Some people don't understand how dangerous the larger helis can be. They had a T-Rex 800 getting the electronics replaced, the owner now knows not to charge his lipo IN the heli. A guy was holding the landing gear and when they plugged the battery up, the tail rotor went full blast and threw the 215lb guy to the floor and then was heading towards him. The owner grabbed it and the tail rotor cut his arm up pretty good, luckily it had the wooden blades, plastic would've cut to the bone, he still had to go get stitched up. I had seen some of the larger helis in action, but when I heard my LHS's owner hit idle up on his 800, I had to step back.....you really can hear the beast wake up.