The above gentleman is correct.. to be alittle more direct.. scale and heavier type planes generally have a wing loading of over 28 oz/sq.ft. The average trainer runs more in the 18 - 24 range and a glider runs in the 10 - 12 lb range. You could build two trainers. One weighing much more than the other. The heavier would have a higher wingloading.. it would have to take off faster, would have to fly at a higher speed to maintain the same lift and will land faster and decend faster. In short be harder to fly.