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Yeah I did clarify it's not the worst, it's a smooth vehicle but it's got pretty bad turbulence at the rear due to that flat back, so it's no aerodynamic master

Yeah I did clarify it's not the worst, it's a smooth vehicle but it's got pretty bad turbulence at the rear due to that flat back, so it's no aerodynamic masterpiece. I only use that comparison because it's a bog-standard car and can't get anywhere near 300mph, so it might surprise people to know it has better aerodynamics.

et2o 7y ago
Not sure what you mean... A Prius is actually one of the single best production cars around in terms of aerodynamics (Cd around 0.24). That stubby tail is actually done on purpose because it reduces drag, not increases it as you claim. A lot of aerodynamics are pretty counterintuitive. Look at the big table of drag coefficients here: https://en.m.wikipedia.org/wiki/Automobile_drag_coefficient https://en.m.wikipedia.org/wiki/Automobile_drag_coefficient For the Bugatti, they probably weren't going for an ultimate low drag coefficients. They need to make sure their giant engine is getting enough air, which leads to lower performing shapes. Related, they also will want a lot of downforce to make sure the car stays on the road at high speeds; to do this they build a relatively non-aerodynamic car.
- Phillipharryt 7y ago
  Ok I hate to do this, but you're wrong about the tail reducing drag instead of increasing it. The rear of the prius has a design feature to reduce the effect of the turbulent wake created by having a flat rear, but it still has a large vertical surface at the rear creating a lot of wake. You can clearly see this in a wind tunnel. https://www.youtube.com/watch?v=Ov0iNPfs-WM https://www.youtube.com/watch?v=Ov0iNPfs-WM
  - et2o 7y ago
    Nope, do not believe so. The short tail with a vertical back is called the Kamm effect. It's a mix between having a practical design and minimizing drag. The numbers do not lie; there is a reason the Prius has an extremely low drag coefficient. Just think this through on a systems level. Obviously Toyota's engineers are not idiots and would use whatever aerodynamic effects they would since the entire point of the car is maximizing efficiency. If it was more efficient to have a different shape while still remaining a practical automobiu, it would. The entire design of the Prius revolves around this.
    - Phillipharryt 7y ago
      I'm not sure you're actually reading my message. A bluff at the rear of the car is terrible for aerodynamics, but having a rounded shape is inconvenient for the interior and storage. A compromise is made where you have a slope and then a bluff. The prius has this slope and then bluff. The flat surface is still bad for aerodynamics, it is not there to benefit them. Also stop just googling for wikipedia links then coming back with information you've only just learned. It's ok not to know everything.

et2o 7y ago

Not sure what you mean... A Prius is actually one of the single best production cars around in terms of aerodynamics (Cd around 0.24). That stubby tail is actually done on purpose because it reduces drag, not increases it as you claim. A lot of aerodynamics are pretty counterintuitive. Look at the big table of drag coefficients here: https://en.m.wikipedia.org/wiki/Automobile_drag_coefficient https://en.m.wikipedia.org/wiki/Automobile_drag_coefficient For the Bugatti, they probably weren't going for an ultimate low drag coefficients. They need to make sure their giant engine is getting enough air, which leads to lower performing shapes. Related, they also will want a lot of downforce to make sure the car stays on the road at high speeds; to do this they build a relatively non-aerodynamic car.

Phillipharryt 7y ago
Ok I hate to do this, but you're wrong about the tail reducing drag instead of increasing it. The rear of the prius has a design feature to reduce the effect of the turbulent wake created by having a flat rear, but it still has a large vertical surface at the rear creating a lot of wake. You can clearly see this in a wind tunnel. https://www.youtube.com/watch?v=Ov0iNPfs-WM https://www.youtube.com/watch?v=Ov0iNPfs-WM
- et2o 7y ago
  Nope, do not believe so. The short tail with a vertical back is called the Kamm effect. It's a mix between having a practical design and minimizing drag. The numbers do not lie; there is a reason the Prius has an extremely low drag coefficient. Just think this through on a systems level. Obviously Toyota's engineers are not idiots and would use whatever aerodynamic effects they would since the entire point of the car is maximizing efficiency. If it was more efficient to have a different shape while still remaining a practical automobiu, it would. The entire design of the Prius revolves around this.
  - Phillipharryt 7y ago
    I'm not sure you're actually reading my message. A bluff at the rear of the car is terrible for aerodynamics, but having a rounded shape is inconvenient for the interior and storage. A compromise is made where you have a slope and then a bluff. The prius has this slope and then bluff. The flat surface is still bad for aerodynamics, it is not there to benefit them. Also stop just googling for wikipedia links then coming back with information you've only just learned. It's ok not to know everything.