[NeilBlanchard]

Originally Posted by paconassa

Large back opening is a BS excuse from GM and here's why: Mercedes Bionic - 0.19 Cd



https://en.wikipedia.org/wiki/Mercedes-Benz_Bionic

And 0.19 is BAD, because the box fish, in which it was based, has a 0.04 Cd (!!!)

Your first statement is correct - except that 0.19 probably doesn't include the side view mirrors.

But a Cd of 0.19 is excellent. The Boxfish is what I modeled my CarBEN design on, so I am very familiar with the design. The blue model:



has a Cd of 0.095 (as far as I can find). And the earliest model of the boxfish had a Cd of 0.06 - seen at the back:


By Ryan Somma - originally posted to Flickr as Mercedes-Benz bionic car, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4498798

The hardest part of car aerodynamics - is dealing with the wheels on the ground. So, you need to realize what an achievement anything around 0.20 or less is.