Abstract: An insert fixture for use in the manufacture of a single crystal component by a hot isostatic pressing process. The insert fixture comprising: at least a lower plate separated from an upper plate by interconnecting members. The upper plate comprises at least a slot for the insertion of the single crystal component. The lower plate features a related engagement feature for engaging with the single crystal component. The insert fixture may be cast from a ceramic material. The insert fixture may be cast from an alumina ceramic or molybdenum alloy. The interconnecting members may be made from a molybdenum alloy.

Abstract: An aircraft comprises a hydrogen-fuelled propulsion system, a plurality of like generally cylindrical hydrogen storage tanks and a conveying system arranged to convey hydrogen from the hydrogen storage tanks to the hydrogen-fuelled propulsion system. The aircraft further comprises a fuselage having a cargo bay (502) including one or more (510A-G) of the plurality of hydrogen storage tanks, the longitudinal axes (511A-G) of the one or more hydrogen storage tanks within the cargo bay extending parallel to the longitudinal axis (501) of the fuselage and lying in one or more planes (595, 597) extending across the width dimension of the cargo bay. The hydrogen storage tanks within the cargo bay have a common aspect ratio R in the range 4.2?R?25.7, allowing the volume of space with the cargo bay occupied by stored hydrogen to be maximised or approximately maximised.

Abstract: A reheat assembly for gas turbine engine including a jetpipe casing having a reheat core section configured to flow air from inlet to outlet; and reheat bypass section configured to bypass air from inlet to outlet, wherein the reheat core section and the reheat bypass section are radially separated by support duct within the jetpipe casing; reheat arrangement including a radially extending flameholder and a core fuel injection port, wherein: the flameholder, mounted to the jetpipe casing, extends through the reheat bypass section and partly into the reheat core section; the flameholder is configured to form a wake-stabilised region within the core flow of air and the bypass flow of air downstream of the flameholder; and the core fuel injection port is: circumferentially aligned with the flameholder upstream of the wake-stabilised region, and configured to discharge fuel into the reheat core section for mixing with the core flow of air.

Abstract: A reheat assembly for a gas turbine engine includes; a jetpipe casing defining a reheat core section configured to duct a core flow of air and a reheat bypass section configured to duct a bypass flow of air. The reheat bypass section is disposed radially outward of the reheat core section, and the reheat core section and the reheat bypass section are at least partially separated by a support duct. An integrated flameholder is mounted to the jetpipe casing, and a fuel pipe is configured to convey fuel to the integrated flameholder. The integrated flameholder includes a flameholder body extending radially inward from the jetpipe casing through the reheat bypass section and into the reheat core section to promote a wake-stabilised region downstream of the body; and an integrated atomiser configured to atomise fuel provided to the integrated flameholder and to discharge the atomised fuel into the wake stabilised region.

Abstract: A reheat assembly for a gas turbine engine includes: a jetpipe casing including: a reheat core section configured to convey a core flow of air from a reheat core inlet to a reheat core outlet; and a reheat bypass section configured to convey a bypass flow of air from a reheat bypass inlet to a reheat bypass outlet radially outward of the reheat core section, wherein the reheat core and reheat bypass sections are radially separated at the reheat core and reheat bypass inlets by a support duct within the jetpipe casing; a reheat arrangement including a radially extending flameholder and a plurality of fuel injection ports including a plurality of core fuel injection ports, wherein: the flameholder is configured to promote a formation of a core flow wake-stabilised region within the core flow of air downstream of the flameholder; and each of the plurality of core fuel injection ports are: circumferentially aligned with the flameholder upstream of the core flow wake-stabilised region, configured to discharge a re

Abstract: A method of friction welding a first component to a second component, the method having the steps of: rotating the first component relative to the second component about a rotation axis; and bringing the first component into contact with the second component; wherein, while the first component and the second component are in contact, a first average force is applied during a first stage of the friction welding process and a second average force is applied during a second stage of the friction welding process; and the second average force is different from the first average force.

Abstract: A tube gallery for a gas turbine engine includes a body. The body includes an external surface. The body also includes a plurality of channels defined in the body. Each channel includes an inlet disposed on the external surface, an outlet spaced apart from the inlet and disposed on the external surface, and a passage extending between and fluidly communicating the inlet to the outlet. The passage of each channel has a non-circular cross-sectional shape. The non-circular cross-sectional shape has a first maximum dimension along a first direction and a second maximum dimension along a second direction orthogonal to the first direction. The first maximum dimension is greater than the second maximum dimension by a factor of at least 1.2.

Abstract: In a gas turbine engine of the type having a high-pressure (HP) spool and a low-pressure (LP) spool, methods of increasing surge margin and compression efficiency at a given thrust are provided. One method increases compression efficiency and comprises transferring mechanical power from the HP spool to the LP spool to reduce a corrected speed of a HP compressor therein and raise a working line of a LP compressor therein. Another method increases surge margin and comprises transferring mechanical power from the LP spool to the HP spool to increase a corrected speed of a HP compressor therein and lower a working line of a LP compressor therein.

Abstract: An organic composite gas storage tank 100 comprises a hollow central portion 106 which is substantially cylindrical and formed integrally with first and second end portions 102, 104, and which defines a longitudinal tank axis 301. The first end portion comprises a hollow truncated conical region which meets the hollow central portion at a first end thereof, the outer and inner radii of the hollow truncated conical region decreasing in a direction along the longitudinal tank axis away from the hollow central portion. An organic fibre winding 107 extends at least between axial positions which coincide with the hollow truncated conical region of the first end portion and the hollow central portion respectively. The first end portion has a higher axial strength than that achievable for hemispherical end portion of a tank of the prior art.

