Abstract: A gear reduction reduces a speed of a fan rotor relative to a speed of a fan drive turbine. A rigid connection between a fan case and an inner core housing includes a plurality of A-frames connected at a connection point to the fan case. Legs in the A-frames extend away from the connection point in opposed circumferential directions to be connected to a compressor wall of the inner core housing. The rigid connection also includes a plurality of fan exit guide vanes rigidly connected to the fan case. A lateral stiffness ratio of the lateral stiffness of the plurality of fan exit guide vanes and a lateral stiffness of a combination of the plurality of A-frame, the compressor wall, and a fan intermediate case which is forward of the low pressure compressor being greater than or equal to 0.6 and less than or equal to 2.0.

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 turbofan engine according to an example of the present disclosure includes, among other things, a fan, a compressor section, a turbine section including a fan drive turbine and a second turbine, an epicyclic gear system with a gear reduction, first and second bearings, and a fan drive shaft interconnecting the gear system and the fan. The fan drive turbine has a first exit area at a first exit point and is rotatable at a first speed. The second turbine has a second exit area at a second exit point and is rotatable at a second speed. A first performance quantity is defined as the product of the first speed squared and the first area. A second performance quantity is defined as the product of the second speed squared and the second area.

Abstract: A fan drive gear system for a turbofan engine according to an exemplary embodiment of this disclosure, among other possible things includes a sun gear that is rotatable about an axis, a plurality of intermediate gears driven by the sun gear, and a baffle that is disposed between at least two of the plurality of intermediate gears for defining a lubricant flow path from an interface between the sun gear and at least one of the plurality of intermediate gears. The baffle includes a channel with at least one ramp portion directing lubricant.

Abstract: A turbofan engine includes a fan section that drives air along a bypass flow path in a bypass duct. An epicyclic gear system in driving engagement with the fan shaft and has a gear mesh lateral stiffness and a gear mesh transverse stiffness. A gear system input to the gear system defines a gear system input lateral stiffness and a gear system input transverse stiffness. The gear system input lateral stiffness is less than 5% of the gear mesh lateral stiffness. A first performance quantity is defined as the product of a first speed squared and a first area and a second performance quantity is defined as the product of a second speed squared and a second area. A performance quantity ratio of a first performance quantity to a second performance quantity is between 0.5 and 1.5.

Abstract: A gas turbine engine includes a propulsor section and a speed change mechanism for driving the propulsor section. The speed change mechanism is an epicyclic gear train. A torque frame includes a ring and a plurality of fingers extending from the ring with the plurality of fingers surrounding the speed change mechanism. A bearing support is attached to the plurality of fingers. A first propulsor section support bearing is mounted on a first axial side of the speed change mechanism and a second propulsor section support bearing is mounted on the bearing support on a second axial side of the speed change mechanism. The second propulsor section support bearing is a propulsor thrust bearing. Each of the plurality of fingers include a pin opening with a pin extending through the pin opening and into the epicyclic gear train.

Abstract: A gas turbine engine includes a propulsor and a fan drive turbine. The fan drive turbine drives the propulsor through a geared architecture. The geared architecture includes a sun gear, a ring gear, and intermediate gears supported on journal support pins. The sun gear engages the intermediate gears and the intermediate gears engages the ring gear. The journal support pins include a titanium body and an outer surface outside of the titanium body that has a surface hardness that is harder than the titanium body. The outer surface is provided by a steel sleeve. Oil supply holes extend from a central bore in the titanium body through the steel sleeve. At least one pin extends through the steel sleeve to secure the steel sleeve to the titanium body.

Abstract: A gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor section including a propulsor, a gear reduction, a first spool including a first compressor, a first turbine and a first shaft, and a second spool including a second compressor, a second turbine and a second shaft. The gear reduction includes a carrier and a plurality of gears. The plurality of gears include a sun gear, a ring gear, and a plurality of intermediate gears that engage the sun gear and the ring gear. At least two of the plurality of gears are double helical gears in meshed engagement.

