The eternal record.
The “rainmaster” becomes the greatest racing driver of his time.
The conditions are anything but the famous “Sepp Herberger weather”. No rain, no wet ground. Yet precisely these conditions made Rudolf Caracciola so unforgettable – 20 years before Herberger went on to lead the German national football team to its first title in Berne. The experts and the press gave the exceptionally successful German Mercedes-Benz driver the title of “Rainmaster”. After Caracciola repeatedly delivered sensational demonstrations of his prowess on slippery roads, his title was even adopted in English. Despite numerous serious accidents, Rudolf Caracciola was the top racing driver during the 1920s and 1930s, winning the German Grand Prix six times.
During the famous Silver Arrow era from 1934 until 1939, he also won three European Championships. These are the equivalent of today’s familiar Formula One World Championship title.
A speed record in a 736 hp machine.
Today on 28th January 1938, “Caratsch”, as he is called by many, needs anything but rain. The conditions have to be perfect. Here on the level stretch of the brand-new autobahn between Frankfurt and Darmstadt. Today he is sure that he will break the speed record with his W 125, the record-winning Mercedes-Benz 12-cylinder machine. In the previous months, Mercedes-Benz engineers have worked miracles. They have almost perfected the 12-cylinder engine thanks to numerous improvements such as piston clearance, carburetors, intake manifolds and compressor technology.
Aerodynamic drag of a bullet.
With a peak power output of more than 730 hp, he has the most powerful automobile engine yet built by Mercedes-Benz. But will it be enough? Is the car safe enough? Only a few months earlier the predecessor version lost road adherence at approximately 400 km/h and lifted up at the front.
Yet this car is even faster. Thanks to additional modifications the 1,185 kg, 6.2 m long and 1.8 m wide car now has an aerodynamic drag of merely 0.157, a value comparable with a bullet.
The highest speed of all time.
On this cloudy morning the car is polished to a high shine and radiates an aura of power. And it is also considerably safer than its predecessor. It is only 5 o’clock in the morning yet Caracciola is ready and waiting. Nevertheless, he forces himself to wait until the morning frost has thawed. Soon after 8 o’clock the time has come: Squeezed into the almost claustrophobic cockpit, he takes an initial trial run. He seems almost astonished at how “wonderfully the car sits on the road”. Rudolf Caracciola, who is hardly known as a daredevil, now knows no limits. The final preparations are made and at a time at which others begin their working day he sets out to create a new world record the likes of which the world has never seen: The public, the press and the engineers listen to the compressor engine start. Many hold their breath.
World record unbroken - until today.
The excitement only lasts for a few minutes. Then the times from the first trial are announced. The “flying kilometre” measured after the final acceleration was covered at a speed of 428.5 km/h. The return run after changing tires was even faster. After a flying start, Rudolf Caracciola achieved an average speed of 432.7 km/h. The highest speed ever timed on a public road – a record which remains unbroken today.
Tragic death of a friend and competitor.
Yet this day is overshadowed by a tragedy. His competitor and friend, Bernd Rosemeyer, dies a short time later on the same route during his attempt to beat the best time in a car from the successful “Auto Union”. Following the fatal accident, further attempts to break the record were discontinued. Rudolf Caracciola continued to compete in classic racing. In 1946 he wanted to race in Indianapolis; however he suffered an accident during training when he was struck in the face by a bird. In those days the driver’s face was only protected by simple goggles. In 1952 he attempted a comeback at the Mille Miglia in a Mercedes-Benz 300 SL and took fourth place. During the same year he took Swiss citizenship and competed in the Swiss Grand Prix.
Yet as a result of a serious accident he was finally forced to retire from his motor racing career. “Caratsch” died of liver failure on 28th September 1959 in Kassel at the age of 58.
The Mercedes-Benz 12-cylinder W 125 record car.
Mercedes-Benz constructed Caracciola's record-winning car on the basis of the W 125 Grand Prix racing car. Although the 5576 cm³ V12 engine had a lower capacity than the straight eight-cylinder M 125, it was flatter and had significantly better aerodynamics. The body was redesigned to prevent the front of the car from lifting.
Converting the engine cooling to ice eliminated the need for a conventional cooler, reducing the size of the air intake at the front and lowering the aerodynamic drag to a value almost impossible to achieve even with modern vehicles. Additional carburetors served to increase the power output of the DAB V12 compressor engine from 419 kW (570 hp) to approximately 563 kW (765 hp) at an engine speed of 5800 rpm.