The present invention relates to a free propeller assembly structure and an aircraft structure has the free propeller assembly. The free propeller assembly structure has at least one free propeller assembly. Each of the at least one free propeller assembly has a circular shaft, a main rotor, a signal transmitting device, and a rotor blade assembly. The main rotor has a shaft hole and multiple blade mounting structures radially disposed. Each blade mounting structure is provided with a positioning recess for mounting a driving motor in each positioning recess. The signal transmitting device includes multiple signal transmitters that are able to transmit interpretable electronic signals or photonic signals. The rotor blade assembly includes at least two rotor blades. One end of each rotor blade is connected with an open end of the positioning recesses of a corresponding one of the blade mounting structures

An aircraft rotor system including a hub having a hub axis about which the hub is configured to rotate; a plurality of rotor blades configured to extend from the hub and rotate about the hub axis, at least one of the rotor blades rotatable about a respective pitch change axis; wherein the hub is configured to be rotated about the hub axis only by the plurality of rotor blades. Another aspect includes a method of operating the rotor system.

An actuator assembly comprising an output member rotatable about an output axis, first and second actuators each having an axis of rotation, a drive motor and a hold motor, first and second linkages between each of the first and second actuators and the output member, wherein a torque produced by a drive motor is summed through the linkages at the output member when the respective hold motor is restrained from rotating, and wherein the respective hold motor may be selectively released so that it rotates with a failure of the respective drive motor, and wherein one of the first or second actuators may be driven to selectively rotate the output member with a failure of the drive motor of the other of the first or second actuators. The assembly may comprise a third actuator linked to the output member in the same manner as the first and second actuators.

A rotor system for an aircraft including a driving member; an externally driven rim configured to be rotated by the driving member; a hub having a hub axis, the hub including a rotatable housing and a non-rotatable housing; a plurality of rotor blade assemblies rotatably coupled to the rotatable housing of the hub and the externally driven rim such that rotation of the externally driven rim rotates the plurality of rotor blade assemblies about the hub axis, each rotor blade assembly having a rotor blade rotatable about a respective pitch change axis; and a pitch control mechanism operably associated with the hub and the plurality of rotor blade assemblies, wherein, actuation of the pitch control mechanism rotates each rotor blade assembly about the respective pitch change axis to collectively control the pitch of the rotor blade, thereby generating a variable thrust output. Also, a method of operating the rotor system.

There is provided a training system capable of performing work. The system has a shape memory alloy (SMA) actuator exhibiting a generally planar transformational behavior. The system further has one or more heating elements for transforming the SMA actuator from an original shape to a trained shape, thereby performing work.

A rotor system for an aircraft including a driving member; an externally driven rim configured to be rotated by the driving member; a hub having a hub axis, the hub including a rotatable housing and a non-rotatable housing; a plurality of rotor blade assemblies rotatably coupled to the rotatable housing of the hub and the externally driven rim such that rotation of the externally driven rim rotates the plurality of rotor blade assemblies about the hub axis, each rotor blade assembly having a rotor blade rotatable about a respective pitch change axis; and a pitch control mechanism operably associated with the hub and the plurality of rotor blade assemblies, wherein, actuation of the pitch control mechanism rotates each rotor blade assembly about the respective pitch change axis to collectively control the pitch of the rotor blade, thereby generating a variable thrust output. Also, a method of operating the rotor system.

An aerial vehicle is described herein. The aerial vehicle includes a lift mechanism that includes a rotor blade assembly coupled to a motor assembly. The rotor blade assembly includes a plurality of rotor blades that are pivotably coupled to a rotor blade clamping mechanism. The rotor blade clamping mechanism includes an upper paddle clamp that is coupled to a lower paddle clamp. The upper paddle clamp includes a center protrusion and a plurality of blade support protrusions extending outwardly from the lower outer surface. The center protrusion includes a center shaft aperture sized and shaped to receive a motor shaft therein. Each blade support protrusion is sized and shaped to be inserted through a corresponding positioning aperture of a corresponding rotor blade. The lower paddle clamp includes a central recess to receive the center protrusion therein and a plurality of blade recesses to receive a corresponding blade support protrusion therein.

A rotor for a hover-capable aircraft is described that comprises: a hub rotatable about a first axis and at least two blades hinged to the hub; each blade comprises a main portion hinged to the hub and a tip portion, which is arranged radially outermost with respect to first axis with respect to the corresponding main portion; the tip portion of each blade is movable with respect to the corresponding main portion of that blade; the tip portion of each blade is selectively movable with respect to the corresponding main portion of that blade between a first position, in which it defines a dihedral or anhedral angle with respect to the corresponding main portion; and a second position, in which it defines a positive or negative sweep angle with respect to the corresponding main portion.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the shape of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more joints that adjust to alter the shape of the propeller blade. The altered shape of the propeller blade causes the propeller to generate different frequencies of sound as it rotates. By altering multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel or reduce the total sound generated by the aerial vehicle, and/or alter the total frequency generated.

An actuator assembly comprising an output member rotatable about an output axis, first and second actuators each having an axis of rotation, a drive motor and a hold motor, first and second linkages between each of the first and second actuators and the output member, wherein a torque produced by a drive motor is summed through the linkages at the output member when the respective hold motor is restrained from rotating, and wherein the respective hold motor may be selectively released so that it rotates with a failure of the respective drive motor, and wherein one of the first or second actuators may be driven to selectively rotate the output member with a failure of the drive motor of the other of the first or second actuators. The assembly may comprise a third actuator linked to the output member in the same manner as the first and second actuators.