Abstract: A gas turbine engine according to an example of the present disclosure includes, among other things, a fan, a compressor, a combustor, and a spool including a fan drive turbine that drives the fan through a gear reduction. The gear reduction includes at least two double helical gears in meshed engagement, each of the at least two double helical gears having a first plurality of gear teeth separated from a second plurality of gear teeth such that a first end of the first plurality of gear teeth and a first end of the second plurality of gear teeth are spaced apart by an axial distance. Each of the first plurality of gear teeth is offset a first circumferential offset distance in relation to the next gear tooth of the second plurality of gear teeth when moving in a circumferential direction relative to respective axes.

Abstract: A gas turbine engine according to an example of the present disclosure includes, among other things, a fan shaft configured to drive a fan, a support configured to support at least a portion of the fan shaft, the support defining a support transverse stiffness and a support lateral stiffness, a gear system coupled to the fan shaft, and a flexible support configured to at least partially support the gear system. The flexible support defines a flexible support transverse stiffness with respect to the support transverse stiffness and a flexible support lateral stiffness with respect to the support lateral stiffness. The input defines an input transverse stiffness with respect to the support transverse stiffness and an input lateral stiffness with respect to the support lateral stiffness.

Abstract: A method of assembling an epicyclic gear train includes providing a unitary carrier that includes spaced apart walls and circumferentially spaced mounts interconnecting the walls, spaced apart apertures provided between the mounts at an outer circumference of the carrier, gear pockets provided between the walls and mounts extending to the apertures, and a central opening in at least one of the walls, inserting an intermediate gear through the central opening and moving the intermediate gear radially into the gear pocket to extend through the aperture, inserting a baffle into the carrier, and inserting a sun gear through the central opening to intermesh with the intermediate gear.

Abstract: A gas turbine engine includes a bypass ratio greater than about ten (10). A fan is supported on a fan shaft and has a plurality of fan blades. A gear system is connected to the fan shaft and a plurality of planetary gears. A first set of opposed angled ring gear teeth are separated from a second set of opposed angled ring gear teeth. A lubricant flow path is located axially between the first set of opposed angled ring gear teeth and the second set of opposed angled ring gear teeth. An annular channel axially is aligned with the lubricant flow path. A low pressure turbine has an inlet, an outlet, and a low pressure turbine pressure ratio greater than 5:1. A low fan pressure ratio is less than 1.45 across the fan blade alone.

Abstract: An epicyclic gear train for a gas turbine engine according to an example of the present disclosure includes, among other things, a gutter having an annular channel, a sun gear rotatable about an axis, intermediary gears arranged circumferentially about and meshing with the sun gear, a carrier supporting the intermediary gears, and a ring gear arranged about and intermeshing with the intermediary gears, the ring gear having an aperture axially aligned with the annular channel. The ring gear includes axially spaced apart walls that extend radially outward to define a passageway, and the passageway is arranged radially between the aperture and the annular channel such that the walls inhibit an axial flow of an oil passing from the aperture toward the annular channel.

Abstract: A method of assembling an epicyclic gear train according to an example of the present disclosure includes, among other things, the steps of providing a carrier having a central axis that includes spaced apart side walls and circumferentially spaced connecting structure defining mounts that interconnect the side walls, spaced apart apertures provided at an outer circumference of the carrier, gear pockets provided between the side walls and extending to the apertures, and a central opening in at least one of the walls, providing oil baffles between the side walls, the oil baffles including ends that abut the mounts, inserting a plurality of intermediate gears through the central opening, and then moving the intermediate gears radially outwardly into the gear pockets to extend into the apertures, inserting a sun gear through the central opening, and moving the plurality of intermediate gears radially inwardly to engage the sun gear.

Abstract: A method of assembling a fan drive gear system for a gas turbine engine according to an example of the present disclosure includes the steps of providing a unitary carrier defining a central axis and that includes spaced apart walls and circumferentially spaced mounts defining spaced apart apertures at an outer circumference of the carrier, gear pockets defined between the walls and extending to the apertures, and a central opening in at least one of the walls. The method includes the steps of inserting a plurality of intermediate gears through the central opening, moving the intermediate gears radially outwardly relative to the central axis into the gear pockets, inserting a sun gear through the central opening, moving the plurality of intermediate gears radially inwardly relative to the central axis to engage the sun gear, and coupling a fan shaft to the carrier such that the fan shaft and intermediate gears are rotatable about the central axis. A fan drive gear system is also disclosed.

Abstract: A gas turbine engine includes a fan shaft that drives a fan that has fan blades. An outer housing surrounds the fan. A bypass flow path is within the outer housing. A fan shaft support that supports the fan shaft defines a fan shaft support transverse stiffness. A gear system is connected to the fan shaft. The gear system includes a gear mesh that defines a gear mesh transverse stiffness. A flexible support which supports the gear system relative to a static structure defines a flexible support transverse stiffness. The flexible support transverse stiffness is less than 11% of the fan shaft support transverse stiffness. The flexible support transverse stiffness is less than 8% of the gear mesh transverse stiffness.

Abstract: An exemplary gas turbine engine includes a fan section including a fan rotor and at least one fan blade. A fan pressure ratio across the at least one fan blade is less than 1.45, noninclusive of the pressure across any fan exit guide vane system. The engine further includes a low-pressure compressor having a low-pressure compressor rotor that rotates together with the fan rotor at a common speed in operation, and a geared architecture that drives the low-pressure compressor rotor and the fan rotor. The geared architecture has a gear reduction ratio of greater than 2.5. The engine further includes a high-pressure compressor having a pressure ratio greater than 20, a low-pressure turbine having a pressure ratio greater than 5, and a bypass ratio greater than 10.

