Tabs of this kind are called spring tabs

The final step (Figs 9.17 and 9.18, overleaf) required a little mechanical inge­nuity, but otherwise it was a natural development. The pilot was given the means of adjusting the bias while in the air, and thus he was enabled to correct any flying faults, or out-of-balance effects, as and when they occurred.

On small aircraft with manual controls these tabs may be fitted to all of the primary control surfaces. The pilot can adjust their settings from within the cockpit and can thereby arrange the trim so that the aircraft will fly ‘hands- off’ in almost any flight conditions. On aircraft with power-operated controls, such tabs are unnecessary and the trim wheels are simply used to reset the neutral or hands-off position of either the control column or the actuator system. From the pilot’s point of view this feels almost exactly like setting a trim tab.

Rigid link adjustable on ground

Evolution of control tabs