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deej(at)deej.net
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 Posted: Mon Nov 03, 2008 6:33 pm Post subject: Crossflow Subaru Engine |
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<http://www.sdsefi.com/air51.htm>
-Dj
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Dj Merrill - N1JOV
Sportsman 2+2 Builder #7118 N421DJ KR-2 Builder N770DJ
http://deej.net/sportsman/ http://deej.net/kr-2/
"Many things that are unexplainable happen during the construction of an
airplane." --Dave Prizio, 30 Aug 2005
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nuckolls.bob(at)cox.net
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| Posted: Mon Nov 03, 2008 8:12 pm Post subject: Crossflow Subaru Engine |
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At 01:12 PM 11/3/2008 -0700, you wrote:
| Quote: |
Some of us know that most current aircraft engines were actually developed
in the sixties, and have worked on both types of engine for years, and
know what the actual differences are, and what the limited benefits the
newer design auto engines have. For instance Porsche did their damnest to
design an engine to improve on the Lycoming IO-360. The result was
heavier, no more powerful and used more fuel, and failed on the market.
That design was done in the late 80's, so don't tell me about the great
new auto technology.
|
Are you suggesting that one failure of an automotive
derivative in the marketplace is a benchmark for all
such endeavors? For every success in the marketplace,
there are dozens of failures in the lab or engineering
test vehicles.
The first engines installed on the B-29 were the most
parts-intensive products of their time and failure rates
on the order of 1 every 10-40 hours. The first fielded
B-29's were pampered to the extreme to keep the airplane
marginally useful while development efforts worked out
the bugs. THOSE engines were produced by a company with
a great deal of experience in the design and manufacture
of aircraft engines.
Toyota built some air racing engines . . . but we're
not seeing those on TC aircraft either. But then, why
put $millions$ into developing an engine that will be sold
at perhaps 1000 pcs per year when the same $millions$ might
produce an engine that is sold into millions of cars?
As I suggested earlier, the breakthrough developments
will probably not come from the established suppliers
to the marketplace. This is demonstrated by the fact that
the most successful automotive derivatives flying are
not offered by the original manufacturer of the
engine. The fact that Toyota or Porsche stubbed
their toes was probably predictable but the lessons
learned were invaluable.
But it's disingenuous to paint all automotive
conversion efforts with a brush dipped into the
failures of a few.
Bob . . .
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Jerry Cochran
Joined: 10 Jan 2006
Posts: 111
Location: Wilsonville, OR
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| Posted: Tue Nov 04, 2008 11:01 am Post subject: Crossflow Subaru Engine |
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Folks,
At one time I was very interested in a converted Subaru. IMO, there is a wonder of technology in this fine engines... in cars. Problem is for aircraft... It needs a gearbox (PRSU heavy), also has to get rid of the same amount of heat as a Lycosaurus per HP and do it with radiators (heavy, heavy, heavy), usually needs redundant electrical systems (batteries, heavy), special propellers, etc., etc. the list goes on.
Did I mention these are a lot heavier than LycoCont?
Buyers should be aware that all these products from vendors are "experiments in progress". For a time I ran a website devoted to alternative engines and heard numerous complaints about vendors and their problems with non delivery, failed products, poor business practices, and lawsuits (Crossflow) by customers.
I believe Eggenfellner has really tried to get a good foothold in this market and is pretty honest, but assuming the best of intentions, has orphaned engines, the STI Subaru for instance.
The idea that these are "plug and play" and can just be popped into your airframe like a Lyco is false, and has led to many folks with empty pockets. So, do extensive research before committing to same.
Be totally prepared to do your own engineering, also, just like the author of this thread. Good thing he's an EE.
Get your money back? Not a chance. Usually these folks fund their operations with deposits. Other words, to deliver end product, they rely on current deposts, and this is very common in aviation.
As usual, my dime's worth,
Jerry Cochran
Sherwood, OR
18XP RV-6a 150hrs on Superior XP-IO-360 169 knots at 8500' 7.7 GPH LOP
In a message dated 11/4/2008 12:01:31 AM Pacific Standard Time, aeroelectric-list(at)matronics.com writes:
| Quote: | Are you suggesting that one failure of an automotive
derivative in the marketplace is a benchmark for all
such endeavors? For every success in the marketplace,
there are dozens of failures in the lab or engineering
test vehicles.
The first engines installed on the B-29 were the most
parts-intensive products of their time and failure rates
on the order of 1 every 10-40 hours. The first fielded
B-29's were pampered to the extreme to keep the airplane
marginally useful while development efforts worked out
the bugs. THOSE engines were produced by a company with
a great deal of experience in the design and manufacture
of aircraft engines.
Toyota built some air racing engines . . . but we're
not seeing those on TC aircraft either. But then, why
put $millions$ into developing an engine that will be sold
at perhaps 1000 pcs per year when the same $millions$ might
produce an engine that is sold into millions of cars?
As I suggested earlier, the breakthrough developments
will probably not come from the established suppliers
to the marketplace. This is demonstrated by the fact that
the most successful automotive derivatives flying are
not offered by the original manufacturer of the
engine. The fact that Toyota or Porsche stubbed
their toes was probably predictable but the lessons
learned were invaluable.
But it's disingenuous to paint all automotive
conversion efforts with a brush dipped into the
failures of a few.
Bob . . . |
Plan your next getaway with AOL Travel.ol?redir=http://travel.aol.com/discount-travel?ncid=emlcntustrav00000001">Check out Today's Hot 5 Travel Deals!
