Abstract: A hub plate and helicopter rotor incorporating same made of a composite material and comprising a laminated disc constituted by layers of fiber cloth having high mechanical strength. A frame of the disc is made of aligned layers of the cloth with the weft or warp of the cloth extending radially in the direction corresponding to the direction of centrifugal force acting on the plate when in use. The aligned layers are positioned at the core of the structure and at least at the surface of the structure in the peripheral portion of the disc. The disc is enclosed by a belt of parallel threads consisting of fibers having high mechanical strength fitted on radially outwardly projecting parts of the disc in recesses formed in the outer edge of the parts, the recesses being open to the exterior.

Abstract: The invention relates to a device for damping the vibrations of a rotary-wing aircraft rotor. An annular weight is disposed concentrically of the rotor axis. This weight is supported by at least three resiliently deformable elements such as helical springs, radially biased in directions distributed regularly around the rotor axis. The inner ends of the springs directly bear on a part extending the rotor shaft axially. Their outer ends directly bear on the annular weight so that the spring apply statically balanced centrifugal thrusts to the annular weight. The springs are so still that they support the annular weight without substantially bending.

Abstract: The invention relates to a device for damping the vibrations of the rotor of a rotary-wing aircraft. This device comprises a flapping weight concentrated near the rotor axis and at least three resiliently deformable elements, such as helical springs. The deformable elements are radially biassed in directions regularly distributed around the rotor axis. The inner ends of the deformable elements directly bear on the flapping weight. Their outer ends directly bear on rigid structure elements, rigidly secured to the rotor hub, so that the biassed deformable elements apply statically balanced centripetal thrusts to the flapping weight.