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The Automobiles of Benz and Mercedes 1908-1925


Above: The 1916 Benz 18/45 Open Touring Car with the V-shaped radiator that Benz had adopted on some of its models to improve cooling.

Engineering the Automobiles of Benz and Mercedes 1909-1925
By Graham Robson
Photography courtesy of Daimler Archives

A well-known British historian once noted, “Up to 1905 engineers strove to make cars work reliably, but after that they made them work beautifully.” Did it apply to Mercedes and to Benz? Only in that they were ahead of the trend, as usual, for by that time their automobiles were formidably fast, powerful, and reliable.
In the next two decades – and despite an enforced hiatus during World War I, when the so-called civilized world tried to fight itself to a standstill – both companies got on with the business of producing more and more impressive cars. If it was not another generation of Grand Prix winners (Mercedes in 1914) or World Land Speed Record contenders (the Blitzen Benz), it was a serious attempt to make supercharged sports cars work – and all the time there was a constant evolution of styling, of day-to-day durability and engineering. Only the horrors of hyperinflation, which hit Germany in the aftermath of the Great War, caused both Mercedes and Benz to look around, nervously, for partners with which to face the future.
In this historical review, however, we must consider the separate development of the two brands, which were still head-to-head and competing for market leadership, whether in sales or prestige.

Benz – Fast and Furious
Although Mercedes had won the Grand Prix (there was only one per year in those days) in 1908, it was Benz that provided most of the horsepower then, and in the next few seasons. At the end of 1909, Benz launched the massive-engined 200 PS Benz RE, which combined a colossally powerful 200-horsepower, 21.5-liter four-cylinder engine with chain drive to the rear axle. Designed for speed record attempts, until the early 1920s, this was the fastest car in the world – and proved it by taking the Land Speed Record on several occasions before war broke out.

The Type RE  Benz of 1909 on display in the Mercedes-Benz Museum in Stuttgart. The streamlined nacelle surrounding the stub exhausts was added when the car was restored in 1935, and left intact when American Bill Evans refreshed the car in 2005.The car has steel-spoke wire wheels, covered with steel discs for streamlining.

This car was not just fast in a straight line. In the United States, Barney Oldfield used his ex-LSR car (which had achieved 131 mph), known as the “Blitzen Benz,” to win in dirt-track races, while in Europe the 200 PS Benzes won the long-distance town-to-town races as well as speed hill climbs.
Although this was a car built only in tiny numbers – it was the SLS AMG GT3 of its day, both in its stratospheric selling price and in its relative performance – it was a remarkable achievement that, for the moment, Daimler could not match. It was conventional in its engineering with only the huge 1,311 cubic-inch that set it apart. It was well-built and, though quite lofty, an elegant if starkly equipped two-seater roadster.

The 1909 Benz 20/35 displaying the landau body style popular among the upper class, with comfortable seating and a folding top for passengers,  an open compartment for the chauffeur and footman, and a luggage rack on top

At the same time, Benz, led by Hans Nibel, also produced no fewer than 23 different models of 4-cylinder road cars and a pair of sixes before mid-1914. Technically they had not quite settled down to one single design – shaft drive was ascending, but some chain-drive machines were still built – however, with ratings spanning such cars as the 10/20 and the 75/105, there was something for everyone to own. Catering to the mainstream too, Benz produced three different “Prince Henry” sports Tourers, inspired by models produced to contest the high-speed Trials events that carried that name.

1912 Benz 14-30 Saloon

As I have previously written about this period, “The First World War was economically ruinous for Germany.” Nevertheless, it is worth emphasizing that there was no military damage to Benz (or Daimler) factories – bombers lacked the range to reach that far from their bases in the UK or France. During the war, both companies were able to expand their production facilities and pushed ahead with technical development of airplane engines, trucks, and military vehicles that would bear fruit after the war.

