What happens to the aircraft's CL max when Fowler flaps are deployed at low angles?

When Fowler flaps are deployed, especially at low angles, the aircraft's maximum coefficient of lift (CL max) increases. This occurs due to several aerodynamic factors. One primary reason for this increase is that Fowler flaps not only extend outwards but also rotate downwards, which effectively enlarges the wing's surface area.

As the flap is extended, it alters the shape of the airfoil, allowing for smoother airflow over the wing and delaying airflow separation. This enhancement in the airflow results in a higher maximum lift potential at lower angles of attack, which is crucial during takeoff and landing phases where maximum lift is often required.

The increase in the wing area also plays a critical role, as a larger wing area can support a greater amount of lift. Therefore, when Fowler flaps are deployed, they permit the aircraft to achieve a higher CL max, making it a beneficial feature in aircraft design for improving performance during critical phases of flight.