6. Proof of Scale:
6.1: To prove that the model resembles a particular aircraft some proof of scale is required.
6.2: Proof of scale is the responsibility of the contestant.
6.3: The general outlines of the model shall approximate the full size outlines of the subject aircraft. Exact scale is not required. The model shall be judged for likeness at a distance of approximately 10 feet.
6.4: If the contestant presents no proof of scale material with the model, and the CD can determine that the aircraft is a replica of a full-size aircraft,
then the contestant will be allowed to have his/her entry considered.
6.5: Scale shall be determined by the wingspan. A change in wingspan will become a change in overall Scale. Fuselage width, height and aircraft planform or any other variations shall not exceed 10% of scale, with the exception of airfoils and size/shape of control surface within the scale outline rule.
6.6: A realistic three-dimensional human pilot and viewable instrument panel shall be appropriately installed in all Scale Aerobatic aircraft. (A one  percent flight score penalty will be assessed for noncompliance.)