Unfortunately Franz I don’t really see a way to lighten the model. Other then omitting all the scale details, which at that point would be shame as this model is so beautiful. It builds tail heavy, so you could put everything up front, including the air tanks. However doing that would take up space for the cockpit. I still didn’t add all the scale details and I was nearly 40lbs With fuel. At 40lbs and flying off grass, I really can’t see it flying on anything less then 140.