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eastern front tractor

Skoda's Radschlepper Ost: Hitler's idea, Porsche's design

The various wheeled and semi-tracked tactical military vehicles which the German government and industry had designed and produced during the '30s were the cream of contemporary automotive engineering. For the takeover methods and the blitzkrieg tactics of lightning war and a quick victory the elaborate and sophisticated motor vehicles which the Wehrmacht's "elite divisions" used when they overran their neighbouring countries in 1938 - 40 were ideal. They also came out extremely well in parades, propaganda films and the like, but were far less suitable for the reality of the Eastern Front when the fighting there dragged on and got stuck in the winter of 1941/42. The extra hard work under arduous sub-zero temperatures, combined with maintenance problems, took its toll. Additional difficulties stemmed from the chronic shortage of motor vehicles, both on the Eastern Front and elsewhere. Artillery tractors in particular became scarce, partly because of the large amount of prime materials required, not to mention the man-hours needed for their elaborate manufacture. Supply just could not keep up with demand. There was also an acute shortage of horses for the horsedrawn equipment in infantry units.

The transport shortage was solved to some extent by the pressing into service of captured enemy equipment, altough on the other hand this only added to the maintenance and repair problems. Moreover, few vehicles were able to cope adequately with the atrocious going and severe temperatures encountered in Russia. Both the duration of the conflict and the vaste distances into enemy territory had been grossly underrated and these miscalculations were to cost dearly.

It was General von Schell who attempted to reorganize soft-skin vehicle production in Germany. His "Schell Programm" reduced the extensive overall variety of models per category - from motorcycles to trucks - to an acceptable minimum, abandoning the less suitable types and concentrating on mass-production of the best. Typical examples of this simplification scheme were the Volkswagen Kübelwagen, the 1.5-ton Steyr 1500(A) range and the 3-ton Opel "Blitz" trucks

But it was Hitler himself who in November 1941 stated that there was no point in keeping in production at high expense semi-tracked artillery prime movers which would in theory last for 120 years when everybody knew that they could hardly survive more than two years of actual combat life. A new generation of much simplified tractors would have to be devised. Sophistication and superfluous detail had to be abandoned forthwith, if only to preserve high-grade materials - a very valid point indeed.

Specially for the Eastern Front, the Heereswaffenamt Wa.Prüf. 6 (the appropriate Ministry department) arranged with Steyr-Daimler-Puch AG in annexed Austria for the design and manufacture of two new types of artillery tractors: the Radschlepper Ost (wheeled tractor, East) and the Raupenschlepper Ost (tracked tractor, East). For the former requirement the manufacturers came up, in January 1942, with a rather ungainly modification of the standardized Steyr 1500A 1.5-ton 4x4 truck. It featured rigid axles with spoked wheels, entirely of steel and with a diameter of 1.5 metres (nearly 5 feet). The full-track tractor wich they designed was the well-known RSO/01 which, unlike the wheeled one, soon entered quantity production in their own factories as well as those of Auto Union/Wanderer, Gräf & Stift and KHD/Magirus (RSO/03). In addition to the standard model, there was a multiplicity of derivatives, most of which remained in the experimental stage. The big-wheel was never heard of again.

For the wheeled tractor project, the HWA (Heereswaffenamt) had approached Dr.-Ing. h.c. Ferdinand Porsche KG at Stuttgart-Zuffenhausen, the well-known automotive design firm, for an alternative proposal. Ferdinand Porsche (1875 - 1951) was a genius and responsible for a large variety of vehicle designs, ranging from the little KdF "people's car" (Volkswagen, including "Kübel" and amphibious "Schwimmer") to battle tanks. Hitler had in April 1942 made it known that for the new tractor requirement he wanted a tall, four-wheeled, low-speed but powerful and straightforward vehicle, not unlike the Austrian Zugmaschinen of WW1 and Porsche was the obvious choice because he had been largely responsible for such machine as the Austro-Daimler M12 and M16 of that period.

At Porsche's bureau, the order from the HWA was executed under Design No. 175 (becoming Type 175) and the Skoda engineering works in Plzen (Pilsen), Czechoslovakia, were charged with the production of prototypes. Here was another parallel with the WW1 tractors: although bearing the Austro-Daimler name, these had in fact been built by Skoda, who at the time were associated with the Austrian firm. Most of the artillery pieces they pulled were also Skoda manufacture.

Meanwhile, since time was pressing (Hitler wanted the tractors issued to the troops for the forthcoming winter of 1942/43), yet another alternative solution was studied. Latil of Suresnes, Seine, in occupied France and now working for the Wehrmacht under the control and supervision of Daimler-Benz AG, had for many years been supplying heavy four-wheel drive artillery tractors for the French Army. Known as the TAR-type, these had been used in large numbers in the Great War and had been further developed during the '20s and '30s (TAR3, 4, 5, TARH1, 2). Many TARH tractors had been captured by the Wehrmacht in 1939/40 and founds to be of excellent quality. The Germans even employed them, as Latil Schw. Radschlepper (f). The HWA in 1942 ordered Latil to modify their TARH design to meet Hitler's requirements, by the use of large metal wheels, using no rubber, and to get it ready for quantity production, with a thousand requires before the end of the year and a monthly delivery of a thousand units thereafter.

