Radio control has been around since Nikola Tesla demonstrated a remote control boat in 1893. World War II saw increased development in radio control technology. The Luftwaffe used controllable winged bombs for targeting Allied ships. During the 1950s pioneering work was done by enthusiastic amateurs to create valve based control units. Originally simple ‘on-off’ systems, these evolved to use complex systems of relays to control speed and direction. Information was encoded by varying the signal’s mark/space ratio (pulse proportional). Commercial versions of these systems quickly became available. The tuned reed system brought new sophistication, using metal reed switches to resonate with the transmitted signal and operate one of a number of different relays. In the 1960s the availability of transistor-based equipment led to the rapid development of fully proportional servo-based systems, again driven largely by amateurs but resulting in commercial products. In the 1970s, integrated circuits made the electronics small, light and cheap enough for multi-channel fully proportional control to become widely available.