This flying is called 3D flying and is the current craze amongst many RC pilots. I used to "try" and fly like this, but I am too old for the reaction times needed and am in the process of selling the last of my RC plane gear. Still got a nice 9 channel TX if anyone is interested, lol. Jokes aside, the planes are 50cc to 150cc on average, they have massive aileron, elevator and rudder movements and are very overpowered. They use 4 differing stick movements at the same time to perform the "rolling harrier" seen in the video and the timing is critical, but even more so when that low. They usually use around 7 channels on a plane that size but it differs depening on what mixing they use on the TX.
It takes MANY MANY hours of practice to be able to do this, infact even for a young "playstation generation" lad, they would take around 2 to 3 years of constant practice to get to this kind of level, for most people they never get there. Amazing to watch as I had a number of good friends who fly like this and compete both in the UK and abroad. Well done to them all