[quote][b]
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klehman(at)albedo.net
Guest
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| Posted: Tue Nov 04, 2008 2:42 pm Post subject: Crossflow Subaru Engine |
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Which is all mostly true but mostly surmountable with effort.
My one off 2.2 liter subaru with dual multi port EFI and electrical
systems comes in at about the same weight as an 0-320. The mission
weight with fuel for the same range is arguably quite a bit less. SFC's
are similar to a Lyc running LOP but I happily cruise at very low power
(just over 4 gph) with no fouling, temperature, or mixture issues. Yet
it seems to match a fixed pitch 0-320 for take off and climb
performance. All with an economical Warp Drive prop. I cruise slow but I
usually catch up to my buddies (same aircraft types) by the time they've
finished refueling. At the end of the day I've burnt about half the fuel
quantity and it is cheaper mogas. I don't participate in the "how hot is
your engine" conversations, and I'm there in time for the first beer 
My only issue has been the gearbox which in my case is indeed heavy and
expensive. But so far I'm happy with the second one. Conversions are
over hyped and definitely not for everyone but they can be absolutely
wonderful for some applications like mine. 0-320 STOL performance, the
advantages of EFI, rotax 912 fuel consumption in cruise, hassle free
winter flying, etc.
Downside includes: I'm on my own if anything needs repair. Since I avoid
leaded fuel, it is sometimes less convenient obtaining mogas on long
trips. (Long means more than 7 hours in my case). It is getting harder
to avoid alcohol but I will burn it in preference to 100LL as long as it
is consumed within about 24 hours.
Ken
(I promise not to say any more on this list)
Jerry2DT(at)aol.com wrote:
| Quote: | Folks,
At one time I was very interested in a converted Subaru. IMO, there is a
wonder of technology in this fine engines... in cars. Problem is for
aircraft... It needs a gearbox (PRSU heavy), also has to get rid of the
same amount of heat as a Lycosaurus per HP and do it with radiators
(heavy, heavy, heavy), usually needs redundant electrical systems
(batteries, heavy), special propellers, etc., etc. the list goes on.
Did I mention these are a _lot_ heavier than LycoCont?
Buyers should be aware that all these products from vendors are
"experiments in progress". For a time I ran a website devoted to
alternative engines and heard numerous complaints about vendors and
their problems with non delivery, failed products, poor business
practices, and lawsuits (Crossflow) by customers.
I believe Eggenfellner has really tried to get a good foothold in this
market and is pretty honest, but assuming the best of intentions, has
orphaned engines, the STI Subaru for instance.
The idea that these are "plug and play" and can just be popped into your
airframe like a Lyco is false, and has led to many folks with empty
pockets. So, do _extensive research_ before committing to same.
Be totally prepared to do your own engineering, also, just like the
author of this thread. Good thing he's an EE.
Get your money back? Not a chance. Usually these folks fund their
operations with deposits. Other words, to deliver end product, they rely
on current deposts, and this is very common in aviation.
As usual, my dime's worth,
|
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echristley(at)nc.rr.com
Guest
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| Posted: Wed Nov 05, 2008 5:38 am Post subject: Crossflow Subaru Engine |
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Jerry2DT(at)aol.com wrote:
| Quote: |
The idea that these are "plug and play" and can just be popped into
your airframe like a Lyco is false,
The idea that a Lyco is "plug and play" and can just be popped into your
|
airframe is false also. A proper Lyco installation requires no less
engineering than an auto installation. What is different is that
usually all the engineering has already been done by the plane's
designer. It is not at all uncommon to here of engine problems in a new
airplane design. Those problems are generally dismissed with a "Yeah,
we know how to handle that" or "That's just the way Lycomings are."
(Oil seeping cases anyone?)
It boils down to the simple fact that using an alternative engine means
that you are working on an alternative airplane design. You can't pull
just one string of a spider's web. For planes that are designed for an
alternative engine*, just popping in a Lyco would be the difficult choice.
*If it is designed for an alternative engine, wouldn't that make the
Lyco the alternative?
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frank.hinde(at)hp.com
Guest
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| Posted: Wed Nov 05, 2008 8:58 am Post subject: Crossflow Subaru Engine |
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I havent replied to this thread but having built both a Lycoming and a soob powered airplanes here are my thoughts.
As others have said be prepared to do some engineering with an auto conversion. The problem is not normally with the engine itself, its if the engine has been "rebuilt" and the ancillery components like the gearbox have a lot less development hours than the engine itself.
As an installation is only as strong as the weakest link then it is not unusual to find some issues...
Fuel consumption for the same amount of power are really not much different between a Lyc and a soob...Now a Lyc with fuel injection can be run LOP which improves the BSFC by quite a bit. I don't honestly know if automotive FI systems have this option.
One thing not mentioned below is cooling drag. This is a hotly debated issue. In a slow airplane its probably not going to make any difference, but in a fast airplane the cooling drag is a significant part of the overall drag. A radiator has a lower temp than a cylinder head. This translates into more cooling flow required for the same amount of horsepower rejected.
I have seen a few RV's with water cooled engines that have larger exits scoops for this very reason...How much does this translate into increased fuel flow to fly at the same speed as an air cooled motor has yet to be determined.
I think the old wives tale about "lycomings need 100LL" is now long dead and buried..a lot of them are run on mogas and mine is now run on 10% ethanol without a problem. I too will avoid 100LL if I can.
The big advantage as far as I can see for an automotive install is the rebuild cost will be considerably lower than a lyc.
Frank
Rv7a IO360..330 hours
Zenair zodiac Ea 81 soob..4000 hours
Do not archive
--
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