Originally Posted by
jimjim1
(purely intuitively) I would have thought that with the angular momentum on the "small side" that you could easily enough reach up and stop the rotor with your hand? Especially perhaps in the case where the lift was zero - the helicopter on the ground with the rotors running.
Whatever it is, the angular momentum of a running helicopter rotor system is not small.
If it was small, engine-off landings wouldn't work out as well as they do.
Yes, good point well presented.
Even so, small, relative to the lift required to hover an x tonne helicopter does not necessarily imply small enough to stop with your hand :P