What is the purpose of a spring tab?

The purpose of a spring tab is indeed to aid control movement at high speeds. When an aircraft is flying at high velocities, the aerodynamic forces acting on control surfaces, such as ailerons or rudders, increase significantly. This can make it more difficult for pilots to make fine adjustments to these controls due to the higher pressures involved.

Spring tabs are designed to assist in this process by providing a mechanical advantage that effectively reduces the amount of force required to move the control surfaces. They work by using a spring mechanism that counteracts the aerodynamic loads, allowing for smoother and more responsive control inputs, which is particularly crucial during high-speed flight when rapid maneuvers may be necessary.

The other options do not accurately represent the primary function of spring tabs. For instance, while increasing drag during landing or improving fuel efficiency are important considerations in aircraft design, those functions are not the intent of a spring tab. Additionally, weight distribution is a separate consideration that pertains more to overall aircraft design and load management rather than the specific role of spring tabs in control surface movement.