Diagram of a Sperry bomb-sight O-1 used by the United States Army Air Forces (USAAF) bombers in World War Two. By manipulating the various control knobs, the skilled bombardier not only brings the aiming mechanism into operation, but actually takes feeds the necessary data into the "mechanical brain" which makes allowances for such factors as altitude, speed, wind-resistance and drift, than computes them into an answer which automatically aims and releases the bombs accurately.