The Ruhrstall X-4 [1] had five and a half kilometers of wire 80 years ago, along with a 20kg warhead and an acoustic proximity fuse. 1: Never deployed operatio

The Ruhrstall X-4 [1] had five and a half kilometers of wire 80 years ago, along with a 20kg warhead and an acoustic proximity fuse. 1: Never deployed operationally Luftwaffe wunderwaffen, first tested in August 1944, wire-guided air-to-air missile.