Radio control

Radio control (sometimes abbreviated R/C) is the use of radio signals to remotely control a device.  Radio control was further developed during World War II, primarily by the Germans who used it in a number of missile projects.

 Radio control systems of this era were generally electromechanical in nature, using small metal "fingers" or "reeds" with different resonant frequencies each of which would operate one of a number of different relays when a particular frequency was received.

  Radio control 'channels' were originally outputs from a reed array, in other words, a simple on-off switch.

Click image for explanation of escapement operation

This radio control airplane is carrying a scale model of X-33 and is taking part in NASA research. 

In 1904, Bat, a Windermere steam launch, was controlled using experimental radio control by its inventor, Jack Kitchen.  In 1909 the French inventor Gabet demonstrated what he called his "Torpille Radio-Automatique", a radio controlled torpedoIn 1917, Archibald Low as head of the RFC Experimental Works, was the first person to use radio control successfully on an aircraft. 

In the 1930s Britain developed the radio controlled Queen Bee, a remotely controlled unmanned Tiger Moth aircraft for a fleet's gunnery firing practice. 

The German Kriegsmarine operated FL-Boote (ferngelenkte Sprengboote) which were radio controlled motor boats filled with explosives to attack enemy shipping from 1944.  Both the British and US also developed radio control systems for similar tasks, in order to avoid the huge anti-aircraft batteries set up around German targets.  These systems were widely used until the 1960s, when the increasing use of solid state systems greatly simplified radio control.  The first general use of radio control systems in models started in the early 1950s with single-channel self-built equipment, commercial equipment came later. 

By the 1970s the trend for full-house proportional radio control was fully established.  Typical radio control systems for radio-controlled models employ pulse width modulation (PWM), pulse position modulation (PPM) and more recently spread spectrum technology, and actuate the various control surfaces using servomechanisms. 

Remote control military applications are typically not radio control in the direct sense, directly operating flight control surfaces and propulsion power settings, but instead take the form of instructions sent to a completely autonomous, computerized automatic pilot. 

Some of the most outstanding examples of remote radio control of a vehicle are the Mars Exploration Rovers such as Sojourner.  Today radio control is used in industry for such devices as overhead cranes and switchyard locomotives. 

Radio control