Paul,
 Can anyone tell me the temp that the exhaust will reach on a
rotary at full noise, or what temp the muffler will have to handle?
Neil.


About as high as 1800 F at full chat.
Furthermore the pulse frequency is as high as 14,000 pulses per
minute or
233 pulses per second. This is very destructive exhaust system and
mufflers.
Lots of energy in the exhaust. It is why the rotary makes a good
turbo compound engine.

The solution is make them out of .065" 321 SS.
If money is no object make them out of .049" Inconel.
The best thing is to put nothing inside. Inside parts have been known
to melt and block the exhaust causing a crash. If there is nothing
inside that can not happen. Most of the external parts will be
cooled by air convection and or radiation. It is possible to put a
cooling tube in the center of a tangential muffler and pass cooling
air through it. Make it at least .065 thick if 321 SS.

Square or rectangular pipes are better than round.

Here are some configuration that do not use internal parts.


Paul Lamar

At this past weekends EAA meeting at Whiteman airport our quest speaker
spoke to us about powder coatings and things related. One coating he
told us about is a non carbon ceramic coating used to prevent metals
from oxidizing.
  Normally stainless blues from heat. This he said was due to oxygen
transfer in the metal. This new coating prevents oxides from interacting
on the metal surface, keeping it from corroding, preventing stainless
from blueing.
 The German company who makes it applies it to a thickness of about 8
'atoms' thick, (or so he said). It is a new material and may not be
widely available yet. If anyone knows more detail about the inventor and
this invention, it would be useful for our purposes.

Ed Carver