Mailing List flyrotary@lancaironline.net Message #48591
From: George Lendich <lendich@aanet.com.au>
Subject: Re: [FlyRotary] Re: Your Muffler
Date: Fri, 9 Oct 2009 09:03:43 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
 
 Lynn,
You are reading my mind - those things you suggest is exactly as intended.
 
The cooling air holes are there to allow the air within in the cones to expand and contract without restriction.
 
I also envisage out of cowl installation or an air feed to the muffler.
 
The solid rods are also a must, to tie-in the inner tube both front and back, maybe. It would be interesting to see it done in Inconel.
George ( down under)
 Ed,
> Cones are the GO.
>
> Any bare edge will take a battering from the heat and shock waves. Cones
> formed back to back eliminate any edges.
>
> There must be supporting structure for the cones, I've used 1/4" solid
> round bar welded into the exhaust skin.
> George (down under)

Thought must be applied to the idea that eventually the structure will decompose, and then the pieces thus liberated, will plug the exit and render the engine a balance weight. As in the Mistral crash.
 
Perhaps the back to back cones could be installed over some cooling air holes in the central pipe.
A solid rod just aft of the cones could support the central pipe and help prevent such a blockage.
 
My version would have the entire muffler below the cowl in the airstream. Maybe there would be room for a collector before the muffler so as to maintain more engine power.
 
Lynn E. Hanover
 
 
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