subaru diesel

Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf

by
--
Volem rien foutre al païs!
Philippe Vessaire Ò¿Ó¬

"Philippe Vessaire" wrote in message
news:19459447.yEvPs9oxTh@GastonCoute...
Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf


Holy crap! That thing has the peak torque, and it is almost a level line,
from about 1600 rpm to about 2400 rpm!

That sucker should really pull a big prop, and well!
--
Jim in NC

"Morgans" wrote in message ...

"Philippe Vessaire" wrote in message
news:19459447.yEvPs9oxTh@GastonCoute...
Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf


Holy crap! That thing has the peak torque, and it is almost a level line,
from about 1600 rpm to about 2400 rpm!

That sucker should really pull a big prop, and well!
--
Jim in NC




Is the price of diesel fuel 25% above gasoline prices everywhere?
Jet A costs the same as 100LL now also, so what is the benefit?

On Fri, 21 Mar 2008 22:06:30 -0400, "Morgans"
wrote:


"Philippe Vessaire" wrote in message
news:19459447.yEvPs9oxTh@GastonCoute...
Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf


Holy crap! That thing has the peak torque, and it is almost a level line,
from about 1600 rpm to about 2400 rpm!

That sucker should really pull a big prop, and well!

Like I said!

--
Posted via a free Usenet account from http://www.teranews.com

On Sat, 22 Mar 2008 20:00:35 -0400, "Blueskies"
wrote:


"Morgans" wrote in message ...

"Philippe Vessaire" wrote in message
news:19459447.yEvPs9oxTh@GastonCoute...
Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf


Holy crap! That thing has the peak torque, and it is almost a level line,
from about 1600 rpm to about 2400 rpm!

That sucker should really pull a big prop, and well!
--
Jim in NC




Is the price of diesel fuel 25% above gasoline prices everywhere?
Jet A costs the same as 100LL now also, so what is the benefit?



The only benefits are slightly lower fuel burn (in pounds per hour -
sig ificantly more difference in gallons per hour) and less liklihood
of not being able to get correct fuelin the mid-long term.
Jet A will be around for a while. 100LL has a limited lifespan, and
non-aviation gasoline is always a moving target.

--
Posted via a free Usenet account from http://www.teranews.com

"Blueskies" wrote in message
...

"Morgans" wrote in message
...

"Philippe Vessaire" wrote in message
news:19459447.yEvPs9oxTh@GastonCoute...
Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf


Holy crap! That thing has the peak torque, and it is almost a level
line, from about 1600 rpm to about 2400 rpm!

That sucker should really pull a big prop, and well!
--
Jim in NC


Is the price of diesel fuel 25% above gasoline prices everywhere?
Jet A costs the same as 100LL now also, so what is the benefit?



1. Most diesels wear more slowly than gas engines. The fuel is a better
lubricant than gasoline is, and the combustion products are a bit more
benign.
2. No ignition system needed.
3. Turbocharging a diesel is a win-win proposition. EGT is lower, so turbo
system parts last as long as the engine, usually. Turbocharging improves
both performance and fuel efficiency (not always true for gassers).
4. Full power available up to about 15K feet for most auto-type
turbodiesels.
5. Automatic mixture control.
6. No carb icing or vapor lock.
7. Lower fire risks.
8. I can make biodiesel for 67 cents a gallon. You or I can buy off-road
diesel or heating oil for much less than either auto gas, avgas or jet A.
9. For a given trip, less fuel is needed, both in volume and weight. 25%
to 35%, depending on the trip profile. If the diesel is turbocharged and
gasser is not, the diesel's ability to cruise significantly higher may
result in a bigger efficiency spread.
10. Props are more efficient at lower RPMs, usually. Diesels have torque
to turn props slow in cruise, like a turboprop (1800-1900 RPM), giving maybe
another 5% efficiency gain, and a quieter cabin to boot.

Given time, I can think of more. Please note that gas engines were
abandoned decades, nay, scores of years ago in other transportation sectors.
It will be the same in aviation if the weight difference shrinks enough.

DS

"Dale Scroggins" wrote in message
...

"Blueskies" wrote in message
...

"Morgans" wrote in message
...

"Philippe Vessaire" wrote in message
news:19459447.yEvPs9oxTh@GastonCoute...
Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf


Holy crap! That thing has the peak torque, and it is almost a level
line, from about 1600 rpm to about 2400 rpm!

That sucker should really pull a big prop, and well!
--
Jim in NC


Is the price of diesel fuel 25% above gasoline prices everywhere?
Jet A costs the same as 100LL now also, so what is the benefit?



