I designed and built a DH Vampire around a Dr Mad Thrust 90mm EDF all went well until I ran it up to full power and then the fan stopped and the ESC went up in smoke,lucky I was able to get it out of the plane before it got any worse, when we checked we found that the fan must have been out of balance and flew out against the shroud, this was my first attempt at EDF is this a common thing with EDFs Mike