The illustration in the book was enlarged to the size that I wanted to build the device, so that I could simply take measurements right off the picture. For your reference the rotor is about 2 1/2" diameter.
Finally on the 19th of May it was completed, but I simply could not get it to run as a motor. Then this morning at the suggestion of my friend Paul Spencer, I checked the wiring connections, and I had two of the wires connected wrong. Soon as I exchanged them it took off running like a champ. Here is a video. I have no idea what caused it to slow down near the end, perhaps a poor connection to the power source or something?