In the video you can see that the right aileron was up at the start; that appeared to be the cause of the initial right turn, then I think he over-compensated and crashed in the other direction. Since he probably didn't intend full right aileron, I wonder if a servo was faulty. It's possible he also lifted off early, but that doesn't explain full right aileron at the beginning.

I completely disagree that over-powered airplanes are easier for beginners. I taught myself with planes that anyone now would call under-powered. With a buddy box and an experienced instructor it's a different story, because the experienced instructor can use power to get out of trouble, but for a beginner high power is as likely to CAUSE trouble as get you out of it.

I instructed with a Tower Trainer and would never consider using a ball bearing 46 on it. It is not very big and flies extremely well with a lowly 40LA, including vertical pull outs next to the tree line in tight situations.

For a Sig LT-40, which is much larger, a 46LA was fine, but I liked it better with an old OS 40 FSR, which is more powerful. To me, as an instructor, that was plenty of power, and that's got a 70 inch span.

Jim