John Faith's Compressed Air Turbine Project 

September 25, 2002

Thanks to John Faith in Seattle, Washington for sharing these photos of his project. For more information, contact John at jfaith@nwlink.com  

I have built a small turbine with 2 inch diameter discs, and have run it with compressed air, but have not done any measurements for RPM or efficiency. The outlet holes in the discs were just done with a drill (not laser cut), which means the discs are easy to make. The design also uses no washers or bolts to join the discs, which I'm guessing is OK for such a small diameter turbine. I use a Sherline mill and lathe.

There are a couple differences in my turbine versus what I've seen recommended, mostly to simplify the design:

The exhaust holes near the center of the discs were just made with a drill versus a more complex, laser-cut shape. I used two sizes of drill to make eight holes per disc.

There are no posts to hold the discs together, but I've just used a threaded (6-32) bolt for an axle with nuts on either end. It seems to hold it together OK.

On the inside exhaust half of the casing I made ridges to get a labyrinth seal type geometry. From what I've read in the TEBA newsletter, I'm not sure these are needed. The disc facing these ridges is plain, again for simplicity (and to save time).

All pieces were made with scrap aluminum from parts of Xerox copiers.

I haven't made any power or speed measurements yet, but I have connected it to a DC motor, generated a bit of electricity and turned on some small lights. I'd eventually like to make a larger unit for use in a hybrid-electric vehicle. Lots to do!

John Faith