RC helicopters, also known as radio-controlled helicopters, are model aircrafts that come in varying styles and designs. Some designs benefit from greater maneuverability but suffer from reduced aerobatic control. They are flown by remote controls operated by the user. These controls are affected by small servo motors located in specific areas of the helicopter.

Construction
RC helicopters are made of plastic, glass-reinforced plastic, carbon fiber or aluminum. The blades are made from carbon fiber, wood or fiberglass. They are typically constructed by the user from a kit. This process can take anywhere from 5 to 20 hours to complete. The kits contain moving parts that any full-size helicopters feature, from the rotor blades to the swashplate.
Function
RC helicopters are most commonly used by hobbyists for recreation and entertainment. They may also be used for aerial photography, filming, remote inspection or policing. RC helicopters made specifically for these purposes are produced by specialized manufacturers.
Types
There are three types of RC helicopters available to consumers. The first,nitro helicopters, are the most popular and come in sizes of 15, 30, 50, 60 and 90. These numbers indicate the size of the nitro motor used in the helicopter. Size 15, for example, has a 0.15 cubic-inch motor. The flight time for these types of RC helicopters is 7 to 14 minutes.

Electric RC helicopters were recently developed and are gaining in popularity.They are powered by Lithium Polymer batteries and have a flight time of 4 to 12 minutes. Gas turbine or gasoline RC helicopters are the third type. They are the most expensive and least popular due to the high cost.

Competition
Competition, also known as aerobatic, RC helicopter flying, is subject to rules created by the Federation Aeronautique Internationale. Included in these rules are predetermined routines for aerobatic and hovering. 3D is another form of competition RC helicopter flying. This type of flying features advanced aerobatics, sometimes in freestyle form. There may also be predetermined moves created by the competition organizers. Two of the most well-known 3D RC helicopter competitions include the United States' Extreme Flight Championship (XFC) and the United Kingdom's 3D Masters.
Controls
RC helicopters have at least four controls. Left/Right cyclic causes the helicopter to roll. Fore/Aft cyclic affects the airspeed. Left/Right yaw causes the helicopter to angle right or left. Collective pitch/Throttle causes the helicopter to climb or dive.

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