Al Gietzen wrote:

I have an inconel tangential manifold/muffler on my 20 - photo

attached (made by

Mark (can't remember last name), a la David Atkins).  The inconel

tubes extend

through the heavy Racing Beat Flange, but are welded on the outside -

not on the

inside.  Although having the tubes go through the flange may have made

the

welding easier, I'd guess that once you get that weld bead around

there the

resulting strength is no better then butting it up and wleding it.

Seems it

should be welded on the inside end so the flange can support the loads

on the

tube. There obviously will be significant thermal stress set up and

the unit

expands and the engine doesn't. Atkins has the same approach on his

13B and it

seems to be fine.  The distance between the ports is much less on his.

Am I

worried about mine?  Yep.  Short redoing a very expensive piece, I'll

do

frequent inspections.

Ick.  Those short headers from the exhaust flange to the muffler are

going to

crack at the muffler and/or the header.  Abel Ybarra (sp?) I think had

some

Inconel bellows on his exhaust system.  If you can find *2* (not 3!)

such bellows,

have the #1 and #3 rotor's headers cut out and replaced with the

bellows.  The #2

rotor's header would continue to rigidly mount the muffler, and the

bellows would

allow things to move.  The muffler would need a non-rigid weight support

to help

prevent cantilever cracking.

I need to get Rhino so I can draw what I mean.

Russell Kent

Not necessarily Russell. If all three outlets are tied
together with a racing beat type exhaust flange it might almost
track the expansion of the muffler.

Paul Lamar

 Al....can you give us an idea of what the cost from Dave Atkins was for

such an exhaust system?  Thank you. Paul Conner

The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.