Whilst I have to confess to being mostly a fixed-wing bod, I'm doing a PhD in my spare time and my PhD supervisor, a thoroughly clever chap - Chartered Engineer
and mathematician - is one of the 2 or 3 leading experts in the UK in Helicopter blade dynamics (I think he's the chap who cracked the cause of blade-sail about 15-20 years ago). If you'd like his contact details, drop me an Email. If he hasn't any such video or information, it probably doesn't exist. (Whether he'll talk to you is another issue, but that'll be your problem
)
G