tHE PROPS WITH THICKER HUBS , TYPICALLY HAVE A PITCH WHICH IS CLOSER TO BEING "CORRECT"-THAT IS , If you used a protractor and measured the back side of the blade at -say 10 points along it's length, you would find, typically, that each of these stations equaled the same FORWARD prop movement in one revolution.
Each prop manufacturer has his own ideas as to what makes up the best combinations of angles.
Some are really quite removed from the theoretically perfectly pitched prop.
Some of the reasoning is pretty good - some - well not that great.
Props which flex , willy nilly are pretty much -worthless.
Props designed to flex and make a specific change as they load or unload -can be great --but on our models -I have not seen any of these --
In running larger engines -at lower revs--we are now typically running engines in the 4000-6000 rpm range, we find that the prop types which work best , are different than the small props we used on models which were revving along in the 8000 rpm range.
It all makes sense tho -at least to me - that these props -which have more pitch, yet really not more relative blade width, work well.
The main reason, appears to be the fact that the models we are using are relatively lighter --and can change speed -with the prop speed -- much more easily.
Bottom line - you really have to try a variety of blades to see where your particular engine/model combo works the best --for you.
All the calculating in the world won't find the "sweet spot" you may be searching for.