The Mercedes-Benz W125 Rekordwagen was an experimental

Experiment

An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...

, high-speed automobile produced in the late 1930s. The streamlined car was derived from the 1937

1937 Grand Prix Season

The 1937 Grand Prix season was the fifth AIACR European Championship season. The championship was won by Rudolf Caracciola, driving for the Mercedes-Benz team...

 open-wheel race car Mercedes-Benz W125

Mercedes-Benz W125

The Mercedes-Benz W125 was a Grand Prix racing car designed by Rudolf Uhlenhaut to race during the 1937 Grand Prix season. The car was used by Rudolf Caracciola to win the 1937 European Championship and W125 drivers also finished in the second, third and fourth positions in the championship.The...

 Formel-Rennwagen, of which also a streamlined version was raced at the non-championship Avusrennen in Berlin

Berlin

Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

.

The main difference to the Grand Prix race car, which had to adhere to the 750 kg (1,653 lb) limit, was the engine. While the GP car had the 8-cylinder inline M125, which was rather tall, the record car was fitted with a V12 engine that was lower, which reduced drag.

The car is on display in the Mercedes-Benz Museum

Mercedes-Benz Museum

The Mercedes-Benz Museum is an automotive museum housed in Stuttgart, Germany. Stuttgart is home to the Mercedes-Benz brand and the international headquarters of Daimler AG. The current building, which stands directly outside the main gate of the Daimler factory in Stuttgart-Untertürkheim, was...

 http://www.mercedes-benz.com/content/mbcom/international/international_website/en/com/international_home/home/heritage_new/history_new/racing_new/record_breaking_vehicles.html in Stuttgart.

1938 Mercedes-Benz W125 specifications

• Engine: MD 25 DAB/3 60 Degree V12
  V12 engine
  A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft....
  
  
• Engine Position: Front Longitudinal
• Aspiration: Twin Roots supercharger
  Supercharger
  A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
  
  s
• Valvetrain: DOHC 4 valves per cylinder
• Displacement: 5,576.75 cc / 340.31 in³ (82.0 x 88.0 mm)
• Compression: 9.17:1
• Power: 541 kW @ 5800 rpm
• Power/displacement 131.97 PS per litre
• Power/weight: 621.1 PS per tonne
• Transmission: 4-speed manual

The record

Rudolf Caracciola

Rudolf Caracciola

Otto Wilhelm Rudolf Caracciola , more commonly Rudolf Caracciola , was a racing driver from Remagen, Germany. He won the European Drivers' Championship, the pre-1950 equivalent of the modern Formula One World Championship, an unsurpassed three times...

's record of 432.7 km/h (268 mph) over the flying kilometre on 28 January 1938, still remains the fastest ever officially timed speed on a public road . It also was the fastest speed ever recorded in Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 until Rico Anthes bettered it with a Top Fuel

Top Fuel

Top Fuel racing is a class of drag racing in which the cars are run on a mix of approximately 90% nitromethane and 10% methanol rather than gasoline or simply methanol. The cars are purpose-built for drag racing, with an exaggerated layout that in some ways resembles open-wheel circuit racing...

 Dragster

Drag racing

Drag racing is a competition in which specially prepared automobiles or motorcycles compete two at a time to be the first to cross a set finish line, from a standing start, in a straight line, over a measured distance, most commonly a ¼-mile straight track....

 on the Hockenheimring

Hockenheimring

The Hockenheimring Baden-Württemberg is an automobile racing track situated near the town of Hockenheim in Baden-Württemberg, Germany, located on Bertha Benz Memorial Route. Amongst other motor racing events, it biennially hosts the Formula One German Grand Prix...

 drag strip

Dragstrip

A dragstrip is a facility for conducting automobile and motorcycle acceleration events such as drag racing. Although a quarter mile is the best known measure for a drag track, many tracks are eighth mile tracks...

.

This record breaking run was made on the Reichs-Autobahn A5

Bundesautobahn 5

is a 445 km long Autobahn in Germany. Its northern end is the Hattenbach triangle intersection is a 445 km (277 mi) long Autobahn in Germany. Its northern end is the Hattenbach triangle intersection is a 445 km (277 mi) long Autobahn in Germany. Its northern end is the...

 between Frankfurt

Frankfurt

Frankfurt am Main , commonly known simply as Frankfurt, is the largest city in the German state of Hesse and the fifth-largest city in Germany, with a 2010 population of 688,249. The urban area had an estimated population of 2,300,000 in 2010...

 and Darmstadt

Darmstadt

Darmstadt is a city in the Bundesland of Hesse in Germany, located in the southern part of the Rhine Main Area.The sandy soils in the Darmstadt area, ill-suited for agriculture in times before industrial fertilisation, prevented any larger settlement from developing, until the city became the seat...

, where onlookers were rattled by the brutal boom of the side spewing exhaust stacks as the silver car hurtled past. By nine that morning, Caracciola and team chief Alfred Neubauer

Alfred Neubauer

Alfred Neubauer was the racing manager of the Mercedes Grand Prix team from 1926 to 1955.-Biography:...

 were having a celebration breakfast at the Park Hotel in Frankfurt.

Sadly, popular driver Bernd Rosemeyer

Bernd Rosemeyer

Bernd Rosemeyer was a German racing driver.- Career :...

 was killed later the same day when trying to beat that record for Auto Union

Auto Union

Auto Union was an amalgamation of four German automobile manufacturers, founded in 1932 and established in 1936 in Chemnitz, Saxony, during the Great Depression. The company has evolved into present day Audi, as a subsidiary of Volkswagen Group....

. This also put an end to the record attempts of Mercedes, even though Hans Stuck

Hans Stuck

Hans Stuck was a German motor racing driver...

 later wanted to beat the overall land speed record

Land speed record

The land speed record is the highest speed achieved by a wheeled vehicle on land. There is no single body for validation and regulation; in practice the Category C flying start regulations are used, officiated by regional or national organizations under the auspices of the Fédération...

 with the Porsche

Porsche

Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....

-designed Mercedes-Benz T80

Mercedes-Benz T80

- External links :**, lists cars that attempted to break the land speed record from 1934 to 1940, including the T80.* at official website of European Car....

which was powered by a 3000 hp airplane engine.