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

[Jay Honeck]

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"

[Jim Carriere]

Jay Honeck wrote:
> 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.

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

But seriously, a good post, well documented.

'Couple questions-

Do you use the same spark plugs (and same heat range) as before going
to mogas?

Do you lean, and how lean? What kind of numbers do you usually see
in different regimes of flight (EGT, CHT)? Obviously detonation
hasn't been a problem for you, I'm curious how hot you can get away
with on that engine with regular auto fuel.

Thanks.

OK, 3 questions, if you save a buck a gallon on 5000 gallons, and but
$2500 to the next overhaul, the other $2500 must buy a lot of good
beer, right?

[Jay Honeck]

> Do you use the same spark plugs (and same heat range) as before going to
> mogas?

Yep. Although because they foul too easily with 100LL (which we must buy on
long-cross-country flights), I'm probably going to go with a hotter plug
when these die.

> Do you lean, and how lean? What kind of numbers do you usually see in
> different regimes of flight (EGT, CHT)? Obviously detonation hasn't been
> a problem for you, I'm curious how hot you can get away with on that
> engine with regular auto fuel.

Sure do. At take off power, full rich, we're burning 25 gph. At cruise we
tend to run 23 squared, leaned back to 15 gph. At this setting we'll see
EGTs in the 1350 - 1450 degree range, and CHTs in the 300 - 325 degree
range.

We can, of course, throttle back to 20 squared, and burn 10 gph or less.
Danged engine is so quiet at that power setting, it's almost spooky.

> OK, 3 questions, if you save a buck a gallon on 5000 gallons, and but
> $2500 to the next overhaul, the other $2500 must buy a lot of good beer,
> right?

Nah, beer is extra! :-)

The Grape itself cost $1800, and the tank/pump installation (and a couple of
other things) make up the other $700 or so.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Dave Stadt]

"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.

[ORVAL FAIRBAIRN]

In article >,
Jim Carriere > wrote:

> Jay Honeck wrote:
> > 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.
>
> Awww, anecdotal evidence. Statistically speaking, you need a larger
> sample size :)
>
> But seriously, a good post, well documented.
>
> 'Couple questions-
>
> Do you use the same spark plugs (and same heat range) as before going
> to mogas?


I do, too -- plugs last longer without the lead in the fuel.



> Do you lean, and how lean? What kind of numbers do you usually see
> in different regimes of flight (EGT, CHT)? Obviously detonation
> hasn't been a problem for you, I'm curious how hot you can get away
> with on that engine with regular auto fuel.


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.

BTW, how many out there are aware that 80 octane unleaded avgas used to
be available, back in the 40s and 50s?

--
Remove _'s from email address to talk to me.

[BTIZ]

> BTW, how many out there are aware that 80 octane unleaded avgas used to
> be available, back in the 40s and 50s?
>
> --


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

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

BT

[Ben Jackson]

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/

[Scott Skylane]

Jay Honeck wrote:
/snip/
> Sure do. At take off power, full rich, we're burning 25 gph. At cruise we
> tend to run 23 squared, leaned back to 15 gph. At this setting we'll see
> EGTs in the 1350 - 1450 degree range, and CHTs in the 300 - 325 degree
> range.
/snip/

Jay,

Huh??? On my 230 hp O-470, I cruise at 23-squared, without any fancy
engine monitors. Using the "pull-until-it-feels-about-right" method of
leaning, I get 12 gph. Religeously. You can set your watch by that
figure. I wonder if using mogas is somehow requiring you to run 25%
richer than avgas? If so, what are your corrected savings per hour?

On a side note, as I asked you earlier, what part # spark plugs are you
running? I am curious due to your undue propensity to fouling while
running avgas.

Happy Flying!
Scott Skylane
N92054

[kontiki]

Jay Honeck wrote:
> Sure do. At take off power, full rich, we're burning 25 gph. At cruise we
> tend to run 23 squared, leaned back to 15 gph. At this setting we'll see
> EGTs in the 1350 - 1450 degree range, and CHTs in the 300 - 325 degree
> range.
My Comanche has an O-540 and at 22/23 I'm burning about 13 Gph with 100LL.
If there was an MOGAS STC for the Comanche I'd give it a try but that will
never happen.

[Denny]

Fat Albert the Apache dines on a diet of the cheapest, stinkiest,
crapola, 83 octane, gas I can find... He only gets toxic, lead spewing,
plug fouling, valve sticking, 100LL, on trips where I can't get to the
gas station....

My mechanic is mumbling because the plugs have gone 4 years and way
over 400 hours and are going strong... This annual he said he HAD to
change the plugs because of the hours, he felt he JUST couldn't sign
them off for another year... I said, "Fine, JUST as long as you are
paying for them!"... He changed the subject...


I lean by the EGT at 70% or higher... On local flights I am normally at
60 - 65% power, lean em until they go rough, and smile...

ymmv, sar, bni

denny

[Jay Honeck]

> Huh??? On my 230 hp O-470, I cruise at 23-squared, without any fancy
> engine monitors. Using the "pull-until-it-feels-about-right" method of
> leaning, I get 12 gph.

I can lean to that fuel flow without any undue engine sounds, too. But my
EGTs go well over 1500 degrees, and my CHTs push 350 when I do.

I would rather burn a bit more gas.

> On a side note, as I asked you earlier, what part # spark plugs are you
> running? I am curious due to your undue propensity to fouling while
> running avgas.

I have no idea, and I don't have my logs handy. However, as I said, I will
be replacing them with a hotter-burning plug when they wear out.

Of course, without all that lead fouling, they may never wear out!

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Dave S]

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

[Matt Barrow]

"Jay Honeck" > wrote in message
news:shJfe.64410$r53.14308@attbi_s21...
> > On a side note, as I asked you earlier, what part # spark plugs are you
> > running? I am curious due to your undue propensity to fouling while
> > running avgas.
>
> I have no idea, and I don't have my logs handy. However, as I said, I
will
> be replacing them with a hotter-burning plug when they wear out.
>
> Of course, without all that lead fouling, they may never wear out!

And I've never had a fouled plug (at all...nada) in the 1400 hours I've had
my airplane, burning nothing but 100LL (TN IO-550). Maybe you're just
unlucky :~)

[Frank Ch. Eigler]

"Jay Honeck" > writes:

> > Huh??? On my 230 hp O-470, I cruise at 23-squared, without any fancy
> > engine monitors. Using the "pull-until-it-feels-about-right" method of
> > leaning, I get 12 gph.
>
> I can lean to that fuel flow without any undue engine sounds, too. But my
> EGTs go well over 1500 degrees, and my CHTs push 350 when I do.
> I would rather burn a bit more gas. [...]

OK, but that brings into doubt your assertion about your fueling style
being a big cost savings, doesn't it? Using 25% more fuel at 70% of
the cost per unit volume is only about a 10% savings. Or maybe you
didn't lean aggressively on avgas either?

