I've been attempting to print this successfully for months. I've had many attempts that turned out the way the one at the top of this page did. My observation is that the smaller wing is flexible enough that when and if the nozzle tip hits it, it deflects giving you both the strings and potential offset. So, one way to improve the print is to stiffen the parts by adding infill. Another is to create more retraction of your nozzle when going from one wing to the other so it doesn't hit it.
Valcrow, which direction was this turbine designed to rotate? When looking down from the top, mine have rotated both clockwise and counterclockwise. But, mostly, they don't turn at all when placed outside in the wind. I was able to get one spinning with a fan, but not outdoors. Have you ever tried yours outside in the wind? What speed of wind should start it spinning and in which direction. How much does balance have to do with its ability to rotate? Do you have any suggestions on how to get it spinning in the wind?
With zero infill, this design is very fragile. I've broken quite a few pieces when I've dropped them. Also, the blades have blown off the stand during a gust of wind. I lengthened the connector shaft so that it extends through both bearings in order to increase its vertical stiffness.
