I've been pondering for a quite awhile whether one can knife edge a Robin 2160... the main thing that has been on my mind has been the ventral fin. It's a rather flimsy affair (as I remember, a hollow composite skin, possibly riveted on, and has no internal rigidity).
Instinct says that it's going to get a pounding during a knife edge, but then again that's probably true during a slip or some of the basic figures like a snap roll.
There's a seperate question as to whether you can knife edge a basic aero machine like the R2160, but I'm more interested in the theory at the moment. The practical will have to be dual with someone who knows how to do it.
