Ron;
Sport Scale you have to be the builder of the model, and you have to provide documentation for outline and color, and you get a static score from 0-100 for how closely you matched the documentation. Fun Scale you can enter a model someone else built, or it can be an ARF the documentation is less stringnet, and the static score is only 0-10 points. The flying portion is the same.
You can get the complete details in the scale rules listed on the AMA web site under the competition section.
Leroy