- FChE

[Jay Honeck]

> > I can lean to that fuel flow without any undue engine sounds, too.
But my
> > EGTs go well over 1500 degrees, and my CHTs push 350 when I do.
> > I would rather burn a bit more gas. [...]
>
> OK, but that brings into doubt your assertion about your fueling
style
> being a big cost savings, doesn't it? Using 25% more fuel at 70% of
> the cost per unit volume is only about a 10% savings. Or maybe you
> didn't lean aggressively on avgas either?

Right -- I leaned no differently with avgas. A cooler running engine
will, all other things being equal, last longer.

I *can* lean a lot more, push my EGTs over 1500 degrees, push my CHTs
to 350+ degrees, save some gas -- and risk my new engine.

Now, of course, there are many theories on leaning (I've read 'em all),
but with my normally aspirated engine having such (relatively)
unbalanced fuel flow to each cylinder, I don't feel comfortable
aggressively leaning.

If I had fuel injected, balanced-flow GAMI-jectors, I'd be singing a
different tune.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Newps]

Jay Honeck wrote:

>
>
> At cruise we
> tend to run 23 squared, leaned back to 15 gph.

????? No wonder you got fouled plugs. You should be around 13 gph at
23 squared for a 230 hp engine.

[Newps]

Jay Honeck wrote:

>>Huh??? On my 230 hp O-470, I cruise at 23-squared, without any fancy
>>engine monitors. Using the "pull-until-it-feels-about-right" method of
>>leaning, I get 12 gph.
>
>
> I can lean to that fuel flow without any undue engine sounds, too. But my
> EGTs go well over 1500 degrees, and my CHTs push 350 when I do.

EGT is irrelavant and 350 is not hot.

[Corky Scott]

On 9 May 2005 10:21:51 -0700, "Jay Honeck" > wrote:

>I *can* lean a lot more, push my EGTs over 1500 degrees, push my CHTs
>to 350+ degrees, save some gas -- and risk my new engine.
>
>Now, of course, there are many theories on leaning (I've read 'em all),
>but with my normally aspirated engine having such (relatively)
>unbalanced fuel flow to each cylinder, I don't feel comfortable
>aggressively leaning.

John Deakin has written that if you lean to the lean side of peak and
the engine runs rough, pulling on full carb heat will distribute the
fuel into the air mixture better and give you the ability to lean to
the lean side of peak.

You might just try it, if only for a little bit if you are too
uncomfortable with the process.

Corky Scott

[TripFarmer]

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"
>
>

[[email protected]]

Corky Scott wrote:
>
> John Deakin has written that if you lean to the lean side of peak and
> the engine runs rough, pulling on full carb heat will distribute the
> fuel into the air mixture better and give you the ability to lean to
> the lean side of peak.
>
> You might just try it, if only for a little bit if you are too
> uncomfortable with the process.
>

Doesn't always work. I tried it on the O-360 in my Cherokee and the
carb heat made no difference. It still stumbled right after peaking.
Induction systems are different from plane to plane and even from year
to year on the same model. The carb heat trick does work on certain
planes that I fly, so I think it's worth a try. Just don't get your
hopes up.

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

[[email protected]]

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)

[Ernest Christley]

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)."

[Blueskies]

"Jay Honeck" > wrote in message news:_eAfe.67985$WI3.223@attbi_s71...
>
> The Grape itself cost $1800, and the tank/pump installation (and a couple of other things) make up the other $700 or
> so.
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"
>

Any more details about The Grape?

[[email protected]]

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

[Matt Barrow]

"Corky Scott" > wrote in message
...
> On 9 May 2005 10:21:51 -0700, "Jay Honeck" > wrote:
>
> >I *can* lean a lot more, push my EGTs over 1500 degrees, push my CHTs
> >to 350+ degrees, save some gas -- and risk my new engine.
> >
> >Now, of course, there are many theories on leaning (I've read 'em all),
> >but with my normally aspirated engine having such (relatively)
> >unbalanced fuel flow to each cylinder, I don't feel comfortable
> >aggressively leaning.
>
> John Deakin has written that if you lean to the lean side of peak and
> the engine runs rough, pulling on full carb heat will distribute the
> fuel into the air mixture better and give you the ability to lean to
> the lean side of peak.

Actually, he says "just a touch" of carb heat.

>
> You might just try it, if only for a little bit if you are too
> uncomfortable with the process.

[Matt Barrow]

> wrote in message
oups.com...
>
> Corky Scott wrote:
> >
> > John Deakin has written that if you lean to the lean side of peak and
> > the engine runs rough, pulling on full carb heat will distribute the
> > fuel into the air mixture better and give you the ability to lean to
> > the lean side of peak.
> >
> > You might just try it, if only for a little bit if you are too
> > uncomfortable with the process.
> >
>
> Doesn't always work. I tried it on the O-360 in my Cherokee and the
> carb heat made no difference. It still stumbled right after peaking.
> Induction systems are different from plane to plane and even from year
> to year on the same model. The carb heat trick does work on certain
> planes that I fly, so I think it's worth a try. Just don't get your
> hopes up.
>
Deakin was talking about the engine in the Skylane with the whatsitsname
carburator.

http://www.avweb.com/news/columns/182084-1.html

"Here's another tip for carbureted engines, if you're operating high enough
to use full throttle, or nearly so. From the full-throttle position, pull
the throttle back until you observe the slightest drop in MP - perhaps a
quarter-inch or less. Leave it there. That will cock the throttle plate a
little, just enough to set up a vortex that will cause better atomization
and mixing of the fuel and air. (This is counterproductive in fuel injected
engines.)"

In a previous post, I'd said he recommended adding a "touch of carb heat" --
sorry.

[Jay Honeck]

>> The Grape itself cost $1800, and the tank/pump installation (and a couple
>> of other things) make up the other $700 or so.
>
> Any more details about The Grape?

See: http://alexisparkinn.com/fuel_truck.htm

If you have any other questions, please feel free to ask.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Montblack]

("Blueskies" wrote)
> Any more details about The Grape?


Jay might finally be willing to allow a "Purple Pride" bumper sticker on The
Mighty Grape ...now that Randy Moss has been sent to Oakland. <g>

Probably not though.


Montblack
45 years of Purple

[Corky Scott]

On Mon, 9 May 2005 18:44:11 -0700, "Matt Barrow"
> wrote:

>> John Deakin has written that if you lean to the lean side of peak and
>> the engine runs rough, pulling on full carb heat will distribute the
>> fuel into the air mixture better and give you the ability to lean to
>> the lean side of peak.
>
>Actually, he says "just a touch" of carb heat.

That was his initial suggestion. In his next column he posted this as
a news flash. I've posted nearly the entire portion of the column
because he has some caveats that are important to understand:

***Begin Quote***
We've always suggested trying just a touch of carb heat to improve
mixture distribution, but that was always an afterthought, secondary
to the tiny MP reduction with throttle, and we had no data.

