LOP operation

On Wed, 14 Apr 2004 22:36:41 -0700, "kage"
wrote:

Even John Deakin burned out a set of
Continental cylinders in 500 hours LOP in his Bonanza. And their highly
touted fuel savings are, for the most part, due to a decrease in speed. You
know, all that drag increase with V squared.

I'd hesitate to speak for Mr. Deakin but I'd venture that he'd
disagree violently that running lean of peak burned out his cylinders.
Since running lean of peak results in low temperatures and less gas
being burned, how exactly did they get burned out?

To demonstrate that running lean of peak does not necessarily mean a
lost of power, his "Mixture Magic" column showed a color photo of an
instrument panel of a Cessna 410 running one engine ROP and the other
LOP. Both engines were producing exactly the same power but at
different manifold pressures. The LOP engine was using less fuel and
was running at lower CHT temps. How is that bad?

CHTs are just fine ROP.

Actually they aren't, if you set the engine according to the POH.
Running at 75% or 80% power and set 50 degrees ROP, the CHT's run
above 400 degrees. These are figures that come from Lycoming and
Continental. And yet over 400 degrees is where aluminum begins to
loose strength. Deakin also was able to demonstrate that at certain
POH dictated ROP settings, the cylinders actually distorted from the
heat and began to scuff the pistons. This was during flight testing
with several proprietary probes installed in his engine which could
read what was happening in areas away from the cylinderhead probe.
While these probes were showing alarming increases in heat, the
cylinderhead readings read normal. He had to terminate the testing at
those settings because the readings at the bases of the cylinders were
rapidly rising, indicating that the pistons were beginning to scuff.

Engines run clean enough ROP.
Engine stresses have been doing just fine now for 100 years ROP.
CO is not a problem in maintained exhaust systems.
Airplanes fly faster ROP.

Not necessarily. Same rpm, same airspeed but higher manifold pressure
at the LOP settings equals the same cruise speed. Yes, if you want to
fly at best power, you should be running ROP.

Even the LOP diehards admit engines run smoother ROP.
Gamis have more value in a turbocharged engine.

Once again, not necessarily. Once the GAMI injectors are installed,
Deakin has been able to lean right to the point of having the engine
quit due to a mixture too lean to fire, without any roughness at all.
If there's roughness then the injectors are not matched properly.

Corky Scott

For a given power setting, in general (module altitude effects), there
are two mixture settings to give that power. One ROP, the other LOP.
If you run at, say, 70% power, your airspeed is going to be fixed at
a particular level, assuming stable, level flight. If you run LOP,
you run less fuel through the engine, and you burn all of it up. If
you turn ROP, you use some of it to cool the engine -- using more
fuel than LOP operation. All this for the same speed.

Only at very low altitudes. Get YOUR facts straight. LOP is worthless at
altitude because you simply cannot push enough gas through the engine to
develop any meaningful horsepower, unless, like I said, you are
turbocharged.


What CHT level do you think is "just fine"? How does this argue
in favor of ROP?

For decades we were running ROP and there were no casualties from high CHTs.
I ran several IO520s to overhaul in the 70's without any premature cylinder
pulls.

Engines run clean enough ROP.

Your data is unsupported, not mine. There are, and never were prolems with
Cont/Lyc running "dirty." Where is YOUR data to assert this. You are pulling
this out of thin air. Lack of experience and GAMI propaganda here.

Engine stresses have been doing just fine now for 100 years ROP.

Oh? Have you ever examined the operations of round engines,
especially the bigger things like R-3350s? IIRC, LOP operations
were mandatory to get satisfactory performance and engine life.

So what? We are talking Walter here, GAMI----remember. They don't make
injectors for R-3350s

CO is not a problem in maintained exhaust systems.

What does that have to do with the decision? LOP makes less CO;
isn't that a positive?

No. Not necessarily. Where is your data, as you like to say, that this is
positive? You aren't some tree hugger are you?

Airplanes fly faster ROP.

That claim is especially brown and smelly, given the orifice it
was pulled from. See discussion above. Speed is all about power
levels.

Impossible to pull sufficient power at any reasonable higher altitude
without a turbo. Try running LOP at 10,000 ft. Look at your charts(worthless
LOP) at 10,000 and show me how much power/speed you are making.

