Abstract: The disclosure relates to winding arrangements for electrical machine stators. Example embodiments include a coil for a tooth element of an electrical machine stator, the coil formed from a plurality of hairpin wires having pairs of legs passing through first and second slots on opposing radial faces of the tooth element, the coil having n full turns passing around the tooth element, the first and second slots each having 2n+2 slot positions having a depth d? for accommodating a single hairpin wire, the slots each having a first slot position at a first common end and a 2n+2th slot position at a second opposing end, the coil having first and second terminal connections connected to hairpin wires extending through the first and second slots at respective first and second slot positions.

Abstract: A casing assembly for a gas turbine engine includes a plurality of vane casing segments. Each vane casing segment includes an arcuate member and a pair of split-line flanges. Each split-line flange includes a first axial flange end and a second axial flange end. Each split-line flange is fixedly coupled to an adjacent split-line flange of an adjacent vane casing segment. Each vane casing segment includes at least one row of stator vanes welded to the arcuate member. Each split-line flange is at least partially and circumferentially inclined relative to a rotational axis of the gas turbine engine, such that the first axial flange end is circumferentially offset from the second axial-flange end. Further, each split-line flange includes an intersecting portion, such that at least the intersecting portion of each split-line flange is circumferentially inclined relative to the rotational axis.

Abstract: A seal arrangement configured to provide an airtight and fluid-tight seal between a first component and a second component, having a first pressure boundary seal disposable at least partially within the gap between the first component and the second component, the first pressure boundary seal being fixable to one of the first or second components to create an airtight seal with the other of the first or second component, the seal arrangement also having a first flame deflector that is configured to bridge across and cover the gap between the first component and the second component so as to create a fluid-tight seal over the gap between the first component and the second component, where the first flame deflector has a convex external shape so as to prevent any fluid impinging upon the first flame deflector from pooling on the first pressure boundary seal.

Abstract: A centrifugal casting apparatus comprising an upper portion into which molten material is poured, the upper portion having a central rotational axis about which the apparatus is rotated; at least one block runner is connected to the upper portion at the proximal end of the block runner and to at least one mould at the distal end of the block runner, the block runner being mounted substantially perpendicular to the axis of rotation; and wherein the moulds are oriented substantially parallel to the axis of rotation of the centrifugal casting apparatus.

Abstract: A control system for an aircraft hybrid propulsion system comprising a gas turbine engine coupled to an electric generator, a propulsor coupled to an electric motor, and an electrical storage device coupled to the motor and the generator. The control system configured to operate the propulsion system in a first descent mode and a second descent mode. In the first descent mode, the gas turbine engine is operated at a first engine power level and the generator is operated at a first generator power level. In the second descent mode, the gas turbine engine is operated at a second engine power level, higher than the first engine power level, and the generator is operated at a second generator power level, higher than the first generator power level. Electric power generated by the electric generator during operation in the second descent mode is stored in the electrical storage device.

Abstract: The disclosure relates to an electric aircraft propulsion assembly comprising: an electric storage unit; a first electric motor connected to power a first propulsor; a first converter configured as a DC:AC converter having input connections connectable to the electric storage unit and output connections connected across the first electric motor, the first converter configured as a DC:AC converter; a second electric motor connected to power a second propulsor; a second converter connected between the first converter input connections and the second electric motor; and a controller configured to control operation of the first and second converters, wherein the second converter is operable as a DC:AC converter to convert the DC supply from the electric storage unit to an AC supply across the second electric motor and as a DC:DC converter to convert the DC supply from the electric storage unit at a first DC level to a DC supply at the input connections of the first converter at a second DC level.

Abstract: There is provided a fuel management system for a gas turbine engine.

Abstract: The disclosure relates to an electric aircraft propulsion assembly for an electric vertical takeoff and landing, eVTOL, aircraft, the assembly comprising: an electric storage unit; a first electric motor connected to power a first propulsor; a first converter configured as a DC:AC converter for driving the first electric motor and a second electric motor connected to power a second propulsor, a second converter. A controller is connected to control operation of the first and second converters and is configured to operate in a first mode in which the first and second converters are operated as DC:AC converters to drive the first and second electric motors and a second mode in which the first converter is operated to drive the first electric motor to power the first propulsor and the second converter is operated to drive the second electric motor to provide a braking torque on the second propulsor.

