I have finished the tunnel and run some tests on it and it works well. To see pictures and data, go to http://moodle.kirkwoodschools.org
, go to Aerospace Engineering, sign on as a guest (key: teach2010) and click on the first link under Unit 2 labeled Final wind tunnel pictures and data. I am now working to find a good way to screw the airfoil onto the rod and to make rods with different angles of attack. I'll let you know what I come up with.
One note on the magnet holding the anemometer. The magnet is so strong that it prevents the anemometer from spinning initially. I have started it by turning the fan on then blowing on the anemometer and then closing up the tunnel. I am going to try different magnet placements to see if I can resolve this. If not, I will be able to put the airfoil in the tunnel, zero out the sensors, start the tunnel on full power, blow on the anemometer to start it, close up the tunnel, and run several data collection runs at different airspeeds (by changing the voltage to the fan) while recording the anemoneter airspeed reading and the data probes. To determine the correction for possibly not having the probes zeroed since I moved the test section when I put the tunnel together, I will run a final data collection with the fan off. This will give me the correction factor for all the previous data.
Feel free to share the magnet idea. I'll let you know what else I find out as I work to resolve the issues above.