If the shape with the least air-resistance is a raindrop 💧, why are most cars shaped like a backwards raindrop? 🚗

Question

I am basing my question off this [image](https://study.com/cimages/multimages/16/dragcoefficients8851096396303799158.png)

Edit: Okay, okay, I should have said “teardrop” instead of “raindrop.” Talking about the *actual* shape of raindrops doesn’t really help given the visuals I provided.

In: 558

Answer 1

It’s a good question, I don’t want to pull apart your question by citing requirements of commercial car manufacturers etc.

The backward teardrop shape is also very common in cars meant to break land speed records and arguably in things like F1 cars.

At those his speeds wind resistance is very significant. Which creates two competing goals. Of course the first is lowering wind resistance.

The second is actually being able to put down enough power to push through the air. At those speeds the air is very dense and restrictive. Without a downward acting force, the wheels will just spin in place. The wind resistance is greater than the tyre traction.

To overcome this, passing air also needs to push the car downwards onto the ground in a very significant way. This improved the tyres traction and allows for more power to be applied.

I assume the backward teardrop is meant to accomplish both goals, with the ramp like nose turning air impedance into a downward force. But take that with some salt, wind tunnels exist because the considerations are complex and simple explanations like this often don’t hold.

I think there is more to not using a teardrop design than this. To do with the action of turbulent air between the car and the road; but I can’t help with that.