you are right the xr is only supposed to weigh Empty Mass 12,000 kg which equals 13.2 tons. Ill see what I can do. I dont know if its the fuel maybe giving it extra weight. Ill look into it EDIT yep its the fuel. working on it now. EDIT 2 I got empty weight down now working on fuel weight and engine thrust using this for reference on page 76 http://www.alteaaerospace.com/downloads/releases/XR-Flight-Operations-Manual.pdf