Part 5: Hans Nibel – Benz and Mercedes Give Rear Engines A Try
Hans Nibel was born in 1880 in Moravia, then part of Austria-Hungary and now in the Czech Republic. After graduating from the Technical University in Munich in 1904, he went to work for the pioneering automobile manufacturer, Benz & Cie. (Company). He was promoted regularly, and by 1911 was an officer and Chief Technical Director, and by 1922, he was a board member. He was of course involved in many of the numerous successful cars by Benz during this time, including the legendary Blitzen Benz, the fastest racer in the world at the time. We’re going to stick with his involvement with rear engine cars, as Benz, and after their merger, Mercedes-Benz, were significant players in what led to the Volkswagen.
Early on, Nibel saw the inherent and far-reaching potential in Rumpler’s Tropfenwagen, and persuaded Benz to buy a license for the manufacturing rights in order to develop new cars based on Rumpler’s principles as well as to build some racing cars on these principles as test beds. The first result was the 1923 Benz Tropfenwagen RH (Rennwagen Heckmotor), in essence the first modern mid-rear engine racing car.
Nibel made a number of detail changes to Rumpler’s rear suspension and transaxle, including the use of inboard brakes. Although under-powered with its 65 hp DOHC six, two of them made a fine showing on their maiden outing at Monza, and they left a deep impression on all who saw them. That included Ferdinand Porsche and Adolf Hitler, who first briefly met at a race in 1925 where they both saw the Benz Tropfenwagen racers.
After Mercedes and Benz merged in 1926, Nibel had to work under Porsche, who was then Mercedes’ Technical Director. Porsche at the time felt that his line of famous supercharged 200 hp SSK/SSKL front engine racers were still inherently superior, and the little Tropfenwagen racers were abandoned.
It makes me wonder if Harry Miller’s brilliant 1926 FWD Indy racer was inspired by the Benz RH, given that its drive train configuration is essentially the same but turned 180 degrees, thereby driving the front wheels. The key benefit was the same in both: no drive shaft, so as to allow the driver to sit much lower and thus reduce aerodynamic drag. In Indy oval racing, FWD was not at all a disadvantage, as traction was not critical due to running starts and constant high speeds.
After Porsche left Mercedes, he took up the concept with a vengeance, and secured funding from Hitler for the series of brilliant and formidable Auto Union GP cars starting with this Type A in 1934. They were the first mid engine racing cars to win repeatedly, and left an even longer lasting impression on the eventual format of all GP racing cars, some twenty years later. Rumpler was the father of an enduring concept, to this day.
Already in 1927, Nibel was given the go-ahead to develop small rear-engine cars. The first was this 120 prototype from 1931. It was advanced all-round, with a central tube frame, independent suspension and an air-cooled flat four engine in back. Although not put into production, this is as much as a progenitor to the actual Volkswagen (or Tatra) as anything, given that in 1931, neither Porsche or Ledwinka had actually built something remotely comparable.
Apparently there were issues with the air cooled four, as the next evolution, the 130 had a 1.3 L water cooled inline four at the rear. That would turn out to be a fateful decision, as an air-cooled boxer four is inherently much lighter and shorter, critical in the case of rear engine. The 130 went into low-volume production in 1934,
We can see that the front suspension used two transverse leaf springs. Ganz was consulting with Benz at this time, so that may reflect his involvement, although others had used it before. The rear swing axles had coil springs. The obvious issue with this and subsequent other rear engine Mercedes were that they were excessively tail heavy due to their long and heavy inline water-cooled cast iron engines. Ride over the poor surfaces common at the time was superior to the conventional smaller Mercedes models, and at the low-moderate speeds of the time, handling was considered adequate. But at the limits it was capable of doing what every excessively tail-heavy swing axle car could do, and that was neither pleasant nor safe.
