The Citroen D-series

With the Citroën Traction Avant only four years old, the powers that be at Citroën in 1938, knew that eventually they would need a replacement for this ground breaking car. Work started on what was called the VGD project. Early drawings done by Traction Avant designer Flaminio Bertoni can be found back to this date.

When WW II broke out in Europe and France was occupied by the Germans, work on this project went into very guarded secrecy. Once the war was over in 1945, work on the project once again continued and would continue right up until the release of the Citroën DS in 1955.

When the Citroen DS was introduced to the world at the Paris motor show on October 6th 1955, the world was stunned. Many car magazines had predicted some ground breaking things to be introduced with this new vehicle, but nothing like this. 750 were ordered in the first hour of the show, and 12,000 were ordered by the end of the first day. People were amazed!

For the first time injection molded plastics were used in areas like the dash board and the engine fan. The dash board won an Italian design award in 1957 for being the largest piece of injection molded plastic used in mass production of the day.

The Citroën DS continued with front wheel drive that had been introduced with the Traction Avant, but that is where the similarities stopped. The DS had so many new and innovative features and systems, it is amazing they were able to fit them all on one car. Plus they kept most of them from the prying automotive press of the day until introduction.

To begin with, the Citroën DS had a unitized frame, often referred to as a punt frame, that all 12 exterior body panels were bolted to. Nothing had ever been done like this before. Not only that, but while other cars looked like bricks on four wheels, the Citroën DS was very aerodynamic. In fact, if you view it from overhead you can see it resembles a teardrop. This teardrop is tapered and rounded at the front, expanding gracefully to its widest point at the center or B pillar. It then tapers off gracefully to the rear. Even the underside of the Citroën DS is smooth, with no obstructions to catch the wind. The combined coefficient of drag and frontal area of the Citroën DS made it by far the slipperiest of its day.

The real crown jewel of the Citroën DS was it's light weight, high pressure, hydro pneumatic hydraulic system, designed by Paul Mages. Using technology from the airplane industry, the Citroën DS was able to operate the suspension, the brakes, the steering and even the shifting of the gearbox with hydraulics. Accumulators that were partially filled with nitrogen and separated by a membrane, with the other portion filled with hydraulic fluid, acted as amplifiers to aid the system in its operation. The Citroën hydraulic system was able to do all of these functions with a little less then 2 gallons of fluid. As a comparison... a typical garbage truck uses about 50 gallons of fluid to operate its ram without the use of accumulators.

Systems similar to the Citroën's are used on air craft carriers to operate elevators that bring planes up onto deck quickly and on helicopter gun ships to move their gun turret around swiftly.

All this technology on a car being built back in 1955! The same year many American cars were moving from poured or babit to shell bearing mains and connecting rods in their engines, and 12 volts for their electrical systems.

At the time the Citroën DS was introduced, its strange, almost alien looking, aerodynamics and multiple systems were far from the norm. Today aerodynamics, advanced hydraulics and electrical systems are the norm. Looks like Citroën was not so far off the mark after all. Citroen was simply ahead of its time.