Control line is a method of controlling a model aircraft. The model is connected to the pilot by a pair of lines, attached to a handle, that work the elevator of the model. This allows the model to be controlled in the pitch axis ie up and down.
The control lines are usually either stranded or solid wires of anywhere from 0.008 in (0.20 mm) to 0.021 in (0.53 mm). Fishing line may be also be used for smaller models. A third line is sometimes used to control the engine throttle, and more lines may be added to control other functions. Electrical signals sent over the wires are sometimes used in scale models to control functions such as retracting undercarriage and flaps.
General IC engines are used to power control line models but with introduction of powerful brushless motors and lipo’s some electric control line model aircraft have started to appear.
Although control line model flying is not as popular as it used to be there are still many competitions held for control line aircraft as outlined below.
Control Line Competition Classes
Speed – speed competitions are divided according to engine capacity. There is also a jet competition using pulse jet engines.
Speed models are generally launched from a “dolly” whch is left on the ground after take off.
Team Racing – team racing consists of two-person teams, a pilot and the pit crew. In team racing a number of models fly together aiming to complete a number of laps in the fastest time. A pit stop is required during the race to refuel. This is done by the pit crew. There are various classes of team racing, A and B for different engine sizes, FAI team race, Goodyear and 1/2A.
Combat – in combat competitions highly maneuverable models are flown two at a time. Each combat model tows a paper streamer, and is to opponent’s streamer as many times as possible with the propeller or wing. Points are scored for each cut and taken away when on the ground or for penalties. Combat models are fast and very agile and so often have a limited life expectancy. Accidental collisions and crashes are frequent.
Carrier – this competition is for semi-scale models of real naval aircraft. The event replicates the requirements of full-scale carrier aircraft. Takeoff and landing are from a simulated aircraft carrier deck, with arrestor wires. The pilot must take off, complete a number of fast laps, followed by a number of slow laps, followed by the carrier deck landing where the pilot attempts to snag the arrestor wire.
The score depends on the difference of the high and low speed, and the arrested landing. Carrier models generally have a third control line which allows the throttle setting of the engine to be controlled and the arrestor hook to be dropped. Some carrier models also use flaps for slower flying speeds.
Aerobatics – aerobatic competitions (sometimes known as stunt) consists of flying a fixed sequence of maneuvers which are
judged by a panel of judges for accuracy and precision. Although generally powered by IC engines, electric powered models are now making an appearance in aerobatic control line competitions.