the youtube inbeds aren't working? well here anyway. I saw a fourstroke backfire, and kick a prop off once ..slapped the guy starting it right on the face..he was lucky it didn't go in like a knife..I also witnessed a KNOW IT ALL starting a plane in pits..( he knew better)..the prop popped off and almost ran forward about 4 feet and sort of spun and hopped in the dirt, smacking his field box a few times..it was like something out of a cartoon...