# World War II Anti-Aircraft Gun Documentary "Ack Ack" 77954

This WWII Ministry of Information film shows the Ack Ack gun crew using their mobile gun. The narrator speaks about the diverse backgrounds of the recruits, and discusses how the gun (most likely a 40mm Bofors cannon) can fire a shell up to 30,000 feet. A height finder and a predictor are used to come up with a firing solution to hit incoming aircraft. The commentator also notes that enemy planes often fly a zig-zag or other evasive course to avoid being hit, but this can also have a positive outcome in that it prevents bombers from making accurate attacks. A command post is seen at the 3:30 mark, with enemy and friendly planes being tracked at all times. As nighttime approaches, radar is also used to spot enemy aircraft. The Kerrison Predictor was one of the first fully automated anti-aircraft fire-control systems. The predictor could aim a gun at an aircraft based on simple inputs like the observed speed and the angle to the target. Such devices had been used on ships for gunnery control for some time, and versions such as the Vickers Predictor were available for larger anti-aircraft guns intended to be used against high-altitude bombers, but the Kerrison's electromechanical analog computer was the first to be fast enough to be used in the demanding high-speed low-altitude role, which involved very short engagement times and high angular rates. Anti-aircraft warfare or counter-air defence is defined by NATO as "all measures designed to nullify or reduce the effectiveness…

- Kind: Documentary
- Genres: War, Documentary, Industrial and advertising
- Archive: [Internet Archive](https://archive.org/details/77954AckAck)
- Licence or status: none stated by the archive
- Who can watch: Teens profiles and older (the archive gives no rating; placed by Invisible Network from its collection and subjects)

[Watch now](https://invisiblenetwork.ai/watch/archive/ia/77954AckAck?play=1)