The last capitalist we hang shall be the one who sold us the rope.
Karl Marx
In the late 1920s, Mikhail Tukhachevsky and other Red Army theorists envisioned that large numbers of medium and heavy tanks would be necessary in order to prevail in the next war, which was expected to be fought against a coalition of Western capitalist states. At the time, the only modern heavy tank in existence was the British multi-turreted, 34-ton2 Vickers A1E1 Independent, which impressed Tukhachevsky who regarded it as the template for a Soviet heavy tank. In July 1929, the State Defense Committee authorized construction of several new types of tanks, including a heavy tank. In order to meet this objective, an experimental tank design bureau known as OKMO (Opytniy Konstruktorsko-Mekhanicheskiy Otdel) was set up in Leningrad’s Voroshilov Factory (Zavod 174) in 1930 under the leadership of Nikolay V. Barykov. Leningrad’s Kirov Factory (Zavod 100) also established a tank design bureau. However, no Soviet engineers had any practical experience in designing large armored vehicles, so foreign expertise was necessary to jump-start the Soviet heavy tank project. When Eduard Grotte’s small team of German engineers arrived in Leningrad in March 1930, he was given the lead in developing the heavy tank, while Barykov looked over his shoulder. Tukhachevsky envisioned a small number of invulnerable, heavy tanks to lead breakthrough attacks, with technical capabilities akin to those of the Vickers A1E1 Independent.
Presiding over Soviet tank development was the State Defense Committee, headed by People’s Commissar Kliment Voroshilov, one of Stalin’s closest and most servile cronies. Stalin himself tended to get involved in critical weapons decisions, although he lacked a head for technical issues. Requirements for tanks were written by the Red Army’s Office of Mechanization and Motorization (UMM), which was created in 1929 to develop tanks, as well as train and organize all mechanized forces. From 1929 to 1936, the UMM was headed by Innocent A. Khalepsky, followed by Dmitry G. Pavlov from 1937 to 1940, both of whom influenced Soviet heavy tank development.3 Khalepsky drafted a requirement for a 60-ton tank mounting two 76.2mm guns, one 37mm gun and six machine guns. Early Soviet armor officers, like those in other countries, believed that a heavy tank needed both high-velocity guns for antitank combat and a low-velocity gun for use against infantry, as well as machine guns to cover every potential arc of fire. Hence, multiple turrets were regarded as essential for a breakthrough tank.
As it turned out, the Soviets had not checked Grotte’s qualifications very carefully, for he too had no expertise in tank development. Within just six weeks of arriving in Leningrad, Grotte’s team presented a design to the Military Council and after giving it negligible consideration, Voroshilov approved the design for production. This propensity for making snap decisions on production before prototypes had even been built or properly tested would continue to plague Soviet heavy tank development for the next ten years. Voroshilov also failed to notice that Grotte had ignored the requirements specified by UMM and designed a 20-ton tank mounting a single 76.2mm gun and a 37mm gun, with 30mm of armor protection. Since the Soviets had no tank engines or transmissions in production, Grotte’s team was also tasked with developing a completely new engine and transmission for their tank, which further indicates the lack of serious consideration given by the Military Council. Not surprisingly, Grotte’s team failed to complete a working transmission or engine, but instead cobbled together an existing aircraft engine with a tractor transmission. Somehow, Grotte managed to complete a soft-metal prototype by July 1931, but early trials indicated that the vehicle could barely move. OKMO’s engineers did learn how to construct welded tank chassis from Grotte’s team, but otherwise there was little technical benefit from the experience. One bad habit OKMO engineers acquired from Grotte was using off-the-shelf components such as transmissions, rather than making an effort to design purpose-built components. Aghast at wasting over 15 million rubles and a year of development on Grotte’s scrap-heap tank, the Military Council canceled his project and handed the reins back to OKMO. Grotte remained at OKMO for another year, cranking out a worthless design for a 100-ton tank and wasting resources until he was shown the door and returned to Germany. In order to satisfy Voroshilov – who was equally eager not to disappoint Stalin – Barykov scrambled to develop a prototype T-30 heavy tank to meet the original UMM requirement, but only succeeded in constructing a wooden mock-up by February 1932. The hastily designed T-30 was expected to weigh about 55 tons, mount one 76.2mm gun and one 37mm gun, and have 40–60mm of armor. However, the UMM stuck to its obsession with multiple turrets and when Barykov could not reconfigure the T-30 to meet this requirement, the project was canceled.
