Abstract: A gear train comprising: an input shaft; a first sun gear coupled to the input shaft; a plurality of first planet gears engaging the first sun gear; a first ring gear engaging the plurality of first planet gears; and a first planet carrier coupled to the plurality of first planet gears; a second sun gear coupled to the input shaft; a plurality of second planet gears engaging the second sun gear; a second ring gear engaging the plurality of second planet gears; and a second planet carrier coupled to the plurality of second planet gears; and an output member coupled to the first planet carrier at a first torque transfer location and coupled to the second planet carrier at a second torque transfer location, different to the first torque transfer location.

Abstract: A fluid conduit for a gas turbine engine. The conduit includes a superelastic material such as TNTZ or Ti2448. The conduit is installed such that at least part of the conduit is subject to a stress which lies in one of a superelastic and a plastic region of the material in use.

Abstract: A method of determining the axial load on load-sharing thrust bearings including: providing first and second thrust bearings, each including an inner race and an outer race supported by at least one resilient element; applying a test axial load to each of the first and second thrust bearings to elastically deform the at least one resilient element so as to axially displace the outer race; determining the test axial displacement of each outer race to obtain calibration data comprising values of axial load versus axial displacement; applying an in-service axial load to the first and second thrust bearings to elastically deform the resilient elements so as to axially displace the respective outer races; measuring the in-service axial displacement of each outer race; and based on the measured in-service axial displacements, inferring from the calibration data the values of the in-service axial loads on the first and second thrust bearings.

Abstract: A bearing arrangement includes: first and second thrust bearings, arranged on a shaft and including respective first and second pressure faces; and a hydraulic connection, connecting the first and second thrust bearings and having a non-compressible fluid. Applying a shaft thrust load axially moves the first thrust bearing so that the first pressure face displaces the non-compressible fluid from the first thrust bearing to the second thrust bearing so as to apply a reaction force to the second pressure face, in order that the thrust load is shared between the first and second thrust bearings.

Abstract: A gas turbine engine variable area exhaust nozzle has a plurality of first and second movable members arranged circumferentially around a fan casing extending in downstream. The first and second movable members alternate around the variable area nozzle. During cruise conditions the first and second movable members are in un-actuated positions. At take off conditions the first movable members are in an actuated position and the second movable members are in the un-actuated position. At top of climb conditions the first movable members are in the un-actuated position and the second movable members are in an actuated position. The first movable members move radially outwardly from the un-actuated position to the actuated position and the second movable members move radially inwardly from the un-actuated position to the actuated position.

Abstract: A gear train comprising: an input shaft; a first sun gear coupled to the input shaft; a plurality of first planet gears engaging the first sun gear; a first ring gear engaging the plurality of first planet gears; and a first planet carrier coupled to the plurality of first planet gears; a second sun gear coupled to the input shaft; a plurality of second planet gears engaging the second sun gear; a second ring gear engaging the plurality of second planet gears; and a second planet carrier coupled to the plurality of second planet gears; and an output member coupled to the first planet carrier at a first torque transfer location and coupled to the second planet carrier at a second torque transfer location, different to the first torque transfer location.

Abstract: A bearing arrangement is disclosed. The bearing arrangement includes first and second bearings, with each bearing including a respective support element and a respective set of rolling elements and defining a respective load path extending through the respective support element and rolling elements. The support elements are coupled such that a load applied to either support element is transmitted through both the first and second load paths. The arrangement further includes a pair of superelastic titanium alloy elements located in the respective load paths to provide resilient movement between the bearings when a load is applied to the bearing arrangement.

Abstract: A method of determining the axial load on load-sharing thrust bearings including: providing first and second thrust bearings, each including an inner race and an outer race supported by at least one resilient element; applying a test axial load to each of the first and second thrust bearings to elastically deform the at least one resilient element so as to axially displace the outer race; determining the test axial displacement of each outer race to obtain calibration data comprising values of axial load versus axial displacement; applying an in-service axial load to the first and second thrust bearings to elastically deform the resilient elements so as to axially displace the respective outer races; measuring the in-service axial displacement of each outer race; and based on the measured in-service axial displacements, inferring from the calibration data the values of the in-service axial loads on the first and second thrust bearings.

Abstract: A bearing arrangement comprises: first and second thrust bearings, each including an inner race which is disposed on a shaft and an outer race which is supported by at least one resilient element. Applying a shaft thrust load elastically deforms the resilient elements so as to axially displace the respective outer races in order that the thrust load is shared between the first and second thrust bearings.

Abstract: A fluid conduit for a gas turbine engine. The conduit includes a superelastic material such as TNTZ or Ti2448. The conduit is installed such that at least part of the conduit is subject to a stress which lies in one of a superelastic and a plastic region of the material in use.

