Abstract: An aircraft includes a frame, a transmission, and a liquid inertia vibration elimination (“LIVE”) system coupled between the frame and the transmission. The LIVE system is configured to attenuate communication of vibrations from the transmission to the frame. The LIVE system includes a first liquid zone, a second liquid zone, a plug at least partially segregating the first liquid zone from the second liquid zone, and the plug has an aperture in fluid communication with the first liquid zone and the second liquid zone. A splash guard is disposed within the second liquid zone and offset from the plug.

Abstract: A vibration attenuator has a first spinner configured for rotation about a first axis and a first mass coupled to the first spinner for rotation therewith, the first mass being movable radially relative to the first axis between an inner position and an outer position. An actuator is coupled to the first mass for selectively controlling a radial location of the first mass relative to the axis, and a first motor is configured for driving the first spinner in rotation about the first axis.

Abstract: One embodiment described herein is a damper for a rotor system, the damper comprising a cylindrical housing having a hollow interior; a piston disposed within the hollow interior and extending along a central axis of the housing; a first attachment member disposed on a first end of the damper and connected to the housing; a second attachment member disposed on a second end of the damper and connected to the piston; and a conductive cover wrapped around a portion of an exterior surface of the housing between the first attachment member and the second attachment member.

Abstract: One embodiment is a rotor system including a rotor hub comprising a plurality of extension arms for connecting rotor blades to the rotor hub; a plurality of dampers connected between a respective one of the extension arms and the rotor hub; and a fairing disposed over the rotor hub, the fairing including an inlet plenum through which air is drawn from outside the fairing into the fairing; and at least one duct for conducting the air toward the at least one of the dampers.

Abstract: A vibration attenuation system as shown and described.

Abstract: A vibration attenuation system for attenuating vibrations in a mast of an aircraft includes a weight attached to the mast but free to orbit about the mast. The weight can be comprised of one or more weight assemblies. Embodiments can include a single weight, or plural weight assemblies wherein each weight assembly can include a mechanical interconnecting mechanism so that each weight assembly receives feedback regarding the position and movement of one or more other weight assemblies. Each weight can be associated with a spring that urges the weight towards a neutral position. Rotation of the mast can cause the weight to orbit about the mast and self-excite such that the weight acts against the urging of the spring towards an attenuating position.

Abstract: One embodiment described herein is a damper for a rotor system, the damper comprising a cylindrical housing having a hollow interior; a piston disposed within the hollow interior and extending along a central axis of the housing; a first attachment member disposed on a first end of the damper and connected to the housing; a second attachment member disposed on a second end of the damper and connected to the piston; and a conductive cover wrapped around a portion of an exterior surface of the housing between the first attachment member and the second attachment member.

Abstract: One embodiment is a rotor system including a rotor hub comprising a plurality of extension arms for connecting rotor blades to the rotor hub; a plurality of dampers connected between a respective one of the extension arms and the rotor hub; and a fairing disposed over the rotor hub, the fairing including an inlet plenum through which air is drawn from outside the fairing into the fairing; and at least one duct for conducting the air toward the at least one of the dampers.

Abstract: A vibration attenuation system for attenuating vibrations in a mast of an aircraft includes a weight attached to the mast but free to orbit about the mast. The weight can be comprised of one or more weight assemblies. Embodiments can include a single weight, or plural weight assemblies wherein each weight assembly can include a mechanical interconnecting mechanism so that each weight assembly receives feedback regarding the position and movement of one or more other weight assemblies. Each weight can be associated with a spring that urges the weight towards a neutral position. Rotation of the mast can cause the weight to orbit about the mast and self-excite such that the weight acts against the urging of the spring towards an attenuating position.

Abstract: The present invention includes methods of preparing a composite structure comprising: placing a first ply of a fibrous material with a curable material on a layup tool; adding one or more additional plies on the first ply, wherein each of the one or more additional plies has a perimeter that is different in size around the perimeter than a previous ply to form a taper; and curing the composite structure, wherein the curable material is selected to minimize, limit, control, or eliminate the outflow of the curable material along the perimeter of the composite structure during the curing step.

Abstract: A vibration attenuation system for attenuating vibrations in a mast of an aircraft includes a weight attached to the mast but free to orbit about the mast. The weight can be comprised of one or more weight assemblies. Embodiments can include a single weight, or plural weight assemblies wherein each weight assembly can include a mechanical interconnecting mechanism so that each weight assembly receives feedback regarding the position and movement of one or more other weight assemblies. Each weight can be associated with a spring that urges the weight towards a neutral position. Rotation of the mast can cause the weight to orbit about the mast and self-excite such that the weight acts against the urging of the spring towards an attenuating position.

Abstract: A vibration attenuation system for attenuating vibrations in a mast of an aircraft includes a weight attached to the mast but free to orbit about the mast. The weight can be comprised of one or more weight assemblies. Embodiments can include a single weight, or plural weight assemblies wherein each weight assembly can include a mechanical interconnecting mechanism so that each weight assembly receives feedback regarding the position and movement of one or more other weight assemblies. Each weight can be associated with a spring that urges the weight towards a neutral position. Rotation of the mast can cause the weight to orbit about the mast and self-excite such that the weight acts against the urging of the spring towards an attenuating position.

