Abstract: A rotor yoke manufactured by a process comprising preparing a molded rotor yoke in a closed cavity tool and possibly machining at least one portion of the molded rotor yoke to form the rotor yoke. In the preferred embodiment, the preparing of the molded rotor yoke is accomplished by applying layers of uncured low-flow composite material and a layer of uncured high-flow adhesive; substantially enclosing the uncured molded rotor yoke in the closed cavity tool; and applying pressure so as to compress the uncured molded rotor yoke; and curing the uncured molded rotor yoke. During the curing process, the high-flow adhesive bleeds out of the molded rotor yoke, thereby preventing marcels from forming through movement of the low-flow composite material.

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 system and method to tilt coaxial counter-rotating rotor hub assemblies relative to a fuselage. The system includes a first rotor hub assembly and a second rotor hub assembly spaced apart from the first hub assembly and carried by the fuselage. The method includes pivotally attaching the first rotor hub assembly and the second rotor hub assembly to a pivot joint and thereafter tilting the first rotor hub assembly and the second rotor hub assembly about the pivot joint with a driver.

Abstract: The system and method of the present application relate to a lead/lag damper for a rotorcraft. The lead/lag damper is configured to harvest power from the lead/lag oscillatory motions of rotor blades with an electromagnetic linear motor/generator. Further, the lead/lag damper is configured to treat the lead/lag motions with the electromagnetic linear motor/generator. The system and method is well suited for use in the field of aircraft, in particular, helicopters and other rotary wing aircraft.

Abstract: According to one embodiment, a rotor head includes a yoke, a torque-splitter assembly, and a joint assembly. The torque-splitter assembly includes a spine assembly, a first trunion, and a second trunion. The spline assembly is configured to receive the drive shaft through a first opening. The spline assembly has a first plurality of outer splines oriented in a first direction and a second plurality of outer splines oriented in a second direction different from the first direction. The first trunion is disposed about the first plurality of outer splines. The second trunion is disposed about the second plurality of outer splines.

Abstract: According to one embodiment, a flapping lock for a rotor system includes a downstop, a flapping stop, and an actuator. The downstop is in mechanical communication with a shaft. The flapping stop is in mechanical communication with a rotor hub. The actuator is operable to move the downstop towards the flapping stop.

Abstract: A method of making a composite rotor yoke includes preparing a molded rotor yoke in a closed cavity tool and possibly machining at least one portion of the molded rotor yoke to form the rotor yoke. In the preferred embodiment, preparing the molded rotor yoke is accomplished by applying layers of uncured low-flow composite material and a layer of uncured high-flow adhesive; substantially enclosing the uncured molded rotor yoke in the closed cavity tool; applying pressure so as to compress the uncured molded rotor yoke; and curing the uncured molded rotor yoke. During the curing process, the high-flow adhesive bleeds out of the molded rotor yoke, thereby preventing marcels from forming through movement of the low-flow composite material.

Abstract: A temperature adaptive fluid damping system is provided. One embodiment of the temperature adaptive fluid damping system comprises two fluid chambers, a piston in fluid communication with the fluid chambers, and a fluid path between the fluid chambers. An elastomeric retaining element adjacent to the fluid path is constrained to deform substantially perpendicular to the fluid path, so that the retaining element is operable to vary the cross-sectional area of the fluid path inversely to a change in temperature.

Abstract: A system and method to amplify displacement includes a housing forming a cylindrical chamber having an elastomeric material disposed therein. The chamber being sealed with a first membrane and a second membrane. The first membrane being attached to a first end having and the second membrane being attached to a second end, the first end having a greater diameter than the second end. The method including producing an input displacement with a driver attached to the first membrane, which in turn results in an amplified output displacement at the second end.

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.

Abstract: A blade-pitch control system for controlling a pitch angle of blades on a rotor has an input swashplate assembly having non-rotating and rotating portions, the rotating portion being operably connected to blade grips. A feedback swashplate assembly has non-rotating and rotating portions, the rotating portion being connected to the yoke for movement with the yoke during flapping of the yoke. Linear actuators connect the non-rotating portion of the input swashplate assembly to the non-rotating portion of the feedback swashplate assembly. Motion of the yoke during flapping causes a corresponding motion of the feedback swashplate assembly and input swashplate assembly for providing selected pitch-flap coupling between flapping motion of the yoke and pitch motion of the grips.

