...you can find at #218 http://www.inter-corporate.com/forums/FieldPropulsion.Engineering.html .A common hoop(see lab demo) is fastened at the bottom position.A pulsatory hoop has a "reverse" fixed location:upwards.That's all.In a certain way it's another expression of a Watt's governor.So ,thinking about a temporary store-restore system of the rotational momentum,pulsatory hoop gives hope for a greater " playground",due to his "reverse posture".All the Bests!/Alex