Mailing List flyrotary@lancaironline.net Message #51661
From: Mike Wills <rv-4mike@cox.net>
Subject: Re: [FlyRotary] Re: Mufflers
Date: Fri, 9 Jul 2010 19:35:14 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
I may not be Mr. Muffler, but I have a copy of the spiral flow on my 13B powered RV-4 too. Home made from Inconel, it is holding up OK but doesn’t muffle worth a damn. A friend has a Cobra kit car with spiral flow sidepipes on a more or less stock 302. They don’t work worth a damn either.
 
After Mark switched to the DNA muffler and reported positive results I switched too. The DNA was no quieter but cost me some power. So I switched back. Still looking for the right muffler solution that will fit in my extremely space limited application without costing too much power. In my opinion this is the biggest downside with my rotary install.
 
Mike Wills

Sent: Friday, July 09, 2010 2:44 PM
Subject: [FlyRotary] Re: Mufflers

Steve, 

Yes, that would be me, "Mr. Muffler" himself.  The Moroso style muffler didn't muffle very well and it kept melting the bolt holding the baffle in place.  I finally went with a SS bolt which didn't melt.  In an effort to find something that wasn't as noisy, I discarded it for the DNA muffler which wasn't much quieter, but it survived the harsh rotary environment better than anything else I had tried up to that point.  I'm now running an inconel 625 tangential muffler, which is the best as for noise attenuation I've used to date.  The only problem is that I suspect I'm losing hp due to excess back pressure.  But at leaast I can hear to talk on the radio.  Its my opinion at this stage of the game that the best muffler is a turbo.  At least you achieve a fairly quiet exhaust note, and get some extra hp too.

Mark S.

On Fri, Jul 9, 2010 at 8:15 AM, Stephen Thomas <glasair2@me.com> wrote:
I remember some discussion a while back regarding the concept of the Moroso spin muffler.  See:

http://moroso.com/catalog/categorydisplay.asp?CatCode=35054

Anyone out there still using it?  What were the conclusions of those who tried it?  I know someone made one from scratch.  I have a small Burns Stainless muffler that is totally inadequate in terms of sound attenuation.  So, I'm looking for alternatives and remember a lot of discussion regarding this device.


Steve Thomas
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