In the 150H sports car of 1934, Nibel reverted to the mid-rear engine format, essentially an update of the Benz Tropfenwagen racer. It used many 130H chassis components, and its drive train flipped 180 degrees, as well as an enlarged and more powerful SOHC engine. As such, it was the first production mid-engine sports car.
More intriguing was the 150H Coupe, which won several long-distance road races in 1934, and looks more than a bit like a somewhat cut-down Volkswagen.
Mercedes’s final rear engine car was the 170H (“H” for “Heck”, meaning rear), which replaced the 130 in 1936. It was introduced at the same time as the traditional front engine 170V (V for “Vorn” or Front), so as to provide consumers the option of two different formats with the same basic engine.
Unsurprisingly, the traditional 170V trounced the 170H in sales, thanks to a bigger trunk, no tricky handling at the limit, and perhaps most importantly, its traditional large upright Mercedes radiator grille on a long hood in front. Mercedes buyers tended to be conservative. The fact that the 170H was considerably more expensive was the final coffin nail, and the plug was pulled in 1939.
That ended Mercedes’ unhappy experiment with rear engines, although it would yet play a role in the development of the Volkswagen, in part due to its experience in building small numbers of rear engine cars like the 150H.
Part 6: Hans Ledwinka – Innovator or Copycat?
Hans Ledwinka, born in Klosterneuburg, Austria in 1878, played a complicated role in the genetics of the Volkswagen. Ledwinka was a brilliant engineer credited with many innovations, and I have sung his praises here at CC. If the tone of this chapter comes across a bit negative, it’s only because it’s been quite fashionable for some time to attribute more to Ledwinka than is justified on the facts. In particular, it’s all too common to come across claims that the Volkswagen was simply a copy-cat Tatra.
Tatra did go to court over patent infringement by Volkswagen, and eventually won a judgement in their favor well after the war, and VW paid Tatra damages (details further down). This alone, as well as certain obvious visual and technical similarities between the Beetle and the Tatras has been used repeatedly to reinforce that the myth that Porsche essentially ripped off Ledwinka, and used the protection of Hitler to do so.
It’s actually a lot more complicated (or not) than that, and I’m going to focus on primarily those issues here. But for what it’s worth, Ledwinka was no stranger to using others’ ideas and designs too.
We’ll skip over Ledwinka’s early years at Nesselsdorfer, where as an 18 year old he joined Edmund Rumpler in designing some less than stellar early horseless carriages, as well his much more successful S4 and S6 cars of the teens. After a stint with Steyr, Ledwinka returned to Nesselsdorfer to design a light, small, and relatively affordable car, one that would be his first enduring and perhaps his greatest masterpiece, the first to bear the name Tatra, the T11. It was designed between 1921 and 1922, and went into production in 1923.
It was a highly successful and quite advanced synthesis of several existing components: a central tube, that would serve both as the frame of the car as well as enclosing the drive shaft. Affixed rigidly at the rear there was the differential housing, from which emanated the swing axles. And attached equally rigidly at the front of the tube was an air cooled boxer twin, over the solid front axle. The engine’s flywheel had vanes and doubled as the cooling fan, whose output was directed to the cylinders via shrouding.
The central tube as a primary carrying member goes back to the 1908 Rover 8 HP, and the swing axles are of course from his former boss, Edmund Rumpler. But the combination was essentially new, and Ledwinka wasted no time patenting all of it, and more, including variations with the engine at the rear, although that was strictly on paper at the time. But that patent, for a rear engine attached to a transaxle, was also used in legal action against Ganz, no less.
The T11 and its successor, the T12, developed a superb reputation for their ruggedness, economy of operation and capabilities. Eventually, Ledwinka added two more cylinders to create the T30, and its evolution, the 57. These were highly capable cars, and Ledwinka’s extensive experience with air-cooled boxer engines made him the world’s leading expert on them, most critically their cooling systems.
