I flew the larger one of these today, and with the C.G. set at recommended the plane had two problems.

- Not enough down thrust. We added 2 degrees of down thrust.
- Still tail heavy. The C.G. on the larger ( the smaller plane will also be proportional ) plane needs to come forward at least 1 - 1 1/2"!!!

That tip stall you saw was because the C.G. is too far back. The plane was at stall speed w/o dropping the nose. I had exactly the same experience as you.

Try moving it forward and perform a mid power turn. The nose may drop a bit, but there should be no adverse yaw. Then at altitude, try slower and slower turns. When set properly there should be almost no tendancy to drop a wing in a stall.