Rotor Hub Review: Sikorsky S 34

Also known as the "H34 Choctaw" within military ranks, this helicopter has an interesting rotor hub assembly. Originally it had a large radial engine, but I have seen a few that have been brought to life and uses a turbine power plant.  The lead/lag axis utilizes a heavy hinges with vertical trunnions. Usual lead/lag hinges that I've seen are at the blade root or some type of flex beam inside of a couple of torsion bars combining lead/lag with flapping as seen in the Twin Star. But, I'm not an expert. Just thought it was an interesting set up.