Turbopump V1 Shaft Design

 For the shaft design, the carriage came somewhat before the horse with the creation of the rough geometry without any calculations necessarily being done. It was eyeballed off of the relative sizing of both the initial impeller and turbine. Once the shaft geometry was determined, a minimum diameter sizing calculation was done to make sure the shaft would not fail in torsion. Below is that calculation. 

The minimum shaft diameter was determined to be 0.169" in diameter with a 2x factor of safety. The current design has the smallest diameter of the shaft at 0.25", more than enough margin.