why do most hatchbacks have a rear wiper but coupes and sedans don’t

Question

The angle of the glass on hatch backs varies from straight up and down to almost horizontal. They almost all have a rear wiper.

sedans and coupes can have similar glass angles, yet don’t have rear wipers.

why?

In: Engineering

Answer 1

It’s not the angle of the glass, it’s the way the airflow whips around the back of the vehicle. Coupes and sedans are more aerodynamic, in that there’s no abrupt “end” to the shape of the car – they are pointier at the back end. So the airflow carries mist away with it. Hatchbacks and vans have an airflow pattern that whips the mist around, or creates a bit of a vacuum, so the mist settles on the rear windshield.