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

...



"Morgans" wrote in message
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"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


Why any sort of reciprocating engine?...small turboprops would be the best solution of they can get the mass fuel flow
problems resolved...