The drag and lift equation
The figure was confirmed in the FKFS wind tunnels in Stuttgart, Germany, under the conditions of the Worldwide Harmonized Light Vehicle Test Procedure (WLTP). By comparison, a Jeep JL Wrangle has a drag coefficient of 0.454. In the realm of more modern sports cars, the Lexus LFA (with wing retracted) has a Cd of 0.31.
Sports cars are not always as aerodynamic as one might imagine because of the downforce they are trying to generate. However, even more modern EVs have yet to drop below 0.2, such as the original Tesla Model S achieving 0.24, the Model 3 0.23 or the Lucid Air 0.21. The Lightyear 0 is almost as aerodynamic as the Mercedes EQXX concept car, which has a Cd of 0.170.
As this car has proven, reducing drag is hugely important to increasing the efficiency of electric vehicles, whose range often suffers over long distances on the highway. Keeping drag low while controlling lift is a very important and difficult balance to maintain. “We are very proud of this incredible achievement”said Arjo van der Ham, the automaker’s chief technology officer. “We had to start from a blank sheet of paper when we first started developing our technology, and with great commitment and hard work, we continue to push the boundaries with every step like this.”
This low drag coefficient, combined with the Lightyear 0’s solar panels, allows the car to claim a WLTP range of 625 kilometers. Under optimal conditions, however, the car is said to be able to regain up to 70 km of range per day thanks to the sun. This means, according to Lightyear, that in a bright location, in circumstances where the car is mainly used for the average European commute, the 0 can last for several months before needing to be connected to a charger. All this efficiency and solar power doesn’t come cheap, though. The Lightyear 0, which goes into production in two months, starts at a price of €250,000…
The quest for the best Cx, a long story
The pursuit of the lowest possible move is not new. From the beginning of the car, aerodynamic research was undertaken, in experimental mode, with the first record cars such as the never satisfied or the amazing Alfa Romeo 40/60 HP with bodies by Castagna in the shape of an airplane. The first “production” car with a highly aerodynamic profile was the Rumpler Tropfenwagen, marketed between 1921 and 1925 in one hundred copies, which Volkswagen tested in 1979 in its wind tunnel and achieved a coefficient of 0.28, which the manufacturer would first achieve with 1988. Passat.
Afterwards, Crises are factors of technical progress. During the Great Depression of the 1930s, American manufacturers led the way with the Streamline style, embodied by the Chrysler Airflow. In Europe, Skoda with the 932 prototype or Horch and DKW in the early 30s are forerunners, but the streamlined fashion really explodes from 1934 with the sensational Tatra T77 developed by Hans Ledwinka and engineer Paul Jaray, who used his experience in the design of Zeppelins. The avant-garde streamlined profile of the Tatra launched a fashion that was even picked up and partly copied by Ferdinand Porsche for his Beetle.
It was then in the 1970s that aerodynamic research experienced a new leap forward, in connection with the oil shocks that encourages manufacturers to reduce vehicle consumption. This requires new limitations on the engines, but also more advanced aerodynamic research, also facilitated by the advent of computerized design. Citroën’s CX embodies this new trend perfectly. In 1982, Audi set a new record of 0.30 with the Audi 100, whose details were pushed to the maximum, such as windows flush with the bodywork. But two years later, the Renault 25 in TS finish sets a new mark at 0.28. The 90s did not see the coefficient improve significantly, but General Motors’ EV1, an electric two-seater produced between 1996 and 1999, set the benchmark at 0.19
In recent times, Mercedes has led the way with the electric sedan EQS, which held the record of 0.20 before the advent of the Lightyear 0. The Mercedes EQXX concept car, which recently passed the 1000 km mark on a single charge, remains ahead of the Dutch sedan by 1.70 but is not yet in production.