I had the same thing happen today. I have the three cell and cf blades. I was doing a roll and right when I gave it negative pitch, the blades seemed to turn sideways and beat the canopy. All I could do was cut the power and watch it fall. It broke the spindle, bent the shaft and destroyed the canopy. I'm still not sure what caused it because it was flying fine and I had done rolls and loops that flight up til then