The toe brake system consist of two parts:
A moving brake pedal and a support structure. The brake pedal is connected to the original RCS pedals with hinges. A springloaded arm (drawn in magenta) protrudes from the brake pedal. This arm pushes and pulls the small lever of a sliding pot. The pot is held in place through a support structure, bolted to the RCS pedals. All parts are built from layered plywood.
Since the pot is 10 cm long, the brake arm also has to be long to provide sufficient movement at the tip. The pilots toes on the other hand are close to the hinges, so there is not much leverage. Selecting the right spring is essential: If it is too stiff, braking becomes an effort and tactile feedback is lost. If the spring is too weak, it will not pull the pot lever back to the "Up"-position.
The castors in the brake arm are taken from a music cassette and were fitted into the arm with steel nails for axles. They do a nice job of moving the potentiometer's lever smoothly between the min. and max. positions.
