Prop pitch cycling?

[Frode Berg]

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

[Dudley Henriques]

"Frode Berg" > wrote in message
...
> 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

POH rules of course, but aside from that, I always liked to exercise a prop
through several cycles, especially when cold, just to get everything nice
and warm and fluid up there.
Dudley Henriques

[Jim Macklin]

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]. If the prop control is
not rigged properly the prop will feather too soon. Then
the prop feather check should be done.

Most props have a certain amount of internal leakage to keep
warm oil circulating in the prop hub, but several cycles on
a cold engine/prop will assure that the prop does reach
proper operating temperatures.

In very cold temperatures, I like to vary the rpm every some
often to be sure the prop is functioning, but normal
internal flow should make this mostly an unneeded habit.

Remember, on a single-engine reducing rpm send oil to the
prop and on a multi, reducing rpm/feathering drain oil from
the prop.


--
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
ink.net...
|
| "Frode Berg" > wrote in message
| ...
| > 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
|
| POH rules of course, but aside from that, I always liked
to exercise a prop
| through several cycles, especially when cold, just to get
everything nice
| and warm and fluid up there.
| Dudley Henriques
|
|

[Dudley Henriques]

If all this was meant for me, I'm pretty sure I just might already know
these things
:-)
Dudley Henriques

"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]. If the prop control is
> not rigged properly the prop will feather too soon. Then
> the prop feather check should be done.
>
> Most props have a certain amount of internal leakage to keep
> warm oil circulating in the prop hub, but several cycles on
> a cold engine/prop will assure that the prop does reach
> proper operating temperatures.
>
> In very cold temperatures, I like to vary the rpm every some
> often to be sure the prop is functioning, but normal
> internal flow should make this mostly an unneeded habit.
>
> Remember, on a single-engine reducing rpm send oil to the
> prop and on a multi, reducing rpm/feathering drain oil from
> the prop.
>
>
> --
> 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
> ink.net...
> |
> | "Frode Berg" > wrote in message
> | ...
> | > 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
> |
> | POH rules of course, but aside from that, I always liked
> to exercise a prop
> | through several cycles, especially when cold, just to get
> everything nice
> | and warm and fluid up there.
> | Dudley Henriques
> |
> |
>
>

[Jim Macklin]

No, I know that, I just tacked it on the thread for the
benefit of the others. I think most pilots and many
mechanics don't really understand these things, judging by
the number of twins that feather before the prop lever gets
to the gate.

If I win the lottery, odds 146 million to one, we can have
that CFI round table and sell tickets to anyone without a
CFI. CFIs can come for free. I'll pay for you and me. If I
don't win the lottery, it will have to be in Wichita, can't
afford to go elsewhere without the lottery. ;-)'

--
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...
| If all this was meant for me, I'm pretty sure I just
might already know
| these things
| :-)
| Dudley Henriques
|
| "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]. If the prop control
is
| > not rigged properly the prop will feather too soon.
Then
| > the prop feather check should be done.
| >
| > Most props have a certain amount of internal leakage to
keep
| > warm oil circulating in the prop hub, but several cycles
on
| > a cold engine/prop will assure that the prop does reach
| > proper operating temperatures.
| >
| > In very cold temperatures, I like to vary the rpm every
some
| > often to be sure the prop is functioning, but normal
| > internal flow should make this mostly an unneeded habit.
| >
| > Remember, on a single-engine reducing rpm send oil to
the
| > prop and on a multi, reducing rpm/feathering drain oil
from
| > the prop.
| >
| >
| > --
| > 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
| >
ink.net...
| > |
| > | "Frode Berg" > wrote in message
| > | ...
| > | > 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
| > |
| > | POH rules of course, but aside from that, I always
liked
| > to exercise a prop
| > | through several cycles, especially when cold, just to
get
| > everything nice
| > | and warm and fluid up there.
| > | Dudley Henriques
| > |
| > |
| >
| >
|
|

[Dudley Henriques]

I've done this a few times myself. :-)
On Usenet, if you underpost someone already in the thread but NOT the
original poster, what you post is considered addressed to the person you
underposted rather than simply an addition to the general thread.
Any general comment should be picked up as a post to the original poster by
clicking his/her post for reply. Then the comment appears referenced to the
initial question and not the sub poster.
I did the same thing once and gave a hundred word "lecture" on how to do a
slow roll to one of the world's best acro pilots by accidentally picking him
up to underpost instead of the initial poster who had asked about rolls. :-)
The pilot I gave the lecture to simply gave me a one word reply "Thanks"
with a smilie attached :-)
That get together sounds like fun. I'll bring the bottle!
Dudley



