Inertial traction system based on counter-rotating masses (W) with a variable arm between a maximum value and a minimum value and rotating with an angular direction equal and opposed between each other in planes at least parallel between each other, comprising at least a rotor in order to keep the rotation of said pair of masses (W), means for varying said arm, controllable decoupling means between said rotor and said pair of masses (W), first control means in order to control at least said means for varying the arm in order to compose the respective centrifugal and/or Coriolis forces of the respective masses in order to generate impulses according to a movement line (V) so that a number or an intensity of said impulses is prevalent with respect to a single direction (I) of said line (V).