Prop pitch cycling?

Nice link. Good article.


--
James H. Macklin
ATP,CFI,A&P

"Dudley Henriques" wrote in
message
nk.net...
| Hi Al;
|
| May I refer you to an article written by John Deakin. John
has written an
| excellent explanation for exactly what you are asking
about here.
|
| http://www.avweb.com/news/columns/182082-1.html
|
| All the best,
| Dudley
|
| "Al" wrote in message
| ...
| Jim & Dudley, I've a question I've been meaning to ask.
|
|
| "Jim Macklin"
wrote in message
| news:yZS2g.6789$ZW3.6526@dukeread04...
| The prop governor controls within a range and should
hold a
| steady rpm within that range. When the run-up is done
at
| say, 2400 rpm the prop should be cycled to the minimum
rpm
| and allowed to stabilize for a few seconds to check
that the
| governor is working properly. On a multiengine
airplane the
| prop should be reduced to just outside the feather
detent
| and allowed to run for several seconds to be sure that
the
| prop isn't feathering at the minimum governed speed
[usually
| 2000 rpm on most piston engines].
|
| What is the minimum governed speed on a constant
speed prop?
|
| It has been my experience that below 1200-1400 rpm
someplace, a C/s
| prop will no longer cycle. In a glide, the RPM is
generally below that.
| In another thread, some time ago, you(Jim) mentioned
that to get the best
| glide out of a single engine(without the engine), one
should pull the prop
| control out fully. I have tried this in a Mooney 201,
and could not make
| the RPM change a bit, (Power off, best glide).
|
| Have any of you ever been able in influence a glide
with the prop
| control?
|
| Al
|
|
|
|
|
|
|

Deak has a ton of time in big radials and is LOA for several warbirds. His
stuff is off the cuff and straight forward.
I like his style.
Dudley

"Jim Macklin" wrote in message
news:u1g3g.8051$ZW3.6469@dukeread04...
Nice link. Good article.


--
James H. Macklin
ATP,CFI,A&P

"Dudley Henriques" wrote in
message
nk.net...
| Hi Al;
|
| May I refer you to an article written by John Deakin. John
has written an
| excellent explanation for exactly what you are asking
about here.
|
| http://www.avweb.com/news/columns/182082-1.html
|
| All the best,
| Dudley
|
| "Al" wrote in message
| ...
| Jim & Dudley, I've a question I've been meaning to ask.
|
|
| "Jim Macklin"
wrote in message
| news:yZS2g.6789$ZW3.6526@dukeread04...
| The prop governor controls within a range and should
hold a
| steady rpm within that range. When the run-up is done
at
| say, 2400 rpm the prop should be cycled to the minimum
rpm
| and allowed to stabilize for a few seconds to check
that the
| governor is working properly. On a multiengine
airplane the
| prop should be reduced to just outside the feather
detent
| and allowed to run for several seconds to be sure that
the
| prop isn't feathering at the minimum governed speed
[usually
| 2000 rpm on most piston engines].
|
| What is the minimum governed speed on a constant
speed prop?
|
| It has been my experience that below 1200-1400 rpm
someplace, a C/s
| prop will no longer cycle. In a glide, the RPM is
generally below that.
| In another thread, some time ago, you(Jim) mentioned
that to get the best
| glide out of a single engine(without the engine), one
should pull the prop
| control out fully. I have tried this in a Mooney 201,
and could not make
| the RPM change a bit, (Power off, best glide).
|
| Have any of you ever been able in influence a glide
with the prop
| control?
|
| Al
|
|
|
|
|
|
|

And now to sleep, to dream of charter flights in the King
Air or Beechjet, with wake-up calls that are late, blizzards
and floods, cold coffee, taxi strikes, no hotel car, my
clothes lost and I'm flying nude, I'm stuck on the outside
of the airplane, trying to get in the pilot's seat before
the crash as the plane flies between the buildings under the
telephone wires.

