In-plane sweep wind turbine blades and devices using the same and methods for their manufacture

Rotor blade (108) for a wind power plant, with a torsionally rigid foot (114), a forward sweep with respect to an elasticity axis (E) in an inner section (112) of the rotor blade and a backward sweep in an outer section (116) of the rotor blade, characterized in that the forward sweep is located at the root (114) of the rotor blade, the forward sweep is defined as an angle extending between the elastic axis (E) at the inner portion (112) of the rotor blade and an axis of pitch (P) of the rotor blade, and wherein the backward sweep is defined as an angle which extends between the elasticity axis (E) at the outer section (116) of the rotor blade and the pitch axis (P) of the rotor blade.