Walter has been playing with AMPLE carburetor heat, even full
carburetor heat! On his airplane, and on a couple flat engines he's
tried, it works like a charm! It brings the EGTs and CHT into close
alignment (which isn't all that important), but more important, it
evens up the mixtures to each combustion chamber, allowing smooth and
LOP operations for the first time in some of these engines!

You heard it here first, thanks entirely to Walter. We need more data
on this to be sure it's a universal solution, or if it's peculiar to
certain engines.

There are a couple of very minor "problems" with using carb heat. One
is that on most engines, it bypasses the intake air filter and takes
combustion air from inside the warm engine compartment, or from a muff
around the exhaust tubes. Any sand, dust, or debris in the air can get
sucked into the engine, and that's not really too beneficial. On the
other hand, a lot of engines run without air filters entirely
(Walter's Twin Beech being one), apparently without much harm. Doing
this may cause a small elevation in silicone in your oil analysis, but
it's not clear how harmful this might be. Simple answer to this is
just don't use carb heat on the ground, except for testing. Or when
flying in a dust storm.

Inflight with carb heat on, some ram air effect may be lost, costing
you an inch or so of MP on some installations. But when LOP, air isn't
the determinant of power, fuel is.

Finally, using carb heat at *sea level takeoff power on a hot day* may
raise the induction air temperature so much that it will infringe on
the detonation margin if the engine is already "critical." But
full-power operation is not the real problem here, because we
recommend full power and ROP for all takeoffs. At lesser power
settings, or on cold days, even full carburetor heat is not an issue
for detonation, on most of these flat engines.

If any of you have carbureted engines with the JPI instrumentation,
and can download the data, please experiment with this, and send me
the data file. This might best be done by someone who is already a
"user" of our LOP methods, as there will be less "mystery" during the
testing. Just go up to somewhere above 5,000', and try WOT, LOP, and
play with different carb heat settings, including full heat. This is
really looking good, but we need data!

Walter thinks the warmer air is dramatically improving vaporization
and distribution, but we don't know a lot on this, yet.

You WILL run into great "resistance" at your local airport on this!
Just ask, "Do you have the data for that?" We will have, shortly.
Meanwhile, think of the IO-550B on my airplane, where we hung a turbo
on it, and we're using the same full manifold pressure as always, but
now heated dramatically by the turbo. It doesn't seem to hurt. What's
the difference between hot induction air and hot induction air?
Nothing.

This "News Flash" is the ONLY part of this column aimed at carbureted
engines! The main part of the column is about fuel-injected engines.
Sorry for the confusion, but I wanted to get this information out as
soon as possible.


February 2, 2003
Pelican's Perch #65
Where Should I Run My Engine?
(Part 3 -- Cruise)

***End Quote***

Corky Scott

[Jay Honeck]

> Jay might finally be willing to allow a "Purple Pride" bumper sticker on
> The Mighty Grape ...now that Randy Moss has been sent to Oakland. <g>

With Moss' departure, the Vikings have taken one small step back toward
legitimacy. They've still got a long ways to go, however.

When they start playing outside again, I'll know they've returned from the
Dark Side.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Montblack]

("Jay Honeck" wrote)
> With Moss' departure, the Vikings have taken one small step back toward
> legitimacy. They've still got a long ways to go, however.
>
> When they start playing outside again, I'll know they've returned from the
> Dark Side.


With something like a 2-20 record on grass since 2000, I think we'll stay in
the (1982) HHH Metrodome ...for now. "We like it here."

(NAC - Necessary Aviation Content)
Vikings new (proposed) stadium will be north/east of ANE - Anoka
County-Blaine Airport ...about 1 mile.


Montblack

[Dylan Smith]

In article >, Newps wrote:
> Jay Honeck wrote:
>> At cruise we
>> tend to run 23 squared, leaned back to 15 gph.
>
> ????? No wonder you got fouled plugs. You should be around 13 gph at
> 23 squared for a 230 hp engine.

I'd strongly agree with this. I used to fly an S-35 Bonanza with an
IO-520, and I'd get about 13 gph in cruise (at 160 ktas at 8000'). I'd
expect Jay's plane not to burn more than this.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

[Newps]

Matt Barrow wrote:
> "Corky Scott" > wrote in message
> ...
>
>>On 9 May 2005 10:21:51 -0700, "Jay Honeck" > wrote:
>>
>>
>>>I *can* lean a lot more, push my EGTs over 1500 degrees, push my CHTs
>>>to 350+ degrees, save some gas -- and risk my new engine.
>>>
>>>Now, of course, there are many theories on leaning (I've read 'em all),
>>>but with my normally aspirated engine having such (relatively)
>>>unbalanced fuel flow to each cylinder, I don't feel comfortable
>>>aggressively leaning.
>>
>>John Deakin has written that if you lean to the lean side of peak and
>>the engine runs rough, pulling on full carb heat will distribute the
>>fuel into the air mixture better and give you the ability to lean to
>>the lean side of peak.
>
>
> Actually, he says "just a touch" of carb heat.

Set your carb heat to whatever setting gives you a carb temp of 40
degrees. You will notice that your CHT's get really close together then.

[Newps]

Dylan Smith wrote:

> In article >, Newps wrote:
>
>>Jay Honeck wrote:
>>
>>> At cruise we
>>>tend to run 23 squared, leaned back to 15 gph.
>>
>>????? No wonder you got fouled plugs. You should be around 13 gph at
>>23 squared for a 230 hp engine.
>
>
> I'd strongly agree with this. I used to fly an S-35 Bonanza with an
> IO-520, and I'd get about 13 gph in cruise (at 160 ktas at 8000'). I'd
> expect Jay's plane not to burn more than this.

Which also explains why Jay can immediately tell if he is running mogas
or 100LL apparently. I can never tell. It never makes any difference
whatsoever.

[Bela P. Havasreti]

On Tue, 10 May 2005 07:45:07 -0400, Corky Scott
> wrote:

Might be a "news flash" to some, but folks have been "hot leaning"
airplane engines since before I was born.

