Abstract: A lubricant system includes a first gearbox defining a first internal cavity, a second gearbox defining a second internal cavity, a first lubricant cooler positioned external the first and second internal cavities, a second lubricant cooler positioned external the first and second internal cavities, and a plurality of fluid passages fluidly connecting the first lubricant cooler and second lubricant coolers to each of the first gearbox and the second gearbox. The first lubricant cooler and the second lubricant cooler are configured to hold lubricant. The fluid passages include a first main fluid passage fluidly connecting the first lubricant cooler to the first gearbox, a second main fluid passage fluidly connecting the second lubricant cooler to the second gearbox, a first auxiliary passage fluidly connecting the first lubricant cooler to the second gearbox, and a second auxiliary passage fluidly connecting the second lubricant cooler to the first gearbox.

Abstract: A gearbox oil cooling assembly for a gearbox driving a drive shaft having a drive shaft coupling. The assembly includes a heat exchanger to receive and cool an oil from the gearbox and having an inlet. Also included is an impeller axially disposed between the heat exchanger and the drive shaft coupling, wherein the impeller is operatively coupled to, and rotated by, the drive shaft operatively coupled to the drive shaft coupling. Further included is an exhaust duct operatively coupled to the heat exchanger and disposed radially outwardly around the impeller and defining an airflow pathway through which air passes through the inlet, the impeller and through the exhaust duct according to the rotation of the impeller to cool the oil in the heat exchanger.

Abstract: A propeller system includes a propeller located at a tail section and a drive shaft operably connected to the propeller to drive the propeller about a propeller axis. A propeller gearbox connects the propeller to the drive shaft and a propeller gearbox lubricant cooler is operably connected to the propeller gearbox and disposed circumferentially about the drive shaft. The propeller gearbox lubricant cooler transfers thermal energy from a flow of lubricant flowing therethrough to a flow of air flowing through the tail section across the propeller gearbox lubricant cooler. A method of cooling a gearbox for a propeller includes circulating a volume of lubricant through a propeller gearbox and flowing the lubricant into a propeller gearbox cooler. Thermal energy is transferred from the lubricant to a flow of air flowing across the propeller gearbox cooler and the flow of air is vented from the tail section of the rotorcraft.

Abstract: A multi-plate clutch apparatus is provided and includes a multi-plate clutch disposed to occupy clutch and non-clutch positions at which rotation of an input shaft is and is not transmitted to an output shaft, respectively, a drive element disposed about the multi-plate clutch and configured to generate rotational energy and a linear actuator disposed to convert the rotational energy of the drive element to linear movement by which the multi-plate clutch is controllable to occupy one of the clutch and non-clutch positions.

Abstract: A gearbox oil cooling assembly for a gearbox driving a drive shaft having a drive shaft coupling. The assembly includes a heat exchanger to receive and cool an oil from the gearbox and having an inlet. Also included is an impeller axially disposed between the heat exchanger and the drive shaft coupling, wherein the impeller is operatively coupled to, and rotated by, the drive shaft operatively coupled to the drive shaft coupling. Further included is an exhaust duct operatively coupled to the heat exchanger and disposed radially outwardly around the impeller and defining an airflow pathway through which air passes through the inlet, the impeller and through the exhaust duct according to the rotation of the impeller to cool the oil in the heat exchanger.

Abstract: An impeller retention apparatus is provided. The impeller retention apparatus includes a bearing element, a rotatable gear shaft rotatably supported within an outer body by the bearing element, an impeller disposed about and coupled to the rotatable gear shaft to rotate with the rotatable gear shaft, a preload spacer and a flexible coupling. The preload spacer is disposed along the rotatable gear shaft between the impeller and the bearing element and includes a forward preload spacer end abutting an aft end of the bearing element, an aft preload spacer end abutting a forward face of the impeller and an elastic element that biases the impeller away from the bearing element in an axial direction along the rotatable gear shaft. The flexible coupling is coupled to the rotatable gear shaft such that the outer body and the flexible coupling cooperatively define an annulus from which the impeller receives an airflow.

Abstract: A propeller system includes a propeller located at a tail section and a drive shaft operably connected to the propeller to drive the propeller about a propeller axis. A propeller gearbox connects the propeller to the drive shaft and a propeller gearbox lubricant cooler is operably connected to the propeller gearbox and disposed circumferentially about the drive shaft. The propeller gearbox lubricant cooler transfers thermal energy from a flow of lubricant flowing therethrough to a flow of air flowing through the tail section across the propeller gearbox lubricant cooler. A method of cooling a gearbox for a propeller includes circulating a volume of lubricant through a propeller gearbox and flowing the lubricant into a propeller gearbox cooler. Thermal energy is transferred from the lubricant to a flow of air flowing across the propeller gearbox cooler and the flow of air is vented from the tail section of the rotorcraft.

Abstract: A propulsor gearbox assembly for a translational thrust propeller includes a housing defining an interior cavity, a planetary gear assembly contained within the interior cavity, an input shaft aligned on a first axis or rotation, and an output shaft aligned along a second axis of rotation. The first axis of rotation is coaxial with the second axis of rotation.

Abstract: A multi-plate clutch apparatus is provided and includes a multi-plate clutch disposed to occupy clutch and non-clutch positions at which rotation of an input shaft is and is not transmitted to an output shaft, respectively, a drive element disposed about the multi-plate clutch and configured to generate rotational energy and a linear actuator disposed to convert the rotational energy of the drive element to linear movement by which the multi-plate clutch is controllable to occupy one of the clutch and non-clutch positions.

Abstract: An impeller retention apparatus is provided and includes a bearing element, a rotatable shaft, which is rotatably supported within an outer body by the bearing element, an impeller disposed about and coupled to the shaft to rotate with the shaft and a preload spacer disposed along the shaft between the impeller and the bearing element, the preload spacer comprising an elastic element which biases the impeller away from the bearing element in an axial direction along the shaft.

Abstract: An exemplary lock out assembly includes a lock nut defined about an axis. The lock nut defines inner apertures along an inner diameter and outer apertures along an outer diameter. The inner apertures are at least partially threaded. The outer apertures are at least partially threaded. The inner apertures are radially spaced from the outer apertures.

Abstract: A drive system for a high speed rotary-wing aircraft includes a combiner gearbox in meshing engagement with a main gearbox. The combiner gearbox is driven by one or more engines such that a main rotor system and a translational thrust system are driven thereby. The engine drives the combiner gearbox and thus the main gearbox through an overrunning clutch. The drive system permits the main rotor system RPM to be controlled by offloading power to the translational thrust system during a high speed flight profile.

Abstract: A locknut which defines a multiple of inner apertures about an inner diameter and a multiple of outer apertures about an outer diameter.

Abstract: A spring clutch has a housing containing first and second sleeves surrounding first and second longitudinal spans of a coil spring. A carrier mounting at least one of the sleeves relative to the housing flexes to maintain alignment of axes of the sleeves to control forces on the portion of the spring spanning the gap between the sleeves.