MoGas Long Term Test: 5000 gallons and counting...

BTIZ wrote:

Actually I think it was available up into the mid to late 70s...

80/88, and it was colored Red...


Red gas was available in some places until fairly recently
(historically speaking). My airport was selling it right up until
2002.

Oddly enough, I saw some red gas the other day. My tiedown
neighbor owns a 150 that never flies. Every few years, he spends
several thousand on an annual and maintenance, then ends up not flying.
The cycle repeats every other year.

Just the other day he had a team of A&Ps and IA surrounding the plane
on the ramp, getting it ready to fly again. He's finally selling it.
When he sampled the fuel and it came out red colored, everyone on the
ramp just busted out laughing. We figured he had the last surviving
example of 80/87 aviation gas in the country. Too bad such rarity
doesn't make his ramp queen worth any more :-(

John Galban=====N4BQ (PA28-180)


John Galban=====N4BQ (PA28-180)

I got my last tankful of 80/87 at RBL about November of last year,
awhile after the last refiner stopped producing it. It had become a
rarity over the last ten years or so - you had to know where to go to
get it.

David Johnson

: Detonation is NEVER a problem when the octane is correct. If the engine
: is designed for 80 octane, it will happily drink 80 octane mogas or
: anything else that meets the minimum spec. The absence of lead in the
: fuel simply means that there is less junk to scavenge out of the
: combustion products.

That's not completely true. Some engines are marginal on their rated fuel (in
particular, fire-breathing TGSIO-ABC-XYZ-540's putting out 350 hp or whatever). Even
some planes could be marginal on their rated fuel in the worse possible condition.
For example, long climb, just under redline CHT, fuel at the bottom of the permissible
octane rating, carb float/jets at the leanest possible configuration, etc, etc.

The bigger variable is that autofuel does not use quite the same rating as
avgas. Autofuel (in the U.S. anyway) uses an (R+M)/2 rating, or anti-knock-index
(A.K.I). The point spread between the two is not published, but is generally about
\pm 5 points, with the lower (motor) most closely similar to the aviation method.
Basically, that means that 87 AKI autogas is probably about 82 motor, 92 research.

-Cory

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Jim Carriere wrote:

Awww, anecdotal evidence. Statistically speaking, you need a larger
sample size

Actually would be more like a longitudinal case study... same subject
evaluated over a long period of time. Applicable only to the individual,
or perhaps a population of similar subjects... but still a valid data point.

I like the bit about the hours/years on the spark plug...

Dave

"Jay Honeck" wrote in message
news:y6zfe.67777$WI3.10767@attbi_s71...
Yesterday I noticed that we had pumped more than 5000 gallons of mogas
through the Mighty Grape. This represents something like 60 complete
fills
(our plane has four gas tanks, totaling 84 gallons), and around 350 hours
of
flight time over the last 2.5 years.

(See: http://alexisparkinn.com/fuel_truck.htm for details on our Jim
Weir-inspired fuel truck, the "Mighty Grape"...)

At an average saving of over $1 per gallon (at the moment, it's more like
$1.25), we have paid for the truck (which we use extensively at the
hotel),
the tank & pump installation (which has worked flawlessly from "Day
One") --
and put aside over $2500 toward our next overhaul.

Best of all, Atlas (our Lycoming O-540-powered Cherokee Pathfinder) simply
runs best on regular, 87-octane unleaded car gasoline. In fact, the ONLY
time we've had trouble with our new engine has been when we were forced to
buy 100LL avgas, which causes lead-fouling of our spark plugs at the drop
of
a hat.

All the worries that people stated, both personally and here in this
forum,
have turned out to be entirely baseless. After flying with mogas for the
last 2.5 years, I can unequivocally state the following:

1. Mogas works better in my plane than avgas. Our engine runs noticeably
better on mogas.
2. I have had no problems with contamination of any kind (my pump/tank
installation has a very good filtration system)
3. If we've run across any ethanol, the engine has never burped because of
it.
4. We've run mogas from sea level to 13,500 feet, in temperatures from -15
to +97 degrees Fahrenheit, without problem.

Because of this, I state further that:

1. I would burn mogas in my plane even if it cost MORE than avgas -- it
runs
that much better.
2. I will never buy a plane that doesn't have the auto gas STC.

The autogas STC is undoubtedly the best thing that has ever happened to
aircraft owners. If you've got the STC, but aren't using it, you are
literally flushing thousands of dollars down the toilet.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"


The only down side to mogas I have noticed is the smell.

Dave Stadt wrote:


The only down side to mogas I have noticed is the smell.



I had a friend who liked to sniff gasoline, once.

God rest his soul.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

On 2005-05-09, Jay Honeck wrote:
Best of all, Atlas (our Lycoming O-540-powered Cherokee Pathfinder) simply
runs best on regular, 87-octane unleaded car gasoline.

