[Tired Old Man]

I'm finishing mine up now. BME 115 and mufflers. An aquaintance had one and kept it real light. He said at the weight of his a 100cc engine was almost too much since it can only fly so fast before that big hole in front slows it down. Then again, he's so anal about weight he left the louvers off of his.

If you don't have noise issues at the fields you fly at there's no reason to use cans. They add cost, complexity, and weight. An engine with mufflers works just fine. The only place there may be an issue is at the bottom of the cowl ring where the muffler outlets may exit right at the junction of the cowl ring and the front of the fuselage. Makes for some tricky cuts in the cowl ring.