Fortunately we made it -- with only one small dent in the side. But once out on the ice, IT WAS A GAS!. Using a hand-held GPS, we clocked the sucker at 48.2 mph going across the frozen lake. And that was with a WOT engine speed of only 3150 RPM. I suspect the engine speed is being limited by the (overly complicated, built-in, lawn tractor) governor. Once we figure out how to adjust that darned thing, we may get even higher speeds.
I've flown a bunch of planes, but never anything that would make a complete 360 in less than two seconds and then continue on its way straight ahead. This is definitely a FUN machine!
It's pretty clear that we're not going to be flying back and forth from the garage too often. We definitely need a TRAILER. So that's become the current project -- see below.
Probably, it wasn't tightened enough, in any case, the return side of the belt started vibrating and it got sucked into the prop -- which very effectively and cleanly chopped it off! Fortunately, no other damage occured. A new belt was purchased (for a mere $49.95 at NAPA) and we added another shim in front of the prop to allow more belt/prop separation. We also made a belt guide (from 1-1/4" PVC) for the slack side of the belt to prevent this from happening again -- in case the belt starts to stretch and loosen. (I gather this is pretty common).
Also, feedback from other hovernaut buiilders and flyers is appreciated.