I guess I don't understand the problem, or why everybody just immediately tosses the muffler. In just about every experiment I have tried with these sorts of smallish schneurle engines, they ran better, or even much better, with the stock muffler. It's the key to the 20FP run, for example. It runs very poorly with a tongue muffler or open exhaust. A few ounces is never worth even a slight reduction in the run quality.
I have no idea if this is the case for this new engine, maybe it would work better with a different muffler, or maybe (like all the others I tried) it would screw it up. But for goodness sake, don't let this sort of "fencepost wisdom" folklore overly effect the results. It would be a real shame if manufacturers started putting out engines that ran more poorly and more noisily than they should just because someone has it in their heads that it can't possibly be right without ever having tried it.
Brett
Well the reason I ask is that most of the "old standard" 15 size planes are overwhelmed by the weight of the standard 15 sized engines--even before you add a muffler. Add the muffler (and I recommend some type of muffling with a 15 sized engine) and now you need a lot of tailweight.
You don't see this problem with the 20-25 sized engines, because (usually) they seem to be going into "old standard" 35 sized plane, so even if they end up a little heavier than a Fox 35, you won't need to add a lot of extra tailweight (if any).
For me that is the issue. I've used 10 sized engines on the 15 size planes, simply for balance and weight reasons--- and in additionthey have plenty of power too. I've also used a Fox15BB (a heavy 15) with stock muffler on a FliteStreak Arf.
So as a comment, the real issue I guess, is that the "Jr" planes, typically are on the small size for a modern 15 size engine. Maybe we need some new designs which fit the power you get from a modern powerplant.
Topic: B-15, A New Offering From Brodak (Read 3711 times)