Check this out. Got it working on helo props now: (click to view video)
The Cobra featured in the video has dynamic shadows for the props that move! I couldn't make the shadow props engines because geometries that are directly part of the engine don't rotate. So it would have to be something addTemplated onto the engine. However this goes past the max one child object limit for dynamic shadows. So they were made rotation bundles. They have the continuous rotation speed on them so they will always spin at a minimum speed while using thrust will speed them up in tune with the visible propsl
The shadows will never completely match up with the visible prop. but it's better then the dynamic shadow looking like a tad pole.
If you look closely, I made a shadow for the rear prop as well. Since synchronization isn't as important, there will be no network info on these.