Mailing List Message #65327
From: Neil Unger <>
Subject: Re: [FlyRotary] Re: Exhaust setups
Date: Tue, 12 Nov 2019 08:29:51 +1100
To: Rotary motors in aircraft <>

Gun suppressors are simply a tube with multiple baffles in it with the center holes just bigger than the projectile.  Then remember there is only one shot to silence at a time.   Again I am guessing, but it seems that the stock exhaust header does silence the noise some what as well.  I know of a set up that uses the stock manifold into a muffler and is does a great job in noise elimination.  The manifold I am cutting down weighs almost  10 pounds, (with the end cut off). so while this weight is significant, it i appears to be good "value"

Mat, no consolation, but I also have a perforated tube sitting in my shed destined to be the final "quietener" on my setup,  (aka Paul Lamar) but you have saved me the trouble as it obviously does not work.  It would appear that a muffler made of inconel with internal baffles like a rifle silencer may be simplest.  Baffles made like multi blade impellers to swirl the exhaust as apparently "rubbing" the gas will help quieten the noise.

Heat in exhaust.  Mat I spent years worrying to death about take off heat at 1800 degrees as I had an exhaust gas temp sender.  My mate had no such probe and flew for years in bliss as to exhaust gas temps.  When he finally pulled his engine down, it was perfect as to any damage due to hot EGT.  This however, is a worry for a turbo.  Supercharger eliminates this worry, but I need the "muffler" effect like we all do.  All compromises as usual.


On 11/12/2019 7:28 AM, Thomas Mann wrote:
I would really like to hear from someone like a gunsmith who has experience in the design and construction of suppressors.
They typically devoid of any packing to collapse/blow out.
As I recall, Al Geitzen had a similar setup on his 3-rotor.
T Mann
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