The OEM gives an exclusive tour of its Untertürkheim proving ground in Germany
This year Mercedes-Benz celebrates 50 years since its test track in Untertürkheim was opened.
The proving ground in Germany was first opened following a request by Dr Fritz Nallinger, head of development at Daimler-Benz, who stressed its need in order to analyze the company’s wide range of vehicles, from passenger cars and race cars to buses and trucks.
Nallinger’s suggestion was for a long stretch of company-owned land directly adjacent to the Untertürkheim plant, known as the ‘bottleneck’, to be converted for the facility. A planning application was submitted to the City of Stuttgart in January 1955, and in July 1956 the board of management at Daimler-Benz gave the green light for the plans. In 1957 the first phase of the test track became operational.
The layout at that time included a skid pad featuring concentrically arranged circular tracks with different surfaces vehicles can be tested on blue basalt, concrete, slippery asphalt and large cobblestones. The integrated sprinkler system enables wet surface testing.
Later it became evident that the test track was still inadequate for the many and varied demands of the passenger car and commercial vehicle test departments; engineers were keen for better facilities that would enable high-speed, durability and rough-road testing. They also wanted to be able to test commercial vehicles on steep inclines. The site was gradually expanded to incorporate these features.
Take a tour
The cumulative length of all test sections is 15,460m, including 3,018m of high-speed test track. The two parallel tracks are connected by steep-bank curves with a diameter of 100m. A source of wonder back then were the seven different incline sections with gradients of between 5% and 70%, along with the steep-bank curve with a transverse inclination of up to 90%. A maximum speed of 200km/h is theoretically possible on this steep banking, but this would physically be almost unendurable for a human being.
For testing purposes it is particularly important instead to be able to drive through the steep-bank curve at 150km/h with no hands on the wheel. At this point, namely, there are no longer any lateral forces impacting on the tires and the vehicle remains on track through the bend without any steering input. The driver’s weight nevertheless rises by a factor of 3.1, pressing them into the seat.
Another indispensable part of durability test facilities is the heathland test section. This rough-road track was built to scale to replicate a particularly poor stretch of road in the Lüneburg Heath in the north of Germany as it was in the early 1950s. Durability tests are also conducted on the so-called washboard, boneshaker and potholed sections. Tests are so stressful that drivers have to switch every two hours. Further features of the circuit include extreme distortion tracks for commercial vehicles and off-roaders, along with ramps used to force extreme spring compression and rebound.
Handling safety in adverse weather conditions is tested on the 34m-long crosswind section. This features 16 blowers designed to produce side winds of speeds up to 100km/h.
The slalom section at the facility was a world-first introduced by the head of vehicle testing at the time, Rudolf Uhlenhaut. This was a stretch of track designed to test the driving stability of suspensions at high speed and during abrupt changes of lane, using measurement loops embedded in the road surface to deliver electronic data.
Since the expansion work was completed 50 years ago the 8.4ha site, with its cumulative 15.5km of different test tracks, has continued to be adapted for new requirements. For example, a section of road with low-noise ‘whisper asphalt’ surface, was created for the measurement of noise.
May 3, 2017
