Flap back
Hi there,
I believe that flap back or blow back as you call it has more to do with the relative velocities of the blades rather than translational lift.
If you break it down you see once you start moving the advancing blade with have a greater relative velocity than the retreating (due to adding and subtracting the airflow velocity) this increase in velocity causes a increase in lift/rotor thrust and the advacing blade flaps up (in the case of moving foward it begins its upward movement 90 degrees before the front of the disc to arrive at its highest point over the nose of the aircraft)
So precession has taken place. This can also be seen when hovering with some wind over the disc, if a climb or descent is initiated the disc with flap back with a climb and foward with a decent (again due to the different relative velocities of the advancing and retreating blade)
As for translation if the front of the disk was in 'clean air' you still get the roll to the right with the higher inflow angles at the rear of the disc.
Just my thoughts
Daver_777