Are there any references to the Vuichard technique in particular how\why it is suppose to work?
The only reference I could find googling is the wikipedia article
The wikipedia article suggests the technique is described in the 2013 R22\R44 Flight Training Guide (which looks like it is only available in hard copy from Robinson).
One question I CAN answer since I started the thread... the only place I've seen is the Wiki article and some things that quote it. It came up because the friend who was with me when it happened - who is also a fixed wing & autogyro pilot and very curious about things in general - looked around and I guess found the Wiki article.
It certainly isn't described in the R44 POH, which I have at home.