Wow, it didn't take this subject long to degenerate to sub zero!

Now, Rusty if you're serious about your slingshot using a single stage rotary, hop in your little rotary powered RV3 and come on down to Treasure Coast Airpark and I will show you how to build a direct drive fan. I have one that I ground tested for 150 cycles at 6800 rpm with a tired 13B. It would be a snap to do a 100 mph fan. Mine's design point was for 250 mph with the inherent penalties as low speed.

I can send you a picture if you're interested.

Bernie