Mailing List flyrotary@lancaironline.net Message #33912
From: <Lehanover@aol.com>
Subject: Re: [FlyRotary] Re: Exhaust Update
Date: Tue, 10 Oct 2006 08:57:36 EDT
To: <flyrotary@lancaironline.net>
In a message dated 10/9/2006 11:16:41 P.M. Eastern Daylight Time, kenpowell@comcast.net writes:
Hi Joe,
Those are really great results.  I would love to know the HP increase.  Just a heads up - it looks like your new "header flange to pipe" (picture 5) was welded on the outside.  I think that 'acceptable practices' state that there should only be a tack weld on the outside and the actual structural weld should be on the inside.  What does everyone else say?   In any event be sure to keep an eye on the welds.

Ken Powell
Bryant, Arkansas
501-847-4721
C150 / RV-4 under construction
I suspect that idea came from looking at commercial built racing headers. Where automated welding equipment can be programmed to do a face weld, with no problem but welding from the pipe side would be very difficult. The weld bead is then machined slightly to attain a uniform surface with a high unit pressure to seal against the metal gaskets.
 
So long as penetration is good, fillet location should have no effect. This is not to say that pipes need not be supported to the engine to avoid stressing the joint. My headers are 1/2" carbon steel flanges with .130" wall tubes. No flange to tube failures since 1980.
 
Lynn E. Hanover 
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