Anti-aircraft guns in London during the Blitz of 1940 were mostly for show. It was extremely difficult to shoot down an aircraft. The shells launched to explode in an enemy bomber’s flight path had to be timed to one-fortieth of a second, explained Future Tense fellow Jamie Holmes in a recent online event co-sponsored by Future Tense and Issues in Science and Technology.* A timing device a second off would mean an explosion 2,000 feet from its intended target.
It’s no surprise, then, that at the start of the Blitz it took about 20,000 shells to shoot down a single airplane.
Developing a solution to the problem—an electronic sensor within a shell that could detect a nearby aircraft and blow up in its proximity—was simple in theory but complicated in execution, Holmes