Abstract: Helicopter rotor blade constructed of composite materials has a structural core (1) and a covering of profiled cladding (8). The structural core (1) includes all the structural elements of the blade, while the covering of the cladding (8) is a non-stress-bearing covering comprising an external rigid and thin shell (9a-9b), with the desired aerodynamic porfile, and a layer (10a-10b) of a ligth and flexible comformable non-stress-bearing material, such as a foam, ensuring the filling between the structural core (1) and the external shell (9a-9b). The foam layer (10a-10b) absorbs and compensates for the differences in shape between the contour of the structural core (1) and the precise aerodynamic profile of the non-stress-bearing external shell (9a-9b). The blade covering is expendable and evolutive spanwise as well as chordwise, with an external shell exhibiting an excellent surface condition, good erosion behavior and impact resistance, and easy to repair.