Patent ID: 8668462

Claim:
A wind turbine rotor blade comprising a blade tip ( 10 ), a blade root ( 12 ), a leading edge ( 16 ), a trailing edge ( 18 ), a pressure side ( 32 ), a suction side ( 30 ) and a cross-section, which changes from the blade tip ( 10 ) to the blade root ( 12 ), wherein the cross-section in the middle ( 14 ) of the rotor blade is formed by an aerodynamic profile and is mainly circular at the blade root ( 12 ), and wherein the cross-section in a longitudinal portion of the rotor blade, the longitudinal portion being arranged between the blade root ( 12 ) and the middle ( 14 ) of the rotor blade, comprises: a convex pressure side portion ( 78 ), which extends from the leading edge ( 16 ) up to a pressure-side inflection point ( 80 ), a concave pressure side addition portion ( 82 ), which connects with the pressure-side inflection point ( 80 ) with a continuous curvature and extends up to the trailing edge ( 18 ), a convex suction side portion ( 72 ), which extends from the leading edge ( 16 ) up to a suction-side kink or inflection point ( 74 ), a suction side addition portion ( 76 ), which extends from the suction-side kink or inflection point ( 74 ) up to the trailing edge ( 18 ), and wherein the kink or inflection point ( 74 ) is formed such that if one follows a progression of a curve defined by the convex suction side portion ( 72 ) and the suction side addition portion ( 76 ) from the leading edge ( 16 ) up to the kink or inflection point ( 74 ), a direction of the curve changes at the kink or inflection point ( 74 ) towards an outside of the cross-section.