A pillbox can cover a certain sector of terrain with its fire. If the enemy attacks in a different place, there is no way to move it over. Or is there? The issue of moving pillboxes around has been tackled by many inventors. The simplest solution was to put them on wheels. German inventor Maximilian Schumann was the first to propose this solution towards the end of the 19th century. His armoured pillboxes were widely used by the Germans in early WWI. A drawback of his design was that they were impossible to move in combat and that an external power sources was needed.
The optimal solution would be a self-propelled pillbox. During the Great Patriotic War, many inventions of this type were designed. Many of them look exotic and strange, but they were very seriously reviewed at the highest levels.
Alekseenko's Walking Pillbox
In late June of 1942, one such invention came from the city of Magnitogorsk. The people who were involved in the discussion signify how seriously this invention was considered. The first person to familiarize himself with the project was the chief of the Leningrad armour commanders' continuing education academy, Major-General A.V. Borzikov. He passed this project on to the chief of GABTU, Lieutenant-General Ya.N. Fedorenko. In the accompanying letter, he wrote that he spoke with the People's Commissar of Black Metallurgy I.F. Tevosyan and that the production of a prototype was approved if Fedorenko agreed. What was this wonder-weapon that was noticed by such senior commanders?
The author of the walking pillbox was engineer Alekseenko, who worked at the Magnitogorsk metallurgy plant. The vehicle, designed in part by members of the armament section of the plant, was an aerodynamic design, a little less than 5 meters long, 3.8 meters wide, and 1.7 meters tall. Its mass was 45 tons. This mass can be explained by the fact that the pillbox's armour reached 200 mm, impenetrable to any existing field artillery. The vehicle was armed with a 76 mm gun with 100 shells, as well as three DT machineguns.
The vehicle was powered by a GAZ M-11 76 hp engine. It might seem that the authors made a mistake in proposing such a humble power plant, but remember that this is a pillbox and not a tank, and it wasn't in any hurry. Its maximum speed was 2 kph. As the title of the project suggests, the pillbox would walk on two "legs", similar to a walking excavator.
One step would move the vehicle 1.3 meters. In combat, the "legs" would be raised and the bottom of the hull would be placed on a flat surface. The top of the pillbox could spin, giving it 360 degrees of range.
The "walking pillbox" project was done at a very high technical level and used components from existing vehicles, which simplified production. This is why such senior staff took an interest.
However, Fedorenko rejected the design, and it remained in archives.
Viert's Crawling Vibrating Monster
An even more original proposition was sent personally to Stalin in August of 1943. The author, engineer-designer from aircraft factory #89 V.I. Viert, proposed a vehicle that he called "crawling vibrating pillbox". The name is strange and intriguing, but the concept is far from insanity. Like Alekseenko's walking pillbox, Viert's design was based on existing solutions. However, unlike walking excavators, vibration drives did not ever progress past functional models.
Viert's invention resembled a puck with a curved top. The design was relatively simple. Special flywheels were placed inside the hull, the rotation of which would cause vibrations in one direction or other. In other words, the vehicle would start hopping. To compensate for the impacts, the author added a sprung suspension to the foundation of the pillbox. According to Viert, his vehicle would be able to entrench itself, all it would have to do is jump in place.
As this was only a conceptual design, the author did not pay much attention to armour or armament. However, it is known that the author expected his creations to fight the heaviest of enemy tanks.
Unlike the walking pillbox, which was declined and forgotten, Viert's story is more dramatic. The first draft of the design was proposed back in September of 1941. The design was declined several times, but Viert's persistence persevered. Aside from diagrams, the inventor also built working models of his vehicle that proved it could be possible to built such a device.
Viert showed his invention to professors Christie and Gruzdev at the Military Academy of Mechanization and Motorization. Viert's last attempt was a letter directly to Stalin, which brought no results, as it was forwarded to the same people who already rejected the inventor's proposal. The project was left in the archives.
Original article available here.
This blog is dedicated to bringing World War II era documents to the general public, with an overall focus on armoured warfare. Questions? Requests? Comments? Email me at tankarchives@gmail.com or find me on Twitter @Tank_Archives.
Sunday, 10 January 2016
Saturday, 9 January 2016
T-220: Prototype in Combat
There is an opinion that the Red Army dropped other tank projects for some time after the appearance of the KV tank. Indeed the SMK and T-100 heavy tanks were cancelled in the summer of 1940. However, it became necessary to improve the armour and armament of the tank immediately afterwards, resulting in even heavier tanks like the KV-4 and KV-5. The first step in this journey of increasing firepower, armour, and eventually size and mass was the KV-220 tank, later renamed T-220. Even though only two were made, both participated in battle during the Great Patriotic War.
Big Gun
The first signs that neither the "small turret" KV nor the "large turret" variant were satisfactory for the army were seen in June of 1940. According to a proposal for improvement of tank guns, the KV-1 should be armed with a 76 mm gun with the ballistics of the model 1931 AA gun (3-K). It was also proposed that the front armour be increased to 90-100 mm.
Some doubts arose regarding the 3-K. According to calculations, the 76 mm AA gun could penetrate 70 mm of armour at 1000 meters at an angle of 30 degrees. This is a good amount, but it turned out that the thickness of the KV-1's armour would be greater than this value. In addition, the 3-K was already removed from production, replaced with a new more powerful 85 mm AA gun that could penetrate 88 mm of armour under the same conditions.
It is not surprising that two new guns appeared of tank, SPG, and anti-tank guns: a 76 mm gun with AA ballistics and an 85 mm gun with AA ballistics. The due date for arming a KV with a small turret with both of the guns was set as September 1st, 1940. Factory #92 was chosen to develop both systems.
The gun with 3-K ballistics was indexed F-27, and the gun with 52-K ballistics was indexed F-30. The factory's chief designer, V.G. Grabin, was in charge of both projects. Much hope rested on the F-30: according to defense plans for 1940, 50% of KV tanks would be armed with this gun.
Both guns were ready by the due date and already began trials. Factory #92 didn't reinvent the wheel and followed the development path of the F-34. Using that gun as the basis, the design bureau installed new barrels and strengthened the recoil mechanisms. Thanks to this approach, the design of the guns took a short time. By September 2nd, 1940, the F-27 performed 5 trials of 122 shots in total, with satisfactory results.
By that time, the F-30 performed 2 trials of 68 shots in total. Some design flaws were discovered in the process, and the factory began working on improvements. By September 24th, the gun made 90 shots, after which a crack in the breech was discovered. Trials of the F-30 continued until October 29th, after which the gun was removed from the T-28 and sent to the Kirov factory. At the same time, factory #92 began building another F-30 prototype, which they finished in late October, but further trials stalled.
Growing Appetites
On July 17th, 1940, SNK and VKP(b) decree #1288-495ss was issued, according to which Kirov factory was tasked with producing two prototypes of improved KV tanks by December 1st, 1940. Both prototypes were to have 100 mm of front armour, but differed in armament; the first prototype got the 76 mm F-27 gun, and the second the 85 mm F-30. However, changes were soon made. Instead of the F-27, the 76 mm F-32 gun was used, and the front armour was decreased to 90 mm. In addition, it turned out that the F-30 did not fit into the existing KV-1 turret, and a new turret was necessary.
It was not possible to just change the turret, as the required changes snowballed. In the end, the tank that was referred to as KV-220, Object 220, and T-220 significantly differed from the initial KV-1, having almost caught up to the SMK in size and surpassed it in mass. The T-220 was also called KV-4 in writing at least once.
The design of this tank is connected with the 212A SPG, whose design was ordered by the same decree #1288-495ss. As the mass of the "bunker buster" crawled over 60 tons, it needed a new engine. This engine, indexed V-2SN, was developed at factory #75 in Kharkov. It differed from the stock V-2 by the addition of the mechanical supercharger from the AM-38 aircraft engine. The supercharger increased the power output of the engine to 850 hp. This engine was also installed in the T-220, along with a new gearbox, main clutch, and final drives.
All these changes lengthened the hull to 7820 mm, one meter longer than the KV-1. This increase resulted in a change to the running gear: there were now 7 road wheels and 4 return rollers. The front of the hull was 100 mm thick, same as the sides. Initially, the mass of the T-220 was estimated at 56 tons, but the tank grew to 62.7 tons.
The turret that led to this growth of mass and size was a further development of a lowered KV-2 turret. The front was taken up by the massive F-30 gun mount and a coaxial machinegun. A hatch in the rear of the turret, much like the one on the KV-2, was added for removal of the gun. Another machinegun was installed in a rotating commander's cupola. A second loader increased the number of turret crewmen to 4. The ammunition, 91 rounds in total, was also partially stored in the turret.
The development of the T-220 was not cheap. According to calculations made by the Kirov factory, the total budget of this project reached 4 million roubles. 100,000 of them were spent on the technical project, 25,000 on the model, 250,000 on design documentation, and 75,000 on corrections made after trials. Two experimental prototypes would cost 1.2 million apiece. Trials would cost half a million, and another 900,000 would be used to improve the prototypes after trials, and all this doesn't include the cost of the armament.
Unlucky Sign
Due to a large amount of assignments for the Kirov factory and a general overload of work, the tanks were not finished on time. The hull only arrived at the factory on December 7th, 1940, and assembly was complete by early January 1940. A mix-up occurred during assembly: the F-30 gun was not properly balanced. Gunnery trials were moved to a later date that never came.
