With Audi dominating endurance races, diesel has earned the respect of motorsport only in recent times. But there is a story that dates back to before the Second World War, when a group of designers managed to show the world that diesel engines could do much more than merely power tractors…
Drawings courtesy of Massimo Grandi
On 27 February 1892, Rudolf Diesel obtained the German patent no. 67207 for his engine: “Neue rationelle Wärmekraftmaschine“, the “diesel” engine. The idea was to increase the efficiency of steam engines and the first petrol engines which needed only the high temperature generated by the air compressed in the combustion chamber to ignite the fuel, thus eliminating the ignition device used in internal combustion engines. This new engine offered many advantages in terms of performance, especially its weight, but unfortunately initially it could only be used in fixed installations. And indeed we had to wait until 1903 to see the first applications of the diesel engine in the nautical field, and in 1912 for its first application on a train in Germany.
After the Great War, the use of diesel engines spread quickly among heavy-duty vehicles, trucks and agricultural machinery. The first flight of a plane with a diesel engine took place in Michigan in 1928, the Stinson SM-1DX with a Packard Aero diesel engine.
In the second half of the 1920s, diesel engines for cars began to be considered for production in Germany and in France, as this offered both lower consumption and the production of diesel required fewer refining processes than petrol. Finally, in February 1936 at the Berlin Motor Show, Mercedes presented the first mass-produced car with a diesel engine, the 260 D.
Again in 1936, in October, at the Paris Motor Show another German company, Hanomag, presented its diesel car, the Tipo Rekord D 19.
Hanomag was founded in Hanover, Germany, in 1835. The company was specialised in steam engines, but soon moved on to trains, rolling stock and agricultural equipment. In 1925, Hanomag ventured into the car market with a small utility car that was officially called the 2/10 CV, but was better known as the "Kommissbrot".
Built mostly from plywood covered in fake leather to waterproof it, it was powered by a single-cylinder 500 cc engine mounted at the rear, and the Kommissbrot was one of the typical cyclecars of the time. However, it became highly popular, selling almost 16,000 cars. The success of the Kommissbrot led Hanomag to expand into the mass-production of cars. In 1928, they introduced a more conventional car, the 3/16 CV. This was replaced in 1931 by a new, small car called 1.1 Litre.
However, it was the introduction in 1934 of the 1.5 litre Hanomag Rekord that led the company to success in the German car market. The Hanomag Rekord was the company’s first mid-range model, introduced as the 6/32 PS in the autumn of 1933 and taking the name Rekord in February 1934. As early as 1928, Hanomag had begun works and studies to develop a diesel engine. Initially, the engine was designed for tractors and agricultural machinery, because the then “defects” of the diesel engine, high noise levels and strong vibrations, limited its use to vehicles that didn’t have to ensure comfort for the driver.
In 1936, however, the designers succeeded in creating a compact 1600 cc four-cylinder unit, suitable for installation on a road car. The engine was shown to the public at the Berlin Motor Show in 1936, but where, as mentioned, Mercedes presented a finished diesel car, the 260 D. In fact, even when the complete car was launched in October of the same year, in Paris, the Hanomag Rekord D 19 A Diesel was not in direct competition with the Mercedes 260 D, which was in a different segment, in the mid-car range and so with a lower and more accessible price for the general public.
But on the market things didn't go as planned, the diesel version was hard to sell, and of the 19,000 Hanomag Rekords sold only 1,097 were powered by a diesel engine, and so wishing to promote and advertise the efficiency of its diesel engine, the Hanomag management decided to look to the sportscar world, aiming to conquer the speed record in the under two litres diesel car category.
And thus came the Hanomag-Diesel-Stromlinien-Sportwagen, obtained by coupling a standard Hanomag Diesel Rekord chassis with a 1900 cc D engine.
The standard D engine was designed to save fuel, not for high performance. In fact, the difficulties in adapting the technology of the first fuel injectors to achieve more power was seen as one of the weak points of the diesel engine.
In any case, the team of engineers were able to develop the engine, giving it a bit more punch, but with its 40 HP it could certainly not be described as a high-performance engine, so to compensate the lack of power Hanomag worked on the weight and the aerodynamics, adopting aluminium bodywork with a tubular over-chassis. To produce and assemble the body, Hanomag turned to Wendler in Reutlingen, while for the aerodynamic design they hired Lazar Schargorodsky, and especially the man who we can consider as one of the fathers of, if not the absolute father of, the scientific application of the principles of the principles of aerodynamics to cars: the Austrian aeronautic engineer of Hungarian origins, Paul Jaray.
As explained, the Sportwagen was based on the chassis and mechanics of the Rekord D19. An over-chassis in aluminium pipes was then welded to the chassis to support the body.
The car designed by Jaray faithfully reproduces the diagrams in his patent which, as we know, was substantially based on the principle of a car consisting of two volumes: one bodywork base with different shapes, but with a constant winged profile, on which a second, drop-shaped volume rested.
But Jaray didn’t only patent a car shape, but even a kind of handbook of aerodynamic shapes divided into longitudinal, transversal, front, rear and plan sections that could be cross-referenced and recomposed while always assuring excellent aerodynamic functions.
Our Hanomag, for example, corresponds exactly to the combination QA-AA-og-511 of the patent.
This same combination had been applied by Paul Jaray in a previous project: the 1923 Ley Stromlinien-Wagen.
15 years had passed between the two models, yet little had changed and Jaray remained true to his language. Here it is not a matter of style codes, but rather the continuity of the application of those shapes and those solid geometries that he felt were more aerodynamically efficient, with no concessions to appearance.
However, as I wrote in previous articles, the absolute search for aerodynamic efficiency can add a personal touch of consistent beauty to these special cars, giving them an undoubted charm that still remains today, almost a century later.
In any case, whatever the appearance, the aerodynamic efficiency of the Hanomag Stromlinien was demonstrated by its performance. Despite its small engine, from 8 to 9 February 1939, on a brand-new stretch of the motorway near Dessau, the Hanomag D19 Rekordwagen Diesel driven by Karl Haeberle, a Hanomag engineer, broke a total of four records: the flying 5 km at an average speed of 155.954 km/h, the flying Mile at an average speed of 155.450 km/h, and the kilometre and mile from a standing start with respective averages of 86.87 km/h and 94.481 km/h.
Despite this success, the Hanomag D19 Rekordwagen Diesel fell quickly into oblivion and was later destroyed when the Hanomag facilities in Hanover were bombed, but the Rekordwagen had done what its manufacturers set out to do: to demonstrate to the world that diesel engines were able to do much more than simply power tractors, and that Hanomag was on the front line in diesel engine design.
Massimo Grandi, architect and designer, previously director of the Car Design laboratory at the Design Campus of the Department of Architecture at the University of Florence. Member of the ASI Culture Commission. Among his published works: “La forma della memoria: il progetto della Ferrari Alaspessa”, “Car design workshop”, “Dreaming American Cars”, “Ferrari 550 Alaspessa: dall’idea al progetto”, “Quando le disegnava il vento”, “Il paradigma Scaglione”, “La più veloce: breve storia dei record mondiali di velocità su strada” (with others).