteners 34 extending into a fluid flow path. The windage shield 2 also comprises a closure flap 12 which extends between opposite side walls 8, 10 of the channel 4 to enclose the interior of the channel 4. The closure flap 12 is displaceable away from at least one of the side walls 8, 10 to provide access to at least one of the fastener portions 34.

Abstract: A gas turbine engine transition duct 34 is used to convey exhaust gas and bypass air away from the engine, towards an exhaust nozzle (not shown). The duct 34 defines the outer extremity of the path for gas and/or air through the duct. The duct comprises a plurality of flat panel members 36 which together define the outer extremity of the path.

Abstract: A blade arrangement (22) comprises an aerofoil (26) and a mounting support (28) to mount the blade arrangement to a disc. The aerofoil (26) is supported on the mounting support (28). The aerofoil (26) comprises a plurality of elongate aerofoil portions (34) arranged adjacent one another to provide the aerofoil.

Abstract: With highly loaded rotors and stators problems can occur with secondary flows sweeping low momentum fluid across the blades reducing efficiency. By provision of collector slots to collect the secondary air and direct that air to a return slot in a rotor hub it is possible to provide impetus to the collected secondary flow to an outlet slot such that there is dispersal of the secondary flow and therefore reduce the effects upon the overall performance of a gas turbine engine incorporating the arrangement.

Abstract: A vane for a gas turbine engine includes a cap arrangement having a cap insert and a cap adapted to receive the insert. The cap insert has a wall defining a through passage from top to bottom of the cap insert for receiving a cable or the like therethrough. The wall has a slot with a convoluted profile.

Abstract: A vane for a duct, such as an exit guide vane for an exhaust duct of a gas turbine engine, includes a vane plate, an interior strut and an internal wall disposed between the vane plate and the strut. The vane further includes a fluid inlet in the form of a scoop arranged to direct bypass fluid from outside the duct into a gap between the vane plate and the internal wall.

Abstract: The present invention relates to a Test apparatus (10) for testing the interaction between through-thickness compression and shear in a test piece (16). The apparatus comprises first and second chocks (12, 14) arranged in use to securely retain a test piece, and first and second races (18, 20) which can be controllably urged towards each other to transmit a known force to the first and second chocks. The first and second chocks and the test piece together form a substantially cylindrical body of a first diameter and. The first and second races define therebetween a substantially cylindrical space of a second diameter for accommodating the chocks, and wherein the second diameter is greater than the first diameter.

Abstract: There is provided a water jet propulsion device 10 for a water vehicle, comprising a main duct 12 having a main inlet 14 that is arranged to be submerged in use and a main outlet 16; a pump disposed between the main inlet 14 and the main outlet 16; and a plurality of injection nozzles 40, 50, 60, 70 each arranged to selectively eject a jet of fluid into a different region A, B, C, D susceptible to cavitation, so as to re-energise the fluid flow in that region.

Abstract: An assembly, for example in a gas turbine engine, includes a rotatable component supported by a bearing in a support structure. A sealing arrangement includes a non-rotating sealing ring which makes sealing contact with sealing features on the rotatable component. The non-rotating sealing ring is radially displaceable with respect to the support structure by means of ribs which engage axially facing support faces of the support structure. The non-rotating sealing ring is radially located by an outer, non-rotating, race of the bearing, by means of a locating surface on a locating body of the non-rotating sealing ring. As a result of this arrangement, the running clearance at the sealing arrangement can be maintained, despite radial displacement of the rotatable component with respect to the support structure, and despite thermal and mechanical deflections of the support structure.

Abstract: A water jet propulsion device 10 for a water vehicle, such as a boat, is disclosed. The propulsion device 10 comprises a main duct 12 having a main inlet 14 that is arranged to be submerged in use and a main outlet 16, an impeller 30 disposed within the main duct 12 between the main inlet 14 and the main outlet 16, and at least one auxiliary duct 24 having an auxiliary inlet 26 that is arranged to be submerged in use and an auxiliary outlet 28 that opens into the main duct 12 upstream of the impeller 30.

