Information on the 2025 F4 Team Trials (for 2026 F4 World Championships) is now available at https://nasascale.org/
Scroll down on the main page to the official Team Selection Program document.

While the F4B rules are similar to AMA 509 Sport Scale, there is no "builder of the model" rule, so you can fly an ARF or someone else's model.  PM if you are interested and want to discuss F4B.

No builder of the model rule?

Dick - no builder of the model rule in F4B and F4H.  In static, there is a category called "Originality of Model" (K=6) where you would lose some points if you enter an ARF or a model built by someone else.  Yes, there were some at the 2024 WCs in F4H.