Constant speed props

I also highly recommend John C Eckalbar's books

FLYING THE BEECH BONANZA

and

FLYING HIGH PERFORMANCE SINGLES AND TWINS

These books will describe the relationship between aircraft weight and
the various V-speeds you should know when you fly.

Ge,

here's another vote for the engine management columns by John Deakin at
www.avweb.com

--
Thomas Borchert (EDDH)

I think Deakin is worth reading, but some of what he says should be taken
with a grain of salt. His columns are mostly based on experiments with his
own highly modified Bonanza, a few high performance radial engines, and some
theory. In fact, a careful reading of his columns will show no test data for
the most common engine and propeller combinations in use today. The reasons
for this are fairly simple -- few airplanes have the instrumentation that
Deakin needs to test his theories. This is why Deakin's theories for running
lean of peak remain a minority view. Granted, it is a very noisy minority,
but remember that it is also a small minority. I think they have a point.
They may even be right. But they don't have nearly the evidence that they
think they have.

Deakin's remarks are mostly pertinent to running TCM engines, which are much
different than engines from other manufacturers. Not to put too fine a point
on it, some TCM engines are the only ones I know of that so consistently
develop cracks that the most part of an annual inspection basically consists
of measuring and cataloging the spread of these cracks. The engine used in
the early 70's Cessna T206 rarely made it to its 1400 hour TBO, for example.

Barring solid data to the contrary (and Deakin, remember, does not give you
solid data -- he only appears to do that), your airplane should be operated
in accordance with the manufacturer's recommendations. This will ensure that
you maintain your insurance coverage, if nothing else.

Keeping all that in mind, Deakin's columns are still probably the best
exposition on how to use a constant speed propeller. You will note right
away that everything is about power and performance. A fair number of people
think it is also about fuel economy, but that is at best a secondary
consideration. Fuel economy is a natural result of getting maximum power for
your fuel burn, but if that were really the goal there would be no
turbocharged engines.

"C J Campbell" wrote in message
...
I think Deakin is worth reading, but some of what he says should be taken
with a grain of salt. His columns are mostly based on experiments with his
own highly modified Bonanza, a few high performance radial engines, and
some
theory. In fact, a careful reading of his columns will show no test data
for
the most common engine and propeller combinations in use today.

You've not read hiscolumns about the test beds they've run at GAMI?


The reasons
for this are fairly simple -- few airplanes have the instrumentation that
Deakin needs to test his theories. This is why Deakin's theories for
running
lean of peak remain a minority view. Granted, it is a very noisy minority,
but remember that it is also a small minority. I think they have a point.
They may even be right. But they don't have nearly the evidence that they
think they have.

See above.

Deakin's remarks are mostly pertinent to running TCM engines, which are
much
different than engines from other manufacturers.

I bellieve they run Lycoming on the test bed as well, everything from
pipsqueaks to the big 540's.

Not to put too fine a point
on it, some TCM engines are the only ones I know of that so consistently
develop cracks that the most part of an annual inspection basically
consists
of measuring and cataloging the spread of these cracks. The engine used in
the early 70's Cessna T206 rarely made it to its 1400 hour TBO, for
example.

Barring solid data to the contrary (and Deakin, remember, does not give
you
solid data -- he only appears to do that), your airplane should be
operated
in accordance with the manufacturer's recommendations. This will ensure
that
you maintain your insurance coverage, if nothing else.

I think GAMI generated enough data on their stand to run a computer dry.

http://www.engineteststand.com/

On Thu, 24 Jun 2004 09:14:59 -0700, Tom Sixkiller wrote:


"C J Campbell" wrote in message
...
I think Deakin is worth reading, but some of what he says should be taken
with a grain of salt. His columns are mostly based on experiments with his
own highly modified Bonanza, a few high performance radial engines, and
some
theory. In fact, a careful reading of his columns will show no test data
for
the most common engine and propeller combinations in use today.

You've not read hiscolumns about the test beds they've run at GAMI?


The reasons
for this are fairly simple -- few airplanes have the instrumentation that
Deakin needs to test his theories. This is why Deakin's theories for
running
lean of peak remain a minority view. Granted, it is a very noisy minority,
but remember that it is also a small minority. I think they have a point.
They may even be right. But they don't have nearly the evidence that they
think they have.

See above.

Deakin's remarks are mostly pertinent to running TCM engines, which are
much
different than engines from other manufacturers.

I bellieve they run Lycoming on the test bed as well, everything from
pipsqueaks to the big 540's.

Not to put too fine a point
on it, some TCM engines are the only ones I know of that so consistently
develop cracks that the most part of an annual inspection basically
consists
of measuring and cataloging the spread of these cracks. The engine used in
the early 70's Cessna T206 rarely made it to its 1400 hour TBO, for
example.

Barring solid data to the contrary (and Deakin, remember, does not give
you
solid data -- he only appears to do that), your airplane should be
operated
in accordance with the manufacturer's recommendations. This will ensure
that
you maintain your insurance coverage, if nothing else.

