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Aerodynamics

Applying intelligence to invention

With the valuable support of Prof. Massimo Grandi’s depth of knowledge and illustrative talent

Photo credit: Some images are taken from the book Asi Service "Quando le disegnava il vento" by Massimo Grandi

The Czechoslovakian car maker Tatra was the first in the world to make aerodynamic lines its hallmark. But it would be a big mistake to focus only on this aspect of the work of the company’s true architect, engineer Hans Ledwinka. He, a natural innovator, chose to be flanked by the brilliant streamlining theoretician Paul Jaray. In his role as technical director, Ledwinka built on Jaray’s earliest experiments, such as the 1932 prototype T51, in order to rationalize and modernize the cars built by the firm: having already adopted brakes on all four wheels, he introduced the rear-mounted engine, positioned behind the rear axle, which allowed him to lower the floor, thereby creating more space for the vehicle’s occupants.

Just a year after unveiling the T77, Tatra, to strengthen its position at the high end of the market, presented the 77A with a bigger (3.4L) air-cooled V8 engine. The car also featured numerous esthetic evolutions

This solution also allowed him to eliminate the clumsy footboards that were a common feature at the time. The idea of a rear-mounted, air-cooled engine simplified the entire construction and served to distance the car’s occupants from the source of its noise. On the T77A, Ledwinka also introduced three front seats, with the driver in the middle (does anyone remember the McLaren F1 that came 60 years later?), and, in addition to the two lateral headlights, a central one connected to the steering wheel, whose beam followed the direction of the bend (an “invention” widely promoted by Citroën 30 years later, with the “directional headlights” on its DS 21). 

The visionary innovations included the addition, on the nose, of a centrally positioned headlight connected to the steering wheel that directed the beam of light, illuminating the bends

Magnificent, too, were the 90-degree V8 engines, still air cooled and rear mounted, in perfect harmony with the always carefully tapered lines. Today, everyone remembers the Bugatti Atlantic with its central fin, but in 1935 this had already been a feature of the Tatra T77A for more than a year.

Mounted in the overhang behind the rear axle, the large air-cooled 90-degree V8 engine 8, delivering 75 HP at 3500 rpm made for greater comfort inside the vehicle but undoubtedly impacted on the weight distribution of the car. It is no coincidence that two spare wheels were placed under the front hood, where they were useful for providing some balance

Basically, before it was crushed by the German invasion, the war and then the soviet regime, Tatra had displayed the same dreamlike, often surreal and visionary qualities found in the work of some of its country’s great writers, such as Kafka, Hrabal, Kundera, and Perutz among others. All remarkable and worth exploring in more depth, just like the cars built by Tatra.

The technical choice of a rear-mounted air-cooled engine greatly influenced the design, which included large air intakes positioned just below the roof trim and two generous vent grilles, one on either side of the central fin