DKW Auto-Union Project: The Development of the DKW F89L Schnellaster

The First Vehicle from Ingolstadt by Thomas Erdmann

Originally published in German in the AUVC Nachrichten Vol 98 October 1999. Link here: https://auvc-archive.blogspot.com/2020/07/auvc-nachrichten-volume-98-october-1999.html

September 3, 1999 was the 50th anniversary of the foundation of Auto-Union GmbH at Ingolstadt, continuing the automotive tradition of Auto-Union AG of Chemnitz, Saxony, which had been liquidated in 1948. Auto-Union GmbH was not the first company at Ingolstadt to bear the name Auto-Union, being proceeded by the 'Central Depot for Auto-Union Spare Parts', or ZDI for short. The ZDI was established on the initiative of some former employees of Auto-Union AG of Chemnitz, including the former board members Dr. Richard Bruhn and Dr. Carl Hahn in order to be able to supply the many pre-war Auto-Union automobiles and motorcycles still on the streets in the western zones of Germany. This included around 60,000 DKW automobiles alone, which urgently needed spare parts to stay on the road. More and more former Auto-Union AG employees found their way to Ingolstadt, especially when it became clear that Auto-Union AG in Chemnitz would be dismantled and liquidated by the Soviet occupying powers.

When exactly the idea arose at ZDI to begin manufacturing complete vehicles again, can no longer be proven. The first documented reference can be found in a contract between Auto-Union AG Chemnitz and the ZDI dated February 11, 1947, in which Auto-Union AG grants the ZDI the right to manufacture and sell "complete products" in addition to Auto-Union spare parts. This contract marks a first step in relocating all activities under the Four Rings to legally sound conditions in West Germany. https://dkwautounionproject.blogspot.com/2020/05/collapse-and-reconstruction-history-of.html

Among the employees who came to Ingolstadt after the war was Kurt Schwenk (above) from the Horch body construction department. He is considered the father of the small DKW delivery van that was to become the first automobile from Ingolstadt. The decision to build a light commercial van appeared obvious because transport capacity was scarce and therefore would be extremely popular, but how do you design and build a car without the appropriate facilities, while struggling through the dire conditions of the early post-war economy. Old doors served as drawing boards, tools were sourced privately, and the office and work rooms were bitterly cold in the winter months, but there was a great community spirit among all employees and the strong will to rebuild the Auto-Union.

The birthplace of the prototype of the DKW F89L Schnellaster ¾ Tonner - this was the name the vehicle would later receive - was the former Zeughaus in Ingolstadt, a brick building that was once used as an army commissariat. Here, the ZDI had already started a modest production line for the 700cc engine, for spare parts purposes. On the first floor of this building, Kurt Schwenk and his staff adapted a DKW F8 chassis so that the pre-war two-cylinder front-wheel drive unit, could be installed rotated by 180 degrees. The more economical use of the engine space allowed the driver's cab to be placed in an oblique front-control position; a modern and future-oriented design even from today's perspective. Above the engine, the round tank of a DKW F8 was mounted on the left, so that fuel flowed down to the carburetor. On the right was an inclined radiator. This arrangement was reversed in the production series. For understandable reasons, the first prototype was given a simple wooden platform like that of the pre-war DKW F8 platform truck. https://dkwautounionproject.blogspot.com/2018/09/1939-dkw-f8-commercials.html To get the finished prototype onto the street, the vehicle had to be carried down the stairs from the first floor of the armory to the ground floor using planks and pulleys. In the summer of 1948 the first test drives were undertaken and further prototypes were built.

The oval F8 chassis is clearly visible in this photograph of the original prototype. Below a later prototype is put through its paces. Note that the headlights poke through the bonnet. In the production model the headlamps were set back in the engine bay shining through glass fixed into the bonnet.

In the meantime, the 'Auto-Union' had been legally established to independently prepare for the start-up of vehicle production. Since the DKW Schnellaster would not only be built as a flatbed but also as a panel van, the F8 frame with its high rear transverse leaf spring (principle of the floating axle) proved to be a hindrance to construction of a flat, continuous vehicle floor. Kurt Schwenk constructed a flat, torsion bar suspension 'Kurbeiachse', to which the rear wheels were individually suspended. This new rear axle, equipped with telescopic shock absorbers, was welded in place of the old suspension axle at the rear end of the F 8 loop frame. Kurt Schwenk received several patents for this axle construction, and decades later, similarly constructed rear axles could still be found in many front-wheel drive automobiles.

Initially the DKW Schnellaster would come on the market in two versions: as a flatbed and as a panel van. The van bodies, however, caused great problems. On the one hand, it was not easy to get large body panels, and on the other hand, the lack of machine tools and welding systems proved to be inadequate. To make matters worse, Auto Union had little practical experience in the construction of all-steel bodies at that time. The company's pre-war body shop at Horch and at the DKW body shop in Spandau manufactured either wooden bodies or mixed wood and steel construction. Consequently, Auto-Union AG had outsourced body construction to specialist body companies such as Glasser in Dresden, Hornig in Meerane, and Baur and Reutter in Stuttgart. The new Auto-Union followed this tried-and-tested solution and outsourced the van body for the Schnellaster from the bodywork company Drauz in Heilbronn.

