There seems to be a neverending list of things that you can do with old hard drives.. This is a clycloturbine . (without the tail )
It is made from a piece of 2'' OD PVC tubing , and cost about $ 6.00 to make.. I got the idea from the windstuffnow site listed in my sig..
The trick to this one is to buy the coupler & end cap pieces because the coupler gives you a very good surface to hot glue to the HD spindle , i tried it before i had the coupler , and it wobbled a little bit , but with the coupler piece it wobbles not..the end cap is where i drilled & tapped a hole for for the HD Arm , which is a critical part of the whole mechinism..
For a size reference in pic 2 at the base is an old western digital 1170 HD ..
Comming out of the tube is two 10-32 Threaded rods 14 '' Dia. which is also the length of the two air foils..
the two rods support the wieght of the foils..
at the end of the rods are door hinges which i cut with my trusty dremmel if i had to do it again i would probably buy four more of the top two Home Depot hinges.. connected to the hinges are the wood air foils ..I carved these out of poplar , which btw is excellect wood for carving it has an extreamely tight grain.. the density was consistant , in any case, with no knots!!
i got the shape off one of the propeller sites..
this is a real fun project .. in the second pic the wind would be comming from the top of the pic..in the first pic the wind would be comming from the left , slightly ahead of the turbine..that is not a optical illusion , in pic one , that is really how it looks when the ' tail ' is pointing to the side like that .. if it was turned 180 degrees you would see the carving side of the foils..
the HD Arm is screwed into the top of the end cap, and then i drilled an offset of around 0.600 '' where the wood rods are connected which actually steer the foils as it turns ( when holding offset in one spot as the foils are spinning..)
the problem i am having right now is how to balance it , i suppose i could weigh each half , but when it really gets going , it still sort of wobbles a bit..
with the fan at low speed i get 124 RPM out of it , with a nice amount of torque..