Emergency Procedures

In article ,
"Peter R." wrote:

Jim Macklin wrote:

Pulling the prop
control back moves the prop towards the high pitch stops.
Most pilots seem to think cycling the prop is just to
circulate fresh warm oil. Give the system a moment to have
the rpm stabilize to see what is happening.

Leave it there a moment? Hmmm, when I transitioned to the Bonanza, my
first constant speed prop aircraft, I was told by the very experienced CFI
not to let the RPMS drop too much during this pre-takeoff item or it would
place a high load on the engine (I believe his analogy was like shifting a
car into 4th gear while driving at 25 miles per hour).
Not true?

I cannot remember where I read it (sometime in the past year), not to
allow the rpm to drop more than 500 rpm during the prop check at runup
rpm.

In article
,
john smith wrote:

In article ,
"Peter R." wrote:

Jim Macklin wrote:

Pulling the prop
control back moves the prop towards the high pitch stops.
Most pilots seem to think cycling the prop is just to
circulate fresh warm oil. Give the system a moment to have
the rpm stabilize to see what is happening.

Leave it there a moment? Hmmm, when I transitioned to the Bonanza, my
first constant speed prop aircraft, I was told by the very experienced CFI
not to let the RPMS drop too much during this pre-takeoff item or it would
place a high load on the engine (I believe his analogy was like shifting a
car into 4th gear while driving at 25 miles per hour).
Not true?

I cannot remember where I read it (sometime in the past year), not to
allow the rpm to drop more than 500 rpm during the prop check at runup
rpm.

Go to http://www.mattituck.com/articles/goodhabt.htm and scroll down to
"Keep Propeller Cycling To A Minimum".

If there is limitation published for your airplane (POH),
certainly follow that, but the old wives' tale about
over-square operation is part of this issue. With enough
power applied, a CS prop will reach red-line rpm on the
ground [a fixed pitch won't, it has a published minimum rpm
with a particular prop]. You reach the rpm at less than
full throttle with a CS prop, which is on the low pitch
stop. Pull the rpm back causes the governor to send oil to
the hub which takes the prop off the low pitch stops. This
at about half throttle.
You can cruise at 120 kts {just a number} and minimum rpm at
say 2000 because air loads are reduced and you're using more
power. The rpm will decrease on a ground run because there
isn't enough power to keep the rpm up and you will get to
the high pitch stop.
In any case, you should be checking more than a connection
between the prop control and the prop, does the governor
govern? On a multiengine, will it run at the power rpm as
shown on the green arc and be stable? On a single-engine,
can you set some rpm below the initial run-up and does that
run at a constant speed.


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

--
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"john smith" wrote in message
...
| In article
,
| "Peter R." wrote:
|
| Jim Macklin
wrote:
|
| Pulling the prop
| control back moves the prop towards the high pitch
stops.
| Most pilots seem to think cycling the prop is just to
| circulate fresh warm oil. Give the system a moment to
have
| the rpm stabilize to see what is happening.
|
| Leave it there a moment? Hmmm, when I transitioned to
the Bonanza, my
| first constant speed prop aircraft, I was told by the
very experienced CFI
| not to let the RPMS drop too much during this
pre-takeoff item or it would
| place a high load on the engine (I believe his analogy
was like shifting a
| car into 4th gear while driving at 25 miles per hour).
| Not true?
|
| I cannot remember where I read it (sometime in the past
year), not to
| allow the rpm to drop more than 500 rpm during the prop
check at runup
| rpm.

"rod" wrote:

It, does work, but most people don't know it or teach it. The improvement
in glide isn't great, however.

It's over 50 FPM less sink in my airplane.

That may not seem like much, but if you only need a few more feet to glide
over some trees, it will seem like a whole lot.

--
Dan
C172RG at BFM

"john smith" wrote in message
...
In article TKdug.77158$ZW3.34119@dukeread04,
"Jim Macklin" wrote:

If the engine is turning, it has oil pressure.

Yes, but is there not a minimum RPM below which the governor has no
effect?

There is indeed. In my experience, cycling the prop on a windmilling engine
has no effect. I'm talking about a constant speed prop on a single engine
aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no
amount of pulling on the prop control would change that RPM. Obviously, if
the RPM doesn't change, the prop pitch didn't change, and the glide is not
affected.

Jim and I have 'round on this one before, but I stand by my observations.

Al G

Al wrote:

There is indeed. In my experience, cycling the prop on a windmilling engine
has no effect. I'm talking about a constant speed prop on a single engine
aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no
amount of pulling on the prop control would change that RPM. Obviously, if
the RPM doesn't change, the prop pitch didn't change, and the glide is not
affected.

Jim and I have 'round on this one before, but I stand by my observations.

Well, here's another data point on the same make and model, M20J. I don't have
the numbers to go with my observation, but subjectively when I pull the prop
control back at engine idle and ~best-glide, it feels like I just disengaged the
brakes.

On 7/17/2006 11:48 AM, Dave Butler wrote the following:
Al wrote:

There is indeed. In my experience, cycling the prop on a windmilling
engine has no effect. I'm talking about a constant speed prop on a
single engine aircraft, in this case a Mooney 201. Windmill RPM was
about 800, and no amount of pulling on the prop control would change
that RPM. Obviously, if the RPM doesn't change, the prop pitch didn't
change, and the glide is not affected.

Jim and I have 'round on this one before, but I stand by my observations.

Well, here's another data point on the same make and model, M20J. I
don't have the numbers to go with my observation, but subjectively when
I pull the prop control back at engine idle and ~best-glide, it feels
like I just disengaged the brakes.

Yes. That's the way it felt in the 182. I don't have any numbers but
the effect was not subtle. Hence my initial post.

Al wrote:

There is indeed. In my experience, cycling the prop on a windmilling engine
has no effect. I'm talking about a constant speed prop on a single engine
aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no
amount of pulling on the prop control would change that RPM. Obviously, if
the RPM doesn't change, the prop pitch didn't change, and the glide is not
affected.

Certainly seems to make a difference on an idling engine. I expect
that my engine at idle is not developing much thrust (for she'll die
when it's hot once I roll out unless I give her a little gas).

If your engine won't reliably idle, there is something
wrong. The idle is set too low or the idle mixture circuit
is plugged. If it is an injected engine the fuel pump may
have low pressure.


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

"Ron Natalie" wrote in message
...
| Al wrote:
|
| There is indeed. In my experience, cycling the prop on a
windmilling engine
| has no effect. I'm talking about a constant speed prop
on a single engine
| aircraft, in this case a Mooney 201. Windmill RPM was
about 800, and no
| amount of pulling on the prop control would change that
RPM. Obviously, if
| the RPM doesn't change, the prop pitch didn't change,
and the glide is not
| affected.
|
| Certainly seems to make a difference on an idling engine.
I expect
| that my engine at idle is not developing much thrust (for
she'll die
| when it's hot once I roll out unless I give her a little
gas).

In article ,
Ron Natalie wrote:

Al wrote:

There is indeed. In my experience, cycling the prop on a windmilling engine
has no effect. I'm talking about a constant speed prop on a single engine
aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no
amount of pulling on the prop control would change that RPM. Obviously, if
the RPM doesn't change, the prop pitch didn't change, and the glide is not
affected.

Certainly seems to make a difference on an idling engine. I expect
that my engine at idle is not developing much thrust (for she'll die
when it's hot once I roll out unless I give her a little gas).

Ron, is your engine injected?
If it is, you need to adjust the idle mixture to prevent the starvation.