Other air cooled engines back then typically just relied on large fins and the passing air over them at speed, or some sort of primitive blower assist. But Ledwinka had been refining the blower and its ducts for years, and as can be seen on this T57 engine, it looks quite advanced and was well proven. Ledwinka patented several variations on the theme of ducted fan air cooling schemes, so general in their scope that there was essentially no way around them. That would include the Volkswagen.
In 1930, Ledwinka’s son Erich started working at Tatra. Along with design engineer Erich Übelacker, they instigated the idea of hanging Tatra’s air cooled twin in the rear of the T57. They already had the right engine for the job, and by 1930, rear engines were the hot new thing. This resulted in the T57 – V570, a cobbled-up two-passenger prototype. According to the definitive book “Tatra – The Legacy of Hans Ledwinka“, this occurred in late 1931.
Meaning after Mercedes had already built its all-new four passenger 120H prototype (left) and by which time Porsche was drawing up his T12 (right).
Ironically, the T57-V570 was unsuccessful, because the air cooling did not work adequately when enclosed in the trunk of the T57’s body, and thus the V570 was abandoned.
Tatra’s second effort was more ambitious, with a new four-passenger body that was developed with aerodynamic input from Paul Jaray. It too used the 854 cc boxer twin. This was the V570 prototype—never developed into a production model—and was completed in early 1933.
Again, that’s one full year after Porsche had built this very similar-looking T12 (1932), for motorcycle maker Zündapp. But Google “Tatra V570 VW” or something similar, and one will find dozens of articles claiming that the Tatra V570 was ripped off by Porsche and that the V570 was the true basis for the Volkswagen. Really?
Of course Porsche was influenced by Ledwinka’s work, to one degree or another, most of all the ducted forced-air cooling. There are other similarities that have been brought as evidence of the borrowing by Porsche from Tatra, such as his early use of twin transverse leaf spring for the front suspension, but that was being done by others well before Ledwinka, including the 1915 Cornelian (Porsche later developed his distinctive twin-trailing arm torsion bar front suspension). There’s the distinctive central backbone/hump in the VW’s platform chassis, but that too was used well before Ledwinka popularized it. And of course the same goes for the swing axle rear suspension.
Ledwinka and Porsche were friends going way back, and often met and discussed their work. As Ledwinka himself said: “Well sometimes Porsche looked over my shoulder and sometimes I looked over his”. Fair enough.
Coinciding with their early efforts at building their first rear engine car, in 1932, Tatra also embraced aerodynamics. We’ve shown that this was hardly new, but the interest in applying it was growing everywhere after Rumpler’s influential Tropfenwagen. Since Tatra had no experience with that, Paul Jaray was paid for the license to apply his principles to Tatra’s cars. Tatra and Ledwinka were aggressive patent filers, and in 1933, they applied for patents in Germany with this application titled “Improvements in or relating to Automobiles.” Take a good look at Fig.3.
Here’s Fig.3 along with another drawing of an extremely similar vehicle (top). Way too similar, actually. What is it?
Here it is, a write up of Tom Tjaarda’s “revolutionary” aerodynamic car in the July 1931 issue of Modern Mechanics, two years earlier. Rear engine, four wheel independent suspension…everything the Tatra streamliner would soon sport, even the dorsal fin.
Here’s Tjaarda with his “Sterkenberg” prototype. He didn’t find a manufacturer in the US willing to take on its further development or manufacture. And we know that Tatra didn’t pay him for using his design as their starting point,as well as in their own patent drawings.
In 1933, Tjaarda went to work for Briggs, the leading builder of all-steel and later unibody car bodies. There he developed this second version, shown at the 1933-1934 Century of Progress exhibition in Chicago.
Ford bought the rights this time, and it was majorly reworked into their 1936 Lincoln Zephyr, using solid axle Model T suspension and with a water cooled flathead V12 engine in front. America was not ready to join the rear-engine independent-suspension revolution.
Not even ten years later, with Tucker’s Torpedo, essentially an updated version of Tjaarda’s concept.