Abstract: A gas turbine engine has a fan drive turbine driving a gear reduction, the gear reduction, in turn, driving a fan rotor, the fan rotor delivering air into a bypass duct as bypass air and into a compressor section as core flow. A forward bearing is positioned between the gear reduction and the fan rotor and supports the gear reduction. A second bearing is positioned aft of the gear reduction and supports the gear reduction. The second bearing is a thrust bearing. A fan drive turbine drive shaft drives the gear reduction. The fan drive turbine drive shaft has a weakened link which is aft of the second bearing such that the fan drive turbine drive shaft will tend to fail at the weakened link, and at a location aft of the second bearing.

Abstract: A gearbox assembly for a gas turbofan engine includes a sun gear rotatable about an axis and a plurality of intermediate gears driven by the sun gear. A baffle disposed between at least two of the plurality of intermediate gears includes a first gap distance within a first gap portion and a second gap distance within a second gap portion. The first gap portion is disposed between the baffle and one of the intermediate gears away from the meshed interface with the sun gear and the second gap portion is disposed near the interface with the sun gear. The first gap distance within the first gap portion is different than the second gap distance within the second gap portion to define a desired lubricant flow path.

Abstract: A gas turbine engine may include a high speed spool, a low speed spool, a first epicyclic gear system, and a second epicyclic gear system. Generally, the high speed spool mechanically connects a high pressure turbine to a high pressure compressor, and the low speed spool mechanically connects a low pressure turbine to at least one of a fan and a prop via the first epicyclic gear system and to a low pressure compressor via the second epicyclic gear system, according to various embodiments. The first epicyclic gear system and the second epicyclic gear system may include a common sun gear shaft.

Abstract: A turbofan engine includes a fan that delivers air into a bypass duct and into a core engine. A fan drive gear system includes a gear carrier and at least one ring gear. The at least one ring gear is coupled to an engine case of the turbofan engine with a compliant flexure. A fan shaft couples the gear carrier in the fan drive gear system to the fan. A first bearing is forward of the fan drive gear system and supports the fan drive gear system. A second bearing is aft of the fan drive gear system and supports the fan drive gear system.

Abstract: A gear includes a multiple of gear teeth that extend from an outer portion of a rim about an axis and an inner portion of the rim about the axis, the inner portion of the rim additive manufactured.

Abstract: A gas turbine engine includes a core engine, a fan section, and a superposition gearbox that includes a sun gear. A plurality of intermediate gears are engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. The core engine drives the sun gear and an output from the superposition gearbox driving the fan section. An electric motor is coupled to a portion of the superposition gearbox to provide a portion of power to drive the fan section through the superposition gearbox.

Abstract: A geared architecture for a gas turbine engine includes a fan shaft driving a fan surrounded by an outer housing. A frame that supports the fan shaft and defines a frame lateral stiffness. A plurality of gears are in driving engagement with the fan shaft. The plurality of gears provide an epicyclic gear system which includes a gear mesh defining a gear mesh lateral stiffness and a ring gear defining a ring gear lateral stiffness. The ring gear lateral stiffness is less than 12% of the gear mesh lateral stiffness. A flexible support supports the epicyclic gear system relative to a static structure and defines a flexible support lateral stiffness and a flexible support transverse stiffness. An input coupling to the plurality of gears defines an input coupling lateral stiffness. The flexible support lateral stiffness and the input coupling lateral stiffness are each less than about 11% of said frame lateral stiffness.

Abstract: A method of designing a gas turbine engine includes configuring a speed reduction device for driving a fan and configuring a lubrication system for lubricating components across a rotation gap. The lubrication system includes a lubricant input. A stationary first bearing receives lubricant from the lubricant input and has a first race in which lubricant flows. A second bearing for rotation is within the first bearing. The second bearing has a first opening in registration with the first race such that lubricant may flow from the first race through the first opening into a first conduit. The first bearing is configured to also include a second race into which lubricant flows. The second bearing has a second opening in registration with the second race such that lubricant may flow from the second race through the second opening into a second conduit. The first and second conduits deliver lubricant to distinct locations.

Abstract: A method of designing a gas turbine engine includes configuring a speed reduction device for driving a fan and configuring a lubrication system for lubricating components across a rotation gap. The lubrication system includes a lubricant input. A stationary first bearing receives lubricant from the lubricant input and has a first race in which lubricant flows. A second bearing for rotation is within the first bearing. The second bearing has a first opening in registration with the first race such that lubricant may flow from the first race through the first opening into a first conduit. The first bearing is configured to also include a second race into which lubricant flows. The second bearing has a second opening in registration with the second race such that lubricant may flow from the second race through the second opening into a second conduit. The first and second conduits deliver lubricant to distinct locations.

Abstract: A gas turbine engine installed on an aircraft includes a fan rotor, a turbine rotor, a gearbox, an auxiliary pump, and an electric motor. The gearbox couples the fan rotor to the turbine rotor, the turbine rotor being adapted to drive the fan rotor via the gearbox. The auxiliary pump is configured to circulate lubricating fluid in an auxiliary lubrication system and supplies the gearbox. The electric motor is configured to receive electricity when the aircraft is parked an adapted to drive the auxiliary pump such that the auxiliary pump circulates lubricating fluid while the aircraft is parked.

Abstract: A journal support pin to support intermediate gears for use in gas turbine engine comprises a titanium body, and an outer surface outside of the titanium body having a surface hardness that is harder than the body. A gas turbine engine and a method of forming a journal support pin to support intermediate gears for use in gas turbine engine are also disclosed.