Hi everyone!

I thought I would share this project I did recently regarding the aerodynamics of the S30 with you.
A while back I came across some wind tunnel test data from the HybridZ community, and saw that apparently adding a rear ducktail not only reduces lift, it also appears to reduce aerodynamic drag! This puzzled me and I wanted to see why that might be. Since I could not find any good sources about this subject for the S30, I made a complete aerodynamic analysis of the car with and without a ducktail, mirroring the findings from the wind tunnel tests. I thought you might find the results interesting so I am sharing it with all of you here.

In short, the ducktail reduces drag by reducing the vortex (spinning air) generation over the rear hatch. The ducktail forces air to separate violently rather than following the bodywork, creating a much smoother rear wake.

You can read more about the project in detail at my website:
https://bkgraversen.dk/cfdproject
Let me know if you find it interesting and/or have any questions :).

/Bertram 

Interesting stuff! What about adding a front air dam? Both with and without the duck tail.