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: A blade pitch adjustment mechanism includes a pitch cylinder having a first face and pitch slots extending longitudinally from the first face, a blade sleeve having a second face and a blade slot extending longitudinally from the second face, the blade sleeve is configured to be rotationally positioned in the pitch cylinder with the second face located with the first face, wherein the blade slot and the pitch slots are cooperative to form keyway, corresponding to a discrete blade pitch, when the blade slot is aligned with a pitch slot.

Abstract: A rotor assembly includes a pitch spider, rotor blade assemblies, and pitch horn joints. The pitch spider has a body and pitch spider legs extending from the body. Each blade rotor assembly includes a rotor blade, a pitch adapter joined to the rotor blade and connecting the rotor blade to the rotor hub, and a pitch horn. Each pitch horn joint joins one of the rotor blade assemblies to a corresponding pitch spider leg. Each pitch horn joint includes a pitch horn joint bolt extending from the pitch horn of the rotor blade assembly to the pitch spider leg along a pitch horn joint axis, the pitch horn joint bolt fixed to the pitch horn; a spherical bearing having an inner ring and an outer ring; and a slider sleeve coupled to the spherical bearing, the slider sleeve enabling the pitch horn to translate along the pitch horn joint axis.

Abstract: A blade pitch adjustment mechanism includes a pitch cylinder having a first face and pitch slots extending longitudinally from the first face, a blade sleeve having a second face and a blade slot extending longitudinally from the second face, the blade sleeve is configured to be rotationally positioned in the pitch cylinder with the second face located with the first face, wherein the blade slot and the pitch slots are cooperative to form keyway, corresponding to a discrete blade pitch, when the blade slot is aligned with a pitch slot.

Abstract: A spherical bearing centrifugal force retention link includes an inboard spherical bearing to attach to a rotor hub and an outboard spherical bearing to attach to a rotor blade. In use, the inboard spherical bearing and the outboard spherical bearing react centrifugal force radially and a torsional moment of the centrifugal force link is substantially constant throughout the rotor blade pitch range.

Abstract: A spherical bearing centrifugal force retention link includes an inboard spherical bearing to attach to a rotor hub and an outboard spherical bearing to attach to a rotor blade. In use, the inboard spherical bearing and the outboard spherical bearing react centrifugal force radially and a torsional moment of the centrifugal force link is substantially constant throughout the rotor blade pitch range.

Abstract: An exemplary electric distributed propulsion system includes two or more rotors that are individually controlled by the rotational speed of associated motors, an input control connected to the associated motors to provide rotational speed control to the two or more rotors to produce a desired net thrust, and a logic connected to the input control and the associated motors, the logic for controlling speed and direction of the two or more rotors to achieve the desired net thrust and to avoid a motor speed condition.

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 rotor system includes a drive hub, a set of rotor blades extending radially from the drive hub, and a set of tension-torsion straps connecting the rotor blades to the drive hub. The drive hub has a rotor mast opening extending along a mast axis. The rotor system is configured to rotate about the mast axis. The drive hub further has a set of mounting slots for mounting the tension-torsion straps. The mounting slots are arranged along a circle around the drive hub, each mounting slot extending through the drive hub along a respective mounting axis. The mounting axis of each of the mounting slots is biased relative to the mast axis. The tension-torsion straps are mounted to the drive hub at their corresponding mounting slots.

Abstract: A rotor assembly includes a pitch spider, rotor blade assemblies, and pitch horn joints. The pitch spider has a body and pitch spider legs extending from the body. Each blade rotor assembly includes a rotor blade, a pitch adapter joined to the rotor blade and connecting the rotor blade to the rotor hub, and a pitch horn. Each pitch horn joint joins one of the rotor blade assemblies to a corresponding pitch spider leg. Each pitch horn joint includes a pitch horn joint bolt extending from the pitch horn of the rotor blade assembly to the pitch spider leg along a pitch horn joint axis, the pitch horn joint bolt fixed to the pitch horn; a spherical bearing having an inner ring and an outer ring; and a slider sleeve coupled to the spherical bearing, the slider sleeve enabling the pitch horn to translate along the pitch horn joint axis.

Abstract: An exemplary anti-torque system for a helicopter includes two or more electric fans rotatably mounted on a tail boom, the two or more electric fans rotatable about a longitudinal axis of the tail boom.

Abstract: Systems and methods include providing an aircraft with a ducted rotor assembly. The ducted rotor assembly includes a housing having a duct, a rotor drive mechanism coupled to a rotor system, and a plurality of stators that both structurally support the rotor drive mechanism within the duct of the housing and carry a fluid through internal fluid passages in the plurality of stators to provide cooling to the rotor drive mechanism. Some of the stators carry fluid to the rotor drive mechanism, where the fluid absorbs heat from the rotor drive mechanism, and some of the stators carry fluid away from the rotor drive mechanism. The rotor system generates an airflow over the stators carrying fluid away from the rotor drive mechanism to effect transfer between the fluid and the airflow.

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 method of controlling a tail rotor system includes pivoting a swashplate of the tail rotor system about an axis passing through a diameter of the swashplate. Pivoting the swashplate causes a first linkage of a first pair of linkages coupled between the swashplate and a collective crosshead to move in a first direction and a second linkage of the first pair of linkages coupled between the swashplate and the collective crosshead to move in a second direction that is opposite the first direction. The movement of the first and second linkages causes a plane of rotation of a pair of rotors of the tail rotor system to cant relative to a centerline of a mast of the tail rotor system. A tail rotor system is also disclosed.

Abstract: A method is provided in one example embodiment and may include positioning at least one nozzle within a hollow portion of a rotor blade at a distance associated with a span of the rotor blade and providing, via the at least one nozzle, a liquid foam mixture in the hollow portion, wherein the liquid foam expands and becomes a solid foam material that fills the hollow portion of the rotor blade. Another method is provided in another example embodiment and may include providing a plurality of openings for a rotor blade that are positioned proximate to a hollow portion of the rotor blade and providing a liquid foam mixture in the hollow portion of the rotor blade through at least one opening of the rotor blade, wherein the liquid foam mixture expands and becomes a solid foam material that fills the hollow portion of the rotor blade.

Abstract: A tension-torsion strap, for example for a rotor aircraft, including a continuous length of carbon fiber tow arranged in multiple loops to form an elongated member extending between opposing ends and a flexible cover encasing the carbon fiber tow.

Abstract: A transmission tilt control device includes a transmission rotatably coupled to an airframe of a helicopter, a rotor mast coupled to the transmission, and an actuator coupled between the transmission and the airframe. The actuator being configured to rotate the transmission fore and aft about a tilt axis that is perpendicular to an axis of rotation of the rotor mast.

Abstract: Systems and methods include providing an aircraft with a tail rotor system having a tail rotor housing that forms a cambered airfoil between an upper cambered surface and a lower cambered surface of the tail rotor housing. The cambered airfoil design of the tail rotor housing is capable of providing sufficient lifting force of an aircraft to offload the tail rotor during forward flight, thereby eliminating the need for a traditional vertical stabilizer or fin. The tail rotor blades of the tail rotor system are disposed within an aperture in the tail rotor housing, which minimizes or preferably eliminates exposure of the tail rotor blades to edgewise airflow typically encountered during forward flight, thereby allowing rigid rotor hubs, both in-plane and out-of-plane, to be used in the tail rotor system while also reducing noise output of the tail rotor system.

Abstract: An exemplary anti-torque system for a helicopter includes two or more electric fans rotatably mounted on a tail boom, the two or more electric fans rotatable about a longitudinal axis of the tail boom.