The rotating plate of the system is fixed in rotation with the rotor by a driver with two rigid driving tracks extending axially and diametrically opposite in being fixed in rotation with the rotor. Each track engages with one of two driving fingers fixed in rotation with the rotating pl
The rotor comprises, for each blade, an inner and an outer flap stop which are fixed to the blade and have a bearing surface which is planar with a cylindrical portion, facing an inner and an outer flap stop fixed to the hub and with torus-shaped bearing surfaces with their convexness fa