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Message
I live
in the state or Arnold, Racingbeat and Mazdatrix (CA), I spoke with
Arnold, Jim Mederer owner of Racingbeat - who is flying behind a
Lycoming btw., and some folks at Mazdatrix, (o.k. one of the last 3
statements is a artificial statement, I'm serious about rotaries though). A
few things I learned, Arnold does not have TFRs around him so he is better than
Bush in my book - since I got to fly patternwork in a Citabria while he was here
deplaning in San Jose. But back to the more graspable. 1750 degree F or 950ish C
is a -continuous- operating temp in a plane --- not in a car though. Metal
has temperature-inertia, talk about the heavy turbine housing, it does not heat
up enough in a million years - hmm make it 7 years, to loose a lot of material,
so in a car no problem for a few years*.
 Here is a graph of stainless (304 to
347) and Inconel (named altemp 625 here) - better stuff than the
stock turbine housing I think. You see stainless 304 at 1800 F
is gone mostly after a mere 100 hours.
So --- Best turbine housing I could find is stainless,
don't know what type, it s used in the Money etc. That knowledge is all
courtesy of Turbonetics. So the nice
(working) folks at Turbonetics (Garrett, Airresearch, Ray Jay, Allied Signal,
are all the same bunch of stockholders now) made me a turbo of mostly
Turbonetics parts except for the stainless hot housing. Btw. that housing is
rated at 1750 F continuous.
So that
turbo just came in a few weeks ago for $1415 +-$50 or so. It is good
for 160 HP at 25,000 feet. I'm sure you can get one too. Call 'em and ask for
Dick Vincent, very helpful guy. 1.30 A/R weighs about 25 lbs and needs a
separate wastegate. http://www.roadraceengineering.com/tial.htm
The 46 mm seems to be my current price
performance leader. $455
Now I'm pondering about the manifold, I think it is
down to Inconel 625 sheet (3/8" or 1/4") to build a boxy plenum like
manifold with a flange or tubular exit for the wastegate.
http://www.hightempmetals.com/hightemp/hitemp06.php4
looks like another $300 for the manifold.
($ 124 per square foot plus $75 misc charges)
If I wanted a simple flying plane I would
have stayed with my O-200 Vari EZ - but no, I need something to fiddle with
and improve upon.... 300 mph Long EZ in the works ;-)
greetings
Marko
* it does not take an engineer to build
something that lasts, it takes one to build something that barely
lasts.
Greetings,
I bet if you looked in
the archives, you'd see that I recently said the stock Mazda turbo could take
the heat. Well, I'm sorry to say that I no longer believe that.
I just dissected a "low
mileage" Series 5 turbo, and found that it was crack city inside. Man,
there isn't a single area of the high temp side of the housing that doesn't
have some sort of crack. All of these are hidden from external view, so
the one on my plane now is likely cracked in just the same way. The
latest exhaust manifold that I got from Ebay is also cracked, despite the "no
cracks" advertisement. Even with the crack, it's way better than the one
I currently have installed. Sigh...
I have now decided, that
the stock turbo is not going to stay on my plane for the rev-2 cowl. The
wastegate sucks, and turbo just isn't high enough quality. It's one
thing to run around in a car with cracked parts, but not in the
plane.
What does this
mean? Good question. I don't know yet. I don't
"need" the turbo, but I "want" it, so I'm going to look into an aftermarket
turbo. This one would be properly sized, have a stainless
exhaust manifold, and usable wastegate. Why do I do these
things to myself... If I come to my senses somewhere along the
line, I'll be going NA, and still having more power than I need for an
RV-3. I'd have to attend the EDKILL lecture though
:-)
Rusty (my kingdom for a
turbo that isn't cracked!)
eaten up by heat.gif
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