Try setting the VelocityZ values to something even more dramatic like 3000 instead of 10:
<VelocityZ>3000 m</VelocityZ>
<VelocityZ>-3000 m</VelocityZ>
<VelocityZ>0 m</VelocityZ>
It's not particularly stable, but it looks really cool.
Nice tweak frankdepinte!