Amateur Aerodynamics

In the first chapter of Aerodynamics of Road Vehicles you will find, regardless of edition, an excellent overview of the history of passenger vehicle aerodynamics written by Wolf-Heinrich Hucho. In it is this chart,  showing the general trend of drag coefficients over time : This is from the most recent edition, published 2016. This gives us an idea of progress in reducing drag coefficients (at least in European cars, but I imagine a chart of American or Asian cars would show the same), which you can see sometimes moves in fits and starts before plateauing for a while. Generally , the trend over time is that drag coefficients get smaller, and it is assumed that cars become more efficient as a result. But is this really what’s happened? Sure, cars are more efficient now—but how much more efficient? And is all of that attributable to a decrease in drag coefficients? I found myself wondering this over the last several weeks as I’ve played around with various models simulating roa...

Weight is a problem for electric vehicles: almost invariably, EVs are heavier than their ICE counterparts of similar size. For example, the Chevrolet Blazer EV weighs 5163 lb in its lightest trim, 1245 lb more than the lightest ICE Blazer. Weight increases force and power required at speed, hinders maneuverability and negatively impacts driving dynamics, increases particulate matter pollution ( from both tires and brake pads ), and reduces efficiency —not to mention requiring greater energy inputs to construct commensurate with the greater mass of material needed to build the heavier car in the first place. This Hyundai Ioniq 6 weighs 1000 lb more than the Sonata, despite the two having similar dimensions. The reason EVs are heavy is because they require large batteries to have acceptable range; however, while total range increases with battery size, efficiency (range per unit of energy) goes down as more weight is added by the increased battery size, which requires more energy per u...