A 1937 propaganda poster depicting Stalin and Voroshilov reviewing the Red Army’s May Day parade in Moscow, with the T-35 prominent in the foreground. Stalin believed that heavy tanks were a visible symbol of the military power of the Soviet Union and useful for deterring a German attack. Thanks to these demonstrations, the Germans were aware of the T-35, but not impressed. (Author)
Even before the demise of the T-30, the OKMO team had begun investigating other alternatives. Semyon A. Ginsburg, an engineer from the UMM, visited the United Kingdom on a purchasing mission and paid Vickers ₤20,000 to review the plans for the 16-ton A-6 medium tank under development. Soviet espionage was also successful in gathering other tank design information in England. After this, Ginsburg went to the Tank School at Kazan, where he reviewed all the technical documentation available on Rheinmetall’s Grosstraktor II tank prototype. Armed with this knowledge, Ginsburg joined Barykov’s SKB-1 design team at the Voroshilov plant and was able to sketch out some new designs, employing everything learned from recent British and German developments. However, the UMM decided to split the development effort into two distinct multi-turreted designs, one as a 45-ton heavy tank (T-35) and the other as a 28-ton medium tank (T-28). Barykov assigned Nikolay V. Tseyts’ SKB-2 to design the T-35, while Ginsburg designed the T-28. Tsyets was a rather uninspired tank designer, but his team succeeded in constructing a prototype of the T-35 heavy tank by September 1932. Again with virtually no thought, Voroshilov pressured the UMM into approving the T-35 heavy tank and ordered production to begin as soon as possible. To Voroshilov’s eye, the T-35 was a “land battleship” that would visibly demonstrate the power of the Red Army. In reality, the 45-ton T-35 was an awkward design with a total of five turrets mounting one 76.2mm gun, two 45mm guns (derived from the 3.7cm Rheinmetall gun) and six machine guns, but no more than 30mm of armor. The UMM recognized that the T-35 was an interim solution and directed that production of the T-35 should be shifted to the Kharkov KhPZ tank plant, thereby freeing up OKMO to prepare for a follow-on heavy tank. KhPZ was fully occupied with producing the BT-series fast tanks and needed nearly two years to begin limited production of the T-35. Early trials with the T-35 revealed that it had extremely poor mobility, being barely able to climb gentle slopes, and one commander remarked that, “It couldn’t even traverse a large puddle.” Internally, the 10-man crew could not even move about within the vehicle; and trials revealed that the tank commander could not effectively control the fire of five turrets. Once the deficiencies of the T-35 became apparent, the UMM directed KhPZ to cap production at 61 tanks, while using the existing tanks for experimentation and propaganda purposes. Although the T-35 design did not result in a useful heavy tank, OKMO had learned something about what did not work in a breakthrough tank.
As OKMO engineers struggled to develop a practical heavy tank design, they were also bedeviled by the difficulties Soviet industry faced in providing suitable engines and armament. Early Soviet tanks had to rely upon German-designed aircraft engines, built under license at Rybinsk. Indigenously built tank engines were not available until early 1939; then suddenly there were two alternatives: the GAM-34BT gasoline engine or the V-2 diesel engine. Similarly, prior to 1939 the only 76.2mm weapons available were left over from the Tsarist era. Vasiliy Grabin’s TsAKB artillery design bureau at Gorky did not begin producing purpose-built tank guns until just prior to the outbreak of World War II, commencing with the L-11 and followed by the F-32 and F-34. Even more problematic, artillery development fell under the control of Marshal Grigori I. Kulik, who was opposed to diverting resources for tank gun development and frequently hindered the Red Army’s creation of a heavy tank force. Thus, OKMO’s ability to deliver a useful heavy tank was constrained by having to wait upon developments in the automotive and armaments industries.
After the T-35 fiasco – which wasted more than two years’ worth of development effort – OKMO settled back into trying to develop an effective heavy tank. While the SKB-2 design team at the Kirov plant continued to refine the T-28, Ginsburg and Barykov led the SKB-1 design team in developing new tanks. In 1934, the talented engineer Mikhail Koshkin joined the design team, although Tseyts was still the principal designer. Instead of the clumsy, heavy tanks produced to date, Koshkin envisioned an entirely new 30-ton tank that was relatively fast and designed to resist penetration from a 3.7cm antitank gun, such as the PaK 36. Barykov approved Koshkin’s design, which was designated as the T-46-5 and later the T-111. The T-111 had 60mm of sloped armor protection and a 45mm gun in a cast turret; overall it was a far more sophisticated design that anything Tsyets had developed and Koshkin was awarded the Order of the Red Star for his design. However, Koshkin had shown up the OKMO team and in December 1936 he was transferred to head the design bureau at KhPZ, where he would soon design the revolutionary T-34 tank. OKMO eventually built a prototype T-111 after Koshkin left, but it never entered production.
