The avweb article didn't mention the bracket type constant speed propellor or the IOC (Integral Oil Control) props.
Bracket type a la Havard (and apparently Bulldog) use external counterweights to drive the prop coarse with engine oil driving to fine.These do run to coarse as the engine shuts down and can often be manually moved back to fine when stopped.
IOC props (on some of the big radials)Have their own oil system and do do use engine oil.
Although the mechanics are the same there is a very basic difference between the piston engine and turboprop. The difference is that most turboprops link the Prop controls to the power lever (interconnect) while on the pistons engines they are completely separate. It is possible to damage a piston engine by overboosting ( oversquare).
Not mentioned in the comments was that on big radial engines the feathering is actually accomplished with a separate feathering pump that drives the prop into feathered postion, normally with a separate compartment in the oil tank (feathering reserve) and a separate line to the CSU.
Feathering pumps develope around 600 psi but even that is not enough to overcome a runaway prop !
During the war the Germans actually put feathering props on some of the single engined fighters.
