General:

These little fins are inspired by the ‘fish fins’ developed by Toyota. They aid in maintaining laminar airflow, which improves the handling and stability of their vehicles. It may not seem like these little bits of plastic can have any effect on a large car, but that's exactly what Mike Sweers (an Executive Chief Engineer for Toyota) thought when he saw them too. A short read on the implementation of these is here https://www.popsci.com/technology/toyota-aero-stabilizing-fish-fins/. Another explanation for their impact on aerodynamics is the tubercle effect observed on whale fins. I may be an engineer, but my fluid dynamics knowledge is limited, and I would recommend the Wikipedia page for the topic if you want to get a good explanation and idea of how this is relevant (https://en.wikipedia.org/wiki/Tubercle_effect).

These models are incredibly simple and are in no way optimised. However, if anyone out there has any skill in fluid dynamics and can improve the design or identify ideal mounting locations on specific cars, then that's what open source is for. I was just fascinated when I learnt about these things and couldn't believe there wasn't more available information or use cases.

Printing:

Unfortunately, I don't have my Bamboo just yet, so there are no special print profiles for this one. However, both files are very simple, and I'm sure they will print fine with the basic material profiles. For the Long Fin, this was designed to be 310mm long, however if you don't want to print it on a complete diagonal to get the full length just scale it to 80%.

I would recommend printing these in ABS and utilising vapour smoothing to get a pristine finish that will help with aerodynamics.

Installation:

These can be fixed to the exterior of your car using double-sided automotive tape such as 3M Exterior Attachment Tape. 

As I said, these haven't been tested or optimised for mounting location. However, as their general idea is to help control and direct airflow, the general idea is to place them on large flat areas at the rear sides of the vehicle, similar to where they are shown on the GR Yaris and other Toyotas. For the small fins, an idea is to place 4 or 5 of them across the front edge of the bonnet to mimic the tubercles on a whale's fin and help maintain laminar flow over the bonnet and windshield. 

Future Improvements:

I plan on trying some fluid simulations on these to see if I can improve them and maybe putting them on a model of a common car to get some before-and-after data. I may also just print these when I get my Bamboo and do some before and after drives to see if I can feel a difference. I will update this when I have more to share.