In May 1937, Stalin began his purge of the Red Army, beginning with the arrest, trial and execution of Tukhachevsky and other top generals. The head designer for SKB-2 was also executed, leaving the effort of designing a new heavy tank leaderless. Into this void, Zhosef Kotin arrived from the UMM not only to head the SKB-2 design team, but to coordinate the development efforts of all three tank factories in Leningrad. Kotin was a trained engineer, but he was also very political and willing to use party connections. Yet contrary to oft-repeated accounts, he was not married to Voroshilov’s daughter.4 Six months later, the new director of the Directorate of Armored Forces (GABTU), Dmitry Pavlov, finally updated the original 1929 requirement for a heavy tank with a new emphasis upon armored protection and the use of a diesel engine. Based upon his experience in Spain commanding Soviet tanks, Pavlov wanted a “shell-proof” tank that was invulnerable to 3.7cm antitank fire and able to resist 7.5cm weapons at ranges of 1,200m. Pavlov was smart enough to see the need not only to counter the current German 3.7cm PaK, but to anticipate Rheinmetall developing a 7.5cm weapon. Kotin was eager to prove his ability to manage an important project, so he gave SKB-1 and SKB-2 just six months to develop designs to meet Pavlov’s requirement. Apparently Kotin thought that competitive rivalry between the two teams would improve the final product but in fact, his decision wasted much of the available engineering talent on redundant designs. In a flurry of activity, both teams tried to pull together lessons learned from the T-35 and the T-111 in order to produce a new design, with the emphasis upon haste, not innovation. Since the GABTU requirement emphasized protection, both teams focused on designing a tank with at least 60mm of frontal armor; but neither was aware that KhPZ had nearly perfected a diesel tank engine, so they continued to rely upon a gasoline engine. Since there was no time to develop a new transmission, Kotin’s engineers took a page from Eduard Grotte’s crash course on designing tanks and simply substituted the transmission from an American Holt 10-ton tractor. Since Kotin was aware that his predecessor had been executed, he figured that completing projects on schedule was more important than the fine details, such as using transmissions designed to move 10-ton tractors to move a 55-ton tank.
Nikolay L. Dukhov (1904–64) was the primary designer of the KV tank. He was a talented engineer in the SKB-2 design bureau and later played a major role in establishing KV production at Chelyabinsk. After the war, Dukhov was recruited into the Soviet nuclear weapons program and helped direct construction of their first atomic bomb in 1949. Although Dukhov played an important role in designing both the KV-1 and the first generation of Soviet nuclear weapons, he is virtually unknown in the West. (Author)
In May 1938, both teams presented their designs to Stalin and Voroshilov, who approved them for further development. Over the next six months, the Barykov/Ginsburg SKB-1 team developed their design as the T-100 tank, while Tseyts’ SKB-2 team worked on their design. Kotin was aware that Koshkin was designing a new medium tank at KhPZ that could compete with his heavy tank designs, so in a blatantly political move, Kotin decided to designate Tseyts’ design as the “SMK” after Sergei Kirov. Both the T-100 and SMK would use the newly developed 76.2mm L-10 gun and the GAM-34BT gasoline engine, as well as torsion-bar suspension.
On December 9, 1938, Kotin went to Moscow to present wooden models of the two heavy tank designs to the State Defense Committee, with Stalin, Voroshilov and Pavlov present. When asked if these 55–58-ton tanks would have better mobility than the 45-ton T-35, Kotin demurred. In response, Stalin broke off one of the 37mm gun turrets from the SMK model and asked how much weight that would save, which brought Kotin’s response of 2.5 tons. Stalin then told Kotin to use the weight saved on armor instead and to consider reducing the design to just one turret, if a single gun could fulfill the antitank and anti-infantry roles. He then approved further development for both designs but specified that a working prototype for each had to be ready by August 1939. Clearly, Stalin suspected that war was coming in Europe and wanted the design bureaus to stop fumbling with interim designs and settle on a practical heavy tank with decent protection and mobility.
