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

("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

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"

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.

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.

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

"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!! :~)

("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

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

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

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