Message-ID: <40377D1E.90400@mail.viclink.com>
Date: Sat, 21 Feb 2004 07:45:34 -0800
From: Perry Mick <pjmick@mail.viclink.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] exhaust
References: <list-3001353@logan.com>
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sqpilot@earthlink wrote:

>My 13b engine is ready to run....I ordered a VAM muffler, but since it has
>not yet happened, I was wondering if I could get away with using the stock
>cast iron manifold with a straight pipe attached to it, which would exit
>through the bottom of the cowling. I should mention that this is on a
>pusher. George Graham told me that he was using a straight, (or slightly
>bent) pipe, and possibly Perry Mick is or was using the stock cast iron
>manifold?  My thinking is that although it is heavy, it might possibly
>absorb a lot of the initial heat as it is exiting the exhaust ports, acting
>like a heat collector, and I might not need expensive inconel or 321
>stainless after the exhaust goes through the stock manifold first?  Would
>the cast iron manifold absorb much of the heat and possibly muffle some of
>the noise as it is bounced around inside of the stock manifold?  I'm
>probably grasping at straws, but with all the knowledge and experience in
>this group, I figure it wouldn't hurt to ask.  Thanks to all for your
>opinions and advice.  Paul Conner, 13b powered SQ2000
>
>
>  
>
Yes I still use the stock exhaust manifold. It takes all the heat abuse. 
I have a short pipe made from standard automotive stuff at a muffler 
shop, it shows no sign of wear after 5 years and 440 hours because the 
cast iron takes the direct hit. No stainless or iconel or anything 
special. You want to be sure to keep the heatshields on.

-- 
Perry Mick
http://www.ductedfan.com