On January 14th, 1941, the trials plan was approved. Factory trials were skipped in a hurry. This fact contributed to the subsequent events. Trials showed a large amount of problems with the V-2SN engine. The piston rings wore out quickly, and the engine spat out oil. Oil consumption nearly reached one liter per kilometer.
The maximum speed on a highway was 33 kph, and average speed was 21.2 kph. However, the T-220 did not drive around for long. On January 25th, after 106 kilometers driven on a highway, the engine broke. As there were no spares, trials were halted. It's worth mentioning that this was not a surprise for factory #75 representatives. Chief designer of factory #75 T.P. Chupakhin said that the engine was experimental and that he gave no guarantees regarding its reliability.
Trials continued in late January after another engine was shipped from factory #75, if only briefly. According to a report by military engineer 1st class Glukhov, the second engine broke down completely on February 3rd, 1941. The next engine was expected to arrive on February 15th, and trials were falling behind schedule. Assembly of the second T-220 lagged behind due to missing parts. In early February 1941, the turret was still at factory #92 where the F-30 gun and its equipment were being installed.
Finally, instead of a V-2SN engine, a 700 hp V-5 arrived from factory #75. By the time it arrived, several important events happened that would change the fate of the T-220.
Grabin did not forget the idea to install a 107 mm gun with ballistics of the divisional M-60 gun in the KV-2 turret. In December of 1940, it became known that the design bureau of factory #92 developed such a gun on their own initiative and is already starting to build it. This gun, indexed F-42, was proposed for installation into the T-220 turret, but was rejected. It was decided that the lighter T-150 would be put into production under the index KV-3. The T-220 prototype would serve as a testbed for the V-5 engine, which would be used on the KV-3. The same thing happened to the V-5 as to the V-2SN: it didn't last long in the T-220.
The fate of the T-220 was sealed in March of 1941. Information on heavy tanks in the German army began to arrive. Information received by Soviet intelligence led to significant increase in activity regarding tanks and tank armament. This activity also touched domestic heavy designs. The T-220 with an 85 mm gun and 100 mm of armour was deemed insufficient. Instead, a new 72 ton KV-3 started development, with the factory index 223. Overall, this tank would be further development of the T-220, with more powerful armament and 120 mm of armour.
Work on the new KV-3 didn't mean that the existing T-220 was forgotten. On the contrary, the prototype was used as much as possible by the Kirov factory as a testbed for parts and assemblies meant for the new tank. A third V-2SN was installed, this one much more reliable than its predecessors. The tank was used to test new road wheels and Vortex air filters. By June 20th, 1941, it travelled a total of 1979 km. As for the other T-220 prototype, Kirov factory only got to it in early June. Assembly went along lazily, and was planned for no earlier than mid-July. This was how the experimental vehicles met the start of the Great Patriotic War.
Battles for Leningrad
All work on the T-220 stopped after the start of the war. The factory began hurriedly producing KV-1s, focusing their efforts on simplifying the design. When evacuation of the factory began, the KV-3 hull was evacuated. As for the T-220s, nobody had time for them. This changed when the Germans reached the city in the fall of 1941 and any tank at all was worth its weight in gold.
Suddenly, people remembered about the T-220s. Since the tanks never fired a shot and one turret was still in Gorkiy at factory #92, the first T-220 had its turret replaced with a stock KV-1 turret with an F-32 76 mm gun. The same turret was installed on the second tank. On October 5th, 1941, tank T-220 with serial number M-220-1 was sent to the 124th Tank Brigade. On October 16th, the second tank was sent there with the index M-220-2.
In November of 1941, the 124th Tank Brigade and the 43rd Infantry Division fought fierce battles near Ust-Tosno. The second T-220 burned up in these battles along with its crew, commanded by Junior Lieutenant Yakhnin. According to memoirs, the tank carried the slogan "For the Motherland!". As for the first prototype, its fate is unknown.
The story of the T-220 could end here, but it goes on. On February 8th, 1943, order #012 regarding assigning crews to the 12th Independent Training Tank Regiment. The eighth tank in the list is... "For the Motherland", serial number 220-2, whose commander was V.V. Strukov.
How could this be? Usually, burned up vehicles could not be repaired, but there are exceptions. It is known that at least several burned up KV-1s were evacuated and kept on fighting. It is also known that 17 tanks from the 124th Tank Brigade were recovered. One of them must have been M-220-2, repaired in the winter of 1942 at factory #371. During repairs, it was equipped with a V-2K engine, serial number 1193-03. The tank no longer had any worth as a combat vehicle, but it worked as a hands-on training aid for tankers until 1944.
The last episode in the life of the T-220 was the use of its turret. In September of 1941, the turret was replaced with a production KV-1 turret. The tankless turret was found a home. It was installed on a concrete foundation in the 22nd Karelian Fortified Region. The result was called Artillery BOT (KV) with 85 mm gun "Victory". Here, the turret survived the whole war.
Original article by Yuri Pasholok.
Big Gun
The first signs that neither the "small turret" KV nor the "large turret" variant were satisfactory for the army were seen in June of 1940. According to a proposal for improvement of tank guns, the KV-1 should be armed with a 76 mm gun with the ballistics of the model 1931 AA gun (3-K). It was also proposed that the front armour be increased to 90-100 mm.
Some doubts arose regarding the 3-K. According to calculations, the 76 mm AA gun could penetrate 70 mm of armour at 1000 meters at an angle of 30 degrees. This is a good amount, but it turned out that the thickness of the KV-1's armour would be greater than this value. In addition, the 3-K was already removed from production, replaced with a new more powerful 85 mm AA gun that could penetrate 88 mm of armour under the same conditions.
It is not surprising that two new guns appeared of tank, SPG, and anti-tank guns: a 76 mm gun with AA ballistics and an 85 mm gun with AA ballistics. The due date for arming a KV with a small turret with both of the guns was set as September 1st, 1940. Factory #92 was chosen to develop both systems.
The gun with 3-K ballistics was indexed F-27, and the gun with 52-K ballistics was indexed F-30. The factory's chief designer, V.G. Grabin, was in charge of both projects. Much hope rested on the F-30: according to defense plans for 1940, 50% of KV tanks would be armed with this gun.
Both guns were ready by the due date and already began trials. Factory #92 didn't reinvent the wheel and followed the development path of the F-34. Using that gun as the basis, the design bureau installed new barrels and strengthened the recoil mechanisms. Thanks to this approach, the design of the guns took a short time. By September 2nd, 1940, the F-27 performed 5 trials of 122 shots in total, with satisfactory results.
By that time, the F-30 performed 2 trials of 68 shots in total. Some design flaws were discovered in the process, and the factory began working on improvements. By September 24th, the gun made 90 shots, after which a crack in the breech was discovered. Trials of the F-30 continued until October 29th, after which the gun was removed from the T-28 and sent to the Kirov factory. At the same time, factory #92 began building another F-30 prototype, which they finished in late October, but further trials stalled.
Growing Appetites
On July 17th, 1940, SNK and VKP(b) decree #1288-495ss was issued, according to which Kirov factory was tasked with producing two prototypes of improved KV tanks by December 1st, 1940. Both prototypes were to have 100 mm of front armour, but differed in armament; the first prototype got the 76 mm F-27 gun, and the second the 85 mm F-30. However, changes were soon made. Instead of the F-27, the 76 mm F-32 gun was used, and the front armour was decreased to 90 mm. In addition, it turned out that the F-30 did not fit into the existing KV-1 turret, and a new turret was necessary.
It was not possible to just change the turret, as the required changes snowballed. In the end, the tank that was referred to as KV-220, Object 220, and T-220 significantly differed from the initial KV-1, having almost caught up to the SMK in size and surpassed it in mass. The T-220 was also called KV-4 in writing at least once.
The design of this tank is connected with the 212A SPG, whose design was ordered by the same decree #1288-495ss. As the mass of the "bunker buster" crawled over 60 tons, it needed a new engine. This engine, indexed V-2SN, was developed at factory #75 in Kharkov. It differed from the stock V-2 by the addition of the mechanical supercharger from the AM-38 aircraft engine. The supercharger increased the power output of the engine to 850 hp. This engine was also installed in the T-220, along with a new gearbox, main clutch, and final drives.
All these changes lengthened the hull to 7820 mm, one meter longer than the KV-1. This increase resulted in a change to the running gear: there were now 7 road wheels and 4 return rollers. The front of the hull was 100 mm thick, same as the sides. Initially, the mass of the T-220 was estimated at 56 tons, but the tank grew to 62.7 tons.
The turret that led to this growth of mass and size was a further development of a lowered KV-2 turret. The front was taken up by the massive F-30 gun mount and a coaxial machinegun. A hatch in the rear of the turret, much like the one on the KV-2, was added for removal of the gun. Another machinegun was installed in a rotating commander's cupola. A second loader increased the number of turret crewmen to 4. The ammunition, 91 rounds in total, was also partially stored in the turret.
The development of the T-220 was not cheap. According to calculations made by the Kirov factory, the total budget of this project reached 4 million roubles. 100,000 of them were spent on the technical project, 25,000 on the model, 250,000 on design documentation, and 75,000 on corrections made after trials. Two experimental prototypes would cost 1.2 million apiece. Trials would cost half a million, and another 900,000 would be used to improve the prototypes after trials, and all this doesn't include the cost of the armament.
