Wind Power - ZetaTalk

Tips for Designing and Building a Wind Generator
● Airfoil--There are great lengths that you can go to for designing an airfoil...NASA has some great
information and calculations out there on the net. But all an airfoil needs to do is maximize lift and
minimize drag. You will do fine if you do like we did--find a likely looking airfoil cross section from a
working wind generator blade, and copy it. A power planer makes quick work of carving it, and a
drawknife is great for carving too, especially with the deep cuts near the blade root.
● Balancing--The blades must be very well balanced to prevent vibration. This is more easily
accomplished with a 2-blade rotor than a 3 bladed one. But generally, we simply use a homemade spring
scale to make sure that each blade weighs exactly the same, and that each has the same center of
balance. A simple balancing jig for any rotor configuration can be made with an upright spike that sticks
into a dimple punched at the exact center of the hub. Excess material from the heavy areas can be
removed quickly with a power planer. You'll also need to balance the blade in place on the alternator.
It's weight distribution can be adjusted by attaching lead strips to the blade root.
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Furling and Shutdown Systems
Furling Systems--We use the term "furling system" to describe a mechanism that turns the wind
generator rotor at an angle out of the wind, either horizontally or vertically, to protect the machine
from damage during high winds. Ideally it will keep power output levels near the maximum even
when fully furled. Our early wind turbine designs didn't use furling systems, and we feel fortunate
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