Vertical Axis Turbine Raft

 

Finished result. (this is an adapted tetrahedron from drink cans) The cans are floating in the water in the cordial bottle, and rotate when the wind blows on the mylar sails. The cans are held together by the 3d printed parts found here, https://www.thingiverse.com/thing:5256279 , and the moving sculpture can be seen at https://www.youtube.com/watch?v=IAvNbqUQ8Mc 

Bolts used as ballast, there are bolts like this at the bottom of the red can.

Building mk1, these are the 3 330cc "sail" cans which are at the top. This was the first version of the sails, from lamination sleeve and gaffer tape.

The first version also included steel pins which were later swapped for lighter bamboo rods.

Jigging uses extra red joiners. The red parts need to be equispaced on the rims to make the tetrahedron. 1. Six parts on the rim are a neat fit, and with about 1mm between them they are equispaced. 2. Remove 3 jigs and glue with the hair elastic still in place. 3. Remove hair elastic when glue has dried.

Latest sails are mylar held on with clear office tape.

Net for tetrahedron

Second version. Despite changing the sails and pins, the water was still quite near the can rim of the lower can, and that called for....

a big red can!  I was prepared to buy one contents intact but found this one in the gutter. I bought the other skinny can but soon realised it didn't have enough floatation volume.

Second version floated too low still.

Woo hoo, third and final version in progress.

Hi

This shows my latest can raft, and I didn't need an expanse of water to test it! Pictures tell most of the story. It took 2 days to build, and the final piece in the puzzle was getting a 500cc high volume can which had enough capacity to float the thing. A cube or prt cube in the same pattern should work as well. Video is here, https://www.youtube.com/watch?v=IAvNbqUQ8Mc and the 3d printable file used to make it is here, https://www.thingiverse.com/thing:5256279  

Regards  Steve Nurse