Bela P. Havasreti

>On Mon, 9 May 2005 18:44:11 -0700, "Matt Barrow"
> wrote:
>
>>> John Deakin has written that if you lean to the lean side of peak and
>>> the engine runs rough, pulling on full carb heat will distribute the
>>> fuel into the air mixture better and give you the ability to lean to
>>> the lean side of peak.
>>
>>Actually, he says "just a touch" of carb heat.
>
>That was his initial suggestion. In his next column he posted this as
>a news flash. I've posted nearly the entire portion of the column
>because he has some caveats that are important to understand:
>
>***Begin Quote***
>We've always suggested trying just a touch of carb heat to improve
>mixture distribution, but that was always an afterthought, secondary
>to the tiny MP reduction with throttle, and we had no data.
>
>Walter has been playing with AMPLE carburetor heat, even full
>carburetor heat! On his airplane, and on a couple flat engines he's
>tried, it works like a charm! It brings the EGTs and CHT into close
>alignment (which isn't all that important), but more important, it
>evens up the mixtures to each combustion chamber, allowing smooth and
>LOP operations for the first time in some of these engines!
>
>You heard it here first, thanks entirely to Walter. We need more data
>on this to be sure it's a universal solution, or if it's peculiar to
>certain engines.
>
>There are a couple of very minor "problems" with using carb heat. One
>is that on most engines, it bypasses the intake air filter and takes
>combustion air from inside the warm engine compartment, or from a muff
>around the exhaust tubes. Any sand, dust, or debris in the air can get
>sucked into the engine, and that's not really too beneficial. On the
>other hand, a lot of engines run without air filters entirely
>(Walter's Twin Beech being one), apparently without much harm. Doing
>this may cause a small elevation in silicone in your oil analysis, but
>it's not clear how harmful this might be. Simple answer to this is
>just don't use carb heat on the ground, except for testing. Or when
>flying in a dust storm.
>
>Inflight with carb heat on, some ram air effect may be lost, costing
>you an inch or so of MP on some installations. But when LOP, air isn't
>the determinant of power, fuel is.
>
>Finally, using carb heat at *sea level takeoff power on a hot day* may
>raise the induction air temperature so much that it will infringe on
>the detonation margin if the engine is already "critical." But
>full-power operation is not the real problem here, because we
>recommend full power and ROP for all takeoffs. At lesser power
>settings, or on cold days, even full carburetor heat is not an issue
>for detonation, on most of these flat engines.
>
>If any of you have carbureted engines with the JPI instrumentation,
>and can download the data, please experiment with this, and send me
>the data file. This might best be done by someone who is already a
>"user" of our LOP methods, as there will be less "mystery" during the
>testing. Just go up to somewhere above 5,000', and try WOT, LOP, and
>play with different carb heat settings, including full heat. This is
>really looking good, but we need data!
>
>Walter thinks the warmer air is dramatically improving vaporization
>and distribution, but we don't know a lot on this, yet.
>
>You WILL run into great "resistance" at your local airport on this!
>Just ask, "Do you have the data for that?" We will have, shortly.
>Meanwhile, think of the IO-550B on my airplane, where we hung a turbo
>on it, and we're using the same full manifold pressure as always, but
>now heated dramatically by the turbo. It doesn't seem to hurt. What's
>the difference between hot induction air and hot induction air?
>Nothing.
>
>This "News Flash" is the ONLY part of this column aimed at carbureted
>engines! The main part of the column is about fuel-injected engines.
>Sorry for the confusion, but I wanted to get this information out as
>soon as possible.
>
>
>February 2, 2003
>Pelican's Perch #65
>Where Should I Run My Engine?
>(Part 3 -- Cruise)
>
>***End Quote***
>
>Corky Scott

[Matt Barrow]

"Corky Scott" > wrote in message
...
> On Mon, 9 May 2005 18:44:11 -0700, "Matt Barrow"
> > wrote:
>
> >> John Deakin has written that if you lean to the lean side of peak and
> >> the engine runs rough, pulling on full carb heat will distribute the
> >> fuel into the air mixture better and give you the ability to lean to
> >> the lean side of peak.
> >
> >Actually, he says "just a touch" of carb heat.
>
> That was his initial suggestion. In his next column he posted this as
> a news flash. I've posted nearly the entire portion of the column
> because he has some caveats that are important to understand:
>
> ***Begin Quote***
{snip]
> ***End Quote***
>
> Corky Scott

I hope to hell you cut and pasted all that, rather than typing it in by
hand!! :~)

[Montblack]

("karel" wrote)
[snips]
> Unfortunately it is so full of undocumented abbreviations
> that I can't really make much from it.
> MP must stand for manifold pressure I presume,
> and EGT and CHT are wellknown cause there's instruments for them
> but what the heck are ROP, ONLY, AMPLE, WOP, JIP, LOP ?


ROP - Rich of Peak
LOP - Lean of Peak

ONLY - Only
AMPLE - Ample

WOP...?
WOT - Wide Open Throttle

JIP...?
JPI Instrumentations
http://www.jpinstruments.com/


"WOT" and "JPI" were correct in the ....OP (Original Post) <g>


Montblack

[[email protected]]

karel wrote:

> Corky,
>
> This text must surely be most interesting
> and many people might benefit from understanding,
> myself not the least.
> Unfortunately it is so full of undocumented abbreviations
> that I can't really make much from it.
> MP must stand for manifold pressure I presume,
> and EGT and CHT are wellknown cause there's instruments for them
> but what the heck are ROP, ONLY, AMPLE, WOP, JIP, LOP ?
>
> Is there perhaps a glossary web page somewhere for this kind of
terminology?
>
> KA (learning every day)

I'll make a stab at translating.
ROP -- rich of peak
LOP -- lean of peak
WOP -- I think you mistyped for WOT, wide open throttle
JIP -- I think you mistyped for JPI, a brand of engine instrument.
AMPLE -- emphasized ample, meaning enough to do the job, lots.
ONLY -- emphasized only, meaning singular, just this part of the
newsletter.

Tim Ward

[[email protected]]

In rec.aviation.owning kontiki > wrote:
: My Comanche has an O-540 and at 22/23 I'm burning about 13 Gph with 100LL.
: If there was an MOGAS STC for the Comanche I'd give it a try but that will
: never happen.

I talked with Petersen about the PA-24. It hydro-locks the carb and floods
the engine, so no STC for it. Basically the opposite of vapor-locking AIUI... boiling
fuel pressurizes the carb and forces liquid fuel out. That's different from
vapor-locking where boiling in the lines prevents pumping and it goes dry.

-Cory

--

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

[[email protected]]

: 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 *
************************************************** ***********************

[Corky Scott]

On Tue, 10 May 2005 10:01:47 -0700, "Matt Barrow"
> wrote:

>I hope to hell you cut and pasted all that, rather than typing it in by
>hand!! :~)

You'd be right. Copy and paste. :-)

Corky Scott

[[email protected]]

: 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 *
************************************************** ***********************

[[email protected]]

In rec.aviation.owning Newps > wrote:
: > I can lean to that fuel flow without any undue engine sounds, too. But my
: > EGTs go well over 1500 degrees, and my CHTs push 350 when I do.

: EGT is irrelavant and 350 is not hot.

Exactly. The absolute value of EGT does not matter... almost all of the
cooling of the exhaust valves is done through the valve seat (and stem in Lycoming).
Thus, the "cold sink" is the cylinder, and CHT is what's important. Lycoming redlines
CHT at 500, recommends 450 as a max, and general wisedom dictates anything under
375-400 in cruise is fine.

Also remember that EGT and CHT probes are often uncompensated thermocouples.
That means they read the difference between the "hot" thing, and the temperature of
the "cold" (where the J thermocouple wires connect to the copper wires going to the
meter, etc). They're generally set to be accurate at about 70 degrees F. If it's 0
F, the temp will read 70 degrees hotter than it actually is. Wintertime temps read
higher for that reason.

