I am still learning 3d with my funtana x50 and to say the least, am having a blast. I did last weekend have a strange thing happened. I think i know the problem but want to consult with the experts just to make sure .
Struggling to hold the plane in a hover, the plane stalled out but this time the right wing dropped and the plane king of fell into a difficult to control dive/spin. Kind of like a blender but not to that extreme. I was able to get out of it and imidiatly landed. I am thinking i could have been one of four things

1. Pilot error
2. Wind shear
3. Glitch
4. Too far foward CG

The most foward recomended cg was 129mm. But that had been balanced before i added a pump and a more suitable (heavier) size motor mount for the large engine. I also added an apc 16-4 along with it over a wood 15-6. Never tried rebalancing it. The plane does seem to stall pretty easily at slow speeds.

Anyway, I am switching back to the stock muffler from those stupid pitts mufflers [:'(] and in the process removing the pump. I will definatley rebalance the plane while i am at it and i think i will shoot for 130-132mm as my balance point.