Question about auto gas STC

"zatatime" wrote in message
...
While that's true you couldn't make a much worse choice than a Grumman.



My point was to open the poster up to the idea that a different
airplane may better suit his needs. While I'm not a big fan of most
Grummans I know people who love them so I offered it as one of two
alternatives. Maybe I should have said something like...Insert
alternative manufacturer here...instead of being specific.

A Grumman has its place. But it ain't trying to get off the ground at an
8000' DA.

In article ,
(Robert M. Gary) wrote:

(JimT96309) wrote in message
...
I am currently interested in an older C-172 (Cont. 0-300 engine) that has
an
STC for auto gas. My questions a

1. Can I continue to use AVgas instead of auto fuel?

2. I often fly into/out of Big Bear City, Ca. (elev. 6500ft.) I've been
able
to get out lightly loaded (me and one in the right seat) at a density
altitude
of 8,100 with one of our clubs 172s with the 320H2AD engines at 160 hp.
What
difference would I see with the 15 fewer horses up front?

I'm not 100% sure about the Big Bear area, but in most parts of
California the FAA prohibits the use of autogas. Autogas in Ca usually
(depending on the county) contains MTBE which is prohibited by the FAA
because it eats fuel lines.

-Robert

WRONG! MTBE is an approved additive, while alcohol is NOT.

"Robert M. Gary" wrote:

I'm not 100% sure about the Big Bear area, but in most parts of
California the FAA prohibits the use of autogas. Autogas in Ca usually
(depending on the county) contains MTBE which is prohibited by the FAA
because it eats fuel lines.

--------------- begin quote -------------------

On December 14, 1992, EAA received clarification from the FAA that: "Automobile
gasoline blended with MTBE is approved for use in aircraft that are approved for use
of automobile gasoline STC's." EAA, Petersen Aviation and others have worked with the
FAA to have MTBE "approved" based on the common industry knowledge that it has been
in automobile gasoline for years. The FAA's determination that gasoline blended with
MTBE can be used safely in aircraft (that are STC approved) was based, in part, on
FAA tests, research and review of service difficulty reports. No material
compatibility or performance problems were found. The FAA also approved the use of
automobile gasoline that contains ETBE on December 1, 1995. This approval was based
on flight test, ground tests and material compatibility test performed by EAA, FAA
and Petersen Aviation.

George Patterson
None of us is as dumb as all of us.

1. Can I continue to use AVgas instead of auto fuel?

Yes, but:

a) Your engine will run cleaner, better and longer on unleaded car gas

and

b) By burning auto fuel you will save enough over the life of the engine to
buy another new engine.

The Mogas STC is the best value in flying. You'd be crazy not to use it if
you've got it.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:
: 1. Can I continue to use AVgas instead of auto fuel?

: Yes, but:

: a) Your engine will run cleaner, better and longer on unleaded car gas

: and

: b) By burning auto fuel you will save enough over the life of the engine to
: buy another new engine.

: The Mogas STC is the best value in flying. You'd be crazy not to use it if
: you've got it.

*Particularly* on a low-compression engine. The Cont O-200/O-300's in the
older Cessnas are much happier on cargas. Same thing for the low-compression Lyc.
O-320's and O-540s. The high-compression engines (like my 180 hp O-360) are a little
bit more marginal... not from an engine life, but from a detonation margin. The
Peterson STC specifies 91 AKI (R+M/2), but the aviation lean rating (91 of the 91/96
of this engine's type certificated fuel) is closer to the Motor octane rating of the
AKI. Since 91 AKI cargas might have a Motor rating of 86 or so, it's a bit marginal.
I run 93 AKI and keep at least 15% 100LL in the takeoff tank for the octane boost of
the TEL. The effects of TEL are quite nonlinear (i.e. a little gives you a lot, but a
lot doesn't give much more). That said, I've got about 200 hours of cargas on my
plane and it's so far happier (as am I having saved over $1500 so far).

-Cory



--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

"G.R. Patterson III" wrote in message ...
"Robert M. Gary" wrote:

I'm not 100% sure about the Big Bear area, but in most parts of
California the FAA prohibits the use of autogas. Autogas in Ca usually
(depending on the county) contains MTBE which is prohibited by the FAA
because it eats fuel lines.

--------------- begin quote -------------------

On December 14, 1992, EAA received clarification from the FAA that: "Automobile
gasoline blended with MTBE is approved for use in aircraft that are approved for use
of automobile gasoline STC's." EAA, Petersen Aviation and others have worked with the
FAA to have MTBE "approved" based on the common industry knowledge that it has been
in automobile gasoline for years. The FAA's determination that gasoline blended with
MTBE can be used safely in aircraft (that are STC approved) was based, in part, on
FAA tests, research and review of service difficulty reports. No material
compatibility or performance problems were found. The FAA also approved the use of
automobile gasoline that contains ETBE on December 1, 1995. This approval was based
on flight test, ground tests and material compatibility test performed by EAA, FAA
and Petersen Aviation.

That's interesting. I called the EAA a year ago when I was looking at
buying another Aeronca and was told otherwise. I guess you can't
necessarily trust the guy on the phone.

"Jay Honeck" wrote in message news:ivFvc.36969$3x.36311@attbi_s54...
1. Can I continue to use AVgas instead of auto fuel?

Yes, but:

a) Your engine will run cleaner, better and longer on unleaded car gas

and

b) By burning auto fuel you will save enough over the life of the engine to
buy another new engine.

The Mogas STC is the best value in flying. You'd be crazy not to use it if
you've got it.

We had create luck with autogas in the Chief. Kept the engine clean.
The lower octane really makes things run nicer too. 100LL would crud
up the works pretty fast. This is especially bad for those planes that
don't have a mixture control.

We had create luck with autogas in the Chief. Kept the engine clean.
The lower octane really makes things run nicer too. 100LL would crud
up the works pretty fast. This is especially bad for those planes that
don't have a mixture control.

I paid $3.30 a gallon for Avgas in Ankeny today!

I paid $1.92 for mogas in Iowa City yesterday.

The math is self-evident -- mogas is the way to go!

BTW: What planes don't have mixture controls? (Beside turbines and jets?)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:
: I paid $3.30 a gallon for Avgas in Ankeny today!

: I paid $1.92 for mogas in Iowa City yesterday.

: The math is self-evident -- mogas is the way to go!

I paid $2.29 for 93 octane premium unleaded in Mansfield the other day.
I paid $2.60 for 100LL in Columbia County, NY (1B1) the other day.
For me, the math is self evident, but the other way! (Break even with STC
costs @ 10000 gallons or 1000 hours!)

: BTW: What planes don't have mixture controls? (Beside turbines and jets?)
A lot of older, pre WW2 airplanes with small engines, less than 85 HP.
--
Aaron Coolidge (N9376J)

Aaron Coolidge wrote:

I paid $2.29 for 93 octane premium unleaded in Mansfield the other day.
I paid $2.60 for 100LL in Columbia County, NY (1B1) the other day.
For me, the math is self evident, but the other way! (Break even with STC
costs @ 10000 gallons or 1000 hours!)

Something is wrong with your math.

@ $0.31 price difference per gallon, it would only take 741 gallons to
pay for the $230 STC (O470, 230HP, $1 per HP).

My price difference between 100LL and 86 Octane autogas has typically been
$0.75 to $1 per gallon. I figure that between overhauls of my engine (~2000
hours, buring 12 gph), I saved a minimum of 12 * 2000 * 0.75 = $18,000,
which is what the last overhaul cost...

MikeM