Unlucky Sign
Due to a large amount of assignments for the Kirov factory and a general overload of work, the tanks were not finished on time. The hull only arrived at the factory on December 7th, 1940, and assembly was complete by early January 1940. A mix-up occurred during assembly: the F-30 gun was not properly balanced. Gunnery trials were moved to a later date that never came.
On January 14th, 1941, the trials plan was approved. Factory trials were skipped in a hurry. This fact contributed to the subsequent events. Trials showed a large amount of problems with the V-2SN engine. The piston rings wore out quickly, and the engine spat out oil. Oil consumption nearly reached one liter per kilometer.
The maximum speed on a highway was 33 kph, and average speed was 21.2 kph. However, the T-220 did not drive around for long. On January 25th, after 106 kilometers driven on a highway, the engine broke. As there were no spares, trials were halted. It's worth mentioning that this was not a surprise for factory #75 representatives. Chief designer of factory #75 T.P. Chupakhin said that the engine was experimental and that he gave no guarantees regarding its reliability.
Trials continued in late January after another engine was shipped from factory #75, if only briefly. According to a report by military engineer 1st class Glukhov, the second engine broke down completely on February 3rd, 1941. The next engine was expected to arrive on February 15th, and trials were falling behind schedule. Assembly of the second T-220 lagged behind due to missing parts. In early February 1941, the turret was still at factory #92 where the F-30 gun and its equipment were being installed.
Finally, instead of a V-2SN engine, a 700 hp V-5 arrived from factory #75. By the time it arrived, several important events happened that would change the fate of the T-220.
Grabin did not forget the idea to install a 107 mm gun with ballistics of the divisional M-60 gun in the KV-2 turret. In December of 1940, it became known that the design bureau of factory #92 developed such a gun on their own initiative and is already starting to build it. This gun, indexed F-42, was proposed for installation into the T-220 turret, but was rejected. It was decided that the lighter T-150 would be put into production under the index KV-3. The T-220 prototype would serve as a testbed for the V-5 engine, which would be used on the KV-3. The same thing happened to the V-5 as to the V-2SN: it didn't last long in the T-220.
The fate of the T-220 was sealed in March of 1941. Information on heavy tanks in the German army began to arrive. Information received by Soviet intelligence led to significant increase in activity regarding tanks and tank armament. This activity also touched domestic heavy designs. The T-220 with an 85 mm gun and 100 mm of armour was deemed insufficient. Instead, a new 72 ton KV-3 started development, with the factory index 223. Overall, this tank would be further development of the T-220, with more powerful armament and 120 mm of armour.
Work on the new KV-3 didn't mean that the existing T-220 was forgotten. On the contrary, the prototype was used as much as possible by the Kirov factory as a testbed for parts and assemblies meant for the new tank. A third V-2SN was installed, this one much more reliable than its predecessors. The tank was used to test new road wheels and Vortex air filters. By June 20th, 1941, it travelled a total of 1979 km. As for the other T-220 prototype, Kirov factory only got to it in early June. Assembly went along lazily, and was planned for no earlier than mid-July. This was how the experimental vehicles met the start of the Great Patriotic War.
Battles for Leningrad
All work on the T-220 stopped after the start of the war. The factory began hurriedly producing KV-1s, focusing their efforts on simplifying the design. When evacuation of the factory began, the KV-3 hull was evacuated. As for the T-220s, nobody had time for them. This changed when the Germans reached the city in the fall of 1941 and any tank at all was worth its weight in gold.
Suddenly, people remembered about the T-220s. Since the tanks never fired a shot and one turret was still in Gorkiy at factory #92, the first T-220 had its turret replaced with a stock KV-1 turret with an F-32 76 mm gun. The same turret was installed on the second tank. On October 5th, 1941, tank T-220 with serial number M-220-1 was sent to the 124th Tank Brigade. On October 16th, the second tank was sent there with the index M-220-2.
In November of 1941, the 124th Tank Brigade and the 43rd Infantry Division fought fierce battles near Ust-Tosno. The second T-220 burned up in these battles along with its crew, commanded by Junior Lieutenant Yakhnin. According to memoirs, the tank carried the slogan "For the Motherland!". As for the first prototype, its fate is unknown.
The story of the T-220 could end here, but it goes on. On February 8th, 1943, order #012 regarding assigning crews to the 12th Independent Training Tank Regiment. The eighth tank in the list is... "For the Motherland", serial number 220-2, whose commander was V.V. Strukov.
How could this be? Usually, burned up vehicles could not be repaired, but there are exceptions. It is known that at least several burned up KV-1s were evacuated and kept on fighting. It is also known that 17 tanks from the 124th Tank Brigade were recovered. One of them must have been M-220-2, repaired in the winter of 1942 at factory #371. During repairs, it was equipped with a V-2K engine, serial number 1193-03. The tank no longer had any worth as a combat vehicle, but it worked as a hands-on training aid for tankers until 1944.
The last episode in the life of the T-220 was the use of its turret. In September of 1941, the turret was replaced with a production KV-1 turret. The tankless turret was found a home. It was installed on a concrete foundation in the 22nd Karelian Fortified Region. The result was called Artillery BOT (KV) with 85 mm gun "Victory". Here, the turret survived the whole war.
Original article by Yuri Pasholok.
Friday, 8 January 2016
Unlucky Seven
Soviet post-war Object 752 and Object 777 heavy tanks were, for their time, the height of daring and originality. The designers had to strike a balance between requirements to increase armour and limits on mass. These restrictions resulted in very compact and well protected tanks with a dense, but reasonable layout. However, the era of heavy tanks was over, and these excellent designs did not move past the model stage.
Replacement Tank
Experience with the IS-4 and IS-7 turned up one unpleasant fact: no matter how perfect your tank is, a weight of over 50 tons is a one way ticket to nowhere. There were several reasons why the IS-7 did not make it into production, but its mass of almost 70 tons isn't the least important. Instead, SKB-2 and NII-100 joined forced to develop a 50-ton tank that combined the progressive solutions of the IS-4 and IS-7. This tank was indexed Object 730, the improved tank received the index IS-8, and the tank was put into production under the index T-10.
The T-10 was less protected than the IS-7 and had an inferior gun, but there weren't any unusual problems that arose when the tank was adopted to replace the IS-2 and IS-3 on December 15th, 1953.
Even while the IS-8 was undergoing trials, talk started regarding its replacement. Such an arrangement might come as a surprise to come, but there is nothing strange here. The late 1940s and the 1950s were a time of rapid development in technologies, plus the Korean War served as an additional boost for tank designers, showing that no pause in tank growth is coming.
While tanks were being built abroad to fight the IS-3 that so impressed the Western viewers of the parade in Berlin, the USSR managed to go through two generations of heavy tanks. Perhaps it would be the right move to drive a few IS-7s down Red Square and provoke the West to create armoured beasts in return, but nobody was thinking of informational warfare. The army needed real tanks.
Research of organizations like NII-48, which studied armour, encouraged a change in generations. The employees of this institute designed a series of solutions that allowed to drastically improve levels of protection without significant increase to weight. This included the "pike nose", variable thickness castings, V-shaped hulls. The T-10 looked obsolete in an instant. Yes, it had a series of novel solutions from the IS-3 and IS-7, but these were solutions from the 1940s.
The artillerymen did not sit still either. For several reasons, the IS-8 received the D-25T gun, which the military was already dissatisfied with in 1944. Additionally, Soviet intelligence carefully tracked the tanks built by potential foes, including the T43 (future M103 Heavy Tank). A successor to the IS-8 was necessary.
Work on creation of a new tank was initiated by the Ministry of Transportation Machinery in late June of 1952. SKB-2 from ChKZ under the direction of M.F. Balzhi was chosen as the developer. In February of 1953, he was replaced with P.P. Isakov. The first drafts were ready by the end of 1952, and in June of 1953, a year after being given this task, SKB-2 presented their project. Or rather projects, since at this point there were two designs. One, Object 752, was developed within the IS-3's mass range. The other, Object 777, was limited by the IS-8's mass.
From the start, SKB-2 was faced with a very difficult issue: creating a tank that, while being lighter than 50 tons, would be superior to the IS-8 in every way. Similar problems were solved before: remember the IS-3 that was significantly better protected than the IS-2. The situation repeated itself, thanks to new scientific achievements made by hull designers.
A new concept of armour was used when designing the Object 752 and Object 777, a landmark in armour technology. In these tanks, different armour plates were not only different thicknesses, but the plates themselves changed thickness. This allowed the designers to achieve unprecedented levels of armour protection while staying within mass limits.
Object 752
The Object 752 was a lot more conventional than its heavier brother, but still very interesting. The dense layout resulted in the tank being only 2300 mm tall (150 mm lower than the IS-8). Recall that this is a fully fledged heavy tank. If in the West, medium tanks already approached (and in the Centurion's case, crossed) the 50 ton barrier by 1950, the Soviet classifications did not change, and the 45.3 ton tank remained a heavy.
From a technical standpoint, the Object 752 had nothing revolutionary about it. It was a classic Soviet heavy tank with six road wheels per side on a torsion bar suspension with a rear engine and hydraulic transmission. The tank was powered by an 800 hp V-12-6 engine used on the IS-8.
According to calculations, the top speed of the tank was 50 kph, with an average speed off-road of 30 kph. The suspension was interesting, as there was a proposal to use a hydraulic suspension with road wheels reminiscent of the IS-7's.
