RE: Propeller acts as brake?
I totally agree that a slowly turning propellor generates drag and your explanation for it BUT and I am sure you could see this coming
if the prop is stationary then the negative AoA is greater- so why isn't the drag greater? If the drag does decrease when the prop is stationary, then you must theorise that at some point there is a change of aerodynamic regime over the prop. At what RPM does that happen 1000 RPM?- 100RPM? - 10 RPM? -1RPM?
I have never had an answer to this and think that is is one of those assertions that everybody believes is true because everyone says it is.
Frankly, I don't