First of all, I am not much of a woodworker. I have experience making things out of wood, but I would not consider myself to be an "expert". I am not an expert fabricater either - I have a lot of machining experience (several classes related to manual and CNC machining), but I am not a fabriactor. I have some experience welding (I have a 110v wire feed machine). So this project from the start was not encompassing much of what I am an "expert" in. I do have the ability to come up with ideas and make those ideas come to life, so I put that to use and came out with a machine. No it isn't perfect, and no I didn't do a whole lot right with it. But guess what? It is my first wind turbine and I am happy that I had the opportunity to build it.
By the way, if you want to see what it looks like so far go here: http://s118.photobucket.com/albums/o117/KC8QVO/wind%20turbine/
WHEW! Now that all of that is out of the way:
I was thinking 4' blades, but I really think I need to make them even longer now. Going through the transmission (see the link above) I need a good bit of torq to get the thing to spin. I am thinking about 5' blades or so. I need torq. Speed is irrelevent, as long as the rotor spins over 110 RPM I'll be in good shape.
The generator is an Ametek 30vdc motor - HOWEVER: apparently it isn't the same motor that most people have used on here because it needs 1100rpm to produce 14vdc. That is the reason for the 1:10 transmission - to get the RPM's up from the rotor blade to the motor.
Steve