Abstract: A gas turbine engine generates noise during use, and one particularly important flight condition for noise generation is take-off. A gas turbine engine that has high efficiency provides low noise, in particular from the fan and the turbine that drives the fan. Values are defined for a noise parameter NP that results in a gas turbine engine having reduced combined fan and turbine noise.

Abstract: A gas turbine engine for an aircraft has an engine core comprising turbine, compressor, and core shaft connecting the turbine to the compressor, the turbine being the lowest pressure turbine of the engine, and having turbine blades, and the compressor being the lowest pressure compressor of the engine; fan located upstream of the engine core; and gearbox that receives an input from the core shaft and outputs drive to the fan. The engine core further has three bearings arranged to support the core shaft, the three bearings having two rearward bearings located downstream of the leading edge of the lowest pressure turbine blade of the turbine at the root of the blade, and/or, when the turbine comprises four sets of turbine blades, downstream of the trailing edge of a turbine blade of the third set of turbine blades from the front of the turbine, at the root of the blade.

Abstract: An aircraft gas turbine engine has an engine core with a turbine, compressor, and core shaft connecting the turbine to the compressor, a fan upstream of the engine core; and a gearbox. The engine core has three bearings, one forward, two rearward, to support the core shaft, a minor span being the axial distance between the two rearward bearings. A first blade to bearing ratio of the minor span divided by the product of the mass, radius at mid-height, and the square of the angular velocity at cruise for a blade of the lowest pressure set may have a value in the range from 2.0×10?6 to 7.5×10?6 kg?1.rad?2.s2. A second blade to bearing ratio of the minor span divided by the product of mass and radius at mid-height for a blade of the lowest pressure set may have a value in the range from 0.8 to 6.0 kg?1.

Abstract: A gas turbine engine for an aircraft includes an engine core with a turbine, a compressor, and a core shaft connecting the two, the turbine and compressor being the lowest pressure turbine and compressor of the engine, the core shaft having a running speed range between 1500 rpm and 6200 rpm; 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 to drive the fan at a lower rotational speed than the core shaft. The engine core includes a forward bearing and two rearward bearings arranged to support the core shaft, and the core shaft having a length between the forward bearing and the rearmost rearward bearing and a minor span between the rearward bearings, and the length ratio of the minor span to the core shaft length is equal to or less than 0.14.

Abstract: An engine core including a turbine, compressor, and core shaft connecting the turbine and compressor, the turbine being the lowest pressure turbine, the core shaft having a running speed range from 1500-6200 rpm, and the compressor being the lowest pressure compressor; a fan located upstream of the engine core; and a gearbox receiving 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, the core shaft having a length between the forward and the rearmost rearward bearing ranging from 1800-2900 mm, and a minor span between two rearward bearings ranging from 250-350 mm, wherein there is no primary resonance of the core shaft between the forward and forwardmost rearward bearing within the running speed range of the core shaft.

Abstract: A fuel flow valve, for example for use in supplying fuel to a gas turbine engine. Example embodiments disclosed include a staging fuel valve (300), comprising: a valve housing (301) having first and second fuel inlets (306, 307) and first and second fuel outlets (305, 308); a piston (302) slidably mounted within a chamber (303) in the valve housing (301) and being moveable between a first position in which the first inlet (306) is in fluid communication with the first outlet (305) while the second inlet (307) and second outlet (308) are blocked, and a second position in which the second inlet (307) is in fluid communication with the second outlet (308). The piston (302) comprises a magnet assembly (312) and the valve housing (301) comprises a coil (313) arranged to provide, when energised, a magnetic force to actuate the piston (302) between the first and second positions.

Abstract: A combustion chamber system has pilot and main fuel manifolds, and pilot and main fuel nozzles. Each pilot nozzle is connected to the pilot manifold. Each main nozzle is connected to the main manifold. A greater total amount of fuel is supplied to the pilot nozzles than to the main nozzles. A greater amount of fuel is supplied to pilot nozzles at, or in, a first region of the combustion chamber than to pilot fuel nozzles at, or in, a second region. A greater amount of fuel is supplied to the main nozzles at, or in, the first region than to the main nozzles at, or in, the second to improve combustion efficiency, weak extinction and relight of the combustion chamber in a first mode of operation. A greater total amount of fuel is supplied to the main nozzles than to the pilot nozzles in a second mode of operation.

Abstract: A fuel spray nozzle comprises a fuel passage (1) having at least one inlet and at least one outlet. The outlet is configured for accelerating fuel exiting the fuel passage into a jet. An air swirler (3) is arranged outboard of the fuel passage and converges to a single outlet chamber (5) adjacent the fuel passage outlet(s). The air swirler (3) can be nominally concentrically arranged but have some freedom to move axially or radially or change its angular position. The fuel passage outlets may be arranged symmetrically in an annular configuration. An air passage may be arranged axially within the annular array of fuel passage outlets.

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: An oil system for a gas turbine engine and a method of supplying oil to the system. The oil system includes a main oil tank connected by oil lines with a supplementary oil storage tank, which has an actuator, and that are connected to one oil pump for supplying oil to the gas turbine engine. The supplementary oil storage tank is equal in size or larger than a steady state oil gulp of the system. The method includes supplying oil from a main oil tank through a pipe line using an oil pump, detecting the oil level in the oil system and determining if additional oil is required or requires removing using a sensor and an electronic controller, and transmitting a signal to an actuator to supply or remove oil to and from the pipe lines in the oil system from or into a supplementary oil storage tank.

