0.146 - Page 3 - Fuel Economy, Hypermiling, EcoModding News and Forum

freebeard · 06-02-2020, 12:19 AM

All these 0.20-1 cars have the top-side sorted. Maybe the aerodynamic gains aren't in the back half but in the bottom half?

edit:

Quote:

Originally Posted by Batman Jr

I liked it from the first glimpse of duct tape in one of the wind tunnel shots.

For me it was at https://youtu.be/KNPdPOTTTWk?t=7 in the 2nd video, with the ornithopter windmill.

JulianEdgar · 06-02-2020, 01:23 AM

Quote:

Originally Posted by Fat Charlie

It's hard to make fake claims about a shape you intend to produce. At least, if you don't want the inevitable backlash to overshadow what you actually did accomplish.

I'm a fan.

Actually I understand that a *lot* of cars don't match their claimed Cd values when tested in other manufacturer's wind tunnels. If it ever gets to production (doubtful), this one will likely be the same.

serialk11r · 06-02-2020, 01:59 AM

I vaguely recall reading about independent tests when MB released the CLA (claimed 0.22), and it seemed like their numbers were something like 10% lower than what the wind tunnel showed.

That means someone has a measurement issue because driving the car in still air is going to produce a consistent amount of drag. However it seems like it would definitely be within 15%.

I can easily believe 0.16 (that's adding 10%) being possible with that shape. The XL1 is 0.159 without a full tail as well. Mercedes has gotten their minivans close to a Prius in Cd, so maybe there's a way to manage the drag there more effectively than most other OEMs have done.

Sending air under, instead of down the sides of the cars where the wheels will interfere is probably very useful. The Alfa Romeo BAT concept had (probably) poorer management of airflow around the tires, but with a bit more tail it got below 0.2.