Inflating a fighter-pilot's anti-G suit to the correct pressure is facilitated by the pressure regulator design. Using Preview Control, the movement of the control stick is used to predict what the G-force on the aircraft will be in the time ahead. A computer determines what pressure is needed in the suit to safeguard the pilot at that G-force. The size of the air-flow aperture in the regulator is defined by overlapping windows in the housing and rotor of the regulator. The rotor is moved to give the correct overlap by means of a servo motor or stepper motor, which positions the rotor in response to the computer output. The very fast, stable, response of the regulator to the computer input enables the suit pressure to follow the G-forces predicted by Preview Control with great accuracy.