Good books are really nice, it even helps when they are easy
to read, unlike a lot of the factory manuals and government
publications.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Dudley Henriques" wrote in
message
nk.net...
| Deak has a ton of time in big radials and is LOA for
several warbirds. His
| stuff is off the cuff and straight forward.
| I like his style.
| Dudley
|
| "Jim Macklin" wrote
in message
| news:u1g3g.8051$ZW3.6469@dukeread04...
| Nice link. Good article.
|
|
| --
| James H. Macklin
| ATP,CFI,A&P
|
| "Dudley Henriques" wrote in
| message
|
nk.net...
| | Hi Al;
| |
| | May I refer you to an article written by John Deakin.
John
| has written an
| | excellent explanation for exactly what you are asking
| about here.
| |
| | http://www.avweb.com/news/columns/182082-1.html
| |
| | All the best,
| | Dudley
| |
| | "Al" wrote in message
| | ...
| | Jim & Dudley, I've a question I've been meaning to
ask.
| |
| |
| | "Jim Macklin"
| wrote in message
| | news:yZS2g.6789$ZW3.6526@dukeread04...
| | The prop governor controls within a range and
should
| hold a
| | steady rpm within that range. When the run-up is
done
| at
| | say, 2400 rpm the prop should be cycled to the
minimum
| rpm
| | and allowed to stabilize for a few seconds to check
| that the
| | governor is working properly. On a multiengine
| airplane the
| | prop should be reduced to just outside the feather
| detent
| | and allowed to run for several seconds to be sure
that
| the
| | prop isn't feathering at the minimum governed speed
| [usually
| | 2000 rpm on most piston engines].
| |
| | What is the minimum governed speed on a constant
| speed prop?
| |
| | It has been my experience that below 1200-1400
rpm
| someplace, a C/s
| | prop will no longer cycle. In a glide, the RPM is
| generally below that.
| | In another thread, some time ago, you(Jim) mentioned
| that to get the best
| | glide out of a single engine(without the engine),
one
| should pull the prop
| | control out fully. I have tried this in a Mooney
201,
| and could not make
| | the RPM change a bit, (Power off, best glide).
| |
| | Have any of you ever been able in influence a
glide
| with the prop
| | control?
| |
| | Al
| |
| |
| |
| |
| |
| |
| |
|
|
|
|

"Jim Macklin" wrote in message
news:l3d3g.8037$ZW3.808@dukeread04...
But did you notice a change in rate of descent when you
repositioned the prop? The rpm may not change but it should
change the blade angle and thus the drag.


No, I didn't.

If I had gotten the blade angle to change, the rpm would have changed also.

The windmilling prop is producing drag by generating lift which it uses to
turn the engine. It takes a certain amount of energy to turn the engine over
at 800 rpm or so. If, after pulling the prop control, the glide ratio
increases, then the prop is producing less drag, and has less energy with
which to turn the engine. This means the engine must slow down.

My original question was "What is the minimum governed speed on a constant
speed prop?"

I enjoyed the article Dudley pointed to, and the mechanics involved are
clear. But
there is a minimum rpm below which the centrifical weights do not respond,
and the oil is not sent to the prop to alter blade angle. A windmilling
engine at glide is below this rpm.

I believe that pulling the prop control in a glide in almost any of our
single engine aircraft, will have no effect on the glide. Indeed this is
indicated by it's lack of effect on the windmilling rpm.

Al CFIAMI

I have seen a change in Bonanzas and other models, it may be
different airplanes and engine/prop combinations will have
some different results.



"Al" wrote in message
...
|
| "Jim Macklin" wrote
in message
| news:l3d3g.8037$ZW3.808@dukeread04...
| But did you notice a change in rate of descent when you
| repositioned the prop? The rpm may not change but it
should
| change the blade angle and thus the drag.
|
|
| No, I didn't.
|
| If I had gotten the blade angle to change, the rpm would
have changed also.
|
| The windmilling prop is producing drag by generating lift
which it uses to
| turn the engine. It takes a certain amount of energy to
turn the engine over
| at 800 rpm or so. If, after pulling the prop control, the
glide ratio
| increases, then the prop is producing less drag, and has
less energy with
| which to turn the engine. This means the engine must slow
down.
|
| My original question was "What is the minimum governed
speed on a constant
| speed prop?"
|
| I enjoyed the article Dudley pointed to, and the mechanics
involved are
| clear. But
| there is a minimum rpm below which the centrifical weights
do not respond,
| and the oil is not sent to the prop to alter blade angle.
A windmilling
| engine at glide is below this rpm.
|
| I believe that pulling the prop control in a glide in
almost any of our
| single engine aircraft, will have no effect on the glide.
Indeed this is
| indicated by it's lack of effect on the windmilling rpm.
|
| Al CFIAMI
|
|
|

There is a big change in glide with respect to RPM. My 185 has a McCauley
"Big Foot" (86" 3 blade STC) prop which maximizes takeoff performance.
During a glide if I reposition the prop to max RPM the airplane will
noticeably decelerate, so much so that Bush pilots use this to their
advantage for steeper approaches.

Alternatively, pulling the prop noticeably extends the glide.

Karl
"Curator" N185KG


"Al" wrote in message
...

"Jim Macklin" wrote in message
news:l3d3g.8037$ZW3.808@dukeread04...
But did you notice a change in rate of descent when you
repositioned the prop? The rpm may not change but it should
change the blade angle and thus the drag.


No, I didn't.

If I had gotten the blade angle to change, the rpm would have changed
also.

The windmilling prop is producing drag by generating lift which it uses to
turn the engine. It takes a certain amount of energy to turn the engine
over at 800 rpm or so. If, after pulling the prop control, the glide ratio
increases, then the prop is producing less drag, and has less energy with
which to turn the engine. This means the engine must slow down.

My original question was "What is the minimum governed speed on a constant
speed prop?"

I enjoyed the article Dudley pointed to, and the mechanics involved are
clear. But
there is a minimum rpm below which the centrifical weights do not respond,
and the oil is not sent to the prop to alter blade angle. A windmilling
engine at glide is below this rpm.

