A radio controlled plane (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 planes 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 planes for experiments, gathering weather readings, aerodynamic modeling and testing, and even using them as drones or spy planes.There are many types of radio controlled planes. For beginning hobbyists, there are park flyers and trainers. For more advanced pilots there are glow plug engine, electric powered and sailplanes. For expert flyers, jets, pylon racers, helicopters, autogyros, 3D planes, and other high end competition planes provide adequate challenge. Some models are made to look and operate like a bird instead. Replicating historic and little known types and makes of full size planes as flying scale models, which are also possible with control line and free flight types of model planes, actually reach their maximum realism and behavior when built for radio control flying.Gliders are planes that do not typically have any type of propulsion, as a general rule. Because most gliders are unpowered, flight must be sustained through exploitation of the natural lift produced from thermals or wind hitting a slope. Dynamic soaring is another popular way of providing energy to gliders that is becoming more and more common.Jets tend to be very expensive and commonly use a micro turbine or ducted fan to power them. Most airframes are constructed from fiber glass and carbon fiber. Inside the aircraft, wooden spars reinforce the body to make a rigid airframe . They also have kevlar fuel tanks for the Jet A fuel that they run on. Most micro turbines start with propane, burn for a few seconds before introducing the jet fuel by solenoid. These aircraft can often reach speeds in excess of 320 km/h (200 mph). They require incredibly quick reflexes and very expensive equipment, so are usually reserved for the expert.Some radio controlled planes are built to replicate full scale planes designs from aviation history, for testing of future aviation designs, or even to realize never built proposed planes, is that of radio control scale aeromodeling. Various scale sizes of RC scale planes have been built in the decades since modern digital proportional, miniaturized RC gear came on the market in the 1960s, and everything from indoor flyable electric powered RC Scale models, to enormous giant scale RC Scale models, in scale size ranges that usually run from 20% to 25%, and upwards to 30 to 50% size of some smaller full scale aircraft designs, that can amazingly replicate some of the actual flight characteristics of the full scale planes they are based on, have been enjoyed, and continue to be built and flown, in sanctioned competition and for personal pleasure, as part of the RC scale aeromodeling hobby.Since about 2004, new, more sophisticated toy RC planes, helicopters, and ornithopters have been appearing on toy store shelves. As of 2012, the toy class RC plane typically has no elevator control. This is to manage costs, but it also allows for simplicity of control by unsophisticated users of all ages. The down side of lack of elevator control is a tendency for the airplane to phugoid. To damp the phugoid oscillation naturally, the planes are designed with high drag which reduces flight performance and flying time. The lack of elevator control also prevents the ability to pull back during turns to prevent altitude loss and speed increase. Costs range from 20 to 40 USD. Crashes are common and inconsequential. Throttle control and turning reversal (when flying toward the pilot) rapidly become second-nature, giving a significant advantage when learning to fly a more costly hobby class RC planes.