I don't know about the fancy JPI, etc, by my dumb gauges definately do this.

-Cory



--

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

[LCT Paintball]

> I've a feeling I'm not the only one lost on terminology.

Try being a non pilot trying to keep up with you guys! ;)

[Ernest Christley]

karel wrote:
>
> Still in all seriousness: shouldn't there be a little
> glossary somewhere, perhaps in Ron W's FAQ list?
> I've a feeling I'm not the only one lost on terminology.
>
> KA (learning & learning & ....)
>
>

Stick around. It'll get worse.


--
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)."

[Matt Barrow]

"karel" > wrote in message
...
>
> "Corky Scott" > wrote in message
> ...
> > On Mon, 9 May 2005 18:44:11 -0700, "Matt Barrow"
> > > wrote:
> >
> >>> John Deakin has written that if you lean to the lean side of peak and
> >>> the engine runs rough, pulling on full carb heat will distribute the
> >>> fuel into the air mixture better and give you the ability to lean to
> >>> the lean side of peak.
> >>
> >>Actually, he says "just a touch" of carb heat.
> >
> > That was his initial suggestion. In his next column he posted this as
> > a news flash. I've posted nearly the entire portion of the column
> > because he has some caveats that are important to understand:
> >
> > ***Begin Quote***
>
> (quote snipped)
>
> > ***End Quote***
> > Corky Scott
>
> Corky,
>
> This text must surely be most interesting
> and many people might benefit from understanding,
> myself not the least.
> Unfortunately it is so full of undocumented abbreviations
> that I can't really make much from it.
> MP must stand for manifold pressure I presume,
> and EGT and CHT are wellknown cause there's instruments for them
> but what the heck are ROP, ONLY, AMPLE, WOP, JIP, LOP ?

ROP = Rich of Peak
LOP = Lean of Peak

WOP (WOT) + Wide open throttle

ONLY and AMPLE are _emphasis"

"JIP" I don't se in the article


>
> Is there perhaps a glossary web page somewhere for this kind of
terminology?
>
> KA (learning every day)

There's this http://www.gps.tc.faa.gov/glossary.html but much of aviation's
charm is the acronyms we create every day :~)

[Smitty]

In article >,
"karel" > wrote:

> Was mainly the ROP & LOP that worried me,
> perfectly clear now!
>
> Still in all seriousness: shouldn't there be a little
> glossary somewhere,

Hey, there is a glossary somewhere. It's called www.acronymfinder.com.
Go there and type in ROP, for example, and you'll find the aviation
related definition right there at number 19 in the list.

[Matt Barrow]

"karel" > wrote in message
...
>
> Still in all seriousness: shouldn't there be a little
> glossary somewhere, perhaps in Ron W's FAQ list?
> I've a feeling I'm not the only one lost on terminology.
>

I've seen a book of aviation acronyms and it's several hundred pages. It's
just a part of techical terminology.

Hang around and read as much as you can and you'll discover their terms as
well as their meanings and substance.

Don't feel alone... I didn't know what exactly TSO was until I bought my
first airplane. :~)

> KA (learning & learning & ....)

Hang in there!!

[Javier Henderson]

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

[Corky Scott]

On Tue, 10 May 2005 20:43:34 +0000 (UTC),
wrote:

> Exactly. The absolute value of EGT does not matter... almost all of the
>cooling of the exhaust valves is done through the valve seat (and stem in Lycoming).
>Thus, the "cold sink" is the cylinder, and CHT is what's important. Lycoming redlines
>CHT at 500, recommends 450 as a max, and general wisedom dictates anything under
>375-400 in cruise is fine.

Deakin posts a chart from Pratt and Whitney in his "Mixture Magic"
column which verifies this precisely. In the chart is a line
depicting the loss of strength of the aluminum alloy used for cylinder
heads. It starts dipping LONG before 400 degrees is reached and is
plummeting at 450 degrees.

See: http://www.avweb.com/news/columns/182084-1.html

He recommends running at 400 degrees or under for cruise.

Corky Scott

[Dave Stadt]

"Javier Henderson" > wrote in message
...
> 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

You should be able to find airports that carry mogas that meets the STC
requirements.

[[email protected]]

: Deakin posts a chart from Pratt and Whitney in his "Mixture Magic"
: column which verifies this precisely. In the chart is a line
: depicting the loss of strength of the aluminum alloy used for cylinder
: heads. It starts dipping LONG before 400 degrees is reached and is
: plummeting at 450 degrees.

: See: http://www.avweb.com/news/columns/182084-1.html

: He recommends running at 400 degrees or under for cruise.

I knew I'd read it somewhere and suspected it was a Deakin article. :)

-Cory

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

[RST Engineering]

We can find airports that carry mogas that meet the STC requirements with no
problems. Unfortunately, none of them are in California. The closest one
to me is just east of Salt Lake. Die Governator has decreed that all
gasoline shall be contaminated with 5.5% alcohol before it leaves the
refinery. He didn't make any exceptions for old farm vehicles, lawnmowers,
weedwhackers, or aircraft -- all of which to one degree or another get
honked up with alcohol.

The one thing that keeps burning in the back of my head is that they
probably soaked some of these carb seals in pure alcohol for six months and
said, "look, they swell up" and thus forbade gasahol. My sense, and it is
only a gut feeling, is that if you ran your airplane for a couple of days on
gasahol then let it sit for a couple of weeks in 100LL that you wouldn't see
any deterioration at all. However, you are in direct violation of the STC
if you do so.

It might be nice to have EAA and/or Petersen do the same seal test with 1%
gasahol, 2% gasahol and so on over a short, moderate, and long time to see
the exact problems facing us. Whether we like it or not, gasahol is with us
to stay, at least in California.

Jim


"Dave Stadt" > wrote in message
. ..

> You should be able to find airports that carry mogas that meets the STC
> requirements.
>
>

[nrp]

The Governor of MN just signed us up for 20% alcohol over the next few
years. Soon we'll be able to drink the stuff......

There is a range and max power output penalty for use of alcohol since
it has only about half the energy density of pure hydrocarbon fuel.

[Jay Honeck]

> : He recommends running at 400 degrees or under for cruise.
>
> I knew I'd read it somewhere and suspected it was a Deakin article. :)

Actually, Lycoming says this, too. (It's on their website.)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Montblack]

("nrp" wrote)
> The Governor of MN just signed us up for 20% alcohol over the next few
> years. Soon we'll be able to drink the stuff......


Yup. In Minnesota we've been at 10% ethanol blend for many years. 20% is now
heading down the pipe, into our tanks. I've rebuilt a few lawn mower carbs
because of that darn ethanol.

http://www.msra.com/NonOxygenatedFuel/NonOxyList08.16.04.pdf
Non-Oxygenated (Ethanol-Free) fuel availability in MN

Minnesota Street Rod Association's list
http://www.msra.com/

3 gas stations in St. Paul, MN (300,000 pop.)
3 gas stations in Minneapolis, MN (400,000 pop.)
About 50 gas stations throughout the Twin Cities Metro Area (3.5 million
people)

ALL of the other stations are what we call "outstate." (1 million people)

I was down in Iowa last week. There, stations carry both good gas and the
ethanol junk - your choice. In Minnesota, in the Twin Cities anyway, 95% of
all gas stations sell ONLY the 10% (soon to be 20%) ethanol blend.

