We harboured faint hopes five years ago and wrote, "Perhaps one day it will be possible to get a Schwaben Wankel running again using technology from a 3D printer. Until then, C-111 fans can fall back on pictures and graphics of the engines."
They can be found not only in our picture gallery, but also extensively in book form. To coincide with the anniversary, the book "Mercedes-Benz C 111" was published at the end of October 2019 with the participation of Wolfgang Kalbhenn, who once worked on the C 111. Based on the extensive original documents in the Mercedes-Benz Classic archives, it tells the story of the vehicle and the development of the Wankel engine at Mercedes.
Gallery: 50 years of the Mercedes-Benz C 111
Now the time has actually come, not only is the C-111 bible already available in its second edition, but as part of Monterey Car Week, the Mercedes C 111-II from 1970 with the original Wankel engine will make its debut at the Mercedes-Benz Classic Centre in August 2024 after being overhauled.
"With its Wankel engine, high-tech materials, breathtaking driving performance and futuristic design, it is a fascinating time machine today. It brings the visionary spirit of 1970 to life. We are bringing this innovative and 350 PS sports car to Pebble Beach for the first time in more than 50 years. A true super sports car with up to 186 mph top speed - back in 1970!", says Marcus Breitschwerdt, CEO Mercedes-Benz Heritage GmbH.
A visionary design in terms of shape, drive and materials: The Mercedes C 111 is one of the most spectacular concept cars in automotive history. It appeared on the horizon as bright as a fixed star, only to later fail to go into series production, to the regret of many fans. Nevertheless, the orange-coloured wedge remains in the memory of an entire generation, with children and young people in particular admiring the C 111 as a toy car, in a quartet game or as a poster on the wall.
At its debut at the International Motor Show in Frankfurt am Main (IAA) in 1969, the C 111 thrilled experts and the public alike. The Wankel-engined sports car never went into series production, but quickly became an icon. Successful record-breaking vehicles were built on its basis from 1975 onwards.
But first things first: in September 1969, people crowded around the futuristic super sports car that Mercedes presented to the world at the IAA in Frankfurt. Nobody had expected such a vehicle, especially not from Mercedes. Was this Gullwing perhaps the legitimate successor to the legendary 300 SL Gullwing (W 198) from 1954?
It didn't turn out to be, although high-ranking customers even sent blank cheques to Untertürkheim. The C 111 remained a purely experimental vehicle and did not go into series production. Only twelve of the two versions from 1969 and 1970 were built.
In the fascinating mid-engined sports car, the Stuttgart-based brand primarily tested the drive with a rotary piston engine based on the principle developed by Felix Wankel. The C111 from 1969 used a three-disc Wankel engine with three 600 cubic centimetre chambers and an output of 280 PS.
In the further developed C111-II, which was presented just six months later at the Geneva Motor Show in spring 1970, it was a four-disc engine with a chamber volume of four times 600 cubic centimetres and 350 PS. Now, 54 years later, this version can once again be driven with Wankel.
Mercedes-Benz C 111-II experimental vehicle with four-disc Wankel engine, 1970
Mercedes had already been working on the Wankel engine under NSU licence since 1961, and at that time it promised true miracles. Wolf-Dieter Bensinger, who knew Felix Wankel from pre-war times, was in charge at the Swabian company. At the same time, vehicle designs were created, such as the SLX mid-engined sports car from 1964, which was conceived by Bruno Sacco and designed by Mercedes designer Giorgio Batistella.
Despite major challenges, the company's engineers continued to develop the Wankel engine with courage and a love of discovery. Head of Development Prof. Dr Hans Scherenberg reported in 1967 that the fuel consumption of the Wankel was around 50 per cent higher than that of a reciprocating piston engine of the same power in a V-shape. Ultimately, fuel consumption and emissions behaviour at the time argued against series production of the powerful and smooth-running Wankel engine.
