Barnacles vs. manifold pressure

[joe_db]

A clean prop makes a big difference. If you get a vacuum gauge it will be obvious when it needs cleaning and mine really did!
Absent the vacuum gauge, it is not always as obvious why RPMs or speed is off.

[ronstory]

Great data and thanks for sharing.

It seem seem your voltage is a bit low for a cruise RPM... is that planned or something else?

[joe_db]

That is at the end of the string from battery to the ignition switch then to the engine and then up to instruments. Depending on the stage the regulator is in, it is 13.8 to about 14.2 at the battery.
I have yet to check how accurate that voltmeter is, the reason it is there is so I can see if the combiner is on or not. I will get around to checking the voltage on my digital VOM and seeing if there are any drops at some point.

[ronstory]

Cool. I get 14V at idle and 14.4 running and that seems to work well with my topped off batteries.

[sastanley]

That is at the end of the string from battery to the ignition switch then to the engine and then up to instruments. Depending on the stage the regulator is in, it is 13.8 to about 14.2 at the battery.
I have yet to check how accurate that voltmeter is, the reason it is there is so I can see if the combiner is on or not. I will get around to checking the voltage on my digital VOM and seeing if there are any drops at some point.

I find the same thing, although I have no fancy combiner or anything. The voltage at the end of the ignition circuit is always a bit lower than the voltage I am reading from the battery selector switch, which is another gauge at the nav station. I just use the voltmeter in the cockpit to tell if the alt is working.