Considering its needs and capabilities, the Reichswehr already in 1926-27 had formed the requirements for promising armored vehicles. Among other samples, the army wanted to get a multi-wheeled armored car that can show high mobility in all conditions, to protect the crew from infantry weapons and attack the enemy using a cannon and machine gun. In this case, the car was supposed to be based on a specially designed chassis. The program to create such a combat vehicle was named Mannschafstransportwagen or MTW - “The vehicle for transporting personnel”.
Prototype BN-ZRW overcomes water barrier. Photo Aviarmor.net
Three leading companies of the German automotive industry were involved in the MTW program. Engineers from Büssing-NAG, Magirus and Daimler-Benz were supposed to work out and present their versions of a promising armored car that meets the requirements of the military. Soon the military showed the necessary documentation, which made it possible to draw the necessary preliminary conclusions and continue the work.
The designers of Magirus and Daimler-Benz suggested using original four-axle chassis capable of providing the required mobility. The engineers from Büssing-NAG went further - they developed a five-axle undercarriage, which was more long and gave some advantages. It should be noted that the number of wheels determined the name of the project. The armored car was designated as BN-ZRW - Büssing-NAG Zehnradwagen ("Ten-wheel machine").
Perspective armored car Büssing-NAG ZRW should have a recognizable appearance, directly related to the original design of the chassis. At the same time, it markedly differed from other developments of the MTW program. In particular, the authors of this project decided to abandon the curved parts and use a less complex body shape, which could to some extent simplify production.
An armored car of a new type was proposed to be built on the basis of a supporting hull, providing the required level of protection. The relatively thin armor was supposed to withstand the hit of bullets and fragments. It was proposed to assemble individual armor parts in a single design using rivets and welding. We used the layout of the case, which has proven itself in the field of tanks: the front part of the internal volumes was reserved for the control compartment, the fighting compartment was located in the center, and the power plant was located in the stern.
The body of the armored car from the "Bussing-NAG" had a fairly simple form. Over the entire length of the body had a cross section in the shape of the letter "T" with large side niches above the wheels. The forehead of the body consisted of several box elements. In this case, in the center of the upper frontal part there was an inclined section. Behind such a forehead were a horizontal roof and vertical sides. It is curious that the vertical lower parts of the sides, on which the undercarriage elements were mounted, had to be connected to the wheel-mounted niches with the help of several struts. Behind the hull had a curved stern leaf.
According to reports, the armored car of the new type had to carry a rotating turret with weapons. Its dome was supposed to have the shape of a truncated cone with a curved roof and a straightened portion of the forehead, having an embrasure of sufficient size. It should be noted that the tower for the BN-ZRW armored car remained on paper. An experienced armored car was not equipped with a full-fledged fighting compartment.
General view of the armored car in the complete set. Picture of the magazine "Armored collection"
At the rear of the hull was a gasoline engine. According to some reports, it was a Daimler-Benz M36 product with 100 horsepower, also used in other projects of the Mannschafstransportwagen program. The engine was connected to a mechanical transmission that distributed torque to all the wheels of the car. Power delivery to a separate propeller shaft was not envisaged. It was suggested to cross water barriers by swimming, but with the help of wheel rotation.
An original chassis with five pairs of large diameter wheels was developed. A spring suspension was used, the elastic elements being located between the hull side and the wheel. For certain reasons, the distance between the two front and two rear axles was less than the second and third gaps. The large length of the machine did not allow for the effective use of traditional “automobile” management methods. Because of this, driving along the course was suggested using a transmission - by changing the speed of rotation of the wheels of one of the sides.
The presence of an elongated chassis with a large number of wheels made it possible to somewhat increase the carrying capacity and structural strength. These advantages should be used in determining the composition of weapons. All the weapons of the Büssing-NAG BN-ZRW armored vehicle were to be placed in a rotary turret on a single unit with common vertical guidance drives. The use of separate mounts, as in the project Magirus M-ARW, was not provided.
The main weapon of the armored car was supposed to be a small-caliber gun. Considered the possibility of using the system caliber 20 or 37 mm. As a supplement to the gun should have used the MG 08 machine gun or other weapons with similar characteristics. Shells for guns and boxes with ribbons for the machine gun should be placed inside the crew compartment.
The crew included five people. The jobs of two crew members - the driver and his assistant - were located in front of the hull, in the control room. Access to this compartment was provided by hatches in the roof. For the observation it was proposed to use inspection hatches. The commander, gunner and loader had to work in the fighting compartment. Their places were under the dome of the tower and equipped with the necessary viewing devices.
As follows from the available data, the BN-ZRW armored car was significantly longer and heavier than the other two samples of the MTW program. The length of the machine could reach 8,5-9 m, the combat weight - not less than 8-9 t. At the same time, acceptable mobility indicators could be obtained. The speed on the highway would reach 50-60 km / h. Using the rotation of the wheels, the car was able to move through the water.
