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Hi Scott,
That makes me feel a lot better. I see you have the proper welds on the inside. Though I think it is proper to then only tac around the outside, I'm not sure how much it matters.
It does look like a very nice piece of workmanship, and I have no firm reason to say that it will not hold up. Please just keep a very close eye on it. There have been at least 3 totaled aircraft because welds did not hold up on exhaust systems - and none of them had turbos to support.
The product made by Garrett is a complete manifold. They don't make them anymore. But they are of very high quality and reasonably priced if you can find one around (heavy though).
the Drain line itself needs to remain the full 3/4" or so all the way back. I tried a -6 line and kept spilling oil out my exhaust. It looks to me like you are using -8 but it could just be a problem with the picture. Since it is gravity fed there needs to be an air-fluid level throughout that line. Otherwise, any slight amount of air pressure in the sump will prevent the oil from draining and it will blow oil out the exhaust.
Lastly, even back when I had marginal cooling I could run on the ground at idle indefinitely. Now I can run at moderate power indefinitely on the ground. Don't overestimate the effect of flight on cooling. In pushers it makes a big difference, but I found that the extra power used in flight offset any improvement in airfow. Also, I recommend a coolant redline of 200 but that should be only for very short duration. Keep your coolant below 180 any you will be much happier. It will give you a greater margin from detonation (which for me is very tied to coolant temp). Running without an intercooler (for now) that will be even more important to you.
Nice Job though. Can't wait to see it fly.
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Tue, Jun 24, 2008 at 11:53 AM, < SHIPCHIEF@aol.com> wrote:
Dave;
Thanks for the comments. I want to 'debate' a couple of points and ask a question, don't worry, I won't get emotional about my baby.
I could not use the stock cast manifold because Fred Breese's mount didn't leave enough room. I got an XS manifold same as one posted on the forum in the last few days. It didn't fit either.
The manifold I designed is a combination of 'small and tight' to the engine to keep the cantalever loads low, and uses large diameter .060 wall 321 for heat resistance and strength.
To protect the engine flange to tube weld from heat damage, I welded in some standard Burns Stainless 321 tapered 2" - 1.75" nozzles, perhaps these will be visible in the attached photo. The 2.5" outer tubes are butt welded .25" away from the 2" port, and the nozzle liner prevents direct heat impingement.
I didn't think the external weld would be a problem on the turbo support flange?
To keep the cantalever load under control, I added two 1/2" straps to join the tops of the two flanges.
You said garrett makes a nice one to support a T0-4. A nice what? support flange with brackets? I didn't understand what you meant...
The lack of insulation, I agree. I'm just now running my fifth time, and still inspecting for any kind of problem, like leaks etc, so insulation will be an ongoing affair.
The turbo oil drain line bigger? It's already the same size as the exit from the bearing housing and the point of entry into the engine, what is appropriate and why?
Thanks;
Scott
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