Hi I have assembled and built an Aerotech Int'l Mossie and if was a very nice, fast and stable plane to fly. The takeoffs are very smooth once you learn to control the torque. I had a couple of Saito 56 4 strokes in it at first then I switched to a couple of YS 45's. She flew beautifully with both engine configurations. The CG outlined in the plans is the setting I have used and they were fine. One thing to remember with this plane is KEEP THE SPEED UP! Because of the massive taper in the wing she will snap if you get too slow. I lost mine due to radio failure. I have a faulty Tx and I watched my Mossie fly away (straight and level) until she was a tiny speck then it snapped in and was a total write off. I have retired the Tx. (That is another story).