Hi CRAN,
However an absolutely rigid rotor is physically unrealizable and therefore some flapping and hence 'some' flap-back will occur (the exact nature of it being dependent on the blade dynamics). The extent of this flapping will depend on how stiff you can make the rotor and still get off the ground."
I agree that absolute rigidity is unrealizable. My thinking is to make the blade as rigid as is feasible, then; a/ mold it with a slight downward curvature, or, b/ give the tip some anhedral, or, c/ give the pitch bearings a slight negative pre-cone.
The intent is to give the disk a zero coning angle when it is hovering at gross weight and then accept the small deviation (+ & - coning) during flight.