North Dakota has consumer choice at the pump - like Iowa. In years of
driving to Minot, ND (510 miles one way) we've noticed at least 10%
improvement in gas mileage with good gas (non-oxygenated) vs. our usual Twin
Cities 10% ethanol blend. I think the mileage improvement has been closer to
15%!! ...which is 40-60 miles every 400.


Montblack

[Javier Henderson]

"Dave Stadt" > writes:

> You should be able to find airports that carry mogas that meets the STC
> requirements.

Yes, but none in California. Plus, the gas in CA leaves the refineries
already containing alcohol, so the ideas about using gas meant for farm
equipment, etc., are non starters.

Grumble.

-jav

[Dave Stadt]

"Javier Henderson" > wrote in message
...
> "Dave Stadt" > writes:
>
> > You should be able to find airports that carry mogas that meets the STC
> > requirements.
>
> Yes, but none in California. Plus, the gas in CA leaves the refineries
> already containing alcohol, so the ideas about using gas meant for farm
> equipment, etc., are non starters.
>
> Grumble.
>
> -jav

That sucks.

[Ernest Christley]

nrp wrote:
> The Governor of MN just signed us up for 20% alcohol over the next few
> years. Soon we'll be able to drink the stuff......
>
> There is a range and max power output penalty for use of alcohol since
> it has only about half the energy density of pure hydrocarbon fuel.
>

It's worse than that, nrp.

Alcohol is hygroscopic. It's going to suck all the water out of the air
that it can, basically destroying that tightly controlled combustion
even there in the cylinder. Someone needs to tell the politicians
pushing the farms subsidies that "wet wood don't burn good"

--
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)."

[Matt Barrow]

"Dave Stadt" > wrote in message
...
>
> "Javier Henderson" > wrote in message
> ...
> > "Dave Stadt" > writes:
> >
> > > You should be able to find airports that carry mogas that meets the
STC
> > > requirements.
> >
> > Yes, but none in California. Plus, the gas in CA leaves the refineries
> > already containing alcohol, so the ideas about using gas meant for farm
> > equipment, etc., are non starters.
> >
> > Grumble.
> >
> > -jav
>
> That sucks.

So move!

[Dave Stadt]

"Matt Barrow" > wrote in message
...
>
> "Dave Stadt" > wrote in message
> ...
> >
> > "Javier Henderson" > wrote in message
> > ...
> > > "Dave Stadt" > writes:
> > >
> > > > You should be able to find airports that carry mogas that meets the
> STC
> > > > requirements.
> > >
> > > Yes, but none in California. Plus, the gas in CA leaves the refineries
> > > already containing alcohol, so the ideas about using gas meant for
farm
> > > equipment, etc., are non starters.
> > >
> > > Grumble.
> > >
> > > -jav
> >
> > That sucks.
>
> So move!

Why should I move? I can get alcohol free mogas. I taxi up and they fill
my tanks. Price is only a couple of cents higher than the local filling
stations.

[[email protected]]

In rec.aviation.owning nrp > wrote:
: There is a range and max power output penalty for use of alcohol since
: it has only about half the energy density of pure hydrocarbon fuel.

Actually, it's about 10% less than that of gasoline IIRC. For automotive
uses, the compression ratio of the engine can be increased to get some of that back,
since the alcohol has a higher octane rating.

-Cory
--

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

[[email protected]]

: It might be nice to have EAA and/or Petersen do the same seal test with 1%
: gasahol, 2% gasahol and so on over a short, moderate, and long time to see
: the exact problems facing us. Whether we like it or not, gasahol is with us
: to stay, at least in California.

From what I've read, it's more than just seals in the fuel system. The
alcohol can attack aluminum fuel tanks, IIRC.

-Cory

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

[Darrel Toepfer]

wrote:

> From what I've read, it's more than just seals in the fuel system. The
> alcohol can attack aluminum fuel tanks, IIRC.

Anybody had mogas issues with fiberglass wing tanks?

[Jay Honeck]

>> From what I've read, it's more than just seals in the fuel system. The
>> alcohol can attack aluminum fuel tanks, IIRC.
>
> Anybody had mogas issues with fiberglass wing tanks?

I've got fiberglass tip tanks.

No problems.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[[email protected]]

In rec.aviation.owning wrote:
: Actually, it's about 10% less than that of gasoline IIRC. For automotive
: uses, the compression ratio of the engine can be increased to get some of that back,
: since the alcohol has a higher octane rating.

: -Cory
: --

I looked into it briefly again today and feel the need to correct myself.
Apparently, the specific energy density of pure ethanol is about 60-70% that of
gasoline. Raising the CR to compensate yields the 10% less range I've heard quoted.

-Cory

--

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

[Morgans]

"Dave Stadt" > wrote

> Why should I move? I can get alcohol free mogas. I taxi up and they fill
> my tanks. Price is only a couple of cents higher than the local filling
> stations.

What state, and what airport?
--
Jim in NC

[Darrel Toepfer]

Morgans wrote:
> "Dave Stadt" > wrote

>>Why should I move? I can get alcohol free mogas. I taxi up and they fill
>>my tanks. Price is only a couple of cents higher than the local filling
>>stations.
>
> What state, and what airport?

Louisiana - 4R7

[Matt Barrow]

"Dave Stadt" > wrote in message
m...
>
> > > >
> > > > Yes, but none in California. Plus, the gas in CA leaves the
refineries
> > > > already containing alcohol, so the ideas about using gas meant for
> farm
> > > > equipment, etc., are non starters.
> > > >
> > > > Grumble.
> > > >
> > > > -jav
> > >
> > > That sucks.
> >
> > So move!
>
> Why should I move? I can get alcohol free mogas. I taxi up and they fill
> my tanks. Price is only a couple of cents higher than the local filling
> stations.
>

I take it you're not in Kalifornia.

In which case, a move would be unnecessary.

[Dave Stadt]

"Darrel Toepfer" > wrote in message
...
> Morgans wrote:
> > "Dave Stadt" > wrote
>
> >>Why should I move? I can get alcohol free mogas. I taxi up and they
fill
> >>my tanks. Price is only a couple of cents higher than the local filling
> >>stations.
> >
> > What state, and what airport?
>
> Louisiana - 4R7

Illinois - C77

[Matt Barrow]

"Dave Stadt" > wrote in message
...
>
> "Darrel Toepfer" > wrote in message
> ...
> > Morgans wrote:
> > > "Dave Stadt" > wrote
> >
> > >>Why should I move? I can get alcohol free mogas. I taxi up and they
> fill
> > >>my tanks. Price is only a couple of cents higher than the local
filling
> > >>stations.
> > >
> > > What state, and what airport?
> >
> > Louisiana - 4R7
>
> Illinois - C77

The issue was the crapped up situation in California...though you still
might want to move :~)

[Jay Honeck]

Today on a long cross-country flight I experimented with the "lean-find"
function on my JPI-700 EGT/CHT meter. As always, it told me to stop leaning
when my fuel flow was right around 15 GPH. (This at 5500 feet, and 23
squared.)

