Actually Paul, what I wanted to get to in this context was some
discussion as to whether or not the rotary could ever be developed into
an effective diesel. It would seem to have a problem achieving a
sufficiently high compression ratio for compression ignition. Perhaps it
could be started as a spark ignition engine, and once running and using
forced induction compression ignition could be possible.It would be very
nice to be able to fly on renewable vegetable oil fuel.
Is there any information available on diesel rotaries?
John Evans
Think logically and do things well. Think laterally and do things better.
Well yes that is a valid subject. The geometry of the rotary
does not allow high compression ratios required by true diesels.
As you reduce the depression in the rotor face to raise the compression
ratio the shape of the combustion chamber becomes less and
less favorable. Turbo charging or super charging mitigates
that somewhat as it packs more air into the
combustion chamber increasing the effective over all compression
ratio.
Rolls Royce built a compound rotary that had two parts.
The first part (which incidently just happened to be another
Wankel) was to raise the pressure of the air before
it was transfered to the power Wankel. As far as I know
RR never published the results but they did abandon the project.
These pics are not a real RR diesel engine but just a mockup.
Wankel Germany Gmbh built some small turbo charged direct high
pressure injection engines that would run on diesel fuel but they
were not true diesels. A spark plug ignited the mixture. IMHO it was
very difficult to get complete combustion so the BSFC and power
was nothing special.
Francois on here could update his progress as he is attempting
to do the same thing with the Mazda. Last I heard it was generating
75 HP running on diesel fuel and as I recall.
> Paul Lamar ...No rotor no motor.
John
As someone who is running several vehicles on biodiesel now and next summer
all lawn equipment on ethanol, flying on renewable is a given for me..
However ethanol seems to have the most advantageous in aviation presently
and especially with high compression engines.
Doug in Japan
Great topic. I have been VERY curious about the feasibility of diesel in a
rotary. The issues that were discussed are exactly as I would have guessed.
However, I have been running BioDiesel in my new Jetta since I bought it
two month and 4500 miles ago.
Paul, what do you see as the roadblocks to running our rotaries on ethanol
mix? It is still auto gas. True, I can't make it in my garage, like
BioDiesel, but, even though I am far from an envomentalwacko, I am for
logical choices and renewable fuels seems to be that. (on that note, I am
considering a bumper sticker on my Jetta.....Running on
BioDiesel.....flippin' the bird to OPEC on gallon at a time) FWIW.
All the best,
Chris
hopin' for our first start up by the new year...keeping our fingers crossed.
Christopher Barber
Attorney and Counselor at Law
"Serving the needs of Senior Texans"
Barber Law Firm
10827 Tower Bridge St.
Houston, Texas 77075-5032
281-464-LAWS (5297)
CBarber@TexasAttorney.net
www.TexasAttorney.net <http://www.texasattorney.net/>
Texas
<http://www.smileycentral.com/?partner=ZSzeb001>
--------------------------------------------------------
I really don't know anything about it. I have read a few things about it affects
on composite fuel tanks. Plenty of drag racers are running it in
their rotaries. I think the BTU's per gallon are down so range
may suffer.
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Here is something I found on the Internet.
"The amount of energy in a gallon of fuel is called its "energy content." For fuels,
the unit of energy most commonly used in the United States is a "Btu," which stands
for "British Thermal Unit." A Btu is the amount of energy that it takes to heat one
pound of water one degree Fahrenheit (or to raise the temperature of 1 cubic foot of
air 55 degrees Fahrenheit or to raise the temperature of 55 cubic feet of air 1
degree Fahrenheit).
So, the amount of energy in fuel is expressed in terms of "Btu."
Just as a can of "regular" soft drink has more calories than a can of "diet" soft
drink, so too does a gallon of diesel fuel have more Btus than a gallon of ethanol
fuel, methanol fuel, liquefied petroleum gas, liquefied natural gas, compressed
natural gas, or hydrogen (these are different types of clean alternative fuels).
The energy content of a gallon of gasoline ranges from about 109,000 to 125,000 Btu.
The average is about 114,000 Btu. The energy content of diesel fuel is between about
128,000 and 130,000 Btu per gallon (lower heating value).
If an alternate fuel has fewer Btus, your vehicle won't go as far (generally
speaking). So, to go the same distance, you have to use more gallons. This usually
means having a larger fuel tank. "
----------------------------
Looks like the range will be close to 60% as far on a tank of fuel.
You will also need much larger injectors. This is not much of a problem
for slow airplanes with thick wings but it gets to be a real problem
with fast airplanes that have thin wings. Small jets for example.
Slow airplanes usually have plenty of room for larger tanks. Maybe
not 1.7 times however.
I think Doug is planning on replacing the
back seats in his SeaWind with a huge fuel tank. I hope he does not
get drunk with the fumes :) This is the main reason for his interest
in turbo compound and a CS prop will help.
Paul Lamar ...No rotor no motor.
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