Miguel Sánchez
MERCEDES C111 PHOTOS: DAIMLER-BENZ
One of the cars that has made the most stir in 2019 is the Peugeot e-Legend. There is no media -even generalist- that has not echoed this new prototype. Even the media specialized in classics have talked about it for its resemblance to the 504 Coupé. Presenting this model that will not reach series has been a good idea on the part of Peugeot. It was intended to announce the new technologies tested by the brand and, in sight, the e-Legend has been a good showcase.
But let's go back a few decades. Just as today many manufacturers are already investigating electric or autonomous driving, in 1969 Mercedes was also in full experimental phase. The German giant was seduced by rotary motors Wankel, the application of diesel to non-industrial vehicles and, of course, the incipient turbo.
The result of all this was an enormous technological effort from which many innovations applied to the series models would emerge. However, a car brand is not just engineering. It is also a company in need of benefits. In short, if you are testing with important technological innovations ... It is not a bad idea to publicize all that effort to position yourself as a reference within the sector.
But how to do it? Well, in the same way that Peugeot has done with the e-Legend. Presenting a prototype that leaves everyone with their mouths open. An object of desire to pique the interest of the public. After all, everything is invented. Even in the pretentious publishing industry… It is. The proof is that this same move was already made by Mercedes in 1969. It is now 50 years since the start of the C111 prototype saga.
C111. AN ICONIC PROTOTYPE THAT PROLOGATED THE SEVENTY
The truth is that it is striking how much some prototypes are remembered. Cars that most of the time we have only been able to see in photographs and that, of course, no one has driven except for a few professionals or a select few. However, they fuel the passion of motor fans like no other. One of these cases is the Mercedes C111. Without a doubt one of the greatest icons of the brand despite not having arrived never to series production.
The first thing that impacts is its aesthetics. Those wedge shapes that today seem retro-futuristic to us are typical of the transition from the 60s to the 70s. Suddenly the big sports cars left behind the rounded and muscular forms of the Ferrari 250 to embrace the good news of the straight line. Alfa Romeo Carabo, Lancia Stratos Zero, Ferrari Module… A queue of prototypes to which was added the Mercedes C111 with a body designed to cut the wind like a sword.
In fact, the drag coefficient of the second generation was only 0. Improved until 325'0 of the fourth. Lowest ever achieved! But hey, let's go in parts. As we told you before, Mercedes was testing new technologies, including the Wankel engine, different suspensions and bodies with plastic materials. The best way to make all of this attractive to the public was the first C111.
TWO EVOLUTIONS WITH WANKEL ENGINE
Presented at the 1969 Frankfut Show, the first C111 raised enormous expectations. Its revolutionary design with the fiberglass body astonished. But undoubtedly the greatest novelty was in its engine with a central-rear arrangement. A three-rotor Wankel with direct injection and 280CV at 7.000 rpm capable of propelling the 1100 kilos of the C111 up to 260 km / h.
So far only Mazda had dared to apply the German Felix Wankel's patent. The results had been excellent after the many years of testing culminated with the 1967 Cosmo Sport. However, this was an unknown technology for European brands. Would Mercedes be successful?
The first tests pointed towards yes. In fact, just a few months later, the first evolution of the C1970 was presented at the 111 Geneva Motor Show. With a four-rotor engine the power increased to 370 / 390CV, while the tip did it up to 290 km / h with an acceleration from 0 to 100 set in 5 seconds. This model was already credible for mass production, prompting many interested parties to write blank checks to Mercedes.
However, the C111 (I) never saw the assembly line. The reason? Well, if making the Wankel rotaries useful was a titanic task for Kenichi yamamoto at Mazda… It wasn't going to be easy for Daimler-Benz engineers either. Still the truth is that the engine was running smoothly, delivering power smoothly and efficiently from below.
However consumption was huge (with the 1973 Oil Crisis on the horizon) and poor reliability due to wear of materials in the combustion chamber. Mercedes shelved the idea of marketing the C111, as well as the idea of continuing with the Wankel engines, as did, for example, Citroën. You know, if you want a rotary… Mazda RX range. There is no other way.
A DIESEL OF THE MOST SPORTY
In the mid-70s Mercedes once again set its sights on its truncated prototype saga. Of course, this time to develop diesel technology. And once again with promotional overtones. Actually the idea was simple. What did people associate diesel engines with? Well, heavy and slow industrial vehicles. Was that interesting to a Mercedes willing to sell more and more diesel engines in their cars? Obviously not.
To solve this problem they used the attractive C111. If an experimental sports car like this was powered by diesel engines… People would begin to see this fuel with different eyes. With that idea in mind Mercedes engineers chose the naturally aspirated 5-cylinder in the 240D 3.0 to power it with a turbo. The result was excellent, managing to evolve the engine from the 80s to more than 200CV.
They also improved the aerodynamics considerably. With all this under his belt in June 1976 they moved a team to the Nardo circuit. On this 12-kilometer oval in northern Italy, four pilots would take turns at two-and-a-half-hour intervals to drive the C111(II) for 60 uninterrupted hours. Do you breakdowns? None. And also with an average of 252 km / h. Suddenly it seemed that diesel was not only reliable but also worthy of being in the races!
C111 (III). HEDGEHOGS AND SPEED RECORDS
Excited by the success, the Mercedes engineers returned to the Nardo track in April 1978. They had created a new evolution of the C111 with even more undeniable aerodynamics. What's more, the incorporation of two KKK turbos brought the new 8-cylinder block to approximately 500CV.
The C111 (III) detached itself from any tether that made it look like a street car. It was a whole prototype with which Mercedes tested the turbo technology that marked the 80s. During those days on a track darkened by fog, the C111 flew pulverizing 9 speed records. The averages exceeded 300 km / h, and all this fueled by a consumption of only 16 liters per 100. A resounding success for Mercedes only put into serious difficulties by the appearance of some little suicide bombers.
Hedgehogs One of the two units taken to the circuit suffered an abandonment due to the blowout of the right rear wheel. Shortly before the pilot had noticed the presence of hedgehogs on the asphalt, which can be a problem for a car as heavily grounded as the C111 (III). Even today it is speculated that this accident was caused by running over one of these thorny animals.
With the cause of the damage to the front wing of the second unit there is no speculation. It is certain that it was a hedgehog that was stamped on the front of the C111. Which could be fixed in just two minutes for the peace of mind of the timers. Stopwatches that had yet to set one more record with the futuristic C111 (IV).
C111 (IV). ABSOLUTE SPEED
Although many times it is spoken about the "Three evolutions" of the C111, the truth is that there were five. Although of course, if we get exquisite they can even be more. It is what has the genealogy of a saga of handmade prototypes. All units had elements that set them apart even from their closest companions.
Lineage debates aside, the truth is that the last C111 was the best possible culmination of this car designed to break records with experimental technologies. The point was this: despite the 9 speed records of the C111(III) there was one mark that eluded it. The peak 355 km / h achieved in 854 by a CanAm Porsche 1975/917.
To beat Porsche, Mercedes had to stop fantasizing about the possibilities of diesel. They resorted to a modified gasoline V8 up to 4.820cc with about 500CV and two turbos. With these credentials and even more improved aerodynamics The C111 (IV) broke the world track speed record in Nardo with 403'978 km / h.
After this, you couldn't ask for more from this saga of prototypes. And is that Mercedes had taken from the C111 everything he wanted. An advertising impact, absolute speed records and a multitude of advances in diesel, suspensions, aerodynamics and turbochargers. Even having never reached serial production, we believe that the service record of the C111 is flawless. It impresses even 50 years later.
