Click here to see the blade designs we used for the rotors (propellers). We made nine foot diameter rotors for the brakedrum machines and eight foot diameter for the axial flux pmgs. Dimensions are in both inches and mm.
Below you can see the two brakedrum builders: Gaetan
Ayotte and Dan Whitney using Win's clever technique to create a smooth
curve for the blade shapes with a thin wooden lath. On the right
is Kelly putting his smaller blades through the bandsaw.
After the bandsaw, the next stage was to mark out the 'drop'. Here is Geoff Legg, an intern at SEI, at work.
Martye Lumpkin of Salinas CA decided to carve half sized, and even quarter sized blades to take home with her. In the central picture you can see James Edwards of Boiled Frog Trading Cooperative in Calgary Alberta. You'll have to ask James what boiled frogs have to do with renewable energy.
Above Gaetan works on his 9 foot diameter rotor. He is using 2 pieces of 1" plank glued together to make up a 2" piece. This works but there are some hassles with changes of grain. Below, Chuck Morrison works on a ten foot diameter rotor. His website is worth a visit. He has done some pioneering homebrew and we all learned some new tricks from Chuck.
Here I am holding one of Martye's completed works (very impressed) and here is Jeff Gilbert of Chesapeake Wind & Solar holding a finished blade for Kelly's wind machine.
Kelly balanced the assembled propeller on a centre-punch in the vice, and added lead weights until it would sit exactly level. Those blades ran smoothly and quietly.
Kelly was helped out by Scott Silliman of Pittsburgh PA, and Amy Pilling of Santa Fe NM.
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