Beam for attaching only one blade to a hub of a rotorcraft rotor with at least one further blade having a longitudinal axis of the blade, the rotorcraft rotor being defined by a rotation axis (z) of the hub and by a bending stiffness axis (y) which is orthogonal to the longitudinal axis of the blade and to the rotation axis (z) of the hub; said beam comprising for attaching the only one blade to the hub: • a hub connection portion for connecting the beam to the hub of the rotor; • a blade connection portion for connecting the beam to the blade of the rotor; characterized in that the beam further comprises: • a first flexure portion having the function of a discrete hinge performed by the structure in the first flexure portion of the beam located between the hub connection portion and the blade connection portion and having a bending stiffness about a first axis (yy, zz) which is orthogonal to the longitudinal axis of the blade, said bending stiffness being smaller than that of the hub connection portion and that of the blade connection portion; and • a shear portion having the function of a discrete hinge performed by the structure in the shear portion of the beam located between the hub connection portion and the blade connection portion; the shear portion having a shear stiffness along a shear axis which is orthogonal to the first axis (yy, zz) and parallel to either the rotation axis (z) of the hub and the bending stiffness axis (y) of the blade, which is orthogonal to the longitudinal axis of the blade and non-parallel to the remaining of the rotation axis (z) of the hub or to the bending stiffness axis (y), • said shear stiffness being smaller than the shear stiffness of the hub connection portion and the shear stiffness of the blade connection portion, in order to change the location of the virtual hinge that corresponds to the first flexure portion. • a hub connection portion for connecting the beam to the hub of the rotor; • a blade connection portion for connecting the beam to the blade of the rotor; characterized in that the beam further comprises: • a first flexure portion having the function of a discrete hinge performed by the structure in the first flexure portion of the beam located between the hub connection portion and the blade connection portion and having a bending stiffness about a first axis (yy, zz) which is orthogonal to the longitudinal axis of the blade, said bending stiffness being smaller than that of the hub connection portion and that of the blade connection portion; and • a shear portion having the function of a discrete hinge performed by the structure in the shear portion of the beam located between the hub connection portion and the blade connection portion; the shear portion having a shear stiffness along a shear axis which is orthogonal to the first axis (yy, zz) and parallel to either the rotation axis (z) of the hub and the bending stiffness axis (y) of the blade, which is orthogonal to the longitudinal axis of the blade and non-parallel to the remaining of the rotation axis (z) of the hub or to the bending stiffness axis (y), • said shear stiffness being smaller than the shear stiffness of the hub connection portion and the shear stiffness of the blade connection portion, in order to change the location of the virtual hinge that corresponds to the first flexure portion.