Gasahol Update

"Newps" wrote in message
...


Jay Honeck wrote:
But
you bring up a good point. How does one tell just what you are getting
when you put in mogas or avgas?


If there are no visible contaminants, there is no water evident, and it
smells like gasoline, I run with it -- and unless you have some sort of
a chemical laboratory in your hangar, there's not much else you can do.

Like so many other things in this world, it's really not worth the
effort to worry about.

Me too. If it smells like it might burn I'll use it.

And that's more than enough of a scientific test for the older low
compression engines They were designed for fuel without lead and octanes in
the mid to low 70s.

Todd Pattist wrote, "... find empty clear bottle (typically a water bottle),
scratch mark at about 10% point near bottom, fill with water to that point,
add gas, shake, let settle, see if the water level is higher. If it is,
alcohol has moved from the gas to the water."


I have a small fuel sampler named "Fuel-Check by Daansen." It is designed to
measure the amount of alcohol -- from 0 to 30% -- dissolved in a fuel
sample. The sampler is first filled with water up to the "water" line, which
is about an inch up from the bottom. The water line is also the 0% alcohol
line. The sampler is then filled with fuel to the "gas" line, which is about
3 1/2 inches up from the bottom. The percent of alcohol is then read on the
"% alcohol" scale which runs from 0 at the bottom to 30% about 3/4 inch up
from the 0 line. Thus it appears that if there is alcohol in the fuel it
will dissolve in the water and raise the water/alcohol level.

George Patterson wrote:

No, he got it exactly right. The alcohol will come out of solution with
the gasoline and mix with the water. The effect is that it appears that
the water level rises.

The explanation is pretty simple. In un-scientific words:

- Water and gas don't mix.
- Alcohol mixes with both water and gas.
- Given the choice, alcohol prefers water over gas.

Stefan

In article .com, Doug wrote:
engine. Also, keep in mind car gas is NO LEAD. Lead has lubrication and
cushioning properties. I know people complain about the lead deposits
on their spark plugs...

Oh, on our C-85 engine, we never got fouled plugs from 100LL, just stuck
valves, which is a bit more worrying at 250' AGL and no remaining
runway!


--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

Hmm,
But water will mix into a mixture of gas and alcohol. Maybe that
only works with less water or it takes some agitation. This is how gas
deicer works. The alcohol melts the ice and allows the water to
desolve into the gas alcohol mixture.

In rec.aviation.owning Sport Pilot wrote:
Hmm,
But water will mix into a mixture of gas and alcohol. Maybe that
only works with less water or it takes some agitation. This is how gas
deicer works. The alcohol melts the ice and allows the water to
desolve into the gas alcohol mixture.

But what?

Water is only very slightly soluable in gasoline; basically not at all.

Water is totally soluable in alcohol.

Alcohol is moderately soluable in gasoline, that is, up to a limit.

Where is the confusion?

--
Jim Pennino

Remove .spam.sux to reply.

wrote:
In rec.aviation.owning Sport Pilot wrote:
Hmm,
But water will mix into a mixture of gas and alcohol. Maybe that
only works with less water or it takes some agitation. This is how gas
deicer works. The alcohol melts the ice and allows the water to
desolve into the gas alcohol mixture.

But what?

Water is only very slightly soluable in gasoline; basically not at all.

Water is totally soluable in alcohol.

Alcohol is moderately soluable in gasoline, that is, up to a limit.

Where is the confusion?

--
Jim Pennino

Remove .spam.sux to reply.

Alcohol is completly soluable in gasoline, in fact adding a small
amount of gasoline to model airplane fuel is sometimes done to improve
starting and increase engine heat during the winter. The confusion is
that you can also mix water gas and alcohol and have the three
completely disolve. So why didn't the water disolve into the gas and
alcohol mixture?

Has anybody verfied that this method works all the time? I have a
hunch the rusults can vary depending on vibration and temperature.

T o d d P a t t i s t wrote:
"Sport Pilot" wrote:

Alcohol is completly soluable in gasoline, in fact adding a small
amount of gasoline to model airplane fuel is sometimes done to improve
starting and increase engine heat during the winter. The confusion is
that you can also mix water gas and alcohol and have the three
completely disolve. So why didn't the water disolve into the gas and
alcohol mixture?

A typical gasoline-alcohol automotive fuel blend can
dissolve water up to only about 0.6 or 0.7% at 70=B0F. Beyond
this the water forms a separate layer and the alcohol
preferably is dissolved in that layer.

Has anybody verfied that this method works all the time? I have a
hunch the rusults can vary depending on vibration and temperature.

If the maximum 0.6 or 0.7% water/gas/ethanol blend at 70=B0F
is cooled, both the water and some of the ethanol become
insoluble in the gas. The result is two layers of liquid -
an upper ethanol-deficient gasoline layer and a lower
ethanol-rich (about 75% ethanol) water layer. If more water
is added, the lower layer of water increases in volume and
continues to preferentially dissolve the ethanol.

The test method uses 10% water, far more than the maximum
that can be dissolved in the gas/ethanol blend, so it always
forms two layers and sucks the alcohol out of the gas.


Do not spin this aircraft. If the aircraft does enter a spin it will retu=
rn to earth without further attention on the part of the aeronaut.

(first handbook issued with the Curtis-Wright flyer)

I have done some research also, alcohol is NOT completly soluble in
gasoline, it varies with temperature and gasoline composition. It is
especially not soluble in cold weather. The reason the gas disolves in
model airplane fuel is that the castor oil is soluble in both methanol
and gasoline.

But the basic fundamental questions remains despite the discussion of how
much water will dissolve the alcohol on the head of a pin...

The EAA STC says that there can be NO alcohol in the gasoline (and that is
theoretically impossible -- PPB will always be there)

but

The EAA web page gives instructions on gasahol up to 5% alcohol and how to
safely burn it.


Doesn't anybody get the contradiction and what it might mean to the real
world -- especially in California where the state mandates 5.x% in the
gasoline, no more and no less?

Jim

T o d d P a t t i s t wrote:
"Sport Pilot" wrote:


Alcohol is completly soluable in gasoline, in fact adding a small
amount of gasoline to model airplane fuel is sometimes done to improve
starting and increase engine heat during the winter. The confusion is
that you can also mix water gas and alcohol and have the three
completely disolve. So why didn't the water disolve into the gas and
alcohol mixture?


A typical gasoline-alcohol automotive fuel blend can
dissolve water up to only about 0.6 or 0.7% at 70°F. Beyond
this the water forms a separate layer and the alcohol
preferably is dissolved in that layer.


Has anybody verfied that this method works all the time? I have a
hunch the rusults can vary depending on vibration and temperature.


If the maximum 0.6 or 0.7% water/gas/ethanol blend at 70°F
is cooled, both the water and some of the ethanol become
insoluble in the gas. The result is two layers of liquid -
an upper ethanol-deficient gasoline layer and a lower
ethanol-rich (about 75% ethanol) water layer. If more water
is added, the lower layer of water increases in volume and
continues to preferentially dissolve the ethanol.

The test method uses 10% water, far more than the maximum
that can be dissolved in the gas/ethanol blend, so it always
forms two layers and sucks the alcohol out of the gas.


Do not spin this aircraft. If the aircraft does enter a spin it will return to earth without further attention on the part of the aeronaut.

(first handbook issued with the Curtis-Wright flyer)


Todd,

So what your saying is that if you have ethanol rich gasoline, just add
water and shake and what your left with is gasoline without ethanol.

Sounds like a good way to purify gasoline.

Dave