Scientific Data on Engine Operations

"Michael" wrote in message
oups.com...
Why? Be specific and technical.

Where is your long-term field study comparing LOP and ROP operations?

How many engines have been monitored in service from start to overhaul,
under what conditions, and for how long? Have you shown a
statistically significant difference in MTBF, service life, or cost of
maintenance? That's really the only way to cover all bases. Sometimes
this is not practical, but lacking a long term field study, you at
least need a reasonable model. A compelling model would address the
following issues, as a minimum:

It's been done.

What are your parameters to asess engine roughness in normal LOP and
ROP operations? How do you model the imperfections caused by pilot
technique? Do you have amplitude and frequency data on engine
vibration at various mixture settings? What kind of sensors did you
use?

It's been done.


Do you have long term operational data or at least a model showing the
long term behaviour of the engine mounts, bearings, cases, crankshaft,
etc. under the vibration conditions?

It's been done.

Without long-term operational
data, I would expect at least an FEA.

Five years of data.

Do you have any information at all on the differences in combustion
end-products in excess-air vs. excess-fuel combustion reactions?

Yes.

I can
assure you they are differrent. Are any of the combustion products
harmful to the engine components long-term? Do any pose corrosion
issues when the aircraft is not flown for several days or weeks, as
commonly happens with private planes?

Non-sequitur.


How about that big mixture pull - it takes the mixture through peak.
What is the effect of this transition on the crankshaft? Some analysis
of this issue was done in the 1940's, using the limited available tools
- but only for radial engines, which have significantly different
crankshaft designs. For that matter, about the only large base of
operational data in the LOP regime comes from radial engines - which
are different - using 1940's and 1950's fuels which were significantly
different than what you're burning now.

Bull****.


I'm sure given time I could think of other issues.

The main arguments for LOP operation are short-term economic ones -
less plug fouling, lower fuel burn.

Lower internal pressures, etc. All have been hypothesized, tested...

These are pretty compelling. As
for effect on TBO and general engine longevity, there has been much
hype and no compelling evidence.

Bull****.

BTW - to answer your other question - I run the R&D group for a major
manufacturer of industrial instrumentation. So yes, this is pretty
much right up my alley.

What sort of industry? Baed on that your only angle to comment on is about
the test bed at http://www.engineteststand.com

Not doing tests? A 64 point analysis tool, doing thousands of readings a
second?

I'm seeing something here besides naiveté on your part.

I'm claiming "Bull****" on your part.

I'm seeing something here besides naivet=E9 on your part.

Ah, of course - anyone who disagrees with you must have ulterior
motives. Wrong again. I am NOT in the aviation industry (we provide
instrumentation to petroleum, refining, municipal water and wastewater,
chemical, metals, mining and dredging, and other industries - but not
aviation) and the aircraft I own, I routinely operate LOP. I'm simply
not blinded by the hype as you are.

I'm claiming "Bull****" on your part.

You're welcome to your opinion. You response pretty much demonstrates
that it's not an informed opinion.

I've been technical and specific. You haven't. If you expect to be
taken seriously, go back through your response and provide links where
you say it's been done, and an explanation where you call bull****. Be
technical and specific.

Michael

"Michael" wrote in message
oups.com...
I'm seeing something here besides naiveté on your part.

NOTE: Seeing that the issue here has morphed from "scientific methods in the
lab" to "LOP being hype", I'll address the latter.

Michael implies that LOP is untested outside a laboratory. Much has been
informal field work. OTOH, much has been done in the "lab" -
http://www.engineteststand.com/ (You can watch in real time).

Ah, of course - anyone who disagrees with you must have ulterior
motives. Wrong again. I am NOT in the aviation industry (we provide
instrumentation to petroleum, refining, municipal water and wastewater,
chemical, metals, mining and dredging, and other industries

And that relates...how?

- but not
aviation)

So your qualifications do NOT correspond.

and the aircraft I own, I routinely operate LOP.
I'm simply
not blinded by the hype

CHRIST-ON-A-BIKE, _why_? It's all HYPE, remember?
as you are.

Oh, anyone who disagrees with you is blinded by hype. No, but your full of
it (or of yourself).

I'm claiming "Bull****" on your part.
You're welcome to your opinion. You response pretty much demonstrates
that it's not an informed opinion.