Even so, though Benz had produced many fine 6-, 8-, and V-12 aero engines during the war, the company found it difficult to move ahead in 1919 and 1920, when most of the cars put back on sale were improved versions of the 1914 models. However, one conventional postwar model, the 6/18, did have a 1,540cc/4-cylinder diesel engine, though technically Benz’s principal advance was with pre-combustion-chamber diesel engines, originally applied to agricultural tractors and trucks. Their importance was that they were the direct ancestors of Mercedes-Benz diesel engines for passenger cars, which would not be ready until the 1930s.

1923 Benz 10-30 Saloon

The most esoteric new model was the strange mid-engined Rumpler Benz of 1921. Edmund Rumpler designed it – with a six-cylinder 10/30 159-CID engine mounted behind the seats and swing-axle independent rear suspension – and Benz adopted the design as its own. It was the world’s first series-production mid-engined machine.
Unhappily, this was a vision that soon evaporated, for the Nibel/Nallinger hope, that this layout could also be applied to an entire range of sports and touring cars, was soon dashed, and the deal with Rumpler unscrambled in 1922. The special single-seater 2-liter Benz RH (Rennwagen Heckmotor, or rear-engined race car) proved successful in the 1923 Monza Grand Prix.

By 1924, however, Benz’s independent future was already in doubt, as cooperation with Daimler was well advanced. The first talks began in 1923, and the “Agreement of Mutual Intent” was signed in May of 1924. By that time, it was clear that the latest Mercedes cars (and what was already being planned) were well ahead of what Benz had in mind. We now know that the engineering teams began working together from 1923, and that by 1926 the merger to form Daimler-Benz was complete, as was the integration of design and engineering policy.

Mercedes – Nothing But the Best
Mercedes continued to build fast, capable, and, above all, successful road and motor-racing cars. If World War I had not intervened in 1914, Mercedes might have made these machines even faster.
Although it took time for Daimler managers to admit they were wrong to withdraw from motorsport after winning the 1908 Grand Prix, the three-year gap in that series helped cushion the blow. Existing and improved 1908-type race cars continued to win throughout Europe and North America, including success for Ralph DePalma’s car in the American Vanderbilt Cup.

1911 Mercedes-Knight 16/40 Phaeton with its smooth-running 4-liter 4-cylinder sleeve-valved Knight engine

An official return to European racing came in 1913, when new overhead-camshaft-engined cars contested the Sarthe Grand Prix (where one car finished third). The major flourish, however, came in 1914, when a team of brand-new cars met the latest regulations with 115 brake horsepower, 4.5-liter 4-cylinder engines and totally dominated the Grand Prix, which used a hilly circuit centered in Lyons, France. Technically these cars shone not only by having four valves per cylinder (a first for Mercedes, though not quite the first in the world), but by using robust shaft-drive transmissions, practicing diligently, and having a well-drilled pit crew, they outlasted all their opposition, taking first, second, and third places. A year later, one of the cars traveled to Indiana, where DePalma won the Indianapolis 500 race.

1911 Mercedes-Knight Skiff-bodied touring car

It was no coincidence that Allied aircraft engines adopted several technical features of the Mercedes engines. One Mercedes car on display in London was immediately confiscated when war broke out, and the technical features of its engine were found useful in development of aircraft engines in England.
In the meantime, an entire series of new road cars had also been introduced, for Daimler (using the Mercedes badge) seemed determined to match Benz, move for move, in each market sector, no matter what that might be. The record shows that more new models were introduced in those six years than had ever before been launched in the company’s history.

Shaft drive, though, had not taken over completely, and the two drive systems continued to be built, side-by-side, for several years. Technically it was interesting to see shaft drive spread upward, starting with the small, pleasant, but rather gutless 8/18, then gradually spreading up the range via the 14/35, the 22/40, and finally the 28/60 models. All those cars featured overhead-valve engines with exposed overhead-valve mechanisms, which required regular attention from the owner (or, more likely, the chauffeur) to keep everything clean and well lubricated.

