I lost a H-9 Hellcat a couple of weeks ago. It just nosed straight down from a couple hundred feet....no elevator response at all. Only the third or fourth time I'd flown it. Damage was so severe that I was not able to determine exactly what caused the crash. I gave it a Viking's funeral, and moved on. I'm sure that there will be more unexplained crashes in my future, but I'm not gonna let that stop me from enjoying this great hobby. You should do the same...