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,
Al
-----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.
----- Original Message -----
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
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