i did some updating on the "how to build a cyclone" wiki page. the page now has the except from Reed's Handbook (excerpting Perry) on cyclone dimension ratios, the calculator and instructions for making the difficult taper section, and CAD files for the base 5" gek cyclone if you just want to copy a ready to go one.
the wiki page walks through the making of the 5" cyclone as used in the gek v2.x.
here's some samples of the images over there.
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