after 5 flights I think there is a very good chance your rx battery was dead. I noticed you said it was charged when yo went to the field but didn't say anything about checking them after 2 flights. I check mine EVERY flight but most check after 2 or 3. Most of mine last 2 flights but I don't have any that last 5 flights. I'm not saying the hinging is suspect but the battery seems much more suspect to me. Glad you are able to repair. Kadet MK II's are VERY tough. In fact the Kadet Jr's are very tough also. Very impressive line of planes