Question on prop cycle

[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

[Mark Hansen]

On 04/23/06 13:14, 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?

There's a very good article on AVWeb by John Deakin regarding engine
start and run-up, which includes a large section on prop cycling (near
the end of the article). You can find it here:

<http://www.avweb.com/news/columns/186619-1.html>

Note: You have to register for access to AVWeb's articles, but it's
free, they there is a log of great information there.


--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

[Clay]

Go by the book recommendation.
The one thing you don't want to do is to let the RPM drop by more than
around 300 RPM. This puts undue load on the engine.

[Robert M. Gary]

> The one thing you don't want to do is to let the RPM drop by more than
> around 300 RPM. This puts undue load on the engine.

Are you serious? How much load can you put on an engine that's only
producing 10% power?
-Robert

[Newps]

Clay wrote:
> Go by the book recommendation.
> The one thing you don't want to do is to let the RPM drop by more than
> around 300 RPM. This puts undue load on the engine.

If that's the case you better never actually try to take off.

[Will]

>>>Are you serious? How much load can you put on an engine that's only producing 10% power? <<<

I think the engine is making more than 10% power at 2000rpm (fixed
pitch prop) during the runup. Don't know how much, but it's gotta be
more than 10%.

[Robert M. Gary]

> Don't know how much, but it's gotta be more than 10%.

Maybe on a fix pitch, but I doubt it on a constant speed prop. It
doesn't take much power to bring a constant speed prop up to full RPM.

-Robert

[Denny]

Nyaa, do it like some pilots at my airport do... Taxi out to the hold
short line, read the POH thoroughly word for word, dial every frequency
on all radios to be sure they are working, meticulously go over every
instrument on the panel, now that the exhaust valves are approaching
white hot go full throttle and cycle that prop at least twenty
times..... Then hang around the pilots lounge and whine about losing
another cylinder, "third one in the past 18 months.. I don't understand
it."...

[Robert M. Gary]

> I think the engine is making more than 10% power at 2000rpm (fixed
> pitch prop) during the runup.

Hey wait, how do you cycle a fixed prop?

-Robert

[Clay]

Just going by what I have read in many manuals, what I learned in
schools, siminars and from talking to factory reps.
Just follow the engine/airframe recommendations and you will be ok for
take off.