M9 gun director

During the late 1930s the United States Army's signal corps attempted to utilize the newly developed SCR-268 radar to provide fire control quality data to the Sperry Corporation's M4 mechanical gun director.

[1] In 1940, Vannevar Bush formed the National Defense Research Committee and its section D-2 was tasked with examining issues related to fire control headed by Warren Weaver.

He spent the next couple of weeks working with his boss to draft specifications for an analog computer that provided firing solutions for anti-aircraft guns.

[2] Later that year, Bell Labs, at the time led by Harvey Fletcher and Mervin Kelly, submitted a proposal to the National Defense Research Committee.

[7][8] In June 1944, the M9, working in concert with the SCR-584 and anti-aircraft batteries utilizing proximity fuses, formed the bulwark of defense against German V-1 flying bombs launched against southern England.

A US 90 mm anti-aircraft gun and crew during a demonstration at Bell Laboratories in 1943. The M9 gun director can be seen in the center background of the photo.