I guess I am out of line here but I am going to give you my pennys worth. I am not a vintaage flier since I did not start RC flying till I was 62 and retired. I enjoy building and I like 4 stroke sound. I don't care if you want 2 strokes on the planes and fly better than me. I like the competition and fellowship and the airplanes. If you did not allow 4 stroke powered planes I would lose interest and go somewhere else since that is my preference. If a 4 stroke airplane loses to a 2 stroke in the hands of a skilled pilot so what? I would probably like Ballistic pattern but I have never seen a contest and until they started a chapter in Florida had never heard of it. More power and personnel to the BPA and to SPA. I think both organizations fill a need. Why don't you both work together and help people like me come to realize what each organization has to offer? If the planes are as fast in BPA as you seem to think then I can never fly one since I don't have the reflexes to fly jets or real fast ships. I can do some of the patterns but have a real problem judging distance since I have but one eye, so I have not competed as yet. When I learn to compensate for that problem I will join the competition in SPA and expect to win at times. Lets cooperate and make both organizations enjoyable so that newcomers want to participate in both classes. FOR WHAT ITS WORTH TO YOU. Why can you not see that the bickering that is going on is hurting both organizations and not gaining you any membership. I have followed this thread because I was getting interested in BPA but still do not seem to understand what the differences are that are so terrible betwen the two. Why cannot my Troublemaker fly in either of them with maybe an engine change out to comply with the change in rules between the two? I still don't understand why i need a pipe on the plane as I am not a plumber and could not tune one anyway.