Using the wisdom of the group, I kept pulling the mixture back until my
FS-450 was showing around 13 gph fuel flow, watching the EGTs and CHTs like
a hawk.

Obviously everything did run hotter, but EGTs never topped 1550 degrees, and
CHTs never topped 360 degrees. This is a tad hotter than I've been
running, but the engine sounded fine, and all cylinders stabilized within
100 degrees of each other -- which is as good as it gets on my normally
aspirated O-540.

Later, climbing to 8500 feet, we pulled it back to around 12 gph, with the
same results. (We usually would run around 14 gph at that altitude.)

So, perhaps I've been wasting gas for no good reason. Thanks to all who
responded.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[[email protected]]

In rec.aviation.owning Jay Honeck > wrote:
: Obviously everything did run hotter, but EGTs never topped 1550 degrees, and
: CHTs never topped 360 degrees. This is a tad hotter than I've been
: running, but the engine sounded fine, and all cylinders stabilized within
: 100 degrees of each other -- which is as good as it gets on my normally
: aspirated O-540.

You mean 100 EGT, right? 100 CHT would be pretty horrible, and 100 EGT is
actually pretty ragged. Just for grins, try the same power and try the two different
equalization techniques of Deakin:

- Run high enough (8500 is pretty good) so you can run WOT. Back it off about 1/4" of
MP from full throttle. Cocking the throttle plate slightly like this helps mine.
- Try the carb heat... partial to full.

I've only got analog gauges and a switch to go between them (and two less
jugs). I can say that both of those techniques get my EGT's from within 50-75 degrees
of each other to within 10-25 degrees of each other (as near as I can tell on my
tiny gauge).

YMMV... I suspect the big six on a Cherokee probably has worse fuel distro
than the four in mine.

-Cory

: Later, climbing to 8500 feet, we pulled it back to around 12 gph, with the
: same results. (We usually would run around 14 gph at that altitude.)

What percent power? Just as a datapoint, I'll get about 8.5 gph at 65-70% of
180hp. Adjusted for 6 jugs would be 12.75 gph. The compression ratio doesn't matter
for fuel flow vs. percent.

: So, perhaps I've been wasting gas for no good reason. Thanks to all who
: responded.
: --
Your plugs will be even happier. No lead *or* carbon buildup.

-Cory

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

[Jay Honeck]

> You mean 100 EGT, right?

Yep.

> - Run high enough (8500 is pretty good) so you can run WOT. Back it off
> about 1/4" of
> MP from full throttle. Cocking the throttle plate slightly like this
> helps mine.

I discovered this technique on my own, when I found it impossible to get the
six bars on my engine analyzer to line up at full throttle. To my surprise,
pulling the MP back JUST a smidge resulted in all six bars falling neatly in
line.

> YMMV... I suspect the big six on a Cherokee probably has worse fuel distro
> than the four in mine.

Yeah, I've spoken with a couple of O-540 experts, and they both say that 100
degrees apart is about as good as possible with the horrible fuel
distribution of a normally aspirated Lycoming six-cylinder engine.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[[email protected]]

In rec.aviation.owning Jay Honeck > wrote:
: > YMMV... I suspect the big six on a Cherokee probably has worse fuel distro
: > than the four in mine.

: Yeah, I've spoken with a couple of O-540 experts, and they both say that 100
: degrees apart is about as good as possible with the horrible fuel
: distribution of a normally aspirated Lycoming six-cylinder engine.
: --

I had a friend with an O-540 that built a fuel distribution "swirler" (like
the thing on TV). Basically, a ~4x4" piece of stainless steel. Cut 10 or so
pie-shaped wedges around a carb-outlet-sided circle scribed in it. Take those
pie-shaped wedges, bend them 70-80 degrees off the plate, and give them all a 45
degree twist. Put inline between the carb and bottom of the oil pan/intake. It got
his cylinders closer together in EGT. Of course doing such modifications on anything
other than an experimental engine/airframe would immediately cause it to crash, be
illegal, immoral, reckless, dangerous, irresponsible, as well as cause global
warming, world hunger, and eventually make the sun burn out.

-Cory


--

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

[TripFarmer]

But it was cheap gas, right? :o)


Trip

In article <m1She.81588$NU4.17695@attbi_s22>, says...
>
>Today on a long cross-country flight I experimented with the "lean-find"
>function on my JPI-700 EGT/CHT meter. As always, it told me to stop leaning
>when my fuel flow was right around 15 GPH. (This at 5500 feet, and 23
>squared.)
>
>Using the wisdom of the group, I kept pulling the mixture back until my
>FS-450 was showing around 13 gph fuel flow, watching the EGTs and CHTs like
>a hawk.
>
>Obviously everything did run hotter, but EGTs never topped 1550 degrees, and
>CHTs never topped 360 degrees. This is a tad hotter than I've been
>running, but the engine sounded fine, and all cylinders stabilized within
>100 degrees of each other -- which is as good as it gets on my normally
>aspirated O-540.
>
>Later, climbing to 8500 feet, we pulled it back to around 12 gph, with the
>same results. (We usually would run around 14 gph at that altitude.)
>
>So, perhaps I've been wasting gas for no good reason. Thanks to all who
>responded.
>--
>Jay Honeck
>Iowa City, IA
>Pathfinder N56993
>www.AlexisParkInn.com
>"Your Aviation Destination"
>
>

[Corky Scott]

On Mon, 16 May 2005 00:44:02 GMT, "Jay Honeck"
> wrote:

>Obviously everything did run hotter, but EGTs never topped 1550 degrees, and
>CHTs never topped 360 degrees. This is a tad hotter than I've been
>running, but the engine sounded fine, and all cylinders stabilized within
>100 degrees of each other -- which is as good as it gets on my normally
>aspirated O-540.

When you think about it for a minute Jay, it makes sense that the
cylinderheads cannot overheat when running lean of peak: There isn't
enough fuel in the mixture to overheat them.

Running LOP has it's consequences (less power developed), but
overheating and detonation aren't a worry.

Have you read Deakin's "Mixture Magic" column? It's EXTREMELY
comprehensive.

Corky Scott

[Jay Honeck]

> When you think about it for a minute Jay, it makes sense that the
> cylinderheads cannot overheat when running lean of peak: There isn't
> enough fuel in the mixture to overheat them.

???

