Evan, that model's based on measurements taken from the Academy 1/48 E's hub--since I'm designing to fit that kit's blades, knuckles, etc, it seemed logical.
TBH, I'm kinda cheating, since I'm trying to just design it as a drop-in replacement for the kit parts, as long as it's "close enough"... The hub assembly builds up from 33 pieces, and one review I saw describes the rotor head alone as a complicated model by itself:
-top plate
-axle
-axle retainer
-upper hub
-lower hub
-fixed knuckle (non-folding, points aft in folded config)
-six folding knuckles
-six folding blade mounts
-seven (?)actuator struts (connect to trailing edge of knuckle, and other end slots in between two vertical plates on each arm of the lower hub)
-seven swashplate connector struts
-swashplate
The Academy kit really is a quantum-leap over the old Revell Super Jolly, even taking the differences between S-65 and S-80 into account.