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Old July 9th 04, 01:09 AM
Victor
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Default Power management on a O-300

How do you normally run your engine on climb, cruise, and descent. Do
you use full power while climbing all the way to cruise altitude? What
altitude do you normally fly on a normal long cross country flight,
assuming you can choose from sea level? How do you cruise, full power,
or do you keep at minimum RPM? While descending do you maintain cruise
power keeping an eye on the airspeed?

I saw this post related to power management on another BB and would
like to receive your comments on it:

In "Ge there Fast" Mode, I'll use a density altitude above 7000 ft,
run wide open throttle and lean for max rpm.

In "no hurry mode", I'll close the thottle about 1/4 inch to shutoff
the full throttle enrichment, put on full carb heat(in winter), then
lean to max rpm, the continue to lean about 100 rpm off max (or as
lean as the engine will allow). Adding carb heat will sometimes
allow a leaner mixture. Now remember adding carb heat enrichens the
mixture, so the two have to be operated together. I'll compare the
power setting to the table to make sure the plane us below 65% power,
since below 65%, a lean setting will not damage your engine (as long
as it is operating smooth (hitting on all six).

I installed a new tach, that gives me a steady reading. At altitude,
I can see about 100 rpm increase from full rich to a mixture setting
for max rpm. On the lean side, I can take 100 rpm off the tach and
still run fairly smooth.

CHT is more a function of good baffling. If CHT check that your
baffle and baffle seals.

I have a single cylinder CHT and EGT. I reference them, but they
only tell what one cylinder is doing, not all six. These old
carbuerated continental are not know for even fuel/air distribution.
I listen/feel for a smooth engine,
- Peak RPM should give about 75 Deg rich of peak EGT
- Lean to 50 to 100 RPM below peak rpm will peak the EGT.

There is a really good article on AvWeb about engine power management.