Even the LOP diehards admit engines run smoother ROP.

As opposed to the ROP blowhards who can't abide admitting they might
be wrong? See! I can use cheap rhetorical devices, too! Would you
care to try a logical approach, or are you just interested in being
fanatical?

Again you don't even make a point. Smoother is smoother, period.

Gamis have more value in a turbocharged engine.

What does this have to do with deciding to operate LOP? Or are you
just trying to obfuscate with more irrelevancies?

Turbo engines benefit from LOP because they can still pull the necessary
power to run at altitude. You really should get some facts straight about
available power at altitude LOP.

And, I have plenty of dirt under my nails, thank you for asking.

Do you have real qualifications to back up your amazing assertions?
How about real data? Sound logical reasoning?

This is Usenet. You have shown me NO logical reasoning. Only GAMI claims.
Cooler, cleaner, less stress----irrelevant!

Get some experience and check back in.

wrote in message
...
On Wed, 14 Apr 2004 22:36:41 -0700, "kage"
wrote:

To demonstrate that running lean of peak does not necessarily mean a
lost of power, his "Mixture Magic" column showed a color photo of an
instrument panel of a Cessna 410 running one engine ROP and the other
LOP. Both engines were producing exactly the same power but at
different manifold pressures. The LOP engine was using less fuel and
was running at lower CHT temps. How is that bad?

Uh, what's a Cessna 410? Is it the predecessor to the 411 with an TCM
GTSIO-520-M engine?

Allen

On Thu, 15 Apr 2004 19:32:39 GMT, "Allen"
wrote:

Uh, what's a Cessna 410? Is it the predecessor to the 411 with an TCM
GTSIO-520-M engine?

Allen

Sorry, working on memory from the article. It was a Cessna 414. See
http://www.avweb.com/news/columns/182084-1.html

Corky Scott

If you lean slowly in your 172N to rough, then slowly enrich until just
smooth -- where do you wind up with regard to EGT?



I'm going to try and trace my thought processes back here because I think a
lot of 4 banger, fixed pitch pilots are still flying the way I have at
various times.

I started out without an EGT knowing only that leaner was hotter, too lean
made the engine rough, and too hot would burn the valves. I also didn't
really believe that the engine would restart if I leaned so much that it
quit. A CFI would have done me a big favor by showing me that you could
lean it until it was producing almost no power and then bring it back again.

So, I would carefully turn the mixture listening intently for the slightest
change in engine sound (Is that rough?) I was afraid to ever lean it enough
to learn what rough actually sounded like. Carefully doesn't mean slowly.
New pilots tend to do everything like this quickly because they look up to
find themselves 200 feet off altitude if they don't. The care was in
jumping like a rabbit back to richer from the slightest burble in the
exhaust sound. I know from later flying with the EGT that this method was
putting me about 50 - 75 ROP.

After I took over as maintenance officer, I had the EGT probe tested and it
was working. The gauge had never been adjusted so it was off scale most of
the time. I leaned and looked at the gauge and it didn't seem to react so I
just ignored it for another couple of years.

Then I learned two new things. You can't hurt the engine at 75% power with
any mixture setting and these engines, which were not designed to burn
100LL, need to be really leaned to avoid plug and valve stem fouling. This
prompted me to dig out and read through the stuff that came with the Alcor
EGT gauge. I'd heard about LOP by this time but thought it was only for
GAMI customers. I also went out and calibrated the EGT according to the POH
supplement which, along with some patience, suddenly made it a usable
instrument. I was still focused on plug fouling so I leaned to peak and
then back 50 degrees to cover the spread in FA ratios and make sure none of
the uninstrumented cylinders were in the "dangerous" LOP zone. So, I was
still flying the same way but with an EGT gauge.

The information that carb heat helps to even out mixture distribution was
coming to light just about the time our plane went down for a three month
refit so it was a frustrating winter. Here's what I know now.

If you keep leaning our engine with carb heat off, it does not get steadily
rougher from the first change in engine sound that used to spook me into
giving the mixture knob a couple turns back. You can keep going to peak and
a little beyond with little change. Jumping back from the first flaw in
smoothness was the mistake I'd been making for years. It's noticeably rough
by peak though. Lean it really smooth again and you'll wind up about 50
ROP.