The DKW F 89 L Schnellaster with three-speed gearbox

The official presentation of the DKW Schnellaster ¾ Tonner took place in May 1949 at the export fair in Hanover. At this point the vehicle still had the oval F8 frame. When the series production of the Schnellaster, now referred to as the F89L (following the nomenclature of the DKW passenger car F89P, which was also being developed in parallel) began in July 1949, the chassis frame had been modified so that it now consisted of two long beams arranged in parallel, that run towards each other in the front third.

For reasons of space, the production of the F89L was moved from the former commissariat (where production of the engine and gearbox remained) to two converted warehouses. The proportion of in-house produced parts was still very low. Most of it was sourced from suppliers, who often had major problems getting the raw material in sufficient quantities and of delivering the required quality. The reject rate of low-quality parts was often considerable, which repeatedly led to the planned production target not being achieved. Nevertheless, a total of 504 Schnellasters had been built by the end of 1949, which were eagerly accepted by the dealers, who had often made payments in advance.

The main goal for 1950 was to expand the product range. In March 1950 the F89L appeared as a station wagon with two side windows and as a bus with four side windows. Like the panel van, both versions were produced by Drauz. There was also a so-called box van with a closed timber structure. Two chassis versions were offered: one with a 2.50 metre wheelbase (box, station wagon, bus, high platform, and low platform), and the other with a 3.00 metre wheelbase (open-plan platform). Of course, the bare chassis and primed cab was also offered for sale. Many customers took advantage of this offer and had special bodies fitted according to their own ideas and wishes. At that time there was hardly a van chassis that was better suited for such purposes, especially since, depending on the planned structure, you could choose between different track widths on the rear axle. From September 1950, the range of factory bodies was supplemented by a cattle truck and bakery van. Special post office and hospital / ambulance bodies were offered. The bus was now also available in a four-door variant with a steel sunroof.

The nation needed to know 'DKW is back!' and so in the summer of 1950 two columns of DKWs drove through the still young Federal Republic to publicize the new DKW program.

What was the customer's reaction to the new DKW Schnellaster? Well, positive at first. The 700 cc 20 HP two-cylinder two-stroke engine was well known from the prewar period and, with more than 100,000 examples now on the road, customers were familiar with its operation and spare part supply was good. Given that the Schnellaster, depending on the version, could carry a permissible load of up to 1.8 tons (total weight), 20 HP naturally could barely pull the proverbial herring from the plate, but other vans of the period didn't do that either.

The Schnellaster could be purchased as a bare cab and chassis enabling the owner to fit a custom body of their choice.

More serious was the fact that some parts of the drive unit, which actually came from the F7- F8 small car, were incapable of dealing with the stresses of commercial use. Torn rubber donut joints, boots and broken hinge joints on the drive shafts, and damage from overheated engines and the steering joints can be found in the warranty reports at that time. It was also shown that the three-speed transmission was unsuitable for the day-to-day operation of a delivery van. In mountain regions there was a special gear with mountain transmission. The engines howled at full revs when loaded vehicles drove at only 50 - 60 km/h on flat roads.

In the course of 1950, production at Ingolstadt began to increase. From January 1950, parallel to the panel van bodies manufactured by Drauz in Heilbronn, a separate production was established. In December of the same year, Drauz delivered the last two bodies and from January 1951, the bus and station wagon bodies were fully manufactured in Ingolstadt.

More extensive changes within the series took place only gradually. In January 1950, the Schnellaster received telescopic shock absorbers at the front. The first 600 cars had the old F8 wishbone-lever shock absorber combination. From August 1950 the engine power was raised to 22 HP. In October 1950, the built-in air intake on the left side of the body was replaced by a blind that could be adjusted from the dashboard. A month later, at the request of customers, a round 'coffee grinder ashtray' was attached to the dashboard. From the spring of 1951, the ventilation slots underneath the windscreen were eliminated. An important change was introduced to the series in November 1951: a new Dynastart from the Siba plant in Plochingen. The original system used up to then had caused repeated electrical disturbances due to the overheating and contamination of the ignition coils inside the Dyna start and the controller. The new Siba Dynastart had a molded case and the regulator was housed separately, with the ignition coils placed outside as pot coils, as per the later three-cylinder engines. A little later, a new cylinder head was introduced, the combustion chamber was no longer hemispherical, but had a spherical cap, which caused a better swirling of the fuel-air mixture and increased the compression ratio to 1: 6.75.

The DKW Schnellaster would become a common feature on the streets of German cities, but the likeable-looking delivery truck with the button eyes also attracted interest abroad, so the F 89 L was also made available with right-hand drive. There was particularly great interest in the fast truck in Spain, where Auto Union GmbH signed a license agreement with Industrias del Motor S.A.(IMOSA) in October 1951. IMOSA originally assembled knock-down kits of the DKW Schnellaster in Vitoria, Spain, however, in September 1955 commenced full licensed production.

Schnellaster with a custom body.

From the beginning of 1951, Ingolstadt worked intensively on the further development of the Schnellaster. The outer appearance would be a little more harmonious but above all, the improved truck would receive a four-speed gearbox. On May 2, 1952, production of the F89L with three speed gearbox came to an end after 17,000 examples had been completed. The last 10 examples were dismantled chassis for export. We will report on the successor, the F89L with four-speed gearbox, in the next issue of Club-Nachrichten, here: https://dkwautounionproject.blogspot.com/2020/12/the-f89l-schnellaster-with-four-speed.html

Contemporary Specifications

AUVC Nachrichten Vol 99 - https://auvc-archive.blogspot.com/2020/09/auvc-nachrichten-volume-99-december-1999.html