Abstract: A turboshaft engine transmission with a torque measurement system is provided. The turboshaft engine transmission includes a front housing, a rear housing, a mating flange axially interposed between the front and rear housings, the mating flange defining a sensing bolt hole, assembly bolts disposed to assemble the front and rear housings to the mating flange with a preload sufficient to maintain assembly during engine operational conditions and a sensing bolt installed in the sensing bolt hole to measure forces exerted on the mating flange by the front and rear housings.

Abstract: An aircraft motor assembly is provided and includes a high-power gear, a rear housing from which the high-power gear is exposed, a gear train, which is disposable in multiple orientations relative to the high-power gear, and which includes a first end configured to register with the high-power gear with the gear train disposed in one of the multiple orientations and a second end and a front housing configured to be installed about the high-power gear and the first end of the gear train and to accommodate the second end protruding outwardly from the front housing in a direction that corresponds to the one of the multiple orientations in which the gear train is disposed.

Abstract: A reduction gearbox of an aircraft propulsion system includes an input shaft configured to input rotational energy into the reduction gearbox, an output shaft configured to output rotational energy from the reduction gearbox to a propulsor of the aircraft propulsion system, and an epicyclic gear arrangement mechanically coupling the output shaft to the input shaft. A transfer gear is positioned at a component of the epicyclic gear arrangement and is configured to mechanically couple an accessory component to the reduction gearbox.

Abstract: The hybrid aircraft power plant can have a load, a thermal engine coupled to drive the load via a clutch, and coupled to drive a first lubricant pump, an electric motor coupled to drive the load and a second lubricant pump. In a first mode, the clutch is in an engaged configuration, and the thermal engine drives the load via the clutch and drives the first lubricant pump. In a second mode, in which the clutch is in the disengaged configuration and in which the thermal engine may be inoperative, the electric motor is operated to drive the load and the second lubricant pump.

Abstract: A reduction gearbox of an aircraft propulsion system includes an input shaft configured to input rotational energy into the reduction gearbox, an output shaft configured to output rotational energy from the reduction gearbox to a propulsor of the aircraft propulsion system, and an epicyclic gear arrangement mechanically coupling the output shaft to the input shaft. A transfer gear is positioned at a component of the epicyclic gear arrangement and is configured to mechanically couple an accessory component to the reduction gearbox.

Abstract: The power plant can have a structure; an output shaft connectable to a load, the output shaft rotatable about an axis relative the structure; a thermal engine secured to the structure, the thermal engine having a thermal engine shaft; an electric motor having a stator and a rotor shaft, the stator secured to the structure; an epicyclic gearing having a sun gear coaxial to a ring gear, a plurality of planet gears meshed between the sun gear and the ring gear, and a carrier coaxial to the sun gear and to the ring gear, the sun gear, carrier, and ring gear being rotatable relative the casing structure, the output shaft and the rotor shaft both coupled to the carrier, and the thermal engine shaft coupled to sun gear and the carrier; and an overrunning clutch operable to prevent the rotation of the ring gear in one angular direction.

Abstract: An aircraft motor assembly is provided and includes a high-power gear, a rear housing from which the high-power gear is exposed, a gear train, which is disposable in multiple orientations relative to the high-power gear, and which includes a first end configured to register with the high-power gear with the gear train disposed in one of the multiple orientations and a second end and a front housing configured to be installed about the high-power gear and the first end of the gear train and to accommodate the second end protruding outwardly from the front housing in a direction that corresponds to the one of the multiple orientations in which the gear train is disposed.

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.