Abstract: A rotorcraft rotor blade assembly includes a stub spar extending less than a full span of the rotor blade assembly. An upper skin portion extends substantially the full span of the rotor blade assembly. A lower skin portion extends substantially the full span of the rotor blade assembly. The stub spar is positioned between the upper skin portion and the lower skin portion.

Abstract: An apparatus comprising a spinner fairing assembly comprising a spinner configured to be fixed relative to a gimbaled yoke coupled to a mast system, and a spinner base configured to be fixed relative to the mast system. A spinner fairing assembly comprising a spinner aligned along a first axis, and a spinner base aligned along a second axis and configured to interface with the spinner, wherein the spinner is configured to transition between a neutral position and a canted position with respect to the spinner base, wherein the first axis and the second axis are coincident in the neutral position, and wherein the first axis and the second axis are not coincident and meet at an origin within the spinner in the canted position.

Abstract: A tiltrotor aircraft includes a fuselage, a wing member extending from the fuselage, an engine disposed relative to the wing member and a proprotor mechanically coupled to the engine. The proprotor includes a plurality of proprotor blade assemblies each including a spar and a sheath extending spanwise along the spar forming the leading edge of the proprotor blade assembly. The spar has a root section, a main section and a tip section. The spar has a generally oval cross section at radial stations along the main section and a first edge having a structural bias relative to a generally oppositely disposed second edge at the radial stations along the main section.

Abstract: A rotorcraft rotor blade assembly includes a stub spar extending less than a full span of the rotor blade assembly. An upper skin portion extends substantially the full span of the rotor blade assembly. A lower skin portion extends substantially the full span of the rotor blade assembly. The stub spar is positioned between the upper skin portion and the lower skin portion.

Abstract: A rotorcraft rotor blade assembly includes a stub spar extending less than a full span of the rotor blade assembly. An upper skin portion extends substantially the full span of the rotor blade assembly. A lower skin portion extends substantially the full span of the rotor blade assembly. The stub spar is positioned between the upper skin portion and the lower skin portion.

Abstract: A rotor blade system includes a rotor blade having an outboard section and an inboard section, a hinge joint rigidly attached to the outboard section, and an adhedral tip engaged with the hinge joint. A method includes pivotally attaching an adhedral tip to the rotor blade and pivoting the adhedral tip during flight to change the flight performance characteristics of the blade during flight.

Abstract: A tiltrotor aircraft includes a fuselage, a wing member extending from the fuselage, an engine disposed relative to the wing member, a rotor hub assembly mechanically coupled to the engine and a plurality of proprotor blade assemblies rotatably mounted to the rotor hub assembly and operable for beamwise folding relative thereto. The proprotor blade assemblies each including a spar and a sheath extending spanwise along a leading edge of the spar. The spar has a root section, a main section and a tip section. The spar has a generally oval cross section at radial stations along the main section of the spar with the root section of the spar forming an integral tang assembly operable for coupling the spar to the rotor hub assembly.

Abstract: A rotor hub can include a yoke, a mast, and one or more radially oriented actuators. The first radial actuator and the second radial actuator each have a piston configured to impart a translation of the yoke relative to the mast. The radial actuators are configured to attenuate in-plane whirling vibrations. The rotor hub can also have actuators coupled between the mast and the yoke for attenuating flapping and vertical vibrations.

Abstract: According to one embodiment, a constant velocity (CV) joint includes a first yoke, a second yoke, and three bearings. The first yoke is configured to be rotatably coupled to an input device about a first axis and configured to receive the input device through a first opening. The second yoke is rotatably coupled to the first yoke about a second axis and rotatably coupled to an output device about a third axis. The first bearing is disposed about the first axis adjacent to the first yoke, the second bearing is disposed about the second axis adjacent to the first yoke or the second yoke, and the third bearing disposed about the third axis adjacent to the second yoke. The first and third bearings torsionally constrain movement the first yoke and the second yoke so as to achieve a substantially CV characteristic between the input device and the output device.

Abstract: A tiltrotor aircraft includes a fuselage, a wing member extending from the fuselage, an engine disposed relative to the wing member and a proprotor mechanically coupled to the engine. The proprotor includes a plurality of proprotor blade assemblies each including a spar and a sheath extending spanwise along the spar forming the leading edge of the proprotor blade assembly. The spar has a root section, a main section and a tip section. The spar has a generally oval cross section at radial stations along the main section and a first edge having a structural bias relative to a generally oppositely disposed second edge at the radial stations along the main section.

