Abstract: An engine for an aircraft includes 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 an epicyclic gearbox and comprises a sun gear, a plurality of planet gears, a ring gear, and a planet carrier on which the planet gears are mounted. The radial bending stiffness of the planet carrier is equal to or greater than 1.20×109 N/m, and/or the tilt stiffness of the planet carrier is greater than or equal to 6.00×108 Nm/rad. A method of operation of such an engine is also disclosed.

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 shaft component, which in particular can be connected or is connected to the input or output side of a gear box in a gas turbine engine, in particular an aircraft engine, wherein the shaft component has at least two regions comprising fiber reinforced plastic, with fibers in the at least two regions differing in their composition, their geometric properties, their density, their radial position, their axial position and/or in their fiber orientation in the shaft component.

Abstract: A journal bearing comprising a first component and a second component, the first and second components being arranged to rotate relative to one another in normal use. The first component comprises a first body, a first layer forming a functional surface facing the second component, and a first subsurface layer between the body and the layer. The first subsurface layer is formed of a material having a first coefficient of thermal expansion in the radial direction, and the first body is formed of a material having a second coefficient of thermal expansion in the radial direction. The first coefficient of thermal expansion is lower than the second coefficient of thermal expansion.

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 for an aircraft configured with an engine core that has a turbine, a compressor, and a core shaft connecting the turbine to the compressor. A fan located upstream of the engine core, that has a plurality of fan blades. A gearbox arranged to receive an input from the core shaft and to output to the fan so as to drive the fan at a lower rotational speed than the core shaft. The gearbox being an epicyclic gearbox having a sun gear, a plurality of planet gears, a ring gear, and a planet carrier on which the planet gears are mounted. The gearbox having an overall gear mesh stiffness, and wherein the overall gear mesh stiffness of the gearbox is greater than or equal to 1.05×109 N/m and less than or equal to 8.0×109 N/m.

Abstract: An engine for an aircraft includes 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 an epicyclic gearbox and comprises a sun gear, a plurality of planet gears, a ring gear, and a planet carrier on which the planet gears are mounted. The radial bending stiffness of the planet carrier is equal to or greater than 1.20×109 N/m, and/or the tilt stiffness of the planet carrier is greater than or equal to 6.00×108 Nm/rad. A method of operation of such an engine is also disclosed.

Abstract: Gearboxes for aircraft gas turbine engines, in particular to arrangements for journal bearings such gearboxes, and to related methods of operating such gearboxes and gas turbine engines. Example embodiments include a gearbox for an aircraft gas turbine engine, the gearbox including: 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 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: 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: 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: Gearboxes for aircraft gas turbine engines, in particular to arrangements for journal bearings such gearboxes, and to related methods of operating such gearboxes and gas turbine engines. Example embodiments include a gearbox for an aircraft gas turbine engine, the gearbox including: 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: 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: 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: 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: Embodiments of the invention are shown in the figures, where a method for manufacturing a gearbox, the method comprising: providing a predefined interval around an integer; providing a gearbox setup; determining a speed ratio of at least two components of the gearbox setup; comparing the speed ratio with the predefined interval around the integer; and manufacturing a gearbox in accordance with the gearbox setup in dependence on the comparison.

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: A gas turbine engine includes an engine core, a fan and a gearbox interconnecting the engine core and the fan. The engine core is configured to drive rotation of at least one shaft. The power gearbox is configured to transfer torque from the at least one shaft to an output shaft at a reduced rate. The output shaft is coupled to the fan to drive the fan at the reduced rate and provide trust for the gas turbine engine.

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: A gas turbine engine includes an engine core, a fan and a gearbox interconnecting the engine core and the fan. The engine core is configured to drive rotation of at least one shaft. The power gearbox is configured to transfer torque from the at least one shaft to an output shaft at a reduced rotational speed. The output shaft is coupled to the fan to drive the fan at the reduced speed and provide trust for the gas turbine engine.