Abstract: In one aspect, this application describes a blade retention system—for a variable pitch aircraft proprotor system—comprising a double conical blade root encapsulated by a split sleeve. Some embodiments described additionally include fail-operational features. The preload of the blade pitch bearings pushes the metallic split sleeve into the bond line with the blade root.

Abstract: In a first aspect, described herein is a direct drive electric aircraft propulsion wherein the propulsion rotor torque is decoupled from the primary proprotor mast moment forces. A hub shaft locates the propulsion proprotor assembly in space relative to the aircraft nacelle, while a motor torque coupler transfers torque from the electric motor to the propulsion rotor while resolving a negligible amount of mast moment through the electric motor.

Abstract: In an embodiment, proprotor pitch ranges used during nominal cruise flight may be varied. By selecting ideal combinations of proprotor pitch angle and proprotor rpm, instead of the proprotor blade pitch bearing spending most of its time in a first range, multiple ranges may be alternated between. Additionally, in an aircraft with multiple proprotors, the portion of total thrust produced by each individual proprotor may be varied over time in order to allow for proprotor blade pitch angle to be varied without varying proprotor rpm. By properly cycling between different blade pitch ranges, bearing life can be significantly increased.

Abstract: A rotor blade retention assembly is configured to connect a rotor blade to a central hub comprising a hub arm coupled to and extending radially outward from a hub bowl. The hub arm includes a hub arm lug. The rotor blade retention assembly includes a tension-torsion strap with an inboard end and an outboard end, the inboard end including an inboard pin hole and the outboard end including an outboard pin hole. The rotor blade retention assembly further includes an inboard blade pin and an outboard blade pin. The inboard blade pin is configured to extend through the hub arm lug and the inboard pin hole and to couple the inboard end of the tension-torsion strap to the hub arm. The outboard blade pin is configured to extend through a blade lug of a rotor blade and the outboard pin hole and to couple the outboard end of the tension-torsion strap to the rotor blade.

Abstract: A spherical bearing which extends from and connects to a deformable component includes an outer member and an inner member. The inner member is pivotable relative to the outer member about an axis. The inner member has an opening formed therein that defines a plurality of coplanar contact surfaces shaped to accommodate and contact the component. The plurality of contact surfaces are movable to accommodate deformation of the component positioned within the opening.

Abstract: An aircraft is provided and includes a non-rotating frame, an engine disposed in the non-rotating frame, a rotating frame, which is drivable by the engine to rotate relative to the non-rotating frame to generate lift and thrust, the rotating frame including a hub and rotor blades extending outwardly from the hub, an actuation system including electro-mechanical actuators (EMAs) respectively disposed in the rotating frame between the hub and the rotor blades, each EMA including a rotary inductive device, a gear train associated with each EMA and the corresponding rotary inductive device to convert linear displacements of a piston responsive to rotor blade lead/lag into rotation of the rotary inductive device and a controller that controls the rotary inductive device to operate, in a first mode, as a motor which drives the gear train, and, in a second mode, as a generator which is driven by the gear train.

Abstract: A blade damper with a magnetic contaminants trap includes, a housing defining a cavity, a piston in operable communication with the housing dividing the cavity into at least a first chamber and a second chamber, a passageway in operable communication with the cavity configured to allow fluid within the cavity to move between the first chamber and the second chamber through the passageway, and at least one magnet in operable communication with fluid in at least one of the cavity and the passageway, such that magnetic contaminants are prevented from freely moving about within the fluid after having been attracted toward the at least one magnet by a magnetic field of the at least one magnet.

Abstract: A swashplate guide for use with a spherical bearing and which connects with an adjacent component includes a hollow cylindrical tube formed from a composite material. An exterior surface of the hollow cylindrical tube provides an engagement surface with the spherical bearing. A flange arranged at an end of the hollow cylindrical tube provides an interface with the adjacent component.

Abstract: A spherical bearing which extends from and connects to a deformable component includes an outer member and an inner member. The inner member is pivotable relative to the outer member about an axis. The inner member has an opening formed therein that defines a plurality of coplanar contact surfaces shaped to accommodate and contact the component. The plurality of contact surfaces are movable to accommodate deformation of the component positioned within the opening.

Abstract: A bearing sleeve assembly includes a rigid inner element having a cylindrical inner diameter bore and an outer surface that is non-cylindrical. Also included is a rigid outer element spaced radially outwardly from the rigid inner element, the rigid outer element comprising a cylindrical member with a uniform cross-section that forms a ring with an inner-diameter surface and an outer-diameter surface, the outer element's inner-diameter surface and the non-cylindrical outer surface of the inner element defining a non-uniform annulus therebetween. Further included is an elastomeric core disposed between the rigid inner element and the rigid outer element within the non-uniform annulus, the elastomeric core having a first thickness at a first location and a second thickness at a second location, the first thickness being greater than the second thickness.

Abstract: A blade damper with a magnetic contaminants trap includes, a housing defining a cavity, a piston in operable communication with the housing dividing the cavity into at least a first chamber and a second chamber, a passageway in operable communication with the cavity configured to allow fluid within the cavity to move between the first chamber and the second chamber through the passageway, and at least one magnet in operable communication with fluid in at least one of the cavity and the passageway, such that magnetic contaminants are prevented from freely moving about within the fluid after having been attracted toward the at least one magnet by a magnetic field of the at least one magnet.

Abstract: A swashplate guide for use with a spherical bearing and which connects with an adjacent component includes a hollow cylindrical tube formed from a composite material. An exterior surface of the hollow cylindrical tube provides an engagement surface with the spherical bearing. A flange arranged at an end of the hollow cylindrical tube provides an interface with the adjacent component.

Abstract: An aircraft is provided and includes a non-rotating frame, an engine disposed in the non-rotating frame, a rotating frame, which is drivable by the engine to rotate relative to the non-rotating frame to generate lift and thrust, the rotating frame including a hub and rotor blades extending outwardly from the hub, an actuation system including electro-mechanical actuators (EMAs) respectively disposed in the rotating frame between the hub and the rotor blades, each EMA including a rotary inductive device, a gear train associated with each EMA and the corresponding rotary inductive device to convert linear displacements of a piston responsive to rotor blade lead/lag into rotation of the rotary inductive device and a controller that controls the rotary inductive device to operate, in a first mode, as a motor which drives the gear train, and, in a second mode, as a generator which is driven by the gear train.

Abstract: A bearing sleeve assembly includes a rigid inner element having a cylindrical inner diameter bore and an outer surface that is non-cylindrical. Also included is a rigid outer element spaced radially outwardly from the rigid inner element, the rigid outer element comprising a cylindrical member with a uniform cross-section that forms a ring with an inner-diameter surface and an outer-diameter surface, the outer element's inner-diameter surface and the non-cylindrical outer surface of the inner element defining a non-uniform annulus therebetween. Further included is an elastomeric core disposed between the rigid inner element and the rigid outer element within the non-uniform annulus, the elastomeric core having a first thickness at a first location and a second thickness at a second location, the first thickness being greater than the second thickness.