On Thu, 12 Jun 2008 09:43:50 -0400, "Peter Dohm"
wrote:

"Dick" wrote in message
news:S084k.10872$kW2.67@trnddc01...
Recently my gas station placed stickers on the pumps warning it could
contain up to 10% ethanol.

My ride is an experimental built in 1997 with a C-85 always run on mogas.

Quick research indicates 3 concerns:
1-loosens debris inside the fuel system affecting filters.
2-mixes more readily with water (hydroscopic) but can experience "phase
separation" during climbs causing water to overload filter/sediment bowls.
3-can deteriorate composites, rubbers and plastics causing
leaks/breakages.


Leaning towards more frequent gascolator inspections for 1 and 3, but
unsure on overloading a sediment bowl....

I'm wondering how others are addressing these concerns.

Thanks, Dick

I am not flying at the present time, and I am really annoyed by the entire
"gasohol" farce.

(Brief Rant)
E-10 is a more expensive product, contains as little as 96 percent of the
energy, is generally regarded as less stable, and is the result of purely
political decisions of questionable merit!
(End of Brief Rant)

OTOH, since it is an experimental and you have been using MoGas all along,
you are more likely to know what materials are in the fuel system--if it was
mine and the problem was the tanks, I would switch immediately to AvGas and
avoid idling with rich mixture during warmup and taxiing.

Some assistance regarding the hoses, seals, and gakets may be as close as:
1) The auto parts store--those guys have been on the "front lines" a lot
longer, or
2) The nearest hose and o-ring suppliers for aircraft--who probably have
product data sheets for what the sell.

This is the first that I remember hearing of "phase separation" which may
just mean that I forgot. However, there is at least one obvious way to
test. Get something that can produce a good suction--a "feeding syringe"
from the nearest feed store might be a good choice. Then, put some E-10
gasohol in a clear glass soda bottle, connect the bottle to the feed syringe
with a sturdy hose (or something similar), pull back on the plunger, and see
what happens. That should give you a way to take your fuel sample from
about sea level to about 18000 feet in a hurry. Obviously, you would need
to add some instruments and test at various temperatures to learn what might
happen over a wide range of temperatures and altitudes; but a lot of us
bloviate a lot on usenet and, with some very simple testing, you should be
able to get an idea of whether the whole discussion really applies to your
application.

Peter

P.S.: A home brew test for the actual presence of ethanol was discussed
on this forum a few months ago.

Phase separation is temperature dependent.
If the water content of the fuel is borderline at 70F and you go up
3000 feet the 54F temperature may cause the water and ethanol to drop
out.
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