100 Low Lead availability - cont.

There are various possibilities but none are likely to be as good as 100LL
and all will be costly. It nonetheless seems like a good time to start
thinking about the options in a post 100LL world.

It's true that much more ethanol than 100LL is required so even if it's
cheaper per gallon, the cost per engine hour is likely to be nearly the
same - maybe even higher. I really don't think ethanol is a workable
solution for those who want to fly their airplanes cross country. That
probably means AGE85 fuel pumps will be rare so if you want to take your tug
to an encampment, you may have to bring along your own fuel supply.

As for carburetors and ethanol, there seems to be some disagreement. The
AGE85 (Aviation Grade Ethanol 85% See: http://www.age85.org/ ) people say
that carburetors at full rich provide a stochimetric fuel/air ratio at sea
level and that's good enough. Other's say that the old Marvel Schrieber
carburetors can't work with ethanol due to the fuel passages being too small
for the additional 40% fuel flow that ethanol requires. It makes me
nervious to think of being lean of peak EGT for a sea level takeoff so I
tend to agree with the detractors. Still, it might work for operation at
high altitudes.

Fuel injection is easier since there are fewer elastomer seals in the system
and you only need to select injectors with 40% greater fuel flow.

As for MOGAS, any STC will specify exactly what fuel is allowed but the
stuff at the nearest pump is not likely to match the STC. Every state and
locality seems to have laws specifying a different fuel blend. That makes
MOGAS problematic.

Higher compression ratios are allowed with ethanol since it has an octane
equivalent of about 115 - 145. Higher compression + some ignition advance
recovers some of the fuel economy lost to the lower energy content.

Bill D


"BT" wrote in message
...
Bill.. our STC to bump the O-540 from 235HP to 250HP with a piston change
negates the autofuel STC.. 100LL required.
That STC would also need to be reworked or the STC to allow the IO-540 to
use Ethanol would need to include the option for higher HP.

Current auto engines that are "flex" fuel can burn regular auto low lead
or E-85 fuels. The E-85 fuel is cheaper than standard fuel, but the
resulting mpg is lower, the E-85 is less efficient and your total dollars
spent to complete the same work (travel the same distance) is higher with
more fuel stops.

BT

"Bill Daniels" bildan@comcast-dot-net wrote in message
...

"Mike Schumann" wrote in message
.. .
I can't imagine that happening. Until there is a replacement for 100LL,
with the number of aircraft flying in the US, there will be a supply from
somewhere. The big question will be the cost.

Mike Schumann

The volume of fuel consumed by the US piston fleet is miniscule - less
than 1% of all gasoline production and thus doesn't even appear on the
radar of fuel producers. I think the idea that "supply will meet demand"
is a risky one. As far as they are concerned, anything less than 1% is
no demand at all. The liabilities involved in handling TEL far outweigh
potential profits.

I think we are in the last stages of an economic "death spiral" for
AVGAS. High prices mean lower demand. Lower demand means higher price
per gallon since fixed overhead is spread over fewer gallons. Still
higher prices further reduces demand. In effect, it's "economies of
scale" working in reverse.

However, there may be hope. See:
http://www3.baylor.edu/bias/publicat...ayaircraft.pdf

This paper describes obtaining an STC for operating a Pawnee on ethanol.
Note that the engine described is the fuel injected Lycoming IO-540 and
not the more common carburated O-540.

Nonetheless, given enough money, it's possible to convert a O-540 to fuel
injection since the injector bosses are cast into the cylinder heads -
one need only drill them for injectors. Converting a fuel injected
engine to ethanol is relatively easy. The modifications required to use
ethanol with a carburator are not really feasable.

Note the large increase in fuel consumption - ~40%. This probably
eliminates ethanol as a fuel for long range cross country airplanes but
for "fixed point" operators like crop dusters and glider towing
operations, it's a PITA but workable.

The total modifications required would be to convert the O-540 to fuel
injection using injectors suitable for ethanol and, since the cylinders
have to be removed anyway, it would be desirable to replace the pistons
to achieve a higher compression ratio. If it were desired to keep
refueling stops to the same intervals as with AVGAS, larger tanks would
be needed.

The downside is that the conversion will be costly. The upside is that
we maintain the availability of aero tows, we get more performance from
the Pawnee and, possibly, greater engine life due to cooler running
cylinders.

Bill Daniels





"Bill Daniels" bildan@comcast-dot-net wrote in message
. ..

"Dave Newill" wrote in message
...
On Mar 4, 12:32 am, "Mike Schumann" mike-nos...@traditions-
nospam.com wrote:
They will keep making TEL untill it is no longer profitable.

I visited GAMA headquarters to understand the situation on AvGAs from
their expert. He said that the tanker (ship) that carries the TEL will
be decommissioned in a few years - that will not stop it from being
shipped from its source (Russia) as it will simply be put into triple
walled sea-tainers - but the amount shipped each time will be smaller
and the insurance - as it is being shipped with other goods - will be
higher.

It will not go away - but it will be very expensive -however there is
so little of it in the fuel that it thankfully does not take much.
Also note that it is not shipped by pipeline - must be shipped by
truck so as not to pollute the pipes! Finally, there is a Friends of
the Earth petition getting hearing in congress to remove lead from all
fuels - if you think we have problems - think about all those outboard
motors out there!



The only producer of TEL is the Octane Additives Division of Innospec
(formerly Octel) - A UK based company. I believe, but can't find
referencable sources, that the actual TEL production is at a plant near
Madras, India. I have found no references to Russian production.

From reading press releases in financial publications, it appears that
revenue and profitability of the OA division is in a steep decline
(50%/year). The parent company is loading accounting charges onto the
Octane Additives Division in the form of "Goodwill Impairments". They
are also making statements to the effect that the future business of
the division will be "environmental remediation activities". The
company is now accepting bids in India for the dismantling and desposal
of the worlds only TEL tanker ship. This looks like an imminent
shutdown of TEL production.

I did find a comment that there is a six months supply of TEL in the
US. It appears to a casual reader that the end for TEL may indeed very
near.

Bill D






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