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Old 31st December 2011 | 11:59
  #50 (permalink)  
mm_flynn
 
Joined: Aug 2003
Posts: 1,218
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From: Surrey
Originally Posted by shumway76
In a climb at full power, ... I think the chances of being on the lean & therefore overheating side is less because of the full throttle enrichment? - True / False / Somewhere there...
Note added
This comment relates to a typical spam can rental aircraft with no significant engine instrumentation and a carbureted engine.




False.

in a carbureted engine you are unlikely to be able to operate lean, just less rich.

at climb power and speed near sea level you need to be quite rich to keep temperatures and pressures at a safe level. if you lean 'a bit' it is relatively easy to wind up at exactly the wrong point and pulling 120% of max power out of the engine (unless it fails).

at higher altitude (as you approach the altitude you can only obtain 75% max power), you need to keep leaning to best power in order to get book climb and at these lower power levels can set any mixture without damaging the engine (subject to having enough cooling airflow to keep CHTs under control )

Last edited by mm_flynn; 1st January 2012 at 10:13.
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