Jan 7, 2007
- 100 years ago: The “Dernburg-Wagen” features all-wheel-drive and even all-wheel steering
- Highly sophisticated design by Paul Daimler
- Everyday use in the colony of German South-West Africa, today’s Namibia
The first all-wheel-drive car for everyday use was built by Daimler-Motoren-Gesellschaft (DMG) in 1907. The "Dernburg-Wagen", as it was known, even featured all-wheel steering. It is called after the then Secretary of State of the Colonial Office Bernhard Dernburg who drove many a kilometer in it in Africa the following year.
In fact the all-wheel-drive history of the company began slightly earlier, in 1903, when Paul Daimler laid the foundations for this technology with a first design draft. The first all-wheel-drive vehicle appeared in 1904, and was quickly followed by others. Since then, the watchword has been that all-wheel drive is the best technology when it comes to better traction and safe, assured progress. Over the decades it has been successfully used in all kinds of Mercedes-Benz vehicles, both passenger cars and commercial vehicles, and from vans to heavy-duty trucks. Some of these models, for example the G-Class or the Unimog, have gained a legendary worldwide reputation, and are to be found virtually everywhere on earth. All-wheel drive also scores heavily in day-to-day driving on normal roads, however, as the Mercedes-Benz saloons with 4MATIC demonstrate.
The Dernburg vehicle of 1907
When placing its production order at the beginning of the last century, the German Colonial Office knew precisely what to expect from Daimler-Motoren-Gesellschaft (DMG): a reliable vehicle which would withstand long journeys on unmade roads without complaint, while offering the flexibility that the motor vehicle had already amply demonstrated by the beginning of the last century. The engineer Paul Daimler, son of the company’s founder, was chiefly responsible for the design of the new vehicle which was finally built as a one-off at the factory in Berlin-Marienfelde in 1907. This all-wheel-drive vehicle was based on a DMG commercial vehicle chassis, and had a wheelbase of four meters with a track width of 1.42 meters. The ground clearance of 32 centimeters was not unusually large for the time, as almost all vehicles were often used on heavily rutted unmetalled roads. In 1908 "Allgemeine Automobil-Zeitung" (AAZ) wrote this about Daimler’s design: "All higher road obstacles are overcome by the robust front and rear axles, and the particularly vulnerable lower section of the gearbox housing is enclosed by a strong steel guard between the pressed frame cross-members, which is resistant enough to allow the entire frame to bottom."
The vehicle came on the market for a price of 34,750 Marks. It was fitted with a touring car body having two seats on the chauffeur’s bench and four seats in the rear. Only the rear passengers had doors, and large steps were provided to overcome the entry height of around one meter. Extending almost to the front end and mounted on eight poles, a sunshade prevented the driver from being dazzled even when the sun was low. A luggage rack was mounted on the back for cases or spare tires, with a further, large luggage rack on the roof protected by a tarpaulin. Awnings were affixed below the roof on both sides; these could be lowered to enclose the body and protect the occupants from wind, weather and sand. "To be sure, this Mercedes is not noticeable for its light and elegant construction; it has unmistakable external signs of power and endurance," wrote AAZ, however: "The overall impression of the vehicle has not suffered as a result of the special requirements."
Matched to operating conditions with numerous special features
With a length of around 4.90 meters and a height of a good 2.70 meters including the roof structure, the majestic vehicle weighed around 3.6 tonnes when fully laden with all the special items specified by the Colonial Office, such as a particularly heavy-duty clutch and petrol and coolant reserves for tropical conditions, replacement parts and tools.
Despite this the four-cylinder engine performed manfully, delivering a very respectable output of 35 hp (26 kW) from a displacement of about 6.8 litres at 800 rpm – allowing a maximum speed of around 40 km/h on level tarmac. In view of the intended operating conditions, the climbing ability made possible by the all-wheel drive was however more important: it was an outstanding 25 percent.The vehicle featured permanent all-wheel drive, the engine delivering its power to the four wheels via a sophisticated mechanical system. A shaft connected it to the centrally installed gearbox, which had four forward gears and one reverse gear. From there prop shafts transferred the torque to the front and rear axle differentials, which in turn used bevel gears to split and transfer it to the wheels.
Mechanical components protected against airborne sand
The designer Paul Daimler took special precautions to keep airborne sand out of the drive components. Many of the joints were packed with lubricating grease to keep sand at bay and prevent rapid wear, but the front axle proved to be a real challenge at first: owing to the expected heavy impacts and fine airborne sand, it was not possible to use the usual protection for the bevel gears on the wheels, a telescopic system which followed the steering movements. Daimler shrouded the vulnerable components with a robust, cylindrical sleeve, but because this solution limited the maximum steering angle to just 23 degrees, the vehicle was also equipped with steered wheels at the rear to achieve a reasonable turning circle. The rear wheels were also encapsulated as a protection against airborne sand. One positive side-effect was that the front and rear axle components, including the differentials, wheels and brakes, were of identical construction, which considerably simplified the provision of replacement parts.
