Good question , as a matter of fact , after I set the wing incadence , I installed a small cable on both wing tips, with a screw run into the end of the main spar. It had a slight hum when doing high speed pass, and it went away after I tied the wing tips together. But my kit thedie cutting and wood were the worst I,ve run into , most the parts were crushed instead of stamped. And a lot of the balsa was harder than Maple so I ended up hand cutting a lot of the parts. If your kit is a good one , you probably wont run into this problem.