The twenties and thirties of the last century became a period of active development of armored vehicles. Engineers from different countries studied different layouts and applied different technical solutions, which led to the emergence of original and sometimes even strange designs. However, it was the experimental armored vehicles of that time that helped different states create their own schools of tank building. At the very end of the twenties, Sweden joined the countries engaged in the creation of their own tanks. Swedish tank building has a very interesting history. First of all, for the reason that it "comes" from German. The first Swedish tanks of their own construction (L-5) were developed in Germany. In addition, several of the following Swedish tanks were developed on the basis of this German project. In the future, the development paths of tank building in Germany and Sweden diverged. The first Swedish tanks of the twenties and thirties are of great interest. Let's consider several projects of that time.
Landsverk L-5
The first Swedish tank of its own production (but not development) was the Landsverk L-5 combat vehicle, also known as Stridsvagn L-5, GFK and M28. This tank was designed in Germany, and the Swedish company Landsverk was involved in the project as a prototype builder. In the mid-twenties, when the L-5 tank was being created, the German authorities tried to hide all projects of military equipment, which is why foreign organizations were involved in the creation of a promising light tank.
The GFK project (this is the name it bore in Germany) is believed to have appeared under the influence of English ideas of the early twenties. Seeing the latest foreign technology, the German military and designers began to develop several projects of similar machines at once. It is worth noting that only one of them, created under the leadership of designer O. Merker, reached the stage of testing the prototype. For obvious reasons, there were no major innovations in the GFK project, with the exception of a few original ideas. This light tank used a number of well-known and mastered by that time technical solutions, which could provide a comparative ease of production of equipment at enterprises of third countries that do not have their own tank building.
Perhaps the most interesting feature of the GFK / L-5 project was the original chassis. The tracks of that time had a small resource, which is why German engineers decided to equip the new combat vehicle with a combined wheeled-tracked chassis. Directly on the sides of the tank, a multi-roller tracked propeller with a front guide and rear driving wheel was attached. In addition, on the sides of the hull, next to the caterpillar, the suspension of the wheels with a system for lifting them was provided. The engine torque was transmitted through separate transmission units to the wheels. The gearbox and the driving rear wheels were connected using a chain drive.
It was assumed that the new GFK tank would be able to move on roads on wheels and switch to tracks before fighting on rough terrain. Such an opportunity could provide a promising tank with high mobility in combat conditions and at the same time did not lead to an increased consumption of an already small track resource.
We can say that the combined propulsion unit turned out to be the only truly original idea in the GFK / L-5 project. All other components and assemblies of the new tank were made in accordance with the usual technologies for that time. The hull was proposed to be assembled by riveting from relatively thin sheets of bulletproof armor. The layout of the internal volumes was carried out according to the classical scheme: in the front part of the hull, a control compartment with a workplace of a driver was placed. A fighting compartment with a rotating turret was placed behind it, and the hull stern was allocated for the engine and transmission. For the convenience of the driver's work, a small wheelhouse with viewing slots was provided above his workplace. The control compartment was moved to the starboard side. The left housed a separate armored wheelhouse with an MG 08 machine gun of 7, 92 mm caliber.
The main armament of the GFK tank was housed in a rotating turret. It consisted of one 37 mm cannon and one MG 08 machine gun. Like some other tanks of that time, the new German vehicle did not have coaxial weapons. The cannon and the turret machine gun were mounted on separate supports and, because of this, had different aiming angles. So, the gun could be aimed vertically within the range from -10 ° to + 30 ° from the horizontal. The vertical aiming angles of the machine gun were greater: from -5 ° to + 77 °. The rotating mechanisms of the tower allowed attacking targets in any direction. Inside the fighting compartment, it was possible to place 200 shells for a 37-mm cannon and 1000 cartridges for a turret machine gun. Another 1000 rounds were intended for the course machine gun in the front of the hull.
