In the October 2000 issue of AUVC Nachrichten (link here: https://auvc-archive.blogspot.com/2020/05/auvc-nachrichten-volume-101-october-2000.html and my English translation here: https://dkwautounionproject.blogspot.com/2020/10/horch-trucks-1909-to-1948.html) we learned from Frank Ranicke the history of Horch trucks from the company's early days up to the first years after 1945. In part two he describes truck construction in Zwickau after the war up to 1959.
The "Pioneer" tractor
In a crisis meeting convened by the Auto-Union board on 5 May 1945, it was agreed that the company’s executive management would flee to the west to avoid arrest and reprisal from the advancing Soviet army. The Soviets took control in Zwickau on 1 July 1945 and established an occupation government, known by its acronym SMAD. Auto-Union's plants were classified as category one armaments factories and Soviet engineering teams began systematically stripping the company of plant and machinery for reparations. After losing most of their machine tools and equipment, the company was given a reprieve when it was instructed to begin manufacturing pots, pans and basic necessities for the hard-pressed German people.
Despite the difficult situation, Auto-Union's remaining leadership in Chemnitz pulled together a plan to return to vehicle manufacture. In a memorandum dated 11 October 1945 the new leadership proposed to begin production of the following vehicles: -
1. A 2-ton truck based on the wartime Auto-Union 1500 platform powered by a stock of 70 PS Maybach engines that had been recovered from storage;
2. A light transport tractor for 8 to 10-ton useful weight, driven by the same motor, and;
3. A heavy duty tractor according to a requirement of the civil administration with a 150 HP 6-1 engine.
Auto Union trucks or tractors?
The engineers of Auto-Union's Central Testing Department (ZVA) had developed a motor tractor and in 1940 built 15 prototypes (see above). The tractor was powered by the Wanderer W23 six-cylinder engine, converted to use wood gas. However, this and other promising projects started during the war years, could not be revived due to the loss of critical tooling and machinery from the Auto-Union plants. https://heinkelscooter.blogspot.com/2020/11/motor-und-sport-22-february-1942.html
The Horch plant managed to construct 852 H3 3-ton trucks using the wartime Auto-Union 1500 chassis and recovered Maybach engines, but production ended as soon as the limited supply of engines dried up in 1949. A successor design was not ready to begin series production so SMAD redirected the company to begin building tractors. Germany's agriculture sector was almost entirely dependent on horse and manpower, so mechanization was of higher priority than car and truck production. This was a disappointment for Horch's engineers, who saw themselves as the manufacturers of high-quality cars, but apart from a few bodies for the IFA F9 that the Audi plant had hand built, the company was a long way from series production of passenger cars.
The basis for Horch's first and only tractor, was a vehicle developed by FAMO Fahrzeug-und-Motorenwerke GmbH in 1938. FAMO, formerly of Wroclaw, had been almost exclusively dedicated to tractor construction since 1935, and was an important supplier of tractors and heavy-haulage vehicles for the Wehrmacht. They were regarded as so important a manufacturer that when the war turned in 1944, the company, which was now a stock corporation, was dismantled and relocated to the Junkers plant in Schönebeck on the Elbe. By January 1945 around 50% of the FAMO factory equipment had arrived in Schönebeck, but with the war now lost, the plant was never re-established. An attempt to restart production after the end of the war was derailed by the loss of machinery due to the reparations program. Nevertheless, a handful of the FAMO Type LA wheeled tractors were assembled from stocks of spare parts. After study by the SMAD, the Type LA was approved to go into series production. Components were manufactured in Schönebeck and were shipped to Zwickau for assembly at the Horch plant.
The new Horch "Pioneer" RS O 1/40 (wheeled tractor 40 hp) was presented at the Leipzig Spring Fair in 1949. On 21 May 1949, the first tractors rolled off the hastily improvised assembly line, still bearing the FAMO logo on the radiator. Initial production was only 15 Pioneers per day, but production would be increased to 35 tractors by the end of the year. 350 examples were produced by the end of the year.
The tractor may have received the logo 'Horch', but it bore not the slightest resemblance to anything from the famous Horch factory, being virtually identical to the prewar FAMO tractor. The tractor was powered by the 5-litre FAMO four-cylinder four-stroke 4 F 145 diesel engine, operating at 1250 rpm. The prewar FAMO engine delivered 42-45 hp, while the Pioneer could only manage 40 hp. Experts attributed the loss of power to the use of the IFA EP 453 injection pump. The engine worked according to the pre-chamber process, where the combustion chamber is divided into a main combustion chamber and pre-chamber for partial combustion, and was started with petrol in a complex procedure before switching over to diesel operation. The engine started poorly because the pre-chamber cooled down too quickly due to in-flowing air through the auxiliary carburetor, which was not particularly durable - another symptom of the GDR's problems with specialized parts supply. For this reason, the tractors were often tow-started, which in its turn often led to other engine damage. Once a Pioneer was started successfully, it was was usually not turned off for the whole working day.
