This question has come up several times. I type at a snails' pace so forgive me if I sound short. The idea is simply rubbish. The rotary may have a similar exhaust sound with the two stroke but that is where the similarity ends.
If you want the definitive story on the subject, get a copy of "Two-Stroke Tuner's Handbook" by Gordon Jennings. Very interesting but of little use to the rotary enthusiast other than to educate one about how little it applies to our engine of choice.
----- Original Message -----
From: kevin lane
Sent: Tuesday, March 02, 2004 11:53 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] muffler questions
it has struck me that the rotary engine is quite similar to the 2 cycle as far as exhaust noise. since some 2 cycle engines use resonators I wondered why this approach isn't also used. last week dr. chuck Williams spoke at the chapter 782 meeting, a life-time expert on 2 cycles. I couldn't get him to expound too much about exhaust, but found it interesting that he suggested a muffler with a rotor inside, just like a turbo, althought performing no work other than dampening the sound pulses. has this approach ever been tried? maybe that old joke about muffler bearings was true! since he was mostly experienced with racing snowmobiles, he said they simply use very long exhaust pipes for noise suppression, although not a big concern in the racing circuit. I have tried looking up info on resonator design, but haven't come across anything yet.