Mailing List flyrotary@lancaironline.net Message #48968
From: Bill Monroe <aviator@stinsonvoyager.com>
Subject: RE: [FlyRotary] Re: FW: Fuel Filter \ Ethanol
Date: Fri, 6 Nov 2009 06:33:09 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
I think it would be great to stick to technical, on-topic discussions.



-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Ernest Christley
Sent: Friday, November 06, 2009 6:27 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: FW: Fuel Filter \ Ethanol

Steve Thomas wrote:
>
> Here is an update on the gasohol tests that I have been
> running. The witness samples that I have put into the test
> jars are all from either my own or the original factory
> layups, all using Derakane 411 of some sort. I used the -
> 45 for a long time, but switched to -350 sometime later
> as it was easier to get and wetted out better. I have three
> tests running as noted below:
>
> 1. The first test is with two samples in a jar with Jose
> Cuervo. Jose Cuervo is 40% ethanol. I have an original
What a terrible waste of perfectly drinkable Jose Cuervo.

I took the time to learn to weld aluminum and switched from the plans
directions of a fiberglass tank to use an aluminum tank. The issue that
concerned me most, and I really hope people using glass tanks will heed
this closely, the most pressing issue is not ethanol (today's
additive).  The most pressing issue is, "What will the clueless
politicians mandate that we add to our fuel in the future?"

You hope for the airplane to be flying in 20yrs.  The government has
clearly demonstrated that they are willing to go along with any
boondoggle, no matter how much it harms the people they are claiming to
help, as long as the right campaigns get a properly sized donation.  
Ethanol in gasoline is ridiculous by any reasonable measure, except for
how much it enriches Monsanto and ADM;  yet, there it is (and is
increasing).  There is absolutely no way to know what bright idea they
will come up with in the future.

The epoxies we use in our structures is an organic compound, which will
have a measurable reaction to any organic solvents.  All carbon based
liquid fuels are organic solvents.  Different types of epoxies will have
different reactions with different solvents.  There isn't a universal
solvent, and epoxy that stands up well to the first, will melt in the
second, while a different epoxy formulation will turn to goo by the
second and seem to ignore the first.  Someone has a rulebook somewhere
that gives guidelines as to what solvents will affect which epoxies.  I
have only seen pieces of it, but I know enough to know that the rules
are long, complicated, and hideously complex.  People make careers of
specializations within specializations within the various fields of
organic chemistry, fer chrissakes.

So, we have an unknown future where clueless politicians get lobbied to
mandate we pour various amounts of random chemicals into our fuel
supply.  You have fuel tanks built with organic chemicals that WILL have
a reaction to these unknown chemicals, whether it be barely noticeable
or instantaneously turning the entire tank to goo.  You have a situation
where a slight reaction can clog a filter and result in fuel starvation
to the engine in flight, or a radical reaction resulting in the hangar
floor below years of work being covered in volatile fuel.  AAARRRGH!

If you're going to stay with aviation fuel, I'd say that you're
reasonably safe with hand-laid tanks.  The FAA is going to require a lot
of tests to meet STCs before they let just anyone change the formulas.  
That has been demonstrated.  We still have leaded fuel more than 30
years after it was mandated away everywhere else.

But IF you're going to be pouring gas from your local station into your
tanks, either commission a roto-moulded tank from the same materials
used to make plastic gas cans, or build one from aluminum.  All fuel
lines should be aluminum, or automobile approved materials (including
O-rings and such).  I'm not saying that going with the automobile gear
will be a complete shield from trouble, but the politicians are more
likely to fear millions of drivers being stranded when they push
chemicals that are incompatible with autos.

I'm not trying to disrespect your experiment, Steve.  In fact, I think
that it clearly illustrates the point that all these interactions are
funky, and not necessarily predictable.  The point that bothers me is
that they miss the most important point.  All you can test is last
week's/month's/year's formulation; but you will, by necessity, be flying
with tomorrows.

--
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