The transmission, with five forward and one reverse gear ,was graded differently from the prewar model in order to achieve higher speeds when driving on the road. The front axle construction was also different, increasing the ground clearance from 230 mm to 300 mm.
The RS 01/40 was available with iron wheels (front wheel with cutting rings, rear with spade grabs) or rubber tires, and had everything a tractor needed at that time:- a PTO shaft with a speed of 540 rpm, on which a pulley drive was placed, a spring-loaded towing device, or a lower towing eye (shackle) adjustable laterally on a pulling rail. Some Pioneer owners still rave about the traction of this tractor and its virtually indestructible engine. Consequently quite a few Pioneers have survived and are celebrating their 70th anniversary. Tractor production only lasted at the Horch plant in Zwickau for one and half years. From October 1950, production was moved to the Nordhausen tractor plant where it was to be manufactured in large numbers in the city in the Harz Mountains.
H3A - trucks and buses
The departure of the tractor did not mean a return to car production. Instead, the focus returned to the series production of the truck the Eastern Zone so urgently needed. Development of the successor to the H3 was officially announced in March 1948. Just a year later, the new vehicle appeared in an IFA brochure at the 1949 Leipzig Spring Fair. Series production however, was still a long way off because the Horch works had yet to recover from being stripped to the last light switch and acquiring the machinery to recommence in-house production of a new diesel engine was very difficult to find in the Soviet zone. And yet, the strategy of IFA was to press ahead with vehicle production - no matter how difficult – in order to build up the supplier industry. The slow recovery of the supplier industry, hampered by so many difficulties, would hinder the entire motor vehicle industry of the GDR for decades. In addition, the Horch works’ original engine design was rejected and a had to be reworked. In house engine production only began in April 1949.
In October 1950 the H3A was finally ready. Initially only available in a standard, open platform, the new truck was called the "Patriot." 150 units rolled off the assembly line by the end of the year. In the following year, the production of the new 3-ton Horch truck gradually improved, however, the 2,000 trucks built in 1951 could not meet the enormous demand; especially since a large contingent was assigned for export purposes (a key requirement for IFA was that the new truck would be exportable). The trucks versatility in intercity and urban traffic and the use of the name Horch - which was still used for the plant – and crowned "H" logo went a long to attract foreign customers.
Overall, the H3A was technically a successful vehicle, however, its designers placed great value on robustness and ease of service. The designers had moved away from the more modern cab-over design in favour of a return of the classic hood design which promised faster production. However, they did stipulate a return to a modern design for later models.
The four-cylinder, four-stroke diesel engine, which weighed half a tonne and worked according to the swirl chamber principle, produced 80 hp from a displacement of 6 litres at 2000 revolutions. Its triple-bearing crankshaft with four counterweights turned in a cast iron housing. The cylinders, which were arranged in pairs, carried two-cylinder heads, which enclosed the hanging valves, actuated by a camshaft driven by helical gears. A gear driven double oil pump provided the lubrication and a centrifugal pump circulated the cooling water. The IFA injection pump was still equipped with a manual injection timing adjuster, which was operated from a lever on the dashboard. Three years later, with chassis number 52-0810, the spray adjuster was dropped
https://dkwautounionproject.blogspot.com/2022/08/1953-ifa-h-6.html
Incidentally, the designers had envisaged simple conversion to wood-gas (generator) and methane gas operation. The engine, with the designation EM4 was part of a modular series, which also included the engines EM 2 and EM 6, all manufactured by Horch.
A Fitchel and Sachs two-disc clutch ensured the frictional connection between the engine and the gearbox - also developed by Horch - which had five gears that were in constant mesh (claw-shifted). As with the H3, the power was transmitted to the rear axle via a propeller shaft divided by intermediate bearings. The rear and front axles were hung on two semi-elliptical leaf springs. The spindle nut steering also came from Horch. The chassis was a strong frame consisting of two U-beams, which were connected with cross members. A maximum of six tons load could be expected from the chassis. The manufacturer stated top speed was 80 km/h, for which the piston pump had to deliver 22 litres of diesel per 100 kilometers from the 80 litre tank. There was room for three people in the lightly upholstered, spartan wooden cab.
