vrhc.co.ukvrhc.co.uk/Heli History/1980/1980-02 - Hovering about.pdf · known as...
2
vrhc.co.ukvrhc.co.uk/Heli History/1980/1980-02 - Hovering about.pdf · known as "whirling" between the bearings and So reduces the required number of bearings. This ' 'whirling",
