The essence of the German strategy "blitzkrieg" was the rapid breakthroughs of mechanized formations in the weak spots of the enemy's defenses. The Nazis preferred not to attack especially fortified objects head-on, but to bypass them and, taking them in a ring, to destroy them. One of these defense systems, which in the future had to be bypassed and then destroyed, was the French Maginot Line. Initially, it was planned to use field artillery to attack the fortifications, but later the idea of a heavy self-propelled artillery installation arose. The results of the Polish company of the Wehrmacht fully confirmed the need for such equipment and its good prospects.
Immediately after the end of the capture of Poland, the leadership of the German army issued a technical assignment for the creation of a new self-propelled artillery unit armed with a gun with a caliber of at least 100 mm. Within a few weeks, the weapon for the self-propelled gun was chosen - the 10.5 cm Kanone 18 L / 52 cannon - and the project developer. The last was the company "Krupp". At this stage, the self-propelled gun was named 10.5 cm K gepanzerte Schartenbrecher (105-mm self-propelled anti-bunker gun). Work on the project did not go too fast. For various reasons, primarily related to the power of the gun, the design of the new ACS was delayed. As a result, even prototypes of self-propelled guns, which received the unofficial nickname Dicker Max ("Fat Max"), did not manage to get into the war with France. Nevertheless, the absence of the need to attack objects of the Maginot Line had almost no effect on the state of the project. The only change associated with the defeat of France was to change the purpose of the self-propelled gun. Now "Fat Max" was not an anti-bunker self-propelled gun, but a tank destroyer. Considering the booking of most European tanks that served in 1940, it is not difficult to imagine the consequences of their shelling from a 105-mm cannon. At the same time, the project was renamed 10.5 cm K gepanzerte Selbstfahrlafette (105 mm armored self-propelled gun).
The PzKpfw IV Ausf. A. medium tank was chosen as the basis for the Dicker Max self-propelled gun. The chassis of the tank was powered by a 6-cylinder Maybach HL66P engine with 180 hp. With an estimated combat weight of 22 tons, the new ACS was supposed to have a specific power at the level of 8-8, 5 hp. per ton. These parameters were enough to achieve a speed of 25-27 km / h on the highway. For a tank of those times, this was clearly not enough, but a self-propelled gun mount with a 105-mm gun could have such a speed. The armor of the vehicle's hull remained the same - frontal armor of 50 mm and sides of 20. Instead of the original turret of the PzKpfw IV tank, an armored wheelhouse was installed. Moreover, its dimensions were much larger than that of the original tower. For the convenience of accommodating a crew of five, the wheelhouse occupied the entire upper part of the hull, from the middle to the stern. Another design feature, also related to the crew, was the absence of a wheelhouse roof. Of course, this way the crew did not have protection from air attacks, but they did not need to huddle in a small box closed on all sides. Over time, the project has been slightly improved. In particular, the engine and transmission were replaced. With the Maybach HL120TRM engine (300 hp), the maximum speed of the car increased to 40 km / h.
A 105 mm K18 L / 52 cannon was installed in the wheelhouse. The dimensions of the internal volumes of the cabin led to a limitation in the pickup angles of 8 ° in both directions horizontally and from -15 ° to + 10 ° in the vertical plane. The ammunition load of the gun was 26 shells, placed in a stowage under the side walls of the wheelhouse. On trial firing, the K18 L / 52 cannon showed remarkable results for that time. From a distance of two kilometers, it pierced just over 100 millimeters of armor steel. Such indicators of armor penetration, in fact, became the reason that the protection of the self-propelled gun was not the best, and the fighting compartment was not equipped with a roof. As an additional weapon for self-defense, the crew was supposed to have three MP-40 submachine guns with a total ammunition of 576 rounds. A little later, the composition of additional weapons was slightly revised towards improvement.
While German tank wedges bypassed the Maginot Line, destroyed fortifications in France and served for the benefit of the Third Reich, a new self-propelled gun, designed to help them, was just beginning to prepare for production. As a result, the first two prototypes were ready in January 1941. Soon they were sent for testing. Field trips and firing demonstrated the high potential of the self-propelled gun: all problems with armor and mobility were more than compensated for by firepower. However, questions were raised by the chassis. To ensure normal operation with a large-caliber gun, it had to be modified. For this purpose, on the basis of the PzKpfw IV and PzKpfw III running gear, a new system was created that had sufficient characteristics. But the "hybrid" origin of the new suspension entailed a lot of "childhood illnesses". In the future, the 10.5 cm K gepanzerte Selbstfahrlafette was planned to be equipped with a new improved tracked propulsion unit. It was this chassis that was going to be installed on production cars. Speaking of serial production, already by the beginning of the tests, the Krupp leadership, together with the Wehrmacht, were considering the issue of starting the full-scale construction of the Fat Maxs. As of the end of spring, the first months of 1942 were considered as the start date for serial production.
A few days before the attack on the Soviet Union, both prototypes of the new self-propelled guns were transferred to the troops for trial operation. The vehicles were attached to the anti-tank battalion Panzerjager Abteilung 521. The first battles with the participation of Dicker Max demonstrated not only the anti-tank potential of the vehicles, but also their versatility - the 105-mm gun made it possible to effectively fight fortifications. However, just a few weeks after the start of military use, one of the experienced self-propelled guns was lost in an accident. Accidental fire in the fighting compartment led to detonation of the ammunition load and subsequent serious damage to the vehicle. According to reports, the wreckage of the self-propelled gun soon fell into the possession of the Soviet Union. The second prototype served until the fall of 1941, received a number of damages, but was still suitable for use. Nevertheless, the remaining SPG was sent to the factory for repairs in October. The restoration and modernization took several months and the last "Fat Max" returned to the front in time for the start of the summer offensive of the German troops. It was at this time that the self-propelled power plant was updated, and for self-defense it received an MG-34 machine gun with 600 rounds of ammunition.
Self-propelled guns 10.5 cm K gepanzerte Selbstfahrlafette have earned a good reputation among the troops. The gun was effective both against bunkers and against all types of Soviet tanks. In addition, fragmentation ammunition made it possible to fire on clusters of manpower. However, the Dicker Max had one tactical flaw. Even two vehicles were clearly not enough for the normal combat operation of the 521st anti-tank battalion. Several dozen self-propelled guns were required. According to some soldiers, these vehicles must advance in close formation. Also, complaints were caused by the weak Maybach HL66P engine, which was subsequently replaced. Its 180 horsepower was not enough to keep up with the troops on the march. Moreover, more than once self-propelled guns got stuck off-road, including in battle. Finally, there were serious problems with direct fire. Due to the presence of a muzzle brake on the gun, a cloud of dust rose when fired. It interfered with aiming and required the involvement of additional gunners located at a distance from the self-propelled gun.
Throughout the second half of 1942, at meetings in the German leadership, the topic of fine-tuning the "Fat Max" and the launch of mass production came up every now and then. But, fortunately for the Red Army, it all ended in talk. Due to the need to correct the mass of design problems and the workload of the Krupp company, only two SPGs were made, one of which was lost, and the second was recalled to the plant in the middle of the 42nd. According to various sources, the remaining prototype was dismantled, or survived until the end of the war, when it was destroyed by Allied bombers.
This is how the Dicker Max self-propelled gun will look in the game World of Tanks