Kotin returned to Leningrad and ordered the SKB-1 and SKB-2 design teams to go flat out to produce prototypes by the following summer. However, to hedge his bets, he had SKB-2 assign Nikolay L. Dukhov and some graduate students from the UMM to develop a single-turret version of the SMK as well. It was not until mid-1939 that Kotin became aware that the V-2 diesel engine was ready for production and he quickly sent Dukhov to Kharkov to assess it. Dukhov reported that the V-2 was a major breakthrough in tank motive power, but it was too late to integrate it into the T-100 or SMK prototypes if they were to meet Stalin’s deadline. Instead, Kotin ordered both prototypes completed with the GAM-34BT gasoline engine, but told Dukhov to fit the V-2 into his single-turret variant, which he had decided to name the KV in honor of Voroshilov. Both the SMK and T-100 prototypes were ready ahead of schedule, but the KV was not ready until September 1939. All three prototypes were sent to Kubinka in late September for trials, where they were viewed by Voroshilov and Pavlov. Koshkin was there as well, with his new medium tank, the T-32. Kotin was surprised by the sophistication of the T-32, which demonstrated far superior engineering quality than any of his tanks. Voroshilov regarded all three heavy tank designs favorably, but decided to defer an immediate decision on production.
The SMK tank was the immediate predecessor of the KV-1. OKMO’s conception of the breakthrough tank required a high-velocity 45mm gun in the forward turret, plus a low-velocity 76.2mm gun in the main turret, enabling the SMK to deal with multiple threats. (Author)
Meanwhile, on November 30, 1939, Stalin decided to invade Finland, which Kotin saw as an opportunity to combat-test the three prototypes. OKMO’s entire stable of heavy tank prototypes, consisting of one SMK, two T-100s and two KVs, were sent to the front in Karelia. The five heavy tank prototypes were assigned to the 20th Heavy Tank Brigade, whose deputy commander was Marshal Kulik’s son. On December 19, the tank brigade supported a deliberate attack upon one of the strongest parts of the Mannerheim Line near Summa. Finnish Bofors 37mm antitank guns proved utterly unable to stop the Soviet heavy tanks. Although the heavy tanks succeeded in their breakthrough role by penetrating the Finnish obstacle belt, the SMK was immobilized by a mine and one of the T-100s had an engine failure. Due to poor inter-arms coordination, the Soviet attack was repulsed and the SMK prototype was abandoned. Yet the T-100 demonstrated the value of its armor, which was hit by 14 37mm antitank rounds without a single penetration. The KV prototypes also proved invulnerable to Finnish antitank guns, but the 76.2mm L-11 gun on all three prototypes proved ineffective against enemy bunkers.
After the action at Summa, the SMK was regarded as a failure and the project abandoned, but the two T-100s were repaired and saw further combat in February– March 1940, as did three other KV prototypes. After the first reports from Summa, the State Defense Committee decided to approve the KV for production immediately without further testing, even though it had been driven less than 500km (312mi). However, the inadequacy of a 76.2mm gun against bunkers was apparent and General Kirill Meretskov, commander of the 7th Army in Karelia, requested that a larger-caliber weapon was needed to deal with fortified zones such as the Mannerheim Line. Consequently, GABTU recommended production of the 76.2mm armed model as the KV-1, and a KV-2 assault tank armed with a 152mm howitzer to be developed from the T-100. Working day and night, engineers from the Kirov plant designed the KV-2 in just two weeks and then installed an ML-10 howitzer on a KV hull, creating the first KV-2. Once again, Voroshilov and the State Defense Committee approved another heavy tank for production without adequate testing. Criticism from Soviet tankers in Finland about the KV’s mobility problems was ignored, even though the commander of the 20th Heavy Tank Brigade reported that in one action, “the KV lay in the snow and almost could not move.”
