RE: Scanner + tire = WRITE OFF
Our field is surrounded by farm land... at one time the farmer was pressing straw bales at the right side of the field... normally these bales end up flat on the ground when the leave the press... but of course there was this one stubborn bale that decided to stay upright, right smack in the middle of my landing approach.
I was flying my trainer in those days... needless to say the reflex to avoid that thing wasn't there. It was a good excuse for me to build a new wing to replace the crappy ARF unit.
So Dave is right keep your field clear... anything that can be hit, WILL get hit.