Like some other light tanks of the twenties, the GFK received two sets of controls. One of them was located in the driver's workplace, and the other in the rear of the fighting compartment. It was assumed that the second driver would provide greater maneuverability, and, if necessary, would be able to withdraw the damaged vehicle from the battlefield. It was not possible to find out how justified such a decision was. The only confirmed consequence of the use of two driver's seats was the tightness within the habitable volumes. The tank's crew consisted of four people: two driver mechanics, a commander and a machine gunner. It was assumed that a "free" driver-mechanic would be able to help other crew members in preparing the gun for firing.
The GFK tank turned out to be relatively small and light. With a length of about 5 meters, a width of about 2 m and a height of no more than 1.5 meters, the vehicle had a combat weight of about 7 tons.
By the time the design was completed, the German light tank received a new designation - Räder-Raupen Kampfwagen M28. The Versailles Peace Treaty did not allow Germany to build, test and use tanks. Because of this, German tank builders had to turn to foreign organizations for help. It should be noted that the German military did not want to risk and therefore delayed the decision for a long time. As a result, it was decided to build an experimental batch of six light armored vehicles.
The Swedish company Landsverk was involved in the further implementation of the M28 project. She was given the project documentation and instructed to build prototypes of the new tank. Apparently, to maintain secrecy, Swedish industrialists renamed the M28 project to L-5. It was under this name that he later became widely known.
In 1929, Landsverk built the first of the prototype armored vehicles. In the 30th, the assembly of the remaining five was completed. Six prototype tanks differed from each other in some design features. So, the first three tanks received a four-cylinder carburetor engine from Daimler-Benz with a capacity of 60 hp. The remaining three cars were equipped with 70 hp Bussing-NAG D7 gasoline engines. During the tests, it was supposed to compare the capabilities of the tank with different power plants. In addition, it was planned to compare the electric and hydraulic wheel lifting systems. The first four prototypes received electric, the fifth and sixth - hydraulic.
Shortly after construction was completed, testing of six prototype tanks began. At this stage, the project again became the subject of international cooperation. The fact is that five L-5 tanks were tested in Sweden. The sixth, in turn, went to the Soviet Union, to the Kama tank school in Kazan, where German tank crews were being trained at that time. Despite the tests carried out at different proving grounds, the responses of the German test tankers were generally similar. With acceptable firepower and a sufficient level of protection, the L-5 tank had ambiguous performance characteristics. The wheel lifting system turned out to be too complex, and its placement outside the armored hull negatively affected survivability in combat conditions.
Since the GFK / M28 / L-5 tank did not have any advantages over other armored vehicles of German design, work on it was stopped. In 1933, an experienced tank tested in Kazan was sent back to Sweden. The further fate of the six prototypes is unknown. Most likely, they remained at the Landsverk plant, where they were later dismantled. There are no reliable data on this score.
Landsverk L-30
Soon after receiving the design documentation for the M28 / L-5 tank, Swedish designers from Landsverk decided to create their own project of a combat vehicle for a similar purpose. After discussing the prospects for such a technique, it was decided to develop two tanks at once on the L-5 base. One of them was supposed to be an improved version of the German project with a combined chassis, and the second was supposed to be equipped with only a tracked propeller. These projects were designated L-30 and L-10, respectively.
Landsverk L-10
Landsverk L-30
Improvement work on the German project did not take much time. The design of the L-30 wheeled-tracked tank lasted only a few months. In 1930, Landsverk employees managed to create a technical project, and then build the first and, as it later turned out, the only copy of the new tank.
In its basic features, the L-30 light tank was similar to its predecessor, however, when creating the project, the Swedish engineers took into account the revealed shortcomings of the latter. Therefore, the design of the machine has undergone significant changes. The hull layout remained the same: the control compartment in the front, the combat compartment in the middle and the engine-transmission compartment in the aft. The driver's workplace on the L-30 tank, in contrast to the L-5, was located at the left side. In addition, the crew was reduced to three people, since it was decided to abandon the second driver's seat, which did not give any special advantages.