The first KV heavy tank prototype was completed in September 1939 and attempted to squeeze the 45mm and 76.2mm guns from the SMK into a single turret. Production models dispensed with the 45mm gun. (Author)
Combat weight: 47.5 tons
Crew: five (commander, gunner, driver–mechanic, auxiliary driver, radio-operator)
Dimensions
Length with gun: 6.9m
Width: 3.32m
Height: 2.7m
Armor
Hull front: 75+35mm at 60 degrees
Hull sides: 75+35mm at 90 degrees
Hull rear: 60–75mm at 40 degrees
Hull roof: 35mm at 0 degrees
Turret front/mantlet: 75/90mm at 70 degrees/round
Turret sides: 75+35mm at 75 degrees
Turret rear: 75mm at 75 degrees
Turret roof: 35mm at 0 degrees
Armament
Main gun: 1 x 76.2mm F-33 L/42
Secondary: 3 x 7.62mm DT (coaxial, rear, hull)
Main gun rate of fire: 4–8 rds/min
Gunsight: PT4-13 with 26-degree field of view
Ammunition stowage
Main gun: 114 rounds (28 rounds BR-350A APHE, 86 rounds OF-350 HE-FRAG)
Secondary: 2,150 rounds
Communications
71-TK-3 radio; TPU-4-bis intercom
Motive power
Engine: V-2 12-cylinder diesel
Power: 600hp
Transmission: 5 gears forward, 1 reverse
Fuel capacity: 600l diesel
Power-to-weight ratio: 12.63hp/ton
Performance
Ground pressure: 0.84kg/cm2
Maximum road speed: 28km/h (17mph)
Maximum cross-country speed: 16km/h (10mph)
Operational range: 250km (156mi) (road), 180km (112mi) (cross-country)
Fuel consumption: 2.4l/km (road)
Cost: 635,000 Rubles ($120,000 or 300,000 RM)
Regular production of the KV-1 and KV-2 began at the Kirov plant in June 1940, although the State Defense Committee instructed the Chelyabinsk Tractor Plant (CTZ) also to begin tooling up for production of the KV. Between June 1940 and June 1941, monthly production rose to 50–60 KVs, split roughly between KV-1 and KV-2. The very first KVs built were assigned to the 20th Heavy Tank Brigade in Leningrad, which made sense since the tanks were thus close enough to the Kirov plant to remedy any defects quickly. Pavlov recommended that all new KV battalions should be formed in Leningrad for ease of training and repair, before dispatching them to join the mechanized corps in the various military districts. However, Stalin was personally interested in the KV and only two months after production began in Leningrad, he ordered all available KVs sent to the 4th Mechanized Corps in the Kiev Military District. Stalin’s desire to get KVs to frontline units as fast as possible undermined both the refinement of the KV design at the Kirov plant and the amount of training Soviet tankers received on the new weapon.
The KV-1 was intended to fulfill the role of a breakthrough tank, with an ability to punch through an enemy fortified area defended by antitank guns and then advance at least 10–15km into the enemy depth to overrun their artillery. The GABTU believed in specialization, with the KV-1 creating the breakthroughs that the more mobile T-34 and light tanks would exploit. Kotin’s KV-1 appeared to be the breakthrough tank envisioned by Tukhachevsky, and Stalin expected it to provide the Red Army with a decisive advantage.
In February 1925, the Reichswehr quietly began to issue requirements for new weapons, beginning with the need for a new antitank weapon and a light infantry gun. However, the two primary German artillery manufacturers – Rheinmetall in Düsseldorf and Krupp in Essen – were at that time under virtual lockdown due to the French occupation of the Ruhr. The Inter-Allied Control Commission had forced Rheinmetall to lay off 9,000 workers and sell most of its machine tools, leaving it with little remaining capacity for weapons production. It was not until August 1925 that French troops evacuated the Ruhr and both companies could resume their traditional roles as suppliers of German armaments. Rheinmetall was given the nod by the Heereswaffenamt for both new weapons, although an actual contract was not forthcoming until June 1927.
Based upon their experience from World War I and the limited financial resources of the Reichswehr, the German preference was for inexpensive, light, mobile antitank guns that could be mass-produced and distributed in depth. Rheinmetall was selected because its engineers had built the successful 3.7cm TaK 36 and because Krupp was more interested in developing heavy artillery. Dr Carl Waninger was put in charge of a team of 25 engineers who worked in secret at an abandoned firing range on Lüneberg Heath. In just over six months, Waninger’s team built the first 3.7cm TankAbwehrkanone (standardized as the 3.7cm PaK L/45) prototype. In ballistic terms, this 3.7cm gun was a very advanced design for 1928 and no other country had a similar antitank gun at this point. The Heereswaffenamt decided not to risk test firing the prototype in Germany due to the vigilance of Allied inspectors and instead covertly shipped a few 3.7cm guns to the school at Kazan, where they demonstrated the gun’s ability to penetrate 29mm of armor plate at a distance of 500m. Satisfied with Rheinmetall’s prototype, the Heereswaffenamt approved low-rate production of 14 weapons per year in May 1929. The modest objective was to eventually equip each Reichswehr division with 36 PaK guns. Yet the Reichswehr did not want openly to violate the Treaty of Versailles, so the PaK guns were put in storage and troops continued to train with wooden antitank guns.