Abstract: A machine such as a ship's engine has a superconducting component 15 requiring cooling for its operation, and includes a cooling system 40. The cooling system is operable in first and second modes. In a cool-down phase the cooling system is run in the first mode providing relatively high heat transfer from the superconducting component. On attainment of a desired operating temperature the cooling system is run in the second mode, providing lower heat transfer. This enables a reduced cool-down time of the machine, while allowing economical operation in normal service. The higher level of cooling in the first mode used during the start-up procedure can involve a colder cryogen, or a greater flow of coolant. One way of achieving the latter is to circulate the coolant in normally evacuated regions 16 during the cool-down phase, and then re-establishing the vacuum in these regions for normal service operation.

Abstract: A component of a gas turbine engine is provided. The component includes an external wall which, in use, is exposed on one surface thereof to working gas flowing through the engine. The component further includes effusion cooling holes formed in the external wall. In use, cooling air blows through the cooling holes to form a cooling film on the surface of the external wall exposed to the working gas. The component further includes an air inlet arrangement which receives the cooling air for distribution to the cooling holes. The component further includes a plurality of metering feeds and a plurality of supply plena. The metering feeds meter the cooling air from the air inlet arrangement to respective of the supply plena, which in turn supply the metered cooling air to respective portions of the cooling holes.

Abstract: A containment system 20 is described, e.g. for a gas turbine engine. The system 20 includes a containment casing 22 and may also include a face sheet 30 and a backing layer 32. The casing 22 includes a matrix material 24 and regions 26 formed of a second material different to the matrix material. Fibres 28 are also included, formed of a third material.

Abstract: A securing system is provided for securing a component to a gas turbine engine casing. The system has a core engine casing formed from a front casing portion and a rear casing portion. The casing portions have respective casing flanges at which the casing portions are detachably joined together. The system further has a component flange extending from a component. The component flange is configured so that, when the casing portions are joined together, the component flange is trapped between the casing flanges. One of the casing flanges projects inwards from the casing to form an airtight seal with the component flange on the inside of the casing. The other of the casing flanges projects outwards from the casing to form an airtight seal with the component flange on the outside of the casing.

Abstract: A component such as a casing of a gas turbine engine has an array of holes distributed around a flange. The casing may distort when unsupported, but nevertheless the position accuracy of the holes may be checked by manipulating measured hole positions to lie with known deviations from a best-fit circle. The maximum load and stress required to bring the hole array into conformity with the best-fit circle is calculated and compared with a predetermined maximum. The deviation of the hole positions associated with the best-fit circle from nominal positions can also be calculated.

Abstract: An electrical machine includes a stator including a plurality of electrical phases and a rotor having a plurality of magnets. Each electrical phase includes at least one coil and power electronics. There are means to detect an electrical short circuit in a faulted coil and means to supply an electrical current to the faulted coil when an electrical short circuit is detected in the faulted coil. The means to supply the electrical current to the faulted coil includes one or more un-faulted electrical phases of the electrical machine. The un-faulted electrical phases of the electrical machine are arranged to supply the electrical current to the electrical phase containing the faulted coil. The power electronics of the un-faulted electrical phases are arranged to supply the electrical current from the un-faulted electrical phase to the power electronics of the electrical phase having the faulted coil. This overcomes a problem of a fault in the DC or AC busbar of the electrical machine.

Abstract: A method is provided that enables the identification of a region of a layered composite component that a test signal has passed through. The method comprises applying a label to the test signal as it passes through the region, such that the label applied to the test signal is indicative of the said region. The labelled signal can be identified by a sensor, even if the signal is of low strength and amongst a lot of noise, such as that caused by the multiple reflections and refractions that take place when an acoustic signal passes through a layered composite component.