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Date: Sun, 06 Dec 2009 05:52:37 -0600
From: Phil White <philwhite9@aol.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Exhaust Manifold material
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Ed Anderson:    I recall (if memory can be trusted?) that you are using 
304 stainless for your exhaust manifold.  I am wanting to make a 
tangential muffler for my 20B, and wonder if the following might last a 
reasonable time:  
1.   From the ports;  2" x .150 wall
2.   Tangential tube;  4" x .120 wall
3.   Exhaust pipe;  2.5" x .120 wall
4.   End caps on tangential pipe;  .125 plate
5.   Center tube (to help swirl, and to reinforce end caps);  3/4" x 
.080 wall  (wondered if it would be a good or bad idea to run cool air 
through this to cool it and the exhaust a bit, or better to leave the 
ends closed??)

    Are these walls heavy enough to last?  Or is using $175 worth of 304 
a waste of time and money compared to getting the more expensive 321 
stainless?  Your opinion is most welcome.

Phil in IL