The Mystery of the Vanished Streamliner

Built in the darkening days before the Second World War to win a race that was never run, the 540K Special Streamliner later disappeared in the turmoil of postwar Germany. For decades the remnants of this unique aluminum-bodied behemoth lay lost and forgotten.
 
Article Gary Anderson & Stephan McKeown
Images Royce Rumsey, Kyle Burt, Daimler Archive
 
One day in the spring of 2011, while checking inventory at the Mercedes-Benz Classic Center in Stuttgart, Service Manager Ralph Hettich ran across an entry for a 540K chassis with a 1938 build date. Curiously, Mercedes-Benz Museum documents listed this 540K as first entering the Classic collection in 1955. Intrigued, Hettich then unearthed the old chassis in the museum storage facilities. A jumble of dusty wooden boxes were piled nearby. Investigating, he discovered the boxes were full of what appeared to be parts for a Mercedes-Benz 540K. What’s more, the part numbers matched those on original production records for the nearby chassis. But what vehicle had they come from?

To answer that question, Hettich searched the archives for any 540Ks shipped around that same time, but not recorded among the 540Ks currently known to the Classic Center. One particular vehicle began to stand out, a 540K listed in the records as a “Special Streamliner” shipped to the Frankfurt dealer on order from Dunlop Tires in Hanau, Germany, in June 1938, but de-registered in 1948.

Sure enough, the chassis number of this mystery car matched that of the chassis in the storage facility. Plus, among the parts nearby was a rear-end differential with a 2.9:1 gear ratio designed for high-speed travel rather than the standard 3.07:1 of customer 540Ks. Closer inspection disclosed torn fragments of aluminum bodywork and traces of olive drab paints on the chassis. This must indeed be the chassis of the vanished Special Streamliner. Final confirmation in hand, Hettich found himself inexorably launched on a project that would culminate at Pebble Beach in August of this year.

Aerodynamics and speed were exciting new technical frontiers in the 1930s. Aided by the development of wind tunnels, streamlining was all the rage. Speed records fell on land and water, high-speed Autobahns were built and the Silver Arrows of Mercedes-Benz and Auto Union were besting all comers from the rest of Europe and America.
To demonstrate the superiority of Adolf Hitler’s Germany and Benito Mussolini’s Italy, plans were drawn up for a long-distance race from Berlin to Rome to take place in 1938. There was no question that Daimler-Benz would build a contender for it.

Using the chassis of a supercharged 540K, the Special Vehicles Production Unit in Sindelfingen would create the most advanced and fastest long-distance road car ever built. To win the race, strategists calculated that the Streamliner must average more than 150 kilometers per hour (93 miles per hour) for the entire 1,500 kilometers from Berlin to Rome. To achieve such high sustained speeds, the aerodynamics of a 180-horsepower 540K would be improved by a aluminum body developed in the new Untertürkheim wind tunnel.
Hettich located a detailed set of original plans for the Streamliner, carefully filed away in the Daimler Classic Archives. At the front of this unique vehicle, the distinctive V-shaped 500-series radiator would be tucked under a curved nose and grille. The star emblem would be painted on the nose, just like Mercedes racecars; the windshield and windows curved; and headlights, signal lights, and door handles designed to minimize drag. At the rear, the fluidly curved trunk would taper to a soft point, with the number plate mounted under a transparent cover. Vents behind the doors could be opened to provide cooling airflow to the cabin.

The result, recorded on build documents after wind tunnel tests in 1938, was a drag coefficient of 0.36, an achievement that other cars wouldn’t match for another 75 years. Though the tests confirmed the fitness of the design, a major stumbling block soon arose: finding suitable tires to mount on the gorgeous center-lock racing wheels.
Dunlop of Germany simply had no tires that could carry the weight of the Streamliner – even with its lightweight body – at the speed and for the distance required for the race. As a result, Mercedes-Benz was forced to substitute another race entry. However, after Germany annexed Austria and shifted its economy to a wartime footing in March 1938, the Berlin to Rome race was canceled.

Even so, Dunlop decided the Streamliner would be a perfect test bed for new high-performance airplane tires. Final assembly was finished and the car delivered to Dunlop in Frankfurt on June 25, 1938. The Streamliner would continue to be used for tire development for the next seven years, being converted to run on natural gas during the war.
After the war, it was noticed by a Dunlop staff member in Stuttgart, painted olive drab and driven by a U.S. Army officer, and reported to the authorities. It was subsequently deregistered in Hanau in April 1948. There was no information as to when the aluminum body was removed. However, with aluminum sheeting in short supply after the war – and easily pounded out for other uses – the body panels were likely ripped or cut off the chassis, leaving scraps of olive-drab aluminum under the bolt heads on the frame, just as Hettich found them.

Sure of his facts, Hettich drew up a proposal to re-create the Special Streamliner. The 540K chassis, which was still in excellent condition, would be reassembled and reconditioned at Germany’s Classic Center. Wherever possible, original components would be retained and only as much mechanical work performed as deemed necessary to return the  rare car to its original running condition.

Simultaneously, the wooden frame and aluminum body panels would be re-created working with an outside specialist and guided by the original plans. With his restoration proposal approved, Hettich was placed in overall charge of the project. Work began in earnest in February 2013.
By May 2014, restoration was complete. The car looked identical in every respect to period archive pictures. Satisfyingly, wind-tunnel tests verified the 1938 data; while on the test track, the car reached 167 kilometers per hour without supercharger and 186 with supercharger engaged. Benefiting from modern tire technology, results easily surpassed the original targets from 1938.

But true satisfaction for Hettich and his team came on the Thursday in August before the concours, as the car rolled off the transporter in Carmel for the Pebble Beach Tour d’Elegance. Having completed a thorough mechanical inspection at the Classic Center in Irvine after the long trip from Germany, Hettich reported a smooth and relaxed tour; the Streamliner performed perfectly. By late afternoon, the car was back on display in the Star Lounge, resting up for its drive to the world-famous show field early Sunday morning.
After Monterey, the once-vanished, now-glorious Streamliner will return home to Stuttgart and take pride of place at the Classic Center Museum.