"ventus2" wrote in message
...
Not wanting to restart the previous discussion on how ethanol is made and
how much is in which fuel, available where, the question I am interested
in
is; does anyone know what effects ethanol will have on:
tanks - metal / composite
fuel systems - tubing/electric pumps/carbys
Engine - serviceability issues/foreseeable maintenance conerns

The EAA is obviously concerned about ethanol in aviation fuel otherwise
they
would not have fought the introduction(according to the EAA mag). This is
defintiely a concern for all aviators, not just the US.

If there is going to be 'no option' in the future (other than running on
Avgas or Diesel), then we need to start educating the masses on what
effects
it will have, especially the home maintainers.

I understand that ethanol will degrade some resins, which could throw a
spanner in the works for the wet wings like the Jabiru. Though it could
just
as likely eat away at sloshing compounds etc.

Cheers
Chris


I am not really sure whether or not I want to either, because I believe that
it really is four issues in one. I am going to list all four; but I
strongly believe that the third and fourth are the most important:
1) Ethanol and Methanol, as well as other "oxigenators", when used in
high concentrations, affect different materials in different ways than
"pure" gasoline manufactured in accordance with the appropriate
specification. That's a lot of mumbo-jumbo to say that they are chemically
different, and I am not a chemist either...
2) Ethanol and Methanol are hydroscopic. The most obvious is that you
can not drain water out of the fuel. The good new is that a small amount of
water in the blended fuel won't cause a complete loss of power, although it
will cause a power reduction. A small amount of alcohol, or a large amount
of blended fuel, can also be added to absorb the last traces of water which
might be present after sumping the tanks. I believe that is how "Prist"
works, and I already know that it is not approved for gasoline powered
aircraft engines.
3) According to the EAA web site, the "autofuel" STC permits the use of
fuel conforming to ASTM Specification D-4814 and/or D-439. Oxigenated fuels
and do not conform. Therefore, I presume, in order for oxigeated fuels to
be approved, the entire STC certification program would have to be
duplicated with oxigenated fuels. That might be required for each
"oxigenate".
For information regarding the current STC, see:
http://www.eaa.org/education/fuel/stc.html
4) Fuel is ordinarily taxed "at the pump" based on where it is purchased;
so that, even though there is no such thing as untaxed fuel, it is possible
to pay the taxes into the wrong account. Therefore, if you buy gasoline at
your local marina or automotive filling station, and then truck it to the
airport for your airplane, you are probably adding the wrong kind of fuel to
the debate over user fees!

The issue not mentioned above, because it is not part of the alcohol issue,
is that the original purpose of the STC program was to make 80 octane fuel
available to all aircraft operators. Engines operated on higher octane fuel
than that which is required run hotter, require more maintenance, and are
more subject to fouling. That is not a good combination, so there was a
clear need which still exists.

Peter