I think GAMI generated enough data on their stand to run a computer dry.

http://www.engineteststand.com/

Is the data offered in the articles you refer to or is it available on
the web site? It does not appear to be jumping out at me. I see a couple
of pictures of some graphs, a webring link, and email address, and a link
to gami.com. What am I missing?

Thanks,

Greg

"Tom Sixkiller" wrote in message
...

"C J Campbell" wrote in message
...
I think Deakin is worth reading, but some of what he says should be
taken
with a grain of salt. His columns are mostly based on experiments with
his
own highly modified Bonanza, a few high performance radial engines, and
some
theory. In fact, a careful reading of his columns will show no test data
for
the most common engine and propeller combinations in use today.

You've not read hiscolumns about the test beds they've run at GAMI?

I merely point out that his theories are controversial -- they are hardly
universally accepted, as even this thread amply demonstrates. As I said, I
think he has a point, but I have to consider that the engine manufacturers
and aircraft manufacturers might know at least as much about their products
as GAMI does.

"C J Campbell" wrote in message
...

"Tom Sixkiller" wrote in message
...

"C J Campbell" wrote in message
...
I think Deakin is worth reading, but some of what he says should be
taken
with a grain of salt. His columns are mostly based on experiments with
his
own highly modified Bonanza, a few high performance radial engines,
and
some
theory. In fact, a careful reading of his columns will show no test
data
for
the most common engine and propeller combinations in use today.

You've not read hiscolumns about the test beds they've run at GAMI?

I merely point out that his theories are controversial -- they are hardly
universally accepted, as even this thread amply demonstrates.

Ah...no, you said he doesn't support his conclusions. Charles "Cory" Scott
actually did a very elaborate reply that explains it better than I have the
patience for.

As I said, I
think he has a point, but I have to consider that the engine manufacturers
and aircraft manufacturers might know at least as much about their
products
as GAMI does.

You might want to look into that, because the test stand data shows they may
not know as much as they pretend. Sounds more to me like the manufacturers
are trying to cover their asses for poor quality and potential legal
liability.

Have you looked at the data that Cory and I pointed you to?

"C J Campbell" wrote
I merely point out that his theories are controversial -- they are hardly
universally accepted, as even this thread amply demonstrates.

A thread on usenet demonstrates no such thing. Evolution is hardly
controversial within the scientific community, yet it is debated ad
nauseam on usenet. Deakin's theories (which are really not his at
all, and not really theories) are really no more controversial - in
fact, they formed the basis of normal operating practice for piston
fighter and airliners for as long as there were piston fighters and
airliners.

As I said, I
think he has a point, but I have to consider that the engine manufacturers
and aircraft manufacturers might know at least as much about their products
as GAMI does.

That was true once, but is true no longer. For all practical
purposes, there hasn't been any progress made in piston aircraft
engines for decades. Neither Lycoming nor Continental have a design
engineering staff anymore. Most of the knowledge has been lost.

It's actually fairly common for knowledge to be lost that way. Doing
development is fun; documenting it isn't. When the people who did the
development move on, a lot is lost. Corporate-mandated processes
generally don't help much - they just cause the brightest people to
move on sooner.

Michael

Howdy!

In article ,
C J Campbell wrote:

"Tom Sixkiller" wrote in message
...

"C J Campbell" wrote in message
...
I think Deakin is worth reading, but some of what he says should be
taken
with a grain of salt. His columns are mostly based on experiments with
his
own highly modified Bonanza, a few high performance radial engines, and
some
theory. In fact, a careful reading of his columns will show no test data
for
the most common engine and propeller combinations in use today.

You've not read hiscolumns about the test beds they've run at GAMI?

I merely point out that his theories are controversial -- they are hardly
universally accepted, as even this thread amply demonstrates. As I said, I
think he has a point, but I have to consider that the engine manufacturers
and aircraft manufacturers might know at least as much about their products
as GAMI does.

No. You do not "merely" point out... You do it in a manner that, intentional
or no, suggests that he is blowing smoke up your backside. You further
appear to completely disregard the supporting data and arguments, both from
GAMI testbeds and from historical operating practices for piston engined
aircraft. He does offer credible arguments that the engine manufacturers
offer recommendations contrary to good engineering and operating practices.

Let's be honest here.

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/

"Michael Houghton" wrote in message
...

No. You do not "merely" point out... You do it in a manner that,
intentional
or no, suggests that he is blowing smoke up your backside. You further
appear to completely disregard the supporting data and arguments, both
from
GAMI testbeds and from historical operating practices for piston engined
aircraft. He does offer credible arguments that the engine manufacturers
offer recommendations contrary to good engineering and operating
practices.

Let's be honest here.

All right, let's be honest. I am not disregarding the data that he as
presented in his articles. I will also not disregard the anecdotal evidence
that I have from several engine shops that engines consistently run LOP
generally do not make TBO, nor do they last as long as engines run according
to manufacturers' specifications. When Deakin comes up with hard evidence
that applies to anything other than GAMI's special setups then I will
welcome it. If there is anything that drives me up the wall, it is these
vague references to "historical operating practices." It is really just a
substitute for "bull****."