Back when I was still flying helis, I was running up my Ergo 60 to a high idle while crouched behind it to observe something. Suddenly, the engine just died as I felt a sharp pain in my left gonad. In 30 years of flying R/C, the very first time I have EVER had a glow plug come loose from an engine and blow out, it hits me in the nuts. Damnest thing! Better wear a cup!