Again… dont know if this was directed at me or others- but I also happen to have just short of 4 out of 5 years of Masters/BSME under my belt before I had to make a decision as to what I really wanted more in my life at the time.
Not necessarily directed at Newman: But that aside, the “bearing” type I am refering to- the sprags dont actually roll, they slip on an oil film when not engauged. The shaft diam. of an average Turbocharger is not that far off the specific examples I listed, so an RPM based comparison is a fairly accurate one. Figuring that there is going to be a max rotational speed differential of less than 3x from its known current applications, probably far less most of the time, its not an “out of this world” comparison. I also feel its ability to support the needed torque is a much more important specification at this time than its lifespan at high shaft speeds. The higher shaft speed in relation to the released sprags should also pull in lubrication increasing the oil film thickness and actually cause the sprags to move away from the shaft. If anything, I would be more concerned about centrifugal forces acting on the sprags at higher RPM’s preventing them from reengauging the shaft until you pass a lower RPM threshhold on the mechanically driven side of the system.