it's called autorotation when a heli does it, the bigger the heli the better, you should go up with the wind if your, blade area+ friction X weight =is not too much, heli's aren't as effective as planes, they take more power to fly so it's not going to be easy but autorotation is using speed to spin the blades where matey is using the wind blowing up for lift than trading some lift to spin the blades, the small 450 makes life hard as there is not much energy in the blades cos they're light, you don't have time to adjust the pitch to get the right balance of lift the head speed,