Well, what is the stalling speed of a Tiger Moth at the top of a one G loop? isn't it same as straight and level (1 G environment)? The wing doesn't know it's upside down. Or, are we talking in terms of zero G at the top of the loop, in which case how can it ever stall?
The wing (none symmetric) in a Tiger does know it has a negative AOA. Symmetric aerofoils (Pitts?) don't care