Constant Speed prop
Can someone please give me a straight little paragraph or two on the concepts behind a Constant Speed propeller control. Because while I know (apparently) how to handle the blue lever and to watch manifold pressure and RPM in combination, and adjust the prop accordingly, I would be grateful to actually know what it's doing and can't find a good reference, despite looking.
It is obviously not an actual propeller pitch lever, as the CSU changes the prop pitch itself while the lever stays fixed. I understand the lever changes the governor on the CSU. What's being governed ? It can't be RPM because otherwise it would be calibrated with RPM.