The invention relates to a rotor blade (20), especially for a rotary wing aircraft. The invention is characterized in that an aerodynamically effective rotor blade profile with a profile nose region (21), a profile base body (20a) with a profile core, an upper and lower cover skin (30) that envelops the profile core (22), and a profile rear edge region (23) with a rear edge (40) and a reversibly bendable supporting member (26) that can be attached with the first end to the end region of the profile base body (20a) pointing toward the rear edge (40) and projects with the second end freely out of the profile base body (20a) and its end region toward the rear edge (40) and forms a movable rotor blade flap (24), and several actuators (35) that are dynamically connected to the projecting second end of the reversibly bendable supporting member (26) and an arc-shaped flap deflection can be initiated via the change in length of the actuators, the second end of the reversibly bendable supporting member (26) that forms the rotor blade flap (24) viewed in the direction of the span (S) being divided by notches (34) into several segments to which at least one actuator (35) at a time is assigned.