Tesla Cybertruck aerodynamics simulation returns much worse drag coefficient than the Rivian R1T
Elon Musk promised a mid-2023 Cybertruck release during Tesla's quarterly results press conference the other day, as this year will be dedicated to ramping up production of its current electric vehicles which Tesla just can't make quickly enough to satisfy demand. The Cybertruck's controversial "edgy" stainless steel design hasn't dissuaded its fans from preordering for a revenue windfall that at one point surpassed the market cap of legacy carmakers like BMW before the electric pickup had even started shipping.
Said angular design has had the aerodynamics engineer from Numeric Systems, Aleix Lázaro Prat, wonder what would the drag coefficient (Cd) of the Cybertruck be and they went on to calculate it based on the publicly available geometry at the moment. The number that the software spat out was 0.39 drag coefficient, worse than the stellar 0.3 one that Rivian boasts about for its R1T electric pickup, yet likely better than the Cd of its other direct competitor, the Ford F-150 Lightning. According to Aleix Lázaro:
Contrary to what many people would think, the sharp edge of the roof does not produce a big detachment! It is true that the flow is not attached, but in fact the air follows down the slope quite seamlessly. The boundary layer does not substantially grow. This is quite remarkable and a big aerodynamic advantage compared to other pick-up trucks. Moreover, the diffuser makes a substantial effect in the center of the vehicle’s rear-end! It creates suction and reduces the wake...
On the other side, our results show clear turbulent structures created by the front edge which connects the bumper and the bonnet, the vertical edge right behind the front lights, the wheel arches’ “protectors”/surrounding edgy geometry, the rim styling and the geometry of the a-pillar and c-pillar. The generation of the turbulent structures is caused by the sharpness of these edges. These geometrical features increase the drag of the vehicle, which ultimately reduce the range the CYBERTRUCK. Furthermore, due to the sharp rear end, the flow instantly detaches and creates a considerably big low energy area (wake), mostly noticeable behind the top and side rear-end edges.
Mr. Prat offers the usual disclaimers that their calculations are based on the design available at the moment and does not account for future modifications of the Cybertruck that are likely to come about between now and the time the first preorders start getting delivered next summer.
All in all, while the Cybertruck's aerodynamics are twice worse than those of the Tesla Model S, making it lose battery range much faster at high speeds, its controversial design doesn't fare worse in that regard than the Cd of its direct competitors. With the exception of the excellent work of the Rivian team on the R1T truck which, however, offers more orthodox looks than Tesla's immediately recognizable Cybertruck.
Aleix Lázaro Prat, CFD Engineer, Numeric Systems GmbH (LinkedIn)