Given the propensity for the rotary engine to melt away
interior muffler parts ...

If I decide to go the rotary route on my Bearhawk Patrol aircraft, I know
I will waste far too much agonizing over muffler design. I hate noise!

Here in my home in extreme northern Wisconsin, I can literally sit in my
bathroom and watch snowmobiles and an occasional ATV streak by my house
about 50' from my window (A small river runs right past my house and
serves as the local snowmobile corridor). What surprises me is that these
machines are so quiet, the mufflers last for years; they take an extreme
beating in the case of ATVs. In the snowmobiles, the mufflers are totally
enclosed within a cowl that has minimum airflow, and the things all seem
to work well and last forever.

My chainsaw runs only full-throttle when it is running. I use it to cut
24" diameter trees into chunks, so it sometimes runs full throttle for
extended periods of time in hot weather, yet the mufflers function
reasonably well, never burn out, though I have never seen one glowing red
hot either.

So what is the difference between a Mazda and a Rotax snowmachine engine?

In contrast, I have struggled with exhaust-cooling on large standby
generator exhaust systems. I had to learn to tolerate seeing an engine run
with it's manifold glowing red.

Has anyone ever done the heat-dissipation calculations for a rotary's
exhaust system?
Would a marine-style water-cooled manifold require too much cooling system?

Robin

There are three variations on the rotary exhaust system.
Which variation you have will depend on how easy they are to muffle.
The 13 B normally aspirated engines have an insert in the exhaust that
breaks up the sound wave. This is the most common 13B rotary engines.
The 13B turbo rotaries had no such insert.

The RX8 has side exhaust and that is the easiest to muffle.
If you want to hear such an airplane take off and fly go to

http://www.youtube.com/watch?v=XgLw3a8DZgM

You can barely hear the engine.

Paul Lamar