They could probably be further refined to improve their performance, but this clearly proves that Shapeways can produce useful, out-of-the-box RC propellers that can withstand high RPM.
http://www.youtube.com/watch?v=6y4cQZOyQEA
I have a few more on the way, and even more in my shop, but these are the only ones that have been tested so far:
6x5.5 Folding Prop Blades: http://www.shapeways.com/model/837403/printedprop-fold-6x5-5 .html
6x3 Prop: http://www.shapeways.com/model/833139/printedprop-fixed-6x3. html
6x4 Prop: http://www.shapeways.com/model/833143/printedprop-fixed-6x4. html
6x6 Prop: http://www.shapeways.com/model/831453/printedprop-fixed-6x6. html
(For reference, folding prop hub: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idP roduct=13129 )]]>