A new method ARNSPNS is described for the calculation of steady and time-linearized unsteady incompressible potential flow about arbitrary lifting and nonlifting bodies in an arbitrary mean steady flow field, including rotation. The method belongs to the category of the so-called panel methods. Applications have been made to wind turbines including the effects of tipvanes. A new integration scheme for obtaining the loads is applied which contains implicitly the suction force in case of a lifting surface approximation and which should improve the drag prediction in case of a full body approximation.