"Jim Macklin" > wrote in message
news:nZT2g.6827$ZW3.3603@dukeread04...
> No, I know that, I just tacked it on the thread for the
> benefit of the others. I think most pilots and many
> mechanics don't really understand these things, judging by
> the number of twins that feather before the prop lever gets
> to the gate.
>
> If I win the lottery, odds 146 million to one, we can have
> that CFI round table and sell tickets to anyone without a
> CFI. CFIs can come for free. I'll pay for you and me. If I
> don't win the lottery, it will have to be in Wichita, can't
> afford to go elsewhere without the lottery. ;-)'
>
> --
> James H. Macklin
> ATP,CFI,A&P
>
> --
> The people think the Constitution protects their rights;
> But government sees it as an obstacle to be overcome.
> some support
> http://www.usdoj.gov/olc/secondamendment2.htm
> See http://www.fija.org/ more about your rights and duties.
>
>
> "Dudley Henriques" > wrote in
> message
> nk.net...
> | If all this was meant for me, I'm pretty sure I just
> might already know
> | these things
> | :-)
> | Dudley Henriques
> |
> | "Jim Macklin" > wrote
> in message
> | news:yZS2g.6789$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]. If the prop control
> is
> | > not rigged properly the prop will feather too soon.
> Then
> | > the prop feather check should be done.
> | >
> | > Most props have a certain amount of internal leakage to
> keep
> | > warm oil circulating in the prop hub, but several cycles
> on
> | > a cold engine/prop will assure that the prop does reach
> | > proper operating temperatures.
> | >
> | > In very cold temperatures, I like to vary the rpm every
> some
> | > often to be sure the prop is functioning, but normal
> | > internal flow should make this mostly an unneeded habit.
> | >
> | > Remember, on a single-engine reducing rpm send oil to
> the
> | > prop and on a multi, reducing rpm/feathering drain oil
> from
> | > the prop.
> | >
> | >
> | > --
> | > 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
> | >
> ink.net...
> | > |
> | > | "Frode Berg" > wrote in message
> | > | ...
> | > | > 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
> | > |
> | > | POH rules of course, but aside from that, I always
> liked
> | > to exercise a prop
> | > | through several cycles, especially when cold, just to
> get
> | > everything nice
> | > | and warm and fluid up there.
> | > | Dudley Henriques
> | > |
> | > |
> | >
> | >
> |
> |
>
>

[Peter R.]

Jim Macklin > wrote:

> No, I know that, I just tacked it on the thread for the
> benefit of the others. I think most pilots and many
> mechanics don't really understand these things, judging by
> the number of twins that feather before the prop lever gets
> to the gate.

Thanks, Jim, for the added information. That's how I read your post; not
a correction to Dudley's, but rather an addendum for us less knowledgeable.

--
Peter

[Scott Skylane]

Jim Macklin wrote:

snip/
> Remember, on a single-engine, reducing rpm sends oil to the
> prop and on a multi, reducing rpm/feathering drains oil from
> the prop.
>
>

Well, generally this is true, but not always. Hamilton Standard
Hydro-Matic props, as used on the big radials, pump high pressure oil
*into* the hub for feathering. If you have complete oil loss, or let
the oil get too hot (and thin), you're out of luck for feathering.

Happy Flying!
Scott Skylane

[Jim Macklin]

Just to add to the total thread, for the uninitiated, a
constant speed prop isn't really constant, the blade angle
is hunting back and forth to adjust for varied aerodynamic
loads. So, once the plane is warm and in operation, oil in
the prop dome generally stays plenty warm. But if you are
flying a multiengine aircraft in cold weather and shut an
engine down in training including feathering, the oil may
congeal to the point the prop won't unfeather. So ME CFI be
careful what and where you practice.

I look forward to winning the lottery and buying you a
drink.

