Automotive

I am sure this will put a smile on some faces 😉 Picture from: volvo850spiritclub ...  

Very true! On the surface, it presents a fact that is probably very surprising to most people because 99% of people probably don't know how aerodynamics work and how Cd is measured. Take for instance: tire width is a significant contributor of coefficient... 

The tire width will also impact the frontal area that you need to multiply with the Cw for the drag 😊👍🏻

The drag coefficient (Cd) number has to be multiplied by the cross-sectional area. The Volvo's Cd has to be multiplied by its (larger) cross-sectional area, whereas the sports car would seem to have a smaller cross-sectional area. Therefore, the boxy car ... 

The Volvos are a tad taller but also much narrower and have drastically narrower tires, which also impact the frontal area 👍🏻

Shouldn’t have assumed…

But as said above, the Volvos are narrower, if taller, so not so clear cut 👍🏻

The key stat is the the drag coefficient times the cross sectional area. Thats called the “drag area” That Volvo might have a Cd of 0.32 but its drag area is around 0.32 x 2.5 = 0.8 sqm The Countach has a Cd of 0.42 but due to a smaller cross section, it ... 

But many sports cars generate a lot of drag because next to the high Cw that they need for cooling and downforce, they are also very wide, so the frontal area is not that small, either 👍🏻

Marc

Marc

Here was the last major road trip with it: www.watchprosite.com

Doesn't corner quite as well though.....hmmmm

Thank you guys

All (4) of these were actually my dream cars as a kid. Yes yes (2) Italian sports cars and (2) Swedish station wagons I know.

"Wet" surface area (skin friction) and all surface joins and gaps, eg doors, window frames and moveable covers, will increase Cd.