Some of the statements on this thread seem to assume different things. For example:
Originally Posted by Graviman
Nick, my confusion comes from the fact that XH-59 had two rotor speeds while X-2 has apparently a variable rotor speed.
I think it has been stated previously in this thread that the XH-59 had two rotor speeds, and I interpret the discussion as though there were a physical gear change, like a motorcycle or car. This seems odd. Then we get:
Originally Posted by NickLappos
Dave is right, the ABC cruised in autorotation at about 250 knots. The collective was raised so that the rotor rpm settled at about 88% Nr.
Now, does this imply that the gearshift was connected to the collective? Or they used collective pitch to control RPM just like any helicopter in autorotation? Or is there something more sinister going on, like the CVT (continuously variable transmission) in my 1971 Harley golf cart?
-- IFMU