One experience I can share here is the feeling of a just a "lack of security" when looping an ac with an open cockpit. I have only ever flown aeros in two open cockpit types; the good old T.21 glider and the DH 82A Tiger Moth. Going over the top of a loop was never quite the same as doing the exact same manoevre in anything else that I flew that had a canopy and I always had a desire to check my harness very carefully when doing my Hasel checks
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The psycological difference of not having 4 or 5 mm of plexiglass was very real. It was never enough to stop me aerobatting but the feeling was very much there.
MB