On this year’s course we built a 2F machine but with 16 magnets instead of the usual 12. I have a cheap source of these smaller magnets. The 2F is a “2 metre diameter Ferrite magnet wind turbine” which is documented in my 2F wind turbine construction manual.
The rpm is a little higher than the 12-pole version. We played with adding an extra layer of magnets to one rotor, and got about 15% higher flux density (hence lower rpm) but I don’t think I will build any serious alternators stacked like that.
Most of the blade carving was done with drawknives but I did not get any pics of that. It’s an easier procedure than the one in my Recipe Book and seems to give good results for this size of turbine.
I am very grateful to Kostas Latoufis for coming to help, and for putting up with me so patiently. Also grateful to the five participants for their hard work and good company.