Patent ID: 6619585
Filing Date: 2003-09-16
Classification: B64C

Abstract:
Single-blade rotor for helicopters of the type comprising:a mast (7) with vertical rotation axis Yâ€”Y provided with an opposing coaxial pair of pins (7a) along an axis Xâ€”X, orthogonal to the rotation axis Yâ€”Y; the mast (7) having a top: a hub (1) of the rotor joined to the mast (7) and provided with a support (14) for a blade (8); a single blade (8)â€”operated by conventional means (10) connected to a suitable lever (9) of the blade (8)â€”joined to the support (14) by a pitch hinge that allows small rotations around the blade's longitudinal axis Aâ€”A; a counterweight (13) made up of a profiled mass located at one end of an arm (12) which terminates, at the other end of the same arm, with a hub (11) of the counterweight (13) used to hinge the said counterweight to the hub (1) of the rotor, wherein said rotor rotates around an axis Yâ€²â€”Yâ€²; pins (6) for hinging the hub (11) of the counterweight (13) to the hub (1) of the rotor, wherein the joining of the centre of the pins (6) with the centre of mass of the counterweight (13) determines a direction Câ€”C. characterized by the fact that: a) the hub (1) of the rotor can rotate around the axis Xâ€”X; b) the hub (11) of the counterweight (13) is hinged to the hub (1) of the rotor with the possibility of oscillation, with friction, around an axis Wâ€”W parallel to the axis Xâ€”X, underlying it; c) the inclination of the hub (1) of the rotor around the axis Xâ€”Xâ€”caused by a variation of the blade's coning angle &bgr;â€”does not determine the corresponding inclination of the counterweight (13), whose rotation plane remains orthogonal to the rotation axis Yâ€²â€”Yâ€² of the rotor; d) means for causing the displacement of the rotor centre of mass with respect to the rotation axis Yâ€²â€”Yâ€² and along the direction Câ€”C according to the inclination of the hub (1) of the rotor around the axis Xâ€”X with subsequent balance of the lift componentâ€”normal to the rotation axis of the rotor Yâ€²â€”Yâ€²â€”of the blade (8) and the inertial forces; e) friction devices positioned between the hub (1) of the rotor and the hub (11) of the counterweight (13) assure that the inclination of the rotation plane of the blade (8) around the axis Xâ€”Xâ€”caused by a cyclic variation of the pitch of the blade (8)â€”determines a simultaneous corresponding inclination of the rotation plane of the counterweight (13), with subsequent inclination of the rotation axis Yâ€²â€”Yâ€² of the rotor.