Look at the figures... Pitts say 300+ for an S-2C, Extra quote 400, Edge 540 are saying 420.
I was told by some people who know what they're talking about, that the days of biplanes are over, as they roll too slow because they have "all that wing". I would have thought smaller length wings and 4 ailerons would equal more roll, but apparently not.
I saw the Russians practising at Sherburn, and their Sukhoi's were rolling insanely quickly, even in slow-flight.
So, as far as I know (now) monoplanes, with pretty much full-span ailerons, are the fastest rollers.
Hopefully someone better informed (I've only flown some of the more mundane acro types) can shed some light.
