Mercedes Spins Out An Engine For The Future

All big automotive firms have research and development departments, though with some the end product hardly seems to justify the outlay. At the Daimler-Benz factory in Stuttgart, Germany, research and development has always been very strong, and during the period 1952-55, when Mercedes-Benz cars were sweeping all before them on the motor-racing circuits of the world, it could justifiably have been renamed the racing department. All the brains and technology available at Daimler-Benz were put into the project "motor racing" under Director Rudolf Uhlenhaut, with results that still may be seen in the engineering of the passenger cars.

When the racing department reverted to normal research and development work for passenger cars, there was no lessening of activity or experimentation, but, naturally, the outside world and the customers saw only the end products. Such advances as fuel injection, greater braking efficiency, safer chassis structures, improved handling, better suspension systems were the result of work done by Uhlenhaut's experts. Uhlenhaut had no objection to people studying his racing cars, as they would be obsolete before they could be copied. What he did not permit was any breach of security in the experimental department.

This week Daimler-Benz is displaying a new experimental car to the world at the Frankfurt Auto Show. Its engine is not the traditional reciprocating piston engine to be found in nearly all the cars on the road today. It is instead a rotary piston engine, and to me the fact that Daimler-Benz has put it on public view is one of the most significant events in motoring history. I have driven the car, I have discussed the engine at length with the engineers, I have considered the company's legendary reputation for engineering integrity—after all, its roots go right back to the beginning of the automobile and of the reciprocating engine, to the pioneers Gottlieb Daimler and Karl Benz—and at the same time its great caution about new concepts, and the sum of my impressions is that this car contains the engine of the future for Daimler-Benz.

The automotive world has felt the need for a new prime mover for some time now. Gas turbines, steam power and electrical sources of energy are occupying many engineering minds, while rotating pistons have been with us experimentally for a long time. The engine of the German designer Felix Wankel—in which a triangular rotor revolves in a specially shaped chamber, uncovering inlet and exhaust ports as in a two-stroke engine but operating on the four-stroke Otto cycle—had been in the embryo stage for many years. Eventually it was taken up by the German NSU company, which transformed it into practical fact and then sold the patent rights to other firms. Toyo-Kogyo of Japan produced it in two-rotor form in the Mazda car, while NSU went ahead with its two-rotor Ro80.

Daimler-Benz bought an option on the patent. At that time I said to Uhlenhaut, "You've not done that to bury the idea." His reply was, "Of course not. It is an interesting engine." It is this concept, in three-rotor form, that Daimler-Benz has introduced at Frankfurt in a mid-engined, two-seater sports car called the Mercedes C-111. It is designed along the classic lines of the Le Mans-winning Ford GT40 and obviously could go into limited production. At the moment, however, it is being shown as a research and development vehicle, or public test bed, for the rotary engine.

Coming from a small and adventurous manufacturer, the C-111 would have drawn admiration. That an apparently staid and conservative company like Daimler-Benz should produce it has laid the automotive world by the ears. It would have been a pity if the NSU Wankel had proved to be a failure; if the Mazda had failed we could describe it as an Oriental adventure. But by tradition Daimler-Benz must not fail, and so this engine from Stuttgart is a serious portent of what must come. The car is here for all to see, for some to drive and maybe even for some to own. This can mean but one thing: in Stuttgart the reciprocating piston engine is as dead as the dodo. The funeral will not be today, indeed it may not be tomorrow, but the only question is just when it will finally lie down.

What is this rotary Wankel engine and why? To the development engineer, the rotating piston engine is just beginning its useful life, whereas the orthodox reciprocating engine has long been past its prime. For equal capacity the Wankel engine can be produced at about two-thirds of the weight of a conventional engine and in about half the space; it poses far fewer problems of balance and smooth running, has unlimited development possibilities in the rpm sphere and already in its infancy at Daimler-Benz is producing 330 hp (SAE) from 220 cu. in. of displacement in production form. The piston and running chamber can be produced as a single unit or in any multiples thereof. NSU started with one chamber, Mazda went to two, Daimler-Benz to three. The next steps undoubtedly will be four, five or six, depending on how much power is wanted—and each addition takes up very little extra space.

As for the rotary engine's bad reputation in regard to air pollution, this may be said: normally if only 500 cars are produced you do not have to comply with antipollution rules. If 5,000 are produced then you do. Mercedes is aware of all the rules, and however many cars are produced the company will adjust to them.

[In Detroit a senior automotive engineer who has studied and tested the Wankel concept said Mercedes would have to be making giant strides indeed if it were close to solving emission and other problems of volume production—problems which, in his view, are formidable.]

To anyone involved in the motor-racing world there is today only one place for the engine. That is the mid-engine position, just ahead of the rear axle and just behind the driving compartment, and that is where Uhlenhaut has put it in the C-111. Even USAC and Indianapolis have come round to this way of thinking; Ford and Chevrolet have shown that in sports cars they also agree. "For the ultimate in road holding and handling there is no argument against the mid-engined sports car," said Uhlenhaut, "and our compact Wankel fitted neatly into the whole concept." It would also fit neatly into the concept of a traditional front-engine sedan, but that is neither here nor there at the moment. Having driven Porsche, Ford, Lotus, Rover, Lamborghini, Ferrari and de Tomaso cars of the mid-engined coupe layout, I am convinced of the validity of that concept for sports car motoring, and from the time I saw the first single-rotor NSU Wankel experimental engine many years ago I was sold on it, too. To get the two concepts in one vehicle, as with the C-111, was more than I had expected.