A rotor includes a rotor axis, two elongate blades, a hub on the rotor axis, and a rotational drive system on the rotor axis. The hub supports the blades for pivotation relative thereto, including folding one blade over the hub between radial opposition with the other blade about the rotor axis and alongside the other blade. The rotational drive system supports the blades on the hub for rotation about the rotor axis, and supports the blades on the hub for teetering.

The present disclosure is directed to rotor assemblies for scissoring rotors, aircraft including the same, and associated methods. In one example, a hub assembly comprises: a first hub subassembly configured to rotate a first blade assembly about an axis of rotation in a first plane, a second hub subassembly configured to rotate a second blade assembly about the axis of rotation in a second plane, and a rotary guide configured to control an axial position of the second hub subassembly relative to the first hub subassembly about the axis of rotation. The rotary guide is configured to adjust the axial position as a function of a lifting force generated by the first blade assembly or the second blade assembly.

The present disclosure is directed to rotor assemblies for scissoring rotors, aircraft including the same, and associated methods. In one example, a hub assembly comprises: a first hub subassembly configured to rotate a first blade assembly about an axis of rotation in a first plane, a second hub subassembly configured to rotate a second blade assembly about the axis of rotation in a second plane, and a rotary guide configured to control an axial position of the second hub subassembly relative to the first hub subassembly about the axis of rotation. The rotary guide is configured to adjust the axial position as a function of a lifting force generated by the first blade assembly or the second blade assembly.

An elastomeric bearing assembly has a centrifugal force bearing axially captured relative to a sliding interface. The sliding interface has one or more low friction regions and one or more high friction regions. One or more piezo actuators are configured to force one or more corresponding high friction regions against the centrifugal force bearing when actuated. The sliding interface may have a circular shape, wherein the one or more low friction regions and the one or more high friction regions are alternating concentric segments of the sliding interface. The one or more high friction regions are recessed on the sliding interface relative to the one or more low friction regions.

A propeller assembly including a shaft having a rotational axis; a plurality of propellers connected to the shaft; means for deploying the plurality of propellers using a centrifugal force generated from a rotation of the shaft, so as to provide vertical thrust during a vertical take-off and landing of the aircraft; and means for restoring the propellers into a stowed configuration.

An exemplary length adjustable link includes a tube having an internal bore and internal surface, a first rod end having a first shaft disposed in a first end of the internal bore, a second rod end having a second shaft disposed in a second end of the internal bore, and a member threadably connecting the first rod end to the second rod end.

The rotary wing drone comprises at least one rotor carried by a drone structure, wherein the drone structure comprises a drone body and at least one group of arms comprising a plurality of arms rotatably mounted on the drone body about the same axis of rotation, between a deployed position for flight and a folded position for transport.

The rotary wing drone comprises at least one rotor carried by a drone structure, wherein the drone structure comprises a drone body and at least one group of arms comprising a plurality of arms rotatably mounted on the drone body about the same axis of rotation, between a deployed position for flight and a folded position for transport.

The present disclosure provides an unmanned flight system and a control system for an unmanned flight system. The unmanned flight system comprises: a body and a lift mechanism connected to the body, wherein the lift mechanism includes two rotor assembly arm structures respectively provided on two sides of the body, wherein each of the rotor assembly arm structures respectively includes: an arm, a pivotable rotor assembly, a motor for driving the rotor assembly to pivot about a pivot axis, and a motor base for mounting the motor, wherein one end of the arm is pivotally connected to one side of the body, the motor base is pivotally provided on the other end of the arm, and a rotational axis of the motor base is higher than a center of gravity of the unmanned flight system. The unmanned flight system according to the present disclosure can achieve a longer flight time, a simple rotor assembly structure, and easier overall assembly and maintenance.

Embodiments are directed to a high speed, vertical lift aircraft that has vertical take-off and landing (VTOL) capability and is capable of converting to a forward-flight mode (e.g., prop-mode). The rotors blades can be folded for high speed forward flight propelled by a turbine engine (e.g., jet-mode). The rotor blades on the tail sitter aircraft have a “stop-fold” capability, which means that the rotor blades are stopped in flight and folded back to reduce drag. This allows the tail sitter aircraft to achieve a higher speed than a tilt-rotor aircraft. In some embodiments, the tail sitter aircraft achieves both rotor-borne flight and jet-borne flight by having two separate engines. An additional advantage of the tail-sitter aircraft versus a horizontally oriented fixed engine aircraft is that supplemental jet thrust can be used for take-off if desired.