The wind turbine is coming along a bit slower than I anticipated (not much new there - everything goes slower than I expect). That said, I built my tail today. I used 1/2" heavy guage tubing for the arm and 1x.125" angle iron to mount the fin to. I triangulated the arm to keep it rigid.
I have also been playing around with some dump load circuitry. I will probably model the previously mentioned controller since it is already made up. I just need to find all the components.
Now the really good news. I was talking to a buddy of mine who is a Tech Ed teacher the other day when he came in. I was showing him the turbine project and he was quite impressed. His school recently bought a 5x8' CNC router/mill. He said if I could draw the blades up in CAD he will cut them out for me! I am going to use solid laminated wood, just like most of the turbines here on otherpower.com. I haven't figured out if I am going to do one at a time or take advantage of the HUGE table and do all 3 out of the same block.
I am most in-tune to Autodesk AutoCAD, so that is the program I am using. I digitized some templates I found online and used them as chord stations along the blades. The source I found had a nice layout of different blade configurations for different size turbines so I took the set of templates that was closest to my machine size (unfortunately I didn't take note of the site - I just found it and used the templates hehehe).
Now - a BIG CAD question if anyone out there can answer it. I am using AutoCAD 2005. I have 3 chord stations - root, tip, and 75%R of rotor. I am also tapering the blades from a 12" chord at the root to 6" at the tip. Nothing fancy about the dimensions - that is just what I threw together. The question: How do I form a solid through the chord stations so that the blade comes out as ONE object with a uniform flow? I don't know if there is a command I can use that will allow me to select multiple shapes to extrude to/through - sort of like extruding along a path? I tried to do a 3D skin but I can only select a beginning shape and ending shape (2), and the skin doesn't fully conform to the shape of the airfoils selected at each chord station - it flattens it out (unless that is just AutoCAD's way of utilizing less processing power?). I tried to union the two (tip to 75% and 75% to root) skins and I got a message saying that I needed to select two or more solids.
Any ideas? I will play around with it tomorrow again and see if I can figure it out. I have never tried to do this before. I have extruded along paths before, but that was a uniform cross-sectional shape. Here I am dealing with 3 shapes AND a taper...
Steve
