> Paul,
>
> It is not correct that range has to suffer by burning
ethanol. In
> fact range can increase if you fly above 10,000 ft density
altitude.
>
> The reason is that ethanol has an oxygen content of about 25
> percent. The effect is like supercharging, or nitrous oxide, or
> dragsters that use nitromethane which has huge amounts of oxygen.
> Gordon
Sorry, this is not correct -- the oxygen in ethanol is
representative of
the fact that is has been partially oxidized, in other words,
partially
burned. So some of the energy content has been expended over being a
hydrocarbon. Nitromethane is a different story. The oxygen can
come free
of the nitro-groups and combine with any available hydrocarbons.
You carry less energy per pound with ethanol, how you use it
determines
your specific fuel consumption, milage, etc.
The evaporative cooling effects and octane effects are real, but
the
oxygen content has already been used up ( i.e. not available).
Bill Schertz
Bill,
Thanks for that insight.
What exactly do you mean by, "partially oxidized?" The way I
understand it pure ethanol has an oxygen content of 35 percent, so
all of that oxygen should be available for oxidization, no? (AGE 85
is only 85 percent ethanol -- the rest is pentane isomerate -- so
its oxygen content is about 30 percent.)
The oxygen is the reason the stoichiometric air-fuel ratio of
ethanol is lower than gosoline -- because when you add the same
volume of air, there is more total oxygen due to the oxygen
embedded
in the fuel, so you need more fuel to completely oxidize the extra
oxygen. See the attached table, "Ethanol Gasoline Properties."
The heat energy of ethanol per pound or per gallon is lower than
gasoline, as you pointed out. However, the oxygen in the ethanol
results in better thermodynamic efficiency, so power actually goes
up. You can see in the attached chart that an O-470 engine running
on AGE85 has 15 percent more peak power.
The graphic on flight test data shows that at 10,000 feet a Mooney
with an IO-360 running AGE85 has a fuel burn at lean mixture that is
less than the same plane on avgas at 8,000 feet. One of the
advantages of ethanol is that very lean mixtures can be safely run.
Regards,
Gordon.
Gordon,
What adverse effects are there on housings when you use Ethanol
? I had
developed and manfactred seals which resist methanol and future long
life oil detergints. These could be used on a rotary engines too,
however I had the impletion that Ethanol, Methanol etc corrod the
housing.
regards
Roderick
Roderick,
As far as I can find from the literature, AGE 85 is compatible with
existing fuel system materials.
Here are some snippets from I think Baylor University which has
lots
of info on AGE 85.
Regards,
Gordon.
Gordon,
While I'm sure the info you provided about operation at 10K and
above
is true, I must interject that most of my local flights would be
over
before
I even got to 10K feet! Lots of local fun flying never exceeds 4K.
One other item that is rotary specific, does anybody know if there
may be
mixing trouble if you run fuel/oil mix? I'm NOT stating this, I
don't know.
I'm not a chemist and I don't even play one on TV.
Bill Jepson
Bill,
That's a good point about the oil mixing, and that has crossed my
mind too. I don't have an answer for that, but the literature says
that AGE 85 mixes seamlessly with 100 LL, in whatever ratio you
like. Based on that I would guess that oil should not be a problem.
Another hint is that AGE 85 actually contains about 1 percent
biodiesel, so oil mixing should not be a problem. But that is far
from a fact at this point.
I'm going to attach a power point presentation that gives a very
good intro to AGE 85. I think it's available from the Baylor
website.
Regards,
Gordon.
What is the cost per gallon ?
Roderick Scotto
The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site.
http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.