Abstract: A bearing arrangement comprises: first and second thrust bearings, each including an inner race which is disposed on a shaft and an outer race which is supported by at least one resilient element. Applying a shaft thrust load elastically deforms the resilient elements so as to axially displace the respective outer races in order that the thrust load is shared between the first and second thrust bearings.

Abstract: A bearing arrangement includes: first and second thrust bearings, arranged on a shaft and including respective first and second pressure faces; and a hydraulic connection, connecting the first and second thrust bearings and having a non-compressible fluid. Applying a shaft thrust load axially moves the first thrust bearing so that the first pressure face displaces the non-compressible fluid from the first thrust bearing to the second thrust bearing so as to apply a reaction force to the second pressure face, in order that the thrust load is shared between the first and second thrust bearings.

Abstract: A duct arrangement 18 for a waterjet propulsor 10. The duct arrangement 18 comprises a main duct 30 having an inlet 20. The inlet 20 has an elongate main portion 32 extending along a principal axis 34, and at least one lateral portion 36 in fluid communication with the main portion 34. The at least one lateral portion 36 extends part way only along the length of the main portion 34.

Abstract: A bearing arrangement is disclosed. The bearing arrangement includes first and second bearings, with each bearing including a respective support element and a respective set of rolling elements and defining a respective load path extending through the respective support element and rolling elements. The support elements are coupled such that a load applied to either support element is transmitted through both the first and second load paths. The arrangement further includes a pair of superelastic titanium alloy elements located in the respective load paths to provide resilient movement between the bearings when a load is applied to the bearing arrangement.

Abstract: A duct arrangement 18 for a waterjet propulsor 10. The duct arrangement 18 comprises a main duct 30 having an inlet 20. The inlet 20 has an elongate main portion 32 extending along a principal axis 34, and at least one lateral portion 36 in fluid communication with the main portion 34. The at least one lateral portion 36 extends part way only along the length of the main portion 34.

Abstract: An exhaust nozzle 234 comprising inner and outer walls defined by a turbine casing 233 and a nacelle 230 respectively. A duct in the form of a bypass duct 232 is defined therebetween through which a bypass flow B flows in use. The nacelle 230 comprises a fixed upstream wall section 240 and at least one radially movable downstream wall section 242. At least one closure element in the form of a first slat 248 is provided, which is locatable across the second outlet 246 extending in a generally axial direction. A downstream end 250 of the first slat 248 is radially moveable between an open position in which the second outlet 246 is open, and a closed position in which the second outlet 246 is closed.

Abstract: A gas turbine engine variable area exhaust nozzle has a plurality of first and second movable members arranged circumferentially around a fan casing extending in downstream. The first and second movable members alternate around the variable area nozzle. During cruise conditions the first and second movable members are in un-actuated positions. At take off conditions the first movable members are in an actuated position and the second movable members are in the un-actuated position. At top of climb conditions the first movable members are in the un-actuated position and the second movable members are in an actuated position. The first movable members move radially outwardly from the un-actuated position to the actuated position and the second movable members move radially inwardly from the un-actuated position to the actuated position.

Abstract: A gas turbine engine variable area exhaust nozzle has a plurality of first and second movable members arranged circumferentially around a fan casing extending in downstream. The first and second movable members alternate around the variable area nozzle. During cruise conditions the first and second movable members are in un-actuated positions. At take off conditions the first movable members are in an actuated position and the second movable members are in the un-actuated position. At top of climb conditions the first movable members are in the un-actuated position and the second movable members are in an actuated position. The first movable members move radially outwardly from the un-actuated position to the actuated position and the second movable members move radially inwardly from the un-actuated position to the actuated position.

Abstract: In a turbofan gas turbine engine, a fan shaft is rotatably mounted and radially supported by a bearing in a bearing support structure-supported from a fixed engine structure by radially frangible bolts and radially extending spokes. The radially inner ends of the radially extending spokes are mounted on a common member that engages the bearing support structure. The radially outer ends of the radially extending spokes are mounted on fixed structure of the engine located radially outwardly of the bearing support structure. The radially extending spokes are held in tension and include a super elastic material to exert a radially inward restoring force on the bearing support structure, subsequent to any radial excursion of at least part of the fan shaft relative to an engine rotational axis (X) following any fracture of the frangible bolts.

Abstract: In a turbofan gas turbine engine, a fan shaft is rotatably mounted and radially supported by a bearing in a bearing support structure supported from a fixed engine structure by radially frangible bolts and radially extending spokes. The radially inner ends of the radially extending spokes are mounted on a common member that engages the bearing support structure. The radially outer ends of the radially extending spokes are mounted on a fixed engine structure located radially outwardly of the bearing support structure. The radially extending spokes are held in tension and include a super elastic material to exert a radially inward restoring force on the bearing support structure, subsequent to any radial excursion of at least part of the fan shaft relative to an engine rotational axis (X) following any fracture of the frangible bolts.