The vehicle was officially known as the Mercedes-Benz T80 or Type 80. Dr. Porsche had first targeted a speed of 342 mph (550 km/h), utilizing a 2,000 hp (1,490 kW) engine. When the car was first planned in 1937, the speed record was held by Malcolm Campbell in the last of his Blue Bird cars at 301.473 mph (485.174 km/h) covering one km (.6 mi) and 301.129 mph (484.620 km/h) covering one mile (1.6 km). However, from 1937 through 1939, George Eyston in Thunderbolt and John Cobb in Railton had raised the record a total of five times, with Cobb achieving 369.74 mph (595.04 km/h) for the km (.6 mi) and 368.86 mph (593.62 km/h) for the mile (1.6 km) in August 1939. As these speed record challengers raised the record, the T80’s speed goal was raised as well. More power was made available from the engine, and when the T80 was nearly finished in 1939, the target speed for its record run was 373 mph (600 km/h) after 3.7 mi (6 km) of acceleration.

The T80 cost 600,000 Reichsmarks to complete; that is about $4 million in today’s USD. Aerodynamics specialist Josef Mikcl helped streamline the car’s body, which was built by aircraft manufacturer Heinkel Flugzeugwerke. The T80 incorporated a Porsche-designed enclosed cockpit, low sloping hood, and rounded fenders. The rear wheels were encased in elongated tail fins to help stabilize the vehicle at speed. Two small wings at the middle of the car provided downforce and ensured stability. The heavily streamlined twin-tailed body achieved a drag coefficient of 0.18, a very low figure even by today’s standards.

Chassis of the T80 with the DB 603 engine connected to the transmission. Note the drive arrangement to the four rear wheels and the fuel tank. (Mercedes-Benz image)

The car had three axles: the front provided steering, and the two rear axles were driven by a 2,717 cu in (44.5 L) Daimler-Benz DB 603 inverted V-12 aircraft engine. Ernst Udet, director of Germany’s Aircraft Procurement and Supply, provided the third DB 603 prototype engine for installation in the T80. The supercharged DB 603 engine with mechanical fuel injection was specially tuned to 3,000 hp (2,240 kW). The engine ran on a special mixture of methyl alcohol (63%), benzene (16%), ethanol (12%), acetone (4.4%), nitrobenzene (2.2%), avgas (2%), and ether (0.4%); it utilized MW (methanol-water) injection for charge cooling and anti-detonation.

Power from the engine was transmitted to the four drive wheels via a hydraulic torque converter to a single-speed final drive. To maintain traction, the T80 had a mechanical “anti-spin control” device. The front and rear wheels each had a sensor to mechanically detect wheel spin. If the rear wheels began to spin faster than the front, fuel to the engine was automatically reduced.

The framework of the T80’s body is shown here, illustrating how much longer the body was than the chassis. (Mercedes-Benz image)

The T80 was 26 ft 8 in (8.128 m) long and 4 ft 1 in (1.245 m) tall. Its body width was 5 ft 9 in (1.753 m) and 10 ft 6 in (3.20 m) wide including the wings. All six wheels were 7 in x 32 in and had a 4 ft 3 in (1.295 m) track. The vehicle weighed about 6,390 lb (2,900 kg).

The T80 vehicle had been unofficially nicknamed Schwarzer Vogel (Black Bird) by Hitler and was to be painted in German nationalistic colors complete with German Eagle and Swastika. Hans Stuck would have driven the T80 over a special stretch of the Dessau Autobahn (now part of the modern A9 Autobahn), which was 82 ft (25 m) wide and 6.2 mi (10 km) long with the median paved over. The record attempt was set for January 1940 and would have been the first absolute land speed record attempt in Germany.

The T80 as it looks now in the Mercedes-Benz Museum. (Mercedes-Benz image)

However, the outbreak of the war prevented the T80 run. In fact, the vehicle’s finishing touches were never completed, and it never moved under its own power. After the record attempt was cancelled, the T80 was garaged. In late February 1940, the DB 603 engine was removed, and the vehicle was stored in Karnten, Austria for the duration of the war. The Mercedes-Benz T80 was unknown outside of Germany until discovered by the Allies after World War II. Fortunately, the T80 survived the war relatively unscathed and was eventually moved into the Mercedes-Benz Museum in Stuttgart, where it is on permanent display in the Silver Arrows – Races & Records Legend room. (The T80’s body is on display. The chassis is in storage at a museum warehouse.)

On 16 September 1947, John Cobb achieved 394.19 mph (634.39 km/h) in the twin Napier Lion-powered Railton Mobil Special, surpassing the T80’s calculated Autobahn record run speed. However, after discovering the T80, the Allies had been quoted an astounding top speed of 465 mph (750 km/h) for the T80. Had the T80 been capable of this estimated top speed, the corresponding record would have been unequaled until 1964 when Craig Breedlove hit 468.72 mph (754.33 km/h) in the jet-powered Spirit of America. In addition, the T80 would still hold the record for the fastest piston-engined, wheel-driven vehicle.

Mercedes-Benz T80 leading the Silver Arrow display at the Mercedes-Benz Museum. (Mercedes-Benz image)