But Tatra was ready to dive in fully and quickly. Work started on the large T77 in 1932, and the prototype was finished in early 1934. It featured a 2.9 L air cooled V8, still looking still quite similar to the Tjaarda protype. It used transverse leaf springs in front, as that was still the most common way to achieve IFS, and in the rear it had quarter elliptic leafs as used by Rumpler.
The T77 was built in limited quantities from 1934 through 1938, and there were many variations in its body details, as this was essentially a hand-built car. Its excellent aerodynamics resulted in the ability to cruise effortlessly at up to 90 mph with only 75 hp. Of course it was expensive too, and as such we’ll leave it for now, and take it up again with Adolf Hitler.
Not surprisingly given its short gestation, the T77 had a number of shortcomings, including some very wicked handling qualities. And it was not suitable for serial production. So in 1936, the definitive Tatra, the T87, arrived; shorter without sacrificing much interior room, better visibility, and handled…a bit less wickedly. It quickly became the favorite of the SS.
And it soon spawned a slightly shorter four cylinder version, the T97, which shared a number of body parts with the T87, but used a 1.75L flat four of 40hp and a top speed of some 80 mph.
The T97 is also often used in the conspiracy theories that it was the true basis of the Volkswagen, that the T97 was blatantly ripped off by Porsche to create the Beetle. By 1936, the Beetle was already on its third version of development, and getting quite close to its final one. Of course there are certain general similarities, but really only to those that think either of these cars were somehow unique. We’ve spent considerable time here showing that none of the features of them was unique, except in some details. And that Porsche started out in this line of development in 1931, a year or two before Tatra.
The T97 conspiracy theory is reinforced by the fact that Hitler did have its production ended in 1938 after he invaded Czechoslovakia. The theory says that he did that because the T97 was too similar to the Volkswagen, and thus would have competed with it. It certainly wasn’t because the T97 would actually present a sales challenge to the coming Volkswagen. The T97 was significantly bigger, a full six-seater, and priced several times higher than the VW’s planned price. And Tatra did not have the facilities to build the T97 or any cars in significant volumes. It was a low-volume producer and the VW was to be built by the millions.
By 1938, all of greater Germany’s economy was controlled increasingly by diktat, as it was in a massive military build up. Tatra, which also built trucks, became a significant military contractor, and it’s more likely that Hitler killed the T97 to make its production facilities available for that. He did keep the T87 in production as it was a favorite of his commanders. Ledwinka would be imprisoned for six years after the war by the new communist regime for war crimes.
As to the lawsuit brought against VW by Tatra, it had three claims of patent infringement: 1.) on the position of the engine (at the rear of the car inline with the transaxle); 2.) the location of the transmission; and 3.) certain details of the VW’s forced air cooling system ducting. Tatra’s patents on air cooling were so numerous that they essentially covered all the bases.
Porsche knew that there was no way not to infringe on the ducted cooling patents, as did Hitler, who told him not to worry about it, that the issue would soon go away. It did, when he invaded Czechoslovakia. But it came back after the war, in 1961, when the Düsseldorf Regional Court ruled that only claim #3 (details of cooling ducts) was valid, and VW made a settlement with Tatra.
After his imprisonment ended, Ledwinka moved to Munich where in his retirement he advocated tirelessly for the principles of swing axles on trucks (as Tatra trucks still use today), in order to improve driver comfort and for improved off-road adhesion. He did not share in the monetary settlement from VW, and refused numerous awards. He passed away in 1967.
It’s rather ironic that Ledwinka is so often identified with the Volkswagen—as its inspiration or ripped-off victim—considering that the well-documented timelines clearly show he was rather late to the rear-engine and streamlined party. And that he borrowed from others to be able to design and build his early streamlined rear engine cars. Presumably it’s because Tatra’s T77 and T87 are just so compelling. They were the first to be produced in any numbers, albeit modest ones, and as such are assumed to be the source of everything that followed in their delicate wake.