I've seen so many posts over the years about tip stall problems with this plane and it is puzzling because the wing is not tapered and not high aspect ratio, and I'm sure it is a standard semi-symmetric airfoil. If you looked at the wing alone it is probably just like the wings of dozens of successful sport models. So it must be something else.

I think the something else is the stab. It looks extremely small. I suspect the stab actually stalls first, then quickly causes loss of control over the angle of attack and a wing tip stalls. I've been tempted to get one of these planes just to try to prove the point. I would measure the stab area and the tail moment and then use the standard formulas to see there is a problem. I bet there is. Then I would build a bigger stab according to the formula. Just as a guess, I suspect if the stab were increased 15 - 20% (increasing the area about 30 - 40%) the plane would be much nicer to fly.

Jim