Since 1939, German specialists have been working on remotely controlled equipment for the ground forces. The first example of such a system brought to mass production was the Sd. Kfz.300 minesweeper, created by the Borgward company. On the basis of general ideas and solutions, several machines were developed, one of which was built in the amount of 50 units. Also at that time, the possibility of creating a remotely controlled blasting machine was considered. For certain reasons, work on such a project began only in 1941. This project received the designation Sonderkraftfahrzeug 301.
The purpose of the new project, the development of which was entrusted to the company Borgward, was the creation of a relatively large armored vehicle with remote control, designed to transport an explosive charge. Even during the French campaign, German troops used vehicles of a similar purpose, such as the Landusleger I, built on the basis of the light tank Pz. Kpfw. I. Such a technique could deliver a relatively heavy charge of explosives to enemy fortifications, but it had a number of serious drawbacks. In the new project, it was required to get rid of all negative features and provide a full-fledged solution to the assigned tasks. The project of the new blasting machine received the official designation Sd. Kfz.301. It is also known as Gerät 690, Schwere Ladungstrager and Sonderschlepper B IV.
Museum machine Sd. Kfz.301 in Münster. Photo Wikimedia Commons
The developer was required to create a tracked vehicle capable of transporting small loads or transporting a special explosive charge to the installation site. In this regard, there were some specific requirements. So, the car had to be as simple as possible and be cheap to manufacture. In addition, it was required to provide control both from its own cabin (for moving on the march and when used as a vehicle), and using remote control from another machine. Such requirements led to the formation of an original design. It is noteworthy that in the new project Sd. Kfz.301 it was decided to use some of the developments from the previous Sd. Kfz.300.
Development of the blasting machine began in October 1941. By this time, a new tracked ammunition carrier Borgward B III was delivered to the series. In order to save time, effort and money, it was decided to build remotely controlled equipment on the basis of the existing conveyor. The latter "shared" with the new project the power plant, chassis and other units. At the same time, some of the components for the new vehicle had to be developed from scratch in view of the new tactical role.
First of all, a new specially shaped body was developed. A subversive charge of large mass and corresponding dimensions was proposed to be transported on the frontal sheet of the hull, in a special recess of the desired shape. For this reason, the front of the Sd. Kfz.301 hull had a characteristic shape with raised side parts and a recessed central part. In this case, all the details of the frontal part were located at an angle to the vertical, and their upper part at the same level converged with the roof.
Machine in the fields. The deckhouse is not used. Photo Aviarmor.net
Also, the hull received vertical sides and a horizontal roof. The feed consisted of several sheets at an angle to each other. In the front right part of the roof, four flaps were provided, mounted on hinges. If necessary, the driver could lift them, making a small wheelhouse, and thereby provide protection against some threats. In the stowed position and when using remote control, the wheelhouse flaps had to be placed on the roof of the hull and thereby reduce the overall height of the machine.
The frontal plates of the hull and deckhouse were 10 mm thick. The sides were proposed to be made from 5-mm sheets. The roof and bottom had to be 3-4 mm thick. With such protection parameters, the car could withstand hits from small arms bullets, and also not be afraid of fragments of artillery shells. At the same time, the maximum possible reduction in the cost of construction and operation was achieved.
The body of the Sd. Kfz.301 blasting machine was distinguished by its relatively small size, which is why a fairly dense layout of internal units and volumes was used. In the front of the hull, directly behind the frontal plates, the transmission units were placed. Behind them, at the starboard side, there was a small control compartment with a driver's workplace. The feed contained the engine, which was connected to the transmission using a propeller shaft.
Sd. Kfz.301 Ausf. A as an Allied trophy. Photo Aviarmor.net
The car received a Borgward 6M RTBV carburetor engine with a power of 49 hp. To transfer torque to the front drive wheels, a manual transmission with a single-speed gearbox was used.
The chassis included five double road wheels on each side. The rollers had individual torsion bar suspension. Due to the relatively low mass and low load on the suspension, it became possible to use short torsion bars and place them on one axis. In the front of the hull, with a noticeable excess over the rollers, there were drive wheels, in the stern - guides. A 205 mm wide track with tracks equipped with rubber pads was used.
It was proposed to control a new type of subversive vehicle using equipment at the driver's workplace or using a remote system. In the first case, the driver, using levers and pedals, could fully control the operation of the systems and the behavior of the machine. For remote control, the EP3 system was used, which provided control from a remote control. With the help of remote control, it was possible to start and stop the engine, control the movement of the car, as well as enter commands into the explosive charge and dump it.