The first 3.7cm PaK L/45 was covertly designed by Dr Carl Waninger’s small Rheinmetall design team in the late 1920s. With its wooden-spoked wheels, this weapon was not designed to be towed at high speed by a vehicle. Despite the restrictions of the Treaty of Versailles, Germany succeeded in deploying the first high-velocity antitank gun in the world. (Author)
However, this low-rate production contract was not profitable for Rheinmetall, and the constraints imposed upon German arms firms made it unlikely that this would change as long as the treaty was enforced. Eager to develop profitable arms sales, particularly in Depression-era Germany, Rheinmetall turned to the Soviets. Rheinmetall’s agents contacted the Soviet front company BYUTAST, which had been established to procure arms technology from the West. On August 28, 1930, Rheinmetall signed a secret contract worth $1.125 million to provide antitank technology to the Soviet Union, including a dozen 3.7cm PaK L/45 guns and designs for five other artillery weapons. Using their PaK L/45 as a starting point, Rheinmetall’s engineers designed the 37mm M1930 (1-K), which was built at Plant No 8 in Kalinin for the Red Army. As it turned out, Soviet factories had difficulty producing a weapon like the 1-K and barely 400 were built in 1931–33 before the Soviets decided to design their own weapon and increase the size to 45mm. In the process, Soviet engineers learned a good deal about German antitank developments.
Thanks to the capital infusion from the Soviets, Rheinmetall was able to continue development of the 3.7cm PaK gun, as well as beginning work on a number of new weapons, including 2cm Flak guns and 10.5cm and 15cm medium howitzers. Between 1928 and 1933, Rheinmetall made little effort to improve the 3.7cm PaK L/45, but once Hitler became chancellor in 1933, it was clear that the restrictions of the Treaty of Versailles would soon be renounced. Hitler favored the development of motorization in the German Army and the Truppenamt (Troop Office) led by Generalleutnant Ludwig Beck, moved to align new weapons development with this objective. Since the 3.7cm PaK L/45, with its wooden spoked wheels, was designed to be pulled by horses as German artillery traditionally had been, it was clear that the PaK was inconsistent with the push toward motorization. In September 1934, Beck directed Rheinmetall to modify the 3.7cm PaK to be towed by motor vehicles and subsequently, pneumatic tires, which replaced the wooden wheels and springs, were added on the carriage. The modified PaK was available early in 1935 and standardized as the 3.7cm PaK, with the Krupp Protze (Kfz 69, limber 69) designated as its preferred towing vehicle. When Hitler renounced the military restrictions of the Treaty of Versailles in March 1935, Rheinmetall was directed to begin mass production of the 3.7cm PaK and Wehrmacht troops began to train on it. Work was also begun on improved antitank rounds for the 3.7cm PaK, including the use of tungsten-carbide penetrators.
Three other important antitank developments occurred within Germany in the 1930s. First, an engineer in Hamburg, Hermann Gerlich, experimented with tapered-bore barrels to increase muzzle velocities on rifles. Although Gerlich died in 1935, his concepts created interest in applying this type of technology to antitank weapons and the Mauser company began development of a tapered-bore antitank weapon. Since the Wehrmacht had no official requirement for this type of weapon, Mauser conducted the development on its own initiative. It took nearly five years to create a working prototype. The first prototype, designated the 2.8cm sPzB 41, was not ready until early 1940 but tests indicated that it had better penetration than the 3.7cm PaK and weighed significantly less, which validated the tapered-bore concept. The Heereswaffenamt now took an interest in tapered-bore weapons and directed both Krupp and Rheinmetall to investigate larger weapons using this principle. However, a number of problems with the tapered-bore concept were evident from the beginning, including greatly reduced barrel life, a rapid drop-off in performance after 500m, and reliance on scarce tungsten penetrators.
