The mid to late 20th century was a golden era for automotive experimentation. During the technological boom of the 1940s, 50s, and 60s, automakers dared to dream beyond the conventional, resulting in a fascinating array of concept cars. From the Chrysler Turbine Car to the nuclear-powered fantasies like the Ford Nucleon, these vehicles pushed the boundaries of imagination and engineering. Germany, too, was deeply involved in this wave of automotive innovation, and towards the end of the 1960s, Mercedes-Benz embarked on an ambitious project: the C 111. This wasn’t just another concept car; it was envisioned as a versatile, near-universal testbed designed to explore and showcase a multitude of advanced technologies. The initial focus of the C111 Mercedes project was to pioneer the rotary engine, a technology that had just been brought into the spotlight by Mazda.
Mercedes-Benz C111 in iconic orange, showcasing its sleek berlinetta design and gullwing doors, a 1969 concept car.
Mercedes-Benz C 111: A Platform for Groundbreaking Technology
Mercedes-Benz, officially established in 1926 through the merger of Daimler Motoren Gesellschaft and Benz & Cie., boasts a rich heritage rooted in automotive pioneering. From its motorsport victories in early Grand Prix racing to its robust military vehicles like the G-Class, and its commitment to luxury and innovation evident in models like the S-Class, Mercedes-Benz has always been at the forefront of automotive engineering. The c111 mercedes project emerged from this very spirit of innovation.
In the late 1960s, instead of developing a series of disparate concept vehicles, Mercedes-Benz conceived the C 111 as a singular, adaptable platform. This approach allowed them to efficiently test a wide spectrum of cutting-edge ideas within a unified framework. The first and most prominent technology to be evaluated within the c111 mercedes program was the Wankel rotary engine.
While Mazda had introduced the first rotary-powered production car a couple of years prior, Mercedes-Benz was determined to explore the potential of this novel engine design. The first c111 mercedes prototype made its debut in 1969 at the IAA in Frankfurt, Germany. This striking vehicle featured a sleek, two-door berlinetta body style, eye-catching gullwing doors, and a vibrant orange paint finish. At the heart of this revolutionary concept car was a three-rotor Wankel engine with a 3.6-liter displacement. Uncommon for engines of that era, this rotary powerplant incorporated direct fuel injection, showcasing Mercedes-Benz’s commitment to advanced engineering.
The evolution of the c111 mercedes continued rapidly. Just a year later, in 1970, Mercedes-Benz unveiled the C 111-II. This iteration featured a more powerful quad-rotor Wankel engine. By adding an extra rotor, the engine’s displacement increased to 4.8 liters, significantly boosting performance. The C 111-II was reported to achieve a top speed of 186 mph, an astonishing figure for a road car of that period. Despite their technological prowess and impressive performance, neither the original c111 mercedes nor the C 111-II would ever reach series production.
C 111 Wankel Engine Performance and Specifications
The development of both Wankel-powered c111 mercedes prototypes was largely conducted in secrecy before the 1969 debut. Mercedes-Benz undertook the engine development in-house, relying on their own engineering expertise. The c111 mercedes project was spearheaded by a compact two-man team. Bruno Sacco, who later became the head of design at Mercedes-Benz in 1975, led the project’s overall direction. Joseph Galitzendorfer was responsible for crafting the c111 mercedes‘s lightweight and aerodynamic fiberglass body.
Here’s a comparative look at the specifications of the two Wankel-engine c111 mercedes concepts:
| Model | 1969 Mercedes-Benz C 111 | 1970 Mercedes-Benz C 111-II |
|---|---|---|
| Engine | 3.6-Liter Tri-Rotor Wankel Rotary | 4.8-Liter Quad-Rotor Wankel Rotary |
| Horsepower | 280 hp @ 7,000 rpm | 349 hp @ 7,000 rpm |
| Torque | 289 lb-ft @ 4,000–5,500 rpm | 317 lb-ft @ 4,000–5,500 rpm |
| Compression Ratio | 9.3:1 | 9.0:1 |
| Specific Output | 77.78 hp per liter | 72.71 hp per liter |
| Top Speed | 162 mph | 180 mph |
Extensive testing of the c111 mercedes prototypes, of which a total of eleven Wankel-equipped versions were produced, led Mercedes-Benz engineers to conclude that the rotary engines did not meet their stringent standards for long-term durability and reliability. While the c111 mercedes program continued to evolve, the Wankel engine initiative was ultimately discontinued for production vehicles. Despite the allure of high performance and a futuristic design, the Wankel-powered c111 mercedes and C 111-II remained as testbeds and dream cars.
Expanding Horizons: The C 111 Program Beyond Rotary Engines
The c111 mercedes project was far from over with the conclusion of the Wankel engine experiments. While eleven C 111 prototypes were dedicated to rotary engine development, the program took a fascinating turn with the twelfth prototype. This version, instead of a rotary engine, was fitted with a turbocharged iteration of Mercedes-Benz’s successful 3.0-liter OM 617A five-cylinder diesel engine. Designated the C 111-IID, this diesel-powered variant debuted in 1976, producing 187 horsepower. The C 111-IID was then deployed to the Nardo Test Track in Italy to pursue endurance records.
Further development in 1978 saw Mercedes-Benz engineers enhance the C 111-IID’s diesel engine. Through further refinement, the engine’s output was increased to 227 horsepower. This upgraded version, named the C 111-IIID, returned to the Nardo Test Track and proceeded to break nine more diesel endurance records. Notably, the diesel c111 mercedes achieved a remarkable run of 9,941 miles at an average speed of 156 mph over a continuous 64-hour period. This was a resounding success, although it would be decades before Mercedes-Benz introduced a production AMG diesel model.
In addition to the diesel endeavors, two c111 mercedes prototypes were chosen to evaluate V8 engines. Engineers replaced the rotary engines in these prototypes with a 3.5-liter V8 engine, paired with a five-speed manual transmission instead of the typical four-speed automatic. Further V8 experimentation led to the C 111-IV. This variant featured a 4.8-liter, turbocharged version of Mercedes-Benz’s 4.5-liter V8, generating an impressive 493 horsepower. In 1979, the C 111-IV reached a top speed exceeding 250 mph at the Nardo Test Track, demonstrating the platform’s immense potential.
Mazda’s Rotary Legacy and the Unfulfilled Promise of the C 111 Rotary
While Mercedes-Benz ultimately moved away from rotary engines in production cars after the c111 mercedes project, Mazda successfully pioneered rotary power for the mass market. In 1967, Mazda launched the Cosmo, a compact two-seater sports car equipped with a small 1.0-liter twin-rotor Wankel engine producing 110 horsepower. The lightweight construction of the Cosmo, weighing only 2,072 pounds, contributed to its reputation as an agile and enjoyable car, especially on winding roads.
Mazda has become synonymous with rotary engines, and the Mazda RX-7 is largely credited with popularizing the rotary engine among car enthusiasts. While rotary engines generally have a reputation for being less durable than conventional piston engines, they offer high-revving characteristics and an exceptional power-to-weight ratio.
Mazda continues to explore rotary technology, keeping the spirit alive. It’s intriguing to consider how AMG’s performance lineage might have evolved had Mercedes-Benz pursued its initial rotary engine plans with the c111 mercedes. Ultimately, the c111 mercedes project stands as a testament to Mercedes-Benz’s commitment to innovation and a fascinating chapter in automotive history, showcasing a versatile platform that explored multiple technological avenues, even if some, like the rotary engine, were not pursued to production.
Sources: Mercedes-Benz, Mazda
[
