The following is from the rec.crafts.metalworking NG, anybody have more info
One of the neatest mufflers I ever saw was made out of wood.
This was for a model airplane engine, but there's no reason to think it
wouldn't work in your application. Pick the right woods and the thing will
sound real nice...
The Mark's Models Bushwhacker had a plywood muffler and it was very quiet
for the day (this was back in the 70's and 80's.) You epoxied aluminum foil
to the inside of the wood pieces and then epoxied the whole thing together
and then glassed the outside.
I had 3 of these planes over the years (and still have one NIB :-) and on
each one of them, the muffler only lasted about 10-15 flights before the
exhaust pulses blew out the hunk of ply opposite the engine exhaust outlet.
Even when using heavier glass on subsequent mufflers (using what I learned
with the others) I would always get a blowout. This was using an OS .20
It's a great idea and really fairs the muffler into the side of the plane
which made for a very sleek little sport plane...to bad the construction
just isn't robust enough IMHO.
Actually I found this article in going through my magazine back
issues. I even found a Vol. 1 No. 1 RC Modeler from 1963! Anyway the
wood muffler article was in RCM June 1974, written by Rod and Mark
Smith (of Marks Models). It is billed as experimental, could probably
be improved with a modern hi-temp epoxy.
"Pete Christensen" wrote in
I have an old Bushwacker which uses a wooden muffler. It used plywood,
balsa, expoxy, and aluminum foil, IIRC. The mufler was made so that it
blended into the form of the fuselage. It made it look really sweet.