The H3A was initially available only as a platform truck, with a tarpaulin enclosure available later. However, the Horch truck was designed for versatility, as evidenced by the 26 variants that appeared in the sales programs until 1958. A box body for various purposes started in 1951. In 1952 the Z3 tractor appeared, with a wheelbase shortened from 3250 to 2500 mm. The rear axle ratio had been increased to 6.5 for more pulling power and a compressor flanged to the engine supplied an additional air brake system. With a carrying payload of 2-ton, the Z3 was able to pull a maximum 10-ton trailer load behind it. With only a top speed of 50 km/h, the working days of the Z3 driver could be quite boring. Without a flatbed but with a trailer saddle, the Z3 was still available at the end of 1952 as a towing vehicle for tankers. In the same year, a tipper version became available, constructed by the still private Hunger company from Frankenberg.
Finally, the famous, but limited run of H3B buses saw the light of day this year. The bus, which had been developed in the research and development facility of the IFA (FEW) in Chemnitz (the former Auto Union development center) in April 1951, was assembled in Bautzen, since the bus bodies were designed and manufactured in the Lowa factory there. But shockingly the buses sat in limbo for a long time because the road authorities would not approve them for road use due to insufficient headroom for the passengers! In fact, the vehicle could only be used for internal works traffic and after 230 units, Horch stopped production in 1953. Later, on a low frame manufactured for the H3A livestock transporter from 1957 onwards, a few bus bodies were installed which complied with the transport regulations. However, according to the CMEA decision (CMEA = Council for Mutual Economic Aid, the Eastern European counterpart to the EEC), the GDR was no longer authorised as a bus manufacturer and the Horch bus was withdrawn.
In 1953, the first 20 municipal vehicles for garbage disposal for district towns and especially East Berlin rolled onto the streets. In the same year, the IFA presented the H3A crane, consisting of the Z3 semitrailer, a Hunger semitrailer mounting a SIS electric car crane. This vehicle was constructed by the Bleichert company, which was also privately owned. The following year, the crane could be mounted directly on the H3A chassis. From July 1953, this had been given a new U-profile rear axle, which officially increased the truck's payload to 3.5-tons.
43.5% of all H3A produced in 1953 were exported. The main exporting destinations were Finland, Bulgaria, Turkey and China. In 1954 the export share rose to a record 66%! This pleased the export-dependent GDR economy on the one hand, and on the other hand made it unspeakably difficult for domestic businesses to get the trucks they so urgently needed.
This year saw the introduction of the variants already mentioned, including the three-way tipper with hand-operated oil pump or motorized tilting lift, the refrigerated food transporter, the sewage truck, the construction crew truck for the post and telecommunications system, the workshop trolley, the inspection trolley with lifting platform for street lighting and overhead line construction and finally a cattle transporter. To allow the engine to drive auxiliary units and machinery, a secondary gearbox (geared down or geared up) could be flanged onto the main gearbox of the engine, the drive of which was disengaged from the rear axle. The drive from the power take-off to the special-purpose units was carried out via a cardan shaft.
Because of its versatility, the H3A was also very popular with firefighting services. In the GDR that was the VEB fire extinguisher plant in Görlitz, Jöhstadt and Luckenwalde. Hose cars (type S3), mine safety vehicles, mine rescue vehicles and tank fire trucks (type TLF 15) were created.
From July 1954, a new transmission was used for the H3A, which had a different gradation with a steadily progressive gear sequence. The following year, Horch offered tropical equipment with a tropical cooler, oil bath filter and cyclone (centrifugal filter for increasing exports to Africa) and adjustable windshield. Postal parcel and demolition wagons complemented the special superstructure program in 1955.
In 1956 the truck production in Zwickau reached its peak with 6416 H3A. Because of the high export share to China, for this brother country, the diesel engine had been converted to operate with an anthracite gas generator that worked exactly like a wood gas generator. Anthracite or shiny coal (hard coal with the highest carbon content) was particularly abundant in Tibet and was more readily available to obtain in China than diesel fuel. For demonstration and advertising purposes, three anthracite gas trucks with 70 hp each and an H3S diesel went on a two month high mountain tour through Tibet in October 1956, withstanding the toughest conditions - roads that do not deserve the name, heights up to 5400 m and temperatures down to -30°C required everything from vehicles and drivers (mostly Chinese soldiers). https://dkwautounionproject.blogspot.com/2021/01/1957-kraftfahrzeug-technik-vol-3.html
Speaking of H3S. From 1956 onwards, the H3A could be ordered with two special request packages (internal special requests 14 and 17). They included the gearbox from the large G5 / H6 truck (manufactured in Werdau) as well as a modified platform (SW 14) and/or a wheelbase extended to 3550 mm (SW 17). From then on, H3S were almost exclusively delivered for export. From 1956 there was also a new crankshaft with five lead bronze bearings for all H3A engines.
