Friday 12 May 2017

1936 AAZ Road Test DKW Schwebeklasse


The latest automotive offspring presented to us, the DKW Schwebeklasse, owes its existence to the desire of many automobile enthusiasts to successfully implement the two-stroke engine, which is difficult to beat for its simplicity, in a more powerful. rear-wheel drive car. The car’s four-cylinder two-stroke engine has undergone many changes over the years because it was by no means easy to develop the engine and chassis to the point where the whole vehicle could be something special.

During the development of this type, Auto-Union was aware that the two-stroke engine alone is not enough to make a car equipped in this way sufficiently desirable to buyers. There must be other characteristics in the Schwebeklasse, in particular an above-average performance, extremely simple chassis and structure and, last but not least, economic efficiency that is at least equal to that achieved with a four-stroke engine of the same power. Anyone who has closely followed the development of the Schweberklasse will know that the latter problem was the hardest to solve.

We can confirm in advance that the numerous challenges have been solved. The engine is characterized by a pair of v-shaped cylinder blocks, each of which is fed by a charging pump. This principle has not changed since this type of engine was born in 1930, but the displacement has increased. Instead of one carburettor, there are now two. Because of the increase in output achieved, the crankshaft had to be strengthened. Fuel consumption, which rises sharply with higher engine power, had to be brought back to its original level. The sum of all these efforts is now included in today's Schwebeklasse engine.

We determined a fuel consumption rate of 11.9 litres per 100 kilometres. Based on our previous experiences [with the Big DKW 4=8], that was a big surprise for us since the engine's performance has theoretically at least remained the same. In addition, the great equilibrium and smoothness of the engine are pleasantly noticeable, characteristics that result from the twice as high frequency of work cycles and lack of valves compared to the four-stroke engine. The pulling power of the engine at low speeds has increased considerably, so that one is no longer tempted to drive the car at very high revs in the lower gears to achieve sufficient acceleration, as was the case with the forerunners of this type. The elastic suspension of the motor ensures that vibration is not transmitted to the frame. In short, we had a really good overall impression of the engine.

The fact is that the engine is by no means the only thing that gives the Schwebeklasse its peculiarity. There is a lot to be said for the use of the free wheel, which is less of a necessity here than with the two-cylinder two-stroke engines, but rather a truly pleasant addition. In contrast to the Meisterklasse, the freewheel, which can be switched on and off from the driver's seat, does not run between the engine and the transmission, but between the transmission and the rear axle. The result of this arrangement is that when the freewheel is switched on, the gearbox is made independent of the speed of the rear wheels. Shifting down to lower gears is particularly pleasant; you don't need to clutch or double-declutch, an advantage that will certainly impress some drivers who, despite our regular explanations still do not practice this art.

Another point worth mentioning is the use of "floating axes" at the front and rear. These are normal rigid axles, each connected to the frame by an overhead transverse spring. The purpose of this well-known construction is to prevent the most prominent disadvantage of the transverse suspension, namely the tendency of the structure to lean sideways in sharp curves, by preventing the spring from engaging at the high centre of gravity of the vehicle. This alternative creates the possibility of retaining the transverse spring, which most closely meets the requirement for a low weight of the unsprung mass. It must be recognized that this method as used in the Schwebeklasse provides excellent ride and suspension properties. On both good and bad roads, it was easy to assume that it was anything but a rigid front axle.

Furthermore, the Schwebeklasse was deliberately designed to be as spacious as possible. The success is such that one looks in vain for similar space comfort in larger cars. This advantage is reinforced by the excellent visibility. The large windshield in combination with the forward sloping hood allows a far above average view of the road surface ahead. The windshield is made of security glass.

The self-supporting plywood body of the Schwebeklasse gave no cause for complaint. Its resistance to torsion meets the requirements that can be reasonably placed on it. It should not be forgotten that the centre of gravity provided by the floating axle spring suspension saves some torsional stress.

Our test of the car on the road and in the country was an almost pleasant event. The car has nothing exciting about it but performs its duty as in a pleasantly inconspicuous meadow. Even in uncomfortable situations, the engine power is sufficient thanks to the well-graded gearbox. When the car is high above ground clearance, it is easy to take the rutted sand paths if you shift down to the correspondingly low gear in good time. The checked car reached a top speed of 96.2 km/h over the flying kilometre, and 69.6 km/h from a standing start: - both values that are quite satisfactory. The speedometer was not one of those with short legs: its advance was +2 percent.

The driving characteristics of the Schwebeklasse left nothing to be desired. The suspension worked perfectly both when the car was fully occupied and when the car was only occupied by one person. The steering remained calm; only in the high-speed test did it show a few complaints, which were soon explained by the unequal air pressure of the two front wheels. It is well known that even the best independent suspension and steering does not help against uneven tyre pressure. What is noticeable is the rigidity of the Schwebeklasse, which is unusual for a rigid axle. Even in bends with an undulating road surface, in which the majority of vehicles like to hike sideways into the bushes, the road grip of the tyres was hardly interrupted. This phenomenon is mainly explained by the good relationship between wheelbase and track width, but also by the transverse suspension, which, in the structure of the semi-elliptical long spring, follows the movements of the axle.

The spaciousness of the body has already been discussed; it is made possible by the short construction length and forward positioning of the motor. The dashboard contains a speedometer, gasoline meter and ammeter in a single-sighted instrument; a green signal light is also provided to warn the driver as soon as the oil level has fallen to a dangerously low level. The dimmer switch and winker switch are on the steering wheel. The fuel tank is placed in front.

As a summary, it can be said that the Schwebeklasse among vehicles up to about 1 1/2 litre capacity occupies a special position because of the spaciousness and comfort of the body and an unusually large trunk. Nevertheless, the weight of the vehicle is kept within moderate limits so that the 32 hp engine gives it sufficient liveliness and top speed. In this vehicle, the driver gains a feeling of safety and tranquillity, to which the smooth running of the engine, the ease of use and the excellent visibility of the vehicle particularly contribute.

This review of the DKW Schwebeklasse was published in the 23rd May 1936 edition of AAZ magazine, Nr 21. It was republished in the AUVC Nachrichten magazine in March 2005. The original copy is here: https://auvc-archive.blogspot.com/2020/02/auvc-nachrichten-vol-120-march-2005.html

Additional photos of the Schwebeklasse were sourced from Vorkriegs-Klassiker-Rundshau blog, which showcases a marvelous collection of photographs from pre-war Germany. It's well worth a visit. https://vorkriegs-klassiker-rundschau.blog/2021/01/02/kontrastprogramm-dkw-schwebeklasse-im-schnee/
1934 DKW Schwebeklasse brochure: https://dkwautounionproject.blogspot.com/2017/07/1934-dkw-schwebeklasse-brochure.html
1935 DKW Schwebeklasse Owners Manual: https://dkwautounionproject.blogspot.com/2022/06/1935-dkw-48-schwebeklasse-owner-manual.html



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