Gasahol Update

Corky Scott wrote:

Well I do, I was an auto mechanic with gas started being laced with
alcohol, and saw the results several times.

Oh, I saw the results. What I meant was that I do not remember what it was in
those hoses and such that was affected by exposure to alcohol.

One of my friends was a line mechanic for an Oldmobile dealer. His stories were
similar to yours. I happened to own a Ford during that period, and my only
problems involved hoses in the fuel system. Our other car was an Opel, but it
would only run on Amoco high test, so we never had an alcohol-related problem
with it.

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.

On model airplanes using methanol based fuel, they use silicone fuel
tubing. With gas engines you use tygon or neoprene tubing. The
alcohol will make those tubings harden and crack withen a few weeks.
But not the swelling and turning to liquid. That has to be from a more
active solvent such as toulene or acetone.

Sport Pilot wrote:
On model airplanes using methanol based fuel, they use silicone fuel
tubing. With gas engines you use tygon or neoprene tubing. The
alcohol will make those tubings harden and crack withen a few weeks.
But not the swelling and turning to liquid. That has to be from a more
active solvent such as toulene or acetone.

Not so. I never used any additives in my cars, and I had problems with softening
and swelling of the hoses in the fuel system of my van. Besides, the gas in
Georgia and Tennessee (where I lived at the time) was cut with ethanol, not
methanol.

This was a very definite, well-documented problem at the time, and no amount of
theory based argument is going to change that fact.

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.

In article 6E0oe.883$qE2.219@trndny09,
George Patterson wrote:

Corky Scott wrote:

Well I do, I was an auto mechanic with gas started being laced with
alcohol, and saw the results several times.

Oh, I saw the results. What I meant was that I do not remember what it was in
those hoses and such that was affected by exposure to alcohol.

One of my friends was a line mechanic for an Oldmobile dealer. His stories
were
similar to yours. I happened to own a Ford during that period, and my only
problems involved hoses in the fuel system. Our other car was an Opel, but it
would only run on Amoco high test, so we never had an alcohol-related problem
with it.

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.


I have a book, "Aviation Fuels and their Effecton Engine Performance,"
dated 1953, by the Ethyl Corp. and supplied to the USAF (P.O.
AF-33(600)5312) and USN (Contract no. 52-202). In it they state that
hoses subjected to petroleum-based fuels will deteriorate when exposed
to paraffins or napthalene-based fuels; likewise, hoses that have been
subjected to paraffin or napthalene-based fuels will deteriorate when
exposed to petroleum-based fuels.

IOW, the hoses work well with either kind of fuel, but you will get into
trouble when you switch fuels. This phenomenon is exactly what happened
to autos when MTBE became widespread.

--
Remove _'s from email address to talk to me.

"Casey Wilson" N2310D @ gmail.com wrote

Additionally,
I found more than one company (B.F. Goodrich, for one example) that
manufactures elastomeric products specifically for use with alcohol(s).

Right, but airplanes, with their "slow to change" mentality, do not use
exclusively alcohol resistant seals and hoses.
--
Jim in NC

What does gasahol do to the
fuel system that is destructive?

Nobody has hard data. All fuel system tests have been with pure alcohol in
a lab beaker. Sort of like feeding rats 100% saccharin and then noting an
early rat demise.


For that matter, what damage does it do to
the engine?

None. As a matter of fact, it cleans the hell out of the upper end.



1) You will only get 95% of the engine's output power compared to pure
gasoline,

Yes, at 100% ethanol. What is the output power degradation at 5% ethanol
concentration? 0.05% or something like that.


2) Your fuel system elastomeric seals, diaphrams, floats etc are not
compatible with any substantial alcohol content,

Your source for the study and verifiable results, please?



3) The vapor pressure of the alcohol-laced fuel is higher,

Your source for the study and verifiable results, please?



4) The long term storage properties are horrible.

Certainly you must be kidding. I've got a bottle of Everclear that must be
30 years old and still has the same effect as the day I opened the bottle.
Alcohol has a MUCH better storage characteristic than gasoline.




Did I miss any?

Most all of them.


Jim

I agree it does no damage to the mechanical and valve portions of the
engine.

According to Marks Engr Handbook, the heating value of an equal mass of
10% ethanol gasahol is 96.1% of an equal mass of gasoline (I used
Hexane as an approximation to gasoline & assumed ethanol). Here in MN
the car mileage reduction is generally assumed to be about 5%. I see
that in the differences between Wisconsin gasoline vs Minnesota gasahol
in my vehicles.

Since the fuel mass flow in an aircraft carb isn't likely to change
significantly, and since the engine is a heat engine, with all other
things being equal, a power reduction is to be expected. Other items
such as compression ratio, timing, mixture proportions etc could be
varied to optimize the use of gasahol, but the heat value just isn't
there.

Who knows what the seals etc used in an aircraft are - except that
there are a lot of legal reasons that they are not being updated in
contrast to technical reasons why they should be updated. Actually a
simple aircraft engine has few seals as you know, and if the float
(let's see we're back to metal again aren't we) don't sink, and the tip
of the needle doesn't dissolve, we are back to mostly static seals in
the fuel selector etc. I don't know about fuel cell bladders, except
that given the regulatory climate, there is a good chance they have not
been updated for 50 years either.

I just had the seals go and the idle jet varnish over in my '87 Yamaha
M/C carb, and lawn mowers here routinely need carb work.

Vapor pressure is primarily determined by fuel temperature, although a
standard temperature is used for the Reid vapor pressure test. But
that standard temp has to be held very closely to make equivalent fuel
evaluations. In practical service the significance of the temperature
variation seems to never be addressed. For example, where is it
written that you can't paint your wings black? A chem prof once noted
that the vapor pressure typically doubles every 15 deg F.

I have to agree that only in a most marginal situation (probably
aggravated by the need for a fuel pump) might ethanol (b.p. = 172 deg
F) or especially methanol (b.p. = 148 deg F) put you over the edge into
trouble. My original response was hearsay.

The long term storage issue - the weed whip (manual) I just bought says
to throw away all ethanol laced gasoline after 60 days.

I agree booze keeps a lot better but that is primarily an alcohol/water
& flavor mix which does not seem to be subject to deterioration (maybe
shrinkage?) of alcohol hydroicarbon mixes.

Old sour gas is a problem here in MN. It seems to be aggravated by
higher fuel storage temperatures. My small-engine repairman neighbor
confirms this (as well as the rampant carb problems).

You would have more power from ethanol if you richen up the mixture.
But I doubt less than 5% ethanol is enough to matter either way.

Yes - I would think a richer mixture would be necessary to
theoretically get to the 96.1% power level with gasahol. That the
mixture has already been optimized for gasoline would make me expect an
even greater power reduction for gasahol. Actually, there are many
things that affect the mixture distribution more in an engine that the
improvement of a mixture shift would be pretty insignificant.

The accuracy of the mixture control and distribution in smaller and
older aircraft is pretty mediocre by any modern EFI standard.

No, if you richen up the mixture the gasahol will actually give more
horsepower and better climb, performance etc. But with more fuel
consumption. Alcohol has oxygen in the fuel. Although it has less BTU
per pound or gallon, if you richen it up to the highest RPM it will be
much richer than gasoline, and more BTU per hour.