Teardrops and wind tunnels: A look at the world’s most aerodynamic cars

Inspired by VW's ARVW concept, we look at the cars with tiny drag coefficients.

Read the whole story

 

[Dr Gitlin]

But Cd is only part of aerodynamic drag - drag is actually proportional to CdA (i.e. Cd x A), where A is the frontal area. In other words, minimizing the frontal area is just as important as streamlining the shape.
https://en.wikipedia.org/wiki/Automobil ... #Drag_area

You know how I can tell you didn't finish reading this article?

 

[Dr Gitlin]

As a Model 3 owner, I've wondered why the aftermarket front and rear spoilers aren't the stock designs, especially if they can offer ~6% efficiency gains!

'cos chances are they don't? This sounds like the same kind of bunk that gets promoted as "fuel saving devices" for ICE vehicles. Nonsense like fuel line magnets, intake air vortex generators, blah blah. they rely heavily on confirmation bias. people install these devices, then subconsciously alter their driving style to be more "gentle" thus fooling themselves into believing the gadget is what improved their gas mileage.

believe me, if Tesla could eke out another 6% with some simple bolt-on devices, they'd be on every car they build. 6% is the kind of gain any car company would spend money to get. the vast majority of the time when any aftermarket bolt on device does make a noticeable difference, it's only in specific situations and often degrades things in other situations.

The link in that section of text goes to some CFD work that company did that shows those new spoilers should cut drag: https://unpluggedperformance.com/aerody ... a-model-3/

Although as both you,, yakinabe, and rosen380 point out, nothing is free, and it might mean an inability to clear parking ramps and speed bumps, plus a dangerously sharp edge on the lip of the rear spoiler.

 

[Dr Gitlin]

Wait, no mention of Tatra 77?

It was the first production car designed with aerodynamics in mind.

And while it's not clear whether 0.212 is the drag coefficient of the car itself or a 1:5 model, Tatra 77/77a and later models were pioneers or teardrop design.

It can be seen in Transatlantic Tunnel movie.

https://en.wikipedia.org/wiki/Tatra_77

Edit: added link

I left it out because of that very complication.

 

[Dr Gitlin]

Wait, no mention of Tatra 77?

It was the first production car designed with aerodynamics in mind.

And while it's not clear whether 0.212 is the drag coefficient of the car itself or a 1:5 model, Tatra 77/77a and later models were pioneers or teardrop design.

It can be seen in Transatlantic Tunnel movie.

https://en.wikipedia.org/wiki/Tatra_77

Edit: added link

I left it out because of that very complication.

Acknowledged. However, I would argue that the car should be on the list for several reasons:

a) it was a production car that pioneered both the aerodynamics and the particular design*
b) very few survived and testing the cd is a problem
c) despite it's meager power, it was quick and stable, which does point to advanced aerodynamics for its era

The 0.212 is probably unrealistic. "Tatra 87 had a drag coefficient of 0.36 as tested in the VW tunnel in 1979 as well as reading of 0.244 for a 1:5 model tested in 1941."

This could perhaps provide a clue.

Perhaps an article on history of aerodynamics in car design might be useful.

*Yes, Rumpler Tropfenwagen...

I did a brief history of downforce a couple of years ago, but I’ll put that on the list.

https://meincmagazine.com/cars/2018/09/ho ... eing-slow/