1. Wings must have a continuous soft foam (eg. expanded polypropylene, EPP) leading edge at least 1 inches wide (measured parallel to line of flight) for the entire span of the wing.

2. At least 60% of the wing cord (from leading edge to trailing edge) must consist of continuous soft foam and/or radio equipment from the top surface to the bottom surface of the wing (excluding a soft flexible covering), at all points along the entire span of the wing.

3. The front 1 inches of fuselages or pods must consist entirely of soft foam and be of a sufficiently rounded shape to absorb impacts.

4. Fuselages must consist of at least 75% soft foam and/or radio equipment, measured in cross section, for at least half of the fuselage's length.

5. The entire model may only be covered with a soft flexible covering such as iron-on film, packing tape, fibreglass reinforced strapping tape, laminating film, or a combination of these or similar materials. Covering is deemed to be sufficiently flexible if it easily curves around the leading edge of the wing during application without first being folded, scored or pre-shaped in any way. Any glues used to attach covering must remain soft and flexible once cured and not forfeit the flexibility of the covering to which it is applied. Resin-impregnated materials are not accepted as a soft flexible covering.

6. Moveable control surfaces, fixed trailing edges, fins, winglets and tailplanes must be constructed of wood, foam, corrugated plastic (eg. Coreflute) or a combination of these materials. The moveable control surfaces can be covered in fiberglass or carbon. 

7. There are no restrictions on spar construction.

8. No electronic aids.

9. No molded stabilizers, flaps, elevators, ailerons, wing tips or fuselage parts.