AVGAS 80 & MOGAS

----- Original Message -----
From: "Jay Honeck"
Newsgroups: rec.aviation.piloting
Sent: Tuesday, October 30, 2007 10:22 AM
Subject: AVGAS 80 & MOGAS



No problem getting unpolluted, ethanol free gas here in Iowa,
ironically the source of most ethanol.



Yep.....Jay, every time I think about the corn states exporting their lousy
fuel to other states, and not using it locally, it tics me off. I put over
1500 hours on a Lyc with a Peterson STC, and that was the best fuel for that
engine.....bar none. The plugs were clean, the oil remained clean 2-3 times
longer etc. But alas....now mogas in our area all has alcohol, so now I
clean plugs and change oil more often......and of course pay the higher
price for 100LL. Oh well...

John Severyn
@KLVK Livermore, Ca.

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

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.

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?


Low compression engines work well on 80 octane. The problem with 100LL
is that you don't need the extra octane (does nothing for you) but you
also don't want all the extra lead. 100LL is only "low" in lead
compared to the old 100/130 fuel it replaced. It has 4 times the lead
that 80 did and way more than premium auto gas ever did.

The only problem is the corn lobby is making it pretty darned difficult
to find autofuel without ethanol in it and ethanol is not approved for
the autofuel STC's (and it plays hell on us boaters too!)

Back in the 1980's when I still had my 1941 T-Craft (which had an A-65
and ran fine on the leaded regular mogas which was still available at
a few stations then), I looked at the type certificate and all it said
was "73 octane minimum". Never was clear whether that meant mogas was
legal even without an STC.

-Dana

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Dana M. Hague d(dash)m(dash)hague(at)comcast(dot)net wrote in
:

Back in the 1980's when I still had my 1941 T-Craft (which had an A-65
and ran fine on the leaded regular mogas which was still available at
a few stations then), I looked at the type certificate and all it said
was "73 octane minimum". Never was clear whether that meant mogas was
legal even without an STC.


Well, kinda. Avgas was only relatively new when tha airplane was made. Most
antiquers today shy away from avgas if at all possible (I'm talking about
guys running early Wrights and Kinners and so on now) My LeBlond specifies
a minimum of 60 octane, which is basically carrot juice and doesn't like
lead at all..There was an Avgas, before my time, that was a levle below 80.
90 was still available, though scare, when I started and I have seen
115/145 not all that long ago in places that DC7s and what not were still
frequenting and any place the US Navy was still operating P-2 s in earnest
like Keflavik.
IIRC the 115/145 was purple, the 90/98 was blue and the 70ish octane stuff
was brownish yellow, but never having seen it I only knew that from
whatever books or lists still carried that info.
But the little pre-war designed flat fours were widely run on mogas after
80 started getting scarce, STC or no STC. The FAA doesn't seem to be too
bothered about it.



Bertie

Go to:

http://books.google.com/books?id=QhE...eKUVPA#PPP1,M1

Checked this URL and works for me from this posting.

Good info on aircraft fuels from 30's on.

Big John

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


On Thu, 8 Nov 2007 03:51:48 +0000 (UTC), Bertie the Bunyip
wrote:

Dana M. Hague d(dash)m(dash)hague(at)comcast(dot)net wrote in
:

Back in the 1980's when I still had my 1941 T-Craft (which had an A-65
and ran fine on the leaded regular mogas which was still available at
a few stations then), I looked at the type certificate and all it said
was "73 octane minimum". Never was clear whether that meant mogas was
legal even without an STC.


Well, kinda. Avgas was only relatively new when tha airplane was made. Most
antiquers today shy away from avgas if at all possible (I'm talking about
guys running early Wrights and Kinners and so on now) My LeBlond specifies
a minimum of 60 octane, which is basically carrot juice and doesn't like
lead at all..There was an Avgas, before my time, that was a levle below 80.
90 was still available, though scare, when I started and I have seen
115/145 not all that long ago in places that DC7s and what not were still
frequenting and any place the US Navy was still operating P-2 s in earnest
like Keflavik.
IIRC the 115/145 was purple, the 90/98 was blue and the 70ish octane stuff
was brownish yellow, but never having seen it I only knew that from
whatever books or lists still carried that info.
But the little pre-war designed flat fours were widely run on mogas after
80 started getting scarce, STC or no STC. The FAA doesn't seem to be too
bothered about it.



Bertie