Raytown Amateur Radio Club
Technology Net - Radio Controlled Model Airplanes
by Roger Snowdall - WØKWJ
Technology Net - Friday - August 7, 2009 8:00 PM - KØGQ repeater 145.170(-) Echolink - KØGQ-R - Node# 403841
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In 1917, the first radio controlled airplane was very basic, but successful. During World War II, Germany tried a variety of weapons that were operated by radio control. Radio controlled model airplanes have evolved over the years and seen improvements since that first flight in 1917. In 1929, the "Model Airplane News" magazine began. It is still popular today with radio control hobbiests.
During the 1950s, remote control models became popular but they had to be recharged frequently. Planes were free flight rubber band powered pre-set control surfaces. The early radio controls were super regen, single signal, tone modulated. Also multi-channel using reeds in the receiver, detecting tones from the transmitter. Radios went from super regen to super heterodyne, single and double conversion. Range was well over a mile. Typical systems had four channels for control. Elevation, ailerons, rudder and throttle (See graphic below). Digital proportional systems also came out in the 50's having positive positioning of servos at all times.
Model Airplane motor types are: Rubber Band (not used much anymore). Fuel engines, 2 and 4 cycle. Electric motors, using NiCd, NiMH and Lithium batteries.
Types of modulation used in a Radio Control transmitter is AM and FM. The RF carrier uses time division multiplier running at various sample rates.
Model Airplane Radio Frequencies: 72 MHz - 50 channels 10 kc spacing, 50 MHZ - 10 channels (6 meter Ham Band), 27 MHz - 5 channels (CB - 11 meters).
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