F1a

F1A is a class in the Fédération Aéronautique Internationale (FAI) competition system for rubber-powered free-flight model aircraft, primarily sailplanes. The class emphasizes precision in design, construction, and operation, with the goal of maximizing the duration of a free flight under official rules. F1A is one of several free-flight categories used in international contests, including the FAI World Championships.

In F1A, models are powered solely by a wound rubber motor. No onboard electric, combustion, or other propulsion is permitted. Flights are initiated by hand from a fixed launch peg, and the aircraft is flown without any further control once released. The key performance metric is the time the model remains aloft from launch to landing; organizers may schedule multiple rounds, and the longest valid flight often counts toward a competitor’s result.

Design and construction focus on efficiency, stability, and light weight. Typical F1A airframes use long, high-aspect-ratio wings and slender fuselages made from balsa, plywood, or lightweight composites. The tail surfaces are sized to ensure stable, efficient gliding. A carefully wound rubber motor, proper balance, and precise center of gravity are critical, with pilots tuning airfoil selection, wing loading, and overall aerodynamics to maximize time aloft.

History and status: F1A emerged in the mid-20th century as part of organized free-flight competition and remains popular among hobbyists and competitors worldwide. It continues to be a core class in international events, alongside other F1 categories such as F1B and F1C.