Abstract: A drive system for a rotorcraft includes first and second gearbox assemblies and a lubrication assembly. The lubrication assembly includes first and second lubrication systems and a valve connected between the first and second lubrication systems such that when the valve is in a first position, a test mode of operation of the lubrication assembly is enabled and when the valve is in a second position, a normal mode of operation of the lubrication assembly is enabled. The lubrication assembly also includes a valve control unit operable to instruct the valve to selectively move between the first position and the second position.

Abstract: An exemplary tiltrotor aircraft with a hybrid drive system includes a first propulsion system having a first engine and a first supplemental driver operably coupled to a first proprotor that is operable between a helicopter mode and an airplane mode and a second propulsion system having a second engine and a second supplemental driver operably coupled to a second proprotor that is operable between a helicopter mode and an airplane mode.

Abstract: An exemplary tiltrotor aircraft with a hybrid drive system includes a first propulsion system having a first engine and a first supplemental driver operably coupled to a first proprotor that is operable between a helicopter mode and an airplane mode and a second propulsion system having a second engine and a second supplemental driver operably coupled to a second proprotor that is operable between a helicopter mode and an airplane mode.

Abstract: An exemplary tiltrotor aircraft with a hybrid drive system includes a first propulsion system having a first engine and a first supplemental driver operably coupled to a first proprotor that is operable between a helicopter mode and an airplane mode and a second propulsion system having a second engine and a second supplemental driver operably coupled to a second proprotor that is operable between a helicopter mode and an airplane mode.

Abstract: A mast lockout system for a tiltrotor aircraft having a proprotor assembly. The system includes a mast coupled to and rotatable with the proprotor assembly. A proprotor gearbox having a proprotor gearbox housing is configured to transmit torque and rotation energy to the mast. A lock assembly has first and second lock members. The first lock member is coupled to the mast between first and second mast bearings and configured to rotate with the mast. The second lock member is coupled to the proprotor gearbox housing. The lock assembly has a first position in which the first and second lock members are disengaged, thereby allowing rotation of the mast. The lock assembly has a second position in which the first and second lock members are engaged, thereby preventing rotation of the mast. The lock assembly is actuatable between the first and second positions.

Abstract: A selectable clutch assembly for a multimode powertrain of a rotorcraft. The selectable clutch assembly includes a freewheeling unit having input and output sides. The freewheeling unit has a driving mode wherein torque applied to the input side is transferred to the output side and an over running mode wherein torque applied to the output side is not transferred to the input side. A bypass assembly is coupled to and rotatable with the output side of the freewheeling unit and is actuatable between engaged and disengaged positions with the input side of the freewheeling unit. In the disengaged position, the freewheeling unit is operable in the driving and the over running modes such that the selectable clutch assembly is configured for unidirectional torque transfer. In the engaged position, the over running mode of the freewheeling unit is disabled such that the selectable clutch assembly is configured for bidirectional torque transfer.

Abstract: A locking mechanism for locking a driveshaft in cooperative engagement with an apparatus includes a drive portion coupled to the driveshaft and a driven portion coupled to the apparatus. The drive portion of the locking mechanism includes a housing with a first engagement portion, a ball cage with a plurality locking balls contained at least partially therein, and a chock biased away from the housing by a chock spring. The chock includes an outer wall configured to push the locking balls outward in a locked position and allow inward movement in an unlocked position. Movement of the chock, and therefore locking, is controlled by an actuator rod extending through a center of the locking mechanism. The driven portion includes a second engagement portion configured to cooperatively engage and receive torque from the first engagement portion, and a locking groove configured to receive a portion of each of the plurality of locking balls therein.

Abstract: A rotary propulsion system for a tiltrotor aircraft operable to transition between rotary and non rotary flight modes. The rotary propulsion system includes an engine coupled to a freewheeling unit. A gear system positioned between the freewheeling unit and a proprotor assembly has a torque path coupling assembly disposed between an engine side gear assembly and a rotor side gear assembly. In a disengaged position, the torque path coupling assembly interrupts the torque path between the engine and the proprotor assembly. In an engaged position, the torque path coupling assembly completes the torque path between the engine and the proprotor assembly. A hybrid power unit is configured to accelerate the engine side gear assembly to match the output rotating speed to the input rotating speed enabling the torque path coupling assembly to shift from the disengaged position to the engaged position.

