In order to simplify the design of an aircraft turbo engine propeller while enhancing the safety function thereof related to control of the blade angle of attack, a propeller is provided comprising a secondary rotational coupling to couple in rotation, along the radial axis of the blade, the inner radial end of the blade root with a mechanical joining member of a blade angle of attack control device, the secondary coupling being designed and configured to be active in the event of failure of the main pin.

In order to simplify the design of an aircraft turbo engine propeller while enhancing the safety function thereof related to control of the blade angle of attack, a propeller is provided comprising a secondary rotational coupling to couple in rotation, along the radial axis of the blade, the inner radial end of the blade root with a mechanical joining member of a blade angle of attack control device, the secondary coupling being designed and configured to be active in the event of failure of the main pin.

A propeller includes a blade free to rotate. A first stop is positioned to mechanically engage one or both of a first portion of the blade and a first structure coupled to the blade when the blade is in a first position at a first end of the rotational range of motion. A second stop is positioned to mechanically engage one or both of a second portion of the blade and a second structure coupled to the blade when the blade is in a second position at a second end of the defined rotational range. The blade rotates to the first position against the first stop when the propeller is rotated in a first direction and to the second position against the second stop when the propeller is rotated in a second direction.

A rotor system of a tail-sitter aerial vehicle configured to rotate about an axis of rotation is provided including a rotor hub which rotates about the axis of rotation and at least one rotor blade operably coupled to the rotor hub. The at least one rotor blade is configured to rotate about a folding axis between an extended position where the at least one rotor blade is substantially within a plane perpendicular to the axis of rotation and a stowed position where the rotor blade is arranged out of the plane of at an angle less than ninety degrees to the axis of rotation.

A control system (10) for controlling the pitch of a propeller (50), the system comprising a propeller shaft (60), a blade swivel device (20) having a rotary control element (22) suitable for placing the blades (52) in an angular position corresponding to a desired propeller pitch, and a transmission (12) presenting an outlet member coupled in rotation with the rotary control element (22) of the blade swivel device (20).

The transmission (12) includes a variable speed drive (70) having drive, control, and outlet rotors that are coupled in rotation respectively with the propeller shaft (60), with a control member, and with the outlet member of the transmission.

By means of the variable speed drive (70), the speed of rotation of the outlet member of the transmission is a predetermined function of the speeds of rotation not only of the propeller shaft, but also of the control member.

A control system (10) for controlling the pitch of a propeller (50), the system comprising a propeller shaft (60), a blade swivel device (20) having a rotary control element (22) suitable for placing the blades (52) in an angular position corresponding to a desired propeller pitch, and a transmission (12) presenting an outlet member coupled in rotation with the rotary control element (22) of the blade swivel device (20).

The transmission (12) includes a variable speed drive (70) having drive, control, and outlet rotors that are coupled in rotation respectively with the propeller shaft (60), with a control member, and with the outlet member of the transmission.

By means of the variable speed drive (70), the speed of rotation of the outlet member of the transmission is a predetermined function of the speeds of rotation not only of the propeller shaft, but also of the control member.

A variable pitch bladed disc including a plurality of blades, each being of variable pitch about a blade axis of rotation and having a root, the plurality of blades including at least one first blade and at least one second blade, a plurality of rotor connecting shafts, each shaft having a root and a tip, the root of each blade being mounted on the tip of a corresponding rotor connecting shaft via a pivot so as to allow each blade to be rotated about the blade axis of rotation, the first blade having a first rotation axis inclination such that the rotation axis thereof is inclined in a fixed manner with respect to a radial axis passing through the root of the corresponding shaft, and the second blade has a second rotation axis inclination different from the first rotation axis inclination.

Methods and apparatus to retain a rotor blade are disclosed herein. An example apparatus includes a rotor blade coupled to a rotatable hub of an engine system. The rotor blade includes a root, a flange and a blade. The root and the flange are disposed inside a cowling, and the blade is disposed outside of the cowling. The example apparatus also includes a retainer disposed inside the cowling adjacent the flange. The flange is to engage the retainer to retain the rotor blade with the engine system.

An aircraft rotor system includes a rotating pitch change shaft which rotates about an axis, a translating element disposed within the rotating pitch change shaft and movable along the axis and a pitch change bearing assembly which transfers movement of the translating element to the pitch change shaft. The pitch change bearing assembly includes a primary bearing and a secondary bearing coupled to the rotating pitch change shaft via the translating element when the primary bearing is in a first mode. A thrust shoulder is coupled to the translating element. The thrust shoulder is movable into engagement with the secondary bearing in response to failure of the primary bearing such that in a second mode, movement of the translating element is primarily transferred to the pitch change shaft via the secondary bearing.

A blade pitch control assembly includes a pitch control actuator having a coarse actuator chamber having a coarse chamber area and a fine actuator chamber having a fine chamber area. The coarse chamber area is biased to a feather position. The assembly also includes a primary pitch control valve configured to control the flow of pressurised fluid to the coarse actuator chamber and the fine actuator chamber, respectively via a coarse fluid line and a fine fluid line. The assembly further includes a hydraulic protection system located between the actuator and the primary pitch control valve, configured to bypass the primary pitch actuator in response to a trigger. The hydraulic protection system has a hydraulic protection system valve located between the fluid lines and when activated fluidly connects the fluid lines to balance fluid pressure between the coarse chamber and the fine chamber.