Abstract: A gas turbine engine includes a fan rotor driven by a fan drive turbine about an axis through a gear reduction. An inner core engine has an inner core engine housing surrounding a compressor section, including a low pressure compressor. A rigid connection between a fan case and the inner core engine includes A-frames rigidly connected at a connection point to the fan case. Fan exit guide vanes rigidly connect to the fan case, and to the inner core engine. A fan intermediate case is positioned forward of a first rotor stage in the low pressure compressor. A rigid structure is connected to the inner core engine and to the fan exit guide vanes. The rigid structure defines a structure moment stiffness. The fan intermediate case defines an intermediate case moment stiffness. A ratio of the structure moment stiffness to the intermediate case moment stiffness is between 5 and 15.

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 turbofan engine according to an example of the present disclosure includes, among other things, a fan, and an outer housing surrounding the fan to define a bypass flow path, a compressor, a turbine section including a fan drive turbine and a second turbine, an epicyclic gear system with a gear reduction, the fan drive turbine driving the fan through the gear system, and the gear system straddle-mounted by first and second bearings. The fan drive turbine has a first exit area at a first exit point and is rotatable at a first speed. The second turbine has a second exit area at a second exit point and is rotatable at a second speed. A first performance quantity is defined as the product of the first speed squared and the first area. A second performance quantity is defined as the product of the second speed squared and the second area.

Abstract: A gear reduction reduces a speed of a fan rotor relative to a speed of a fan drive turbine. A rigid connection between a fan case and an inner core housing includes a plurality of A-frames connected at a connection point to the fan case. Legs in the A-frames extend away from the connection point in opposed circumferential directions to be connected to a compressor wall of the inner core housing. The rigid connection also includes a plurality of fan exit guide vanes rigidly connected to the fan case. A lateral stiffness ratio of the lateral stiffness of the plurality of fan exit guide vanes and a lateral stiffness of a combination of the plurality of A-frame, the compressor wall, and a fan intermediate case which is forward of the low pressure compressor being greater than or equal to 0.6 and less than or equal to 2.0.

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 includes a fan section. A speed change mechanism drives the fan section. The speed change mechanism is an epicyclic gear train. A torque frame includes a ring and a plurality of fingers that extend from the ring with the plurality of fingers surrounding the speed change mechanism. A bearing support is attached to the plurality of fingers. A first fan section support bearing is mounted on a first axial side of the speed change mechanism and a second fan section bearing is mounted on a second axial side of the speed change mechanism. The second fan section bearing is a fan thrust bearing.

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.

Abstract: A disclosed lubrication system for a turbofan engine includes a pump for driving lubricant through a lubrication circuit, at least one sensor generating a signal indicative of an engine operating condition and at least one valve for controlling a flow of lubricant through the lubrication circuit. A controller controls operation of the valve to vary the flow of lubricant based on the engine operating condition to maintain lubricant flow within predefined operating limits.

Abstract: A method of assembling a gear system for a gas turbine engine according to an example of the present disclosure includes the steps of providing a unitary carrier, positioning baffles between side walls of the carrier such that an end of each of the baffles abuts a respective mount of the carrier, inserting intermediate gears through a central opening of the carrier, and then moving the intermediate gears radially outwardly into respective gear pockets of the carrier, inserting a sun gear through the central opening, moving the intermediate gears radially inwardly to engage the sun gear, coupling a shaft to the carrier, including attaching a torque frame to the carrier such that the torque frame interconnects the carrier and the shaft, placing first and second ring gear halves of a ring gear onto an outer periphery of the intermediate gears, and fixedly attaching the ring gear to an engine static structure. A gear system is also disclosed.

Abstract: A gas turbine engine according to an example of the present disclosure includes, among other things, a fan section, a compressor section, and a turbine section 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 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 gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor section including a propulsor supported on a propulsor shaft, a turbine section including a turbine shaft, and an epicyclic gear train interconnecting the propulsor shaft and the turbine shaft. The epicyclic gear train includes a sun gear coupled to the turbine shaft, intermediary gears arranged circumferentially about and meshing with the sun gear, a carrier supporting the intermediary gears, and a ring gear including first and second portions each having an inner periphery with teeth intermeshing with the intermediate gears. The first and second portions have axially opposed faces abutting one another at a radial interface and respective flanges extending along the radial interface radially outward from the teeth. The first and second portions define a trough axially between and separating the teeth of the first portion from the teeth of the second portion.