Ideally, the races of the National Association for Stock Car Racing, better known as NASCAR for its acronym in English, are held on sunny days. There are times, however, when nature does not cooperate.
That is why the strict rules that govern NASCAR races require that the cars that compete in them have the electric motor and the necessary mechanism to operate a windshield wiper. However, if there is no forecast of rain on the day of the race, it is not mandatory to install the metal arm with the squeegee that sweeps the water from the windshield. No one would guess this possibility by looking at the NASCAR races of the last few years.
Beginning in 2017, some teams began racing with the wiper arm installed in a fixed vertical, or near-vertical, position in non-rainy races, something that now in 2022 is common practice in NASCAR. What is the reason? Apparently, the wiper arm in this position improves the car’s aerodynamics, to the point that some teams began to cover the arms with metal structures.
In 2018 there was talk of banning the practice. A NBC Sports report quotes Scott Miller, NASCAR’s senior vice president of competition, as saying on a radio show that “we generally allow them to run the wiper blade, rain or shine,” noting that this practice “is on our to-do list.” regulations for 2019, and we’ll tell you when you can and when you can’t run the wiper blade.”
That wasn’t exactly what happened. Four years later, NASCAR cars are still racing with the wiper arm in a vertical position, even covered in the vast majority of cases. The only thing the organization did was regulate the dimensions of the covers. Under the latest NASCAR rules, the canopy can be no more than 1.5 inches wide and 2.5 inches tall and cannot extend further than the windshield itself would extend at any point in its sweep.
No team has explained what the aerodynamic effectiveness of wiper arms in the hard position is, but the widespread practice indicates that it should exist, so as long as NASCAR continues to allow the practice, teams are obliged to adopt it to avoid falling behind.