Zero speed auto > Hover (without gaining airspeed)

[NickLappos]

Matthew,

Please don't confuse ROD in autorotation with ROD in powered flight. In autorotation it is IMPOSSIBLE to get VRS, because there is no rotor downwash. The flow is going UP through the rotor, and is powering the rotation by what is called the "windmill brake state" where the rotor is a pinwheel. Any vortex pattern from the rotor is swept up and away from recirculation. There is no downwash to get captured and recirculated through the rotor, thus no VRS.

When Thomas talks about "not enough time" he is referring to the very brief event at the end of a touchdown autorotation where the rotor is recovered from autorotation to a powered operating state (by your application of collective pitch), with or without engine power applied just prior to touchdown.

I think you are right about the terminology, Autorotation is what the rotor does, engines on, engines off or engines missing (autogyros!)

I don't agree with thomas about the distinction between IVRS and VRS. The loss of control and lack of response to power demands that we experience in underpowered and low control helicopters is not because VRS removes ALL control and climb. It is because VRS removes more than those helicopters have. The data is clear and available to support this. To support Thomas's point though, the distinction is theoretical if you are in a typical training helicopter.