I scratch built a 80 inch wing version of a ME 109, based on the guillows rubber band kit. The all up weight was 9 pounds, it took 3 pounds of lead to balance it! thats right ..1/4 of the planes weight was lead ! It flew like a glider though. Later I pulled the 75 glow motor and added a 3 pound McCulloch 25cc weedie engine. Perfect balance