A Story About the German Remote-Controlled Engineering Vehicle “Mittlerer Ladungsträger” (Sd.Kfz.304) Springer
World War I spurred a major leap forward in the development of a wide variety of military technology. Some of the designs that appeared on the battlefields were intended to overcome the challenges of trench warfare. One such innovation was remotely controlled vehicles, which essentially functioned as self-propelled mines. Although they were never actually deployed, the idea itself proved compelling. However, the ideas of the French—who were the first to develop such combat vehicles—were fully (and much later) exploited by their adversaries, the Germans.
kl.Kettenkw. (f.g), Springer’s direct predecessor
The first combat-ready remotely controlled engineering vehicles were developed in Germany in 1940. However, both the Minenräumwagen Borgward B I mine sweeper and the Minenräumwagen Borgward B II demolition vehicle that followed it proved to be unsuccessful designs. The Sd.Kfz.301 (Borgward B IV) remotely controlled engineering vehicle was more successful, but it proved to be far too expensive. The self-propelled mine Sd.Kfz.302 (Goliath) was much cheaper, but it carried only a small amount of explosives. As a result, a third, intermediate self-propelled mine was developed—the mittlerer Ladungsträger (Sd.Kfz.304) Springer.
The first prototype of the machine, currently a 5-roller model
The development of this combat vehicle was preceded by experience with a similar vehicle. In the spring of 1942, NSU produced a prototype of the self-propelled mine kl.Kettenkw. (f.g). In fact, it was a semi-tracked HK-101 (Kettenkrad) tractor that had been converted into an explosive carrier. A box containing 300 kg of explosives was installed in place of the rear seats. Similar to the larger Borgward B IV, the vehicle was driven by a driver over long distances; thereafter, it was guided into battle via radio using a special command tank, the Pz.Kpfw.III (funk).
5th, now a 6-roller prototype
A total of two variants of the kl.Kettenkw. (f.g) were produced, which were tested in combat by the 300th Radio-Controlled Tank Battalion (Pz.Abt.300(F.L.)). They were deployed in Crimea, though the results of their use were mixed. On the one hand, the very idea of a relatively inexpensive vehicle (the Kettenkrad’s price tag was about one-fifth that of the Borgward B IV, plus modifications) capable of hauling 300 kg of explosives seemed appealing. On the other hand, in this form, the self-propelled mine was clearly unsuitable. Something lower to the ground, simpler, and with minimal armor protection was needed.
The 8th prototype vehicle is now equipped with onboard displays
A contract to develop a self-propelled mine using HK-101 units was signed with NSU Motorenwerke in early 1943. The immediate start of mass production was preceded by the creation of a series of prototypes. According to correspondence, 16 prototype vehicles had been manufactured by September 15, 1943. The first of these were essentially test beds for exploring new ideas. As a result, they differed significantly from the vehicles produced later. The first prototype, nicknamed “Springer,” had a 5-wheel chassis. It was later decided to lengthen the chassis, and the vehicle became a 6-wheeler.
Off-Road Performance Tests
The main components of the HK-101 remained in place, which significantly accelerated the potential launch of the Springer into production. As with the Kettenkrad, the vehicle was powered by a 1.5-liter Opel Olympia engine—mass-produced and simple. Naturally, the Kettenkrad was not suitable in its original form; the “chassis” itself was built from scratch. Now the driver-mechanic sat in the rear, like on a tractor, while the engine and the compartment for explosives were located in the front. The first prototype also had a cooling system at the front, but it was later moved to the rear, behind the driver.
This is what the production models of the Sd.Kfz.304 looked like
The Springer armored hull did not take shape immediately, although the overall concept was exactly what the customer wanted from the start. The total height was 1.45 meters, including the hinged panels needed to protect the driver. Without them, the vehicle’s height was just over one meter. As required by the customer, the hull was fitted with armor up to 10 mm thick. Starting with the 8th prototype, side screens were installed to protect the sides. Thus, the self-propelled mine had quite adequate protection against bullets. It could only be penetrated by a rifle bullet at close range.
