Abstract: Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed is an adjustable propeller that may alter shapes during operation or rotation of the propeller such that the sound generated by the rotation of the propeller changes. The propeller may include multiple sections and joints that allow movement of the sections in any direction. Likewise, the propeller may include one or more sound flaps that may be opened or closed to further alter the sound generated as the propeller rotates.

Abstract: A rotor system including a hub; a rim configured to rotate about the hub, the rim including an interior surface and an engagement surface; a plurality of rotor blades extending from the hub and coupled to the interior surface of the rim; and one or more outer drive gears disposed adjacent to the engagement surface of the rim; each of the one or more outer drive gears including a plurality of teeth for engaging the engagement surface of the rim; wherein the one or more outer drive gears are configured to rotate the rim such that the plurality of rotor blades rotates about the hub. Other aspects provide an aircraft rotor system and methods of operating an aircraft rotor system.

Abstract: A helicopter rotor include a blade, a rotor hub which supports the blade, and a lead-lag angle mechanism configured to change the lead-lag angle of the blade in synchronization with the rotation of the rotor hub. The lead-lag angle mechanism changes the lead-lag angle of the blade such that a circumferential speed of a blade tip of the blade (3) is slower on a forward side and faster on a backward side. The result is a helicopter, a helicopter rotor, and a control method of a helicopter that enable higher speed flight.

Abstract: A blade speed control apparatus and method. The apparatus includes a rotor assembly a first blade assembly movably attached to the rotor assembly at a first initial position, a second blade assembly movably attached to the rotor assembly at a second initial position, and a movement mechanism configured to move the rotor assembly in a first lateral direction along a y-axis such that a first angle exists between the first blade assembly with said respect to the second blade assembly. The movement mechanism is configured to move a portion of the rotor assembly in a first lateral direction along a y-axis such that a first angle exists between the first blade assembly with said respect to the second blade assembly. The first angle does not comprise an angle of 180 degrees.

Abstract: The system and method of the present application relate to a lead/lag damper for a rotorcraft. The lead/lag damper is configured to harvest power from the lead/lag oscillatory motions of rotor blades with an electromagnetic linear motor/generator. Further, the lead/lag damper is configured to treat the lead/lag motions with the electromagnetic linear motor/generator. The system and method is well suited for use in the field of aircraft, in particular, helicopters and other rotary wing aircraft.

Abstract: Helicopter blades each have a piston connected to it. The pistons are movable within a cylinder between innermost and outermost positions. The hydraulic fluid of each cylinder is connected to other cylinders by a hydraulic tube or through a manifold. A drive bar moving synchronously with the blades is connects to the cylinders. As the helicopter moves in flight the force of the wind against a blade causes a piston to move inwardly. This causes fluid to be expelled from the cylinder into the another cylinder by way of the hydraulic tube causing other piston to be moved outwardly. Meanwhile the other piston, because it is moving with the wind, is exerting an opposite effect on the other piston. The result is a tendency for the blades to approach an equilibrium condition with respect to the wind forces to minimize the shocks to the overall system.

Abstract: A pump has an impeller with a circular series of airfoil vanes rigidly mounted thereon. The impeller is mounted in a casing which has a radially outwardly increasing internal axial extent, such that fluid flowing through the pump has a less constricted path peripherally of the pump chamber than centrally of the pump chamber. In another aspect of the invention, the impeller comprises two axially adjacent series of vanes separated by a radially extending partition which divides the interior of the pump casing into a vacuum chamber and a pressure chamber interconnected by a hole formed in the center of the partition. At least one of the central partition and the impeller plate are conical in shape, thereby to impart a radially outwardly expanding axial extent to the vacuum chamber, and a decreasing axial extent to the pressure chamber.