I had an idea based on the simple tangential muffler to maybe drop a
few more dBs. I like the simplicity and compactness of the design
even if it's not the most effective at making a rotary quiet. Summit
and Jegs both carry an affordable selection of stainless exhaust
bends. I thought it might look kinda cool having an exhaust bend
come out the side of the cowling like a turboprop would have. If the
exit was made from a 3" bend and perforated with a drill press, it
could be fitted with a 4" outer sleeve and packed with high heat
muffler packing materials acting as a glass pack or resonator. The
muffler packing would also slightly reduce the outer sleeve
temperature protecting the cowling from high heat. If anyone is
interested I'll try to post some concept sketches. Waiting to hear
back from a guy on craigslist who is selling a 13B with transmission
so i can build a prototype.

Chad Peterson


The trouble with rotary mufflers in aircraft heavy duty service is they melt :)

This is the way to go as it is both cooled and it adds a bit of thrust like the
P51 cooling system.

http://www.rotaryeng.net/exhaust.html



Paul Lamar