The solid steel wheels also served to protect the mechanical components and drum brakes against soiling; wheels with wooden (and more rarely steel) spokes were usual at the time, however these would have let sand into the drive components. Moreover, spoked wheels would have made it practically impossible for the vehicle to free itself after sinking into the sand. The steel wheels were shod with size 930 x 125 pneumatic tires, another unusual feature as solid rubber tires were still in widespread use at that time. Presumably Paul Daimler made this choice to assist the robust leaf springs in their work in view of the vehicle’s high weight. Not unusually for the time, only the rear tires carried a tread while the front tires had a smooth surface. The tire valve was located on the inside of the wheel so that it was not so exposed to damage.
The cooling system was specifically configured for the tropical climate, with a larger cooling surface, a larger cooling mantle around the cylinders and more coolant – the circuit contained 140 litres in total. In addition to the radiator at the front end, a second radiator was mounted on the front bulkhead, enclosing it in horseshoe fashion and extending its honeycomb structure into the slipstream. Both radiators were connected via two side-mounted water reservoirs, and the heated water had to pass through all the lines and tanks before flowing around the cylinders again. "Even in deep sand at only 8 km/h, the cooling system performed admirably during a one-hour endurance test," AAZ reported.
Extensive testing under realistic conditions
At the end of March/beginning of April 1908, the colonial vehicle was subjected to a thorough, 1677-kilometer trial in Germany. The route ran from Berlin-Marienfelde to Stuttgart-Untertürkheim and back. Untertürkheim was reached during the morning of the fourth day, and four days later, the car was back in Marienfelde. The route included off-road sections, too, so as to test the all-wheel drive. “A turn in a deeply ploughed field with a gradient of five to ten percent was negotiated impeccably,” a Colonial Office report stated. “Near Wittenberg the vehicles was driven into a sandpit, in which it sank well up to its axles in the sand, but from which it managed to free itself with ease despite gra-dients of 20 and 21 percent.” In the Thuringian Forest, “a hill approximately 150 meters high was climbed on stony, twisting, narrow roads with gradients of up to 20 percent without difficulty. Even the steering, which was inherently cumbersome as a result of the four-wheel drive, proved itself.” The Colonial Office’s test report was positive.
In May 1908 the vehicle was shipped to Swakopmund in Africa on board the “Kedive”. The Secretary of State at the German Colonial Office, Bernhard Dernburg (1865 -1937) received it for his personal disposal in German South-West Africa one month later. His task was to coordinate and improve relations between the colonies and the motherland. As a result of his travels the all-wheel-drive vehicle was nick-named the "Dernburg-Wagen" many years later. At the same time, these trips served as a general test of the motor vehicle as a means of transport in the colony, and to this purpose the all-wheel-drive “Dernburg” was accompanied at least some of the time by other, rear-wheel-drive, vehicles from Benz and Daimler, namely a seven-seater, extensively armoured car from Benz and three trucks from Daimler.
The author of a travel report from that time described a journey with the Dernburg as follows: “The 600-kilometer trip from Keetmanshoop via Berseba to Gibeon and then from Maltahöhe, Rehoboth to Windhoek was made in a journey time of four days without accident. That is an enormous time-saving, since for the same journey an accomplished rider takes twelve days on horseback […].” And the official was even able to use a mobile communication aid, too: “When [the vehicle] was carrying Secretary of State Dernburg, it also took a field telephone which was able to be tapped into the telegraph wires anywhere along the way.”
In permanent service by the police
Following this trip, the car was made available to the police in German South-West Africa as a means of transport on a permanent basis. A precise log was also kept, showing for instance that the vehicle had covered around 10,000 kilometers by the beginning of 1910.
The car’s driver, who also doubled as its mechanic, was sent by Daimler-Motoren-Gesellschaft along with the vehicle – common practice at the time. And since it belonged to the police, without further ado driver Paul Ritter was made a policeman. Following Dernburg's departure, Ritter remained in the country to look after the car, repeatedly returning to Marienfelde so as to acquire the required spare parts, as well as the repair and maintenance skills to go with them.
The details known about the “Dernburg” all point to the engineering ability of Paul Daimler, who tailored the car’s design precisely to its intended application. Every single feature was thought through so that the vehicle made no compromises with regard to its chief purpose – driving in trackless terrain.
Despite this, the journeys undertaken with the car did not go as smoothly as those involved would have liked. This was because its high weight, due in large measure to the Colonial Office’s special requirements, meant that the pneumatic tires were subjected to a lot of punishment. This meant that, particularly with the amount of off-road driving that had to be done, they only lasted a comparatively short time – 36 tires and 27 inner tubes were used up in the above-mentioned 10,000 kilometers covered by early 1910. Experiments with solid rubber tires proved unsuccessful, since the forces acting on the wheels were then too much, and destroyed them.
The all-wheel drive, by contrast, proved its worth particularly on sandy surfaces, on which the car made better progress than the accompanying rear-wheel-drive trucks. Despite this, after a detailed inspection a police colonel submitted a recommendation to convert the car to pure rear-wheel drive: the numerous components of the all-wheel-drive system made it complicated and time-consuming to maintain and repair. This conversion then apparently did actually take place, but the precise details have not been handed down. There are no records on how the car was used during the First World War. After it, and after the end of German colonialism, all trace of the “Dernburg” was lost – its fate is unknown. Paul Ritter, its driver and mechanic, returned to Marienfelde in 1919 where he once more found employment with Daimler-Motoren-Gesellschaft.