The breaking glass during the unveiling of the Tesla Cybertruck wasn't the only shock: the exterior design completely breaks with the hyper-streamlined styling of the other Tesla models. As aerodynamics is the dominant factor for the range of electric vehicles, we wanted to find out what was playing.
Given the simple, boxy design, it didn't take long for 3D models to appear on the internet. We took one that looked good enough and uploaded it to AirShaper for a quick first analysis. Although the model wasn't the real one, we were looking at the results with big, curious eyes to spot anything that could counter our aerodynamic intuition on this block-shaped truck.
First things first - the side profile of the car. No curves, just straight lines. Vertical at the nose, inclined upward at the front half, gently inclined downward at the rear. There's clearly flow separation at the front, but that air is being pushed back onto the hood & front windshield shortly after. More surprising though, is the fact that there is hardly any separation at the sharp angle at the rooftop! Much depends on the local rounds they will apply at these edges (which may not be reflected properly in this model).
That means that there is quite a good pressure recovery: air is pushed away at the front, creating drag. But it contracts nicely at the second half of the roof, pushing down on the rear window. This pushes the car forward like a wedge, counteracting some of that force acting on the front.
But 2D slices through the centre don't show the full story: not all the air goes nicely on top of the roof. Rather, part of it curves around the A-pillar (the edge between front and side windshield) and then curves back up around the roofline to join the centre flow. This creates vortices which in turn create drag on the car.
Other than that, those large open wheel arches & fenders aren't doing the car any aerodynamic favours. Although they could be helpful in making the air jump across the rotating wheels (which generally act like air mixers), they generate quite a lot of drag of their own as well.
Based on this quick & dirty analysis, we obtained a drag coefficient Cd of 0.48 (download the full report here). More than double than the Cd of 0.23 for the Model 3, and perhaps not even impressive for a pickup truck. But again, this was just a quick & dirty analysis based on a public 3D model. Until we find a more detailed model, we're much looking forward to your comments - let the games begin!