I believe that pulling the prop control in a glide in almost any of our
single engine aircraft, will have no effect on the glide. Indeed this is
indicated by it's lack of effect on the windmilling rpm.

Al CFIAMI

That has been my experience. It may be that a low
compression engine or one with small displacement, or with
the throttle open or closed on a dead engine will make a
difference.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"karl gruber" wrote in message
...
| There is a big change in glide with respect to RPM. My 185
has a McCauley
| "Big Foot" (86" 3 blade STC) prop which maximizes takeoff
performance.
| During a glide if I reposition the prop to max RPM the
airplane will
| noticeably decelerate, so much so that Bush pilots use
this to their
| advantage for steeper approaches.
|
| Alternatively, pulling the prop noticeably extends the
glide.
|
| Karl
| "Curator" N185KG
|
|
| "Al" wrote in message
| ...
|
| "Jim Macklin"
wrote in message
| news:l3d3g.8037$ZW3.808@dukeread04...
| But did you notice a change in rate of descent when you
| repositioned the prop? The rpm may not change but it
should
| change the blade angle and thus the drag.
|
|
| No, I didn't.
|
| If I had gotten the blade angle to change, the rpm would
have changed
| also.
|
| The windmilling prop is producing drag by generating
lift which it uses to
| turn the engine. It takes a certain amount of energy to
turn the engine
| over at 800 rpm or so. If, after pulling the prop
control, the glide ratio
| increases, then the prop is producing less drag, and has
less energy with
| which to turn the engine. This means the engine must
slow down.
|
| My original question was "What is the minimum governed
speed on a constant
| speed prop?"
|
| I enjoyed the article Dudley pointed to, and the
mechanics involved are
| clear. But
| there is a minimum rpm below which the centrifical
weights do not respond,
| and the oil is not sent to the prop to alter blade
angle. A windmilling
| engine at glide is below this rpm.
|
| I believe that pulling the prop control in a glide in
almost any of our
| single engine aircraft, will have no effect on the
glide. Indeed this is
| indicated by it's lack of effect on the windmilling rpm.
|
| Al CFIAMI
|
|
|
|
|

"Ronald Gardner" wrote in message
...
On the C-182 I have always been told to cycle 3 time just enough for a 200
rpm
drop. This verifies it is working and the oil is flowing.

Ron

Frode Berg wrote:

Hi!

I was told by my mechanic to only pull the prop handle until I could
audibly
hear a slight pitch change to establish that it was working.

However, the aircraft manual says it should be cycled completely, and on
a
cold engine three times to make sure oil is applied to the governor, or
the
pitch mechanism.

Can someone elaborate on this?

What is recommended?

Thanks,

Frode

What the mechanic is telling you (I think), is to pull the pitch control all
the way out, but just for a moment, long enough for the RPM's to drop a
little. Don't pull it out and leave it.
On the first flight of the day, I always cycle it three times during the
runup. Like the manual says, it shows you that the governor is working and
allows warm oil to flow to it.

Do you get a change in the windmilling rpm also?

Al


"karl gruber" wrote in message
...
There is a big change in glide with respect to RPM. My 185 has a McCauley
"Big Foot" (86" 3 blade STC) prop which maximizes takeoff performance.
During a glide if I reposition the prop to max RPM the airplane will
noticeably decelerate, so much so that Bush pilots use this to their
advantage for steeper approaches.

Alternatively, pulling the prop noticeably extends the glide.

Karl
"Curator" N185KG


"Al" wrote in message
...

"Jim Macklin" wrote in message
news:l3d3g.8037$ZW3.808@dukeread04...
But did you notice a change in rate of descent when you
repositioned the prop? The rpm may not change but it should
change the blade angle and thus the drag.


No, I didn't.

If I had gotten the blade angle to change, the rpm would have changed
also.

The windmilling prop is producing drag by generating lift which it uses
to turn the engine. It takes a certain amount of energy to turn the
engine over at 800 rpm or so. If, after pulling the prop control, the
glide ratio increases, then the prop is producing less drag, and has less
energy with which to turn the engine. This means the engine must slow
down.

My original question was "What is the minimum governed speed on a
constant speed prop?"

I enjoyed the article Dudley pointed to, and the mechanics involved are
clear. But
there is a minimum rpm below which the centrifical weights do not
respond, and the oil is not sent to the prop to alter blade angle. A
windmilling engine at glide is below this rpm.

I believe that pulling the prop control in a glide in almost any of our
single engine aircraft, will have no effect on the glide. Indeed this is
indicated by it's lack of effect on the windmilling rpm.

Al CFIAMI

"Michael Ware"

What the mechanic is telling you (I think), is to pull the pitch control
all
the way out, but just for a moment, long enough for the RPM's to drop a
little. Don't pull it out and leave it.
On the first flight of the day, I always cycle it three times during the
runup. Like the manual says, it shows you that the governor is working and
allows warm oil to flow to it.



Do you mean pull the prop control all the way? Not just far enough to get a
200 rpm drop?
Pulling it all the way seams a bit harsh to me, and this is just what the
mechanic is saying, however, I've heard both....

Frode