1. Most diesels wear more slowly than gas engines. The fuel is a better
lubricant than gasoline is, and the combustion products are a bit more
benign.
2. No ignition system needed.
3. Turbocharging a diesel is a win-win proposition. EGT is lower, so
turbo system parts last as long as the engine, usually. Turbocharging
improves both performance and fuel efficiency (not always true for
gassers).
4. Full power available up to about 15K feet for most auto-type
turbodiesels.
5. Automatic mixture control.
6. No carb icing or vapor lock.
7. Lower fire risks.
8. I can make biodiesel for 67 cents a gallon. You or I can buy off-road
diesel or heating oil for much less than either auto gas, avgas or jet A.
9. For a given trip, less fuel is needed, both in volume and weight. 25%
to 35%, depending on the trip profile. If the diesel is turbocharged and
gasser is not, the diesel's ability to cruise significantly higher may
result in a bigger efficiency spread.
10. Props are more efficient at lower RPMs, usually. Diesels have torque
to turn props slow in cruise, like a turboprop (1800-1900 RPM), giving
maybe another 5% efficiency gain, and a quieter cabin to boot.

Given time, I can think of more. Please note that gas engines were
abandoned decades, nay, scores of years ago in other transportation
sectors. It will be the same in aviation if the weight difference shrinks
enough.

DS

Of course there are all kinds of diesels just like there are all kinds of
spark ignition engines. Generalizations need to be made carefully. Over
the road diesels are heavy to absorb the heavy bottom end loads with less
expensive cast iron blocks. Automobile diesels tend to be heavy since there
is no compelling reason to make them light.

The one absolute is that diesel fuel will be around for a long time in one
form or another. The 'gotcha' is that the rest of the world runs on diesel
and when developing economies like India and China demand more fuel it will
be diesel they are after so the price is likely to remain high. Hopefully,
biodiesel will be cheap.

Aircraft diesels are very special since they need to be both powerful and
light demanding high tech metalurgy like titanium rods. To keep the weight
down, 2-stroke diesels look good. Opposed piston 2-stroke diesels look even
better since the bottom end loads are spread across two crankshafts.

The Subaru oil burner looks good but then so does the DeltaHawk and the
little opposed piston aircraft diesels from the UK.

Bill D

"Bill Daniels" bildan@comcast-dot-net wrote

The Subaru oil burner looks good but then so does the DeltaHawk and the
little opposed piston aircraft diesels from the UK.

Do let me know when the Delta Hawk is available for sale.

I won't be holding my breath, until then.

I can't survive without breathing that long.
--
Jim in NC

On Mar 22, 9:33 pm, "Dale Scroggins"
wrote:
"Blueskies" wrote in message

...



"Morgans" wrote in message
...

"Philippe Vessaire" wrote in message
news:19459447.yEvPs9oxTh@GastonCoute...
Hello

Torque curve page 6

http://www.subaru.fr/special/pdf/doc...esel_lo_08.pdf

Holy crap! That thing has the peak torque, and it is almost a level
line, from about 1600 rpm to about 2400 rpm!

That sucker should really pull a big prop, and well!
--
Jim in NC

Is the price of diesel fuel 25% above gasoline prices everywhere?
Jet A costs the same as 100LL now also, so what is the benefit?

SNIP
2. No ignition system needed.

Not to be a ball-buster, but the injection systems for the new
generation of diesels is incredibly fancy. From a risk analysis
standpoint, it is hard to say whether this system in place of magnetos
is a gain or a loss.

3. Turbocharging a diesel is a win-win proposition. EGT is lower, so turbo
system parts last as long as the engine, usually. Turbocharging improves
both performance and fuel efficiency (not always true for gassers).

True, but boost levels in diesels inversely effect their reputation
for reliability.

SNIP

8. I can make biodiesel for 67 cents a gallon. You or I can buy off-road
diesel or heating oil for much less than either auto gas, avgas or jet A.

Biodiesel gels at a higher temp than does winter diesel, and be damned
sure you have no rubber in the fuel system. And the 67 cents is
quoted for recycled oil. Not my first pick at altitude.

9. For a given trip, less fuel is needed, both in volume and weight. 25%
to 35%, depending on the trip profile. If the diesel is turbocharged and
gasser is not, the diesel's ability to cruise significantly higher may
result in a bigger efficiency spread.

This is dependent on tuning the boost map, and whether the blower is
big enough. Off the shelf this may or may not be true. I have not read
flight tests for any new European diesels which have been impressive
in high altitude performance. I doubt this is because of any
fundemental flaws, but rather performance tuning.

10. Props are more efficient at lower RPMs, usually. Diesels have torque
to turn props slow in cruise, like a turboprop (1800-1900 RPM), giving maybe
another 5% efficiency gain, and a quieter cabin to boot.

Given time, I can think of more. Please note that gas engines were
abandoned decades, nay, scores of years ago in other transportation sectors.
It will be the same in aviation if the weight difference shrinks enough.

