109 prop pitch (rpm) and the supercharger

[Crumpp]

What he is talking about is doing the same a CSP does automatically, a controllable pitch propeller has to be done manually.

Fine Pitch to maximize rpm and coarsen the pitch to maintain rpm as speed increases.

If you don't lower the pitch, the propeller will begin to drive the engine and you will lose performance.

A given manifold pressure and rpm as listed in the POH will deliver the maximum performance for the condition flight listed. The pilot must maintain that rpm by controlling the pitch.

I have my pitch control set on a slider for the Bf-109 and adjust it constantly to maintain the desired rpm.

What I take from this:
1. The prop-pitch manipulation had direct impact on air-speed.
2. This technique was used BOTH at high altitude AND at low altitude in the climb, and had an effect in both cases.

You are making the right conclusions. The basics of operating an controllable pitch propeller are given above.