You are in IMC, when *everything* fails! Now what?

i think you also need to restrict vertical movement of the pendulum's fulcrum
(and therefore vertical translation of the pendulum), which is not practical in
an airplane that can move in 3 dimensions. Regardless, just in keeping the
pendulum swinging, you probably have as much complexity as a gyro.

Michael wrote:

"Gary L. Drescher" wrote
Two differences. First, the ball is not given a shove to keep it
oscillating back and forth even when the plane is going straight (any such
oscillation damps out almost instantly). Second, the ball is constrained to
move in only one plane. The idea of the pendulum is to start it swinging
side to side (say, east-west if you're heading north) but let it move
freely; then, if the plane yaws, the pendulum is still swinging east-west,
so the yaw is detectable. At least in principle.

OK, now I get it. You're using the principle that the plane of
oscillation in a pendulum is rigid in space, just like the plane of
rotation of a gyroscope. Sure, that makes a lot of sense. Should
work just like a gyro. Only issue is how you're going to keep it
swinging. You would need a drive system and an escapement.

Michael

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