Guys...the whole heavier prop is all about flywheel effect. Think about the tools they use in space. Since there is no air ( there for no friction), & no gravity, the drills they use must have a weighted motor turning opposite that of the "tooled" end...otherwise...they could never get any torque on the bolt/screw.

If you were to (hypothetically) hover an aircraft in a vaccume (yes, I know its not possible, but stick with me), after some period of time, the airframe would be spinning as fast as the prop, and therefore, the prop wouldn't be spinning at all in relation to the aircraft.

Now, with that said...we are not in a vaccume and we must think about air resistance of the wings, tail & airframe. All of these factors will limit how fast the aircraft will spin while in a torqe roll.

The heavier the prop, the more influence it will have on the airfram & wanting it to "match speed" with the prop. Also, a larger diameter prop will have the same effect since the tips will be farther out & therefore more of a flywheel effect.

This is not necessarily scientificaly correct & I will not try to explain all of the physics behind it...since frankly, I dont know them all!!

Just how it works out in my head (which could be a scary place for anyone else).