Buddy Box

Buddy boxing, often referred to simply as the “buddy box” system, is a widely used method of training novice pilots in the operation of radio-controlled (RC) aircraft. The system enables a student and an instructor to operate two transmitters that are electronically linked, allowing the instructor to retain overall command of the aircraft while providing the student with controlled opportunities to fly. This approach has become standard practice among major RC radio manufacturers and is considered an essential safety and instructional tool in aeromodelling.

Technical Framework and Compatibility

Buddy boxing is made possible by connecting the instructor’s transmitter (the master) to the student’s transmitter (the student unit) via a dedicated umbilical cable. This cable allows signal sharing between the two devices. Although the six major manufacturers—Spektrum RC, Futaba, Japan Remote Control, Hitec, Sanwa Electronic, and KO Propo—support buddy boxing functionality, two incompatible types of DIN connectors are commonly used. As a result, both transmitters must feature the same connector type for successful linkage, even though the radios themselves may be of different brands.
Because the master transmitter controls the aircraft, both units must have identical servo reversing settings and trim configurations. These adjustments ensure that the control signals from either transmitter correspond correctly to the aircraft’s control surfaces and prevent unintended or hazardous inputs.

Operational Method

The primary mechanism of the buddy box system is a long-handled spring-loaded switch located on the master transmitter, usually in the top left corner. The instructor holds this switch and activates the student’s control authority by pulling it forward. When held in position, flight control is transferred to the student transmitter. Releasing the switch immediately restores command to the instructor, allowing rapid intervention in the event of student error or loss of orientation.
Variations exist across older transmitters, such as the Futaba 6XA, where the trainer control is implemented as a pushbutton rather than a toggle switch. In such models, the toggle is reserved for auxiliary functions, such as operating retractable landing gear on channel five.
Notably, the master and student transmitters do not need to operate on the same radio frequency. Because the master transmitter alone communicates with the aircraft’s receiver, the student transmitter effectively becomes a passive control interface. It remains switched off throughout operation, drawing its power from the master unit via the connecting cable. Despite being switched off, the student transmitter’s electronics activate when connected, enabling full control input capability without transmitting radio signals.

Training Application and Safety Considerations

Buddy boxing is recognised as a highly effective method for RC pilot instruction. Novices experience real-time flight control while benefiting from immediate instructor intervention when necessary. This reduces the risk of aircraft loss or damage and promotes faster skill acquisition. By isolating command responsibility to the instructor unless intentionally delegated, the system provides a safe environment for practising take-offs, manoeuvres, landings, and recovery from potentially hazardous situations.