Maybe one way to get to a quick start with tweaking a parametric 3d
printable design from Thingiverse or somewhere else. There's quite many
impellers.
For example this one is parametric:
http://www.thingiverse.com/thing:259773/#files
Extremely easy to start hacking in Openscad, which is free software.
I attached a picture.
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valtteri.maja@xxxxxxxxx
Helsinki, Finland
Attachment:
openscad_tweak.png
Description: PNG image