Jim
"Dudley Henriques" > wrote in
message
link.net...
| I've done this a few times myself. :-)
| On Usenet, if you underpost someone already in the thread
but NOT the
| original poster, what you post is considered addressed to
the person you
| underposted rather than simply an addition to the general
thread.
| Any general comment should be picked up as a post to the
original poster by
| clicking his/her post for reply. Then the comment appears
referenced to the
| initial question and not the sub poster.
| I did the same thing once and gave a hundred word
"lecture" on how to do a
| slow roll to one of the world's best acro pilots by
accidentally picking him
| up to underpost instead of the initial poster who had
asked about rolls. :-)
| The pilot I gave the lecture to simply gave me a one word
reply "Thanks"
| with a smilie attached :-)
| That get together sounds like fun. I'll bring the bottle!
| Dudley
|
|
|
| "Jim Macklin" > wrote
in message
| news:nZT2g.6827$ZW3.3603@dukeread04...
| > No, I know that, I just tacked it on the thread for the
| > benefit of the others. I think most pilots and many
| > mechanics don't really understand these things, judging
by
| > the number of twins that feather before the prop lever
gets
| > to the gate.
| >
| > If I win the lottery, odds 146 million to one, we can
have
| > that CFI round table and sell tickets to anyone without
a
| > CFI. CFIs can come for free. I'll pay for you and me.
If I
| > don't win the lottery, it will have to be in Wichita,
can't
| > afford to go elsewhere without the lottery. ;-)'
| >
| > --
| > James H. Macklin
| > ATP,CFI,A&P
| >
| > --
| > The people think the Constitution protects their rights;
| > But government sees it as an obstacle to be overcome.
| > some support
| > http://www.usdoj.gov/olc/secondamendment2.htm
| > See http://www.fija.org/ more about your rights and
duties.
| >
| >
| > "Dudley Henriques" > wrote in
| > message
| >
nk.net...
| > | If all this was meant for me, I'm pretty sure I just
| > might already know
| > | these things
| > | :-)
| > | Dudley Henriques
| > |
| > | "Jim Macklin" >
wrote
| > in message
| > | news:yZS2g.6789$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]. If the prop
control
| > is
| > | > not rigged properly the prop will feather too soon.
| > Then
| > | > the prop feather check should be done.
| > | >
| > | > Most props have a certain amount of internal leakage
to
| > keep
| > | > warm oil circulating in the prop hub, but several
cycles
| > on
| > | > a cold engine/prop will assure that the prop does
reach
| > | > proper operating temperatures.
| > | >
| > | > In very cold temperatures, I like to vary the rpm
every
| > some
| > | > often to be sure the prop is functioning, but normal
| > | > internal flow should make this mostly an unneeded
habit.
| > | >
| > | > Remember, on a single-engine reducing rpm send oil
to
| > the
| > | > prop and on a multi, reducing rpm/feathering drain
oil
| > from
| > | > the prop.
| > | >
| > | >
| > | > --
| > | > 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
| > | >
| >
ink.net...
| > | > |
| > | > | "Frode Berg" > wrote in
message
| > | > | ...
| > | > | > 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
| > | > |
| > | > | POH rules of course, but aside from that, I always
| > liked
| > | > to exercise a prop
| > | > | through several cycles, especially when cold, just
to
| > get
| > | > everything nice
| > | > | and warm and fluid up there.
| > | > | Dudley Henriques
| > | > |
| > | > |
| > | >
| > | >
| > |
| > |
| >
| >
|
|

[Jim Macklin]

That's is true, but except for the Beech 18, are there any
HS props on an airplane under 12,500 pounds?

The feathering on the HS is a electrical relay that turns on
a high pressure pump that operates at a pressure above
governor pressure. The Prop is feathered and the pump shuts
off. To unfeather the button is held in so the pump
continues to run and that causes the internal valve to move,
re-routing the oil so it unfeathers.

I wonder many pilots will take this to heart and open their
POH to the systems section?


--
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.


