Abstract: A combined cycle heat engine (10). The engine (10) comprises a first gas turbine engine (11) comprising a first air compressor (14), a first combustion system (16, 20) and a first turbine system (18, 22), and a second gas turbine engine (32) comprising a second air compressor (36) and a second turbine system (40). The engine further comprises a heat exchanger (38) configured to transfer heat from an exhaust of the first turbine system (18, 22) to compressed air from the second air compressor (36). The first combustion system comprises a first combustor (16) provided downstream of the first air compressor (14) and upstream of the first turbine system (18, 22), and a second combustor (20) downstream of a first turbine section (18) of the first turbine system and upstream of a second turbine section (22) of the first turbine system.

Abstract: A blade wheel of a turbomachine, which blade wheel has a multiplicity of blades which are suitable and provided for extending radially in a flow path of the turbomachine, wherein the blades form a blade entry angle and a blade exit angle. Provision is made whereby the blade wheel forms N blocks of blades, where N?2, wherein the blades of a block have in each case the same blade entry angle and the same blade exit angle, and the blades of at least two mutually adjacent blocks have a different blade entry angle and/or a different blade exit angle. According to a further aspect of the invention, partial gaps that the blades form in relation to an adjacent flow path boundary are varied in mutually adjacent blocks.

Abstract: A gas turbine engine for an aircraft, comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine, the first electric machine having a first maximum output power; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine, the second electric machine having a second maximum output power; and an engine controller configured to identify a condition to the effect that the LP turbine is operating in an unchoked regime, and, in response to an electrical power demand being between zero and the first maximum output power, only extracting electrical power from the first electric machine to meet the electrical power demand.

Abstract: An aircraft gas turbine engine (10) comprises a main engine shaft (22, 23), a main engine shaft bearing arrangement (36, 44, 49, 50) configured to rotatably support the main engine shaft (22, 23) and an electric machine (30) comprising a rotor (34) and a stator (32). The rotor (34) is mounted to the main engine shaft (22, 23) and is rotatably supported by the main engine shaft bearing arrangement (36, 44, 49, 50), and the stator (32) is mounted to static structure (46) of the gas turbine engine (10).

Abstract: An air-breathing turbojet engine (101) for a hypersonic vehicle is shown. The engine comprises a pump for pumping a cryogenic fuel, an inlet (102) configured to compress inlet air by one or more shocks, a cooler (103) to cool the compressed inlet air using the cryogenic fuel, and a turbo-compressor (104) to compress the air further. A combustor (105) receives compressed cooled air from the turbo-compressor and a first portion of the cryogenic fuel for combustion. A first turbine (106) expands and is driven by combustion products, and a second turbine (107) expands and is driven by a second portion of the cryogenic fuel. The first turbine and the second turbine drive the turbo-compressor via a shaft. An afterburner (109) receives combustion products from the first turbine and the second portion of the cryogenic fuel from the second turbine for combustion therein.

Abstract: An apparatus for securing an insert in a hole, the insert having an axis, a section comprising a thread disposed around the axis and a section comprising a plurality of splines, and the hole having a section comprising a corresponding thread and a section comprising a plurality of grooves corresponding to said splines, the apparatus comprising a driver arranged to rotate the insert, a torque measurement device arranged to measure the driving torque applied by the driver, and a controller arranged to cause the driver to drive the insert into the hole until the splines are level in the axial direction with the grooves by rotating the insert in a first direction, and align the splines with the grooves by causing the driver to further rotate the threaded insert whilst measuring the driving torque using the torque measuring device, and stopping the further rotation based on the measured driving torque.

Abstract: The dual rotor electric machine comprises: a stator having one or more slots and one or more stator windings. The dual rotor electric machine further comprises a first rotor arranged to rotate relative to the stator with an airgap therebetween. The first rotor comprises a first rotor excitation element having one or more magnetic pole pairs arranged to interact with the stator windings, the first rotor configured to rotate about an axis (X). The dual rotor electric machine further comprises a second rotor arranged to rotate relative to the stator with an airgap therebetween. The second rotor comprises a second rotor excitation element having one or more magnetic pole pairs arranged to interact with the stator windings, the second rotor being configured to rotate about the axis (X).

Abstract: An electric propulsion unit (102) for an aircraft is shown. A fan (202) produces a pressured airflow (P) by raising the pressure of an incident airflow (I). An electric machine (201) is arranged to drive the fan and is located within a casing (204). A primary cooling circuit (205) is located within the casing, and includes the electric machine and a first pass of a fluid-fluid heat exchanger (208), thereby placing the electric machine and the fluid-fluid heat exchanger in thermal communication. A secondary cooling circuit includes a second pass of the fluid-fluid heat exchanger and an air-fluid heat exchanger (210) located within the pressurised airflow produced by the fan, thereby placing the fluid-fluid heat exchanger and the air-fluid heat exchanger in thermal communication.

Abstract: A propulsion system includes a main gas turbine engine adapted for generating propulsive thrust during subsonic and supersonic flight operations and a supplementary propulsion unit adapted for generating additional thrust. The supplementary propulsion unit has an air intake and an exhaust for gas accelerated by the supplementary propulsion unit to provide the additional thrust and is adapted to generate the additional thrust during a limited range of subsonic flight operations, and to be dormant during other flight operations. The propulsion system has housing for the supplementary propulsion unit, including intake and exhaust covers which are moveable between deployed and stowed configurations. During the limited range of subsonic flight operations the intake and exhaust cover are moved to the deployed configuration to open the intake and the exhaust. During other flight operations the intake and exhaust cover are moved to the stowed configuration to close the intake and the exhaust.