Abstract: A vibration attenuation system for attenuating vibrations in a mast of an aircraft includes a weight attached to the mast but free to orbit about the mast. The weight can be comprised of one or more weight assemblies. Embodiments can include a single weight, or plural weight assemblies wherein each weight assembly can include a mechanical interconnecting mechanism so that each weight assembly receives feedback regarding the position and movement of one or more other weight assemblies. Each weight can be associated with a spring that urges the weight towards a neutral position. Rotation of the mast can cause the weight to orbit about the mast and self-excite such that the weight acts against the urging of the spring towards an attenuating position.

Abstract: A bearing assembly for coupling a proprotor blade to a yoke in a proprotor system. The bearing assembly is positionable within an inboard pocket of a blade arm of the yoke. The proprotor system is operable for use on a tiltrotor aircraft having helicopter and airplane flight modes. The bearing assembly includes a centrifugal force bearing and a shear bearing having an inboard beam coupled therebetween. The centrifugal force bearing has a mating surface, a lateral movement constraint feature and at least one radially extending anti-rotation feature. The inboard beam has a mating surface in a contact relationship with the mating surface of the centrifugal force bearing, a lateral movement constraint feature operably associated with the lateral movement constraint feature of the centrifugal force bearing and at least one radially extending anti-rotation feature that corresponds with the at least one radially extending anti-rotation feature of the centrifugal force bearing.

Abstract: A proprotor system for a tiltrotor aircraft includes a yoke having a plurality of blade arms each having an inboard pocket. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets. Each of a plurality of inboard beams is disposed at least partially between a centrifugal force bearing and a shear bearing of each bearing assembly and has a proprotor blade coupled thereto. Each of a plurality of latch assemblies selectively couples one of the bearing assemblies to the yoke. Each latch assembly is rotatable relative to the yoke between an engaged position wherein the latch assembly is engagable with one of the bearing assemblies to couple the bearing assembly to the yoke and a disengaged position wherein the latch assembly is disengaged from the respective bearing assembly enabling installation and removal of the respective bearing assembly relative to the respective pocket.

Abstract: A proprotor system for a tiltrotor aircraft having helicopter and airplane flight modes includes a yoke having a plurality of blade arms each having an inboard pocket. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets with each bearing assembly including a bearing cage, a shear bearing and a centrifugal force bearing. Each of a plurality of inboard beams is disposed at least partially between one of the centrifugal force bearings and one of the shear bearings. Each of a plurality of proprotor blades is coupled to one of the inboard beams. Hub bolts couple each of the bearing cages to the yoke such that the hub bolts provide centrifugal force load paths between the bearing assemblies and the yoke inboard of the inboard pockets.

Abstract: A proprotor system for a tiltrotor aircraft having a helicopter flight mode and an airplane flight mode includes a yoke having a plurality of blade arms each having an inboard pocket with a load transfer surface. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets. Each of a plurality of inboard beams is disposed at least partially between a centrifugal force bearing and a shear bearing of each bearing assembly and has a proprotor blade coupled thereto. Each of a plurality of independent shoes is coupled between one of the centrifugal force bearings and the yoke. Each shoe has a load transfer surface that has a contact relationship with the load transfer surface of the respective inboard pocket forming a centrifugal force load path therebetween.

Abstract: A proprotor system for a tiltrotor aircraft having helicopter and airplane flight modes includes a yoke having a plurality of blade arms each having an inboard pocket with an outboard surface. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets with each bearing assembly including a shear bearing and a centrifugal force bearing having an integral shoe with an outboard surface. Each of a plurality of inboard beams is disposed at least partially between one of the centrifugal force bearings and one of the shear bearings. Each of a plurality of proprotor blades is coupled to one of the inboard beams. The integral shoes are coupled to the yoke such that there is a spaced apart relationship between the outboard surfaces of the integral shoes and the outboard surfaces of the pockets to prevent centrifugal force load transfer therebetween.

Abstract: A proprotor system for a tiltrotor aircraft includes a yoke having a plurality of blade arms each having an inboard pocket. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets. Each of a plurality of inboard beams is disposed at least partially between a centrifugal force bearing and a shear bearing of each bearing assembly and has a proprotor blade coupled thereto. Each of a plurality of latch assemblies selectively couples one of the bearing assemblies to the yoke. Each latch assembly is rotatable relative to the yoke between an engaged position wherein the latch assembly is engagable with one of the bearing assemblies to couple the bearing assembly to the yoke and a disengaged position wherein the latch assembly is disengaged from the respective bearing assembly enabling installation and removal of the respective bearing assembly relative to the respective pocket.

Abstract: A proprotor system for a tiltrotor aircraft having helicopter and airplane flight modes includes a yoke having a plurality of blade arms each having an inboard pocket. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets with each bearing assembly including a bearing cage, a shear bearing and a centrifugal force bearing. Each of a plurality of inboard beams is disposed at least partially between one of the centrifugal force bearings and one of the shear bearings. Each of a plurality of proprotor blades is coupled to one of the inboard beams. Hub bolts couple each of the bearing cages to the yoke such that the hub bolts provide centrifugal force load paths between the bearing assemblies and the yoke inboard of the inboard pockets.