What is "aircraft stability" - IN VIDEO

[JtD]

The Hurricane would not move to trim speed and stay there, it would drop a wing and dive into the ground, at an ever increasing speed. It was unstable in the spiral and phugoid modes and much worse at that than the Spitfire, which did at least a few oscillations before departing for good.
The static stability chart you posted is not at all related to phugoid or spiral modes.