A total of 500 units were planned to be produced
Like the Borgward B IV, this vehicle—known as a medium explosive carrier—boasted quite decent mobility. The armor and 330 kg of explosives certainly increased its combat weight (to 2.4 metric tons) and reduced its top speed, but 42 km/h was quite sufficient. In combat conditions, the vehicle was controlled by radio, with converted StuG 40 Ausf.G serving as mobile command posts. They replaced the Pz.Kpfw.III (funk) in the troops. The communication range reached 2 kilometers; however, visual contact was not possible at greater distances (and in reality, not much could be seen even from 1.5 kilometers away).
In combat configuration, the control compartment’s armor is folded up
Prototypes of the Springer underwent military trials in the spring and summer of 1943. On July 8, 1943, Heinz Guderian, who was Inspector General of the Panzer Forces at the time, ordered the vehicle to go into mass production. It was officially designated as the mittlerer Ladungsträger, and was also given the model number Sd.Kfz.304. A total of 500 such self-propelled mines were to be ordered; they occupied an intermediate position between the Sd.Kfz.301 and the Sd.Kfz.302/303. Due to its impressive explosive charge, the Sd.Kfz.304’s detonation caused a continuous chain reaction among mines within a radius of about 20 meters.
Like the Kettenkrad, it was steered using a handlebar
The main problem facing the Sd.Kfz.304 stemmed from shifting priorities and the situation at the front. Self-propelled mines were needed primarily for assault operations, preferably in the context of general positional warfare. However, starting in the summer of 1943, the German army was, for the most part, retreating rather than advancing. Of course, German war films showed the successful use of self-propelled mines against tanks, but a testing ground is one thing, and the actual battlefield is quite another. The fact that the situation was changing is evident from the fact that the contract to produce 1,000 Borgward B IVc vehicles was first reduced to 400 and then to 322. As for the Sd.Kfz.304, production of these self-propelled mines was initially postponed until May 1, 1945.
In fact, only 50 vehicles were delivered, and they saw almost no combat action
Subsequently, the contract for the production of 500 Sd.Kfz.304s was slightly revised. It was reduced to just 50 vehicles, of which 9 were delivered in October 1944, 16 in November, 10 in December, 9 in January 1945, and 6 in February. Notably, there is no mention whatsoever of any production run starting May 1, 1945, in the plans. And the Borwgard B IV c also disappeared from the plans for 1945. The plans list only the Sd.Kfz.303 self-propelled mines, equipped with internal combustion engines. Thus, they abandoned the expensive explosive carriers. Especially since NSU was being asked to produce more and more Kettenkrads, which were more useful than a single-use vehicle.
There are almost no photos from the front; Springer is usually seen in postwar photos
Under the circumstances, the Springer’s combat deployment didn’t really work out either. Of course, the new vehicle was added to the K.St.N.117f roster effective October 1, 1944. The vehicles were supposed to operate alongside the Sd.Kfz.301. But in reality, the situation on the front lines was such that, at best, Pz.Abt.301 (F.L.) could operate with them—and even that is not certain. Most of the “jumpers” were simply abandoned and captured by Allied forces. Two examples of the vehicle are currently known; of these, the one on display at Bovington is the most accessible.
They appeared too late, when the need for breakthrough capabilities had disappeared
If we consider the Springer as a self-propelled mine, it was perhaps the most successful model of its kind. It carried a very respectable amount of explosives, was significantly cheaper than the Borgward B IV, was better suited for mass production, and possessed decent mobility. The only problem was that it appeared too late. By the summer of 1943, such combat vehicles were no longer particularly relevant for use. As mentioned above, they proved useful in offensive operations, especially in the context of positional warfare. The changing situation at the front rendered them obsolete.
List of Sources:
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- US NARA
- Panzer Tracts No. 14: Armored Engineer Vehicles, Thomas L. Jentz, Hilary Louis Doyle, Darlington Publications, 1998
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