Ron Natalie writes:

Sometimes, and yes.

What makes them asymmetrical?

Spiral is not an oscillation. Spiral is a departure from positive
stability when you push things too far.

Spiral instability.

Absolutely and totally incorrect.

It depends on the aircraft, but my generalization is mostly valid.

You should go read a introductory
pilots book section on flight aerodynamics.

That's the problem with pilots' books: they never go past the introduction to
these complex topics.

Now your an aerodynamics expert?

I've never claimed to be an expert. But I do know something about it.
Asserting or sharing knowledge is not a claim of expertise.

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