The 3.7cm PaK was not openly used in German Army training until after Hitler came to power in 1933. In order to keep up with the Wehrmacht’s new doctrines on mobile warfare, in 1935 the 3.7cm PaK was upgraded with pneumatic tires and better suspension. (Ian Barter)
Manufacturer: Rheinmetall-Borsig
Crew: 6
Prime mover: Kfz 69 Krupp-Protze
Length: 3.4m
Width: 1.65m
Height: 1.17m
Weight: 440kg
Elevation: +25 degrees/–8 degrees
Traverse: 59 degrees
Rate of fire: 15–18 rds/min
Barrel life: 4,000–5,000 rounds
Gunsight: ZF 1 x 11 (3 x magnification, 11-degree field of view)
Maximum engagement range: 600m
Ammunition: PzGr 39 AP, PzGr 40 APCR, Stielgranate 41
Cost: 5,730 RM ($2,292 or 12,147 Rubles)
Manufacturer: Rheinmetall-Borsig
Crew: 5
Prime mover: SdKfz 7, 8 or 11
Length: 4.75m
Width: 1.83m
Height: 1.1m
Weight: 986kg
Elevation: +27 degrees/–5 degrees
Traverse: 65 degrees
Rate of fire: 12–14 rds/min
Barrel life: 4,000–5,000 rounds
Gunsight: ZF 3 x 8 (3 x magnification, 8-degree field of view)
Maximum engagement range: 1,500m
Ammunition:PzGr 38 AP, PzGr 40 APCR
Cost: 8,000 RM ($3,200 or 16,690 Rubles)
A German 3.7mm PaK crew in action in Russia, June 1941. This photo from SIGNAL magazine depicts the Panzerjäger without camouflage and in the middle of the road, which would lead to their quick annihilation if up against KV heavy tanks. (Author)
The Heereswaffenamt had also been interested in the efficacy of Hohlraumgranaten (hollow-charge or HEAT shells), but no practical design emerged prior to 1935. Hollow-charge ammunition had the potential to penetrate thick armor plate with a jet of gas but without the requirement for high muzzle velocities or scarce metals. Furthermore, hollow-charge shells could be fired from almost any artillery piece, not just dedicated PaK guns. A Swiss inventor in Zurich, Henry Mohaupt, was the first to perfect a hollow-charge antitank warhead in 1935 and was able to sell it to the French Army. Around the same time, an Austrian chemical engineer, Franz R. Thomanek, made similar progress in hollow-charge design, possibly with information gleaned from Mohaupt’s research. After the Austrian Anschluss, Thomanek was hired by the Luftwaffe and worked at a research institute in Braunschweig where he perfected his own hollow-charge warhead. Early tests were promising, indicating that the warheads could penetrate 70–80mm of armor plate, so in late 1939 the Heereswaffenamt authorized Thomanek to create a company for the manufacture of hollow-charge warheads. However, fusing was a problem with early hollow-charge ammunition and the shells worked best in low-velocity howitzers, not high-velocity PaK guns. Consequently, the first hollow-charge antitank ammunition issued in late 1941 was 7.5cm rounds for the PzKpfw IV tank and StuG III assault gun; the Panzerjäger would not receive hollow-charge rounds until early 1942.
Manufacturer:Rheinmetall-Borsig
Crew: 8
Prime mover: SdKfz 7, 8 or 11
Length: 3.45m
Width: 2m
Height: 1.25m
Weight: 1,500kg (1,425kg deployed)
Elevation: +22 degrees/–5 degrees
Traverse: 65 degrees
Rate of fire: 11–14 rds/min
Barrel life: 6,000 rounds
Gunsight: ZF 3 x 8 (3 x magnification, 8-degree field of view)
Maximum engagement range: 1,800m
Ammunition: PzGr 39 AP, PzGr 40 APCR, Gr 38 Hl/B HEAT
Cost: 12,000 RM ($4,800 or 25,440 Rubles)
The third major antitank development in Germany was the growing interest in mounting PaK guns on vehicles. In 1930, Rheinmetall mounted a 3.7cm PaK L/45 on an experimental tracked chassis at Kazan, but no orders were placed. Once the first Panzer divisions were formed in 1935, there was a realization that the lightly armed early tanks were not suited for fighting other tanks, and that putting high-velocity guns on even the PzKpfw III and PzKpfw IV would require major turret modifications. However, a large high-velocity antitank gun could easily be mounted on a turretless tank chassis or large half-track vehicle, thereby creating an open-ended architecture for future weapons growth. In 1935, Oberstleutnant Walter Nehring, the operations officer for Generalmajor Oswald Lutz’s Inspectorate for Motor Transport Troops, developed an official requirement for self-propelled tank destroyers, although the ad hoc experimentation was confined to existing vehicles and weapons. It was not until war began in 1939 that the Heereswaffenamt put serious resources into this effort, by deciding to mount the Czech 4.7cm PaK 36(t) on the hulls of surplus PzKpfw I light tanks. The conversion effort began in the winter of 1939/40 at the Alkett facility in Berlin, which was a subsidiary of Rheinmetall. The resulting conversion was designated as the Panzerjäger I, and it was assigned to four army-level Panzerjäger battalions just in time for the French campaign in 1940. Although the vehicle was more than double the height of either the 3.7cm or 5cm PaK – and thus easier to spot – it could keep up with the Panzers and its 4.7cm gun could penetrate up to 47mm of armor at 500m. After the fall of France, the Heereswaffenamt ordered further development of self-propelled antitank guns, with an eye toward mounting 5cm and eventually 7.5cm antitank guns on surplus tank hulls, although no urgency was applied to this effort.
