I think if there was a class people would come. Why build one if you are not allowed to compete with it? It seems this topic is beat to death here, and passionate feelings on both sides. Since there is so much interest, I think if there was a "Ballistic" class, you would see more of those planes built, maybe re-kitted as well. There is no reason not to try for another class IMHO. One thing I am not 100% clear on is the noise of a piped .60. I am building an older pattern kit, and went old school with a Rossi .61 and pipe, Spring air 3-gear retreacts. (Have not runt he engine as of yet). Have you been to the field when the 3-D guys are flying a 33% Edge with a DA-500 or something like that up front? That is loud, and I can hear them at my house when they fly. Yes I am lucky enough to live 1 mile away from a paved runway field. Actually our club had a story on it an issue or so ago in the AMA magazine. Fox Valley Aero club.
So how loud is a piped .60 vs. a 1/3 scale monster?
They are loud, but the muffled tuned pipes are probably quiter than the IMAC, but at a higher frequency. The prop is probably as loud as the engine with the muffled pipes. At most of the SPA sites I doubt noise is not a problem. It wasn't till recently at the Hotlanta meets in Paulding Co GA. Many are held in small towns in AL, GA, and TN. If you look at the SPA site I doubt there are more than 20 competitors at most meets. Maybe more will join and the meets will get bigger, and more of them.