Abstract: A selectable clutch assembly for a multimode powertrain of a rotorcraft. The selectable clutch assembly includes a freewheeling unit having input and output sides. The freewheeling unit has a driving mode wherein torque applied to the input side is transferred to the output side and an over running mode wherein torque applied to the output side is not transferred to the input side. A bypass assembly is coupled to and rotatable with the output side of the freewheeling unit and is actuatable between engaged and disengaged positions with the input side of the freewheeling unit. In the disengaged position, the freewheeling unit is operable in the driving and the over running modes such that the selectable clutch assembly is configured for unidirectional torque transfer. In the engaged position, the over running mode of the freewheeling unit is disabled such that the selectable clutch assembly is configured for bidirectional torque transfer.

Abstract: A rotary propulsion system for a tiltrotor aircraft operable to transition between rotary and non rotary flight modes. The rotary propulsion system includes an engine that is coupled to a freewheeling unit. A gear system has a torque path coupling assembly between a first gear assembly that is coupled to the freewheeling unit and a second gear assembly that is coupled to a proprotor assembly. The torque path coupling assembly has an engaged position wherein the output of the first gear assembly is coupled to the input of the second gear assembly thereby providing a torque path between the engine and the proprotor assembly. The torque path coupling assembly also has a disengaged position wherein the output of the first gear assembly is independent of the input of the second gear assembly thereby interrupting the torque path between the engine and the proprotor assembly.

Abstract: A locking mechanism for locking a driveshaft in cooperative engagement with an apparatus includes a drive portion coupled to the driveshaft and a driven portion coupled to the apparatus. The drive portion of the locking mechanism includes a housing with a first engagement portion, a ball cage with a plurality locking balls contained at least partially therein, and a chock biased away from the housing by a chock spring. The chock includes an outer wall configured to push the locking balls outward in a locked position and allow inward movement in an unlocked position. Movement of the chock, and therefore locking, is controlled by an actuator rod extending through a center of the locking mechanism. The driven portion includes a second engagement portion configured to cooperatively engage and receive torque from the first engagement portion, and a locking groove configured to receive a portion of each of the plurality of locking balls therein.

Abstract: An exemplary tiltrotor aircraft with a hybrid drive system includes a first propulsion system having a first engine and a first supplemental driver operably coupled to a first proprotor that is operable between a helicopter mode and an airplane mode and a second propulsion system having a second engine and a second supplemental driver operably coupled to a second proprotor that is operable between a helicopter mode and an airplane mode.

Abstract: A rotary propulsion system for a tiltrotor aircraft operable to transition between rotary and non rotary flight modes. The rotary propulsion system includes an engine that is coupled to a freewheeling unit. A gear system has a torque path coupling assembly between a first gear assembly that is coupled to the freewheeling unit and a second gear assembly that is coupled to a proprotor assembly. The torque path coupling assembly has an engaged position wherein the output of the first gear assembly is coupled to the input of the second gear assembly thereby providing a torque path between the engine and the proprotor assembly. The torque path coupling assembly also has a disengaged position wherein the output of the first gear assembly is independent of the input of the second gear assembly thereby interrupting the torque path between the engine and the proprotor assembly.

Abstract: A rotary propulsion system for a tiltrotor aircraft operable to transition between rotary and non rotary flight modes. The rotary propulsion system includes an engine coupled to a freewheeling unit. A gear system positioned between the freewheeling unit and a proprotor assembly has a torque path coupling assembly disposed between an engine side gear assembly and a rotor side gear assembly. In a disengaged position, the torque path coupling assembly interrupts the torque path between the engine and the proprotor assembly. In an engaged position, the torque path coupling assembly completes the torque path between the engine and the proprotor assembly. A hybrid power unit is configured to accelerate the engine side gear assembly to match the output rotating speed to the input rotating speed enabling the torque path coupling assembly to shift from the disengaged position to the engaged position.

Abstract: A mast lockout system for a tiltrotor aircraft having a proprotor assembly. The system includes a mast coupled to and rotatable with the proprotor assembly. A proprotor gearbox having a proprotor gearbox housing is configured to transmit torque and rotation energy to the mast. A lock assembly has first and second lock members. The first lock member is coupled to the mast between first and second mast bearings and configured to rotate with the mast. The second lock member is coupled to the proprotor gearbox housing. The lock assembly has a first position in which the first and second lock members are disengaged, thereby allowing rotation of the mast. The lock assembly has a second position in which the first and second lock members are engaged, thereby preventing rotation of the mast. The lock assembly is actuatable between the first and second positions.