Aerodynamics

The sober Dolphin

With the valuable support of Prof. Massimo Grandi's depth of knowledge and illustrative talent

Photo credit: Some images are taken from the book Asi Service "Quando le disegnava il vento" by Massimo Grandi

On 24 March 1936, the Autodrome de Montlhéry, near Paris, provided the setting for a rather unusual test. It involved a perfectly standard Ford V8 Type 68 carrying four people, and a rather strange vehicle, dubbed the Dolphin, created by André Dubonnet. Despite being built to be highly aerodynamic, this car, too, easily took four people. So, what exactly did the test consist of? Basically, it was an exercise designed to find out how much fuel a standard production car consumed compared with a car designed to guarantee maximum aerodynamic efficiency, over the same distance (194.477 km) and travelling at the same speed. Predictably, the Dolphin performed better in terms of aerodynamic efficiency, but the really surprising finding was that it consumed 38% less fuel, a remarkable difference.

Despite its (perfect) teardrop shape, the Dolphin, thanks to an ingenious Y-shaped frame and very forward-set driving seat, could accommodate four people

If this test had been meant to show that it was time to upgrade the aerodynamic efficiency of the standard production cars, then this result alone would have been enough. But instead, Dubonnet’s brilliant creation, based on an idea by Giuseppe Coda, ended up being yet another example of a fantastic prototype that remained a one-off. Indeed, the Dolphin was never put into production, although it did go on to inspire many stars of the “crazy” 1930s.

The Dolphin had very unusual lines. The rear wheels protrude from the tapered tail. The prominent rear fin is always clearly visible

What distinguished the car? Well, first of all it is worth recalling that Dubonnet was the wealthy heir of the homonymous liquor manufacturing company. This privileged background had made it easy for him to get involved in motorsports, driving Bugatti and Hispano Suiza cars. Passionate about racing and also engineering, he even patented an independent hydraulic suspension system that bears his name.

Based on an idea by Giuseppe Coda, the driver’s door and front passenger door are set into the front of the vehicle

What he really wanted to do was turn theory into practice: he designed a teardrop shaped car body and equipped it with a large, rear-mounted Ford V8 engine. The driving seat was positioned so far forwards that the door had to be set into the front of the car. The Dolphin was constructed on a highly original box frame, while the body incorporated wheel fairings, the rear ones protruding either side of the tapered tail. The prominent rear fin, evoking that of a dolphin, is the feature that gives the car its name. Remarkably, given its standard engine, the car had a top speed of 174 km/h.

This rear view highlights the quest for optimal aerodynamics and shows the car’s generously proportioned and unusual intakes, and the air vents for the rear-mounted Ford V8 engine