ORIGINAL: 4u2nv-RCU
A year ago I bought a plane from a friend that I believed was SPA legal. It is called a Sunray and it is a Bipe tha has a stagger wing configuration with the bottom wing a gull shape. I bought the plane with a Hanno and a pipe and now realize that that is not legal. I will be danged if I am going to pull out the Hanno, it runs too sweet. I believe the option should be there for use of piped .60's. I know I am biased because of my situation but 1/2 of the nostalgia of the era is in those old screamiing motors!! I try to fly the current AMA patterns as well and can understand the desire to slow the plane to a more constant speed but to deny us the use of these motors in SPA seems to be contradictory to the spirit of the event to begin with. There is only one SPA event within a 500 mile radius of me now and I believe the more inclusive the rules the more likely for growth in contests and participation.
I have a question which also deals with tuned exhaust systems. Unless I misunderstand SPA rules, it =IS= permissible to use the quarter wave tuned exhausts that come with the Jett or Rossi motors in SPA competition, but NOT the 1/2 wave long pipes (and headers) most guys associate the "tuned pipes" which are =NOT= legal, correct?
If that is true, I dont' understand the reasoning, other than one must often tune his header to match a particular muffler and prop. But from a performance standpoint, the 1/4 wave "muffler" (tuned pipe) is really in the same performance class as the 1/2 wave pipe.
Am I correct in this understanding of the SPA rules? Anyone care to clarify/justify this reasoning?