The area I have in my back yard is 50' X 100'. I can fly circuits with tail motor helis with room to spare. These include Honey Bee CP2, Blade CP and CP Pro, and Walkera 22E. When I try that with the Trex450SA, Black Hawk 450 and Venom NR3DXL it gets spooky small because I'm not very good yet at keeping the speed down on those. Hovering, side to side, front to back and piros aren't so bad, but these things are slippery and when you go to FF they can speed up pretty quick. I just ordered a KingV2 so I'll know next week if it's the chopper for the back yard (without a tail motor).