He has the UM T-28. Its not very receptive to modifications or adjustments. It is basically a little fun flyer and not meant to be an aerobat. I have one and its a blast to fly, but very limited in its performance.  It will do a basic barrel roll, but not an axial roll, its too light, has belly weight from the battery, and the thin wings have a good dihedral on them.   The tiny electric motor doesn't torque the fuse either, so no assistance from that.    There is not a lot of throw on the ailerons either, and they are rather slow.