Hi Colin...

And for precisely the same reason, the retreating blade sees a higher angle of attack as it 'flaps' down, thereby creating sufficiently greater lift to balance the forward-going blades.

What really gets interesting, however, is that as the forward speed of the aircraft increases, the airflow over the retreating blade begins to flow from trailing edge to leading edge near the hub. The faster the flight, the more the 'rearward' flow moves out from the hub. Or, should
the rotor slow down the rearward blade can completely stall!! (Bad Deal!!)

Bill