----- Original Message -----
Sent: 07/26/2006 5:56 PM
Subject: [FlyRotary] Re: Inconel
I have a lot of experience with failure analysis. Used to do it with GM,
Ford, other warranty returns. One of my favorite experiences was solving a
million $ warranty issue on a tubing product. Although I'm not expert in this
area, I'd sure encourage considering other factors, other solutions.
In particular I'd encourage use of strobe lamp. Take cowl off, fire up
engine, use strobe. (yes, it's dangerous with prop on) You will suddenly have
appreciation for the forces involved. You should be able to predict failure
points with this test. Tack together the broken one to see what I mean.
The exhaust will turn into a sine shape at certain rpm. You will see huge
amount of movement on the busted one. Make a new design, compare movement to
predict how long it will last. A very minor design change can greatly improve
how much movement occurs.
I'm not sure this is applicable to you guys, but my exhaust design has
slip fit of two pipes instead of welding. It works phenomenal. I've had
conversation with other guys who welded instead and had failures. Same exact
application. So my exhaust floats in relation to the header. I just attach a
small bracket to the floating portion to prevent if from blowing off.
Truthfully, I never expected it to work, but it has quite well. I might have
pic if verbal description not adequate.