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 data recording and transmission method and system for use in balancing a propeller of an aircraft. The method comprises operating the propeller in-flight, receiving, during operation of the propeller in-flight, vibration data associated with the propeller, retrieving, from a non-volatile memory on-board the aircraft, configuration data associated with the propeller, and transmitting the vibration data and the configuration data to a data processing device configured to determine a balancing solution for the propeller based one the vibration data and the configuration data.

A gimbaled rotor assembly for an aircraft. The gimbaled rotor assembly including a static mast; a spherical bearing comprising an inner component and an outer component pivotable relative to each other about a bearing focus, the inner component fixedly coupled to the static mast; a rotor hub rotatably coupled to the outer component, allowing for relative rotation of the rotor hub about a rotor axis and for pivoting together with the outer component about the bearing focus; and a primary hub spring coupling the outer component to the static mast and configured for opposing pivoting of the rotor hub about the bearing focus from a neutral position.

A rotor-regulation system includes a rotor comprising a plurality of blades, a mechanically driven hydraulic pump, a rotor drive shaft operable to drive the rotor and the mechanically driven hydraulic pump, and a throttling valve coupled to the mechanically driven hydraulic pump and operable to modulate rotation of the rotor.

A gimbaled rotor assembly for an aircraft. The gimbaled rotor assembly including a static mast; a spherical bearing comprising an inner component and an outer component pivotable relative to each other about a bearing focus, the inner component fixedly coupled to the static mast; a rotor hub rotatably coupled to the outer component, allowing for relative rotation of the rotor hub about a rotor axis and for pivoting together with the outer component about the bearing focus; and a primary hub spring coupling the outer component to the static mast and configured for opposing pivoting of the rotor hub about the bearing focus from a neutral position.

A propeller provided with interchangeable blades, and to a method of mounting such interchangeable blades on the propeller. The propeller comprises a hub, fastening fittings, rotation guide devices for guiding the fastening fittings in rotation relative to the hub, locking parts, and blades. The fastening fittings are configured to be assembled into the hub from the inside of the hub, and the locking parts lock respective ones of the fastening fittings onto the hub. The blades are fastened to respective ones of the fastening fittings outside the hub and can thus easily be replaced with other blades without removing the propeller.

A propeller assembly with at least two propeller blades that are interconnected by associated connection means, the associated connection means defining a common pitch axis for the at least two propeller blades in operation, each one of the at least two propeller blades comprising associated leading and trailing edges that define a respective chord and quarter chord line thereof, wherein the common pitch axis is arranged with a predetermined offset relative to the quarter chord line of each one of the at least two propeller blades, and wherein the associated connection means is adapted to enable, at least in operation in a non-axial inflow field, a passive pitch adjustment of the at least two propeller blades around the common pitch axis.

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. A vibration attenuator having weights rotating about separate axes offset from each other.

Systems and methods to actively control vibrations affecting an aerial vehicle are described. Vibrations affecting a location of interest on an aerial vehicle may be measured, and phases of one or more propellers of the aerial vehicle may be determined. Based on the measured vibrations and determined phases of propellers, adjustments to the phases of the propellers may be determined to modify the vibrations affecting the location of interest. In this manner, vibrations at a location of interest on an aerial vehicle may be reduced, minimized, increased, induced, or otherwise modified as desired.

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.