If it had been built with a simple teetering head instead of adding the flapping hinges
Had not been aware of the flapping hinge, always thought it was just your regular Bell type teetering system, having had nothing to do with Robbies, but upon reading thought exactly the same as you
Crab.
So the blade has two axis about which to flap. The head (teeter) and the flapping hinge. Seems a bit odd at first glance.
Would the inability of the blade to lead/lag in such a set up have any role to play?