The right turn tendency is an issue with some NextStars. The one I have did the same thing, and I've heard of several others doing the same thing, but its also a hit and miss since I've flow others that haven't had the problem.

There a several things that can cause this, but the most common for this issue is excessive right thrust. I think one of the jigs used to build them, and the one that sets the firewall, is out of wack. One way to to check if its excessive right thrust is to loop the plane and see how it responds - does it want to roll out? Next try the loop again, but from a dive with the engine at idle. Does it still want to roll out? If yes, the you need to look at airframe issues other than the engine right thrust. If it tracks straight through the loop at idle (which is what mine did), the you need to put a couple of washers behind the right side engine mount to take out some of the right thrust.

Hogflyer