Once I snapped a top flite gold texan on takeoff. Rebuilt, had a VERY experience flier do the second "maiden." ended in a controlled crash landing. repaired the landing gear and wing bottom. Then, through RCU, found out that the kit recommended CG was about 1 1/4 inch too far aft. I moved the CG up by that much, and it's been flying ever since--so I don't claim that one, although it did happen....