The large wheels were a feature Hitler had great belief in; he probably recalled the performance of the Austro-Daimlers in the 1914-18 conflict, when the Austrians - his compatriots - had used relatively large numbers of them and even the Kaiser had borrowed some, complete with Skoda-built 30.5-cm mortars, in the siege of Belgian forts. Unlike Porsche, Hitler believed them to be just the job for the wretched "roads" in Russia which were just wide tracks of deep mud in which his supposedly mobile armies mired. But how wrong he was! The Ostradschlepper prototypes were tested and while they performed reasonably well in certain types of terrain, they were next to useless in snow, and particularly on icy surfaces and hard snow on metalled roads. Porsche, who had been in Russia and knew the conditions, had formed his own judgment but strangely enough Hitler and his associates never asked for his opinion. Porsche was asked to design the RSO, using as little of the scarce raw materials available as possible (no copper, no rubber for tyres) and carried it out obligingly, without questioning, which was probably just as well. The Reich's top civil servants had a working system all of their own, with strife and financial gain involved, and Porsche knew it was wiser not to interfere with them and their policies. One consequence of this system was that projects like the RSO tended to drag on, without proper supervision, taking too long and failing in the end.

Porsche had worked hard and the first RSO prototypes were read for trials on October 1, 1942, barely seven months after the original orders had been given. In late October the vehicles were put through their paces at the Army's Berka test facilities near Eisenach and on November 20, Albert Speer, the Minister of War Production, witnessed a demonstration. Hitler himself first watched the Skoda and the Latil perform on January 4, 1943, in the vicinity of his headquarters in East Prussia. He was not impressed and as a result he decreed that the production order for a so-called O-series of 200 units which already been given to Skoda (i.e. AG Vorm. Skodawerke, as it was called during the war) was to be halved.

Several improvements were made during these months of tests. The petrol consumption was 2 litres per kilometre, not excessive perhaps for this type of machine (and 10% less than that of the Latil), but petrol was extremely scarce and when Porsche applied to the HWA for another 4000 litres for the continuation of the tests, he was informed in writing that the request would be considered. The HWA was clearly unhappy with the RSO and in August declared that no more petrol was forthcoming because the RSO was a dead duck; Porsche was not amused. Unlike Hitler, he had never really believed that a vehicle like the Radschlepper Ost was the solution to the original problem but he had designed it because he was a designer, not a politician, and had been asked to design it. He reckoned that there were enough competent civil servants and military top brass to decide whether a requirement was valid or not and to what extent. Although Porsche had not entirely given up arguing, he knew that he was backed by Hitler, who, as Führer, had the autority to overrule both the HWA and Speer's ministry. This was often necessary in order to get something done but usually led to inter-departmental conflicts.

Thus, early in 1943, the initial order for RSOs was curtailed and later that year the project terminated altogheter. Time had marched on and the Russian Front requirement for a special tractor was no more....

The writer vividly remember that in the winter of 1944/45 a column of at least a dozen of Skoda RSOs arrived in his home town in occupied Holland. They were painted the standard Einheits shade of yellowish sand and looked quite impressive. Twelve years old and all eyes and ears, he was told by one of the drivers that they were to be used (as a new and secret weapon?) in conjunction with large ploughs, to destroy railway tracks by breaking the sleepers like match sticks. It sounded both barbarous and fantastic. After a while, these Skoda's, which were highly unusual if only because were brand new, were driven to a body works just outside the town, to be camouflage-painted, two at a time. En route to this works, there was a railway level crossing, the approach to it being at a very slight incline. This was in December or January and the roads had frozen up. It also snowed. Now, due to the Wehrmacht's chronic shortage of petrol at the time, it was a rule, if not an order, for a petrol-engined vehicle, at least when empty, to take another (sometimes several others) in tow and the Skoda RSOs were no exception. In the event, two of them were struggling up to the level crossing, iron wheels of the towing unit about to loose grip, when the barriers were lowered to let a train pass and the vehicles halted. After the train had gone, the first Skoda attempted to get moving again but the huge wheels just spinned, albeit at rather a slow rate. The second vehicle was then started up - which took a fair amount of time and effort - in order to move up under its own steam, but to no avail: both machines had all their wheels revolving but did not move an inch. Eventually it was decided to reverse them individually and charge the gradient at "speed"; the tragedy was that they were back at the barriers, these were lowered again and the whole performance had to be repeated. One could hardly help feeling sorry for the not-so-young soldiers who had to fight so hard to cover just a few metres, especially since this was nothing compared with the Eastern Front, for which these tractors had been designed! Still, the poor guys were probably glad that this was Holland and not Smolensk.

What the writer happened to see that day had become clear during the vehicle's official tests two years earlier, when wheels with several types of treads and cleats were tried, none of wich proved satisfactory. In fact, a very adverse report on the RSO had been given by the Army vehicle proving establishment at Kummersdorf. The chief weakness, they had claimed, lay in the wheels, which did not provide sufficient traction and gave rise to excessive vibration, besides tearing the road up very badly.