Abstract: An aircraft hybrid propulsion system (5) comprises an internal combustion engine (10) comprising a main drive shaft (24), an electric machine (28) comprising an electric machine rotor (78), a propulsor (12) mounted to a propulsor shaft (62), and a clutch arrangement configured to selectively couple each of the gas turbine engine main drive shaft (24) and electric machine rotor (78) to the propulsor drive shaft (62). The electric machine rotor (78) is mounted coaxially with the main drive shaft (24) and the clutch arrangement comprises a first overrunning clutch (52) configured to couple the main drive shaft (24) to the propulsor drive shaft (62), and a second overrunning clutch (54) configured to couple the electric machine rotor (78) to the propulsor drive shaft (62).

Abstract: Electrical machine apparatus comprising: a rotor having an axis of rotation and defining a cavity therein; and a conduit positioned within the cavity of the rotor, the conduit comprising an inlet arranged to receive a fluid and an outlet arranged to exhaust the fluid, the inlet having a first radial distance from the axis of rotation and the outlet having a second radial distance from the axis of rotation, the first radial distance being greater than the second radial distance.

Abstract: There is described a clocking angle setting tool for a wire harness having a support arm provided with a clamp for attaching a harness cable of the wire harness to the support; arm, a connector receptacle for receiving a connector provided at the end of the harness cable and a key or keyway for engaging with a complementary keyway or key of the connector. The connector receptacle is spaced from the clamp and is rotatably mounted to the support arm. A locking mechanism for locking an angular position of the connector receptacle relative to the support arm is included. The angular position of the connector receptacle relative to the support arm determines a clocking angle of the connector relative to the harness cable.

Abstract: A containment arrangement for a gas turbine engine comprises: a radially outer annular casing 12; a fan track liner 28 radially within the casing comprising: an impact region 30 comprising a cellular material having a first compressive strength; at least one elongate ridge portion 26 extending through the impact region in a direction having an axial component, the ridge portion having a second compressive strength higher than the first compressive strength; and a gas-washed layer 38 radially within the fan track liner.

Abstract: A gas turbine engine for an aircraft including: an engine core including a turbine, a compressor, and a core shaft connecting the turbine to the compressor; a fan located upstream of the engine core, the fan including a plurality of fan blades; a gearbox that can receive an input from the core shaft, and can output drive to a fan shaft via an output of the gearbox so as to drive the fan at a lower rotational speed than the core shaft; and a fan shaft mounting structure arranged to mount the fan shaft within the engine, the fan shaft mounting structure including at least two supporting bearings connected to the fan shaft. A fan-gearbox axial distance is defined as the axial distance between the output of the gearbox and the fan axial centreline, the fan-gearbox axial distance being greater than or equal to 0.35 m.

Abstract: An engine core including a turbine, compressor, and a core shaft connecting the turbine and compressor; a fan located upstream of the engine core including a plurality of fan blades; and a gearbox. The gearbox is arranged to receive an input from the core shaft and to output drive to the fan to drive the fan at a lower rotational speed than the core shaft. The gearbox is an epicyclic gearbox and includes a sun gear, a plurality of planet gears, ring gear, and planet carrier to the mounted planet gears. The planet carrier has an effective linear torsional stiffness and the gearbox has a gear mesh stiffness between the planet gears and the ring gear. A carrier to ring mesh ratio of: the ? ? effective ? ? linear ? ? torsional ? ? stiffness ? ? of ? ? the ? ? planet ? ? carrier gear ? ? mesh ? ? stiffness ? ? between ? ? the ? ? planet ? ? gears ? ? and ? ? the ? ? ring ? ? gear is greater than or equal to 0.2.

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 fan blades; and a gearbox. The gearbox receives an input from a core shaft and outputs drive to a fan to drive the fan at a lower rotational speed than the core shaft. The gearbox is an epicyclic gearbox and has a sun gear, planet gears, a ring gear, and a planet carrier on which the planet gears are mounted, the gearbox having an overall gear mesh stiffness. The overall gear mesh stiffness of the gearbox is greater than or equal to 1.05×109 N/m. The gearbox has a gearbox diameter defined as the pitch circle diameter of the ring gear. Optionally, the gearbox diameter is in the range from 0.55 m to 1.2 m.

Abstract: Gas turbine engine for aircraft including: engine core including turbine, compressor, and core shaft connecting turbine to compressor; fan located upstream of engine core, including plurality of fan blades; gearbox receives input from core shaft and outputs drive to fan shaft to drive fan at lower rotational speed than core shaft; and fan shaft mounting structure arranged to mount fan shaft within engine. Fan shaft mounting structure includes at least two supporting bearings connected to fan shaft. Gearbox's output is at gearbox output position and fan's input is at fan input position. First bearing separation distance is defined as axial distance between input to fan and closest bearing of at least two supporting bearings in rearward direction from fan.

Abstract: A gas turbine engine for an aircraft has an engine core having a turbine, compressor, and core shaft connecting the turbine and compressor; a fan upstream the engine core, the fan having fan blades; and a gearbox. The gearbox receives an input from a core shaft and outputs drive to a fan to drive the fan at a lower rotational speed than the core shaft. The gearbox is an epicyclic gearbox and has a sun gear, planet gears, ring gear, and planet carrier on which the planet gears are mounted. The gearbox has a gear mesh stiffness between the planet gears and the ring gear and a gear mesh stiffness between the planet gears and the sun gear. The gear mesh stiffness between the planet gears and the ring gear divided by that between the planet gears and the sun gear is in the range from 0.90 to 1.28.

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 for an aircraft is arranged to receive an input from a core shaft and to output drive to a 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 having a plurality of pins, each pin being arranged to have a planet gear of the plurality of planet gears mounted thereon. A ratio of planet carrier torsional stiffness to pin stiffness is within a specified range.