Rotor for a hover-capable aircraft

A rotor (3, 3') for an aircraft (1) is described that has a mast (50), an attenuating device (7, 7') to attenuate the transmission of vibrations from the mast (50) in a plane orthogonal to the first axis (A), and a transmission device (15) interposed between the mast (50) and the attenuating device (7, 7'); the attenuating device (7; 7') comprises a first and a second mass unit (8, 9) with a first and a second mass (10, 11) rotatable about the first axis (A) with a first and a second rotational speed ((N-1)*Ω; (N+1)*Ω), two control units (40) operable to cause an additional rotation of at least one of the first and second masses (10, 11), and a first and a second support assembly (41, 42) carrying the first and second masses (10, 11); each control unit (40) controls the angle between the first and second masses (10, 11) and comprises a set of drive gear teeth (55, 55') integral with the first support assembly (41, 42), a cogwheel (56) with a set of control gear teeth (57) meshing with the drive gear teeth (55, 55'), and an actuator (58) to cause the rotation of the cogwheel (56) about a second axis (F) and of the first mass (10, 11) about said first axis (A) .