A radio-controlled (model) aircraft (often called RC aircraft or RC plane) is controlled remotely by a hand-held transmitter and a receiver within the craft. The receiver controls the corresponding servos that move the control surfaces based on the position of joysticks on the transmitter, which in turn affect the orientation of the plane.
Flying RC aircraft as a hobby has been growing worldwide with the advent of more efficient motors (both electric and miniature internal combustion or jet engines), lighter and more powerful batteries and less expensive radio systems. A wide variety of models and styles is available.
Scientific, government and military organizations are also utilizing RC aircraft for experiments, gathering weather readings, aerodynamic modeling and testing, and even using them as drones or spy planes
Types of kits and construction
There are various ways to construct and assemble an RC aeroplane. Various kits are available, requiring different amounts of assembly, different costs and varying levels of skill and experience.
Some kits can be mostly foam or plastic, or may be all balsa wood. Construction consists of using formers and longerons for the fuselage, and spars and ribs for the wings and tail surfaces. More robust designs often use solid sheets of wood to form these structures instead, or might employ a composite wing consisting of an expanded polystyrene core covered in a protective veneer of wood, often obechi. Such designs tend to be heavier than an equivalent sized model built using the traditional method, and would be much more likely to be found in a power model than a glider. The lightest models are suitable for indoor flight, in a windless environment. Some of these are made by bringing frames of balsa wood and carbon fiber up through water to pick up thin plastic films, similar to rainbow colored oil films. The advent of "foamies," or craft injection-molded from lightweight foam and sometimes reinforced with carbon fiber, have made indoor flight more readily accessible to hobbyists. "Crash proof" EPP (Expanded Polypropylene) foam planes are actually even bendable and usually sustain very little or no damage in the event of an accident, even after a nose dive. Some companies have developed similar material with different names, such as AeroCell or Elapor.
The late 1980s saw a range of models from the United States company US AirCore cleverly using twinwall polypropylene material. This double skinned 'Correx' or 'Coroplast' was commonly used in advertising and industry, being readily available in flat sheet form, easily printed and die cut. Models were pre-decorated and available in ARTF form requiring relatively straightforward, interlocking assembly secured with contact adhesive. The material thickness (usually 3~6mm) and corresponding density meant that models were quite weighty (upwards of 5 lb or 2 kg) and consequently had above average flying speeds. The range were powered using a clever (interchangeable) cartridge motor mount designed for the better, more powerful 0.40 cu in (6.6 cm³) glow engines. Aircore faded from the scene around the Millennium.
Coincidently this is when the material was used experimentally by Mugi - the small tough delta glider was invented. This rapidly developed into a high performance design - the Mugi Evo. Popular worldwide as the plans were immediately launched freely on the internet. Any grade or thickness of the material can be used by appropriate scaling. However the optimum material is twinwalled polypropylene sheet in 2mm thickness and at 350gsm (density)
Amateur hobbyists have more recently developed a range of new model designs utilizing the corrugated plastic or "Coroplast" material. These models are collectively called "SPADs" which stands forSimple Plastic Airplane Design. Fans of the SPAD concept tout increased durability, ease of building, and lower priced materials as opposed to balsa models, sometimes (though not always) at the expense of greater weight and crude appearance.
Flying models have to be designed according to the same principles as full-sized aircraft, and therefore their construction can be very different from most static models. RC planes often borrow construction techniques from vintage full-sized aircraft (although they rarely use metal structures).