Spocia
But any stability (in that I mean a tendency to revert to the original state once disturbed) is provided by the roll (spiral) mode.
An interesting comment with which many would agree….
BUT
I know an aeroplane that in some parts of the flight envelope is statically unstable in roll (as demonstrated by it needs more roll control deflection to stop it continuing to diverge in roll at ten degrees of bank than it does at five).
How does that fit in with your thoughts?
JF