The "Bionic" Boxfish

Car-makers have often looked to nature for inspiration when designing their latest, greatest creations, and considering how many superb natural examples there are of sleek, effortless motion it’s probably not all that surprising. It is a little surprising however, that in a world filled with streamlined sharks, penguins, dolphins and tunas, the designers at Mercedes-Benz took their inspiration from the charming but unlikely boxfish for their 2005 “Bionic” concept car.

Ostracion cubicus makes its home in the coral reefs, lagoons and seaweed of the tropics where it lingers near the seafloor to hunt for burrowing invertebrates. While its allegedly low-drag shape, excellent manoeuvrability and unusually stable design meant that shaping the car like a boxfish was supposed to make it aerodynamic, more recent research shows that the over-enthusiastic engineers might have been misled.

Scientists laser-scanned preserved specimens of the boxfish, and then created detailed computer models of its body to run through simulations. They also used 3D printing to make physical boxfish models, which they tested in a flow tank. What they found was that contrary to previously thought, the boxfish actually experiences more drag in the water than most fish, and that rather than being especially stable, it is especially prone to swerving. While this means that the boxfish is superbly equipped for quick evasive manoeuvers in the tight spaces of a coral reef, it makes it a less-than-ideal model for car makers, so it remains a mystery as to how the normally meticulous Mercedes got it so wrong...