trigo(at)mail.telepac.pt Guest
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Posted: Tue Sep 20, 2016 4:15 am Post subject: Lycoming Engine School (was PCU 5000 able to command low rpm |
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Bill
You mentioned “Lycoming engine School”, does that still exist?
Regards
Carlos “wishing to learn all about Lycoming engines” Trigo
De: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] Em nome de Bill Watson
Enviada: Tuesday, September 20, 2016 12:19 PM
Para: rv10-list(at)matronics.com
Assunto: Re: PCU 5000 able to command low rpm (<1700rpm)?
On a similar note, I avoid running at or below 1000 rpm to avoid lead fouling, which I am led to believe can happen even when fully leaned.
While attending Lycoming Engine School, I followed up with the instructor after his lead fouling discussion and came away with the understanding that lead build-up will occur anytime combustion chamber temperatures drop below a certain point. He emphasized that it happens very quickly based on some testing he was familiar with. He mentioned that that the practice of pulling the power off at touchdown and leaving it there during the rollout is enough to form visible deposits. By the same token, heating things up above the critical temperature soon after will cause most, but not all of those new deposits to quickly evaporate away.
This write-up from Shell seems to support that thinking.
As a result of the same thinking, I've never practiced engine out descents with the power pulled all the way and the prop slowed anywhere near 1000 rpm.
This former fixed pitch jockey handles the prop cycling task by setting the power around 1500 rpms before cycling the prop. During the cycle, the rpm drop just hits 1000 rpms as I move the control forward. And I try to not to imitate what I've seen some CFIs do by slamming the prop control this way and that. On my engine a slower steady hand will do.
I've never been told that it's hard on the prop and don't believe it is. I have been told that I'm both checking function and forcing some warm oil thru the controller so that it performs as expected during takeoff. Now I'm thinking the main task is just to make sure it works without spraying oil all over the place but honestly just don't really know. I just do it.
Bill "glider guider at heart that has learned to love that big 'ol 540" Watson
N215TG
On 9/19/2016 10:26 PM, Carl Froehlich wrote:
Quote: | Quote: | I don't recall how far it will pull down the RPM - I only pull the propuntil a get a slight drop to make sure the governor is functioning. I wastold (correctly or incorrectly) deep run up cycles are hard on props. --> RV10-List message posted by: Tim Lewis <TimRVator(at)comcast.net> (TimRVator(at)comcast.net) Thanks, Carl. I want to make sure I understand your reply correctly. I do my runups atI don't recall how far it will pull down the RPM - I only pull the prop | 0 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 1 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 2 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 3 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 4 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 5 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 6 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 7 Quote: | I don't recall how far it will pull down the RPM - I only pull the prop | 8 |
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