I'm not sure if this is a bug or something I just don't understand about flying helos. Sometimes the throttle seems to act normally, ie. pushing the throttle up makes RPMs go up and makes the helicopter go up. But then sometimes when I push the throttle up to full the rotor just stops. Sometimes it's a gradual reduction of blade RPM and I can safely land before it dies, usually it just stops dead in mid air. Restarting the engine doesn't seem to help.