>>Oversped fan? What are these guys using, truck repair compressors?
>
>Size doesn't matter ;) It's easy to overspeed even with just a can of "compressed air". Usually any pressure ~1 bar or more above ambient, released through a nozzle or valve, is supersonic:
https://www.youtube.com/watch?v=DfYlLns0elsWho'd a thunk... And what's the speed of sound in that jet, what's the pressure? These things would be interesting to know.
