Build turbine base, guess size and number of wire turns for test coil to determine coil size, build stator and test, make blades fit machine.
In the end, TSR, the Tip to relative wind Speed Ratio "Falls Out".
Expanding on this: TSR and choice of blade profile are details, making a modest change to efficiency.
But for a wind turbine, efficiency is not a major issue. Unlike consumable fuel, which must be paid for, wind is free for the collecting. So turbine efficiency, like horsepower in a Rolls Royce engine, merely has to be "adequate". If it's a little low, make the mill a little bigger.
There is a broad variety of easy to calculate, easy to fabricate, blade designs that will get you to (or above), say, 80% of the Betz limit for the turbine proper. It's impossible for ANY blade design to go above Betz. So a "perfectly efficient" blade would only get you another 25%. You could get more additional power by sticking with the simpler blade profile and increasing the blade length by 12%.
Similarly, extreme precision when constructing the blades is also not an issue. The blades just have to be strong enough to hold together, balanced well enough that you can finish that job with some counterweights, and kinda close to a decent profile. If it's a little off a good profile the main effect will be a minor reduction in efficiency. See above.
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