A few questions?

[Walter Atkinson]

Originally Posted by Ernie Martin

I go to 25/25 at about 500 ft and leave the throttle there until the descent, so at cruise MF may be as low as 19; I normally lower RPM to 23 or 24 when I get to cruise altitude.

Ernie:

After TESTING various methods in both an advanced engine test facility and on a very well-instrumented airplane (read pressure transducers, etc) you may be surprised to discover that the easiest one can be on the NA engine is to leave the throttle wide open and the prop full forward until reaching cruise altitude and then setting whatever cruise setting you choose.

1) The internal cylinder pressures at WOT/max RPM are lower than at 25/2500. CHTs will be better controlled.

2) Lean to the Target EGT as you climb.

That gets one to altitude quicker, saves fuel and is much easier on the engine. Based on the hard data, the notion that reduced throttle settings during a climb are "babying" an engine are misplaced.

[rotorgoat]

That's interesting. I don't have an operating manual for the IO-360 but typically Max Power is limited to 5 minutes on a good number of engines. I'm not sure what Max RPM is for this engine either but it seems that higher RPM usually plays a significant factor in engine life.

[Walter Atkinson]

Originally Posted by rotorgoat

That's interesting. I don't have an operating manual for the IO-360 but typically Max Power is limited to 5 minutes on a good number of engines. I'm not sure what Max RPM is for this engine either but it seems that higher RPM usually plays a significant factor in engine life.

Any engine that has a max power time limitation should be adhered to. If none, max rpm is OK.