Rotorcraft rotor with blades hinged in flap and in lag

A rotorcraft rotor comprising a hub and at least two blades hinged relative to the hub about respective pitch axes, about respective flap axes, and about respective lag axes, the three axes coinciding at a hinge center for each blade, each blade being secured to a respective pitch lever, the rotor including for each blade a pitch control rod connected to the pitch lever via a first ball joint, and a common lag damper structure centered substantially on the axis of rotation of the rotor and connected to each of the blades, wherein the lag damper structure is secured to a respective lateral projection of each blade via a respective single second ball joint that is sufficiently close to the first ball joint connecting the pitch rod to the pitch lever to ensure that the lag damper system is relatively or completely insensitive to flap oscillations of the hinged blades, and wherein the common damper structure is not secured to the hub, in which the damper structure is formed by connecting together in pairs a plurality of identical damper units to form a frame, each damper unit comprising two outer strips having an inner strip extending therebetween, the strips being in the form of plane plates having the shape of elongate rectangles and extending parallel to one another, a first layer of elastomer connecting the top face of a first outer strip to the bottom face of the inner strip, and a second layer of elastomer connecting the top face of the inner strip to the bottom face of the other outer strip, the projecting outer end of the inner strip of each unit being rigidly secured to the end of the adjacent damper unit, and being rigidly secured to a ball joint connecting with the root of the corresponding blade.