This plan was initiated due to the fact that airborne divisions made use of relatively light artillery pieces, such as the Škoda 7.5cm Gebirgskanone 15/28 mountain guns (weighing 716 kg), the 2cm Flak 30/38 anti-aircraft guns (750 kg), and even the 3.7cm Pak 36 anti-tank guns (440 kg), all of which could be transported in gliders and, above all, in the famed Junkers JU-52/3m aircraft – with the obvious drawback that, once on the ground, they relied on horses, dogs, mules, or soldiers for mobility. Tactical use was therefore very limited, as the lack of mobility negated much of the operational advantage of paratrooper forces.
As a solution, engineers at NSU proposed a compact tracked tractor (three metres in length and one metre wide), weighing just 1,280 kg. Internally designated the HK 101, this model was based on designs by NSU engineer Heinrich Kniepkamp, who had applied for a patent in June 1939 for a forestry tractor capable of towing loads over difficult terrain (the designation “HK” being an acronym for Heinrich Kniepkamp).
In terms of powertrain, it used a four-cylinder, 1,500cc engine from the Opel Olympia, producing 36 hp. This was sufficient to tow the aforementioned artillery pieces, while being small enough to fit through the side doors of the JU-52. A single front wheel made driving easier and reduced overall length. When necessary, the wheel could be removed quickly, reducing speed but enhancing off-road performance. The driver’s manual even recommended removing the wheel when crossing deep mud or rocky ground. With a top speed of 70 km/h, the Sd.Kfz. 2 Kettenkraftrad (literally “chain motorcycle”) was the fastest tracked vehicle of the Second World War.
The Kettenkrad (as it was also known in shortened form) first saw combat in 1941 during the invasion of Crete. While initially used primarily as an artillery tractor by the Luftwaffe’s Fallschirmjäger (paratroopers), it soon found its way into units of both the Waffen-SS and the Wehrmacht (including the Afrika Korps), not only as a towing vehicle but also for communications work (such as laying cable), delivering ammunition and supplies, and operating in terrain that most other vehicles could not traverse. Toward the end of the war, owing to its low fuel consumption and high towing capacity, the Kettenkrad was also used by the Luftwaffe to tow jet aircraft such as the Messerschmitt ME-262 and Arado Ar 234.
Virtually all examples captured by the Allies were quickly repurposed for their own use, typically repainted green with white stars added to the sides.
A total of 8,345 units were built, with production split between NSU Motorenwerke in Neckarsulm and, from 1943 onwards, Stoewer of Stettin. A third industrial facility – the Simca factory in Nanterre, France – supplied components for the model, although it did not assemble complete vehicles.
Originally painted dark grey, from February 1943 onwards the Sd.Kfz. 2 left the factory in desert yellow, and soon after this the vehicles no longer bore licence plates, unit markings, or even the standard 13cm-diameter front headlamp, retaining only the Notek blackout light for night operations. (Notek was an acronym for Nova-Technik GmbH, the Munich-based company that supplied low-visibility lighting for most German military vehicles.)
Rather surprisingly, production of the Kettenkrad resumed after the war – now for the original purpose envisioned by engineer Heinrich Kniepkamp. In 1946, NSU was contracted by the German Forest and Land Authority to reopen the production line. There was a need for small off-road-capable vehicles to operate in German forests.
The Sd.Kfz. 2 was henceforth referred to as the Waldschlepper (forest tractor), and customers included farmers, foresters, and vineyard workers. Production continued until 1949, with around 550 units built. The only visible difference from the wartime Kettenkrad was the replacement of the military Notek headlamp on the front mudguard with a standard civilian headlamp fitted in the same location. Most of these Waldschlepper were finished in dark green with some parts in desert yellow – both colours previously used in the camouflage schemes of the military version. Many had the word Waldschlepper stencilled on the sides of the fuel tank.
More intriguingly still, in 1957, at the request of the Bundeswehr (Armed Forces of the Federal Republic of Germany), NSU developed a modernised and slightly larger version known as the Gebirgskarette (mountain version). The new model replaced the Opel engine with a Porsche flat-four, promising even better performance. However, the project was ultimately cancelled and only three prototypes were built.