Although the machine was not supposed to be driven at more than 16 km/h (10 mph), even if it could, it was indeed most uncomfortable on metalled roads, due to the vibration and the noise of the hardly insulated air-cooled engine. In the meantime, something else had happened; members of the SS division Reich, in an effort to keep mobile in Russia in the winter of 1941/42, had been experimenting with a half-track truck conversion. Using bogies and tracks of a British tracked carrier, replacing the rear wheels of a conventional truck, they had devised a relatively low-cost cross-country vehicle with acceptable performance. So successful was this design that the authorities ordered several truck manufacturers to build certain quantities of their 4x2 trucks with these tracked bogies as original factory-installed equipment. This type of half-track truck become known as "Maultier" (Mule) and following comparison trials Hitler in April 1943 decided to axe the whole Ostradschlepper programme in favour of the Maultier, scarce raw materials being diverted from the one project to the other. Other simplified half-tracks, the leichte and schwere Wehrmachtschlepper (light and heavy military tractors) were also produced but it was quite clear at this time that the tide had turned against Germany and these ersatz vehicles were not going to help to reverse the position.

How many Latil FTARH tractors had in the meantime been completed in the West by the time the whole RSO project was dropped is now a matter of speculation, but it is unlikely that many were made. It can be safely assumed that the French labour force was not exactly eager to gets this vehicle into production in the first place and they probably invented enough excuses to considerably delay the action. Neither is it certain exactly how many RSOs were built and delivered by Skoda. Based on surviving evidence we can only assume and estimate that it was somewhere between one and two hundred.

Hitler did not forget about "his" tractor, though. According to Walter J. Spielberger in his book about tractors of the German armies 1871 - 1945 (Vol. 10 in the series Militärfahrzeuge, Motorbuch Verlag, Stuttgart, 1978) Hitler, in December 1944, demanded to know what happened to the O-series RSOs which had been ordered nearly two years earlier, since - in spite of their known shortcomings - at least fifty of them were required as alternative tractors "for special purposes".

The Porsche-designed Skoda and the Latil Radschlepper Ost were dimensionally similar but could be easily told apart. The Latil had a much squarer front and its primitive-looking cab was like the Wehrmacht's wooden universal type, the Einheitsfahrerhaus. The Skoda had more rounded contours and under the skin was remarkably similar to the Austrian WW1 tractors already mentioned. The wheels were driven by four parallel propeller shafts, running fore and aft in pairs, from a large mid-mounted transfer case which also contained the differentials. There was a mechanical locking device to connect the two prop shafts on the right and the two on the left, and thus the right-hand and the left-hand wheels. The transmission incorporated a fluid coupling, which reportedly was not quite up to the job, tending to overheat when pulling away in too high gear and under lenghty overloading; for this reason a conventional single dry plate clutch was also provided.

The main power unit was an air-cooled four-in-line, built up of cylinders from the Porsche-designed Tiger tank engine. Both a petrol (Otto) and a compression ignition (Diesel) version were planned. The four large cylinders had a swept volume of just over 1500 cc each, 6024 cc in total, with the valves in amply-finned heads. With a compression ratio of only 5.45:1 a power output of 90 bhp was achieved at 2,100 rpm. the diesel version was designed to have 18:1 compression ratio and an output of 80 bhp at 2,000 rpm, but it did not reach the production stage.

In order to ensure proper starting, also under extremely low ambient temperatures, an auxiliary engine was provided. This unit, basically half a Volkswagen engine, was flanged to the forward end of the main engine; its main functions were: (a) to pre-heat the inlet manifold, the cylinders and the lubricating oil of the main engine, (b) to act as a crank and (c) to provide heat for the driver's cab. The cab seated three and there was a single bunk across the back; in the wooden rear body there was room for another eight beds, four of them suspended. The non-pleasant appearance of the vehicle was spoiled only by the large and ugly tyre-less wheels. A pneumatic-tyred version with perhaps somewhat higher top speed might, in fact, have been quite a useful piece of equipment. Type 175 information supplied by Porsche in 1982 is at variance in some respects with that of 1942; weights, ground clearance and turning circle figures differ somewhat, but this may be owing to the fact that at least three different types of wheels were experimented with: spoked, perforated and solid, and with various types of spuds.

The Radschlepper Ost, or Porsche 175, may never have seen active service in Russia but it is clear that a quite few found their way to the Western Front, in 1944. After the war, some ten RSOs were discovered in East Germany, where reportedly they stood for several years, parked in the corner of a factory yard. They were eventually broken up, being of no pratical use to anyone.

Whether any have survived now is extremely unlikely. One example, possibly the last, was dug up - literally - at the Porsche work in Stuttgart. It had been buried there in a dike shortly before the Allied armies' arrival in 1945. When rediscovered and brought to the surface in 1960 it was found to be badly deteriorated and apparently considered not to be worthy of restoration and preservation in the Porsche museum. Perhaps nobody was sufficiently proud of it! Alas, that happens to be the way it has gone with many special-interest military vehicles.

BIBLIOGRAPHY: article drawn from "Wheels & Tracks" n. 3, © ed. Battle of Britain Prints International Ltd., London, England