Benz 80 hp "Prince Heinrich" car, 1910
After the idea of a handicap for factory drivers, which was practised at the 1909 Prinz-Heinrich-Fahrt, caused some displeasure, this passage was removed from the regulations for the next event. The third Prinz-Heinrich-Fahrt was held from 2 to 8 June 1910 over 1945 kilometres on the route Berlin–Braunschweig–Kassel–Nuremberg–Strasbourg–Metz–Homburg von der Höhe.
Benz & Cie. once again took part in the third edition of the Prinz-Heinrich-Fahrt with a delegation of ten specially designed touring cars. Four of them were equipped with a 5.7-litre engine with 80 hp/59 kW and the other six with a 7.3-litre four-cylinder engine with an output of at least 100 hp/74 kW. Instead of the previously favoured chain drive, both variants now featured a cardan drive for the rear axle. The bodywork was influenced by the "Blitzen-Benz" and featured both a streamlined water box on the radiator and a pointed rear end.
The engine of both variants had a remarkable design feature: it was the first engine designed by Benz & Cie. with four valves per cylinder. With this ultra-modern design, the Mannheim-based company was years ahead of many of its competitors, including Daimler-Motoren-Gesellschaft. It was not until 1914 that the first four-valve engine was used at DMG: in the Mercedes Grand Prix racing car that has remained a legend to this day.
With the exception of the extremely advanced engine design, however, the Benz special touring cars were largely conventional in design. Despite a rated speed of 2200 rpm, the extremely long-stroke four-cylinder had three crankshaft bearings, while the mechanical brake system only acted on the rear wheels and the transmission output shaft. According to reputable sources, the 80 hp cars reached a top speed of around 120 km/h.
Alfred Nadali, Fritz Erle, Otto Philipp and Carl Neumaier took to the starting line in the four 80 hp cars. Despite the considerable efforts put in by the factory, the success of the 1910 Prinz-Heinrich-Fahrt fell well short of expectations. After a total distance of almost 2000 kilometres, an 80 hp car driven by Fritz Erle crossed the finish line in 5th place behind three Austro-Daimlers and an Opel. The fastest 7.3-litre version, on the other hand, only achieved 8th place.
After this last "Prinz-Heinrich-Fahrt", which was organised in the usual manner, Benz & Cie. officially withdrew from the event. In 1911, the tour was organised purely as a touristic trip. Most of the factory cars were subsequently used in various races and touring events and then sold to privateers with sporting ambitions.
A high-profile motorsport event for the Benz "Prinz-Heinrich-Wagen" was the Kaiser Nikolaus Tour organised from the end of June to mid-July 1910, covering a distance of 2880 km from St. Petersburg via Kiev and Moscow back to St. Petersburg. While their rivals from Stuttgart achieved a one-two-three victory, the Benz cars, driven by Arthur Henney, Fritz Erle and Edward Forchheimer, took 5th, 6th and 10th place. While the Henney and Forchheimer cars had engines with cylinder dimensions of 105 x 165 mm and a displacement of 5.7 litres, as in the Prinz-Heinrich-Fahrt, Erle had opted for an even more pronounced long-stroke engine with 100 x 175 mm and a displacement of 5.5 litres. After an eventful vehicle life and a faithful restoration, this special touring car is now part of the Mercedes-Benz Classic collection.