The driver only uses the wheelhouse side flaps. Photo by Chamberlain P., Doyle H. "A Complete Guide to German Tanks and Self-Propelled Weapons of World War II"
The explosive charge for the Sd. Kfz.301 was a large metal container with the required amount of explosive, a fuse and other systems. In the transport position, a metal box with 500 kg of explosives was supposed to be located on the frontal sheet of the hull and go into its recess. When reaching the point where the charge was placed, the car had to open the locks, after which the container could slide down to the ground along the inclined frontal sheet. The detonator had the ability to set the time after which the detonation should have been made. In addition, a fuse was provided that did not allow the fuse to operate at a certain distance from the operator. It was possible to install a fuse at a distance of up to 900 m.
The first version of a new type of blasting machine had a length of 3.65 m, a width of 1.8 m and a height of 1.19 m. The combat weight with a 500-kg charge was determined at the level of 3.6 tons. The vehicle could reach speeds of up to 38 km / h and had a cruising range of more than 210 km. Remote control systems provided line-of-sight control of the vehicle.
The proposed way of using the new technique was as follows. Under the control of the driver, the Sd. Kfz.301 was supposed to arrive in the area of combat operations. Next, she was to be controlled by radio from a remote control installed on another armored vehicle. At the commands of the operator, the vehicle was supposed to go to the place where the explosive charge was installed, for example, to the enemy's long-term firing point. Having reached the target, the car had to drop a charge, ready to detonate, and go back. Next, an explosion was to occur, capable of destroying the enemy's fortification. Returning back, the blasting machine could receive a new container with a warhead.
Demolition car, rear view. Photo by Chamberlain P., Doyle H. "A Complete Guide to German Tanks and Self-Propelled Weapons of World War II"
It took several months to develop the Sd. Kfz.301 project. The construction of the first prototype of such equipment started at the beginning of 1942. Further, at one of the test sites, tests were carried out in which various features of the work of the new sample were checked. In particular, the control of regular bodies and with the help of a radio system was practiced. In general, the tests were successful, after which the new subversive vehicle was recommended for adoption.
In May 1942, Borgward began to fulfill an order for the construction of a new type of serial equipment. In view of modernization plans, the first version of the blasting machine received the updated designation Sd. Kfz.301 Ausf. A. Production of the "A" variant lasted a little over a year - until June 1943. During this time, 12 prototypes and 616 serial machines rolled off the assembly line. It should be noted that, starting with a certain series, the vehicle received additional booking. To improve protection, overhead armor plates with a thickness of 8 mm were used.
Serial blasting machines Sd. Kfz.301 Ausf. A were supplied to the troops and were used to a limited extent on the Eastern Front. Based on the experience of using such technology, the military compiled a list of necessary modifications to the design, which made it possible to increase the efficiency of its work. It was required to redesign the chassis and change the design of the hull. In addition, it was planned to introduce some other innovations.
Discharge charge. Photo by Chamberlain P., Doyle H. "A Complete Guide to German Tanks and Self-Propelled Weapons of World War II"
As part of the new project, designated Sd. Kfz.301 Ausd. B, it was proposed to slightly change the design of the hull. So, the thickness of the sides and stern was increased to 10 mm, which made it possible to somewhat increase the level of protection against small arms and shrapnel. In addition, the rubber pads were removed from the tracks, and the hinge that connected the tracks was redesigned. Finally, the EP3 remote control system has been upgraded.
Tests of the second modification of the blasting machine were completed in the early summer of 1943. In June, the assembly of the first production vehicles began. Until November 1943, 260 serial Sd. Kfz.301 Ausf. B were built. Like the vehicles of the first modification, vehicles with the letter "B" were sent to the front and used in various operations.
The first modifications of the Sonderkraftfahrzeug 301 blasting machines entered service and were mastered by the troops shortly before the start of the Battle of Kursk. This technique was the first to receive the 301st and 302nd tank battalions. During these battles, remotely controlled equipment was used to make passages in minefields, as well as to undermine fortifications. For some time, new special vehicles successfully coped with the assigned tasks and inflicted damage on the enemy. Nevertheless, in the future, the Red Army found ways to deal with the enemy novelty.
