Cut outs for ventilation, basicially just bent flutes out to make scoops, and no ailerons. i have cut control surfaces back to about 3/4 stock size and low rate are set for very small deflection. i reckon the fins on the end of the wings help it to bank coz it flys like its on rails. here`s the big bonus............NO wing flex that i could see. Mind you i did a few rolls and loops at low speed but i was just doin circuits at flat knacker