Yours say nothing either. You make spurious claims of engineering expertise
that has virtually nothing to do with the issue.

Cut the attempts at intimidation, I've been intimadted by some real pros and
you're just a whelp compared to them.

I've been technical and specific.

Bull****. You made numerous unsubstantiated assertions, not to mention
claims of expertise that are worthless.

Let's see what you've snipped:

:Where is your long-term field study comparing LOP and ROP operations?

Deakin's "Engine Series" provides:
http://www.avweb.com/news/columns/182146-1.html

See any of them about the combustion event and TDC.

:How many engines have been monitored in service from start to overhaul,
:under what conditions, and for how long? Have you shown a
:statistically significant difference in MTBF, service life, or cost of
:maintenance? That's really the only way to cover all bases. Sometimes
:this is not practical, but lacking a long term field study, you at
:least need a reasonable model.

See above, plus the history of TOH's...

: A compelling model would address the
: following issues, as a minimum:
: What are your parameters to asess engine roughness in normal LOP and
: ROP operations?

As mentioned earlier:
"These subjective reports were confirmed recently when Chadwick-Helmuth
spent several days running tests on a 1993 Beech F33A instrumented with one
of C-H's latest state-of-the-art vibration analyzers hooked to multiple
accelerometers and vibration transducers. Tests were flown at a wide range
of power settings and mixtures using a set of standard TCM nozzles, then
repeated after GAMIjectors were installed. The results indicated that the
GAMIjectors reduced vibration levels at the 2nd order frequency and at the
low 1/3rd order frequency by 60% to 80%.

I guess you conveniently missed that one, huh?

:How do you model the imperfections caused by pilot
:technique? Do you have amplitude and frequency data on engine
:vibration at various mixture settings? What kind of sensors did you
:use?

http://www.engineteststand.com/


o you have long term operational data or at least a model showing the
:long term behaviour of the engine mounts, bearings, cases, crankshaft,
:etc. under the vibration conditions? Without long-term operational
:data, I would expect at least an FEA.

http://www.engineteststand.com/ (Been running for several years).

o you have any information at all on the differences in combustion
:end-products in excess-air vs. excess-fuel combustion reactions? I can
:assure you they are differrent.

??? Nice tangent there!!!

: Are any of the combustion products
:harmful to the engine components long-term?

Like Lead Oxybromide? :~)

o any pose corrosion
:issues when the aircraft is not flown for several days or weeks, as
:commonly happens with private planes?

Not that what you ask has a damn thing to do with it, but, since you aren't
being specific, neither will I, so you can dig out the specifics:

http://www.avweb.com/news/columns/182132-1.html

http://www.avweb.com/news/columns/182149-1.html

:How about that big mixture pull - it takes the mixture through peak.
:What is the effect of this transition on the crankshaft?

http://www.avweb.com/news/columns/182084-1.html (Half way down...you can
correlate this to a crankshft, can't you?)

: Some analysis
f this issue was done in the 1940's, using the limited available tools
:- but only for radial engines, which have significantly different
:crankshaft designs. For that matter, about the only large base of
perational data in the LOP regime comes from radial engines - which
:are different - using 1940's and 1950's fuels which were significantly
:different than what you're burning now.



Wow!! That's real specific. Methodological, but NOT ONE PIECE OF DATA.

You haven't. If you expect to be
taken seriously, go back through your response and provide links where
you say it's been done, and an explanation where you call bull****. Be
technical and specific.

I fully expect, based on your response to questions of your assertions,
that's you'll provide a classic example of evasion.

http://www.avweb.com/news/reviews/182558-1.html (Data graphs
specifically...or are those faked?)

http://www.avweb.com/cgi-bin/udt/im....ry.id=1825 31
(data set one-fourth of the way down..or is that just fake hype?)


Charts, graphs, explanations all over the place in these.

http://www.avweb.com/news/columns/182155-1.html (Data through out)

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


--------

Michael

I'd really like to flesh this all out, and have the benefit of some real
expertise, for my benefit as well as the community. I suspect that, as
mentioned, Michael's not making much more than farts in the wind.

I also find a disconnect between the terms "science" and "engineering". Yes,
doing full blown lab test would be nice. Some of the data has been done in
the lab, a lab far more advanced than anything TCM Lycoming has ever done.
One tenant about science or engineering is that data must not contradict
other data. It doesn't.