The hull design was much more interesting. The work of hull designers was already highlighted in this article, and for a good reason. Thanks to the new hull design, the Object 752 had equivalent, and in places superior, armour compared to the IS-7. The front of the hull had 215 mm of armour, more than the German Maus and E-100 tanks. Remember that this is a tank that weighed only 45.3 tons.
These mind-boggling results were achieved through the use of casting that allowed variable thickness parts to be made. The thinnest part of the upper front plate was only 90 mm thick, but it was placed at such an angle that it would only be penetrable from a nosedive. The sides were 125 mm thick, but placed at such angles that they guaranteed complete protection from the 88 mm Pak 43. The angles were reasonable enough to leave plenty of room inside for equipment, which was better than NII-100's designs, whose sloped sides often caused layout issues. The turret of the Object 752 was more conventional, and similar to the IS-8's turret. The front part was 260 mm thick, the sides 150 mm thick.
The armament was also revolutionary. The main gun was the 122 mm M-62-2T gun with a muzzle velocity of 950 m/s. This tank was the first where this gun was used. Due to the dense layout, there was no coaxial machinegun. A collapsible mount with a 14.5 mm KPVT machinegun was mounted on the roof by the loader's hatch to protect the tank from low flying aircraft.
The creators of the Object 752 included a loading mechanism. This was not a fully automatic loader, but it noticeably sped up the loading process. Despite the densely packed fighting compartment, there was room for 40 122 mm shells, 10 more than in the IS-8. There was also an alternative proposal with an almost completely automatic loading mechanism. In this case, 28 shells fit along the turret's perimeter (15 AP and 13 HE), and the loader only had to pass in the shells. Drawbacks included less ammunition and a more crowded fighting compartment.
There was an alternative armament proposal, a much more original one. Instead of an IS-8 type turret, SKB-2 designed one that resembled AMX-13 and AMX-50 turrets. The degree of influence of French projects on this design is questionable, but it's doubtful that the public demonstration of the AMX-50 in July of 1951 was ignored by Soviet intelligence.
To be fair, the two turrets only share the general concept. SKB-2 shied away from drum type canisters and only implemented a partially automated loading system, keeping the loader in place. The internal volume of the turret decreased. Interestingly enough, the oscillating turret did not have an AA machinegun, but the coaxial SG-43 machinegun returned. With this new turret, the Object 752 was only 2150 mm tall, lower than a T-26.
Object 777
The heavier Object 777 was a much more revolutionary design than its brother. Judging by the presentation, this was the more promoted project. Unlike the Object 752, where the use of existing components was encouraged, the Object 777 was much more conceptual.
There were two options for the engine, liquid cooled and air cooled. Both projects, indexed V-7, were designed by the ChKZ diesel engine design bureau under the supervision of I.Ya. Trashutin. The air cooled variant was considered higher priority, as it was smaller.
To compare, the length of the IS-8's engine compartment was 3480 mm, the Object 752's was 2410 mm, and the Object 777's was only 2300 for the liquid variant and 2100 for the air cooled variant. Such a drastic reduction in length was possible due to positioning the engine perpendicularly, a first for heavy tanks. As a result, the turret could be moved closer to the center, which had a positive impact on the tank's balance and precision of shooting, especially on the move.
The engine was only one new feature of the tank. With a mass of 49,800 kg, it combined a large amount of innovative solutions. The lighter Object 752 was very low for a heavy tank, but the Object 777 was even lower. The height of the turret hatches was 2100 mm, even less than the T-64, T-72, and T-80.
Thanks to a more powerful engine (850 hp), the speed of the tank was at the level of the Object 752, but with a smoother ride. The smoothness was achieved by lengthening the suspension by one road wheel and a superior weight distribution. The tank also had several variants of hydraulic suspensions, as well as a torsion bar and hydropneumatic suspension. In addition, the tank had a planetary 7-speed gearbox.
The hull of the Object 777 was similar to the Object 752, but there were some notable changes. The maximum thickness of the UFP was reduced to 175 mm, but at a sharper angle, which reduced the weight while retaining the level of protection. As with the Object 752, the driver's seat was shifted slightly to the left. This made entering the vehicle easier and made it harder for the driver to his his head on the gun when his seat was fixed in the travel position.
The liquid and air cooled variants differed externally. The roof of the engine compartment had an air intake for the centrifugal air filter. As for the water cooled variant, it had a different shape of the rear and roof to accommodate the larger radiator.
The turret was similar to that of the Object 752, but with some changes. The front was only 195 mm thick, but due to a more extreme slope, it retained the same level of protection. The sides were 215 mm thick, making them impenetrable for the German 128 mm gun used on the Maus. The mechanical loader was not used. The Object 777 kept the coaxial SG-43 machinegun. The liquid cooled variant had the same AA mount as the Object 752, but the air cooled tank got a remote controlled AA turret on top of the main turret.
Both projects were sent to the Ministry of Transportation Machinery in June of 1953. After some discussion, the layout of the Object 777 was changed. A wooden 1:10 scale model was also made. Work on this very interesting project continued until 1954, but sadly, did not progress past models.
However, the effort did not go to waste. Solutions used in these projects went on to be used in the Object 770 tank. The shape of the hull and turret are reminiscent of its predecessor. Additionally, the experience was used to modernize the IS-8/T-10. In 1957, the T-10M entered production, armed with the 122 mm M-62 gun.
Original article by Yuri Pasholok.
Replacement Tank
Experience with the IS-4 and IS-7 turned up one unpleasant fact: no matter how perfect your tank is, a weight of over 50 tons is a one way ticket to nowhere. There were several reasons why the IS-7 did not make it into production, but its mass of almost 70 tons isn't the least important. Instead, SKB-2 and NII-100 joined forced to develop a 50-ton tank that combined the progressive solutions of the IS-4 and IS-7. This tank was indexed Object 730, the improved tank received the index IS-8, and the tank was put into production under the index T-10.
The T-10 was less protected than the IS-7 and had an inferior gun, but there weren't any unusual problems that arose when the tank was adopted to replace the IS-2 and IS-3 on December 15th, 1953.
Even while the IS-8 was undergoing trials, talk started regarding its replacement. Such an arrangement might come as a surprise to come, but there is nothing strange here. The late 1940s and the 1950s were a time of rapid development in technologies, plus the Korean War served as an additional boost for tank designers, showing that no pause in tank growth is coming.
While tanks were being built abroad to fight the IS-3 that so impressed the Western viewers of the parade in Berlin, the USSR managed to go through two generations of heavy tanks. Perhaps it would be the right move to drive a few IS-7s down Red Square and provoke the West to create armoured beasts in return, but nobody was thinking of informational warfare. The army needed real tanks.
Research of organizations like NII-48, which studied armour, encouraged a change in generations. The employees of this institute designed a series of solutions that allowed to drastically improve levels of protection without significant increase to weight. This included the "pike nose", variable thickness castings, V-shaped hulls. The T-10 looked obsolete in an instant. Yes, it had a series of novel solutions from the IS-3 and IS-7, but these were solutions from the 1940s.
The artillerymen did not sit still either. For several reasons, the IS-8 received the D-25T gun, which the military was already dissatisfied with in 1944. Additionally, Soviet intelligence carefully tracked the tanks built by potential foes, including the T43 (future M103 Heavy Tank). A successor to the IS-8 was necessary.
Work on creation of a new tank was initiated by the Ministry of Transportation Machinery in late June of 1952. SKB-2 from ChKZ under the direction of M.F. Balzhi was chosen as the developer. In February of 1953, he was replaced with P.P. Isakov. The first drafts were ready by the end of 1952, and in June of 1953, a year after being given this task, SKB-2 presented their project. Or rather projects, since at this point there were two designs. One, Object 752, was developed within the IS-3's mass range. The other, Object 777, was limited by the IS-8's mass.
From the start, SKB-2 was faced with a very difficult issue: creating a tank that, while being lighter than 50 tons, would be superior to the IS-8 in every way. Similar problems were solved before: remember the IS-3 that was significantly better protected than the IS-2. The situation repeated itself, thanks to new scientific achievements made by hull designers.
A new concept of armour was used when designing the Object 752 and Object 777, a landmark in armour technology. In these tanks, different armour plates were not only different thicknesses, but the plates themselves changed thickness. This allowed the designers to achieve unprecedented levels of armour protection while staying within mass limits.
Object 752
The Object 752 was a lot more conventional than its heavier brother, but still very interesting. The dense layout resulted in the tank being only 2300 mm tall (150 mm lower than the IS-8). Recall that this is a fully fledged heavy tank. If in the West, medium tanks already approached (and in the Centurion's case, crossed) the 50 ton barrier by 1950, the Soviet classifications did not change, and the 45.3 ton tank remained a heavy.
From a technical standpoint, the Object 752 had nothing revolutionary about it. It was a classic Soviet heavy tank with six road wheels per side on a torsion bar suspension with a rear engine and hydraulic transmission. The tank was powered by an 800 hp V-12-6 engine used on the IS-8.
According to calculations, the top speed of the tank was 50 kph, with an average speed off-road of 30 kph. The suspension was interesting, as there was a proposal to use a hydraulic suspension with road wheels reminiscent of the IS-7's.
The hull design was much more interesting. The work of hull designers was already highlighted in this article, and for a good reason. Thanks to the new hull design, the Object 752 had equivalent, and in places superior, armour compared to the IS-7. The front of the hull had 215 mm of armour, more than the German Maus and E-100 tanks. Remember that this is a tank that weighed only 45.3 tons.
