is the cause of a lot of problems, namely bearing failure just as you state. There was a good deal of safety margin I put into the program but at 10.5:1 C.R. its a bit unweildy. I'm not sure what brand of fuel he was using but that plays a big role, as well as them intentionally spinning it very hard and beating it daily. It was a great test mule though. I think we have all gained a degree of knowledge from this venture.