If you don't know what SketchUp is, it is a great easy-to-use 3D modeling software. I am using SketchUp Make, it's free and it's great. So to begin, download and install it. If you already have it, open it up and read on.
In the first few steps I will go over the tools and how to use them. If you know how to use them already, jump right ahead. And if your just starting out, don't run away just yet, I promise it's not hard, in fact it only took me a few weeks to learn.
Step 1: Learn the Tools
The Image above is the toolbar. If you are on SketchUp right now, you have probably noticed that there are more tools than shown above, the ones not shown we won't be needing. From left to right you have: The mouse tool, Eraser Tool, Draw Tool, Arc Tool, Rectangle/ Circle/ Polygon/ Rotated Rectangle tool, Push/ Pull Tool, Offset Tool, Move Tool, Rotate Tool, Scale Tool, Tape Measure Tool, Paint Bucket Tool, Orbit Tool, Pan Tool, Zoom Tool, And Zoom Extents Tool.
I will be explaining the tools in later steps.
Step 2: Make the Base
To begin make sure you are using the feet and inches template. Next, use The Rectangle Tool to make about a 266' x 57' Rectangle, Exact measurements are hard to get, so don't worry. Unless You are planning on printing it, the measurements will not matter. If you are though, I recommend that you scale it down a lot, Because if you do, the fan WILL be usable.
After that use The Push/Pull Tool to give it depth (about 1'). It should look similar to the image above.
Step 3: Shape It Up
Let me start this step by saying you CAN delete lines so don't get worried when I tell you to make a bunch of lines, it will all be cleaned up at the end.
Start by putting a line down the middle in both orientations. It will automatically jump to the center when your close (there will be a light blue dot). I will be calling these spaces cells
After that, put lines going long ways in the middles of the two upper cells, use the Push/Pull Tool and push the two small outer cells through when you have reached the bottom they will automatically delete.
Delete the long-ways line from both the top and bottom of the base, keep the smaller and bigger part separated.
It Should look like the image Above.
Step 4: Curves and All It's Edges
Next, draw a line going through the center of the larger half (Short-ways).
Use the Arc Tool and click on the edge of the line you just made and then click on the edge where the short half and long half meet, repeat on the opposite side.
Push/Pull through until it is gone. And delete the line in the middle.
At this point you are probably thinking that it looks incorrectly sized, we will fix that toward the end.
It should look like the image above. Minus the line.
Step 5: Customize It
Use the draw tool to make different designs and patterns in the bigger half. Play around with some of the other shapes and such to get a feel for them.
Mine is shown above.
Step 6: Make Things Right
After you have completed your designs, it is time to make it a normal size.
Push pull the outer faces on the short ends to make it the appropriate size.
After that, use the drop-down button next to the rectangle to select the circle. Make a small circle at the middle of the bottom of the larger half. Don't forget to push pull to match the depth.
Then use the offset tool to make a very small circle in the center of it.
Next, draw 2 lines from the outer edges of the circle to where you like it on the outer edges of the larger half
It should look like the image above.
Step 7: Finish It Off
Next, use The Mouse Tool to highlight the whole thing. Left click and click on soften edges. Use the slider to adjust how smooth they are.
Press Ctrl+C to copy it. then paste it and highlight that and move it on top of the first one repeat that about 9 times. When you get to the 10th, do the same thing, but before putting it on top use the rotate tool to flip it face down then put it on top. It is not exactly an easy task so be prepared.
Be sure that they are lined up.
Make a piece to go through the small hole you already made, make sure that the "blades" can not get off of it.
It should look like the image above.