With the top of the wing gone the aileron was getting nothing but "bad air" from all the turbulance and was probably fully stalled. You were probably using plenty of up-stick to keep that side of the wing level and it had no more to give.

Torn covering from powered dives killed a lot of pilots in WWI.

Can't say what happened to the covering?? I've seen panels spontaneuosly explode with a "BANG" during winter flys when the temp is near zero F but that's usually a single tear. It shouldn't happen to a sane pilot.