Darwin Wind Pipe

My initial version of a Darwin Wind Collector for a 4" PVC pipe sized so all the parts can be printed within the 200x200 limit of most printers. These can be used as air collector for enclosed spaces or as a way to drive a small wind generator (old PC fan) as shown in this video:
https://www.youtube.com/watch?v=Js8if1YmptU

Print count:
Collar: 1
Lid: 1
Wedge: 6

The section view shows the position of the fins vs the inside of the pipe and the profile drawing shows the dimensions of the fins themselves. This was produced with the inner fin profile.

Note: The only pipe specific dimension is the Inner Diameter of the Collar that needs to fit over the Outer Diameter of the pipe you are using so to use a 3" PVC pipe with 3.5" OD set your scale factor to 3.5/4.5 = .78 or 78%

UPDATE: I printed a version for 3" pvc (3.5in OD) by scaling each part by 78% the collar notches were too tight so I made a specific 3.5in version of the collar.

UPDATE 2: I've added two new lid designs