The last time we retraced the evolution of car body design, we highlighted Bugatti’s Type 32 ‘Tank’, designed especially for the French Grand Prix of 1923. We mused that it was perhaps the first car to have all four of its wheels enclosed within its sides.

Naturally it caused a popular sensation – yet there was another car introduced in the very same race that attracted even more of Autocar’s attention: the Avions Voisin Type C6 Laboratoire.

It was a world away from other cars of its era, and today it appears like something from 1927’s groundbreaking sci-fi film Metropolis or some retro imagining in ‘steampunk’ style (à la Spyker).

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“While most racing car designers have endeavoured to approach airship lines – blunt end forward and long, tapering tail – the [C6] may be described as having the profile of an aeroplane wing,” we reported back in 1923.

Indeed, Gabriel Voisin was a famous aeronautical engineer: in 1907, he had become the first European to build an aeroplane that could fly for more than a minute, out of the world’s first commercial aircraft factory, which had then provided weaponry for the French Air Force in the Great War.

This proved such a spiritual burden on him that he decided to switch to designing cars instead.

We continued about the C6: “The undersurface is absolutely flat and brought as near to the road as possible, and the upper surface has a considerable camber.

The entering edge is brought to a point, the radiator projects slightly above the upper surface, the engine projects even less, the driver and mechanic continue the line of the wing, the petrol tank is behind them in the greatest section of the wing, and the trailing edge is brought down to a point.

“By reducing the track at the rear to [about 75cm], the two rear wheels are recessed with the body of the car, and the rear axle, springs and shock absorbers are entirely inside.

“Not only is the design original, but the entire construction of the car is a break-away from the usual practice. There are no chassis frame members; instead, the body is built up in the manner of an aeroplane fuselage of wood, steel members, steel tubes and sheet aluminium for panelling.”

This meant it was of monocoque construction, which wouldn’t be common for decades to come, and weighed just 660kg – considerably less than the competition.

The spinning blades at the front, by the way, are not a propeller but a generator to power the cooling system.

Sadly, like most innovative machinery, the C6 floundered on debut: the four cars racing at Tours proved fragile and just one lasted all 497 miles, incidentally driven by co-designer André Lefèbvre.

Voisin wouldn’t go racing again, but the firm continued to innovate with its road cars.

In 1925, Autocar road tested the sporty 4.0-litre C5, saying: “It has all that unusual sturdiness which is so great a characteristic of the really thoroughbred car.

The driver can settle down at once to handle the car with the certain knowledge that it will do exactly what he wants. The [unconventional Knight sleeve-valve engine] has ample power.

The car’s stiffness is of great value when cornering, the car being practically without roll.

The steering is light and direct, and credit is due also to the very well-arranged suspension system.”

Into the 1930s, Voisin went for the trendy new art-deco style in a big way, crafting the likes of the stunning C25 Aérodyne (with its line of four circular skylights), the menacingly squat C20 Mylord (ideal for a Halloween creature) and the gracefully rounded C27 Aérosport (upholsteredin dizzying geometric patterns) for the ultra-wealthy.

Meanwhile, Autocar reported on Mr Voisin’s ideas to connect two straight sixes to make a straight 12 (which he called a ‘V12L’) and for a streamliner driven by a pair of wheels amidships and steered by single wheels at the front and back.

Being nationalised after World War II, Voisin never made another car – but its finest products today are worth millions and often win the fanciest concours d’élégance.