Those props are scary...about 6 years ago while I was in Junior High I was bench testing an engine and my mind slipped for a split second and my left hand went into the prop. I nearly lost the tip of my left thumb and index finger, but at the ER they said since I had feeling and partial movement they would sew they up and let them be. This accident turned me away from the hobby for quite a while and I am just now getting back into it. So here I am 6 years later and luckly they all work, I still have scars and a better caution when around a running engine.