Blade of composite materials and its manufacturing process

Blade essentially of composite materials, particularly for a multi-blade propeller of variable pitch and with individually removable blades, used in particular as the tail rotor, preferably streamlined, of a rotorcraft such as a helicopter, comprising:

• a shell (4) with an aerodynamic profile, having a suction face covering (4b) and a pressure face covering (4a) that extend from the leading edge (5) to the trailing edge (6) of the blade and along which trailing edge they are connected to one another, the shell (4) comprising at least one layer of fabric of fibres with high mechanical strength agglomerated by a polymerised synthetic impregnation resin, and having an internal end formed into a blade footing (3),
• a spar (8, 10a, 10b) with a longitudinal axis substantially parallel to that of the blade, and comprising at least one elongated bundle (10a, 10b) of rovings of fibres with high mechanical strength agglomerated by a polymerised synthetic resin, the largest portion of which is housed in the shell (4) and fixed by adherence of its suction face surface directly against the internal face of the opposite portion of the suction face covering (4b) of the shell, and an inner end portion of which, emerging from the shell (4) and passing through the blade footing (3), forms a root portion (8) flexible in torsion and flexion, arranged in a loop that surrounds, by its internal end, a single attaching socket (9), by which the blade is designed to be individually attached to a hub,
• a filling (12a, 12b, 12c) placed in the shell (4), between the latter and the spar (8, 10a, 10b), and
• a member (24) for controlling the pitch of the blade, which is integral with the blade footing (3) and designed to be mounted in rotation upon the hub about the longitudinal axis of the blade and to apply to the shell (4) a twisting moment substantially centered on the longitudinal axis of the spar, characterised in that the spar is centered on the longitudinal axis (AA) of the blade and each bundle (10a, 10b) of the spar is of a single piece, with a substantially rectangular cross-section, and also fixed, in its portion housed in the shell (4), by adherence of its pressure face surface directly to the inner face of the opposite portion of the pressure face covering (4a) of the shell (4), and in that the filling includes at least two filling bodies (12a, 12c), one of which (12a) is arranged between the spar (10a, 10b) and the leading edge (5) and the other (12c) between the spar (10a, 10b) and the trailing edge (6).