hi
i used the free blade calculator to calculate the the angle of attack and chord for the 1.8 metre tsr : 10 blades.
http://warlock.com.au/1800mmturbine.htm
then i made the blades with the exact angle of attack including the negative ones and exact chord length (approx +/- 0.5mm)
i measured the blade efficiency to be 0.30, which seems to be very close to the typical efficiency of a good 2-bladed turbine (0.3-0.35)
so i figure you need to have these negative angles to achieve high efficiency.
did you or anyone measure the efficiency of the blades made with the MiniCodeOverview.html program?
-Michael