DS

I dig your enthusiasm. Please post if you hear of any new diesel/
biodiesel aviation projects. I would be interested in reading any
related results. I believe that the new generation of diesels are the
long term solution for keeping GA operating costs down. But it will
take a while.

-Matt

wrote in message
...
On Mar 22, 9:33 pm, "Dale Scroggins"
wrote:

SNIP

SNIP
2. No ignition system needed.

Not to be a ball-buster, but the injection systems for the new
generation of diesels is incredibly fancy. From a risk analysis
standpoint, it is hard to say whether this system in place of magnetos
is a gain or a loss.

Fuel control systems for new generation turbine engines are also incredibly
fancy. They have more redundancy than automotive systems, and some have
mechanical back-up, but from recent news reports, aren't utterly reliable.
But they seem to be tolerably reliable.

Subaru appears to be using common rail and electronic injection control, but
it's likely their engine could be adapted to a more basic mechanical system
if desired. Subaru probably doesn't build the injection components, but
purchases them from a specialty manufacturer. The VW TDI engine, for
example, uses electronic injection control when installed in a Jetta, but
when sold as a stationary engine, uses a purely mechanical injection system
provided by Bosch.

Even mechanical diesel injection systems have failure modes, of course. So
do gasoline injection systems and carburetors. None of them are utterly
reliable, but all seem to be tolerably reliable.

Leaving fuel control concerns aside for now, however, the fact remains that
diesels do not require electrical ignition systems. A gas engine depends
upon air, compression, fuel control, and ignition. The diesel depends upon
air, compression, and fuel control.

Aircraft ignition systems are high cost, high maintenance, and can interfere
with other aircraft systems. I've maintained, troubleshot, and repaired
these systems for thirty years. I would not miss them if they fell from
favor. During the same period, I've maintained, troubleshot, and repaired
aircraft fuel control systems from carburetors to FADEC. Diesel electronic
fuel control systems are not any more complex and need not be any less
reliable than these systems.


3. Turbocharging a diesel is a win-win proposition. EGT is lower, so
turbo
system parts last as long as the engine, usually. Turbocharging improves
both performance and fuel efficiency (not always true for gassers).

True, but boost levels in diesels inversely effect their reputation
for reliability.

As do boost levels in gasoline engines. However, turbo-normalization does
not usually impact reliability, if sufficient engine cooling is available at
altitude. Turbodiesels normally see about 10" of boost, and operate
reliably regardless of ambient pressure, as long as the turbocharger and
cooling system can cope.

SNIP

8. I can make biodiesel for 67 cents a gallon. You or I can buy
off-road
diesel or heating oil for much less than either auto gas, avgas or jet A.

Biodiesel gels at a higher temp than does winter diesel, and be damned
sure you have no rubber in the fuel system. And the 67 cents is
quoted for recycled oil. Not my first pick at altitude.

I fly mostly in the southern US in the spring, summer, and fall. If temps
at altitude (or on the ground) were below safe limits for biodiesel, I would
choose another fuel. However, much like turbine engines do, diesels return
large quantities of warm fuel back to the fuel tanks in flight. Fuel temps
rarely drop to ambient temperature. I agree, however, that it isn't a risk
worth taking.

I've made fuel from waste oil, but my current supply is virgin oil that was
rejected as a food ingredient. Eight thousand gallons of it. It should
last a while.

9. For a given trip, less fuel is needed, both in volume and weight.
25%
to 35%, depending on the trip profile. If the diesel is turbocharged and
gasser is not, the diesel's ability to cruise significantly higher may
result in a bigger efficiency spread.

This is dependent on tuning the boost map, and whether the blower is
big enough. Off the shelf this may or may not be true. I have not read
flight tests for any new European diesels which have been impressive
in high altitude performance. I doubt this is because of any
fundemental flaws, but rather performance tuning.

Agreed. Cooling is also an issue. Even with liquid cooling, thin air at
altitude may limit the installation's ability to shed waste heat.
Turbocharged gas engines face the same problem. However, several
manufacturers have produced piston aircraft capable of sustained cruising
in the lower Flight Levels. Diesels theoretically produce a bit less waste
heat than gasoline engines. It would be interesting to experiment with one.

SNIP

I dig your enthusiasm. Please post if you hear of any new diesel/
biodiesel aviation projects. I would be interested in reading any
related results. I believe that the new generation of diesels are the
long term solution for keeping GA operating costs down. But it will
take a while.

-Matt

The SmartCar aluminum diesel engine and the Toyota Yaris engine (Europe,
aluminum diesel) might be good candidates for small aircraft. However, this
Subaru seems to be an ideal candidate since its power and weight specs fit
so many available airframes. PRSUs are also available. I suspect we will
see these engines installed fairly quickly in European experimentals.

DS