Abstract: An epicyclic gearing arrangement includes a planet gear rotatable on a planet bearing that is mounted via a support pin to a carrier of the epicyclic gearing arrangement. A spring film damper is disposed between the cylindrical outer surface of the support pin and the opposing inner surface of the inner ring of the planet bearing and includes an annular gap.

Abstract: A planet gear train for an engine casing includes a sun gear rotatable by a shaft, a ring gear, a plurality of planet gears rotatably mounted in a planet carrier and meshing with the sun gear and the ring gear, and a damping system. The damping system includes a soft mount disposed about the shaft and coupling the planet carrier the engine casing. The soft mount includes a flexible inner sleeve and a flexible outer sleeve. The flexible inner sleeve and the flexible outer sleeve are fixedly coupled together at respective central portions thereof near the shaft. The damping system further includes a plurality of damping couplers disposed about an outer flange of the planet carrier. The plurality of damping couplers is configured to flexibly couple the flexible inner sleeve to the flexible outer sleeve.

Abstract: Embodiments of a compliant shaft for engines are provided herein. In some embodiments, a compliant shaft for a turbine engine may include: a body having a first end configured to be coupled to a shaft of a turbine and a second end coupled to a gear of a gear box, wherein at least a portion of the body is flexible.

Abstract: A planet gear includes a pin and an annular planet gear rim. The pin has a pin radius. The pin includes a pin outer surface. The annular planet gear rim has an inner radius and an outer radius. The annular planet gear rim includes an inner surface and an outer surface. The inner surface and the pin outer surface define a clearance therebetween. The clearance is greater than 0 when a radial force is applied to the planet gear.

Abstract: A lubrication system for a gas turbine engine includes a tank, a circulation pump, and a heat exchanger. The circulation pump generates a flow of lubricant from the tank to, e.g., a power gear box of the gas turbine engine and the heat exchanger removes an amount of heat from such flow of lubricant provided to the power gear box. The lubrication system also includes one or more valves in the flow of lubricant for controlling a flowrate and/or temperature of the lubricant provided to, e.g., the power gear box to increase an efficiency and/or durability of the power gear box.

Abstract: A gas turbine engine includes a fan section and a core turbine engine. The fan section includes a fan and a fan shaft, with the fan including a plurality fan blades rotatable with the fan shaft. The core turbine engine includes a turbine section having a first turbine and a second turbine. The core turbine engine additionally includes a spool rotatable with the second turbine. An epicyclic power gearbox is also provided including a sun gear rotatable with the spool, a ring gear, and a total of four or less planet gears engaged between the sun gear and the ring gear. The power gearbox is configured such that a fan pressure ratio defined by the fan is greater than about 1.05 and less than about 1.50 during operation of the gas turbine engine.

Abstract: A lubrication system for a gas turbine engine includes a tank, a circulation pump, and a heat exchanger. The circulation pump generates a flow of lubricant from the tank to, e.g., a power gear box of the gas turbine engine and the heat exchanger removes an amount of heat from such flow of lubricant provided to the power gear box. The lubrication system also includes one or more valves in the flow of lubricant for controlling a flowrate and/or temperature of the lubricant provided to, e.g., the power gear box to increase an efficiency and/or durability of the power gear box.

Abstract: A pitch control mechanism includes: a rotor structure configured for rotation about a longitudinal axis; a row of blades carried by the rotor structure, each blade having an airfoil and a trunnion mounted for pivoting movement relative to the rotor structure, about a trunnion axis which is perpendicular to the longitudinal axis; a unison ring interconnecting the blades; an actuator connected to the unison ring and the rotor structure, operable to move the unison ring relative to the rotor structure; at least one moveable counterweight carried by the rotor structure, remote from the blades; and an interconnection between the blades and the counterweight, such that movement of the counterweight causes a change in the pitch angle of the blades.

Abstract: An epicyclic gearing arrangement includes a planet gear rotatable on a planet bearing that is mounted via a support pin to a carrier of the epicyclic gearing arrangement. A spring film damper is disposed between the cylindrical outer surface of the support pin and the opposing inner surface of the inner ring of the planet bearing and includes an annular gap.

Abstract: An epicyclic gearing arrangement includes a planet gear rotatable on a planet bearing that is mounted via a support pin to a carrier of the epicyclic gearing arrangement. A spring film damper is disposed between the outer surface of the bearing's outer ring and the opposing inner surface of the planet gear and includes an annular gap. The support pin and/or outer ring include oil feed holes that open into the respective annular gap(s).

Abstract: A planet gear includes an annular planet gear ring including an annular planet gear rim. The annular planet gear rim has an inner radius and an outer radius. The inner radius and the outer radius define a rim thickness therebetween. The annular planet gear rim further has a bending stress neutral axis. The bending stress neutral axis radius and the rim thickness define a ratio including values in a range from and including about 3 to and including about 10.

