Guys,

In two weeks I've lost two Dyanamax fans running on an OS .91. I looked at the crankshaft and it seems straight to me. What could be causing it?

The first time, the shroud and all stators broke. This time, only the rotor blades are gone. I cranked up the engine and set the mixture. I did not feel any strange vibration. I lined up with the runway, accelerated to "Vr" and all sorts of crap starting coming off the exhauast (impeller blades). I was able to do a soft landing on a grass field, and the airframe didn't suffer any damage.

I'm starting to think FOD. But I don't know, the runway looked pretty clean to me.

Any ideas?