For what it’s worth, George,  I had my exhaust manifold made out of the stainless steel pipe used for stair railing that Mark mentioned.  The walls are approx 0.10 -0.12” thick.  Mine has lasted over 500 hours and 10 years.  It appears to be 304 SS, but I can not swear to that.  There is some minor scaling  and it does eventually turn a rust color – at least mine did.  I’ve been very please with it.  It’s wall thickness also makes it easier to weld in bungs for O2 and temperature sensors than thinner wall tubing.  Also it was much cheaper than buying SS exhaust tubing and you could get just about any degree bend you wanted from stock rather than paying cost for special bending.

 

Ed

 

 

----- Original Message -----

From: Mark Steitle

To: Rotary motors in aircraft

Sent: Thursday, February 05, 2009 7:59 AM

Subject: [FlyRotary] Re: 20B manifold

 

George,

 

If you're asking how thick my 20B exhaust flanges were, they were 1/2" (12mm).  I made them this thick so they would provide support for the exhaust system.  Tubes were a press fit and were welded from the back side.  That part of the design has worked great... although probably heavier than necessary. 

 

Regarding the Renesis manifold, there is a bunch of cast material that could be removed to lighten it up.  But I agree that it would be best to build a lightweight exhaust system from scratch.

 

Mark S.

On Wed, Feb 4, 2009 at 3:36 PM, George Lendich <lendich@optusnet.com.au> wrote:

Mark,

How thick was that again, 1.6mm ?

George ( down under)

 

Robert,

Bite the bullet and make one from scratch, Just make the thick flanges from SS ( 304 or 316) and use the hand rail pipe as suggested - cheapest and best for the 3 rotor.

Sounds a lot lighter than the cast manifold.

George ( down under)

----- Original Message -----

From: Mark Steitle

To: Rotary motors in aircraft

Sent: Thursday, February 05, 2009 12:10 AM

Subject: [FlyRotary] Re: 20B manifold

 

Robert,

 

I have one that came with my 20B.  I don't want to sound negative, but I don't think it is realistic to use on an a/c.  First, it is incredibly heavy because it is designed to incorporate the twin turbos.  And it is made of cast iron, so it would probably melt at prolonged WOT operation.  And the passages are very restrictive to exhaust flow.  I could weigh mine and send some pictures if you wish.  Sorry, but I don't want to get rid of it because I have plans for a 3-rotor auto installation where it would be useable.  Maybe you could modify a Renesis manifold to fit.  It would require some welding, but it is probably more likely to work than the original 20B manifold. 

 

The cheapest manifold would be to use 304SS handrail material.  I built my first manifold using that material and after 100 hours it looks like it would last for a very long time.  Ed Anderson has been using this material on his a/c for a long time.  My exhause flange material was 1/2" mild carbon steel and it was holding up fine as it doen'st see the high heat that the pipes do.  The problem was with the mufflers.  They take a real beating.  Try to space the muffler as far away from the engine as possible. 

 

Mark S.

 

 

On Wed, Feb 4, 2009 at 7:43 AM, Rob <rob@mum.edu> wrote:

Al and Greg,

Thanks for your replys on this subject. I realize the manifold would be too heavy but I was hoping I could widdle it down some how. Greg, I would be interested in your suggestion for doing that. I'm putting this 20B in a BD-4.

Robert

 

Robert Bollinger
MR722 MUM
Fairfield IA 52557
(641)472-7000 ex2068
(641)919-3213 cell
rob@mum.edu

----- Original Message -----

From: Greg Ward

To: Rotary motors in aircraft

Sent: Tuesday, February 03, 2009 11:10 PM

Subject: [FlyRotary] Re: 20B manifold

 

Al, you don't want the stock exhaust.  Get one built.  If you want to know one way it's done, let me know.

Greg Ward

Lancair 20B in progress

----- Original Message -----

From: Al Gietzen

To: Rotary motors in aircraft

Sent: Tuesday, February 03, 2009 8:25 PM

Subject: [FlyRotary] Re: 20B manifold

 

 

Does anyone on this list have a 20B exhaust manifold that came with their engine that I could buy?

 

No; but I do know the thing is massively heavy.  I looked at one when I got my engine, and decided quickly it was not very interesting for an aircraft.  Maybe if radically modified . . . Just my opinion.

 

Al G