1923. A war child: the Voisin C6 Laboratoire

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

Gabriel Voisin made his name and fortune building airplanes during World War I. These were highly innovative planes, being built entirely in aluminum, and not with canvas for the wings and fuselage like others of the time. Keen to exploit his experience with light alloys, after the war, Voisin was drawn to the automobile market. There he found a tough rival in Ettore Bugatti, whose splendid cars boasted performance levels that more than matched their esthetic appeal.

Surprising in technical solutions that combine a heightened search for aerodynamic effectiveness at the rear leaving the front-mounted engine uncovered and clearly visible

So, what greater challenge could there be for Voisin than to take on his already famous rival in a Gran Prix race? We are talking about the 1923 Gran Prix of Tours. Knowing that Bugatti was getting ready to unveil a car that would be revolutionary, both in content and style, Voisin responded in kind. He built an aluminum monocoque chassis with a closed and completely flat bottom — in Formula 1 racing, this idea finally came to fruition half a century later — and a long, tapered tail for greater aerodynamic efficiency. In line with the principle that cars should be teardrop shaped, the rear track was narrower than the front, and the wheels were flush with the body and had perfectly smooth rims.

The design in the plan clearly shows how much narrower the rear carriageway is than the front one. The body’s tight-wire wheels allowed the choice not to use the differential on the rear

The simple, modern lines of the tail were in complete contrast with the extravagant front, where the absence of fairing left the car’s overhanging 6-cylinder inline engine, actually not that powerful (just 80HP), exposed. One great feature is the air-driven propeller, rather like a child’s windmill, designed to power the radiator water cooling pump. This car was ingenious, lightweight (just 660 kg), and fragile: of the four that were entered, three broke down and had to pull out. The only car that finished took fifth place.

A decidedly tormented front design: in addition to the largely exposed engine, you can see the complexity of the front suspension and the curious small propeller with a completely unexpected purpose

But the brilliant Voisin was not disheartened: he continued to create futuristic aerodynamic cars until 1938, although he was thwarted somewhat by his insistence on using engines with moving sleeves and no valves, which were less efficient than those with springs and valves.

To limit the amount of power drained from the engine, the engine cooling pump is operated by the propeller that rotates when the car is in motion