Yep, lifting, forgot about the down force on the elevator, without which the CofG would have to swing even further out the back until the couple it created with lift acting at the head stopped the motion.
Hi crab. The assumption I think you and Nick are making that I don't agree with is that every force should be thought of in relation to where it's acting with respect to the CofG.
When we change the forces acting on the helicopter, we don't necessarily make it move around the CofG, and there's no reason why it should - turns around the nose, tail or mast are easily done with different combinations of pedal and cyclic, for example.
In the rolling plane, it's the balance of forces as per that picture I drew that will determine which way it rolls and how far it goes.
You guys seem to be considering the CofG as the pivot point around which everything happens, whereas I'm looking at it simply as the point through which the weight of the helicopter can be said to act, and in that regard it's just another point at which force is being applied to the whole combination.
I'm talking about force couples, as um...lifting referred to.