Outwest - very brown trousers on that last event I am sure
NigelH - did they do a comparison of the Vuichard vs 'standard' recovery? When they used the Vuichard, did they recover in 50'?
Kiwi500 - I don't know, other than using Nick Lappos' graph, if you can put numbers on it.
However, you could liken it to a FW stall in as much as there is light buffet, which gradually increases if you don't recognise it - it gradually worsens and then finally gets to the nose drop/wing drop stage which would be roughly the equivalent of IVRS going into full VRS.
The 30 kts 500'/min RoD figures have been taught for many years as a way to avoid even IVRS but they were based on low disc loading helicopters. Each aircraft will have different figures based on its disc loading and even they will vary with AUM and DA.