These mind-boggling results were achieved through the use of casting that allowed variable thickness parts to be made. The thinnest part of the upper front plate was only 90 mm thick, but it was placed at such an angle that it would only be penetrable from a nosedive. The sides were 125 mm thick, but placed at such angles that they guaranteed complete protection from the 88 mm Pak 43. The angles were reasonable enough to leave plenty of room inside for equipment, which was better than NII-100's designs, whose sloped sides often caused layout issues. The turret of the Object 752 was more conventional, and similar to the IS-8's turret. The front part was 260 mm thick, the sides 150 mm thick.
The armament was also revolutionary. The main gun was the 122 mm M-62-2T gun with a muzzle velocity of 950 m/s. This tank was the first where this gun was used. Due to the dense layout, there was no coaxial machinegun. A collapsible mount with a 14.5 mm KPVT machinegun was mounted on the roof by the loader's hatch to protect the tank from low flying aircraft.
The creators of the Object 752 included a loading mechanism. This was not a fully automatic loader, but it noticeably sped up the loading process. Despite the densely packed fighting compartment, there was room for 40 122 mm shells, 10 more than in the IS-8. There was also an alternative proposal with an almost completely automatic loading mechanism. In this case, 28 shells fit along the turret's perimeter (15 AP and 13 HE), and the loader only had to pass in the shells. Drawbacks included less ammunition and a more crowded fighting compartment.
There was an alternative armament proposal, a much more original one. Instead of an IS-8 type turret, SKB-2 designed one that resembled AMX-13 and AMX-50 turrets. The degree of influence of French projects on this design is questionable, but it's doubtful that the public demonstration of the AMX-50 in July of 1951 was ignored by Soviet intelligence.
To be fair, the two turrets only share the general concept. SKB-2 shied away from drum type canisters and only implemented a partially automated loading system, keeping the loader in place. The internal volume of the turret decreased. Interestingly enough, the oscillating turret did not have an AA machinegun, but the coaxial SG-43 machinegun returned. With this new turret, the Object 752 was only 2150 mm tall, lower than a T-26.
Object 777
The heavier Object 777 was a much more revolutionary design than its brother. Judging by the presentation, this was the more promoted project. Unlike the Object 752, where the use of existing components was encouraged, the Object 777 was much more conceptual.
There were two options for the engine, liquid cooled and air cooled. Both projects, indexed V-7, were designed by the ChKZ diesel engine design bureau under the supervision of I.Ya. Trashutin. The air cooled variant was considered higher priority, as it was smaller.
To compare, the length of the IS-8's engine compartment was 3480 mm, the Object 752's was 2410 mm, and the Object 777's was only 2300 for the liquid variant and 2100 for the air cooled variant. Such a drastic reduction in length was possible due to positioning the engine perpendicularly, a first for heavy tanks. As a result, the turret could be moved closer to the center, which had a positive impact on the tank's balance and precision of shooting, especially on the move.
The engine was only one new feature of the tank. With a mass of 49,800 kg, it combined a large amount of innovative solutions. The lighter Object 752 was very low for a heavy tank, but the Object 777 was even lower. The height of the turret hatches was 2100 mm, even less than the T-64, T-72, and T-80.
Thanks to a more powerful engine (850 hp), the speed of the tank was at the level of the Object 752, but with a smoother ride. The smoothness was achieved by lengthening the suspension by one road wheel and a superior weight distribution. The tank also had several variants of hydraulic suspensions, as well as a torsion bar and hydropneumatic suspension. In addition, the tank had a planetary 7-speed gearbox.
The hull of the Object 777 was similar to the Object 752, but there were some notable changes. The maximum thickness of the UFP was reduced to 175 mm, but at a sharper angle, which reduced the weight while retaining the level of protection. As with the Object 752, the driver's seat was shifted slightly to the left. This made entering the vehicle easier and made it harder for the driver to his his head on the gun when his seat was fixed in the travel position.
The liquid and air cooled variants differed externally. The roof of the engine compartment had an air intake for the centrifugal air filter. As for the water cooled variant, it had a different shape of the rear and roof to accommodate the larger radiator.
The turret was similar to that of the Object 752, but with some changes. The front was only 195 mm thick, but due to a more extreme slope, it retained the same level of protection. The sides were 215 mm thick, making them impenetrable for the German 128 mm gun used on the Maus. The mechanical loader was not used. The Object 777 kept the coaxial SG-43 machinegun. The liquid cooled variant had the same AA mount as the Object 752, but the air cooled tank got a remote controlled AA turret on top of the main turret.
Both projects were sent to the Ministry of Transportation Machinery in June of 1953. After some discussion, the layout of the Object 777 was changed. A wooden 1:10 scale model was also made. Work on this very interesting project continued until 1954, but sadly, did not progress past models.
However, the effort did not go to waste. Solutions used in these projects went on to be used in the Object 770 tank. The shape of the hull and turret are reminiscent of its predecessor. Additionally, the experience was used to modernize the IS-8/T-10. In 1957, the T-10M entered production, armed with the 122 mm M-62 gun.
Original article by Yuri Pasholok.
Thursday, 7 January 2016
Too Much Power
"To comrade Stalin
GOKO decree issued on March 12th, 1944 #5378ss accepted the 580 hp V-11 diesel engine, to be installed in the IS tank. Preparations for production of these diesel engines is complete, however due to the poor suitability of production IS tanks for an increased power engine, only 150 V-11 engines were made instead of the 720 ordered by the decree.
The People's Commissariat of Tank Production is currently modernizing IS tanks and SPGs in order to be able to use the 580 hp V-11 diesel engine.
Considering the improved reliability of the V-11 engine compared to the V-2 engine, we ask you to permit the NKTP to produce IS tanks and SPGs with 520 hp V-11 diesel engines until the modernization is complete.
A draft of the GOKO decree is provided for your approval.
L. Beria
V. Malyshev
Ya. Fedorenko."
RGASPI 644-2-395
GOKO decree issued on March 12th, 1944 #5378ss accepted the 580 hp V-11 diesel engine, to be installed in the IS tank. Preparations for production of these diesel engines is complete, however due to the poor suitability of production IS tanks for an increased power engine, only 150 V-11 engines were made instead of the 720 ordered by the decree.
The People's Commissariat of Tank Production is currently modernizing IS tanks and SPGs in order to be able to use the 580 hp V-11 diesel engine.
Considering the improved reliability of the V-11 engine compared to the V-2 engine, we ask you to permit the NKTP to produce IS tanks and SPGs with 520 hp V-11 diesel engines until the modernization is complete.
A draft of the GOKO decree is provided for your approval.
L. Beria
V. Malyshev
Ya. Fedorenko."
RGASPI 644-2-395
Wednesday, 6 January 2016
How the LTTB Was Born
Light tanks made during the Great Patriotic War were cheap and simple vehicles, capable of being put into mass production in the most difficult conditions. By 1943, Soviet industry was restored, but the need of a good light tank did not go anywhere. Design bureaus got to work, and by 1944 they had a tank that was difficult to call anything but "light tank with heavy armour". This is the name that the tank was given when it was modelled for World of Tanks.
Tuesday, 5 January 2016
German Reload Rates
I covered how the Red Army calculated its reload rates here. To summarize, the test is quite grueling: the rate of fire calculations involve extracting the shell between each shot, re-adjusting the aim if knocked off, and loading from all ammunition racks present in the tank. The result, however, is quite reliable, a figure that you can be certain your tank can achieve in combat, provided the tank commander is aware of his targets.
Now, for the Germans. Thankfully, British trials (WO291/1003 Motion studies of German Tanks) left us a plethora of materials on testing German trophies in the most minute details. Let's take a look at one of their tests, that of the Tiger.
Now, for the Germans. Thankfully, British trials (WO291/1003 Motion studies of German Tanks) left us a plethora of materials on testing German trophies in the most minute details. Let's take a look at one of their tests, that of the Tiger.
As you can see, the sequence of actions is quite limited and only involved retrieving the round from the ammunition rack and placing it into the breech. No extraction or firing is performed. Here is the full spectrum of loading trials:
Loading the first four rounds takes about 7-8 seconds each in the more favourable positions. Very few rounds can be loaded in a sliver under 6 seconds. As the loader uses up the shells that are closest to him, the amount of time needed to load a shell increases drastically. Based on this information, can you guess that the rate of fire of the Tiger was recorded as?
10 RPM. It appears that the data was extrapolated from the loading of a single shell in optimal conditions, something that in no way represents the rate of fire of a vehicle in combat.
Conveniently, the rate of fire for the Tiger II is right there, so let's take a look at what the British discovered. These are tests of the ready racks only, the ones that are most readily accessible.
Even from the best of racks, the long shell of the KwK 43 made loading the gun a difficult chore. You can see that it takes 8-10 seconds to load a shell, resulting in a maximum theoretical rate of fire of 6-7.5 RPM. In Soviet trials, the Tiger II scored a maximum of 5.7 RPM, which is reasonable, considering the addition of the extra overhead of actually firing the gun. However, as you can see from the above table, the Germans gave their Tiger II a rate of fire of 6-10 RPM, significantly higher than practical trials suggest is actually possible.
Monday, 4 January 2016
Kirov Factory 1941-1945
Any company likes to toot its horn about its accomplishments, and the Kirov Factory is no exception. Here are posters commemorating their work during the Great Patriotic War:
"Kirov factory in the Patriotic War. Ural, 1941-1945"
"During the war, the factory created 13 types of heavy tanks and SPGs.
