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Here they explain on how it actually works. Found it all very interesting.
http://www.youtube.com/watch?v=MT1EKA_h8vw&t
Also very interesting is the "Ring Lazer Gyro"
[youtube]http://www.youtube.com/watch?v=xnN6vXIo_d0[/youtube]
Check out their site: http://aviationENGLISH.club/
(Sorry but for some or other reason I cannot get these videos to embed as per normal)
Jan