Controlline

ControlLine is a form of radio-controlled model aircraft sport where pilots operate aircraft at a fixed distance from themselves, typically maintaining a circular flight path around a central point. Unlike free-flight models, ControlLine planes are powered by small internal combustion or electric motors and are controlled via a control line tether, which connects the aircraft to the operator.

The control line system employs two to four wires that transmit commands from the pilot’s hand-held transmitter or handle to the aircraft's control surfaces. The pilot manipulates the handle, which changes tension on the wires and thus adjusts the aircraft’s elevators, ailerons, or rudder, enabling precise maneuvering. This system allows for immediate control responses and facilitates various flight maneuvers, including loops, rolls, and figure eights.

ControlLine models vary from simple trainers suitable for beginners to advanced competitive aircraft designed for high-speed and aerobatic performances. The sport originated in the early 20th century and gained popularity as a recreational activity and competitive discipline, especially during the mid-20th century.

Safety considerations are important in ControlLine flying due to the tethered nature of the aircraft and the high speeds involved. Participants typically fly in designated areas with appropriate barriers to protect spectators and operators.

ControlLine remains a niche but enduring hobby within the broader radio-controlled aircraft community, valued for its direct tactile connection between pilot and aircraft, as well as its emphasis on precision and skill in maneuvering tethered models. It continues to be supported by clubs and organizations worldwide that promote practice, competition, and technological innovation in the field.