Is all this as formal as a pristine laboratory? Hell no. Does it need to be?
Not hardly. I guess Lavoisier's and Priestly's work was worthless since they
didn't work in a formal lab. :~)

One of the defining characteristics of humans is the ability to
conceptualize and abstract. Try it.

(This is twice, now, that you've challenged without providing an ounce of
data. I expect some more SPIN...)


Matt
---------------------
Matthew W. Barrow, SCCE
Site-Fill Homes, LLC.
Montrose, CO

and the aircraft I own, I routinely operate LOP.
I'm simply
not blinded by the hype

CHRIST-ON-A-BIKE, _why_? It's all HYPE, remember?

Because LOP saves fuel and keeps plugs clean. That much is proven. It
is a fact that lower combustion pressures are also proven - but how
this correlates to long term engine longevity is unknown.

Where is your long-term field study comparing LOP and ROP operations?
Deakin's "Engine Series" provides:
http://www.avweb.com/news/columns/182146-1.html
See any of them about the combustion event and TDC.

None of that says ANYTHING about longevity - at least nothing provable.
Yes, the peak pressure is lower. So? Does the difference impact
longevity? Where is your model? Absent that, where is your long term
controlled field study?

: What are your parameters to asess engine roughness in normal LOP and
: ROP operations?

As mentioned earlier:
"These subjective reports were confirmed recently when Chadwick-Helmuth
spent several days running tests on a 1993 Beech F33A instrumented with one
of C-H's latest state-of-the-art vibration analyzers hooked to multiple
accelerometers and vibration transducers. Tests were flown at a wide range
of power settings and mixtures using a set of standard TCM nozzles, then
repeated after GAMIjectors were installed. The results indicated that the
GAMIjectors reduced vibration levels at the 2nd order frequency and at the
low 1/3rd order frequency by 60% to 80%.

I guess you conveniently missed that one, huh?

Not at all. I never said that GAMIjectors do not reduce vibration at
equivalent operating conditions. The test you refer to is a validation
of a product, not an operating regime. It shows that regardless of
what you do in terms of operating a given TCM engine (and note - this
is ONE engine) it does better with GAMI's. No argument. The question
is whether it does better LOP or ROP with the same injectors, and this
test does not give you that information.

:How do you model the imperfections caused by pilot
:technique? Do you have amplitude and frequency data on engine
:vibration at various mixture settings? What kind of sensors did you
:use?
http://www.engineteststand.com/

Oh no you don't. Be technical and specific. What is the model? Where
is it specifically? What assumptions does it make?

o you have long term operational data or at least a model showing the
:long term behaviour of the engine mounts, bearings, cases, crankshaft,
:etc. under the vibration conditions? Without long-term operational
:data, I would expect at least an FEA.
http://www.engineteststand.com/ (Been running for several years).

How many engines? How many installations? And what kind? Be technical
and specific. Explain why that one given installation should be
considered proof for all (or even most).

o you have any information at all on the differences in combustion
:end-products in excess-air vs. excess-fuel combustion reactions? I can
:assure you they are differrent.
??? Nice tangent there!!!

Not a tangent at all. Since corrosion takes down a lot more engines
than wear on personal aircraft, it's a major issue.

: Are any of the combustion products
:harmful to the engine components long-term?
Like Lead Oxybromide? :~)

Maybe. Maybe others. See, unless you have a statistically significant
sample of engines being run under controlled conditiions long enough to
establish MTBF, you don't really know WHAT the real issue is, so it's
your responsibility to cover all the bases if you want to claim
anything resembling compelling evidence.

Wow!! That's real specific. Methodological, but NOT ONE PIECE OF DATA.

No, there isn't one piece of data. But then I'm not the one claiming
compelling evidence exists, one way or the other. I in fact claim just
the opposite - that no compelling evidence exists one way or the other.
There are some very compelling short-term reasons to operate LOP (save
fuel, don't have to clean the spark plugs as often) and no real
evidence one way or the other what happens in the long term

The people who claim LOP is harmful in the long term are whistling in
the wind too.

I fully expect, based on your response to questions of your assertions,
that's you'll provide a classic example of evasion.
http://www.avweb.com/news/reviews/182558-1.html (Data graphs
specifically...or are those faked?)

