But we know that doesn't happen - for example when you push the nose down to transition to forward flight (thereby raising the TR) you don't get a roll to the right even with excessive amounts of nose down.
Well, that's a dynamic situation with all sorts of stuff going on - collective, cyclic and pedal inputs all being made by looking out the front and reacting to a sight picture, inflow roll, flapback etc, so it's a fair bit different to a stable hover situation which is what the discussion was based on.
hence as Nick Lappos said in a previous post some 10 years ago, the placement of the T/R relative to the M/R head is only slight.
Fair enough, the diagrams are not to scale, but they illustrate the forces and where they act. Nick didn't say the effect was slight, he said it had nothing to do with it, which is what I'm at odds with.
A force diagram is pretty straightforward, as are force couples. If we're having trouble with this idea, then does anyone have dramas with thrust line in a fixed wing, for example?
A high mounted engine with respect to the centre of pressure (drag wise, whatever the aerodynamicists call the point where drag is said to act, vertically speaking) will cause a nose-down pitch when power is added. If the engine is lower than that point, you'll get a pitch up. Same sort of thing.