Now put on the carb heat and forget about roughness, lean it until it really
sags and slowly turn the mixture in. With WOT or close to it, the engine
will settle down to about the same power output and roughness as it had at
25 - 50 ROP without carb heat but CHT will be 15 - 25 degrees lower. With
the ROP operation, the throttle would be pulled back farther to keep the
power in the 60 - 75% range but RPM, not throttle position is the measure of
power output. (For fixed pitch, anyway).

This is clearly only going to work in the lower half of our 172's service
ceiling but that's where a lot of our flying is done. There are also a lot
of subtle factors that effect mixture distribution. It would not surprise
me a bit if another O-320 H2AD in a 172N didn't have good enough mixture
distribution to make this work.

I also don't think you can do it cookbook style. I suspect you have to go
through the fiddling stage, trying different amounts of carb heat and
learning the way the engine sounds and reacts at different points. After
that, it should be easier.

I'm still learning about it which is why I'm curious what kind of experience
other simple engine fliers have if they try it (as opposed to just
pontificating about it).


--
Roger Long

wrote in message
...
On Wed, 14 Apr 2004 22:36:41 -0700, "kage"
wrote:

Even John Deakin burned out a set of
Continental cylinders in 500 hours LOP in his Bonanza. And their highly
touted fuel savings are, for the most part, due to a decrease in speed.
You
know, all that drag increase with V squared.

I'd hesitate to speak for Mr. Deakin but I'd venture that he'd
disagree violently that running lean of peak burned out his cylinders.
Since running lean of peak results in low temperatures and less gas
being burned, how exactly did they get burned out?

I addressed Kage's comments to Deakin and he responded in a private email.
You're completely right that Deakin disagrees...well, vehemently.

On Thu, 15 Apr 2004 22:34:24 GMT, "Roger Long"
om wrote:

If you lean slowly in your 172N to rough, then slowly enrich until just
smooth -- where do you wind up with regard to EGT?



I'm going to try and trace my thought processes back here because I think a
lot of 4 banger, fixed pitch pilots are still flying the way I have at
various times.


I also don't think you can do it cookbook style. I suspect you have to go
through the fiddling stage, trying different amounts of carb heat and
learning the way the engine sounds and reacts at different points. After
that, it should be easier.

I'm still learning about it which is why I'm curious what kind of experience
other simple engine fliers have if they try it (as opposed to just
pontificating about it).

Interesting and educational story. It is clear that, in your engine,
following Lycoming's recommendations does result in running 50°F ROP. That
may not be what L intended, but that surely seems to be the result.

I, too, was never taught to properly lean. And I probably didn't really
learn to do it correctly until I'd owned my own airplane for five or ten
years (or maybe longer). There were a number of Mooniacs who were
recommending leaning to 50° rich for best power. In retrospect, although I
probably was aiming for that, I was likely a lot richer due to making the
adjustments too quickly.

But my "mature" Mooney would never show cruise CHT's much above 325°; and
my engine problems necessitating early O/H have not been related to
leaning.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

If you recall, I said Deakin burned out his cylinders despite his GAMIs, not
because of them. GAMIs will never correct Continentals poor build quality
and crummy warranty service.

All the hype that GAMI puts out about cooler, cleaner, peak pressure etc.
doesn't do a thing for longevity of junk. See Deakin's cylinders, for
example. And if you need to privately discuss this with Deakin, at least get
your "facts" straight. Plus, go get some aviation experience so you can have
something to offer Usenet besides poor manners.

Best,

Get a brain and start using it.
"Tom Sixkiller" wrote in message
...

wrote in message
...
On Wed, 14 Apr 2004 22:36:41 -0700, "kage"
wrote:

Even John Deakin burned out a set of
Continental cylinders in 500 hours LOP in his Bonanza. And their highly
touted fuel savings are, for the most part, due to a decrease in speed.
You
know, all that drag increase with V squared.

I'd hesitate to speak for Mr. Deakin but I'd venture that he'd
disagree violently that running lean of peak burned out his cylinders.
Since running lean of peak results in low temperatures and less gas
being burned, how exactly did they get burned out?

