ericmpmail-rv10(at)yahoo.
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 Posted: Fri Apr 28, 2006 12:33 pm Post subject: Auto engine conversion with good links for Lycoming operatio |
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I had a subaru H6 engine in my garage for a short time
and I looked at Egg for quite awhile as well. I came
to the same conclusions, I think it might be ok for
two-seaters but the H6 does not have what it takes for
the high power operation needed in the RV-10. I'm
still looking at rotaries - no showstoppers (for me)
yet.
Air-cooled lycomings have years of refinement and very
good power/weight ratio but they do operate with
little margin in some areas and need a fairly high
level of care. For example, leaning at high power
settings,EGT/CHT limits near the material limits,
start procedures, manual mixture, 100LL, oil
consumption, life-limited parts, operating temp range
and expecations on usage.
Modern ignition and fuel balancing overcome some of
these. 6 probe CHT/EGT help and FADEC will likely be
more common in the future. If you have to have a
lycoming than the 6-cylinder is a good choice as it is
much smoother than the 4 cylinder.
Here is a site with great info:
http://www.buy-ei.com/Manuals/The%20Pilots%20Manual%20(by%20EI).pdf
Read page 6 for info on lycoming IO-540 fuel burn at
rich and lean settings - good graph too.
and of course Lycoming's site and flyer key reprints:
http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/index.html
Concerning reliabilty, for auto or air, it is usually
related systems that fail and not the engine itself.
Lack of fuel seems to be the most common (vapor lock,
plugged, or just out...) The best engine in the world
will not help if the underlying aircraft systems are
deficient. I bet Van's FWF packages have "saved" many
builders by providing a good foundation of tested
systems.
Eric
--- "RV Builder (Michael Sausen)"
<rvbuilder(at)sausen.net> wrote:
| Quote: | I spent a considerable amount of time looking into
auto conversions with Eggs being the most promising.
I really did not want to put an old Lycosaur into
my -10. However I was unable to find any solid data
to support some of the claims being made and he
seems to be constantly 6 months or longer behind his
scheduled delivery dates. Even some of his
staunchest supporters privately told me they
wouldn't use his new engine in something like a -10
until it is proven over the next two years. The new
redrive, high operating RPM's, and past history of
Egg claiming HP numbers that were shown to be wrong
really put me off eventually. Also, when I pushed
the issue around constantly changing HP numbers I
was banned from his group. Nice! It basically came
down to a trust issue with me, I think Egg is
probably genuine in his resolve that the engine can
do what it says but I want real numbers on paper and
Egg just would not do it. With myself and 3 other
souls on board I could not in good conscious select
an unproven engine with NO real world data. By
going with Barrett I will pay more in fuel but I
have 100% confidence in his reputation and his
ability to deliver what he says. Also having it run
on the dyno helps  .
Now I know there are several -10 builders going
with the Subie and I honestly wish them all the best
and really hope the engine meets it's computed
numbers (he does not dyno any engines) as this would
be an excellent alternative to the engines we
usually use. I still think that it would be an
excellent engine for any of the 2 seat RV's. Not
flaming Egg, just stating my opinions along with
some facts.
Michael Sausen
RV-10 #352 Working on Fuselage
Do Not Archive
Recent RV-10 Build Activity
<http://www.mykitlog.com/display_project.php?project_id=22>
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[quote]
________________________________
From: owner-rv10-list-server(at)matronics.com
[mailto:owner-rv10-list-server(at)matronics.com] On
Behalf Of Doerr, Ray R [NTK]
Sent: Friday, April 28, 2006 7:09 AM
To: rv10-list(at)matronics.com
Subject: RE: Autogas for 540
No I would not buy another auto conversion. I am an
engineer and I don't like what I've seen in terms of
engineering for these firewall forward packages. It
is more like engineering by trial and error and
unfortunately I had to be the guy that found an
error. That being said, I do think the Subaru is a
great engine, but currently the displacement isn't
large enough for these engines to be running at 2700
RPM with no gear reduction drive. Now is Subaru
came out with a boxer 8 cylinder in the 5.0 liter
range with dual plugs/ignition and dual built in
alternators for them, a very small gear reduction
drive that would maybe run the engine at 3,500 RPM
with prop at 2700 would give a hassle free 2000+
hour TBO. Some of the things I've found that were
not addresses very well were Fuel delivery, location
of the pumps (cabin, engine side of firewall, in the
tank etc), air flow for oil and water coolers.
Some of the other factors I've
considered this time round is to ensure that
everyone in the aviation industry can put a price on
the components that make up my plane. Example: The
engine even as a core as a define value, the Garmin
components in the panel, the airframe, prop etc.
This way if I every needed to sell it/part it out
for any reason, I could get a fair price for the
individual piece.
Thank You
Ray Doerr
CDNI Principal Engineer
Sprint PCS
16020 West 113th Street
Lenexa, KS 66219
Mailstop KSLNXK0101
(913) 859-1414 (Office)
(913) 226-0106 (Pcs)
(913) 859-1234 (Fax)
Ray.R.Doerr(at)sprint.com
--
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