VRS
Nick and Shawn - I have read your posts and have found them very interesting and enlightening. As a 7000 hour pilot and examiner, I thought I had this Vortex Ring thing sussed. It turns out that I didn't quite know as much as I do now and, as with just about everything else in aviation, there is much more going on than Lofty Marshall explained to me at CFS.
The main point that I note from your discussion is that the larger helicopters with more power and higher disc loadings seem to have significantly different entry parameters to VRS. As a simple operator, instructor, then instructors' instructor now examiner, I have been lulled into the general train of thought that rates of descent more than 300 fpm when below 30 knots are not acceptable. Whilst this is a good policy to adopt and has always kept me well clear of the offending phenomenon, I now realise that there have been situations where I possibly could have achieved something from which I had chickened out.
I will continue to emphasize the 300fpm and 30kt alarm bell as I still feel this is a point beyond which, very careful consideration is required.
Shawn, having taught (to aspiring instructors) and demonstrated
to others how to get into and out of the danger zones, I generally used the downwind approach or downwind hover (at recoverable altitudes), to show how easily things can go wrong. I think the visual cues from downwind help to mask the onset and make the demonstration more effective. In addition, helicopters do not generally "like" being downwind at slow speed and this increases the pilot workload, control inputs and the likelyhood of a rate of descent inadvertantly building.
You readers and writers of Greek flute music have given me something else to think about and I am grateful, however, I think we all agree that exploring the envelope in that direction should be left to those paid and taught to do so under controlled circumstances and for the rest of us, no rates of descent in excess of 300fpm when below 30 kts will keep us in a nice cosy corner of the envelope.
Thank you all for a very interesting thread.
hh