An injection manifold directs a stream of air through a lengthwise slot in the turbine shell. The stream flows between the disc spaces in a spiral path and eventually exits through exhaust ports located around the center of each disc. This coil of moving air "drags" the discs in a circle causing the rotor to turn.
You can build this project using cardboard sheets obtained from end covers of discarded 3-ring binders, hand towel and bathroom tissue rolls, a high speed electric drill used as a lathe, basic hardware, white glue and simple hand tools.
Caution: Anything attached to the rotor axle must be securely held in place. With a sufficient air pressure, the turbine rotor can spool up to several thousand RPM in just a few seconds!