Abstract: A system for testing at least one test piece. The system includes a pressure vessel including a first chamber receiving a first fluid at a first pressure. The pressure vessel further includes a second chamber receiving a second fluid. The pressure vessel further includes an actuating membrane fluidly separating the first chamber from the second chamber. The system further includes a test vessel including an internal chamber disposed in fluid communication with the second chamber. The test vessel further includes at least one test wall coupled to the at least one test piece. The system further includes an actuator engaged with the actuating membrane and configured to apply a time-varying force on the actuating membrane while the first pressure is being applied by the first fluid on the actuating membrane.

Abstract: A gas turbine engine comprising a combustor and a fuel management system. The fuel management system comprises a fuel supply line, recirculation line and heat exchanger. The fuel supply line is configured to supply fuel to the combustor. The recirculation line is configured to recirculate excess fuel from the fuel supply line to an engine-located fuel tank via a fuel cooling device. The fuel cooling device is configured to reject heat from the excess fuel in the recirculation line. The heat exchanger is configured to reject heat from a thermal load of the gas turbine engine to fuel in the fuel management system. The heat exchanger is disposed on the fuel supply line or on the recirculation line. The fuel supply line is configured to receive fuel from an external source and from the engine-located fuel tank.

Abstract: A combined cycle engine is formed of a gas turbine cycle coupled with a fuel expansion cycle in which fuel for the gas turbine cycle is the working fluid of the fuel expansion cycle. The fuel expansion cycle comprises, in flow series, a fuel pump for pumping a cryogenic fuel for the gas turbine cycle, a first heat exchanger for heating the fuel, an expander to recover power by expansion of the fuel and to thereby drive a load, and a second heat exchanger to reheat the fuel. The gas turbine cycle comprises, in flow series, a compressor, a combustor for combustion of reheated fuel delivered from the second heat exchanger, and a turbine configured to drive the compressor. The first heat exchanger and the second heat exchanger are stationed downstream of the combustor and configured to transfer heat from combustion products to the fuel in the fuel expansion cycle.

Abstract: A fuel management system for a gas turbine engine, the fuel management system comprising a fuel supply line configured to supply fuel from a system inlet to a combustor of the gas turbine engine via a combustor pump and combustor valve. A heat exchanger is configured to reject heat from a thermal load of the gas turbine engine to fuel in the fuel supply line between the system inlet and the combustor valve. There is a downstream recirculation line configured to recirculate a downstream excess portion of fuel from the fuel supply line, the downstream recirculation line extending from a downstream recirculation point on the fuel supply line between the heat exchanger and the combustor valve.

Abstract: An aircraft propulsion system includes first and second engines and first and second electrical machines coupled to the first and second engines respectively. The first electrical machine is arranged to be driven by electrical power in order to at least partially drive the first engine. The second electrical machine is arranged to be driven by the second engine to generate electrical power. An electrical network allows transmission of electrical power between the electrical machines. A controller is arranged to selectively reduce fuel flow to the first engine and provide electrical power from the second electrical machine to the first electrical machine to drive the first electrical machine, based on expected properties of contrails formed in an exhaust plume of the first engine and/or the second engine. The system allows the formation of contrails by the engines to be managed in order to mitigate climate-warming effects of the contrails.

Abstract: A blower system for a gas turbine engine comprising: a rotor assembly, an airframe port and a routing-control valve. The rotor assembly is configured to be mechanically coupled to a spool of the gas turbine engine. The airframe port is configured to receive and discharge air to an airframe system. The routing-control valve comprises: a primary channel for bidirectional flow between the rotor assembly and the airframe port; a primary valve member configured to open and close the primary channel; and an auxiliary channel branched from the primary channel. The auxiliary channel is configured to bypass the primary valve member for: a first auxiliary flow from the airframe port to the rotor assembly; or a second auxiliary flow for purging air from the rotor assembly to a discharge port. The blower system is configured to operate in an engine drive mode and in a blower mode.

