One day at the field this guy walks up to me and asks me out of the blue if I would fly his Nextar plane. Not ever meeting him before I tell him no. We continue talking and about 30 minutes later I decide to take it up for its maiden flight after the full understanding I'm not responsible if it goes down. The plane flew very tail heaving and I quickly ran out of elevator nose down trim. I had to 'manually push' the plane's nose down with the stick and I quickly landed it without incident. What's my point? Even if the manufacture boasts it's ready to fly out of the box many times linkages and CG's need to be adjusted. If you're not experienced enough to do this yourself, a crash is evident. He had some time on the sim, but after our first lesson he surely would have severely crashed his plane as it took a lot for me to get it down safely on its maiden flight. I'd get some help. Good luck and welcome to RCU.