Thanks for pointing that out, IFMU. I had wondered about control forces for that type of installation. If the blade flexure occurs outboard of the pitch bearing, pitch control moment might become high with lead-lag - i suspect it sorts itself out in flight though. This is also true for a hingeless design, if combined lift&drag force does not always act normal to plane defined by pitch link joint and bearing axis. I imagine this is why hydraulic failure can result in such high cyclic forces for larger machines with say 4% offset hinges.
Nick, how does D3 affect flapback? Being mulling this over while meshing FE.
I can understand about the need to reduce collective pitch when encountering lift though.
I had also wondered about the S-76 twin bi-filars, but finally put it down to the need for increased pendulum mass. Is one tuned to N+1, while the other tuned to N-1?
Mart