VFR
I think you will find quite a lot of machines with non teetering heads(fully articulated) have the ability to do loops and rolls, but you are not allowed to perform them (quite rightly so!), I know of an Enstrom 280 performing loops etc!!!!!.Somewhere on the forum is a picture and a thread with a A 350 inverted, cant remember the title though (think it was feb time)
regards
HoverBover