The Mercedes-Benz C111 with Wankel engine was the most spectacular supercars of the 1969/70 season. motor Klassik remembers a test drive 25 years ago, together with the C 111 developers Dr. Hans Liebold.
At the Mercedes-Benz C111 is absolutely surprising handling. How can one then after all, already 16 year old car so sensitive, so precise, so soft and yet not at all spongy give in, go around curves, braking?
Secret of the outstanding roadholding: Soft suspension - tautly damped
The Mercedes-Benz C111 still meant 1986, a small revelation in terms of road holding, then, as if the car electronics still limited in the second half of the eighties on ignition and injection. ESP, ASR, electronically adjustable dampers, adjustable springs or even hydro-chassis à la Bose was barely dream of. His father, the Mercedes-Benz C111 Project Manager Dr. Hans Liebold, recalled that time, 1986, in Hockenheim: "We have developed the suspension and finally constructed as a race car - with double wishbones at the front and back three times. Otherwise, we are our traditional voting and the Mercedes-Benz C111 in principle remained faithful. We have always sprung relatively soft but firm subdued. "
The set-up of the Mercedes-Benz C111 works still gorgeous, but road ranks not necessarily in the sensuous debates down the pub, the sports car fans in the first place. Here namely the acceleration defended its reputation as the number of all numbers: How fast does the Coupe pace, and where is the speedometer when driving forces and driving resistance finally in balance? Mercedes-Benz once determined the legendary 0-to-100-km / h-value of just 4.8 seconds, at 1,250 kilograms live weight of the Mercedes-Benz C111. however, later measurements yielded only but still highly respectable value of 5.5 seconds in the same discipline, which is why the question arose: How is that possible?
Readings - all a question of set-ups
The explanation: While the slightly slower time the 1250 kg heavy coupe once with road tires and was / is measured at 7,000 rpm onset speed limiter, Mercedes hung the breaker for a single time, pulled racing tires for better traction and turned to 9000 / min - so the first course of the Mercedes-Benz C111 and handed over the 100-km / h mark, and even the clocks stopped the sprint to 100 kph seven tenths swifter.
The findings of the lucky few who were allowed to deal with the sensational coupe grabbed the Mercedes-Benz C111 of the second series to debut at the Geneva show in 1970, in a tightly woven cocoon of highest expectations. The test driver attested the "offspring of the Silver Arrows" perfect workmanship; no place that seemed unfinished, temporarily or superficially patched.
Four-rotor Wankel - paragon of elasticity
Since the stocked even with a sheet metal body and round headlights very first version of the Mercedes-Benz C111 had left more doubts. Who led the rear drive wheels with the final version of the pendulum axles principle à la W 114 and sat on the front suspension of the later S-Class W 116. But heavy load change reactions urged to optimize the chassis, which then already the Mercedes-Benz C111 / 1 attended. And not only the axes were improved. The originally installed three-rotor Wankel 300 hp gave way to a four-disc version, which gave 350 hp. The torque curve promised maximum driving pleasure: Between 4,000 and 7,000 / min were continuously about 400 Newton meters - the great Wankel of the Mercedes-Benz C111, a model of elasticity.
Stalling is virtually impossible: even with the idle speed of 800 / min pulling the rotary engine like a young ox. The atmosphere in the cockpit of the Mercedes-Benz C111wirkt comfortable and somehow familiar. The lightweight wing doors reveals the typical at Mercedes-Benz Pepita fabric of the sixties, and the clocks for speed and speed carry typical of the brand a nice chrome strip.
With the loose agility who just appreciate professional racers, the gears engage in the ZF transmission. BMW drivers know this feeling from the M1, where the same unit - equipped only with other sets of wheels - on duty. At full acceleration, the backrests also checkered related bucket seats in the Mercedes-Benz C111 against the seemingly leaden becoming the driver's body lift, and the Wankel turns without subside so confidently towards the horizon, as if to outclass all reciprocating engines already in second gear. Felix Wankels patent should back then make the "Schüttelhubern" to ashes. But consumption, sealing problems and a very cost-intensive production finally stamped the Wankel to no more than a minor route on the technical roadmap of the automobile.
C 111 with "heavy-duty suspension"
The four-rotor engine in the Mercedes-Benz C111 reminds acoustically never turned out the fatal two-tone, so gladly lay the small Wankel to light. It hums a little behind the rear wall of the cockpit, something firm yet consistently cultivated under load. The twin-disc clutch tames the locomotive-like torque with amazing civil manners. The 350-horsepower Wankel can thus be implemented in a very speedy driving. Mercedes-Benz C111 Project Liebold at the time: "In the experiment, the lap times were on the small track of Hockenheim regularly at 1:17 minutes, but with Dunlop racing tires."
The engine is bolted directly to the frame of the Mercedes-Benz C111, but actually acts as soft and elastic suspended. Liebold: "When we did a trial basis internals our known cultivated current eight-cylinder in the Mercedes-Benz C111, without noise damping Elastiklager as we then sat in the cockpit in front and were afraid of rappelnden beet mill in the engine compartment."
The ingenious suspension qualities of the Mercedes-Benz C111 / 2 of 1970 resulted in the revival of the driving tests in 1986 to an unforeseen forced break. Project Liebold desperate - because he was not a bad road more. The race track in Hockenheim was anyway fairly level, but also the access roads to the Motodrom. "It must be here somewhere but still give a bad road," moaned Liebold, sat down in the prototype that had been dumped only exit in the circle and disappeared towards Speyer. There, finally found a bumpy Page path full of holes, garnished with longitudinal grooves and waves. When the Mercedes-Benz C111 supple rolled across these moguls, the project manager beamed: "It is fabulous. At low speeds still a little stiff, but the sooner, the more comfortable. "So saying, hit the gas and took pleasure when the well worn not acting Versuchswagen bit began leveling the road literally.
Numerous records with Wankel, diesel and gasoline engines
As well Liebold was felt as the Wankel project fell victim in the prime of life of the first oil crisis of 1973? "The motivation that emanated from the Mercedes-Benz C111, was outstanding for the whole team. There were many sad when the project was finished. But it was indeed with aerodynamic tests on, with reciprocating engines and other projects. "The Mercedes-Benz C111 survived as record car. A turbo diesel brought in 1976 no less than 16 world records, including the more than 500 km, with an average of 254 km / h. Two years later, the fourth generation of the Mercedes-Benz C111 was finished, an aerodynamically optimized floor on four wheels. With a diesel engine, it won nine world records, including the back for 500 km, this time with 322 km / h.
404 km / h: with a twin-turbo V8 also the round course record ten kilometers of Mercedes-Benz was the same in Nardo. Before the tires of the Mercedes-Benz C111 had reached their half-hour service life, the Mercedes-Benz C111 three more world records, about 100 miles took an average speed of 367.4 km / h. It all began with a pinch Wankel courage - once a virtue that Daimler-Benz helped tremendously on the jumps.