Surprisingly many here with the impression that wind-direction has no effect.. at least during practise VR, ie. ''onset VR'' and that's what the tread is about ''When practicing vortex ring.....''
As a flight-intructor I used to do this demo and practise onset VR with the students. If you enter full VR, it is almost impossible to recover from it without loosing 1000's of feet, and frankly that is a too great risk taking, when the point of the exercise is to recognize the symptoms of VR and aviod getting fully established.
I did it at 2000ft into the wind, and turned 180 degrees.... what was happening to the ground beneath me, was irrelevant, however the extra couple of hundred of feet lost during the exact same recovery-procedure was the interessting part of the exercise...
Now, allthough the helicopter don't have a mind of itself, I do!
I think it has been discussed more in detail in an older tread as well.
Cheers