> Yep, that's who's design I copied - I even bought my 6" inconel tube
> from
> him because he had some left over from his muffler. The welder used
> the
> inconel welding rod that I bought. So I know it was the right stuff.
>
> The exhaust flange joint is welded both on the outside joint and on
> the
> inside joint. There is no possibility of weld failure there - the
pipe
> itself would have to tear/crack.
>
> Like I said - Inconel doesn't live long when there is flexing. So,
> maybe
> Atkins has his muffler supported and mine wasn't - although I've
> seen his a
> few times and didn't note any supports close to the can. It does
> look like
> he has a tab for support down the line a ways - that may damp out
> enough
> vibration to keep the flexing under control. For sure something was
> different!
>
> Joe Hull
> Cozy Mk-IV N31CZ (65 hrs - Rotary 13B NA)
> Redmond (Seattle), Washington
>
> -----------------------------------------------------
>
> The exhaust always breaks just next to the weld for some strange
> reason so the flange actually supports the tube.
>
> Here is some more info from Marks Wrathal site on welding
> tube to exhaust flanges. Many many racers do it all the time.
>
> http://www.wankel.org/
>
> " Weld only the engine side of the flanges. Four spot wells on the
> header side seems to be the way to go. Belt sand the flange faces
> then lap them on a piece of glass and a piece of oiled wet or
> dry paper."
>
> "Archie backed up this crucial point as follows:"
>
> "In hard core racing, the same problems (as occured on N214KW)
> arose a number of years ago, mostly in funny cars, but dragsters
> also. The common denominator, other than various grades of
stainless,
> was outside welds. Now you may see some tack welds on the outside,
> but the actual welding is done on the backside.(inside) Also in
> current use is a tube within a tube. I noticed the weld bead was
> quite wide, increasing the hazard, and may have contributed to the
> failure."
>
> Archie builds 7000 HP AA drag engines for a living and has several
> forums at OSH.
>
> This last trick is expensive but Everett Hatch came up with the
> idea. A ball flex joint is used right next to the block.
>
> Paul Lamar ...No rotor no motor.
>
>
> Paul and Joe,
> The more I learn about Everett Hatch the more impressed I am. The ball
> joint he uses would almost double as an anti-reversion cone. Besides
> relieving the pipe to block stresses note that the pipes just down
> stream also have inside slip fits. Very nice work.
> Bill Jepson
>
Were the welds heat normalized afterwards??
Gary Buster
I don't know if mine were heat normalized. Does that help the surrounding
metal? Because again, it wasn't the welds that broke - just the inconel all
around the joints.
Joe Hull
Cozy Mk-IV N31CZ (65 hrs - Rotary 13B NA)
Redmond (Seattle), Washington
I'll be gone for eight or ten hours. Will catch up tonight.
Trip to Racing Beat and Mazdatrix.
Paul Lamar
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