AVGAS 80 & MOGAS

Modesto CA still has legal mogas. THe catch is that they have to take it
8000 gallons at a time (full tanker load).

The alcohol is blended into the gasoline right at the tanker load spigot and
"mixed" with the tanker sloshing it all around on the trip to your local gas
station, so all they have to do is turn off the alcohol switch and the whole
damned load is alky free. But, as I said, you have to take a full tanker
load of it and most airports can't afford to do that.

Jim

--
"If you think you can, or think you can't, you're right."
--Henry Ford

"Robert M. Gary" wrote in message
ups.com...
On Oct 29, 6:31 pm, Helen wrote:
You need an STC. I have the EAA one.

I used to too. However, do you find many places that still has legal
autogas? In California it seems all the gas has the prohibited
ethanol. With the liberal states requiring ethanol to starve the
Mexicans from their tortillas and the midwester states requiring it to
boast their own pockets it doesn't seem like anyone is left with old
fashion, FAA approved, mogas.

-Robert

"RST Engineering" wrote

But, as I said, you have to take a full tanker load of it and most
airports can't afford to do that.

Are they allowed to have two or three airports share a full load?
--
Jim in NC

Dunno.

Jim

--
"If you think you can, or think you can't, you're right."
--Henry Ford

"Morgans" wrote in message
...

"RST Engineering" wrote

But, as I said, you have to take a full tanker load of it and most
airports can't afford to do that.

Are they allowed to have two or three airports share a full load?
--
Jim in NC

"Robert M. Gary" wrote in message oups.com...
On Oct 29, 1:42 pm, Dallas wrote:
My C150M POH shows an approved fuel grade includes AVGAS 80.

Assuming you could find 80, how safe is it to run?

And, what are the modifications made to the fuel system to run MOGAS?

On a purely theoretical level, what would be the ramifications of fueling
up an unmodified Cessna 150 with 92 octane MOGAS?

--
Dallas

Depending on where you live MOGAS may not be approved. Only certain
blends of MOGAS are approved by the FAA and many communities restrict
those blends. .


Only if the airplane has the STC. If no STC, mogas is not approved...

In article ,
"Blueskies" wrote:

"Robert M. Gary" wrote in message
oups.com...
On Oct 29, 1:42 pm, Dallas wrote:
My C150M POH shows an approved fuel grade includes AVGAS 80.

Assuming you could find 80, how safe is it to run?

And, what are the modifications made to the fuel system to run MOGAS?

On a purely theoretical level, what would be the ramifications of fueling
up an unmodified Cessna 150 with 92 octane MOGAS?

--
Dallas

Depending on where you live MOGAS may not be approved. Only certain
blends of MOGAS are approved by the FAA and many communities restrict
those blends. .


Only if the airplane has the STC. If no STC, mogas is not approved...

There are two STCs involved:
1. Engine STC, verifying that the engine in question can safely run on
it.

2. The installation STC, which verifies that you will not get vapor lock.
In this case, a gravity-fed system has a major advantage.
For more than a one-off approval, you have to load the tank with 110F
fuel and climb to 10,000 feet to prove tha no vapor lock problems are
there. Sometimes an additional boost pump is required.

On Oct 30, 3:31 am, Helen wrote:
Cessna Pilots Associate actually recommends a
mixture of 100LL and AvGas for O200 and O300 engines after break in as
it better approximates the 80 Octane these engines were designed for
that the 100LL you are probably using. It will reduce your fowling
problems and stuck valves, and you won't need to run MMO.

We used to do that with our flight training airplanes. 75% mogas
and 25% 100LL to approximate the lead content of the old 80/87. But it
didn't work. We had sticking valves and worn valve guides. After we
went to straight 100LL the problems disappeared and we got plug
fouling instead, but that's a lot more manageable than top overhauls
halfway to TBO.
Unleaded mogas today is made differently than the leaded stuff was
years ago. Instead of boiling the crude and condensing the various
fractions at the different temperatures to get the fractions needed to
mix a batch of fuel, they disassemble the stuff on the molecular level
with catalysts or something and reassemble it into unleaded mogas. The
result is something rather different than leaded gasoline and some
engine components don't like it. Too "dry" or something. A major
rebuilder we deal with says they encounter considerable wear in
mogassed engines.
That's how I understand it, anyway. Some folks use mogas
exclusively and seem to have no trouble. We couldn't stick with it.

Dan

Sorry, that's an OWT. 80/87 had a MAXIMUM of 0.5 ml TEL per gallon. In
fact, due to the cost of the TEL and the ease of refining 80 octane gas
after WWII, 80 had zero lead.

Jim



We used to do that with our flight training airplanes. 75% mogas
and 25% 100LL to approximate the lead content of the old 80/87. But it
didn't work. We had sticking valves and worn valve guides.

Jim

Most tankers have multiple tanks. For example a 8000 gallon tank truck
could have four 2000 gallon tanks. This lets them deliver smaller
amounts of gas to the small Stop & Go type stores that don't want to
invest the dollars in a full load all at one time.

The multiple tanker layout is also a safety feature so that if one
tank starts a leak only part of the load will get out (small possible
fire and clean up and less money lost). Also it lets the tanker carry
different grades of gas (reg, super, extra $ super) on one delivery to
a station.

So, I see no problem (from experience a number of years ago in the gas
business) of dropping less than the full tanker at different
locations.

Only thing might be cost of tanker charge for the extra distance and
time needed to hit several locations??? Also it assumes that several
airports all needed gas at same time so one tanker could hit them all
with the total load of 8000 gallons.

Have a nice day in the land of F's & N's. Only spent 7 wonderful years
flying out there before SF went to the 'F's' )

Big John

************************************************** ***********


On Tue, 30 Oct 2007 15:50:50 -0700, "RST Engineering"
wrote:

Dunno.

Jim

"Big John" wrote

Most tankers have multiple tanks. For example a 8000 gallon tank truck
could have four 2000 gallon tanks. This lets them deliver smaller
amounts of gas to the small Stop & Go type stores that don't want to
invest the dollars in a full load all at one time.

The multiple tanker layout is also a safety feature so that if one
tank starts a leak only part of the load will get out (small possible
fire and clean up and less money lost). Also it lets the tanker carry
different grades of gas (reg, super, extra $ super) on one delivery to
a station.

Also, it is VERY important to have dividers in a large tanker, so when you
are putzing about with a third of a load, that you don't have the whole load
shift to the front at one time, or back, or whatever.
--
Jim in NC

Morgans wrote:


Also, it is VERY important to have dividers in a large tanker, so when you
are putzing about with a third of a load, that you don't have the whole load
shift to the front at one time, or back, or whatever.

The tanks will have baffles in ADDITION to the tank segregation. Even
2000 gallons is more than you want to slosh around uncontrolled.