An aircraft tail rotor system includes a rotating pitch change shaft, a translating element, and a pitch change bearing assembly including a first bearing and a second bearing. The pitch change bearing assembly is operable to transmit movement of the translating element to the rotating pitch change shaft via the first bearing or the second bearing. A failure section is formed at an interface between the first bearing and the translating element. When the failure section decouples the first bearing from the translating element such that the first bearing does not transmit movement of the translating element to the rotating pitch change shaft, the second bearing transmits movement of the translating element to the rotating pitch change shaft.

An embodiment rotorcraft includes a main rotor, one or more flight controls connected to the main rotor and operational to control flight characteristics of the main rotor by pitching a nose of the rotorcraft upward, and a flight control computer (FCC) operable to determine an attitude command and to generate an adjusted attitude command by adjusting a magnitude of the attitude command according to an above ground level (AGL) altitude of the rotorcraft. The FCC is further operable to control a flight characteristic of the rotorcraft by sending the adjusted attitude command to one or more flight controls.

A rotor or propeller may have rotor blades and a passive pitch angle adjustment apparatus. The passive pitch angle adjustment apparatus may include levers, rods, and central rod. Levers may be connected to rotor blades and rotate them around a respective pitch axis. Rods may be connected to levers and mechanically link levers with each other via central point that is located outside rotor plane. Central rod may connect central point with base point that is located in a longitudinal direction of rotor axis. The passive pitch angle adjustment apparatus may enable a cyclic pitch adjustment of the rotor blades and block a collective pitch adjustment of the rotor blades.

An unmanned aerial vehicle (UAV) includes a central part, a frame assembly, and a propulsion assembly mounted to the frame assembly. The UAV also includes a servo mounted to the central part. The servo includes a driving apparatus, a control apparatus operably coupled with the driving apparatus, and a sensor configured to obtain operating parameters of the driving apparatus. The operating parameters include operating positions of the driving apparatus. The control apparatus is configured to control the driving apparatus to rotate to a predetermined position and stay at the predetermined position based on the operating positions of the driving apparatus obtained by the sensor.

An unmanned aerial vehicle (UAV) includes a central part, a frame assembly, and a propulsion assembly mounted to the frame assembly. The UAV also includes a servo mounted to the central part. The servo includes a driving apparatus, a control apparatus operably coupled with the driving apparatus, and a sensor configured to obtain operating parameters of the driving apparatus. The operating parameters include operating positions of the driving apparatus. The control apparatus is configured to control the driving apparatus to rotate to a predetermined position and stay at the predetermined position based on the operating positions of the driving apparatus obtained by the sensor.

The present invention discloses a rotor control system where rapid changes in rotor torque are transferred into moment forces acting about the blade pitch axis of a rotor blade in a thrust-generating rotor, to ultimately control the movements of a rotary wing aircraft. The moment forces acting on the rotor blade are transferred through a carefully adjusted damping member in order to allow rapid changes in rotor torque to create cyclic changes in blade pitch angle, while slow or permanent changes are cancelled out and affects the rotational speed and the thrust generated by the rotor, without permanently affecting the blade pitch angle of individual rotor blades.

The present invention discloses a rotor control system where rapid changes in rotor torque are transferred into moment forces acting about the blade pitch axis of a rotor blade in a thrust-generating rotor, to ultimately control the movements of a rotary wing aircraft. The moment forces acting on the rotor blade are transferred through a carefully adjusted damping member in order to allow rapid changes in rotor torque to create cyclic changes in blade pitch angle, while slow or permanent changes are cancelled out and affects the rotational speed and the thrust generated by the rotor, without permanently affecting the blade pitch angle of individual rotor blades.

A rotor system including a rotor hub, and a plurality of rotor blades. Each of the plurality of rotor blades includes a hub end. A plurality of rotor blade actuators is operatively connected to the hub end of a corresponding one of the plurality of rotor blades. A fairing is mounted to the rotor hub. The fairing includes an external surface and an internal surface defining an interior portion. The hub end and rotor blade actuator of each of the plurality of rotor blades is arranged in the interior portion. A cooling system is arranged in the interior portion. The cooling system includes a first heat exchanger thermally connected to each of the plurality of rotor blade actuators, a second heat exchanger mounted to the fairing, and at least one fluid conduit extending therebetween.

A rotor apparatus is provided and includes a first rotor shaft disposed to rotatably support a first rotor, a second rotor shaft disposed to rotatably support a second rotor and first and second bearing elements disposed to support the first rotor shaft within the second rotor shaft and to pre-load the first rotor shaft in one of tension and compression and the second rotor shaft in the other one of tension and compression.

A rotor apparatus is provided and includes a first rotor shaft disposed to rotatably support a first rotor, a second rotor shaft disposed to rotatably support a second rotor and first and second bearing elements disposed to support the first rotor shaft within the second rotor shaft and to pre-load the first rotor shaft in one of tension and compression and the second rotor shaft in the other one of tension and compression.