Abstract: There is disclose a fuel cell system including at least one fuel cell and a duct to supply oxidant to the cathode of the at least one fuel cell. The duct includes at least one sorbent getter adapted to extract volatile species from the oxidant. The sorbent getter includes at least one member of the group consisting of magnesium oxide, calcium oxide and manganese oxide. The sorbent getter provides the advantage of extracting volatile species from the oxidant stream.

Abstract: A turbofan engine has an engine core including in flow series a compressor, a combustor and a turbine. The engine further has a fan located upstream of the engine core, has a supersonic intake for slowing down incoming air to subsonic velocities at an inlet to the fan formed by the intake, has a bypass duct surrounding the engine core, wherein the fan generates a core airflow to the engine core and a bypass airflow through the bypass duct, and has a mixer for mixing an exhaust gas flow exiting the engine core and bypass airflow exiting bypass duct. The engine further has a thrust nozzle rearwards of the mixer for discharging mixed flows, the thrust nozzle having a variable area throat. The engine further has a controller controlling the thrust produced by the engine over a range of flight operations including on-the-ground subsonic take-off and subsequent off-the-ground subsonic climb.

Abstract: A torsional mode damping controller in which the controller modifies electrical power to an electrical motor to provide active damping control of torsional vibration in rotating masses. The controller receives a measurement of a rotational speed of the rotating masses ?m and an estimate or a measurement of a torque transmitted between the rotating masses Tsh; based on the received transmitted torque Tsh, generate a compensating torque to suppress vibration Tcom; based on the received rotational speed ?m and the compensating torque Tcom, generate an electromagnetic torque modification signal Tmodi; and modify the electrical power provided to the electrical motor on the basis of the electromagnetic torque modification signal Tmodi. The controller is further configured to generate compensating torque Tcom by applying a filter to the received transmitted torque Tsh, based on plural tunable parameters including a tuning gain K, a cut-off frequency ?n and a resonant damping ratio ?.

Abstract: An engine for an aircraft has 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. The gearbox is arranged to receive an input from a gearbox input shaft portion of the core shaft and to output drive to the fan so as to drive the fan at a lower rotational speed than the core shaft. The gearbox is an epicyclic gearbox and has a sun gear, a plurality of planet gears, a ring gear, and a planet carrier. The planet carrier and the gearbox support each have a torsional stiffness, and a carrier to gearbox support torsional stiffness ratio is greater than or equal to 2.3.

Abstract: A gas turbine engine for an aircraft comprises an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor, wherein a compressor exit temperature is defined as an average temperature of airflow at the exit from the compressor; and a fan located upstream of the engine core, the fan comprising a plurality of fan blades extending from a hub, each fan blade having a leading edge and a trailing edge, wherein a fan rotor entry temperature is defined as an average temperature of airflow across the leading edge of each fan blade at cruise conditions and a fan tip rotor exit temperature is defined as an average temperature of airflow across a radially outer portion of each fan blade at the trailing edge at cruise conditions. A core to fan tip temperature rise ratio is in the range from 2.845 to 3.8.

Abstract: An aircraft comprises a machine body. The machine body encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, a combustor module, and an exhaust module. The machine body comprises either one or two fluid inlet apertures. The or each fluid inlet aperture is configured to allow a fluid flow to enter the machine body and to pass through the heat exchanger module. The heat exchanger module is configured to transfer a waste heat load from the gas turbine engine and the ancillary systems to the fluid flow prior to an entry of the fluid flow into the fan module, and thence into the compressor module, the turbine module, the combustor module, and the exhaust module.

Abstract: A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D). The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module comprises a plurality of radially-extending hollow vanes arranged in a circumferential array with a channel extending axially between each pair of adjacent hollow vanes. The heat exchanger module has a square axial cross-sectional profile, where a side length of the square cross-section is D.

Abstract: A fuel staging system for a gas turbine engine has a plurality of fuel injectors each having a mains burner. The system has a mains manifold connected to a mains delivery line and configured to distribute fuel from the mains delivery line to the mains burner of each of the plurality of fuel injectors, and a check valve disposed in the mains delivery line upstream of the mains manifold. The check valve is configured to permit flow of fuel from the mains delivery line to the mains manifold when the pressure of fuel in the mains delivery line exceeds a threshold pressure.

Abstract: An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. The inner fan is configured to have, in operation, a rate of rotation of from 3 to 8 times that of the outer fan.

Abstract: An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. The inner fan is configured to have, in operation, a tip speed of from 1 to 3 times that of the outer fan.

Abstract: An aerofoil assembly includes a platform and a plurality of aerofoils extending radially outward from the platform. The platform has a first edge, a second edge, and a platform surface disposed between the first edge and the second edge. Each aerofoil has a leading edge proximal to the first edge and a trailing edge distal to the first edge. A pitch spacing is defined between the leading edges of adjacent aerofoils along the platform surface. A mid-pitch location is defined midway along the pitch spacing. The platform defines one or more recesses disposed between the leading edges of the plurality of aerofoils and the first edge. Each of the one or more recesses is disposed proximal to the mid-pitch location between adjacent aerofoils.