Constant speed props

I'm taking delivery today of my first aircraft and it had a constant speed
prop. I have only flown fixed props thus far. I want to have as much
understanding of the c-s prop as possible before I get with my instructor. I
understand the basic difference in what the controls do, but I don't really
have a good understanding of the hows and whys of flying with them. Any
general information, explanations, and tips would be greatly appreciated.

In article , GE
wrote:

I'm taking delivery today of my first aircraft and it had a constant speed
prop. I have only flown fixed props thus far. I want to have as much
understanding of the c-s prop as possible before I get with my instructor. I
understand the basic difference in what the controls do, but I don't really
have a good understanding of the hows and whys of flying with them. Any
general information, explanations, and tips would be greatly appreciated.

Go to www.avweb.com
on the left side of the screen, select COLUMNS
scroll down to find THE PELICAN"S PERCH
there are articles on fuel injection, manifold pressure, constant speed
props, leaning, etc
Everything you ever want to know about operating a high performance
aircraft engine is in those articles.

Ge,

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

--
Thomas Borchert (EDDH)

"EDR" wrote in message
...
In article , GE
wrote:

I'm taking delivery today of my first aircraft and it had a constant
speed
prop. I have only flown fixed props thus far. I want to have as much
understanding of the c-s prop as possible before I get with my
instructor. I
understand the basic difference in what the controls do, but I don't
really
have a good understanding of the hows and whys of flying with them. Any
general information, explanations, and tips would be greatly
appreciated.

Go to www.avweb.com
on the left side of the screen, select COLUMNS
scroll down to find THE PELICAN"S PERCH
there are articles on fuel injection, manifold pressure, constant speed
props, leaning, etc
Everything you ever want to know about operating a high performance
aircraft engine is in those articles.

While I would agree that John Deakin is worth reading, people who are new to
high performance engines and constant speed propellers should be aware that
Deakin has many views that are highly controversial, to say the least,
especially when it comes to his religious crusade to get everyone to run
their engines lean of peak (which, of course, has spawned a full-scale
counter-reformation movement that tries to get everyone to run their engines
rich of peak).

EDR will eventually be converted to one side or the other and will run his
own airplane the way he sees fit, much to the disgust of those pilots that
will think he has gone over to the dark side.

If you are renting an airplane, though, run it the way the owner/operator
wants it treated, which is invariably in accordance with the manufacturer's
operating instructions.

On Thu, 24 Jun 2004 12:30:03 +0000, EDR wrote:

In article , GE
wrote:

I'm taking delivery today of my first aircraft and it had a constant speed
prop. I have only flown fixed props thus far. I want to have as much
understanding of the c-s prop as possible before I get with my instructor. I
understand the basic difference in what the controls do, but I don't really
have a good understanding of the hows and whys of flying with them. Any
general information, explanations, and tips would be greatly appreciated.

Go to www.avweb.com
on the left side of the screen, select COLUMNS
scroll down to find THE PELICAN"S PERCH
there are articles on fuel injection, manifold pressure, constant speed
props, leaning, etc
Everything you ever want to know about operating a high performance
aircraft engine is in those articles.


Great link!

I started reading this
article, http://www.avweb.com/news/columns/186619-1.html, and have a
question. In the Runup section, when he starts to test for proper mag
operation, somethings seems odd there. Can someone help explain that? He
says, "Are the mags working? The leaner the mixture, the more mag drop
you'll see on one mag, and that's normal." He then goes on to say, "The
EGTs should rise on the first single-mag operation, stay there for the
second, then drop again on the return to BOTH. That rise is proof-positive
the entire ignition system is working, and working well, and the leaner
the mixture, the more diagnostic it is."

Can someone help explain the supporting logic there? If both mags are
working properly and you switch to a single mag, why would the EGT go up?
After all, in theory, you're producing less spark and thusly, a slightly
less effecient ignition of the fuel/air. I would of thought that EGT
would stay the same or go down *just slightly* when running off of one
mag. Likewise, if one mag is not working, I would fully expect to see a
big EGT drop for the given problematic mag, which he does agree with.
But, he further asserts that, "If any of them fail to rise or even drop
during single-mag operation, there is a problem with that plug, the wire,
or the mag."

So, why would running on one mag, versus two, always cause higher EGTs?
And why would no rise in EGT indicate a bad mag, wire or plug?

Anyone?


P.S. I cross posted because this seems like good student pilot material
too.

On Thu, 24 Jun 2004 08:22:05 -0700, C J Campbell wrote:


"EDR" wrote in message
...
In article , GE
wrote:

I'm taking delivery today of my first aircraft and it had a constant
speed
prop. I have only flown fixed props thus far. I want to have as much
understanding of the c-s prop as possible before I get with my
instructor. I
understand the basic difference in what the controls do, but I don't
really
have a good understanding of the hows and whys of flying with them. Any
general information, explanations, and tips would be greatly
appreciated.

Go to www.avweb.com
on the left side of the screen, select COLUMNS
scroll down to find THE PELICAN"S PERCH
there are articles on fuel injection, manifold pressure, constant speed
props, leaning, etc
Everything you ever want to know about operating a high performance
aircraft engine is in those articles.

While I would agree that John Deakin is worth reading, people who are new to
high performance engines and constant speed propellers should be aware that
Deakin has many views that are highly controversial, to say the least,
especially when it comes to his religious crusade to get everyone to run
their engines lean of peak (which, of course, has spawned a full-scale
counter-reformation movement that tries to get everyone to run their engines
rich of peak).

EDR will eventually be converted to one side or the other and will run his
own airplane the way he sees fit, much to the disgust of those pilots that
will think he has gone over to the dark side.

