Abstract: A spline coupling comprises a male spline member having male spline teeth and a female spline member having female spline teeth complementary to and engaged with the male spline teeth. One or more of the female spline teeth has a tooth height lesser than a tooth height of another one or more of the female spline teeth. The tooth height of the one or more of the female spline teeth is defined by a top land surface of the one or more of the female spline teeth. The tooth height of the other one or more of the female spline teeth is defined by a top land surface of the other one or more of the female spline teeth. A drainage hole in the top land surface of the one or more of the female spline teeth passes through the one or more of the female spline teeth.

Abstract: An engine comprises a first power input and a second power input, a main load, and a transmission engaged with the first power input, the second power input, and the main load. An epicyclic gear train is engaged with the first power input and the main load. A brake in a drive condition engages with the epicyclic gear train to transfer power from the first power input to the main load. The brake in a start condition disengages from the epicyclic gear train to decouple the first power input from the main load. A start assist motor is engaged with part of the transmission separate from the epicyclic gear train. The start assist motor in the start condition rotates the main load to initiate start up of the engine, and in the drive condition prevents transferring power to the main load.

Abstract: A spline coupling comprises a male spline member having male spline teeth and a female spline member having female spline teeth complementary to and engaged with the male spline teeth. One or more of the female spline teeth has a tooth height lesser than a tooth height of another one or more of the female spline teeth. The tooth height of the one or more of the female spline teeth is defined by a top land surface of the one or more of the female spline teeth. The tooth height of the other one or more of the female spline teeth is defined by a top land surface of the other one or more of the female spline teeth. A drainage hole in the top land surface of the one or more of the female spline teeth passes through the one or more of the female spline teeth.

Abstract: A valve has a housing having an inlet and an outlet. A valve element is biased towards a closed position in which the valve element restricts fluid flow from the inlet to the outlet. The valve element is axially movable by fluid pressure at the inlet towards an open position in which the inlet is in fluid flow communication with the outlet. The valve further has a damping chamber having a metering orifice in fluid communication with the inlet. The damping chamber has an axially facing surface defined by the valve element and having a variable volume varying from a minimum volume when the valve element is in its closed position to a maximum volume when the valve element is in its open position.

Abstract: An engine comprises a first power input and a second power input, a main load, and a transmission engaged with the first power input, the second power input, and the main load. An epicyclic gear train is engaged with the first power input and the main load. A brake in a drive condition engages with the epicyclic gear train to transfer power from the first power input to the main load. The brake in a start condition disengages from the epicyclic gear train to decouple the first power input from the main load. A start assist motor is engaged with part of the transmission separate from the epicyclic gear train. The start assist motor in the start condition rotates the main load to initiate start up of the engine, and in the drive condition prevents transferring power to the main load.

Abstract: An engine includes first and second power inputs, and a power output. A transmission includes an epicyclic gear train engaged with the first power input and selectively engageable with the power output. The gear train has a sun gear centrally disposed and defining a center axis of the gear train, a ring gear, and planet gears mounted to a carrier. The planet gears are rotatable about respective planet gear axes. The planet gears are disposed in meshed engagement with the sun gear and the ring gear. A brake engageable in a first position with one of the sun gear, the carrier, and the ring gear slows a rotation thereof to transfer power from the first power input to the power output. The brake in a second position is disengageable from the sun gear, the carrier or the ring gear to decouple the first power input from the power output.

Abstract: An engine includes a first power source configured to drive a first power input, a power output, and a transmission engaged with the first power input and the power output. The transmission includes an epicyclic gear train engaged with the first power input and selectively engageable with the power output. A brake is engageable in a drive condition with the epicyclic gear train to transfer power from the first power input to the power output. The brake in a start condition is disengageable to decouple the first power input from the power output. A start assist motor associated with a second power source is engaged with the transmission to rotate the power output.

Abstract: An engine includes a first power source configured to drive a first power input, a power output, and a transmission engaged with the first power input and the power output. The transmission includes an epicyclic gear train engaged with the first power input and selectively engageable with the power output. A brake is engageable in a drive condition with the epicyclic gear train to transfer power from the first power input to the power output. The brake in a start condition is disengageable to decouple the first power input from the power output. A start assist motor associated with a second power source is engaged with the transmission to rotate the power output.

Abstract: An engine includes first and second power inputs, and a power output. A transmission includes an epicyclic gear train engaged with the first power input and selectively engageable with the power output. The gear train has a sun gear centrally disposed and defining a center axis of the gear train, a ring gear, and planet gears mounted to a carrier. The planet gears are rotatable about respective planet gear axes. The planet gears are disposed in meshed engagement with the sun gear and the ring gear. A brake engageable in a first position with one of the sun gear, the carrier, and the ring gear slows a rotation thereof to transfer power from the first power input to the power output. The brake in a second position is disengageable from the sun gear, the carrier or the ring gear to decouple the first power input from the power output.

Abstract: A valve has a housing having an inlet and an outlet. A valve element is biased towards a closed position in which the valve element restricts fluid flow from the inlet to the outlet. The valve element is axially movable by fluid pressure at the inlet towards an open position in which the inlet is in fluid flow communication with the outlet. The valve further has a damping chamber having a metering orifice in fluid communication with the inlet. The damping chamber has an axially facing surface defined by the valve element and having a variable volume varying from a minimum volume when the valve element is in its closed position to a maximum volume when the valve element is in its open position.

Abstract: A gas turbine engine comprises bearing(s). A structure supporting the bearing defines a bearing cavity surrounding the at least one bearing, an ambient chamber and an intermediate chamber having a portion between the bearing cavity and the ambient chamber, with at least one wall forming a passage from the bearing cavity to the ambient chamber and through the portion of the intermediate chamber. A tube is received in the passage and having a first end open to the bearing cavity and a second end open to the ambient chamber, the second end adapted to be connected to a conduit for fluid communication between the bearing cavity and the through the tube, wherein a portion of or near the first end of the tube is sealingly joined to the at least one wall, and the second end of the tube contacts the at least one wall and is free to move relative to the at least one wall.

Abstract: A reduction gear box is part of a gas turbine engine and includes a casing and reduction epicyclic gear stages within the casing. The reduction gear stages comprising at least an epicyclic array of gears meshing together with at least one planetary gear mounted for rotation on a gear carrier and a bearing associated therewith. A lubricating oil delivery system is provided within the casing, surrounding a portion of the gear carrier. The oil delivery system includes a conduit; a closed oil reservoir; a first metered opening communicating the conduit with the reservoir and a plurality of metered outlet openings communicating the reservoir with the gear carrier and the bearing such that the reservoir is filled with oil in normal flight operating conditions and the oil trapped in the reservoir is released to the carrier and bearing when a temporary drop in the oil system pressure occurs.

Abstract: A reduction gear box is part of a gas turbine engine and includes a casing and reduction epicyclic gear stages within the casing. The reduction gear stages comprising at least an epicyclic array of gears meshing together with at least one planetary gear mounted for rotation on a gear carrier and a bearing associated therewith. A lubricating oil delivery system is provided within the casing, surrounding a portion of the gear carrier. The oil delivery system includes a conduit; a closed oil reservoir; a first metered opening communicating the conduit with the reservoir and a plurality of metered outlet openings communicating the reservoir with the gear carrier and the bearing such that the reservoir is filled with oil in normal flight operating conditions and the oil trapped in the reservoir is released to the carrier and bearing when a temporary drop in the oil system pressure occurs.