"We had a similar problem a while back. It was due to the fact that we connected some of the ESCs wrong and everything looked like it was spinning properly, but when we took it for a flight it flipped over.
Have you tried testing it suspended between…"

"So, after a quick search I found that it not only depends on the center of gravity, but also the center of pressure. 
http://exploration.grc.nasa.gov/education/rocket/rktstab.html
So now the question to answer is whether the center of pressure of…"