Lu. .. .Regarding your first paragraph, I believe that the application of undersling has as much or more to do with minimizing rotor mass misalignment, as it has to do with blade lead-lag. The application of this thread's idea will reduce the misalignments of the blades' centers of mass, aerodynamics, and percussion, etc. etc. There is no argument with your comments about the R-22 head.. .. .I think that the blade attachment is at 40-45% of chord to minimize spanwise bending and/or resist the blade tip's desire to lead. Chordwise, a blade's center of gravity is located ahead of its aerodynamic center; for stability.. .. .President Blowfly:. .. .I totally agree with all that you have said. Stiffening of the blades will definitely add weight to the rotor assembly and for strength, a thicker blade profile will be required, at least near the root. . .. .The bottom line is: Are the disadvantages of a heavier rotor and slightly higher drag worth the advantages that will come from having a reduced mean coning angle plus a reduced range coning angle extremes?. .. .Regarding the R-22 coning hinges, my 'totally unqualified' position is that there should be consideration given for having them physically interlocked. This way they will only perform the function of coning and leave the flapping to the teetering hinge.