This is where subscribing to heli magazines comes in handy. Model Heli World( the english mag) has been running a series of articles on advanced(for me) 3D maneuvers. Each article covers one maneuver. the piro.. flips were covered last year I think. Russ deaken(sp?) writes the articles with excellent graphics and in the case of the piro. flips gives diagrams of the stick movements involved. I believe that he called the stick movement "stirring the pudding" for the piro flips. I am too lazy right now( today was leg day at the gym) to get up and find the particular month/year. But I'll find it tomorrow.
Back issues are available at a very good price.
www.traplet.com ( I think)
Vince D