VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   RV-10 (https://vansairforce.net/community/forumdisplay.php?f=4)
-   -   Leaning (https://vansairforce.net/community/showthread.php?t=148119)

dspender 03-28-2017 06:56 PM

Leaning
 
I am in Michigan with OAT10-45 F. MP 22.5 and Prop 23. 3-5000 ft. I lean till just lean of peak at gph is about 11.0. Is this what others are seeing?

dspender 03-28-2017 06:59 PM

I should add, CHTs are about 340 with those settings.

Raymo 03-29-2017 12:46 PM

Though you are looking for a GPH answer, you might also read up on proper mixture operations by John Deakin.

http://www.avweb.com/news/pelican/182084-1.html

Lots of other interesting and educational articles, as well.
http://www.avweb.com/news/pelican/182146-1.html

Aggie78 03-29-2017 01:01 PM

Good info...
 
I can second the John Deakin articles, they were immensely valuable!

Dovetailing with those is a series of EAA webinars put on by Mike Busch on the subject.

Leaning Basics:

https://www.youtube.com/watch?v=_Vfi...GA0Ld&index=42

Leaning: The Advanced Course

https://www.youtube.com/watch?v=X-tK...GA0Ld&index=39

Flying efficiently in a world of $7 Avgas (a little older, obviously):

https://www.youtube.com/watch?v=ZBr6...GA0Ld&index=36

rleffler 03-29-2017 01:06 PM

Quote:

Originally Posted by dspender (Post 1161490)
I am in Michigan with OAT10-45 F. MP 22.5 and Prop 23. 3-5000 ft. I lean till just lean of peak at gph is about 11.0. Is this what others are seeing?

I run a little higher MP, typically 24/23, but GPH is usually about 11. It really depends on the density altitude. I may have to tweak a bit up or down. I've also have the injectors balanced by Don Rivera.

bob

RV10inOz 03-29-2017 04:30 PM

As a business partner with John Deakin, George Braly (GAMI/TAT) and Walter Atkinson, I can also endorse those comments above.

I strongly suggest you sign up for their engine management course (nothing in it for me ;) ) and you will learn how to understand what to do not just be too a single case recipe which only works at one instance.

www.advancedpilot.com

You should fly Wide Open Throttle all the time except when you want to slow down. You would not fly with a dirty air filter so why close the butterfly doing the same thing?

Next RPM is best between 2300-2450 and depending on your engine and prop the 2400 range works well, but pick a smooth "happy place".

Then fly it outside the red box as per the cheat sheet in the article link below. read this carefully and print off the red box / outside the box bit.
http://www.avweb.com/news/pelican/182583-1.html


Red box simulator https://www.advancedpilot.com/redbox.html

Target EGT climbs (again read Deakins articles thoroughly). https://www.advancedpilot.com/tech.html

Hope that helps!

dspender 03-30-2017 06:46 AM

I spoke with Mike Busch yesterday and my take away is as you said; fly with wide open throttle, prop 22-24 and lean of peak. Assure CHTs remain below 400 for my Lycoming. My GPH at those settings will determine % power, ie for my 540 multiply GPH X 14.9 and divide that by 260= % power.

David-aviator 03-30-2017 07:39 AM

All good stuff if you have CS prop.

Many do not.

My take on that situation is MP to 23 or less and you can lean all day to hearts content, will never damage engine and plugs stay clean.

WOT all day applies only with CS prop. Did it all the time with Subby and MT prop worked great even at 2500'. WOT and 1900 rpm provided great efficiency.

Of course engine had knock sensor which Lycoming does not because it vibrates too much. And even if knock were sensed, it does not have brain to adjust timing.

Auburntsts 03-30-2017 08:34 AM

Quote:

Originally Posted by David-aviator (Post 1161820)
All good stuff if you have CS prop.

Many do not.

Maybe in the RV fleet but in the RV-10 world CS is the rule, probably to the tune of 99. 9%.

RV10inOz 04-10-2017 05:02 AM

Quote:

Originally Posted by David-aviator (Post 1161820)
All good stuff if you have CS prop.

Many do not.

My take on that situation is MP to 23 or less and you can lean all day to hearts content, will never damage engine and plugs stay clean.

WOT all day applies only with CS prop. Did it all the time with Subby and MT prop worked great even at 2500'. WOT and 1900 rpm provided great efficiency.

Of course engine had knock sensor which Lycoming does not because it vibrates too much. And even if knock were sensed, it does not have brain to adjust timing.

Well there is hope for the fixed pitch folk. If you have good F/A ratio's you simply lean for about a 100RPM drop. It makes EGT hard to monitor as the EGT changes so much but effectively this is the old 10% BMEP drop the old radial piston airliners used.

Try it out and you will see. ;)

No1fltim 04-10-2017 09:41 AM

Why does a CS prop make a difference?
 
I thought I understood LOP operations but I'm obviously missing something.

Why does a fixed vs CS prop make any difference?

Auburntsts 04-10-2017 10:12 AM

Quote:

Originally Posted by No1fltim (Post 1164378)
Why does a fixed vs CS prop make any difference?

Short answer -- it doesn't with respect solely to LOP ops. However, the previous posts get into concepts of engine ops beyond just LOP.

No1fltim 04-11-2017 06:49 AM

Thanks!
 
Thanks Todd - an engine management course sounds like what I need. Clearly over my head here.

Auburntsts 04-11-2017 07:34 AM

Quote:

Originally Posted by No1fltim (Post 1164624)
Thanks Todd - an engine management course sounds like what I need. Clearly over my head here.

Never a bad idea, but in lieu of a class, the John Deakin's Pelican Perch articles over on AvWeb are a treasure trove of information. Here's an example:
http://www.avweb.com/news/pelican/Pe...-182085-1.html

Once there you can see the links to other articles on engine management covering all phases of flight from startup to shutdown.


All times are GMT -6. The time now is 01:46 AM.