Mailing List flyrotary@lancaironline.net Message #33921
From: Richard Sohn <unicorn@gdsys.net>
Subject: Re: [FlyRotary] Re: Exhaust Update
Date: Tue, 10 Oct 2006 16:24:12 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
 
----- Original Message -----
From: Joe Hull
Sent: Monday, October 09, 2006 10:10 PM
Subject: [FlyRotary] Re: Exhaust Update

>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

 

Ken,

Yes, I’ve heard that from PL’s list – but haven’t seen pictures of any other flying Rotary that is welded that way. I was going to tell Aircraft Exhaust to only weld it on the inside but forgot. But I’m not sure there is agreement about this among the rotary flyers.

 

Joe Hull

 

I can only second the "inside weld/out side tag" principle. I did it 6years ago on the SOOB and still flying, and also on the one rotor on the test stand with no problems. I really only copied that from automotive headers, understanding the rational.

If it is welded on the outside only, the pipe will start to erode at the beginning inside, where it is not physically connected to the flange because of excessive temperature buildup.

 

Richard Sohn
N-2071U

 

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