Experienced armored vehicle, view of the left side and the stern. Photo Kfzderwehrmacht.de
In 1929, Büssing-NAG, along with other participants in the Mannschafstransportwagen program, received permission to build a new type of prototype machine. Soon after, the assembly of the first BN-ZRW, which was intended for testing, was launched. The design of the combat vehicle used a new original chassis that needed verification. For this reason, the first prototype armored car had a specific design that did not fully comply with the project.
First of all, an experienced armored car was not equipped with a regular turret. Instead, a lightweight construction with glazing was placed above the hull of the hull. Before the jobs of the driver and his assistant installed a frame with glazing. A similar device was behind the epaulet. Between themselves, the glazing was connected by longitudinal handrails. Also, probably, inside the body was placed the ballast necessary to bring the mass of the machine to the required values. In the central part of the body could be located specialists who monitor the course of the tests.
In the same 1929, three prototypes, including the Büssing-NAG BN-ZRW in an incomplete set, were put to factory testing. A little later, after part of the inspections, a prototype from the firm Magirus received a turret with weapons and then was sent to the Kama tank school in the Soviet Union. Tests of armored cars DB-ARW and BN-ZRW, which did not have weapons, continued on German test sites.
As far as we know, a promising armored car from the company "Bussing-NAG" could not unequivocally establish itself. This machine - both in the proposed project and in the presented form - had certain positive features. At the same time, noticeable shortcomings were identified. As a result, the fate of the project was in question.
The five-axle chassis showed good characteristics of maneuverability and mobility in all studied landscapes. It was also confirmed the possibility of crossing water obstacles by swimming. The stated characteristics allowed to show the characteristics and capabilities, at least, no worse than other armored vehicles of the time.
Later, after installing the turret and weapons, the BN-ZRW armored car could demonstrate good combat capabilities. The water-cooled machine gun was a convenient means of dealing with infantry or unprotected equipment, and the 37-mm gun made it possible to hit a wide range of targets characteristic of the battlefield of that time.
Experimental chassis on trial. Photo Aviarmor.net
However, various difficulties arose during the tests. The presence of ten drive wheels with a fairly complex transmission, among other things used to control the course, has become a real problem. Aggregates of the advanced transmissions regularly broke down, demanding repair and delaying testing. Similar problems arose with the existing chassis. One can only guess how many failures were avoided due to the rejection of the steered wheels in favor of maneuvering due to the difference in speed.
The Büssing-NAG BN-ZRW machine, like the other armored vehicles of the MTW program, had not only technical drawbacks. One of the most serious problems was the cost. The vast majority of units and assemblies of an armored car had to be made from scratch, which led to an unacceptably high price of the finished sample. The future mass production made it possible to reduce to some extent the cost of an individual machine, but even in this case, the re-equipment was too expensive for the treasury.
Tests of a number of experienced armored vehicles, developed by three companies, lasted for several years. The purpose of the checks was to establish the real potential of the equipment in the context of the armament of the army, as well as the search for the most successful and effective technical solutions. Until a certain time, all three vehicles were considered as potential vehicles for the ground forces, but soon such plans were abandoned. Armored cars were unacceptably expensive to manufacture and too complex to operate, which was critical in light of Germany’s limited financial resources.
Nevertheless, the tests continued even after the military refused to accept the future adoption of the vehicles. Now several prototypes, including the only BN-ZRW without a tower, were used solely as a means of collecting the necessary information. The obtained data were supposed to be used to create new projects of similar technology.
Not later than 1931-32, the engineers and the military completed a study of an experienced Büssing-NAG armored car, after which they decided to stop the tests. The no longer needed prototype was sent to storage and soon dismantled for metal. The Reichswehr did not want to buy such equipment, and the developer did not need it either. Now an interesting sample of technology can be seen only in a few photographs.
The goal of the Mannschafstransportwagen / MTW program was to create a promising armored car that could accompany the infantry and support it with fire. Part of its main tasks was solved - the three German companies actually managed to create armored vehicles with the required characteristics. However, only one of them was able in practice to show their fighting and fire qualities. In addition, all the samples presented were distinguished by high complexity and a corresponding price. As a result, Büssing-NAG BN-ZRW, Magirus M-ARW and Daimler-Benz DB-ARW armored cars were not put into service. However, the experience gained in creating these projects was soon used in the development of the following German armored cars. And these machines, unlike their predecessors, were able to enter service.
Chamberlain P., Doyle H. Encyclopedia of German tanks of the Second World War II 1933-1945. AST / Astrel, M .: 2003.
Baryatinsky M. Wehrmacht Armored Vehicles. // armored collection. 2007. No.1.