"Scott Skylane" > wrote in message
...
| Jim Macklin wrote:
|
| snip/
| > Remember, on a single-engine, reducing rpm sends oil to
the
| > prop and on a multi, reducing rpm/feathering drains oil
from
| > the prop.
| >
| >
|
| Well, generally this is true, but not always. Hamilton
Standard
| Hydro-Matic props, as used on the big radials, pump high
pressure oil
| *into* the hub for feathering. If you have complete oil
loss, or let
| the oil get too hot (and thin), you're out of luck for
feathering.
|
| Happy Flying!
| Scott Skylane
|

[Dudley Henriques]

"Jim Macklin" > wrote in message
news:nqW2g.7077$ZW3.4090@dukeread04...
> That's is true, but except for the Beech 18, are there any
> HS props on an airplane under 12,500 pounds?
>
> The feathering on the HS is a electrical relay that turns on
> a high pressure pump that operates at a pressure above
> governor pressure. The Prop is feathered and the pump shuts
> off. To unfeather the button is held in so the pump
> continues to run and that causes the internal valve to move,
> re-routing the oil so it unfeathers.
>
> I wonder many pilots will take this to heart and open their
> POH to the systems section?
>
>
> --
> James H. Macklin
> ATP,CFI,A&P

Oh for the simple life of fighters!! :-) I used Hamilton Standard props
quite a lot, but few of them feathered.
The 24D50 on my Mustang didn't feather of course :-) If I remember right,
the pitch range on my prop was something like 42 degrees.
Dudley

[Dudley Henriques]

"Jim Macklin" > wrote in message
news:lqW2g.7075$ZW3.2577@dukeread04...
> I look forward to winning the lottery and buying you a
> drink.
>
> Jim

Hell, unless one of us has to put gas in our cars, we should be able to
afford a bottle of Jack Daniels between us :-)))
Dudley



> "Dudley Henriques" > wrote in
> message
> link.net...
> | I've done this a few times myself. :-)
> | On Usenet, if you underpost someone already in the thread
> but NOT the
> | original poster, what you post is considered addressed to
> the person you
> | underposted rather than simply an addition to the general
> thread.
> | Any general comment should be picked up as a post to the
> original poster by
> | clicking his/her post for reply. Then the comment appears
> referenced to the
> | initial question and not the sub poster.
> | I did the same thing once and gave a hundred word
> "lecture" on how to do a
> | slow roll to one of the world's best acro pilots by
> accidentally picking him
> | up to underpost instead of the initial poster who had
> asked about rolls. :-)
> | The pilot I gave the lecture to simply gave me a one word
> reply "Thanks"
> | with a smilie attached :-)
> | That get together sounds like fun. I'll bring the bottle!
> | Dudley
> |
> |
> |
> | "Jim Macklin" > wrote
> in message
> | news:nZT2g.6827$ZW3.3603@dukeread04...
> | > No, I know that, I just tacked it on the thread for the
> | > benefit of the others. I think most pilots and many
> | > mechanics don't really understand these things, judging
> by
> | > the number of twins that feather before the prop lever
> gets
> | > to the gate.
> | >
> | > If I win the lottery, odds 146 million to one, we can
> have
> | > that CFI round table and sell tickets to anyone without
> a
> | > CFI. CFIs can come for free. I'll pay for you and me.
> If I
> | > don't win the lottery, it will have to be in Wichita,
> can't
> | > afford to go elsewhere without the lottery. ;-)'
> | >
> | > --
> | > James H. Macklin
> | > ATP,CFI,A&P
> | >
> | > --
> | > The people think the Constitution protects their rights;
> | > But government sees it as an obstacle to be overcome.
> | > some support
> | > http://www.usdoj.gov/olc/secondamendment2.htm
> | > See http://www.fija.org/ more about your rights and
> duties.
> | >
> | >
> | > "Dudley Henriques" > wrote in
> | > message
> | >
> nk.net...
> | > | If all this was meant for me, I'm pretty sure I just
> | > might already know
> | > | these things
> | > | :-)
> | > | Dudley Henriques
> | > |
> | > | "Jim Macklin" >
> wrote
> | > in message
> | > | news:yZS2g.6789$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]. If the prop
> control
> | > is
> | > | > not rigged properly the prop will feather too soon.
> | > Then
> | > | > the prop feather check should be done.
> | > | >
> | > | > Most props have a certain amount of internal leakage
> to
> | > keep
> | > | > warm oil circulating in the prop hub, but several
> cycles
> | > on
> | > | > a cold engine/prop will assure that the prop does
> reach
> | > | > proper operating temperatures.
> | > | >
> | > | > In very cold temperatures, I like to vary the rpm
> every
> | > some
> | > | > often to be sure the prop is functioning, but normal
> | > | > internal flow should make this mostly an unneeded
> habit.
> | > | >
> | > | > Remember, on a single-engine reducing rpm send oil
> to
> | > the
> | > | > prop and on a multi, reducing rpm/feathering drain
> oil
> | > from
> | > | > the prop.
> | > | >
> | > | >
> | > | > --
> | > | > 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
> | > | >
> | >
> ink.net...
> | > | > |
> | > | > | "Frode Berg" > wrote in
> message
> | > | > | ...
> | > | > | > 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
> | > | > |
> | > | > | POH rules of course, but aside from that, I always
> | > liked
> | > | > to exercise a prop
> | > | > | through several cycles, especially when cold, just
> to
> | > get
> | > | > everything nice
> | > | > | and warm and fluid up there.
> | > | > | Dudley Henriques
> | > | > |
> | > | > |
> | > | >
> | > | >
> | > |
> | > |
> | >
> | >
> |
> |
>
>

