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 includes an engine core with a turbine, a compressor, and a core shaft connecting the turbine and compressor; a fan upstream of the engine core including a plurality of fan blades; and a gearbox that receives an input from a gearbox input shaft portion of the core shaft and outputs drive to a fan shaft so as to drive the fan at a lower rotational speed than the core shaft, the gearbox being an epicyclic gearbox including a sun gear, a plurality of planet gears, a ring gear, and a planet carrier arranged to have the plurality of planet gears mounted thereon, and wherein the sun gear receives input from the core shaft. At cruise conditions the torque on the core shaft is greater than 10,000 Nm and a ratio of core shaft stiffness to core shaft torque is within a specified range.

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: Gas turbine engine for aircraft includes: an engine core including a turbine, compressor, and core shaft; a fan located upstream of the core; and a gearbox for receiving input from the core shaft, and outputting drive to a fan shaft via an output of the gearbox. A fan-gearbox axial distance is an axial distance between an axial position of the gearbox output position and the fan axial centreline. The fan-gearbox axial distance multiplied by a moment of inertia of the fan may range from 1.9×107 kgmm2m to 6.2×108 kgmm2m and/or the fan-gearbox axial distance divided by a moment of inertia of the fan may range from 5.3×10?10 m/kgmm2 to 8.8×10?9 m/kgmm2. A product of: (the radial bending stiffness of the fan shaft at the output of the gearbox)×(the moment of inertia of the fan) may be range from 2.0×1014 Nkgmm2m?1 to 1.4×1018 Nkgmm2m?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: A hybrid transmission component includes a composite tube defining a central axis along its length and extending between a first end and a second end opposite to the first end. The composite tube includes a tube inner surface extending circumferentially about the central axis and a tube outer surface that is radially spaced apart from the tube inner surface with respect to the central axis. The composite tube further includes a first tube axial end surface extending between the tube inner surface and the tube outer surface at the first end and a second tube axial end surface extending between the tube inner surface and the tube outer surface at the second end. The tube inner surface comprises a wedge portion disposed at the first end.

Abstract: A composite gear includes an annular metallic gear hub including a bore and defining a central axis. The composite gear includes a composite web disposed circumferentially around the annular metallic gear hub with respect to the central axis. It includes a metallic gear rim disposed circumferentially around the composite web with respect to the central axis. The metallic gear rim includes an annular portion disposed adjacent to the composite web and a plurality of gear teeth angularly spaced apart from each other and extending outwardly from the annular portion distal to the composite web. The composite gear includes an interface disposed between the metallic gear rim and the composite web. The composite web includes a plurality of fibres inclined against each other by an angle from 30 to 60 degrees in order to form a mesh or woven fabric.

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, including 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.

Abstract: A shaft for a gas turbine engine includes a composite tube including a plurality of grooves extending along a longitudinal axis of the shaft. The shaft has a load fuse mechanism that has at least one metallic coupling that has a plurality of splines extending along the longitudinal axis of the shaft. Each of the plurality of splines is received within and engages with a corresponding groove of the composite tube to form a preloaded interference fit between the load fuse mechanism and the composite tube. The at least one metallic coupling includes a first portion defining a first diameter and a second portion extending from the first portion along the longitudinal axis. The second portion defines a second diameter that is greater than the first diameter. The second portion has a smooth annular outer surface devoid of any splines.

Abstract: A hybrid transmission component for a gas turbine engine has a composite body, and a metallic coupling joined with the composite body and defining a longitudinal axis along its length. The metallic coupling includes a plurality of spline teeth extending from a circumferential surface and angularly separated from each other about the longitudinal axis. Each spline tooth from the plurality of spline teeth extends radially from a root to a tip with respect to the longitudinal axis and extends axially from the leading end along the longitudinal axis. The leading end of each spline tooth includes a curved surface extending from the root and a planar surface extending from the curved surface to the tip. The planar surface is inclined obliquely to the longitudinal axis by a rake angle.

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, including 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: 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.

Abstract: Gas turbine engine for aircraft includes: an engine core including a turbine, compressor, and core shaft connecting the turbine to the compressor; a fan located upstream of the core; a gearbox; and a gearbox support arranged to at least partially support the gearbox. The fan has a mass in a range of 150 kg to 1200 kg. A moment of inertia of the fan is greater than or equal to 7.40×107 kgmm2. A radial bending stiffness to moment of inertia ratio of: the ? radial ? bending ? stiffness ? of ? at ? least ? one ? of ? the ? fan ? shaft at ? the ? output ? of ? the ? gearbox ? and ? the ? gearbox ? support the ? moment ? of ? inertia ? of ? the ? fan may be greater than or equal to 2.5×10?2 Nkg?1m?1mm?2.

Abstract: Gas turbine engine for aircraft includes: an engine core including a turbine, compressor, and core shaft connecting the turbine to the compressor; a fan located upstream of the core; a gearbox; and a gearbox support arranged to at least partially support the gearbox. The fan has a mass in a range of 150 kg to 1200 kg. A moment of inertia of the fan is greater than or equal to 7.40×107 kgmm2. A radial bending stiffness to moment of inertia ratio of: the ? radial ? bending ? stiffness ? of ? at ? least ? one ? of ? the ? fan ? shaft ? at ? the ? output ? of ? the ? gearbox ? and ? the ? gearbox ? support the ? moment ? of ? inertia ? of ? the ? fan may be greater than or equal to 2.5×10?2 Nkg?1m?1mm?2.

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 comprising an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor. A fan located upstream of the engine core, the fan comprising a plurality of fan blades and having a fan diameter and a gearbox arranged to receive an input from 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, thereby defining a gear ratio. The gearbox being an epicyclic gearbox. A gearbox diameter is defined as the pitch circle diameter of the ring gear; and a geared-fan value defined by a product of the fan diameter and gear ratio, which are divided by the gearbox diameter, being greater than 12.

Abstract: A shaft for a gas turbine engine includes a composite tube including a plurality of grooves extending along a longitudinal axis of the shaft. The shaft has a load fuse mechanism that has at least one metallic coupling that has a plurality of splines extending along the longitudinal axis of the shaft. Each of the plurality of splines is received within and engages with a corresponding groove of the composite tube to form a preloaded interference fit between the load fuse mechanism and the composite tube. The at least one metallic coupling includes a first portion defining a first diameter and a second portion extending from the first portion along the longitudinal axis. The second portion defines a second diameter that is greater than the first diameter. The second portion has a smooth annular outer surface devoid of any splines.

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.