Chain drive, however, persisted until 1913 on models like the 22/50, 28/60, 38/80, and 37/90. In the immediate pre-war years, however, there was a general trend away from such crudities, which were increasingly seen as too old-fashioned, and needing even more attention from the owner or his staff.
Another important technical advance occurred when Daimler began to use Knight sleeve-valve engines (which were silent and smooth but – by definition – oil burning). They had been used by other European manufacturers, but four different Stuttgart-produced models – 10/30, 16/40, 16/45, and 25/65 ratings – would appear before war erupted.

The 1914 Mercedes 28/95 Sportwagen, with improved wheels, tires, and suspension over cars built three years earlier

Technically and commercially, Daimler, like Benz, not only kept on working actively during the four horrible years of war, but also used the helter-skelter demands of the military to stretch the performance and capability of its engineering team.
In 1918, however, the German economy, and with it the marketplace for private cars, was in no state to support a complete range of new Mercedes cars. Thus, for the time being, the company chose to reveal the new 28/95 model, a big 6-cylinder model that had actually been prepared for launch in 1914. It was a car directly inspired by the Mercedes racing cars of the period, with a 442-CID engine that derived closely from the DF80 aircraft engine of the era.

The 1915 Mercedes 22-50 saloon, so reliable it was often used as a taxicab

By this time, Mercedes had finally ditched chain drive, so this model had a conventional live rear-axle arrangement. In the early 1920s, it was joined by the 16/50 (which was the last of the Knight-type sleeve-valve engines, in what had been a short trend), and by the small, entry-level, poppet-valve 10/35. Sleeve valves, incidentally, continued to be used by the independent British Daimler company until the mid-1930s.
Without question, though, the major advance made by Mercedes at this time was the introduction of supercharged engines, first in specialized form on racing cars, later on road cars, and finally, and most outstandingly, on hyper-performance sports and limousine-like machines.
Supercharging was originally applied to Mercedes aero engines (two-bladed Roots-type blowers were employed), but the first two road cars to be so equipped were the 6/25/40 and 10/40/65 models of 1921. As with later Mercedes-Benz models, the blower was only brought into use by pushing the accelerator pedal down, beyond what would normally be called the full-throttle position.

The 1926 Mercedes 28/95 was a considerably more mature design than had come before, in both engineering and styling

That was a start, but the launch of a supercharged 28/95 sports car in 1922, with motorsport in mind, was more significant. Here was a car whose 7.3-liter/446-CID 6-cylinder engine had an overhead-camshaft cylinder-head layout and produced 95 horsepower at 1,800 rpm. Because of the success of this car, a 2-liter 4-cylinder supercharged version, with no less than 120 horsepower, was produced within months, and Christian Werner drove it to victory in the Targa Florio and Coppa Florio races of 1924.

There was much more to follow, for two large supercharged 6-cylinder models were also developed – the 15/70/100 (with a 4-liter engine) and the 24/100/140 (6-liter). In this and later cases, the third figure quoted in the model titles referred to the peak engine output with the supercharger engaged.
As a Mercedes-Benz official commented in a corporate history published in 1961, “These cars added to the prestige of Mercedes in whatever part of the world they were seen: in their day they were regarded as the Stradivarius of the road.”

It was at this time that a famous name was linked with Mercedes for the first time – Porsche. Dr. Ferdinand Porsche, who had already made a name for himself in German motor-industry circles, joined Mercedes as technical director in 1923, immediately setting out to enlarge the planned series of supercharged models. His influence was first felt on the Werner car, which was so successful in 1924.
Although it was this family of “Big Six” engines that would make all the headlines in the next decade, I must not forget to mention the 160-horsepower/8-cylinder supercharged 2-liter race car that was developed so rapidly, and successfully, from 1925. Christian Werner, Rudolf Caracciola, and Otto Merz were the most prominent drivers, with this car winning no fewer than 21 of the races it started, including the German Grand Prix on the Avus circuit in 1927.

As already noted in the Benz section, however, all this was overshadowed by the gradual, but relentless, combining of interest of Daimler with Benz. The companies had started cooperating on design and engineering projects in 1923, and then had issued a formal “Agreement of Mutual Intent.” Thereafter we must consider every model built as a Mercedes-Benz, even though there was not yet a combined identification of brands. But that would come.