Voisin C6 Laboratoire History

For the 1923 Grand Prix de France at Tours, Gabriel Voisin applied his aircraft-manufacturing background to build a radical new racing car. The C6 Laboratoire was constructed as a full aluminum monocoque — no separate chassis frame — with a completely flat underbody and a long tapered tail inspired by an airplane wing. It is recognized as the world's first monocoque Grand Prix car, an idea that would not reach its full potential in Formula 1 until Colin Chapman's Lotus 25 in 1962.

The engine was a 1,984 cc six-cylinder sleeve-valve unit developing around 80 bhp at 4,800 rpm. A propeller mounted at the nose drove the cooling pump, eliminating a conventional water pump and saving weight — a quintessentially Voisin solution. Four cars were built for the season.

On the road the C6 was over-matched against more powerful competitors; the best result was a fifth-place finish by Lefebvre in the 1923 French Grand Prix. Voisin withdrew from racing after 1926 and returned exclusively to luxury road cars, but the Laboratoire's monocoque architecture stands as one of the most important structural innovations in racing history.