Abstract: A tiltrotor aircraft includes a fuselage, a wing member extending from the fuselage, an engine disposed relative to the wing member, a rotor hub assembly mechanically coupled to the engine and a plurality of proprotor blade assemblies rotatably mounted to the rotor hub assembly and operable for beamwise folding relative thereto. The proprotor blade assemblies each including a spar and a sheath extending spanwise along a leading edge of the spar. The spar has a root section, a main section and a tip section. The spar has a generally oval cross section at radial stations along the main section of the spar with the root section of the spar forming an integral tang assembly operable for coupling the spar to the rotor hub assembly.

Abstract: A drive link includes a first bearing housing, a second bearing housing, and a central portion coupled between the first bearing housing and the second bearing housing. The central portion includes a central radial bearing configured such that the central portion twists in response to cocking of the first bearing housing relative to the second bearing housing.

Abstract: A rotorcraft rotor blade assembly includes a stub spar extending less than a full span of the rotor blade assembly. An upper skin portion extends substantially the full span of the rotor blade assembly. A lower skin portion extends substantially the full span of the rotor blade assembly. The stub spar is positioned between the upper skin portion and the lower skin portion.

Abstract: One example of an actuation system for an active blade element of a rotor blade includes an actuator system coupled to a linear transmission system. The actuator system attaches to a structure within a rotor blade and provides a linear motion in a direction that is spanwise to the rotor blade. The linear transmission system is coupled with the actuator system and to an active blade element attached to the rotor blade. The linear transmission system receives the linear motion provided by the actuator system, and responsively provides at least a partial rotation of the active blade element about an axis of the linear transmission system which is in the direction that is substantially parallel to the spanwise axis of the rotor blade.

Abstract: A composite flexure that secures a rotor blade to a gimbaled yoke in a tiltrotor rotor system. The composite flexure includes a composite flexure member, a first end, and a second end. The first end of the composite flexure couples the composite flexure to the gimbaled yoke, and the second end of the composite flexure couples the composite flexure to the rotor blade. The composite flexure is twisted when the composite flexure is not subject to torsional loads in order to accommodate various forces imparted on the rotor system.

Abstract: According to one embodiment, a constant velocity (CV) joint includes a first yoke, a second yoke, and a control mechanism. The first yoke is configured to be rotatably coupled to an input device about a first axis and configured to receive the input device through a first opening. The second yoke is rotatably coupled to the first yoke about a second axis and rotatably coupled to an output device about a third axis. The control mechanism is adapted to constrain the first yoke and the second yoke so as to achieve a substantially CV characteristic between the input device and the output device.

Abstract: One example of a torque transfer system for a rotorcraft includes a first rotational joint connected to a rotorcraft rotary shaft. The first rotational joint receives a portion of a torque generated by rotation of the rotorcraft rotary shaft and transfers the portion of the torque to a rotorcraft rotating component. The torque transfer system also includes a second rotational joint of a different type connected to the rotorcraft rotary shaft. The second rotational joint receives a remainder of the torque generated by the rotation of the rotorcraft rotary shaft and transfers the remainder of the torque to the rotorcraft rotating component.

Abstract: A rotor blade system includes a rotor blade having an outboard section and an inboard section, a hinge joint rigidly attached to the outboard section, and an adhedral tip engaged with the hinge joint. A method includes pivotally attaching an adhedral tip to the rotor blade and pivoting the adhedral tip during flight to change the flight performance characteristics of the blade during flight.

Abstract: One example of a torque transfer system for a rotorcraft includes a first rotational joint connected to a rotorcraft rotary shaft. The first rotational joint receives a portion of a torque generated by rotation of the rotorcraft rotary shaft and transfers the portion of the torque to a rotorcraft rotating component. The torque transfer system also includes a second rotational joint of a different type connected to the rotorcraft rotary shaft. The second rotational joint receives a remainder of the torque generated by the rotation of the rotorcraft rotary shaft and transfers the remainder of the torque to the rotorcraft rotating component.

Abstract: A tiltrotor rotor hub comprises first and second configurations of yokes arranged in two parallel and axially offset planes, each having an equal number of two or more yokes substantially equally spaced about a mast, wherein a portion of each yoke overlaps with a portion of each azimuthally adjacent yoke. Another tiltrotor rotor hub is selectively positionable for operation in helicopter/airplane/transition modes and comprises substantially parallel and axially offset first and second planes, each containing a plurality of blade yokes arranged about a central axis and a portion of each yoke overlaps with a portion of each azimuthally adjacent yoke. Another tiltrotor rotor hub is coupled to a tiltrotor mast and comprises a stacked arrangement of blade yokes wherein a portion of each yoke overlaps with a portion of each azimuthally adjacent yoke, and a plurality of mounting components coupling each yoke to the overlapping azimuthally adjacent yoke.