Abstract: According to one embodiment, a flapping lock for a rotor system includes a downstop, a flapping stop, and an actuator. The downstop is in mechanical communication with a shaft. The flapping stop is in mechanical communication with a rotor hub. The actuator is operable to move the downstop towards the flapping stop.

Abstract: According to one embodiment, a rotor blade rotation system includes a hub, a rotor blade in mechanical communication with the hub and pivotable about an axis of rotation, a swashplate, a pitch link, and an actuator. The swashplate includes a rotating portion and a non-rotating portion. The pitch link is coupled to the rotating portion of the swashplate and in mechanical communication with the rotor blade. The actuator is coupled to the non-rotating portion of the swashplate and operable to reposition the swashplate from a first position to a second position such that the pitch links pivot the rotor blade from a deployed position to a folded position.

Abstract: According to one embodiment, a method comprises calendering an elastomeric material into an elastomeric layer having a thickness that is more uniform than the elastomeric material prior to the calendaring. After calendaring, the elastomeric layer is vulcanized to a composite shim comprising at least one reinforcement layer and at least one layer of adhesive.

Abstract: According to one embodiment, a rotor system includes an anti-rotation sleeve featuring an outer recess portion and a tilt sleeve positioned about the anti-rotation sleeve and having an opening therethrough. A first swashplate ring is positioned about the tilt sleeve and features an inner recess portion. An anti-rotation mechanism is disposed through the opening and at least partially in the outer recess portion and the inner recess portion. The anti-rotation mechanism is operable to prevent the first swashplate ring from rotating about the anti-rotation sleeve. A second swashplate ring is positioned about the first swashplate ring and rotatable about the anti-rotation sleeve.

Abstract: According to one embodiment, a rotor blade rotation system includes a hub, a rotor blade in mechanical communication with the hub and pivotable about an axis of rotation, a swashplate, a pitch link, and an actuator. The swashplate includes a rotating portion and a non-rotating portion. The pitch link is coupled to the rotating portion of the swashplate and in mechanical communication with the rotor blade. The actuator is coupled to the non-rotating portion of the swashplate and operable to reposition the swashplate from a first position to a second position such that the pitch links pivot the rotor blade from a deployed position to a folded position.

Abstract: A damper includes a housing that forms a fluidly sealed cavity for receiving a fluid therein. The fluid is configured to change fluid properties as electrical energy is induced. An electrical subsystem provides electrical energy to the fluid, which is monitored with a control subsystem. The method includes inducing the fluid with electrical energy to change the dampening effects of the damper in real time.

Abstract: A vibration attenuator for an aircraft has at least one weight mounted in a rotating system of a rotor hub of the aircraft, each weight being rotatable about an axis of rotation of the hub relative to the hub and to each other weight. Drive means are provided for rotating each weight about the axis of rotation at a selected speed for creating oscillatory shear forces that oppose and attenuate rotor-induced vibrations having a selected frequency. A vertically oriented vibration attenuator is configured to oppose and attenuate vertical rotor induced oscillatory forces that would otherwise travel vertical down the rotor mast and into the airframe.

Abstract: A rotor hub assembly and method for controlling movement of a rotor blade relative to a swashplate. The hub assembly having an attachment device operably associated with the rotor blade and the swashplate. The attachment device provides pivot and rotational blade movement relative to the swashplate. A dual spring-rate damper is operably associated with the attachment device. The damper switches between a first spring rate and a second spring rate during flight to control movement of the rotor blade. The method includes the process of switching the damper between the first spring rate and the second spring rate during flight.

Abstract: A tiltrotor aircraft includes a rotatable nacelle that supports a rotor assembly and is pivotally attached to the air-craft's fuselage. A wing extension attaches to an outboard section of the nacelle. The wing extension provides additional yaw control during helicopter mode and additional lift during airplane mode. A method for controlling at least a portion of yaw movement includes positioning the rotor assembly in helicopter mode, creating rotor wash with the rotor assembly, and pivotally rotating the wing extension in the rotor wash.