I addressed Kage's comments to Deakin and he responded in a private email.
You're completely right that Deakin disagrees...well, vehemently.

Hey Charles,

If your reading is better than your Cessna model number knowledge, be aware
that I've always maintained GAMIs and Turbo engines are a good deal. A
Cessna 410(sic) is turbocharged. For normally aspirated engines, however,
their benefit is greatly diminished by the FACT that LOP reduces power,
especially where you need it most---at cruise at altitude.

*****Once again, not necessarily. Once the GAMI injectors are installed,
Deakin has been able to lean right to the point of having the engine
quit due to a mixture too lean to fire, without any roughness at all.
If there's roughness then the injectors are not matched properly.*****

That is just simply incorrect. There is roughness that anyone, including
Deakin and Braly notice. It has nothing to do with the injectors being
mismatched. It has everything to do with the need for the engine's timing to
be adjustable. LOP REQUIRES the timing to be further advanced. GAMI knows
this, and is the reason they are developing their Prism system of engine
management.

Best,




And
wrote in message
...
On Wed, 14 Apr 2004 22:36:41 -0700, "kage"
wrote:

Even John Deakin burned out a set of
Continental cylinders in 500 hours LOP in his Bonanza. And their highly
touted fuel savings are, for the most part, due to a decrease in speed.
You
know, all that drag increase with V squared.

I'd hesitate to speak for Mr. Deakin but I'd venture that he'd
disagree violently that running lean of peak burned out his cylinders.
Since running lean of peak results in low temperatures and less gas
being burned, how exactly did they get burned out?

To demonstrate that running lean of peak does not necessarily mean a
lost of power, his "Mixture Magic" column showed a color photo of an
instrument panel of a Cessna 410 running one engine ROP and the other
LOP. Both engines were producing exactly the same power but at
different manifold pressures. The LOP engine was using less fuel and
was running at lower CHT temps. How is that bad?

CHTs are just fine ROP.

Actually they aren't, if you set the engine according to the POH.
Running at 75% or 80% power and set 50 degrees ROP, the CHT's run
above 400 degrees. These are figures that come from Lycoming and
Continental. And yet over 400 degrees is where aluminum begins to
loose strength. Deakin also was able to demonstrate that at certain
POH dictated ROP settings, the cylinders actually distorted from the
heat and began to scuff the pistons. This was during flight testing
with several proprietary probes installed in his engine which could
read what was happening in areas away from the cylinderhead probe.
While these probes were showing alarming increases in heat, the
cylinderhead readings read normal. He had to terminate the testing at
those settings because the readings at the bases of the cylinders were
rapidly rising, indicating that the pistons were beginning to scuff.

Engines run clean enough ROP.
Engine stresses have been doing just fine now for 100 years ROP.
CO is not a problem in maintained exhaust systems.
Airplanes fly faster ROP.

Not necessarily. Same rpm, same airspeed but higher manifold pressure
at the LOP settings equals the same cruise speed. Yes, if you want to
fly at best power, you should be running ROP.

Even the LOP diehards admit engines run smoother ROP.
Gamis have more value in a turbocharged engine.

Once again, not necessarily. Once the GAMI injectors are installed,
Deakin has been able to lean right to the point of having the engine
quit due to a mixture too lean to fire, without any roughness at all.
If there's roughness then the injectors are not matched properly.

Corky Scott

Hi Corky,

Even John Deakin burned out a set of
Continental cylinders in 500 hours LOP in his Bonanza. And their
highly
touted fuel savings are, for the most part, due to a decrease in
speed. You
know, all that drag increase with V squared.

I'd hesitate to speak for Mr. Deakin but I'd venture that he'd
disagree violently that running lean of peak burned out his
cylinders.

Even if it did - Mr. Deakin is one of the key people in developing LOP
operations for today's GA Piston Aircraft. I guess he did experiment a
bit with it before getting it right.

However I fully agree: If done right running LOP puts less (thermal)
stress on the engine and is certainly not going to "burn out"
cylinders.

regards,
Friedrich

--
please remove entfernen from my adress for personal email