I built a plane in the early 90's with wingtip smoke. It had an 85" wing and powered by a quadra 52. The wing was foam and I cut a hole down the length of it and made a tube of Nomex paper in it. The exhaust system was Rube Golberg to get it in the fuse and than routed to aluminium tubes that were in the wing. With all that tubing the engine was down a bit on power also. There was an article in RCM in about 91 or 92 that a club member did on it