An aircraft is provided including an airframe, an extending tail, a counter-rotating, coaxial main rotor assembly having an upper rotor assembly and a lower rotor assembly, and a translational thrust system including a propeller positioned at the extending tail. The translational thrust system is configured to provide translational thrust to the airframe when the aircraft is in a non-autorotation state and to generate power when in an autorotation state. A gearbox interconnects the propeller and the main rotor assembly to drive the main rotor assembly and the translational thrust system in the non-autorotation state. When the aircraft is in autorotation, the power generated by the propeller drives rotation of the main rotor assembly via the gearbox.

Dual rotor, rotary wing aircraft

A cyclic and collective control system is provided for controlling rotor pitch in a rotary wing aircraft. The rotor blades are pivotally mounted on a hollow, spinning shaft. An angularly and vertically displaceable control shaft is mounted with the spinning shaft and carries a rotatable control hub at its end. The control hub is coupled through pitch link rods to the rotor blades. When the control shaft is displaced vertically within the spinning shaft, the rotor blade pitch is changed collectively. When the control shaft is displaced angularly relative to the spinning shaft, the rotational plane of the control hub becomes skewed relative to the rotor axis. This has the effect of changing the pitch of the rotor blades in accordance with their rotational position around the rotor axis and has the further effect of providing cyclic control.

System and method for providing cyclic and collective pitch control in a rotary wing aircraft

A main rotor blade assembly for a rotary wing aircraft is provided including a main rotor blade root region, a main rotor blade inboard region arranged outboard of said main rotor blade root region, a main rotor blade main region arranged outboard of said main rotor blade inboard region, and a main rotor blade tip region arranged outboard of said main rotor blade main region. At least one of chord, twist, sweep, airfoil shape, and thickness/chord of the main rotor blade assembly has been optimized to achieve balanced high speed forward flight and hover relative to both efficiency and high thrust capability.

A rotor for use in an aircraft includes an inner hub; and a plurality of blades arranged around the inner hub, each of the plurality of blades comprising an inner structural member; an outer blade shell surrounding the inner structural member; and a centering block located at a base of the inner structural member proximal to the inner hub, wherein the centering block is located between a first lateral portion of the inner structural member and a second lateral portion of the inner structural member, wherein the centering block is further connected to the outer blade shell, and wherein the centering block allows the outer blade shell to rotate about an axis approximately corresponding to the inner structural member.

Rotor with blades including outer blade shell and inner structural member

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with an upper blade and a lower rotor assembly with a lower blade. A first antenna in one of upper blade and the lower blade, and a second antenna in the other of the upper blade and the lower blade. An oscillator to apply an excitation signal to the first antenna. A blade proximity monitor to monitor a magnitude of the excitation signal and an output signal from the second antenna to determine a distance between the upper blade and the lower blade.

Tip clearance measurement of a rotary wing aircraft

A low vibration helicopter rotor including a four-bar linkage arrangement which permits the straight line connecting the center of gravity of each pair of diametrically opposed rotor blades to intersect the rotor hub geometrical center at all cyclic conditions.

Edward W. Glatfelter

Papers

Low vibration helicopter rotor