A radio controlled toy (or RC toy) is a toy that is steerable with the use of radio control. All types of vehicles imaginable have had RC systems installed in them, including cars, boats, planes, and even helicopters and scale railway locomotives. RC electronics have three essential elements. The transmitter is the controller. Transmitters have control sticks, triggers, switches, and dials at the user's finger tips. The receiver is mounted in the model. It receives and processes the signal from the transmitter, translating it into signals that are sent to the servos. The number of servos in a model determines the number of channels the radio must provide. Typically the transmitter multiplexes all the channels into a single pulse position modulation radio signal. The receiver demodulates and demultiplexes the signal and translates it to the special kind of pulse width modulation used by standard RC servos.
There are thousands of RC vehicles available. Most are toys suitable for children. What separates toy grade RC from hobby grade RC is the modular characteristic of the standard RC equipment. RC toys generally have simplified circuits, often with the receiver and servos incorporated into one circuit. It's almost impossible to take that particular toy circuit and transplant it into other RCs.
Hobby grade RC systems have modular designs. Many cars, boats, and aircraft can accept equipment from different manufacturers, so it is possible to take RC equipment from a car and install it into a boat, for example. However, moving the receiver component between aircraft and surface vehicles is illegal in most countries as radio frequency laws allocate separate bands for air and surface models. This is done for safety reasons. Most manufacturers now offer frequency modules that simply plug into the back of their transmitters, allowing one to change frequencies, and even bands, at will. Some of these modules are capable of synthesizing many different channels within their assigned band.
Hobby grade models can be fine tuned, unlike most toy grade models. For example, cars often allow toe in, camber and caster angle adjustments, just like their real life counterparts. All modern computer radios allow each function to be adjusted over several parameters for ease in setup and adjustment of the model. Many of these transmitters are capable of mixing several functions at once, which is required for some models.
In the 1980s, a Japanese electronics company, Futaba, copied wheeled steering for RC cars. It was originally developed by Orbit for a transmitter specially designed for Associated cars It has been widely accepted along with a trigger control for throttle. Often configured for right hand users, the transmitter looks like a pistol with a wheel attached on its right side. Pulling the trigger would accelerate the car forward, while pushing it would either stop the car or cause it to go into reverse. Some models are available in left handed versions.
Internal combustion engines for remote control models have typically been two stroke engines that run on specially blended fuel. Engine sizes are typically given in cm or cubic inches, ranging from tiny engines like these .02 cubic inches to huge 1.60 cubic inches or larger. For even larger sizes, many modelers turn to four stroke or gasoline engines. Glow plug engines have an ignition device that possesses a platinum wire coil in the glow plug, that catalytically glows in the presence of the methanol in glow engine fuel, providing the combustion source.
Electric power is often the chosen form of power for aircraft, cars and boats. Electric power in aircraft in particular has become popular recently, mainly due to the popularity of park flyers and the development of technologies like brush less motors and lithium polymer batteries. These allow electric motors to produce much more power rivaling that of fuel powered engines. It is also relatively simple to increase the torque of an electric motor at the expense of speed, while it is much less common to do so with a fuel engine, perhaps due to its roughness. This permits a more efficient larger diameter propeller to be used which provides more thrust at lower air speeds.