Are model helicopters dangerous?
Most mechanical items are dangerous if operated carelessly. The primary danger comes from the main rotor, and to a lesser degree the tail rotor. Small helicopters such as coaxials may sting a bit if flown into someone. Larger helicopters, such as the 450 sized T-Rex could easily cause a lot of blunt impact trauma and moderate to severe lacerations requiring medical attention, but I suspect not much permanent damage unless the victim were unlucky. Larger helicopters could easily dismember and kill.