Unfortunately the engine isn't the only consideration. For some reason
the Comanche is subject to vapor lock with mogas so there is no STC
available.

What's really sad is that last year this time I was paying less for avgas
than I am *now* for mogas.

--
Ben Jackson

http://www.ben.com/

Jay,

Have you run 93 octane?


Trip

In article y6zfe.67777$WI3.10767@attbi_s71, says...

Yesterday I noticed that we had pumped more than 5000 gallons of mogas
through the Mighty Grape. This represents something like 60 complete fills
(our plane has four gas tanks, totaling 84 gallons), and around 350 hours of
flight time over the last 2.5 years.

(See: http://alexisparkinn.com/fuel_truck.htm for details on our Jim
Weir-inspired fuel truck, the "Mighty Grape"...)

At an average saving of over $1 per gallon (at the moment, it's more like
$1.25), we have paid for the truck (which we use extensively at the hotel),
the tank & pump installation (which has worked flawlessly from "Day One") --
and put aside over $2500 toward our next overhaul.

Best of all, Atlas (our Lycoming O-540-powered Cherokee Pathfinder) simply
runs best on regular, 87-octane unleaded car gasoline. In fact, the ONLY
time we've had trouble with our new engine has been when we were forced to
buy 100LL avgas, which causes lead-fouling of our spark plugs at the drop of
a hat.

All the worries that people stated, both personally and here in this forum,
have turned out to be entirely baseless. After flying with mogas for the
last 2.5 years, I can unequivocally state the following:

1. Mogas works better in my plane than avgas. Our engine runs noticeably
better on mogas.
2. I have had no problems with contamination of any kind (my pump/tank
installation has a very good filtration system)
3. If we've run across any ethanol, the engine has never burped because of
it.
4. We've run mogas from sea level to 13,500 feet, in temperatures from -15
to +97 degrees Fahrenheit, without problem.

Because of this, I state further that:

1. I would burn mogas in my plane even if it cost MORE than avgas -- it runs
that much better.
2. I will never buy a plane that doesn't have the auto gas STC.

The autogas STC is undoubtedly the best thing that has ever happened to
aircraft owners. If you've got the STC, but aren't using it, you are
literally flushing thousands of dollars down the toilet.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

: The autogas STC is undoubtedly the best thing that has ever happened to
: aircraft owners. If you've got the STC, but aren't using it, you are
: literally flushing thousands of dollars down the toilet.
: --

I agree on that. I will add one more datapoint to the mix here. We put the
Petersen high-compression autogas STC on our Cherokee-180 (requires 91 A.K.I or
better) about two years ago. Due to the difference in fuel ratings, I was concerned
about detonation margin. We've got 93 A.K.I pump-gas here, which is what I use.
Basically, that means the motor octane is probably about 88... less than the 91 the
O-360-A3A was type-certificated at.

I generally run at least 20% 100LL on the takeoff (right) tank, and 100% autogas on
the left for local cruises. I've done enough local flying with long climbs, hot
takeoffs, different mixtures, etc and haven't noticed any ill effects. I'm sure that
you cannot forget to enrichen at *all* when operating on mogas, but I haven't had any
issues. For the record, Petersen said when they did the vapor lock/detonation testing
(in some ridiculously hot desert place at 100+ degrees IIRC), they couldn't get it to
detonate on 89 mid-grade either. The FAA guys insisted on a little "safety-margin"
and made it 91.

On thing I did (rather accidentally) find out about that initially disturbed
me. I shut down the engine with the mags after a flight (I just had to jump out and
get something from my car and didn't want to have to prime it to start). It *almost*
died, but started to diesel at a ridiculously low RPM (100 or so). Dieseling =
preignition = BAD... BUT, the big problems are these:

- Extremely low RPM makes for a *LONG TIME* (20x that of takeoff time) that the
mixture is in the hot cylinders. It's got extra time to decide to light off.
- Extremely low RPM makes even the idle throttle setting "full-throttle." The MP
gauge said basically atmospheric (26-28"), even at idle setting of the throttle. Each
cylinder gets a full-throttle gulp of mixture then which can slow-bake in the jugs.
- Idle mixture is generally set for slightly rich (not super-rich)... best mixture for
preignition.

Concerned, I tried it in a friend's PA-28-150 running 87 autogas. Same thing,
and that engine combo config is identical to Jay's... just 4 rather than 6. Nobody
ever has had issues with octane on the low-compression engines.

Anyway, I'd be interested to hear if you can do the same trick, Jay. I'm
pretty convinced (due to the above reasons) that it's a non-issue for normal
operation. Interesting, though.

-Cory


--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

writes:

: The autogas STC is undoubtedly the best thing that has ever happened to
: aircraft owners. If you've got the STC, but aren't using it, you are
: literally flushing thousands of dollars down the toilet.

I'd love to get the STC for my Skylane, but I'm told that all gas sold
in California these days has alcohol in it, so I'm S.O.L.

-jav