I've always admired how Hugh Piggott could present sometimes very technical information in very tangible terms. I'm not trying to contradict norms for defining accepted terms. What I was saying is that some of the spreadsheets that are available appear to me to have fields that are intended to help with the layout, and material to be removed when carving blades. Alpha is the angle between the the chord line and the direction of relative air movement, but the chord line is not always the same as the flat of the blade. And, if you are carving blades it is good to know which you have.
There is also a point as you move toward hub where the chord width becomes very wide at the root, and the angle very "coarse", as Hugh describes it. At a certain point it becomes impractical, and you must choose some compromise between the theoretical results and what is practical for the material and properties of the blades. So, with Hugh's calculator for example, there's a point where you are entering the actual wood width, and the drop at those station is calculated using this width.
I had to remind myself what the flow angle, phi is... but I can see now it is the angle between the relative wind and the rotor plane, alpha + beta. It's interesting that in in looking this up, I found where beta is sometimes referred to as "setting angle", or simply "pitch", so nomenclature does vary some.