Abstract: Gearboxes for aircraft gas turbine engines, in particular arrangements for journal bearings such gearboxes, and related methods of operating such gearboxes and gas turbine engines. A gearbox for an aircraft gas turbine engine includes: a sun gear; a plurality of planet gears surrounding and engaged with the sun gear; and a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin.

Abstract: A gas turbine engine including: an engine core including a turbine, a compressor, and a core shaft; a fan located upstream of the engine core; a gearbox; and a fan shaft mounting structure including at least two supporting bearings connected to fan shaft. The supporting bearings are located at positions forward of the gearbox. A first bearing separation distance (d1) is defined as an axial distance between the input to the fan and the closest supporting bearing in a rearward direction from the fan. A bearing axial separation (d3) is defined as an axial distance between the closest supporting bearing in the rearward direction from the fan and the closest supporting bearing in a forward direction from the gearbox. A bearing separation ratio defined as: the ? first ? bearing ? separation ? distance ? ( d 1 ) the ? bearing ? axial ? separation ? ( d 3 ) is in a range from 4.1×10?1 to 8.3×10?1.

Abstract: An air-breathing turbojet engine for a hypersonic vehicle is shown. The engine comprises a pump for pumping a cryogenic fuel, an inlet configured to compress inlet air by one or more shocks, a cooler to cool the compressed inlet air using the cryogenic fuel, and a turbo-compressor to compress the air further. A precooler cools the compressed inlet air using compressed cooled air from the turbo-compressor. A combustor receives compressed cooled air from the turbo-compressor and a first portion of the cryogenic fuel for combustion. A first turbine expands and is driven by combustion products, and a second turbine 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 receives combustion products from the first turbine and the second portion of the cryogenic fuel from the second turbine for combustion therein.

Abstract: A fan track liner for a fan containment arrangement for a gas turbine includes a cellular impact structure and a supporting sub-laminate integrally formed with each other from fibre-reinforced material. The fan track liner further includes a ballistic barrier comprising a woven reinforcing fibre ply and a layer of reinforcing fibre felt. There is also disclosed an associated fan containment arrangement and a method of manufacturing a fan track liner.

Abstract: A washing tool for washing the engine core of a gas turbine engine has: a fluid connector, configured to be connected to a supply of engine washing fluid; a nozzle, in fluid communication with the fluid connector and configured to direct the engine washing fluid into the engine core; a fan blade fixture, configured to engage with a fan blade of the gas turbine engine and fix the position of the washing tool relative to the fan blade; and a second fixture, configured to engage with a part of the gas turbine engine that does not rotate about the axis of the gas turbine engine and fix the position of the washing tool relative to said part of the gas turbine engine. A washing system, a waste water collection system, a method of washing an engine core of a gas turbine engine, and a gas turbine engine, are also described.

Abstract: The present disclosure relates to a variable stator vane and a method of fabricating the variable stator vane of a gas turbine engine. The method includes providing at least one fibre sheet. The method further includes rolling the at least one fibre sheet around a mandrel to form a spindle section of the variable stator vane. An excess of material of the at least one fibre sheet remains after forming the spindle section. The method further includes using the excess of material of the at least one fibre sheet to form the at least one aerofoil section of the variable stator vane.

Abstract: A computer implemented method for detecting a damage to a gas turbine engine. The gas turbine engine includes a fan and a plurality of turbine stages including a low pressure turbine stage. The fan is drivably coupled to the low pressure turbine stage. The method includes receiving a first signal indicative of a speed of rotation of the fan. The method further includes receiving a second signal indicative of a speed of rotation of the low pressure turbine stage. The method further includes determining a difference metric representative of a difference between the speed of rotation of the fan and the speed of rotation of the low pressure turbine stage. The method further includes determining whether a damage event has occurred based on whether the difference metric passes a threshold.

Abstract: A gas turbine engine comprising: a combustor configured to initiate combustion; and a turbine comprising a stator vane ring defining a plurality of passageways between adjacent vanes; wherein at least one of the passageways is provided with a restrictor which defines a temporary gas washed surface for the stator vane ring and is configured to be ablated upon initiation of combustion to reveal an operational gas washed surface of the stator vane ring. A method of starting a gas turbine engine is also described.

Abstract: A support assembly for a gas turbine engine is provided. The support assembly includes an outer casing, an inner structure, a strut and a mechanical fastener. The outer casing defines a longitudinal central axis. The inner structure includes a platform and a support portion disposed around the platform. The platform defines an aperture therethrough and the support portion defines a slot therethrough adjacent to the platform. The slot at least partially surrounds the platform and extends axially towards the aperture by an axial slot length along the longitudinal central axis. The strut extends generally radially from the inner structure to the outer casing. The mechanical fastener is received through the aperture of the platform.

