It was the summer of 1982, the year saw Mercedes-Benz presenting the new C-Class – regarded as a ‘baby Merc’ because it was smaller than any existing model from Stuttgart. As customers raved about the new model, a team of Daimler-Benz research engineers were busy presenting a city car concept to the management. The concept vehicle had front-wheel-drive, two seats, sliding doors and large windows for an optimum all-round view.
Looking back now, was this the ancestor of the A-class? “Sure, the minicar is what stimulated us to think about new vehicle designs,” remembers Bernd Loper, project manager for the development of the A-class and one of the “founding fathers” of the innovative model which was caught by the camera of a spy photographer and led to speculations about a new model! The ‘breadbox’ design stumped the speculators who were puzzled about the tiny size and how it would be incorporated in the company’s line-up.
There were solid reasons why the original study never made it to large-scale production: the little car failed to satisfy the stringent Mercedes-Benz safety criteria which give top priority to passenger safety. To overcome these hurdles would take new ideas which weren’t around at that time and only materialised years later in the form of sandwich design. Nevertheless, that concept study did a valuable service in paving the way for an entirely new Mercedes compact model. As Loper says: “It helped to define aims for the planning of a Mercedes sub-compact car and put our efforts on the right track.”
This was the beginning of a process of several years’ research into a Mercedes sub-compact car, initially concentrating not just on technical aspects, but mainly on the wishes of the customer, traffic analyses and the findings of sociological studies. Mercedes market researchers spoke to more than 1,000 men and women motorists in Europe and asked them about their visions of the car of the future. This yielded a broad spectrum of opinions with various sets of demands:
– attractive design
– very compact exterior dimensions
– spacious interior
– high utility value
– high standard of all-round safety expected of a Mercedes
– low-emission engines with high fuel economy
– alternative propulsion systems
Traffic studies conducted in Greater Berlin came to similar conclusions: the time was ripe for an innovative, extremely compact automobile taking up less space on the road, consuming less fuel and producing lower exhaust emissions. But the objectives and customer demands that had been defined could not possibly be met by a conventional sub-compact car design. Time for a rethink – there were still conflicts of aims which had to be overcome. Specifically, how to design a car with small exterior dimensions, but the interior space of a medium-size sedan? How should you design a car that is suitable for different propulsion systems? How can the company’s stringent internal safety regulations be met with a small bodyshell? In other words: new ideas were needed – ideas that would point the way for an entirely new class of car.
The sandwich design arrives
All the criteria were collated in a matrix and evaluated. A new design was on the table for a conventional front-wheel drive system with the novel principle of a drive unit accommodated in a sloping position, partly in front of, partly underneath the passenger cell so that in a crash it can dip downwards, thus not presenting a danger to the car occupants. Since the bodyshell is divided into two horizontal levels, this invention was called the ‘sandwich design’.
As Loper says, “The conclusion was obvious: to have extremely compact dimensions and still achieve outstanding variability, spaciousness and safety you need to make sub-compact cars higher. In our points assessment, this principle beat the conventional car design in almost all disciplines.”
Not surprising: in contrast to a conventional design in which the passenger cell sits in a low-set pan with structural members at the front and rear, the sandwich design has members going straight through from the bumper to the tail. The passengers are positioned above the member construction and are thus protected against impact. This offers particular advantages in a crash – while conventional body systems have to employ special structural member designs to conduct the impact forces around the passenger cell, this complex “bypassing” of the passengers is no longer necessary in the A-class. The straight longitudinal members absorb the forces of the crash in a single plane below the passenger cell, converting them at a high level of efficiency.
Birth of the project
The invention of the sandwich design then provided the impetus in November 1991 for the implementation of a second project in the form of a basic study. Loper can still clearly remember the day the decision was made: “28th November, 8:00 o’clock a.m. – that was the birth of Study A, the direct predecessor to the A-class”. Two driveable prototypes were to be built – one electric-powered, one with internal combustion engine. The Mercedes board aimed to present them to the public at the 1993 the Frankfurt International Motorshow so the time-frame for development was less than 24 months.
But then came a different turn of events. At the presentation of the design in June 1992, the managers in Stuttgart already decided to set a course for large-scale production. A work team began recording all criteria for a possible production model in skeleton specifications. “That was a really unusual approach,” says Alfred Kist, head of A-class development, “because normally you would have first had a pre-development phase of roughly two years. But we were so enthusiastic and so convinced by the car and its design that we went all out right from the start”.
