RE: WACO YMF
Bob,
You didn't interupt, you asked a legit question. A Jungmann is a radial bi-plane, same as the Waco. Probably the reason you didn’t get a response is nobody has any experience with a .61 engine in a Waco. One of the 1/6th Wacos has a ST 75 for power. Most of the 1/5 scale Wacos have at least a 120 Four Stoke engine. Bill likes the OS Twin 160 for power, but is now planning for a gas engine. I looked at Keleo, Slimline and a couple of other companies. You best bet is probably the Slimline Pitts muffler if you are mounting the engine inverted.