History of RC
Radio control (RC), as defined by Webster’s New Millennium Dictionary of English, is the use of radio signals to remotely direct a device. In our hobby, the “device” is an unmanned aircraft. The radio signals are being sent from a “radio”, otherwise know as a transmitter. The transmitter is being operated by a ground based pilot who is in close proximity to, but not in the aircraft. The decoder, also known as a receiver, in the aircraft receives the radio signals and converts those signals into commands that are sent to the various portions of the aircraft that control its direction of flight. Although this is a very simplified description of what actually occurs, we now know the basics of “Radio Controlled Flight” and we can move on to where it all began…
Nikola Tesla, an inventor and mechanical and electrical engineer, is often described as the most important scientist and inventor of the modern age. Tesla’s work is the basis for modern alternating current electrical systems, such as you would find in your home or office. He was also given credit for inventing the radio by the United States Supreme Court in 1943.
Of great importance to us was an invention that he debuted at an exhibition in Madison Square Gardens in 1898. Tesla demonstrated a model boat that would apparently obey commands from the audience. It was, in fact, controlled by Tesla who was listening to the verbal requests, then sending the appropriate frequency to tuned circuits in the boat which would, in turn, cause the boat to move in the desired direction. He was granted a U.S. patent for this invention on November 8th, 1898. And so began radio control!
Nikola Tesla
Although there have been various patents given to various inventors and engineers since Tesla’s time, for our purposes, the next step in the evolution of radio controlled flight took place in 1917 when Archibald Low became the first person to successfully fly a radio controlled aircraft. Archibald Low was an English inventor, consulting engineer, and research physicist. He has been called the “father of radio guidance systems” because of the advances he pioneered on guided rockets, airplanes and torpedoes.
Archibald Low
In the 1930’s, Britain developed a remotely controlled unmanned de Havilland Tiger Moth for use in a fleet’s gunnery firing practice. This aircraft was superseded by a higher performance model purpose built for target practice. Although radio control was used by the military forces of many countries for various applications, the first general use of radio control took place in the early part of the 1950’s.
General public use of radio control began with self-built, single-channel equipment. Initially, the control surfaces were operated by an electromagnetic escapement. These used the stored energy in a rubber-band loop to provide simple on-off control. The primary control was provided by a rudder which had three positions; right, neutral and left. The electromagnetic escapements were also occasionally used to control other functions, such as motor speed.
With the invention of crystal-controlled superheterodyne receivers we found that the equipment was more versatile and available at a lower cost. Multi-channel development made the operation of aircraft considerably easier as aircraft typically required at least three channels (yaw, pitch and motor speed) as opposed to ground based vehicles which only needed one or two.
The early radio control systems used amplitude modulation (AM), required an amateur radio operator’s license and only allowed the control of two or three channels. Along came frequency modulation (FM) which allows the use of 20 or more channels, but suffers from interference issues. Pulse-code modulation (PCM) was next in line and uses a computerized digital-bit stream to communicate with the aircraft. PCM, although superior to FM, is also prone to interference and loss of communication with the aircraft.
The technology in use today varies. The most common tend to be FM, PCM and the most current, 2.4 gigahertz. The 2.4 gigahertz band is capable of more secure communication with the aircraft as well as an increasing resistance to interference and jamming. You may see this bandwidth referred to as Spread Spectrum. You may already be familiar with Spread Spectrum as it is a vital component of many of the telephone systems in use today.
Beginning with Nikola Tesla and his RC boat, spanning over 100 years and incorporating amplitude modulation (AM), frequency modulation (FM), pulse-code modulation (PCM) and the most modern 2.4 gigahertz technology, we can see that radio control has come a long way. With the modern market place making radio control more affordable than ever before, more people of all ages are becoming interested in this wonderful hobby. Whether you enjoy aircraft big, or aircraft small, a GREAT time can be had by all!
radio control. Dictionary.com. Webster’s New Millennium™ Dictionary of English, Preview Edition (v 0.9.7). Dictionary.com, LLC. http://dictionary.reference.com/browse/radio control (accessed: April 01, 2009).
This article is licensed under the GNU Free Documentation License. It uses material from the following Wikipedia articles:
http://en.wikipedia.org/wiki/Radio_control