Gabriel Voisin gained his engineering experience in the infant aviation industry and was actually running an aeroplane factory in Paris before the Wright brothers’ planes were in production, producing a number of aircraft during World War I. He later switched to car manufacture and one of his best products was the V12 Simoun.
The Simoun was powered by a V12 sleeve-valve 4860cc engine which had many unique features. One interesting one was the electromagnetically engaged overdrive on all three speeds. Voisin claimed that his V12 engine could rotate at a constant 4000rpm due to the lightness of the reciprocating parts although he did provide the engine with a safety device which prevented seized sleeves from damaging the engine.
Two other cars which Voisin built in the 1930s were the Diane and the Sirocco, the latter a remarkably low-slung sports saloon with a larger V12 5830cc engine. The Simoun power unit was also available as an option in the Diane. The underslung chassis used on these vehicles had axles inverted above the springs which gave them a truly ground hugging appearance. Being cars of the Depression era, however, production was somewhat limited.
Early in his car building career Voisin gained a valuable lesson which has benefited many car marques over the years. The first car he manufactured used a chassis designed by young engineers from Panhard & Levassor. It was powered by a Knight engine. To get the car ready for test Voisin’s small team had worked through the night to finish the prototype. But when Voisin started the car and put it into gear, expecting to move forward he was surprised to see it moved backwards. In the haste to assemble the car the team of engineers had fitted the axle gearing the wrong way around!
Not to be daunted Voisin set off into the night driving in reverse onto the icy winter road surrounding the factory with only the rear wheel brakes to stop him. Surprisingly Voisin found that whenever he braked and expected to spin on the icy surface he stopped in a straight line every time.
He quickly concluded that a four-wheeled car should be braked on the front wheels! As soon as possible after this event he put into production one of the industry’s first four-wheel braked cars, with eighty per cent of the braking effort applied to the front wheels. Today many cars emulate his concept with front wheel discs at least.