If you are renting an airplane, though, run it the way the owner/operator
wants it treated, which is invariably in accordance with the manufacturer's
operating instructions.

Timely posting! That was going to be my next post. It bothered me how
lean he was suggesting the engine should be run. I guess that answers
that.

As usual, great advice!


Cheers!

"C J Campbell" wrote in message
...
While I would agree that John Deakin is worth reading, people who are new
to
high performance engines and constant speed propellers should be aware
that
Deakin has many views that are highly controversial, to say the least,

Does her or doesn't he provide copious data to support his position, and
doesn't he also provide copious data to show that it's the contrary postion
that's full of it?

especially when it comes to his religious crusade to get everyone to run
their engines lean of peak (which, of course, has spawned a full-scale
counter-reformation movement that tries to get everyone to run their
engines
rich of peak).

See above.

"Greg Copeland" wrote in message
news
On Thu, 24 Jun 2004 12:30:03 +0000, EDR wrote:

In article , GE
wrote:

I'm taking delivery today of my first aircraft and it had a constant
speed
prop. I have only flown fixed props thus far. I want to have as much
understanding of the c-s prop as possible before I get with my
instructor. I
understand the basic difference in what the controls do, but I don't
really
have a good understanding of the hows and whys of flying with them. Any
general information, explanations, and tips would be greatly
appreciated.

Go to www.avweb.com
on the left side of the screen, select COLUMNS
scroll down to find THE PELICAN"S PERCH
there are articles on fuel injection, manifold pressure, constant speed
props, leaning, etc
Everything you ever want to know about operating a high performance
aircraft engine is in those articles.


Great link!

I started reading this
article, http://www.avweb.com/news/columns/186619-1.html, and have a
question. In the Runup section, when he starts to test for proper mag
operation, somethings seems odd there. Can someone help explain that? He
says, "Are the mags working? The leaner the mixture, the more mag drop
you'll see on one mag, and that's normal." He then goes on to say, "The
EGTs should rise on the first single-mag operation, stay there for the
second, then drop again on the return to BOTH. That rise is proof-positive
the entire ignition system is working, and working well, and the leaner
the mixture, the more diagnostic it is."

Can someone help explain the supporting logic there? If both mags are
working properly and you switch to a single mag, why would the EGT go up?
After all, in theory, you're producing less spark and thusly, a slightly
less effecient ignition of the fuel/air. I would of thought that EGT
would stay the same or go down *just slightly* when running off of one
mag. Likewise, if one mag is not working, I would fully expect to see a
big EGT drop for the given problematic mag, which he does agree with.
But, he further asserts that, "If any of them fail to rise or even drop
during single-mag operation, there is a problem with that plug, the wire,
or the mag."

So, why would running on one mag, versus two, always cause higher EGTs?
And why would no rise in EGT indicate a bad mag, wire or plug?

Anyone?


P.S. I cross posted because this seems like good student pilot material
too.
The key is that with two plugs, the combustion _in the cylinder_ is more
complete, earlier. When one mag cuts, the fuel air mixture still fully
burns, but the burn is continued slightly latter (where it does less work on
the piston). This results in the gas coming out of the exhaust being a
little hotter (in some cases, it may even be still burning).

Best Wishes

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.

On Thu, 24 Jun 2004 16:41:32 +0100, Roger Hamlett wrote:


"Greg Copeland" wrote in message
news
On Thu, 24 Jun 2004 12:30:03 +0000, EDR wrote:

In article , GE
wrote:

I'm taking delivery today of my first aircraft and it had a constant
speed
prop. I have only flown fixed props thus far. I want to have as much
understanding of the c-s prop as possible before I get with my
instructor. I
understand the basic difference in what the controls do, but I don't
really
have a good understanding of the hows and whys of flying with them. Any
general information, explanations, and tips would be greatly
appreciated.

Go to www.avweb.com
on the left side of the screen, select COLUMNS
scroll down to find THE PELICAN"S PERCH
there are articles on fuel injection, manifold pressure, constant speed
props, leaning, etc
Everything you ever want to know about operating a high performance
aircraft engine is in those articles.


Great link!

I started reading this
article, http://www.avweb.com/news/columns/186619-1.html, and have a
question. In the Runup section, when he starts to test for proper mag
operation, somethings seems odd there. Can someone help explain that? He
says, "Are the mags working? The leaner the mixture, the more mag drop
you'll see on one mag, and that's normal." He then goes on to say, "The
EGTs should rise on the first single-mag operation, stay there for the
second, then drop again on the return to BOTH. That rise is proof-positive
the entire ignition system is working, and working well, and the leaner
the mixture, the more diagnostic it is."

Can someone help explain the supporting logic there? If both mags are
working properly and you switch to a single mag, why would the EGT go up?
After all, in theory, you're producing less spark and thusly, a slightly
less effecient ignition of the fuel/air. I would of thought that EGT
would stay the same or go down *just slightly* when running off of one
mag. Likewise, if one mag is not working, I would fully expect to see a
big EGT drop for the given problematic mag, which he does agree with.
But, he further asserts that, "If any of them fail to rise or even drop
during single-mag operation, there is a problem with that plug, the wire,
or the mag."

So, why would running on one mag, versus two, always cause higher EGTs?
And why would no rise in EGT indicate a bad mag, wire or plug?

Anyone?


P.S. I cross posted because this seems like good student pilot material
too.
The key is that with two plugs, the combustion _in the cylinder_ is more
complete, earlier. When one mag cuts, the fuel air mixture still fully
burns, but the burn is continued slightly latter (where it does less work on
the piston). This results in the gas coming out of the exhaust being a
little hotter (in some cases, it may even be still burning).

Best Wishes

Makes perfect sense! Thanks!