Abstract: There is provided a blower system for providing air to an airframe system, comprising a rotor configured to be mechanically coupled to a spool 440 of a gas turbine engine, wherein the rotor is configured to: in a blower mode, be driven to rotate by the spool to discharge air to an airframe discharge port for supply to an airframe system; and, in an engine drive mode, receive air from an external air source via an impingement port that is configured to direct the received air onto the rotor and thereby drive the rotor to rotate to drive the spool to.

Abstract: A combination of a gas turbine engine and a power electronics for powering aircraft and/or engine systems. The engine includes an engine core comprising a turbine, a combustor, a compressor, and a core shaft connecting the turbine to the compressor, and a fuel circuit for supplying a fuel flow to the combustor. The power electronics is configured to transfer heat produced by the power electronics to a cooling flow formed by a portion of the fuel flow. The fuel circuit is configured to circulate the cooling flow in a loop during selected engine conditions such that the cooling flow transfers heat from the power electronics to a phase change material located on the loop. The phase change material has a phase change temperature at a predetermined limiting temperature whereby the phase change material stores heat from the cooling flow to prevent the power electronics exceeding the limiting temperature.

Abstract: A gas turbine engine has a compression system radius ratio defined as the ratio of the radius of the tip of a fan blade to the radius of the tip of the most downstream compressor blade in the range of from 5 to 9. This results in an optimum balance between installation benefits, operability, maintenance requirements and engine efficiency when the gas turbine engine is installed on an aircraft.

Abstract: A combination of a gas turbine engine and power electronics, includes an engine core and oil circuit to cool and lubricate bearings of the engine core, and a fuel circuit for supplying fuel to the combustor. The fuel circuit includes a low pressure pump for pressurising the fuel to a low pressure, and a high pressure pump to receive the low pressure fuel and increase the pressure to a high pressure for supply to a fuel metering system and the combustor. The engine includes a fuel-oil heat exchanger having a fuel side on the fuel circuit between an outlet of the low pressure pump and an inlet of the high pressure pump, and an oil side on the oil circuit to transfer heat from the oil circuit to the fuel circuit. The power electronics transfers heat to a cooling flow formed by a portion of the low pressure fuel.

Abstract: An aircraft comprising a wing having a spanwise lift distribution extending from a root to a tip, the lift distribution defining an inboard region defining a positive lift contribution, an outboard region defining a negative lift contribution, and an intermediate region defining a neutral lift contribution, the neutral region being spaced from the tip and from the root. A propulsion system is provided, comprising a wing mounted propulsor. The wing mounted propulsor has a rotational axis (x) positioned substantially at a span of the wing where a value of ?Lift/?Span is at a maximum for the span of the wing, and may be located at the intermediate region along the span of the wing.

Abstract: A gas turbine engine comprises a bypass duct and a heat exchanger assembly, the heat exchanger assembly comprising a heat exchanger and a heat exchanger duct having an inlet region, an inflection region and an outlet region. A direction of a centreline of the heat exchanger duct has a tangential component with respect to a principal rotational axis of the gas turbine engine at one or more of the inlet region, the inflection region and the outlet region. The heat exchanger is disposed within the inflection region and configured to transfer heat generated by the gas turbine engine into the flow of air as it passes through the inflection region.

Abstract: A hybrid power system for an aircraft comprises a gas turbine connected to a generator for generating electrical power; an electrical storage device configured to output electrical power; a propulsor; a motor operable to drive the propulsor using electrical power from either or both of the generator and the electrical storage device; and a controller. The controller, to meet propulsor power demand, is configured to control an amount of electrical power generated by the generator, and an amount of electrical power outputted by the electrical storage device. In a first control mode coinciding with an increase in the propulsor power demand sufficient to cause a transient excursion of the operating point of a compressor of the gas turbine from a steady state working line, the controller is further configured to temporarily increase the amount of electrical power outputted by the electrical storage device such that the transient excursion is reduced.

Abstract: The present application discloses a method of determining one or more fuel characteristics of an aviation fuel suitable for powering a gas turbine engine of an aircraft. The method comprises: determining, during use of the gas turbine engine, one or more exhaust content parameters by performing a sensor measurement on an exhaust of the gas turbine engine; and determining one or more fuel characteristics of the fuel based on the one or more exhaust parameters. Also disclosed is a fuel characteristic determination system, a method of operating an aircraft, and an aircraft.

Abstract: The present application discloses a method of determining one or more fuel characteristics of an aviation fuel used for powering a gas turbine engine of an aircraft. The method comprises: determining one or more performance parameters of the gas turbine engine during a first time period of operation of the gas turbine engine; and determining one or more fuel characteristics of the fuel based on the one or more performance parameters. A method of operating an aircraft, a fuel characteristic determination system, and an aircraft are also disclosed.

Abstract: A gas turbine engine comprises a fan mounted to rotate about a main longitudinal axis; an engine core, comprising in axial flow series a compressor, a combustor, and a turbine coupled to the compressor through a shaft; a reduction gearbox that receives an input from the shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the shaft; wherein the compressor comprises a first stage at an inlet and a second stage, downstream of the first stage, comprising respectively a first rotor with a row of first blades and a second rotor with a row of second blades, the first and second blades comprising respective leading edges, trailing edges and tips, and wherein the ratio of a maximum leading edge radius of the first blades to a maximum leading edge radius of the second blades is greater than 2.8.

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.