A helicopter went over my car today - I think it was a traffic 'copter considering the pattern was making above the highway.
One thing I noticed was the long shaft between the helicopter and its rotor. I saw a similar helicopter on TV the other day being used to chase animals on the African plains (for relocation).
My best guess is that a long shaft increases the ability of the 'copter to hover since both applications might do a lot if that - probably something to do with the down-wash. On the other hand, maybe it’s just easier to walk under the blades.
Is there any reason for a long rotor shaft? I would think that it’d be better to keep it short and lessen the wobble that a long spinning shaft might generate.