From then on the process proceeded on two levels: a pre-development and design team took care of the studies for the motor show while, from January 1993, a project team began the development of the production model which is today called the A-class.
Strong, positive public reaction
Study A’s reception in Frankfurt, where it was presented as an experimental forerunner and idea-testing model for the A-class, vindicated the company’s decision to offer a compact car. The reaction of the press and the public was overwhelming. Some 1,800 newspaper articles with a total circulation of 930 million were published about Study A, making it the undisputed star of the Frankfurt Motorshow.
Visitors to the motorshow were also thrilled. In response to the question whether Mercedes-Benz should build this car, 90% of visitor answered yes, because a car in this class with all the qualities which go with the name Mercedes-Benz would provide customers with something they had been looking for for years. In Japan where the Mercedes study was the major crowd-puller at the Tokyo Motorshow a few weeks later, 95% of those questioned said they would like to see the innovative model going into production soon.
Customer opinion was also constantly the focus of attention during the A-class development phase. Regular customer interviews yielded new points and suggestions to be taken into consideration. Taking into account the wishes of young families, for instance, Mercedes engineers lengthened the new model’s bodyshell to 3.57 metres (Study A was 3.35 m) primarily leading to an enlargement of the boot. The result: even when the back seats are occupied, the rear compartment of the A-class offers sufficient space to easily stow a pram.
With no doubt about the good market prospects for a Mercedes model in this size class, development was in full swing. This also meant that a production site would have to be found quickly – a plant with sufficient capacity for large-scale production of up to 200,000 cars per year.
“There was a choice of several sites in France, the United Kingdom and the Czech Republic, but the final decision went to the newly-built Mercedes plant in Rastatt, Germany. This was made possible by the site’s pioneering management – staff agreement to reduce costs and increase productivity”, remembers Ulrich Bruhnke, head of Car Development and manager of the A and C-class product groups.
Ten days before Christmas 1993, while negotiations were underway in Rastatt, the designers invited the board, directors and project managers to a presentation of five design models in the dome building at Sindelfingen. At the end of the event, which was held under the motto “One will be the winner“, the A-class interior and exterior design had been decided. The development team could now really get stuck into the task of adapting the systems and equipment to the new model which was already due to roll off the production line 32 months later. An ambitious target, given that the engineers had almost twice as many jobs to solve than is usual when developing a new car.
“Almost every new car is based on a predecessor model,” explains Bruhnke. “Many parts are kept the same or just slightly modified. But with the A-class everything was new – from the engine to the tailgate.”
One major milestone in the development was definitely passed in optimising the safety of the new body design. This also saw pioneering work. Never before had a car as short as 3.57 metres had to meet such high safety standards, and no manufacturer had ever attempted to use a novel body design to compensate for the physical crash handicap which cars of this size have. Computer simulations had pointed the way for the engineers, a large number of crash tests helped in the fine tuning and finally proved the wisdom of this new development with all its future potential.
From April 1995, the first prototypes were up and running and set off for testing in the field throughout the world. The engineers had already tested the new model’s systems on so-called component carriers which were similar in appearance to the Study A. A major prototype test was scheduled for September 7th 1995: the A-class versus E-class crash test. “We wanted to use this vehicle-to-vehicle crash to test passenger safety in a typical accident involving oncoming traffic and the E-class’s crash compatibility in a collision with a smaller car,” explains Thomas Merker, strategic project manager for the A-class. “Mercedes-Benz had never carried out such a test on a new model in its prototype stage before.”
And what was the result? “The sandwich design fulfilled all our expectations. Of course there were still a few minor problems in 1995, but these were solved within a short time.” A second vehicle-to-vehicle crash in which an A-class and an E-class collided in summer 1996 confirmed once more the outstanding passenger protection of the Mercedes sub-compact model.
A total of 64 prototypes were out and about throughout the world covering millions of test kilometres between April 1995 and the start of pre-production in summer 1996. As Bernd Loper says: “The 32 months development time were definitely hectic. But they achieved a great deal – for Daimler-Benz and, in our opinion, for automobile engineering as a whole.”