Rotor for a hover-capable aircraft

A rotor (3) for a hover-capable aircraft (1) is described that comprises: a hub (5) rotating about an axis (A) and, in turn, comprising a plurality of blades (9), a mast (6) connectable to a power unit of the aircraft (1) and operatively connected to the hub (5) to drive the hub (5) in rotation about said axis (A), and an attenuating device (15) to attenuate the transmission of vibrations from the mast (6) to the aircraft (1) parallel to said (A); the attenuating device (15), in turn, comprising a casing (20), a first mass (21) free to oscillate parallel to said axis (A) with respect to the casing (20) and elastically connected to the casing (20), a second mass (25) free to oscillate parallel to said axis (A), connection means (30) adapted to make the first and second masses (21, 25) integrally movable along said axis (A) when the angular speed (Ω) of the mast (6) assumes a first value (Ω1), and actuator means (35) activatable to decouple the first and second masses (21, 25) when the angular speed (Ω) of the mast (6) assumes a second value (Ω2), different from the first value (Ω1).