Double gyroscope

( Adolf Cortel 2009) Double gyroscope. [ if interested in easily building a double gyroscope from an available toy, have a look of muy new video , January 2022: ] The weels can turn in the same or in opposite directions. When the angular momentum adds it behaves like a gyroscope. However, if the weels turn in opposite directions the angular momentum cancel and nothing particular is observed. This means that the magnitude responsible for the behaviour of a gyroscope (angular momentum) depends on the sense of rotation so, it is a vector