yesterday I had some spare time:

piece of plywood
skateboard "truck" (axle, axle mount, bearings, wheel=hub)
7 Compact disks
10 bolts + nuts
16 washers

4 bolts +nuts for holding the truck to the plywood

stacked CD's, cut 4 holes on outer edge (for bolts, to hold CD's
together)
2 holes on inner edge (connection to hub)
5 CD's need their inner hold widened.

put it together. blew on it with the compressor.
approx 4000 RPM

Ok, it wobbles. badly.

today, I went ahead and remade the CD's,
drilling them closer to precise.

approx 8000 RPM

12V no load (with a 6volt motor)
6V with load, 2amps output.

So, I decided to add ONE nozzle:
1/8" inner diameter aluminum tubing
2X4 wood supports

approx 10,000 RPM
8volts, 2 amps loaded

measured with digital multimeter.

Rich