Abstract: An epicyclic gearing arrangement includes a planet gear rotatable on a planet bearing that is mounted via a support pin to a carrier of the epicyclic gearing arrangement. An attenuation spring is disposed between the outer surface of the bearing's outer ring and the opposing inner surface of the planet gear and includes an annular gap. A spring film damper is disposed between the cylindrical outer surface of the support pin and the opposing inner surface of the inner ring of the planet bearing and includes an annular gap. The support pin (96) and/or outer ring include oil feed holes that open into the respective annular gap(s). A gas turbine engine includes an epicyclic gearing arrangement having such a planet bearing.

Abstract: Embodiments of a compliant shaft for engines are provided herein. In some embodiments, a compliant shaft for a turbine engine may include: a body having a first end configured to be coupled to a shaft of a turbine and a second end coupled to a gear of a gear box, wherein at least a portion of the body is flexible.

Abstract: A casing for use in a turbofan engine is provided. The casing includes an inner hub, an intermediate casing positioned radially outward from the inner hub, an outer casing positioned radially outward from the intermediate casing, and a plurality of struts spaced circumferentially about the inner hub and extending between the inner hub and the outer casing. At least one strut of the plurality of struts includes a flow channel extending therethrough. The casing also includes a fluid scoop defined within the inner hub, and a collector that couples the fluid scoop in flow communication with the flow channel.

Abstract: A planet gear train for an engine casing includes a sun gear rotatable by a shaft, a ring gear, a plurality of planet gears rotatably mounted in a planet carrier and meshing with the sun gear and the ring gear, and a damping system. The damping system includes a soft mount disposed about the shaft and coupling the planet carrier the engine casing. The soft mount includes a flexible inner sleeve and a flexible outer sleeve. The flexible inner sleeve and the flexible outer sleeve are fixedly coupled together at respective central portions thereof near the shaft. The damping system further includes a plurality of damping couplers disposed about an outer flange of the planet carrier. The plurality of damping couplers is configured to flexibly couple the flexible inner sleeve to the flexible outer sleeve.

Abstract: A static lubricant supply system within a gearbox that delivers lubricant to rotating gears. The lubricant supply system includes a stationary sleeve assembly for delivering the lubricant to a rotating receiver member, shaft, or flange. The sleeve assembly includes bearings, seals, jets, and plenums. The jets are skewed to deliver lubricant in the tangential direction of rotational motion of the receiver member, shaft, or flange. In the radial gap transfer configuration, the sleeve assembly circumscribes the receiver member or shaft. A race in the receiver member or shaft receives the lubricant. Channels within the receiver member, shaft, and gears deliver lubricant to the gears. In the axial gap transfer configuration, the sleeve assembly transfers lubricant to a flange attached to a receiver member. The flange has a race that receives the lubricant from the jets. Channels within the flange, receiver member, and gears deliver lubricant to the gears.

Abstract: A planet gear rotatable on a planet bearing with cylindrical rollers is mounted to a carrier of an epicyclic gearing arrangement. Either the cylindrical outer surface of the support pin or the opposing cylindrical inner surface of the inner ring of the planet bearing includes a network of interconnected grooves. The support pin includes oil feed holes intersecting the grooves. Passages through the planet bearing's inner ring also connect to the grooves. A gas turbine engine includes a fan and LP shaft, which couples a compressor to a turbine. An epicyclic gearing arrangement has a single input from the LP shaft coupled to a sun gear, a single output coupled to the fan's shaft, and a planet bearing with a network of interconnected grooves.

Abstract: A planet gearbox is provided for connection to a carrier of an epicyclic gearing arrangement with a single input and single output and including a sun gear, a ring gear and at least one double helix planet gear rotatable on a cylindrical roller bearing with a cage having a cross-web thickness of 15% to 25% of the diameter of the cylindrical rollers and an L/D ratio exceeding 1.0. A gas turbine engine includes a fan and LP shaft, which couples a compressor to a turbine. An epicyclic gearing arrangement has a single input from the LP shaft coupled to a sun gear, a single output coupled to the fan's shaft, and a planet bearing cage having a cross-web thickness measuring 15% to 25% of the roller's diameter.

Abstract: A planet gearbox is provided for connection to a carrier of an epicyclic gearing arrangement with a single input and single output and including a sun gear, a ring gear and at least one double helix planet gear rotatable on a cylindrical roller bearing wherein the ratio of each cylindrical roller's length to each cylindrical roller's diameter exceeds 1.0. A gas turbine engine includes a shaft coupling a compressor of a compressor section to a turbine of a turbine section. An epicyclic gearing arrangement has a single input from the shaft coupled to a sun gear, a single output from the carrier that is coupled to the shaft of a fan and includes a planet gearbox with cylindrical rollers having a length-to-diameter ratio exceeding 1.0.

Abstract: A gas turbine engine including a fan, a core including at least one rotatable shaft, and a gearbox mechanically coupling at least one rotatable shaft of the core to the fan is provided. The gas turbine engine also includes a coupling system for mounting the gearbox within the gas turbine engine. The coupling system includes a flexible coupling connected to at least one of a fan frame or a core frame, as well as a torque frame connected to the flexible coupling and the gearbox. Moreover, a deflection limiter is provided, loosely attaching the flexible coupling to the gearbox to provide a predetermined axial range of motion, radial range of motion, and circumferential range of motion between the gearbox and the frame to which the flexible coupling is attached.