231 Takeoff/Climb Mixture Settings

[mooneykflyer]

Hot topic of debate (at least in my circle).

Some swear by the original POH's =full rich until altitude=, others by the 1400 TIT indication discussed by several Mooney engineers via MAPA.

Let the games begin!

[231Pilot]

Check out Bob Kromer's test flight of the 231 in the sample articles on the MAPA web site.  It is a pretty good article, seems to be objective, and is ONE opinion as to how to best fly the 231.

[danb35]

I'd agree it seems to be a good article, but I'd ignore the 50 ROP recommendation--but that's at cruise, not in climb.

[mooneykflyer]

Why don't you like the 50 ROP he discusses?

[KSMooniac]

50 ROP is almost the worst mixture setting to run an engine, especially one making more than 65% power which is easy to do with a K at any altitude.  40 ROP is the worst.

[danb35]

Quote: mooneykflyer

Why don't you like the 50 ROP he discusses?

[HopePilot]

Would you say it preferable to run at peak than at 50 ROP?

[danb35]

Just about any mixture setting would be better than 50 ROP, but 50 LOP would be better than at peak.  Really, though, it depends on the power setting--at or below around 60%, it doesn't really matter.  More than that, though, and you'll want to avoid the so-called "red box":

• 
  
• At 65% power, use richer than 100 ROP, or leaner than peak EGT.
  
• At 70%, use richer than 125ºF ROP, or leaner than 25ºF LOP.
  
• At 75%, use richer than 180ºF ROP, or leaner than 40ºF LOP.
  
• At 80%, use richer than 200ºF ROP, or leaner than 60ºF LOP.
  

(see http://www.avweb.com/news/pelican/182583-1.html for the source of this data and further dicussion).