Andy wrote:

Anything hanging in the cockpit like a pendulum (or any instruments
working on the same principle) DOES NOT tell you which way is up./snip/

9B

If you are going to take on the school master role, you had better be
right. Current solid state angular rate sensors act like a mini pendulum
or tuning fork - when turned, the pendulum retains spatial inertia.
Foucault, an' all that. Remember?

Brian W