This thesis addresses the development of an automatic control system to support the conversion maneuver of a convertiplane aircraft. The conversion phase represents one of the most demanding tasks for the pilot, due to the strong coupling between nacelle tilt, aircraft speed, and flight path control. In fact, during this maneuver, specific limitations – the so-called conversion corridor - exist for the nacelle angle with respect to the aircraft airspeed. The main objective of this work is to reduce the pilot workload during conversion by introducing an automatic conversion mode. In the proposed approach, the pilot activates the automatic conversion function and continues to increase/decrease the airspeed, while the system autonomously schedules the nacelle tilt angle as a function of the airspeed.