WRL,
the flapping hinge (Starflex arm)
The Starflex is the method used for the load path for the lead/lag damper (frequency adapter) to reference to the head. As you can see it is flexible in the flapping plane but NOT in the lead/lag plane or feathering plane. It is not the flapping hinge. That is in the spherical bearing.
(Thrust bearing & self-aligning bearing mounted within the frequency adapter)
There is no thrust bearing in the frequency adapter (lead/lag damper, the brown one on the lefthand end of the sleeves in the photo and vice versa in the images). There is a self aligning feathering bearing.
The thrust bearing for want of a word is the spherical bearing which is basically a pile of steel spherical cups separated by elastomer (rubber) elements. This bearing allows feather and flap and lead/lag. (The big black one on the righthand end of the sleeves in the photo and vice versa in the images .) The rubber elements are very thin so that failure of one will be not catastrophic as it would be if it were one big lump of rubber.