- KV-2 tank, 1940, before the war.
- KV-1 tank, 2371 produced in 1941-1942
- KV-1S tank, 1106 produced in 1942-1943
- KV-8 flamethrower tank, 42 produced in 1942
- KV-8S flamethrower tank, 25 produced in 1942
- SU-152, 671 produced in 1942-1943
- KV-85 tank, 148 produced in 1943
- T-34 tank designed at factory #183, 5094 produced
- IS-85 tank, 107 produced in 1943
- ISU-152, 1875 produced in 1943-1945
- ISU-122, 1435 produced in 1944-1945
- ISU-122S, 475 produced in 1944-1945
- IS-2 tank, 3380 produced in 1944-1945
- IS-3 tank, 130 produced in 1945
- 701 tank, 1944-1945, recommended for adoption by the army
In total, the factory built 16859 tanks and SPGs during the war."
Sunday, 3 January 2016
World of Tanks Armoured Fantasy: Screw Drive
The idea of a tank without tracks and wheels sounds absurd. Even more absurd is the idea of a vehicle driven by something that looks like a huge screw affixed under the hull. And yet, among the many ideas sent to the Department of Inventions, the screw drive was one of the most reasonable and viable.
Grigorenko's "Driving Worm Gear"
On May 9th, 1944, exactly one year before Victory Day, Guards Senior Technical Lieutenant Boris Grigorenko deposited his invention into a field post box. The address was brief: "Moscow - Kremlin". The author proposed a new type of suspension that would not be troubled by "loose mud, swamps with vegetation, rivers, lakes, sands, snows, and others". He asked for help in building his prototype and testing it against the fascists.
Grigorenko called his implementation of Archimedes' Screw a "Driving Worm Gear". The vehicle would be driven by solid metallic rods with a threaded surface. "The driving worm gear is a replacement for wheels, tracks, bogeys. When the worm gear spins, the tank moves forward due to its thread". According to the author, this would give the tank optimal off-road performance. Grigorenko also included shock absorbers for travelling on a paved surface, adding rubber rollers.
He admitted to being an amateur: "I am not a technician or a draftsman, and I do not have the opportunity to schematically describe everything on paper." The author hoped that the idea would be worked on in Moscow by specialists and that he would be invited to supervise.
Grigorenko wrote little about the details of his invention, but included a few simple sketches. He proposed several variants of his worm gear. The first was an all terrain vehicle with a boat-like shape. The engine and transmission were in the front, along with the front deck and the driver's cabin, covered in glass, according to the sketch. A tarp covered platform behind it could hold up to 2 tons of cargo. Next, the author drew a GAZ-AA truck, replacing the rear wheels with his worm gear. The only techncial specification he wrote on the sketch was "Yaroslavl rubber factory USSR" on the tire. Lastly, the "driving worm gear" could be used on a tank, but that sketch was very abstract and had no comments at all.
The response of professionals is not known, as it was not preserved in the archives.
Beketov's Screw Tank
Engineering technologist V. Beketov made more progress in this area. In August of 1942, he sent his screw tank project to GABTU's Department of Inventions.
The description of the vehicle was prefaced with a discussion of what the ideal tank should be like. High firepower, speed, maneuverability, stability, but most importantly, a lack of weak points. The weakness of all tanks is the running gear, and Beketov thought he found a way to make it safe. "The main idea for solving this issue is a running gear that is, itself, a part of the armoured hull." The inventor proposed a vehicle that, in itself, was one big running gear. Instead of a tracked vehicle, he made a screw-driven one.
Beketov's tank consisted of a hollow armoured cylinder with an engine compartment and a driver's compartment inside. The rapidly spinning cylinder would propel the tank, but this was not enough according to the author. He wrote: "This idea is realistic only if two armoured cylinders are rigidly connected together and spin in opposite directions." The tank would be made out of steel pipes of various sizes and lengths.
Two of them, making up the hull, were 6.2 meters long and 1.2 meters in diameter. The minimum thickness of the armoured walls was only 10 mm. The pipes ended with cones. Four thickly walled pipes connected the two halves, and two more allowed the crew to travel between them.
The cylinders were split up into parts with bulkheads. "The bulkheads separate the compartments: engine, combat, and control. Aside from that, they make the cylinders more robust." In an attempt to decentralize the important parts of the vehicle, Beketov put the engines in the center. The engine compartment would be accessible from both sides. The author proposed installing the engine on a special metal frame. Fuel and oil would be stored underneath it. The fighting compartments were located under each of the four turrets. The author did not specify which turrets he would use, only that they would have 45 mm guns and machineguns. "The use of four turrets allows for the possibility of powerful defensive fire. Two turrets can fire per side, and when necessary, three or even all four turrets can be aimed at the same target."
The main feature of the design was the screw drive. The author wrote much about its benefits, such as the automatic adjustment of the ground pressure. It would be minimized when moving on snow or swamps, but maximized on hard surfaces.
Beketov described the characteristics of his creation in great detail: 7 meter long hull, 2.3 meters tall, 3 meters wide, and weighing 28 tons. This mass was not surprising considering the conservative armour thickness. A duo of 250 hp aircraft engines would propel the tank to a speed of up to 50 kph. GABTU's response to this project is also not known.
Sending their ideas for review, both inventors thought they made a discovery. Meanwhile, the idea of a screw drive was older than both of them. The first prototypes of screw driven vehicles were built in the 19th century, and in 1900 inventor Franz Dergint received a patent for a sled propelled by screws.
A whole series of screw driven all terrain vehicles was made after WWII. Some of them are still used today, irreplaceable for search and rescue missions in difficult terrain. This means that some fantasies can be made a reality and used to help people.
Original article available here.
Grigorenko's "Driving Worm Gear"
On May 9th, 1944, exactly one year before Victory Day, Guards Senior Technical Lieutenant Boris Grigorenko deposited his invention into a field post box. The address was brief: "Moscow - Kremlin". The author proposed a new type of suspension that would not be troubled by "loose mud, swamps with vegetation, rivers, lakes, sands, snows, and others". He asked for help in building his prototype and testing it against the fascists.
Grigorenko called his implementation of Archimedes' Screw a "Driving Worm Gear". The vehicle would be driven by solid metallic rods with a threaded surface. "The driving worm gear is a replacement for wheels, tracks, bogeys. When the worm gear spins, the tank moves forward due to its thread". According to the author, this would give the tank optimal off-road performance. Grigorenko also included shock absorbers for travelling on a paved surface, adding rubber rollers.
He admitted to being an amateur: "I am not a technician or a draftsman, and I do not have the opportunity to schematically describe everything on paper." The author hoped that the idea would be worked on in Moscow by specialists and that he would be invited to supervise.
Grigorenko wrote little about the details of his invention, but included a few simple sketches. He proposed several variants of his worm gear. The first was an all terrain vehicle with a boat-like shape. The engine and transmission were in the front, along with the front deck and the driver's cabin, covered in glass, according to the sketch. A tarp covered platform behind it could hold up to 2 tons of cargo. Next, the author drew a GAZ-AA truck, replacing the rear wheels with his worm gear. The only techncial specification he wrote on the sketch was "Yaroslavl rubber factory USSR" on the tire. Lastly, the "driving worm gear" could be used on a tank, but that sketch was very abstract and had no comments at all.
The response of professionals is not known, as it was not preserved in the archives.
Beketov's Screw Tank
Engineering technologist V. Beketov made more progress in this area. In August of 1942, he sent his screw tank project to GABTU's Department of Inventions.
The description of the vehicle was prefaced with a discussion of what the ideal tank should be like. High firepower, speed, maneuverability, stability, but most importantly, a lack of weak points. The weakness of all tanks is the running gear, and Beketov thought he found a way to make it safe. "The main idea for solving this issue is a running gear that is, itself, a part of the armoured hull." The inventor proposed a vehicle that, in itself, was one big running gear. Instead of a tracked vehicle, he made a screw-driven one.
Beketov's tank consisted of a hollow armoured cylinder with an engine compartment and a driver's compartment inside. The rapidly spinning cylinder would propel the tank, but this was not enough according to the author. He wrote: "This idea is realistic only if two armoured cylinders are rigidly connected together and spin in opposite directions." The tank would be made out of steel pipes of various sizes and lengths.
Two of them, making up the hull, were 6.2 meters long and 1.2 meters in diameter. The minimum thickness of the armoured walls was only 10 mm. The pipes ended with cones. Four thickly walled pipes connected the two halves, and two more allowed the crew to travel between them.
The cylinders were split up into parts with bulkheads. "The bulkheads separate the compartments: engine, combat, and control. Aside from that, they make the cylinders more robust." In an attempt to decentralize the important parts of the vehicle, Beketov put the engines in the center. The engine compartment would be accessible from both sides. The author proposed installing the engine on a special metal frame. Fuel and oil would be stored underneath it. The fighting compartments were located under each of the four turrets. The author did not specify which turrets he would use, only that they would have 45 mm guns and machineguns. "The use of four turrets allows for the possibility of powerful defensive fire. Two turrets can fire per side, and when necessary, three or even all four turrets can be aimed at the same target."
The main feature of the design was the screw drive. The author wrote much about its benefits, such as the automatic adjustment of the ground pressure. It would be minimized when moving on snow or swamps, but maximized on hard surfaces.