When the Wehrmacht began its modernization program in 1935, the 3.7cm PaK seemed adequate for the foreseeable future. There were still virtually no foreign heavy tanks in service and tanks heavier than 20 tons were still rare. When Hitler decided to send the Condor Legion to intervene in the Spanish Civil War, the 3.7cm PaK performed well against Soviet-built T-26 and BT-5 tanks. These 10–11-ton tanks, with no more than 15mm armor plate, proved vulnerable to standard Panzergranate shells from the 3.7cm PaK at ranges well beyond 500m. The Heereswaffenamt was aware of the Soviet T-35 heavy tank, but it was the introduction of the French H-35, R-35 and SOMUA 35 tanks in 1935–36, followed by the 31-ton Char B1 bis in 1937, that caused the Germans to reconsider reliance on just the 3.7cm PaK. The new French infantry tanks had armor protection ranging from 30mm to 60mm, which reduced the effective range of the 3.7cm PaK to less than 500m. Consequently, the Heereswaffenamt issued a requirement for a 5cm antitank gun, with a contract awarded to Rheinmetall in May 1938. Rheinmetall’s engineers decided to increase the length of the barrel as well as the diameter of the bore, but the basic configuration of the towed antitank gun remained the same. Although the Heereswaffenamt provided Rheinmetall with data on current French tanks, there was no information on current Soviet tanks. A prototype of the 5cm gun was available by August 1939 and firing tests indicated that the weapon could penetrate 57mm of armor at 500m, nearly doubling the penetration power of the 3.7cm PaK. The new weapon was standardized as the 5cm PaK 38, but limited production did not begin for another year. Soon after the war began, the Heereswaffenamt began discussions with both Rheinmetall and Krupp about developing a follow-on 7.5cm PaK gun to counter enemy heavy tanks, but no contracts were awarded.
The Germans began experimenting with antitank guns mounted on trucks in World War I and they expanded upon this tradition in World War II. The Panzerjäger I was created in early 1940 by mounting the Czech-built 4.7cm antitank gun on the hull of a PzKpfw I tank and these vehicles first saw combat in France. The Panzerjäger I was the primary German self-propelled antitank gun at the start of Barbarossa. (Nik Cornish at Stavka, WH 1088)
The German engineer Hermann Gerlich perfected a tapered-bore design in the 1930s, which – when combined with tungsten-core ammunition – enabled lightweight antitank guns to achieve extraordinary muzzle velocity and penetration. The 2.8cm sPzB 41 was the first such weapon to enter service and limited numbers were available for Operation Barbarossa. Two larger tapered-bore weapons were in development that could enable the Wehrmacht to gain a decisive advantage in the contest between penetration and armor plate. (Ian Barter)
The 5cm PaK 38 was regarded as the logical successor to the 3.7cm PaK after the French campaign, but Rheinmetall was unable to produce the weapon in quantity prior to Operation Barbarossa. When equipped with PzGr 40 tungsten-core ammunition, the PaK 38 had a limited ability to defeat KV heavy tanks. (Ian Barter)
Prior to Operation Barbarossa, Germany had perfected both tungsten penetrators and hollow-charge shells that could defeat heavy tanks, but neither was in widespread use since the threat of heavy tanks appeared negligible. However, once German troops encountered the KV-1 and T-34 tanks on the battlefield in June 1941 and discovered the ineffectiveness of their current PaK guns, the Heereswaffenamt initiated a frantic effort to develop new weapons or adapt existing ones to counter the threat. The resulting effort to upgrade the capabilities of German Panzerjäger units quickly was marked by garbled requirements and uncoordinated improvisation, which pushed for greater firepower but at the expense of protection and mobility.
Rheinmetall’s 75mm PaK 40 would eventually become the primary defense against the KV heavy tank in 1942–43, although this was not immediately obvious in June 1941. Development of the PaK 40 was a low priority before Barbarossa and Rheinmetall could not design, test and build the new gun in much less than a year. (Ian Barter)
2 All tonnages given in the book are metric tons (please see the conversion chart on page 2).
3 The UMM was renamed the Automotive and Armored Vehicle Directorate (ABTU) in 1934, then GABTU in 1940.
4 He was married to an engineer from the UMM named Nataliya Poklonova.