A blasting machine next to other equipment. Photo Aviarmor.net
It quickly became clear that the German remotely controlled vehicles did not have a powerful enough reservation, which is why they were "afraid" not only of artillery, but also of anti-tank rifles. In addition, the 5-mm armored sides of the hull could penetrate even 7, 62-mm armor-piercing bullets at distances of no more than 50-70 m. An additional disadvantage of the Sd. Kfz.301 was the short range of the remote control system. In some cases, the operator could lose visual contact with the machine with consequent consequences for the efficiency of its use.
Losses during the Battle of Kursk forced the German command to withdraw some of the blasting machines from the front line and send them to other missions. So, in 1944, Sd. Kfz.301 were actively used during the suppression of the Warsaw Uprising. A big problem for the German troops were the numerous barricades built by the rebels. Remotely controlled vehicles were used to demolish debris that hinder the movement of troops. Due to the limited firepower of the enemy, this use of technology was not associated with large losses.
The second result of losses in the first battles was an order for the development of another modification with improved armor. When developing the Sd. Kfz.301 Ausf. C project, it was required to significantly increase the protection of the vehicle, as well as make some other changes to its design, primarily related to the expected increase in weight.
Modification Sd. Kfz.301 Ausf. C. Photo by Chamberlain P., Doyle H. "A Complete Guide to German Tanks and Self-Propelled Weapons of World War II"
In the "C" modification, the blasting machine was to receive frontal and side plates 20 mm thick. Other hull parts were to be made of 6 mm armor. The driver's workplace has shifted to the port side. According to calculations, the combat mass of the updated equipment was supposed to reach 4850 kg. To compensate for the increase in weight, it was proposed to use a new engine with increased power. Now a Borgward 6B carburetor engine with a power of 78 hp was supposed to be located in the rear of the hull. Such a power plant made it possible not only to compensate for the increase in mass, but also to slightly increase the mobility of the machine. The maximum speed has increased to 40 km / h.
According to some reports, during the Sd. Kfz.301 Ausf. C project, it was planned to solve the problem of full control over the operation of the machine at a great distance. For this, it was proposed to use a television camera that transmits a signal to the operator's console. However, the technology of that time was not perfect, which is why such a project ended in failure. Production machines of the new type had to be monitored visually, using available optical instruments.
Sonderkraftfahrzeug 301 Ausf. C machines were produced from December 1943 to November 1944. During this time, Borgward was able to assemble and deliver 305 machines to the customer. The equipment was again sent to the customer in the person of the armies. Thus, from 1942 to 1944, slightly less than 1200 armored vehicles of three modifications were built. Some of this technique was used in battles, while others met the end of the war at temporary storage sites.
Sd. Kfz.301 Ausf. A at the Vienna Museum. Photo Avstrija.at
It should be recalled that the requirements for the Sd. Kfz.301 project emphasized the need to reduce the cost of production, which was believed to reduce the economic consequences of equipment losses. As it turned out later, this approach was fully justified. According to reports, by March 1, 1945, the German army had only 397 blasting machines of three modifications out of 1200 built. At the same time, only 79 vehicles were operated in the army units, and the remaining 318 were in storage and were waiting in the wings. Thus, a total of two-thirds of the vehicles were lost under various circumstances.
It should be noted that the losses of blasting machines were associated not only with their destruction. For example, in January 1945, the advancing Red Army managed to capture a large number of various German military equipment loaded on railway platforms, but never evacuated. Among the trophies were a number of Sd. Kfz.301 vehicles.
In the last months of the war in Europe, the German military made an attempt to use the existing remotely controlled vehicles as "manned" carriers of anti-tank weapons. By the spring of 1945, just over fifty Sd. Kfz.301 received new weapons, which allowed them to participate in the ongoing battles in a new role. However, such machines, collectively known as the Wanze, could not have a noticeable impact on the course and outcome of the war.
The Red Army soldiers are studying the Wanze self-propelled gun based on the Sd. Kfz.301. Photo Armourbook.com
Remotely controlled armored vehicles of the Sd. Kfz.301 family of three modifications have been used by German troops with varying success for several years. This technique made it possible to solve the assigned combat missions, but it suffered serious losses and quickly went out of order under enemy fire. As a result, the efficiency of the work was constantly decreasing, and the losses were increasing. Attempts to give technology a new role, undertaken at the end of the war, were also unsuccessful.
By the time of the surrender of Nazi Germany, the troops had no more than 350-400 Sonderkraftfahrzeug 301 blasting machines in different versions. All this equipment later became a trophy of the allies. The overwhelming majority of such cars in the post-war period went for recycling. For display in museums, only a few copies of varying degrees of preservation have been preserved. One of them is on display at the armored museum in the Russian Kubinka.