[[email protected]]

On Sun, 23 Apr 2006 21:06:12 -0500, "Jim Macklin"
> wrote:

>That's is true, but except for the Beech 18, are there any
>HS props on an airplane under 12,500 pounds?
>
>The feathering on the HS is a electrical relay that turns on
>a high pressure pump that operates at a pressure above
>governor pressure. The Prop is feathered and the pump shuts
>off. To unfeather the button is held in so the pump
>continues to run and that causes the internal valve to move,
>re-routing the oil so it unfeathers.

Heh. I typically "cycled" a freshly o-hauled HS to feather and back
static, then started the engine and function-checked it after
installation.

Got really busy one afternoon/evening, cycled the prop, but didn't get
the test run in. Aircraft in question got dispatched on a last minute
run-and I got a phone call @ 3:00 am.

Line guy hopped up on the wing and topped off the oil tank (to
replace what I had pumped into the engine). When the plane arrived at
its destination, the pilot attempted to check the oil-took the cap
off, oil started running out, cap back on, called home and asked for
help.

Was also a really pretty fan-shaped spray pattern of oil on the ramp
where the run-up was done prior to the first departure.

>I wonder many pilots will take this to heart and open their
>POH to the systems section?

In this forum, probably quite a few.

TC

[Jim Macklin]

Sounds good. Right now I'm trying some cheap brandy, but
Jack is awfully good. I don't drink much, maybe one once a
week now. But I'm going to have one tonight, a toast to all
the WWII pilots, to Scott Crossfield, to Dale Earnhardt and
to Tiger Woods dad. And all the troops in harm's way.