I can easily get my EGTs over 1600 degrees, and my CHTs near (or over) 400
degrees by over-leaning. At some temperature (and I don't know what it is)
doesn't aluminum start to weaken?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[[email protected]]

In rec.aviation.owning Jay Honeck > wrote:
: I can easily get my EGTs over 1600 degrees, and my CHTs near (or over) 400
: degrees by over-leaning. At some temperature (and I don't know what it is)
: doesn't aluminum start to weaken?
: --

Yeah... about 250-300 degrees. Comforting, no?

Remember that EGTs are useful for *relative* measurements... not absolute.
What one engine/airframe/power setting combination produces for EGTs has very little
to do with another engine/airfram/power setting EGT. It's best used to find the peak,
and to see how even individual cylinders are by dithering around the peaks. Saying
one is at 1550 and another is at 1590 doesn't mean much... one may have a slightly
different position in the EG stream, more resistance inthe probe wiring, etc, etc...
run the mixture above and below to see where *each* peaks (below 75% of course).

Again... absolute EGT number is nothing to be concerned about (within reason,
but it's generally impossible to exceed reason with a certified engine). The EGT is
much more important, and running at or below 400 in cruise is considered acceptable.

-Cory


--

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

[George Patterson]

wrote:
>
> The EGT is
> much more important, and running at or below 400 in cruise is considered acceptable.

I'm sure you meant "CHT" in that sentence.

George Patterson
"Naked" means you ain't got no clothes on; "nekkid" means you ain't got
no clothes on - and are up to somethin'.

[Corky Scott]

On Tue, 17 May 2005 13:15:46 GMT, "Jay Honeck"
> wrote:

>> When you think about it for a minute Jay, it makes sense that the
>> cylinderheads cannot overheat when running lean of peak: There isn't
>> enough fuel in the mixture to overheat them.
>
>???
>
>I can easily get my EGTs over 1600 degrees, and my CHTs near (or over) 400
>degrees by over-leaning. At some temperature (and I don't know what it is)
>doesn't aluminum start to weaken?

Jay, have you read Deakin's article entitled "Mixture Magic"? If not,
find it here and read it through and through.

http://www.avweb.com/news/columns/182084-1.html

He also wrote four follow up columns entitled: "Where should I run my
engine" parts 1 through 4 in which he spells out in minute detail how
to adjust your prop and mixture for most efficient/safe flight on the
ground, in climb, at cruise and descending.

But if you look at the temperature chart (produced by Continental) and
what happens to the cylinderhead temps along with the EGT's as you
lean from full rich, you'll see two peaked curves BUT, and this is a
big but, **they don't peak together**.

The curves starts as low as they're going to be when the mixture is
full rich, and begin rising immediatly as you begin leaning out.

As the mixture reaches the stoichiometricly correct ratio, the engine
is producing the absolute maximum power it's capable of making (at
that altitude). Guess what? The maximum power and the hottest
cylinderhead temperatures occur at exactly the same time.

But at that point, the EGT's are still rising and will continue to
rise as you continue to lean, but the cylinderhead temps now start
DOWN as you lean below the peak temperature. Power also starts
dropping off as you continue to lean.

You really need to read the above article to get the proper
understanding because it takes pictures and charts to really explain
it and he has them all in this article.

But the point is, the charts show that as you continue to lean (in the
cruise condition), once you get the mixture to the point where it is
PAST PEAK, the temperatures begin to fall off. This is literally
because the mixture isn't good enough to produce the kind of heat and
pressure it can when the mixture is ideal. Less heat in the
combustion chamber, less heat to the cylinderheads. It's actually
more complicated than that but I'll let Mr. Deakin's words explain,
read the article.

When you say "but my temps go up when I lean", that's true ONLY while
the mixture is RICH OF PEAK. When you lean past that point, continued
leaning reduces engine temps for several reasons. Look at the chart,
it's Continental's own chart and it does not lie: Continued leaning
past the peak cylinderhead temperatures produces lower temperatures.
As Deakin points out, this chart works for all spark ignition four
stroke cycle engines regardless power output. Lean out the mixture
and that's what the engine temps will do.

It doesn't appear that you have leaned past peak in your adjustment of
the mixture, till now. You've approached peak, from the rich side of
the chart, but not below it. Your description of the temps you've
seen and your fuel burn tell us that.

It's important to understand that this technique produces the fastest
cruise for the least amount of fuel burned. You can set your engine
for a faster cruise but you'll burn more fuel. You can also set your
engine for longest range, but you'll be going very slowly.

Please note, for all who are reading this, Deakin does not believe
it's advisable to use this technique (LOP operation) without having
the necessary guages to monitor ALL the cylinder temps at once.

But Jay, you have the JPI guage that should allow you to at least
attempt to run the engine lean of peak, should you so desire.

Corky Scott

[[email protected]]

In rec.aviation.owning George Patterson > wrote:
: wrote:
: >
: > The EGT is
: > much more important, and running at or below 400 in cruise is considered acceptable.

: I'm sure you meant "CHT" in that sentence.

Ooops... my bad. PEBKAC
-Cory

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

[[email protected]]

In rec.aviation.owning Corky Scott > wrote:
: It doesn't appear that you have leaned past peak in your adjustment of
: the mixture, till now. You've approached peak, from the rich side of
: the chart, but not below it. Your description of the temps you've
: seen and your fuel burn tell us that.

: It's important to understand that this technique produces the fastest
: cruise for the least amount of fuel burned. You can set your engine
: for a faster cruise but you'll burn more fuel. You can also set your
: engine for longest range, but you'll be going very slowly.

: Please note, for all who are reading this, Deakin does not believe
: it's advisable to use this technique (LOP operation) without having
: the necessary guages to monitor ALL the cylinder temps at once.

: But Jay, you have the JPI guage that should allow you to at least
: attempt to run the engine lean of peak, should you so desire.

Instrumentation is the important key. If you look through the Lycoming FUD,
they say LOP is bad not because it's inherently flawed, just that most pilots are too
stupid to be able to do it safely and their planes aren't equipped. Remembering that
each cylinder is really its own entity as far as operation goes, individual
measurements are definately necessary. So long as each one is within the safe zone of
CHT (<400 in cruise), you should be fine at *ANY* mixture setting provided you're
below 75% power.

Unfortunately, you may be screwed before you even get going if the fuel
distribution is really bad on the O-540. I would set up a nice 60-65% cruise power
and lean the bejeepers out of it until it definately runs rough... maybe even more.
Watch where each jug peaks and see how mismatched they are. Not where they all get to
the same temp... just where each one starts to go back down again. On my O-360, I can
lean it to where the leanest cylinder is LOP, and the richest cylinder is at peak.
Since they're all running at a cooler CHT than running 50 ROP, it's still safe so long
as I'm at 75% or less. For a bit of "buffer zone" (especially since I run cargas),
I'll generally limit the power to 65-70%. My PA28 airframe is really starting to hit
the wall at 115 KTS or so anyway, so the additional 10% only buys 5 kts or so.

-Cory
--

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