In the following years the market collapsed significantly, and truck demand fell sharply worldwide. The relatively low payload was now a disadvantage for the Horch truck and falling export figures could only be partially offset by domestic demand. The fall in exports had its effect on the GDR budget and many companies in the GDR, who had long been waiting for a truck, were not given financial approval by the state due to lack of funds.
From February 1, 1957, the VEB Horch motor vehicle plant changed its name to VEB Sachsenring Motor Vehicle and Motor Plant. The name Horch finally disappeared as did the brand symbol "H", which was replaced by an "S" in a circle. This name change did not happen at the insistence of Auto-Union GmbH in Ingolstadt, which owned the brand name and symbol, but rather under pressure from the politicians in the GDR, in an attempt renunciate links to the previous capitalist entity. For Horch’s workers though, the change of their long established and renowned brand logo was simply another reason for declining sales abroad.
The 4-ton truck S-4000
Without much fuss and fanfare, a 4-ton version of the H3A, called the S-4000 (i.e., Sachsenring 4-ton) appeared in the trade magazines in 1958. One of the reasons for the low-key launch was that there was more headline grabbing news from the Horch plant. That year, Horch was finally allowed to return to its prewar tradition of luxury car construction with the six-cylinder Horch P 240 (later Sachsenring P 240). The Horch workers had to invest 2,500 working hours in each of these noble cars, which were available to the upper middle class. In contrast, a H3A truck, required a mere 600 hours.
The automobile starved population of the GDR had been waiting impatiently for their small car, which had been repeatedly promised but only went into series production in autumn 1958. This car, designated the P60, would be better known as the Trabant. To manufacture the new car, the two traditional Zwickau-based companies Audi and Horch were merged together in a single operation on May 1, 1958. The amalgamation of Audi and Horch almost caused a revolution in Zwickau, which was held down, among other things, by promising the Horch works would continue production of trucks and six-cylinder limousines. Inevitably the merger would result in reduction of human resources, but in the end only 56 of the 5,400 Sachsenring (Horch) employees fell victim. No one was unemployed in the GDR, on the contrary; there was a shortage of workers in all areas of East German industry. The job cuts at Horch would probably have been more drastic without the Trabant project. Due to a sharp decline in truck exports, a third fewer trucks were built at the Sachsenring plant in 1957 than in the previous year, and 1958 saw a 50 percent fall from the 1956 volumes.
But back to the new S-4000. While almost indistinguishable on the outside from the H3A (aluminium frame around the windshield, a modified middle part of the radiator grille and the chrome-plated frame of the grille, flashing indicator attached to the B-pillar) the new S-4000 took into account the criticisms of past years, especially from the export customers. The revised the driver's cab offered more comfort and reduced the level of penetrating engine noise. In line with the extended wheelbase, the S-4000 had an enlarged loading area, but that was about all changes compared to the H3A. The press was already announcing a revised engine with 90 hp, but series production could not yet begin with the start of the S-4000. It was not until the end of 1958 that Sachsenring were able to introduce the improved EM 4-22 / 90 engine. The new engine ran somewhat faster than its predecessor at 2200 V/min.
For the next truck in the series, called the H4 in development, the engine would be 100 HP. But that had meant major modifications in production for which there was no money. In particular, the first cycle line for cylinder head production of the EM 4 would have required substantial modification. Now with increased torque (34.1 mkg at 1250 rpm) for better acceleration and more pulling power on the mountain, the engine consumed about 4 liters less (161) per 100 km than before. A synchronized gearbox made the driver's job easier, as did torque-assisted steering. Also new was a compressed air brake connection, which safely braked the approved 4.5-ton total trailer load (with standard version). With these improvements, the type designation of the Sachsenring truck changed in S-4000-1.
In 1958, the H3A and S-4000 rolled off the assembly line for a while, primarily because the large number of special bodies on the H3A could not be immediately transferred to the longer chassis.
There was also the new truck in 1959 as the S-4000-lK with 3250 mm wheelbase (again H3A length) and S-4000-1 T with low frame and long wheelbase of 3900 mm for cattle transporters or furniture trailers. Right-hand drive was already possible with the previous model.
Contrary to previous assurances - from an economic policy point of view there was no other option - on October 16, 1959, the long-overdue decision was made to phase out truck production at the former Horch plant at the end of the year and to relocate production to nearby Werdau, where trucks had been built for years. Along with the production facilities, Sachsenring handed over all truck construction documents, including those from which the GDR long-running truck W 50 later emerged. While the Sachsenring P 240 car had been buried a few months earlier, its engine and the diesel engine series to which the S-4000-1 engine belonged were still being manufactured for a few months before this production was gradually shifted and all capacities belonged exclusively to the Trabant.
by Frank Rönicke
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