Why Do Hatchbacks Have Rear Wipers?

[DiHarley]

Hatchbacks have rear wipers because their rear design is vertically straight, causing the airflow from the sides of the car to swirl there, creating vortices. This leads to the accumulation of rainwater and debris on the rear window, necessitating the use of a wiper. Hatchbacks are typically of the hatchback type, where the rear glass and the rear door are integrated. The wiper's pivot is installed on the metal body of the rear door below the glass, so when the rear door is opened, it does not interfere with the wiper. The moving body of the car generates significant shear forces due to friction, and these sheared airflows are released at the rear, creating turbulence. As some of the air moves with the vehicle, there is a shortage of air at the rear, forming a low-pressure zone. When driving on dirty roads, the dust or mud kicked up by the rear wheels accumulates in this low-pressure zone at the rear due to the difference in air pressure. This is why the rear of the car is often the dirtiest after a long trip, making the wiper essential for cleaning the rear windshield and ensuring driving safety.