versus the Bf 109's fully variable props
I could be wrong but think the early 109 props were fully variable but not constant speed?
The required the pilot to keep twitching the switch to adjust the prop to suit the speed range the plane was operating at?
Or rather the pilot would have to keep the engine speed and the prop aligned with what he was trying to do.
Trying it again
If the Pilot was climbing (low speed but high power) the pilot would have to throttle the engine up but put the prop into fine pitch or close to it (coarser than take off).
If cruising the pilot had to throttle back but manually adjust the prop pitch to suit the throttle and desired speed.
If at full speed you had max throttle and max pitch.
But if you were a turn as the airplane lost speed the pilot would have to reduce the prop pitch with one hand while controlling the plane with the other hand while leaving the throttle alone (?).
CS prop took care of that for the pilot. Somewhat.
Like in the turn the constant speed governor would automatically to reduce the pitch of the propeller to keep the prop pitch at a good match to aircraft speed as the engine was making full power.
This is something often ignored with the 2 speed prop.
In order to get "best" performance the airplane with a two speed (basically one speed/fixed pitch after take-off)
the pilot had to reduce the engine throttle to keep from over speeding the prop. The prop is not operating at anywhere near a good angle if the airspeed in not near full speed and unless the engine is throttle reduced and the engine rpm reduced. Trying to fly a tight turn with the engine running around 20-30% below max power is obviously going to affect the planes turning ability.