Reliability could also be improved, although the installation of Wankel engines for the SL of the 107 series and the 123 mid-range series was considered. But bad luck stuck to the Wankel: Rudolf Uhlenhaut, head of passenger car development and C-111 promoter, retired in 1972, the first oil crisis followed in 1973 and Bensinger died in 1974. Mercedes finally ended Wankel engine development at the beginning of 1976.
C 101: The concrete realisation of the Wankel sports car began under this abbreviation at the end of 1968. Rudolf Uhlenhaut (photo above), once the father of the legendary 300 SL, was responsible for the project. The project manager is Dr Hans Liebold, Head of Advanced Development. The fascinating design was created by a team led by Joseph Gallitzendörfer, and Bruno Sacco, who had recently switched from pre-development to styling, coordinated the body development of the spectacular sports car.
The first test drive of the first complete vehicle takes place on the Hockenheimring on 15 July 1969. The experimental vehicle was then presented to the public at the IAA in September under the name C 111 - thus avoiding a conflict with the type designations protected by Peugeot with the middle digit zero.
In addition to the Wankel engine, the C 111 will also test technologies that have so far only been implemented in rudimentary form in series car production, including bodies made of glass fibre-reinforced plastic (GRP) and joining techniques such as bonding (gluing) and riveting. However, there are also problems here that are not conducive to series production. The unusual orange metallic paint finish also contributed to the fame of the C 111.
Mercedes C 111 in all three versions with Wankel engine
The name "Weißherbst", borrowed from viticulture, refers to the dazzling orange/rosé colouring of the popular wines. The exhibition vehicle presented at the IAA in Frankfurt is the first C 111 in this spectacular colour scheme. The other vehicles in the first series, which will be used as demonstration cars during the IAA, are still finished in "white effect paint", but will later also be repainted in white autumn.
The admiration for the C 111 is reflected in the media: "Today, the four-disc version would not only be the most comfortable and quietest, but also the fastest such car. I am firmly convinced that there are thousands of customers in the world for such a car," said Paul Frère in the trade magazine "auto motor und sport", issue 8/1970.
"The car that takes your breath away", writes the "Deutsche Auto-Zeitung". The trade magazine "Road & Track" hopes in November 1969: "If we tell them how much we like it [the C 111], then maybe they will build it". The magazine "Hobby" featured the further developed C 111-II on its cover in April 1970 and described it in the magazine as a "four-disc rocket from Untertürkheim".
The experimental vehicle impressed not only with its visionary concept, but also with its excellent performance for its era. The first version of the C 111 reached a top speed of 162 mph, and the C 111-II even reached 186 mph. In the car quartet games of the early 1970s, this catapulted the C 111 into the league of top trumps. The C 111 even became the title motif in the 1970/71 quartets "Die Deutschen Autos" (The German Cars) by Altenburg-Stralsunder Spielkarten (ASS) and "Schnelle Sportwagen" (Fast Sports Cars) by Bielefelder Spielkarten in 1970.
After the Wankel was discontinued in 1976, the second career of the C 111 as a record-breaking car with reciprocating piston engines began in the same year. A total of two versions with five-cylinder turbodiesel engines (C 111-II D in 1976 and C 111-III in 1978) and the C 111-IV with a V8 petrol engine in 1979 were produced.
On the high-speed track in Nardò, Italy, the C 111 record-breaking vehicles set numerous records, including the circuit world record of 403.978 km/h (251 mph) with the C 111-IV on 5 May 1979. However, it no longer had much to do with the original model in terms of looks (see picture below).
Mercedes-Benz C 111 with turbodiesel
The last test drives took place in 1989, after which the Wankel versions of the C 111 were mothballed in order to preserve the few remaining rotary engines for the future. In addition, there were practically no spare parts available for the engines, which were internally known as M 950. As a compromise, the specialists at Mercedes-Benz Classic made one of these dream sports cars from their collection ready to drive again in a different way in 2014.
Mercedes classics:
To do this, they used a 3.5-litre V8 engine from the M 116 model series, as used thousands of times in the S-Class and SL. This engine had already been installed in a C 111 in 1970 for comparison and testing purposes - exactly in the vehicle now being used again for this purpose.