Question for the helicopter fans???

"Andrew-S" I-Still-Hate-Spammers@Sorry-I had-to-leave-for-bit.com skrev i
en meddelelse ...
The other day one of the police departments that I work with mentioned
that
another PD aviation section had an "overspin" on their helicopter.. I was
going to ask at the time what an overspin was but I forgot... So my
question is what exactly is an overspin??? I checked the web and the
answers I found where not exactly enlightening...

I'll venture a guess:
The rotor presumably has a maximum rpm. It is possible to overspin the rotor
if you decend very rapidly . .
A Police-helicopter can do that when they decend to check occupants in cars
they are persuing - or if they have an engine failure, in which case you
spin-up the rotor during the decend to make sure you have lift enough for
the landing.
It's called "autorotation" - I've tried it as a passenger in a Hughes OH-6
during a training flight, pretty scary.


Regards Alf