You’re absolutely correct. You’d be surprised at what a tiny little ridge can do. Sometimes it only takes 5 or 10 mm to trip the flow.

Yeah, unfortunately they’re the only way to get the air to break off the back of a rounded bluff body. They’ll probably get more pronounced as tine marches on.

Ha, thanks but don’t get too excited. It’s mostly making Power Point slides and parroting the laws of physics to managers. Everyone doubts ole Rock Bottom, but nobody would dare question Newton and Einstein!

Eh... more often than not they are guided by their own artistic idea of what the car should be. I mean, they’ll poll potential buyers at times, but if that were their sole source of artistic direction, I’m pretty sure the Lexus Predator Face or BMW Bangel Butt wouldn’t have ever seen the light of day!

I agree, I like a more “formal” wagon shape. However, I’m far from the target buyer, so my opinion is pretty meaningless! The only leg I have to stand on is based on physics! 

All true. I’m certainly not the target buyer for a luxury wagon, so my opinions are completely formed by aero performance and my own crankiness! I guess their wagons look neat-ish, but I really do prefer the looks of Audi sedans.

I would agree, were it not for the fact that some cars have looked great with square relatively back ends (like the Volvo V70, or first gen Explorer). You’ll find that the studio guys follow cycles of what they think is cool this year. Limp back glass angles and “the layered look” are two huge themes right now. It’ll…

Oh make no mistake, I’m an idiot too. I just happened to accidentally fall into a job that makes me sound like I know what’s going on ;)

This is 100% a studio-driven trend. These slack rear angles are terrible for aerodynamic drag and packaging. Upright back glass is good for reducing drag. This is all design studio. Artists trading fuel economy and usable space for “style”.

No. Slack backlight angles are terrible for aero. Upright back glass is good for aero. This is all design studio. Artists trading fuel economy for “style”.

I do love the Level 2 wheels...

Any profession where “just add more concrete” is a viable solution to a problem isn’t engineering.

To be fair, it’s a Performance Pack Level 1 with better looking grills (both upper and lower), unique wheels, different exhaust tips, different exhaust tuning (it really sounds pretty different), a little more power, a little higher Vmax governor, and it’ll hold it’s value better because “hur dur special edition”. If…

Volaré (whoa-oh)

I’ve spent a bunch of time in a BMW i3 and an eGolf and was impressed by how rarely I used the mechanical brakes.

Haha, that’s what I say! But in all seriousness, the studio likes to see light through the wheels. Any opening of the wheel is bad for aero drag due to it’s influence on underbody air flow.

Right, but brake cooling requirements are almost always driven by regulatory testing, not anticipated usage. High-performance cars can have brake cooling targets driven by some expected track performance, but that’s relatively rare in the normal automotive world. Like, GT350 rare.

You’re 100% right. Cooling drag is a huge contribution to total vehicle drag, which is why many car companies keep trying to add active grill shutters to everything. Block that damn cooling mess off as much as possible!

Government brake performance tests don’t let us rely on regenerative braking, only mechanical braking. That’s why the Nissan Leaf and Model S have such big brakes, even though they don’t use them all that often.

So as an actual aerodynamicist for an actual car company, I feel like I need to weigh in here. Closed wheels don’t do you any favors for brake cooling, and the studio designers hate them. That’s pretty much it. Nothing else to talk about.