The armored hull of the L-30 light tank was supposed to be welded from rolled armor plates. The frontal hull had a thickness of 14 mm, the rest - up to 6 mm. It should be noted that in the manufacture of the hull of the prototype tank, the Swedish industrialists decided to save money and assembled it from ordinary steel. Nevertheless, this did not prevent the tests and conclusions from being drawn.
A 12-cylinder Maybach DSO8 petrol engine with a capacity of 150 hp was placed in the aft part of the hull. Next to it was a transmission designed to transmit torque to both propulsion units.
The undercarriage was the weakest point of the M28 / L-5 project. Despite all the advantages, the combination of tracked and wheeled propellers was not reliable enough. Landsverk designers took into account the experience of their German colleagues and created their own version of the combined chassis. First of all, they simplified the tracked chassis and thereby increased its reliability. Four road wheels remained on each side of the tank. They were interlocked in pairs and equipped with leaf springs. In addition, the tracked undercarriage included two carrier rollers, a front idler and a rear drive wheel.
The wheeled chassis of the L-30 tank was generally based on German developments, but there were several innovations in its design. So, the attachment points for the wheeled propeller were located on the side of the tank, above the road wheels and under the upper branch of the caterpillar. Four wheels with pneumatic tires are equipped with vertical spring suspension. The mechanism for lowering and lifting the wheels, according to some sources, had an electric drive. When driving on wheels, only the rear axle was driving.
All the armament of the L-30 tank was in the turret. The prototype received a 37 mm Bofors rifled cannon and a 7, 92 mm machine gun paired with it. The design of the conical tower made it possible to further change the composition of the tank's armament by installing a suitable weapon or machine gun of a different model on it. In addition, some sources mention the possibility of installing an additional machine gun in the front of the hull, next to the driver's workplace. Inside the fighting compartment, it was possible to place stowages for 100 shells for the cannon and 3000 rounds for the machine gun.
The tank of its own Swedish design turned out to be noticeably larger and heavier than the German prototype. Thus, the combat weight of the L-30 vehicle exceeded 11,650 kg. The dimensions of the new combat vehicle are of some interest. The Swedish-made tank turned out to be slightly longer than the German one (total length 5180 mm) and much higher - its height on the turret roof reached 2200 mm. Due to the change in a large number of elements of the undercarriage, the L-30 tank turned out to be about 60 cm wider than the L-5.
Tests of the experimental Landsverk L-30 tank started at the very end of 1930. The updated chassis clearly demonstrated its high performance. When using tracks, the tank moved on the highway at a speed of up to 35 km / h, and on wheels it accelerated to 77 km / h. The power reserve reached 200 kilometers. Such characteristics of mobility were high enough for the very beginning of the thirties. Nevertheless, the Swedish military commission had complaints about the new combat vehicle. The use of a tracked and wheeled mover complicated the design, and also negatively affected the simplicity and ease of use.
The further fate of the L-30 project was determined by comparison with another tank based on the German L-5 - L-10. The wheeled-tracked armored vehicle surpassed it only in speed on the highway when driving on wheels. Comparison of other characteristics either did not show any advantages of the L-30 tank, or it was not in its favor. As a result, the Landsverk L-10 tank was adopted by the Swedish army, which received the new designation Strv m / 31.
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The L-30 project proved to be the last Swedish attempt to create a light tank, the chassis of which could combine all the best aspects of tracks and wheels. Tests of seven armored vehicles of two models showed not only the advantages of the applied technical solutions, but also their serious disadvantages. Some problems of the L-5 tank were corrected in the L-30 project, but this did not lead to the appearance of equipment suitable for practical use. The general architecture of the wheeled-tracked undercarriage was too complicated to manufacture and operate, and also did not give tangible advantages over tracked or wheeled vehicles. Further development of the Swedish tank building went along the path of creating purely tracked vehicles, and the light tank L-10, created on the basis of the L-5, in one way or another became the basis for several of the following types of armored vehicles.
