Mercedes 15/70/100 PS

Continuing from my last post. Another car depicted in the Tintin adventure, “Tintin in the Land of Soviets” was the Mercedes 15/70/100  PS. This car was a large car built by Daimler from 1924 till 1929. In 1926, the company merged with Benz & CIE and became the Mercedes Benz. Thereafter the car was renamed as Mercedes Benz Type 400.

Design of the car was initiated by Paul Daimler, who left the company in 1922 due to severe disagreements regarding new model policies. The design was completed by Ferdinand Porsche and the car was launched in 1924. Design of this car drew heavily from the company’s successful racing cars. The knowledge gained on the race track was successfully implemented to build a large and fast car.

So what does Mercedes 15/70/100 mean? 15 in the name represented the annual tax horse power. 70 and 100 represented the power produced in PS as claimed by the company. This car was offered with an engine with a switchable supercharger. The car produced 70 PS (69 BHP) without supercharger and  100 PS (99 BHP) with the supercharger switched on.

Now, what is this tax horse power? Intriguing, isn’t it? The tax horsepower was the value used by the governments to calculate the annual tax payable by the owner of a car. In Germany, tax horse-power was calculated by multiplying the number of cylinders in the car’s engine with the cylinder bore and the length of the piston stroke. It took account of the overall engine displacement. The system levied a higher tax horse-power factor to two stroke engined cars as compared to four stroke engined cars. Reason being, a two stroke engine produces power in every alternate stroke while a four stroke engine produces power in every fourth stroke, hence the power produced per unit volume was more in case of a two stroke engine. This system was later changed to taxing cars as per the engine displacement which is used as a norm to this date for classification of cars..

As was the norm in those days, the car was purchased as a chassis and various body types were offered by different coach builders. This car was offered with the following bodies:-

• Six seater Torpedo Body.
• Six seater landaulet.
• Six seater Coupe limousine.
• Six seater Pullman limousine.
• Four door four seater cabriolet.

Mercedes 15/70/100 PS was powered by a 3920 cc, six cylinder in-line engine with a switchable super charger. The engine produced 70 PS with super charger switched off and 100 PS with the supercharger switched on at 3100 rpm. This can be equated to a kind of a programmable ECU at the time, or the eco-power-sport-race switches offered in advanced cars of today. These cars could achieve maximum speeds of 105 km/h (65 mph) and 112 km/h (70 mph).

Mercedes 15/70/100 came with a four speed manual gear box. It had a multi-plate dry disc clutch to transmit the power to the rear wheel. It had a solid front axle. The suspension comprised semi-elliptic leaf springs. Stopping power was provided by mechanical drum brakes on all wheels.

In 1925, most of Europe had right hand drive and hence the steering was placed on the right side. Initially the gear lever was provided to the right of the driver outside the door, but as the design evolved, the gear lever was placed inside the car on the car floor in the middle. This is the norm to this day.

In the book, “Tintin in the Land of Soviets”, Tintin is seen driving the torpedo bodied Mercedes 15/70/100 PS, the car shown in the book is a right hand drive car as Tintin is seen sitting on the right side. It demonstrate Herge’s attention to detail even when making the caricature of a car.