The Flettner-type servo tabs on the C.570 were designed to enhance the aircraft's control and stability. These tabs are small control surfaces attached to the main control surfaces (like ailerons or rudders) that move in the opposite direction to the main surface. This movement creates a differential aerodynamic force that assists in controlling the aircraft, making it easier for the pilot to maneuver.

Specifically, the purpose of these servo tabs included:

1. Reducing Control Forces: By providing additional aerodynamic assistance, the Flettner tabs reduced the amount of force required by the pilot to move the control surfaces, making the aircraft easier to handle, especially at high speeds.

2. Improving Stability: The tabs helped maintain stability during flight by providing a more responsive control system. This was particularly beneficial in turbulent conditions or during maneuvers that required quick adjustments.

3. Enhancing Control Authority: The use of servo tabs allowed for better control authority at lower speeds, which is crucial for takeoff and landing phases of flight.

Overall, the incorporation of Flettner-type servo tabs in the C.570 contributed to improved flight characteristics, making the aircraft more user-friendly and enhancing its performance.