Abstract: A gas turbine engine for an aircraft includes a fan system having a reverse travelling wave first flap mode, Fan RTW, and including a fan located upstream of the engine core; a fan shaft; and a front engine structure arranged to support the fan shaft and having a front engine structure nodding mode comprising a pair of modes at similar, but not equal, natural frequencies in orthogonal directions; and a gearbox. An LP rotor system including the fan system and a gearbox output shaft arranged to drive the fan shaft has a first reverse whirl rotor dynamic mode, Rotor RW, and a first forward whirl rotor dynamic mode, 1FW. The engine has a maximum take-off speed, MTO. A backward whirl frequency margin of: t h e ? ? l o w e s t ? f r e q u e n c y ? o f ? e i t h e r ? m o d e ? F a n ? R T W ? o r ? R o t o r ? R W ? a t ? t h e ? M T O ? s p e e d t h e ? M T O ? s p e e d may be in the range from 15 to 50%.

Abstract: A fuel management system for a gas turbine engine. The fuel management system comprises a fuel supply line configured to supply fuel from an inlet to a combustor of the gas turbine engine. The fuel management system also includes a recirculation line extending from a recirculation point on the fuel supply line and configured to recirculate excess fuel from the fuel supply line for resupply to the fuel supply line. In addition, the fuel management system comprises a heat exchanger configured to reject heat from a thermal load of the gas turbine engine to fuel in the fuel management system. The heat exchanger is disposed on the fuel supply line upstream of the recirculation point or on the recirculation line. The fuel management system further comprises a fuel cooling device disposed along the recirculation line and configured to reject heat from the excess fuel therein.

Abstract: An aircraft hybrid propulsion system comprises an internal combustion engine, an electric motor a propulsor and a combining gearbox. The internal combustion engine is coupled to a first input of the combining gearbox, the electric motor is coupled to a second input of the combining gearbox, and the propulsor is coupled to an output of the combining gearbox, such that the propulsor is driveable in use by either or both of the internal combustion engine and the electric motor. Each of the internal combustion engine and the electric motor is coupled to its respective input by a respective clutch.

Abstract: The present disclosure relates to a geared gas turbine engine for an aircraft. Example embodiments include a gas turbine engine for an aircraft including: an engine core having a turbine, a compressor, and a core shaft connecting the turbine to the compressor; a fan located upstream of the engine core, the fan having a plurality of fan blades; and a gearbox that receives an input from the core shaft to drive the fan at a lower rotational speed than the core shaft, the gearbox having a gear ratio of around 3.4 or higher, wherein the gas turbine engine is configured such that a jet velocity ratio between a first jet velocity exiting from a bypass duct of the engine and a second jet velocity exiting from an exhaust nozzle of the engine core is within a range from around 0.75 to around 0.82.

Abstract: An aircraft propulsion system comprises a propulsor, a motor and a reduction gearbox coupled to a prime mover at an input side, and the propulsor at an output side. The reduction gearbox is configured to provide a reduction ratio between the input and output. The reduction gearbox is configured such that the input side rotates in an opposite direction to the output side, and the prime mover, motor, propulsor and reduction gearbox are configured such that gyroscopic forces of the propulsor, motor, prime mover and reduction gearbox generated during aircraft manoeuvres and/or propulsion system failures are substantially cancelled.

Abstract: A control system of a gas turbine engine is provided. The engine has a fuel flow metering valve which regulates a fuel flow to the engine, and one or more variable geometry components which are movable between different set points to vary an operating configuration of the engine. The control system has an engine fuel control sub-system which provides a fuel flow demand signal for controlling the fuel flow metering valve. The control system further has a variable geometry control sub-system which determines current set points to be adopted by the variable geometry components given the current engine operating condition in order to comply with one or more engine constraints. The control system further has an optimiser that receives the current set points and determines adjusted values of the set points which optimise, while complying with the engine constraints, an objective function modelling a performance characteristic of the engine, the objective function adapting to change in engine performance with time.