Dutch solar car company Lightyear says it has achieved a record score for aerodynamics for its 5-seater Lightyear One while undergoing wind tunnel tests in Turin, Italy.

It’s the holy grail of efficiency: aerodynamics have such a massive effect on how much power a car requires that Audi’s aerodynamics manager Moni Islam says it is more important that the actual weight of the vehicle.

The Lightyear One solar car, which was first unveiled in June, has been under development for two and a half years.

Lightyear’s mission is to address the desire for more range in electric cars, both by providing a source of energy in the form of solar panels built into the roof, and through light, aerodynamic design.

While the Lightyear One is not yet under production, at its launch Lightyear CEO Lex Hoefsloot promised that it would be “ultra-efficient”.

During several weeks of tweaking different configurations of the Lightyear One at the Turin facility, the Dutch carmaker scored a record 0.20 drag coefficient for the vehicle making it the most aerodynamic 5-seater car there is.

That’s a full 0.02 points under the 2019 Mercedes-Benz A-Class saloon which was named in 2018 the most aerodynamic production car on sale, and 0.03 points lower than the Tesla Model 3.

Developed by former members of Solar Team Eindhoven (the same team that won this year’s World Solar Racing Challenge cruiser class earlier in October), the Lightyear One draws on the Eindhoven legacy to deliver up to 800km range topped up through its on-roof solar panels.

To achieve the record efficiency, Lightyear’s team drastically altered the vehicle -with the record drag coefficient achieved thanks mainly to the the long, streamlined roof of the vehicle, as the shallow slope allows the air flow to remain attached to the roof surface.

The team also added wheel covers to reduce drag caused by the wheels turning, guiding the air around the vehicle.

The successful configuration of the test vehicle will require the carmaker to rethink the architecture of the vehicle but it is committed to delivering the optimum drag coefficient when it goes into production.

Hoefsloot said in a statement to the press that, “This significant improvement is only possible because we re-designed the car as we know it, radically starting from scratch and focussing on EV performance metrics that matter most for EV drivers: ample range and fast-charging speeds”.