LOP operation

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.

Howdy!

In article ,
kage demonstrated an amazing lack of reading
comprehension when he/she wrote:


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.

You didn't read a thing I wrote, apparently.

If you are running at, say, 70% power, you are spinning your fixed-pitch
prop at a particular RPM. At sufficient altitude, you may not be able to get
70% power, but that is irrelevant to the discussion.

It doesn't matter whether you are LOP or ROP. If you are getting X RPM,
you are getting Y% power. For a constant speed prop, the indicator is
different, but the concept is the same.

Of course, at high power levels, LOP is bad, but usually 75% power and under
is safe (from a detonation perspective).

To effectively operate LOP, you also need better control over the fuel
distribution from cylinder to cylinder -- particularly problematic with
carburetted engines. However, that doesn't change the essential fact that
operating LOP uses less fuel for a given power level than operating ROP.


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.

You didn't answer my question, and you left out your assertion that I
responded to. If your engine is capable of running LOP, you can manage
CHTs just fine.

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.

Ummm...now you leave out my response and continue with the bald assertions.
You made the claim -- now back it up, unless you are just making stuff up.

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

You didn't make that distinction. You simply asserted a century of ROP
operation without distinguishing particular engine types. I, once again,
note that LOP operations were essential to satisfactory operation of
round engines, especially the large ones, and may have been part of
stardard operating practices for other engine types as well. I don't
know all the answers, but I'm not claiming universal use of ROP as the
normal operating regime for all (aircraft) engines for the last century.

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?

CO is formed when there is more carbon (fuel) than oxygen -- the definition
of a "rich" mixture.

You didn't answer the part about how CO production has any real relation
to deciding whether to operate LOP or ROP. I guess that means you don't
have a reason for including that point in your list -- it was just padding.

Your ad hominem ("tree hugger") further reinforces that conclusion. You
resort to name calling when you can't make a substantive response.

Busted!

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.

Non sequitur. As in, that does not follow. Reread the response to your first
non-point.

Oh, I don't have charts available to me, but somehow I don't think they
really reference the mixture setting when telling you how much power you
can get at a given altitude, or how to get it. If you'd care to provide
a citation that we can all see to the contrary, I'll concede the points
where I am actually mistaken.

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.

I made as much of a point as you did, and I even admitted that I was using
cheap rhetorical devices. You just say "did too".

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.

What do you mean by "at altitude"? 10,000 feet? 20,000 feet?

I'm pretty sure you can get your normally aspirated light single up to 10k,
for many values of "light single".

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!

....and just because it's Usenet doesn't mean you get a free ride when you
make ridiculous claims and don't back them up. You still have not offered
any checkable facts, or any credentials that would tell us why we should
take your word on this.

I have shown (though you clearly ignored it) how more than one mixture
setting can produce the same power level, but you continue to assert
something else. You gave us a laundry list of "reasons" why LOP was a
bad thing but offered no reason for us to take your word for it. When
called on that, you simply continue to repeat, deny, and change the
subject.

Get some experience and check back in.

You first.

yours,
Michael

--
Michael and MJ Houghton | Herveus d'Ormonde and Megan O'Donnelly
| White Wolf and the Phoenix
Bowie, MD, USA | Tablet and Inkle bands, and other stuff
| http://www.radix.net/~herveus/