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 engine core including a turbine, a compressor, and a core shaft connecting the turbine to the compressor, the turbine being the lowest pressure turbine of the engine and the compressor being the lowest pressure compressor of the engine; a fan located upstream of the engine core; and a gearbox that receives an input from the core shaft and outputs drive to the fan. The engine core further includes three bearings arranged to support the core shaft, the three bearings including a forward bearing and two rearward bearings, and wherein the forwardmost rearward bearing has a bearing stiffness in the range of 30 kN/mm to 100 kN/mm, the bearing stiffness being defined by the radial displacement caused by the application of a radial force at the axial centrepoint of the bearing.

Abstract: Computer-implemented methods for controlling the operation of aircraft, particularly electric or hybrid electric aircraft, are described. One such method, implemented on a Flight Management System (FMS) of an aircraft, comprises: receiving, by the FMS, weather data indicative of weather conditions around the aircraft; and selecting, by the FMS, based on the received weather data, one of a plurality of different pre-defined FMS profiles, each FMS profile corresponding to a different range of weather conditions and defining a different set of aircraft operating parameters. The aircraft may be flown under the control of the FMS using the selected FMS profile.

Abstract: Computer-implemented methods for controlling the operation of aircraft, particularly electric or hybrid electric aircraft, are described. One such method, which may be implemented on a Flight Management System of the aircraft, comprises: receiving weather data indicative of weather conditions between a flight origin and a flight destination of the aircraft; and determining, using a constrained optimization method and a weather data dependent aircraft energy usage model, a three-dimensional flight path for the aircraft from the origin to the destination. The constrained optimization method may determine a flight path constrained by, amongst other things the energy required by an Environmental Control System of the aircraft.

Abstract: Computer-implemented methods for controlling the operation of aircraft, particularly electric or hybrid electric aircraft, are described. One such method, which may be implemented on a Flight Management System (FMS) of the aircraft, comprises: obtaining flight path data for the aircraft, the flight path defining a three-dimensional path from an origin to a destination; receiving weather data indicative of weather conditions along the flight path; and determining an amount of energy required to fly the aircraft along the flight path. The determination uses an aircraft energy usage model whose inputs include the flight path data and the weather data. Based on the determination and a comparison with an amount of stored energy available to the aircraft, the FMS may validate the flight path for flight or reject the flight path.

Abstract: A supersonic jet aircraft and a method of operating the same. The supersonic jet aircraft having at least three turbofan engines and an engine management computer. A first engine of the at least three turbofan engines is configured to be de-activatable during flight to move from an operational state in which it provides thrust to an operational state in which it stops providing thrust. Other engines of the at least three turbofan engines are configured to provide sufficient thrust to the supersonic jet aircraft when the first engine is de-activated such that the aircraft can perform a supersonic climb operation and/or a supersonic cruise operation.

Abstract: A sound absorber for an engine of an aircraft, the sound absorber comprising: a base body having a bottom plate, a wall enclosing the bottom plate and an opening enabling entry of air into the base body; and a porous tongue having a fixed end connected to the wall and a free end; wherein the tongue is porous.

Abstract: A method of manufacturing a composite fan blade with an outer part and a core includes laying up a plurality of continuous plies to achieve a stack, placing the core on a central portion of the stack of continuous plies to achieve an unfolded preform; folding the contin-uous plies about the core, such that the central portion of the stack folds about the core and the first portion is superimposed to the second portion, to achieve a folded preform; apply-ing pressure to the folded preform to achieve a consolidated curved folded preform; curing the consolidated curved folded preform to achieve the composite fan blade.

Abstract: Electrical power system includes: one or more rotary electric machines, each mechanically coupled to a gas turbine engine spool; a set of converter circuits connected to the one or more rotary electric machines for conversion between alternating (ac) and direct current (dc), wherein one or more rotary electric machines and the set of converter circuits are arranged to output a number R?2 of dc power channels, each dc power channel having a respective index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein N>R and each dc load channel has a respective index n=(1, . . . , N). The switching arrangement is operable to connect a number Q?1 of the N load channels to at least two different power channels of the R power channels.

Abstract: Electrical power systems for distributing electrical power in arrangements including one or more gas turbine engines; one such system includes: one or more rotary electric machines, coupled to a gas turbine engine spool; converter circuits connected to the rotary electric machines converting between alternating current (ac) and direct current (dc), wherein the rotary electric machines and the converter circuits output a number R?2 of dc power channels, each channel having an index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein each dc load channel has an index n=(1, . . . , N) and R<N?2R.

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.