A vibration attenuator for a rotor of an aircraft has a first ring with an eccentric weight, a coaxial second ring with an eccentric weight, and a central ring coaxial with the first and second rings and located therebetween. A first post extends from the first ring toward the central ring and is received in a first arcuate groove formed on the central ring, whereas a second post extends from the second ring toward the central ring and is received in a second groove formed on the central ring. A motor is configured for driving the central ring in rotation about the axis relative to the motor. The grooves are equal in length, and a center of the first groove is located on an opposite side from a center of the second groove. Rotation of the central ring by the motor causes rotation of the first and second rings.

A vibration attenuator for a rotor of an aircraft has a housing adapted for rotation with the rotor about an axis. A first ring is rotatably carried within the housing on a first bearing, a first weight being coupled to the first ring for rotation therewith relative to the housing about the axis. A second ring is rotatably carried by the first ring on a second bearing, a second weight being coupled to the second ring for rotation therewith relative to the housing and to the first ring. A first motor is configured for rotating the first ring relative to the housing, and a second motor is configured for rotating the second ring relative to the housing and to the first ring. The first and second motors are operated to rotate the weights within the housing and position the weights relative to each other for attenuating vibrations.

A vibration suppression unit for an aircraft comprising a vibration control frame adapted to be mounted to the aircraft and to rotate about a central axis, a first motor configured to rotate the vibration control frame about the central axis, a second motor configured to rotate a first and second center of mass about a first and second axis or rotation, a third motor configured to adjust a variable distance between the first and second centers of mass and the first and second axis of rotation, respectively, and a controller for receiving input signals and outputting command signals to the first, second and third motors.

Systems and methods relate to a vertical takeoff and landing (VTOL) platform that can include a stator and a rotor magnetically levitated by the stator. The rotor and stator can be annular, such that the rotor rotates about a rotational axis. The stator can include magnets that provide guidance, levitation, and drive forces to drive the rotor, as well as to control operation of rotor blades of the rotor that can be independently rotated to specific pitch angles to control at least one of lift, pitch, roll, or yaw of the VTOL platform. Various controllers can be used to enable independent and redundant control of components of the VTOL platform.

Spring-integrated rotors are disclosed. A disclosed example apparatus includes a bracket defining a first rotational axis and coupled to a motor for rotating the bracket about the first rotational axis, a pivot body defining a second rotational axis extending along a direction different than the first rotational axis, the pivot body coupled to the bracket for rotation about the second rotational axis, and at least one spring device positioned at the bracket, the at least one spring device urging the pivot body toward a central position when the bracket is rotating.

A hydroelastic damper comprising at least a first resilient assembly that is provided with a first inner strength member engaged at least in part in a first outer strength member, a first resilient member providing resilient return for the first outer strength member and the first inner strength member towards a rest position (POSREP). The hydroelastic damper comprises at least one hydraulic assembly provided with a first hydraulic chamber and a second hydraulic chamber in communication with each other via a connection provided in a first wall of the hydraulic assembly. A first floating piston is movable at least in translation along the longitudinal axis relative to the first inner strength member and to the first outer strength member, the first hydraulic chamber being defined at least by the first floating piston and the first wall in order to protect the first resilient member.

A damper assembly includes a housing defining at least one or more cavities. A piston is in operable communication with the housing. A rod end is operatively coupled to the piston, the rod end having at least two cartridges.

Pendulum dampers are described. The pendulum dampers include a damper body having a first end and a second end, with an axial direction defined between the first end and the second end with a heater bore passing through the damper body in the axial direction from a tail port at the second end toward the first end and a cartridge heater installed within the heater bore, the cartridge heater configured to generate heat and heat a material of the damper body.

A rotor for a hover-capable aircraft is described, comprising: a hub rotatable about an axis and, in turn, comprising a plurality of blades; a mast connectable to a drive member of the aircraft and operatively connected to the hub to drive the hub in rotation about the axis; and damping means for damping vibrations transmitted to the mast, which comprise a mass designed to oscillate in a plane transversal to the axis so as to contain flexural vibrations of the mast generated by rotation of the blades; the damping means also comprise elastic means having a desired stiffness along the axis and operatively connected to the mass to contain vibration of the mast along the axis.

A vibration suppression unit for an aircraft comprising a mass having a center of mass, a first rotor, a second rotor, a first coupling between the first rotor and the mass, a second coupling between the second rotor and the mass, the first and second couplings having first and second coupling centers offset perpendicularly from a central axis of rotation by different radial distances and offset in axially from the center of mass with respect to the central axis by different axial distances, the first and second coupling centers having a selectively variable displacement angle defined by the angle between lines extending between the central axis of rotation and the first coupling center and the second coupling center, respectively, wherein the first rotor and the second rotor are controllable to produce a vibration control force vector having a controllable magnitude and frequency about the central axis.