Beketov described the characteristics of his creation in great detail: 7 meter long hull, 2.3 meters tall, 3 meters wide, and weighing 28 tons. This mass was not surprising considering the conservative armour thickness. A duo of 250 hp aircraft engines would propel the tank to a speed of up to 50 kph. GABTU's response to this project is also not known.
Sending their ideas for review, both inventors thought they made a discovery. Meanwhile, the idea of a screw drive was older than both of them. The first prototypes of screw driven vehicles were built in the 19th century, and in 1900 inventor Franz Dergint received a patent for a sled propelled by screws.
A whole series of screw driven all terrain vehicles was made after WWII. Some of them are still used today, irreplaceable for search and rescue missions in difficult terrain. This means that some fantasies can be made a reality and used to help people.
Original article available here.
Saturday, 2 January 2016
World of Tanks History Section: 43M. Toldi III
In the 1930s, Hungary took its time to pick a tank for its army. At first, the kingdom received L3/L5 tankettes from Italy. After that, Hungary started thinking about producing its own tank, as the country's industrial base was powerful enough for such a task. As many European countries, the initial plan was to build a convertible drive tank, this one designed by Miklos Straussler. However, after trials in 1937, the decision was made to produce the Swedish light Lansverk L-60 tank.
At the time, the L-60 could be considered the best tank in the world. The tank was fast, comfortable, easy to produce. Otto Merker's tank stood head and shoulders above its competitors. It was the first tank in the world to use a torsion bar suspension. The L-60 was initially armed with a 20 mm Madsen autocannon.
In Hungary, the L-60 was initially indexed 38M. Toldi I or Toldi A20. A series of modifications were made before mass production in 1940. The Swedish engine was replaced with a German Bussing engine, and a 36M anti-tank rifle was used instead of the 20 mm cannon. When the Hungarians trialled the 37 mm Bofors cannon, much more suitable for fighting tanks, it was also converted for installation in the L-60. The initial order for 80 tanks was split between Ganz and MAVAG companies in Budapest. After that, 110 tanks from the second series were ordered, indexed 38M. Toldi II or Toldi B20. These tanks had thicker armour, more domestic components, and a new radio.
However time did not stand still, and requirements for tanks changed. In the summer of 1941, the Hungarians encountered their first problems.
The L-60 was made to fight light tanks from the late 1930s with a maximum of 20 mm of armour. The 20 mm autocannon could deal with them. Now, Hungary's enemy was the USSR, whose thinly armoured T-26, T-28, and BT tanks were largely lost in the summer of 1941. T-34s and KVs were built to replace them, against which a 20 mm shell or an anti-tank rifle bullet was useless. Even wartime Soviet light tanks like the T-60 and T-70 were too much for the Toldi, while the 45 mm gun on the T-70 could effortlessly knock it out in return.
The military started thinking about doing something with the armament in early 1942. This task was somewhat simplified by the new medium 40M. Turan tank. Its 40 mm gun was shortened and equipped with a muzzle brake. The 38M. Toldi IIA was born. It was not produced separately, but instead, existing tanks were modernized to the new standard. 80 vehicles were converted in total.
This was only a half-measure. The Hungarian army lost many tanks on the Eastern Front, and they needed a way to rebuild their tank army.
In 1943, Hungarian engineers developed a new tank that would replace the 38M. as the new light tank. The new tank was indexed 43M. Toldi III (Toldi C40). Its armour remained at the level of its predecessor, but could be equipped with side skirts, tested on the Toldi IIA. They could not save the tank from shells, but were a serious impediment to infantry anti-tank rifles.
The 43M. Toldi III was supposed to be produced at Ganz factories. Production began in 1944, but only 12 vehicles were finished. On July 2nd, 1944, Allied aircraft delivered a massive bomb strike on Budapest, which crippled Ganz factories. Thus, the story of Hungarian light tanks ends.
Even if bombs did not bring an end to the Toldi III, it was unable to fight any Soviet tank in 1943, while being penetrable by any anti-tank gun from any angle. The designers of the 43M. Toldi III were at least two years too late.
Original article available here.
At the time, the L-60 could be considered the best tank in the world. The tank was fast, comfortable, easy to produce. Otto Merker's tank stood head and shoulders above its competitors. It was the first tank in the world to use a torsion bar suspension. The L-60 was initially armed with a 20 mm Madsen autocannon.
In Hungary, the L-60 was initially indexed 38M. Toldi I or Toldi A20. A series of modifications were made before mass production in 1940. The Swedish engine was replaced with a German Bussing engine, and a 36M anti-tank rifle was used instead of the 20 mm cannon. When the Hungarians trialled the 37 mm Bofors cannon, much more suitable for fighting tanks, it was also converted for installation in the L-60. The initial order for 80 tanks was split between Ganz and MAVAG companies in Budapest. After that, 110 tanks from the second series were ordered, indexed 38M. Toldi II or Toldi B20. These tanks had thicker armour, more domestic components, and a new radio.
However time did not stand still, and requirements for tanks changed. In the summer of 1941, the Hungarians encountered their first problems.
The L-60 was made to fight light tanks from the late 1930s with a maximum of 20 mm of armour. The 20 mm autocannon could deal with them. Now, Hungary's enemy was the USSR, whose thinly armoured T-26, T-28, and BT tanks were largely lost in the summer of 1941. T-34s and KVs were built to replace them, against which a 20 mm shell or an anti-tank rifle bullet was useless. Even wartime Soviet light tanks like the T-60 and T-70 were too much for the Toldi, while the 45 mm gun on the T-70 could effortlessly knock it out in return.
The military started thinking about doing something with the armament in early 1942. This task was somewhat simplified by the new medium 40M. Turan tank. Its 40 mm gun was shortened and equipped with a muzzle brake. The 38M. Toldi IIA was born. It was not produced separately, but instead, existing tanks were modernized to the new standard. 80 vehicles were converted in total.
This was only a half-measure. The Hungarian army lost many tanks on the Eastern Front, and they needed a way to rebuild their tank army.
In 1943, Hungarian engineers developed a new tank that would replace the 38M. as the new light tank. The new tank was indexed 43M. Toldi III (Toldi C40). Its armour remained at the level of its predecessor, but could be equipped with side skirts, tested on the Toldi IIA. They could not save the tank from shells, but were a serious impediment to infantry anti-tank rifles.
The 43M. Toldi III was supposed to be produced at Ganz factories. Production began in 1944, but only 12 vehicles were finished. On July 2nd, 1944, Allied aircraft delivered a massive bomb strike on Budapest, which crippled Ganz factories. Thus, the story of Hungarian light tanks ends.
Even if bombs did not bring an end to the Toldi III, it was unable to fight any Soviet tank in 1943, while being penetrable by any anti-tank gun from any angle. The designers of the 43M. Toldi III were at least two years too late.
Original article available here.
Friday, 1 January 2016
Unneeded Scout
The PzII n.A., more commonly known as Luchs, had a competitor developed by BMM (formerly CKD), the Pz38(t) n.A. It was superior in, at the very least, reliability and armament, but the Luchs entered mass production instead. Why did this happen, and what was the light tank developed in occupied Czechoslovakia like?
Supply and demand
The performance of the PzII Ausf. D tank in the Polish Campaign made it clear that the Wehrmacht needs a new light tank. In the middle of September of 1939, even before the fighting was done, the Ministry of Armament and Ammunition sent out an order for a new fast reconnaissance tank.
At first, MAN and Daimler-Benz worked on the project together: the first company was developing the chassis, the second the the turret and turret platform. The project was indexed VK 13.01 (experimental vehicle, 13 ton class, first prototype). It would reach a speed of 70 kph, have a two man turret, armour up to 30 mm, and weigh 11 tons.
New Competitors
In July of 1940, the situation changed. Two competitors emerged that MAN and Daimler-Benz did not think of. In March of 1939, Germany occupied Czechoslovakia and took control of their manufacturing base, including Skoda and Českomoravská Kolben-Daněk (CKD), the chief producers of Czechoslovak armoured vehicles. After the occupation, the factories continued making tanks for their new masters. The factories retained their design bureaus and continued to design new tanks.
BMM finished their scout tank in December of 1941, almost 6 months after MAN (the PzII n.A. was finished in July of 1941), but the headstart was annulled by changes to the requirements. Several major changes were made in 1941 alone, and the grandiose plans of 250 VK 13.03 tanks and lighter VK 9.03 tanks had to be corrected. MAN did not begin production in the fall or winter of 1941. Production of the PzIII was also hampering MAN, and demand for them was at its peak. This played right into the hands of the Czech companies, which caught up to their competitors.
Differences from the old model
The BMM project was first called TNH n.A. (neuer Art, new type), and was not designed from scratch. The design team used their experience in designing the TNH (better known as LT vz 38 or Pz38(t)) extensively. The overall layout and a significant part of the hull migrated to the new design. The engine was in the rear, transmission and drive wheels at the front. At the same time, the tank was anything but a cosmetically altered Pz38(t).
The design bureau didn't waste their two years of development, and the requirements called for serious changes. The 220 hp Praha NR1 V-shaped 8 cylinder engine was chosen for the TNH n.A. The new engine was longer than the old Praha TNHPS/II (a licensed copy of the Swedish Scania-Vabis typ 1664), so the engine compartment had to be enlarged. The suspension looked similar, but looks can be deceiving. The tank was almost a ton heavier, so it too had to be changed. The diameter of the road wheels grew from 775 to 810 mm, and the tracks were widened from 293 to 305 mm. The drive wheel changed too.
