Eddy, lets put it this way..A nitro spinner is a wonderfull dream! As I said I did the maths on one back when Scorpion Jr. was on the drawing board and I concluded that one of two things would happen, one, it would take too long to get up to a useable speed (2kg disc, 250mm dia, 15cc motor via a centrifugal clutch would take around 9 seconds to reach full speed) or two, If you did get it there the KE would be in the order of 43Kj!!! and something WILL come apart!(More than likely a catastrophic failing of your machine. 43Kj is somewhere around twice the energy that our lynch powered heavyweight spinner produces!)
At that point, I went right off the idea!!
You might do better in using one to run a cutting / saw blade rather than a KE weapon.
Far less mass, quicker spin up time and no problems with impact shock.
Just some thoughts, I think anyone trying one of these needs to be EXTREMELY CAREFUL!!!