Re: [FlyRotary] 20B exhaust (so far)

Kevin;

You may be able to get by without bellows in that configuration; but there will be some thermal and = support stresses, and at our exhaust temps, stress corrosion occurs in 321 (ask = David Atkins what happened to his SS exhaust). So when you do it over = you may want to go to inconel.

Also, I believe the most reliable = weld at the exhaust flange would be with a slip fit of the pipe through the = flange, and the weld on the other side. This allows the stress due to the expansion of the pipe relative to the flange to be carried against the = flange rather than by the weld.

FWIW,

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of kevin lane
Sent: Tuesday, March 01, = 2005 9:03 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = 20B exhaust (so far)

Buly - I = discussed this very point with my welder at great length. He has a lot of = experience fabricating exhaust for race cars, including rotaries. We decided = to chance not using the slip joints based on other cases where he didn't = use them. They can always be added if deemed necessary. I will have a ball = joint ahead of the muffler. I hope to have some dedicated airflow over = the manifold also. My guess is that this whole system will be changed = as I learn more of what I really need.

Kevin Lane Portland, OR
e-mail-> n3773@comcast.net
web-> http://home.comcast.net/~n3773
(browse w/ internet explorer)

=

----- Original Message = -----

From: Bulent Aliev

To:<= /font> Rotary motors in aircraft

Sent: Tuesday, March 01, 2005 6:06 PM

Subject: [FlyRotary] Re: 20B exhaust (so far)

Hi Kevin, I believe you must have some slip joints there to allow for = expansion. Without them you may get some cracking.
Buly

On 3/1/05 7:45 PM, "kevin lane" <n3773@comcast.net> wrote:

I have my engine = upside down right now while I work out oil cooler location. My welder = gave me some 321, so that's why the front rotor has an additional weld. = That plywood box is a spintech muffler mock-up, although it's not in place. = I plan to run it against the fire wall. With my belly scoop I can't = run the exhaust down there (damn!), so it will go out the side, a la turbine = engine I guess. I was lucky to have the welded up part able to slide on = around the engine mount, easy to forget when you are playing with individual = pieces.
Kevin Lane Portland, OR
e-mail-> n3773@comcast.net
web-> http://home.comcast.net/~n3773
(browse w/ internet explorer)