The general idea for a stackable wind funnel is that it is able to concentrate windflow to a smaller area, thus reducing the required blade size of any turbine that would want to generate power from it. One nice thing about a stackable design is that you can continually add more wind funnels to the stack, increasing the wind gathering surface area. Intuatively, this could increase the power generated by the turbine (this claim is yet to be tested scientifically).

This design is for a vertical stack, with wind being concentrated at the top or bottom of the stack. (depending on the orientation). I prefer the orientation where the concentration goes toward the top. I like to think that this configuration can take advantage of any rising warm air that is produced by the enclosed structure. Perhaps it is able to produce power with no wind on a bright sunny day.

Designer's Side Comment: I've been working on this for a while now. I think it's finally at a stage where it can easily be printed and assembled. The main limiting factor for this design is the build envelope - which is why it needs to be broken up and printed in parts. The new Replicator should be able to print the full fin without too much trouble (negating the need to tape together the frontfin and backfin models). The parts shown in the photos were printed on a Thing-O-Matic and an Up!(PP3DP).

Update 2012 Jan 16: Modified mousears on Core Wall; a lot more base surface area on the platform to keep it secure.

Parts:

A) Front_Fin (tape to back_fin) B) Back_Fin (tape to front_fin) C) Fullfin (print whole if you have a big enough build area - this is the big part that parts A and B were broken from.) D) Core_Wall E) Slope

There are 'mouseared' and non 'mouseared' STL exports from the .scad file. Please see the .scad file for further customisation.

Steps:

1. Print 18 of each for enough parts to create 1 stackable wind funnel.

2. 2.1) As of 9 Jan 2012, there are built-in tabs for some parts to slide in together. 2.2) There are no built-in mechanical connectors for the front and back fin. They need to be taped or glued together. 2.3) Ideally, it should be printed as a single part, but not all consumer level 3d printers have enough of a build area to do it all in a single hit. If you have such a printer available, use "trimmed_fin(0)" to render a complete part.

3. Add further rigidity with superglue or gapfiller

4. Produce as many wind funnels as desired!!