Stability and Control characteristics of the Early Mark Spitfires

[Crumpp]

No mention of longitudinal instability being a problem...
and an accident inspector:

Really? It was the second major problem he mentions out of the 68 structural failures.

Isn't the instability the fact that the Spitfire tightens its turn by itself without further control input???
The pilot has to stabilize the plane by countersteering.
Like a rear wheel driven car in a power slide around a turn, working, but stable is different.
Today 02:22 AM

Correct. You have to apply a push force when should be applying a pull force. It is called a force reversal.

So a small input becomes an ever increasing acceleration until arrested by a push force. It is a symptom of the instability.

This is a measured by the NACA and a function of the divergent oscillation stick free measured by the RAE.

At high speed, the aircraft acceleration can overcome the airframe's limits to destruction.