Not faked - just not relevant. They show no long term trends in
operation. Where are your graphs showing maintenance costs year by
year? Failures year by year?

This is twice, now, that you've challenged without providing an ounce of
data. I expect some more SPIN...

You're really not getting it. I have NO data. Anywhere. I don't
think it exists. What you've shown is data all right - but not data
you can use to project MTBF or TBO or maintenance cost.

The number we're going for is this:

An engine operated LOP (making certain assumptions about how it will be
operated) will have an hourly operating cost of x% (less/more) than an
identical engine operated ROP (making the same assumptions about the
pilot's ability to consistently control the engine, and if the LOP
engine has GAMI's, so does the ROP engine) excluding fuel (where the
case has already been made quite adequately) but including parts
replacement, overhaul, etc.

Now show me what x is, how it was derived, and what assumptions were
involved.

Michael

"Michael" wrote in message
ups.com...
and the aircraft I own, I routinely operate LOP.
I'm simply
not blinded by the hype

CHRIST-ON-A-BIKE, _why_? It's all HYPE, remember?

Because LOP saves fuel and keeps plugs clean. That much is proven. It
is a fact that lower combustion pressures are also proven - but how
this correlates to long term engine longevity is unknown.

DUH!!! And you're an engineer? HAHAHAHAHAHAH...

ALB

"Matt Barrow" wrote:
CHRIST-ON-A-BIKE, _why_? It's all HYPE, remember?

Because LOP saves fuel and keeps plugs clean. That much is proven. It
is a fact that lower combustion pressures are also proven - but how
this correlates to long term engine longevity is unknown.

DUH!!! And you're an engineer? HAHAHAHAHAHAH...

Evasion by ad hominem noted.

ALB

Running away noted.

On Wed, 20 Jul 2005 07:25:09 -0700, Matt Barrow wrote:


"Michael" wrote in message
ups.com...
and the aircraft I own, I routinely operate LOP.
I'm simply
not blinded by the hype

CHRIST-ON-A-BIKE, _why_? It's all HYPE, remember?

Because LOP saves fuel and keeps plugs clean. That much is proven. It
is a fact that lower combustion pressures are also proven - but how
this correlates to long term engine longevity is unknown.

DUH!!! And you're an engineer? HAHAHAHAHAHAH...

Don't forget that there is no correlation between reduced vibration and
increased longevity.... Hehe.... Oh wait...that only validates a product
(and its principles), not the principal it self. Hmmm...

On Sat, 16 Jul 2005 02:51:27 +0000, bill hunter wrote:

[snip]
I change altitudes a lot, and tend to fly high when weather permits. I
also have a turbo arrow with a very sensitive throttle that needs to be
adjusted continuously during climbs and decent. I don't need the
aggravation of having to adjust the mixture 3 times as much because I
was LOP. I know during the 2000 hours I would eventually get distracted
in busy airspace, and end up running too close to peek during a cruise
climb.


I thought LOP was not recommended for turbo applications?

On Fri, 15 Jul 2005 11:27:54 -0700, Michael wrote:

The extra vibration occurs only if you don't have proper fuel
distribution LOP
[snip]

Of course all the piston airliners routinely ran LOP - but it's
important to remember that over the course of its life, the cost of
fuel the engine burns is significantly higher than the cost of the
overhaul - and thus LOP operation, which can easily save 10-15% for the
same power and speed, can be economically advantageous even if it does
measurably shorten engine life.

Michael

This seems like one of the most straight forward and reasonable statements
you've made thus far. That's a good point. A very good point. Have
anything which validates that's the real reason they ran LOP?

"Greg Copeland" wrote in message
news
On Sat, 16 Jul 2005 02:51:27 +0000, bill hunter wrote:

[snip]
I change altitudes a lot, and tend to fly high when weather permits. I
also have a turbo arrow with a very sensitive throttle that needs to be
adjusted continuously during climbs and decent. I don't need the
aggravation of having to adjust the mixture 3 times as much because I
was LOP. I know during the 2000 hours I would eventually get distracted
in busy airspace, and end up running too close to peek during a cruise
climb.


I thought LOP was not recommended for turbo applications?


See Deakin's series, "Those Fire-Breathing Turbo's", parts 1-6.

http://www.avweb.com/news/columns/182146-1.html