--
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...
|
| "Jim Macklin" > wrote
in message
| news:lqW2g.7075$ZW3.2577@dukeread04...
| > I look forward to winning the lottery and buying you a
| > drink.
| >
| > Jim
|
| Hell, unless one of us has to put gas in our cars, we
should be able to
| afford a bottle of Jack Daniels between us :-)))
| Dudley
|
|
|
| > "Dudley Henriques" > wrote in
| > message
| >
link.net...
| > | I've done this a few times myself. :-)
| > | On Usenet, if you underpost someone already in the
thread
| > but NOT the
| > | original poster, what you post is considered addressed
to
| > the person you
| > | underposted rather than simply an addition to the
general
| > thread.
| > | Any general comment should be picked up as a post to
the
| > original poster by
| > | clicking his/her post for reply. Then the comment
appears
| > referenced to the
| > | initial question and not the sub poster.
| > | I did the same thing once and gave a hundred word
| > "lecture" on how to do a
| > | slow roll to one of the world's best acro pilots by
| > accidentally picking him
| > | up to underpost instead of the initial poster who had
| > asked about rolls. :-)
| > | The pilot I gave the lecture to simply gave me a one
word
| > reply "Thanks"
| > | with a smilie attached :-)
| > | That get together sounds like fun. I'll bring the
bottle!
| > | Dudley
| > |
| > |
| > |
| > | "Jim Macklin" >
wrote
| > in message
| > | news:nZT2g.6827$ZW3.3603@dukeread04...
| > | > No, I know that, I just tacked it on the thread for
the
| > | > benefit of the others. I think most pilots and many
| > | > mechanics don't really understand these things,
judging
| > by
| > | > the number of twins that feather before the prop
lever
| > gets
| > | > to the gate.
| > | >
| > | > If I win the lottery, odds 146 million to one, we
can
| > have
| > | > that CFI round table and sell tickets to anyone
without
| > a
| > | > CFI. CFIs can come for free. I'll pay for you and
me.
| > If I
| > | > don't win the lottery, it will have to be in
Wichita,
| > can't
| > | > afford to go elsewhere without the lottery. ;-)'
| > | >
| > | > --
| > | > 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...
| > | > | If all this was meant for me, I'm pretty sure I
just
| > | > might already know
| > | > | these things
| > | > | :-)
| > | > | Dudley Henriques
| > | > |
| > | > | "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]. If the prop
| > control
| > | > is
| > | > | > not rigged properly the prop will feather too
soon.
| > | > Then
| > | > | > the prop feather check should be done.
| > | > | >
| > | > | > Most props have a certain amount of internal
leakage
| > to
| > | > keep
| > | > | > warm oil circulating in the prop hub, but
several
| > cycles
| > | > on
| > | > | > a cold engine/prop will assure that the prop
does
| > reach
| > | > | > proper operating temperatures.
| > | > | >
| > | > | > In very cold temperatures, I like to vary the
rpm
| > every
| > | > some
| > | > | > often to be sure the prop is functioning, but
normal
| > | > | > internal flow should make this mostly an
unneeded
| > habit.
| > | > | >
| > | > | > Remember, on a single-engine reducing rpm send
oil
| > to
| > | > the
| > | > | > prop and on a multi, reducing rpm/feathering
drain
| > oil
| > | > from
| > | > | > the prop.
| > | > | >
| > | > | >
| > | > | > --
| > | > | > 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
| > | > | >
| > | >
| >
ink.net...
| > | > | > |
| > | > | > | "Frode Berg" > wrote in
| > message
| > | > | > | ...
| > | > | > | > 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
| > | > | > |
| > | > | > | POH rules of course, but aside from that, I
always
| > | > liked
| > | > | > to exercise a prop
| > | > | > | through several cycles, especially when cold,
just
| > to
| > | > get
| > | > | > everything nice
| > | > | > | and warm and fluid up there.
| > | > | > | Dudley Henriques
| > | > | > |
| > | > | > |
| > | > | >
| > | > | >
| > | > |
| > | > |
| > | >
| > | >
| > |
| > |
| >
| >
|
|

[Bob Moore]

Jim Macklin wrote

> But if you are
> flying a multiengine aircraft in cold weather and shut an
> engine down in training including feathering, the oil may
> congeal to the point the prop won't unfeather. So ME CFI be
> careful what and where you practice.

That is true of course unless you happen to be flying a big
turboprop that uses something similiar to hydraulic oil for
its prop control mechanism. We routinely shutdown (feathered)
numbers 1 and 4 for endurance purposes.

Bob Moore Allison T-56 operator

[Jim Macklin]

Skydrol and similar are great. Turbine oil is also mostly
synthetic and doesn't congeal. But most people don't fly C
130s and hang out here, in rec.piloting.

Most ME training is done in a piston powered light twin with
petroleum based engine oil shared by the prop.


--
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.


"Bob Moore" > wrote in message
. 121...
| Jim Macklin wrote
|
| > But if you are
| > flying a multiengine aircraft in cold weather and shut
an
| > engine down in training including feathering, the oil
may
| > congeal to the point the prop won't unfeather. So ME
CFI be
| > careful what and where you practice.
|
| That is true of course unless you happen to be flying a
big
| turboprop that uses something similiar to hydraulic oil
for
| its prop control mechanism. We routinely shutdown
(feathered)
| numbers 1 and 4 for endurance purposes.
|
| Bob Moore Allison T-56 operator

[Al]

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

[Ronald Gardner]

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

[Jim Macklin]

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.



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

"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
|
|
|
|
|

[Dudley Henriques]

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]

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
| >
| >
| >
| >
| >
|
|

[Dudley Henriques]

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]

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
| > | >
| > | >
| > | >
| > | >
| > | >
| > |
| > |
| >
| >
|
|

[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

[Jim Macklin]

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
|
|
|

[karl gruber]

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
>
>
>

[Jim Macklin]

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
| >
| >
| >
|
|

[Michael Ware]

"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.

[Al]

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
>>
>>
>>
>
>

[Frode Berg]

"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