Significant changes were made to the hull. Aside from lengthening it, the front was redesigned. The hull machinegun was removed, replaced with a vision block for the radio operator, similar to the one on the PzIII. The driver received the same vision block. The tank's armament consisted of a 37 mm Skoda A-19 gun and a coaxial MG-34. The tank had no commander's cupola, but had a large bump with observation devices on the perimeter.
Special features
It's worth mentioning the technology for the hull and turret of the TNH n.A. Almost all Skoda and BMM vehicles had riveted hulls and turrets. This design has many drawbacks, including secondary fragments caused by rivets flying off when the tank was hit. The TNH n.A. was the first tank at BMM that was fully welded. According to sources, the first tank was riveted and made from mild steel, the second was welded from mild steel, the third was riveted from hardened steel, and the remaining two were welded from hardened steel. According to the plan, BMM produced one prototype per month. The last tank was produced in April of 1942. It's worth noting that no prototype was entirely welded, as the rear and engine compartment doors were still riveted.
The prototypes differed in other ways. The first one had track covers from the Pz38(t). The tank did not receive observation devices, and they were replaced by screens with snow wipers. The tank was equipped with two Notek lights and an automotive horn on the right side of the front plate. The second prototype, with a welded hull and turret, got new track covers. The third prototype was closer to the first one, but received new track covers and a floodlight on the roof. Later, a Tatra Typ 103 220 hp diesel engine was installed on this tank. Like the first prototype, the third received no observation devices. The tank finally reached its final shape with the fourth and fifth prototypes, which received a full set of optics.
Trials and unfair competition
The first vehicle went through a majority of the trials. In late January of 1942, it was shipped to Kummersdorf where it underwent trials alongside the PzII n.A. and the Skoda T-15. Over a few months, the prototype travelled 3866 km without significant breakdowns, which compared favourably to its competitors. It would appear that the Czech tank was winning, but everything was decided during the second stage of the trials in May-June of 1942. The Pz38(t) n.A. and T-15 lost points for having lower clearance and higher fuel consumption. Additionally, the 37 mm gun ate up precious turret room, whereas the PzII n.A. had a more compact 20 mm gun.
The notes in the report suggest that MAN used their administrative powers, especially regarding armament. The author had to know that the 20 mm gun was already unsatisfactory for the German military in March of 1942. In spring of 1942, requirements were made that the PzII n.A. (Pz.Spw.Wg. II Ausf. MAN) had to have a two man turret with a 50 mm gun. This requirement refers to the turret from the VK 16.02, otherwise known as the Gefechts Aufklärer Leopard. Specifications for the Pz.Spw.Wg. II Ausf. BMM were right next to the Pz.Spw.Wg. II Ausf. MAN specifications, and also feature a 50 mm gun in a Daimler-Benz turret. Overlaying the turret over the BMM design shows that this conversion would have been possible. Either way, nothing more than letters and sketches was done on this subject.
The PzII Luchs achieved a Pyrrhic victory. MAN was so full of orders that only 100 of these tanks were produced. If BMM received an order for its Pz38(t) n.A., the situation might have been different. Nevertheless, the experience of designing the tank was not wasted, and the modernized suspension was used for the Jagdpanzer 38(t) tank destroyer.
The prototypes had various fates. The third prototype served as an experimental testbed for the Tatra Typ 103 engine and solutions planned for the TNH-57-900 tank. The final fate of the other tanks is unknown, but at least one tank survived the war. Judging by the track covers, it's the second or third prototype, but the picture quality is so poor that one cannot tell if the tank is riveted or welded.
Original article by Yuri Pasholok.
Supply and demand
The performance of the PzII Ausf. D tank in the Polish Campaign made it clear that the Wehrmacht needs a new light tank. In the middle of September of 1939, even before the fighting was done, the Ministry of Armament and Ammunition sent out an order for a new fast reconnaissance tank.
At first, MAN and Daimler-Benz worked on the project together: the first company was developing the chassis, the second the the turret and turret platform. The project was indexed VK 13.01 (experimental vehicle, 13 ton class, first prototype). It would reach a speed of 70 kph, have a two man turret, armour up to 30 mm, and weigh 11 tons.
New Competitors
In July of 1940, the situation changed. Two competitors emerged that MAN and Daimler-Benz did not think of. In March of 1939, Germany occupied Czechoslovakia and took control of their manufacturing base, including Skoda and Českomoravská Kolben-Daněk (CKD), the chief producers of Czechoslovak armoured vehicles. After the occupation, the factories continued making tanks for their new masters. The factories retained their design bureaus and continued to design new tanks.
BMM finished their scout tank in December of 1941, almost 6 months after MAN (the PzII n.A. was finished in July of 1941), but the headstart was annulled by changes to the requirements. Several major changes were made in 1941 alone, and the grandiose plans of 250 VK 13.03 tanks and lighter VK 9.03 tanks had to be corrected. MAN did not begin production in the fall or winter of 1941. Production of the PzIII was also hampering MAN, and demand for them was at its peak. This played right into the hands of the Czech companies, which caught up to their competitors.
Differences from the old model
The BMM project was first called TNH n.A. (neuer Art, new type), and was not designed from scratch. The design team used their experience in designing the TNH (better known as LT vz 38 or Pz38(t)) extensively. The overall layout and a significant part of the hull migrated to the new design. The engine was in the rear, transmission and drive wheels at the front. At the same time, the tank was anything but a cosmetically altered Pz38(t).
The design bureau didn't waste their two years of development, and the requirements called for serious changes. The 220 hp Praha NR1 V-shaped 8 cylinder engine was chosen for the TNH n.A. The new engine was longer than the old Praha TNHPS/II (a licensed copy of the Swedish Scania-Vabis typ 1664), so the engine compartment had to be enlarged. The suspension looked similar, but looks can be deceiving. The tank was almost a ton heavier, so it too had to be changed. The diameter of the road wheels grew from 775 to 810 mm, and the tracks were widened from 293 to 305 mm. The drive wheel changed too.
Significant changes were made to the hull. Aside from lengthening it, the front was redesigned. The hull machinegun was removed, replaced with a vision block for the radio operator, similar to the one on the PzIII. The driver received the same vision block. The tank's armament consisted of a 37 mm Skoda A-19 gun and a coaxial MG-34. The tank had no commander's cupola, but had a large bump with observation devices on the perimeter.
Special features
It's worth mentioning the technology for the hull and turret of the TNH n.A. Almost all Skoda and BMM vehicles had riveted hulls and turrets. This design has many drawbacks, including secondary fragments caused by rivets flying off when the tank was hit. The TNH n.A. was the first tank at BMM that was fully welded. According to sources, the first tank was riveted and made from mild steel, the second was welded from mild steel, the third was riveted from hardened steel, and the remaining two were welded from hardened steel. According to the plan, BMM produced one prototype per month. The last tank was produced in April of 1942. It's worth noting that no prototype was entirely welded, as the rear and engine compartment doors were still riveted.
The prototypes differed in other ways. The first one had track covers from the Pz38(t). The tank did not receive observation devices, and they were replaced by screens with snow wipers. The tank was equipped with two Notek lights and an automotive horn on the right side of the front plate. The second prototype, with a welded hull and turret, got new track covers. The third prototype was closer to the first one, but received new track covers and a floodlight on the roof. Later, a Tatra Typ 103 220 hp diesel engine was installed on this tank. Like the first prototype, the third received no observation devices. The tank finally reached its final shape with the fourth and fifth prototypes, which received a full set of optics.
Trials and unfair competition
The first vehicle went through a majority of the trials. In late January of 1942, it was shipped to Kummersdorf where it underwent trials alongside the PzII n.A. and the Skoda T-15. Over a few months, the prototype travelled 3866 km without significant breakdowns, which compared favourably to its competitors. It would appear that the Czech tank was winning, but everything was decided during the second stage of the trials in May-June of 1942. The Pz38(t) n.A. and T-15 lost points for having lower clearance and higher fuel consumption. Additionally, the 37 mm gun ate up precious turret room, whereas the PzII n.A. had a more compact 20 mm gun.
The notes in the report suggest that MAN used their administrative powers, especially regarding armament. The author had to know that the 20 mm gun was already unsatisfactory for the German military in March of 1942. In spring of 1942, requirements were made that the PzII n.A. (Pz.Spw.Wg. II Ausf. MAN) had to have a two man turret with a 50 mm gun. This requirement refers to the turret from the VK 16.02, otherwise known as the Gefechts Aufklärer Leopard. Specifications for the Pz.Spw.Wg. II Ausf. BMM were right next to the Pz.Spw.Wg. II Ausf. MAN specifications, and also feature a 50 mm gun in a Daimler-Benz turret. Overlaying the turret over the BMM design shows that this conversion would have been possible. Either way, nothing more than letters and sketches was done on this subject.
The PzII Luchs achieved a Pyrrhic victory. MAN was so full of orders that only 100 of these tanks were produced. If BMM received an order for its Pz38(t) n.A., the situation might have been different. Nevertheless, the experience of designing the tank was not wasted, and the modernized suspension was used for the Jagdpanzer 38(t) tank destroyer.
The prototypes had various fates. The third prototype served as an experimental testbed for the Tatra Typ 103 engine and solutions planned for the TNH-57-900 tank. The final fate of the other tanks is unknown, but at least one tank survived the war. Judging by the track covers, it's the second or third prototype, but the picture quality is so poor that one cannot tell if the tank is riveted or welded.
Original article by Yuri Pasholok.
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