The invention relates to a linear, hydraulic pivot drive, especially for the flap control system of aerodynamic structures. Said pivot drive comprises a housing provided with ports for introducing a hydraulic medium, a piston which is arranged inside the housing and can be axially displaced by the effect of the hydraulic medium, and an output shaft which is provided with coarse threads and interacts with the piston in order to cover the axial displacement of the piston into a rotational movement. The invention is characterized in that the output shaft is integrated into the piston, the coarse threads running in the same direction and engaging in the piston, and the cross-section of the piston has a spline profile for effectively preventing a rotational movement of the piston.