Friday 31 May 2013

Accuracy Revisited

A while ago, I wrote an article comparing the accuracy of a few guns: the D-25, 88L/56, 88L/71, and ML-20. That article lacked a few details, which I will explain here.

The article talked about how the Germans calculated gun accuracy: using a percentage figure for how often you can expect to hit a 2 meter by 2.5 meter target at a certain distance. Such a measurement is useful for when you are fighting a tank that is 2 meters tall and 2.5 meters wide, and not really in any other case.

The Soviet measurement of accuracy is deviation. You will see many deviations in test documents, but the most important figure, the one that actually makes it into artillery tables and textbooks, is the expected deviation. The average deviation comes in 3 components: vertical, horizontal, and distance. For direct fire, vertical and horizontal are important, for indirect fire, distance and horizontal.

Expected deviation is similar to the 50% radius, except in only one direction. 50% of the shells will land on the closer side of the expected deviation figure, 50% of the shells will land on the further side. Using the two expected deviation figures, you can create an oval inside of which 50% of your shells will go.

Let's revisit the guns in the previous accuracy article. The D-25 has a 50% radius of 24 cm. However, you can see that the distribution of shots in that radius is not circular, it is an oval. I don't have the exact data for the D-25's average deviations, but you can clearly see that the result would be an oval that is a little shorter than it is wide. It is pretty trivial to deduce that the value of the deviations should be approximately 24 cm.

A non-circular result is very common. The ML-20 in that same article has a 50% radius of 32 cm at 1000 meters. However, the average deviations are different from that: 22 cm for vertical and 33 cm for horizontal.

Now, on to some new guns! Artillery tables contain expected deviations for lots of distances and propellant charges, but I will obviously not list all of them. The deviations will be given for 1000 meters, at a full charge, with as many shells as I have tables for. Deviations are taken from the appropriate Soviet artillery table. I have the full ones, so if you need them, ask. For each gun, I will also give the distance at which it can hit a German target 50% of the time with the regular AP shell, to compare it with the German accuracy metric.

Let's start with a classic, the 76 mm F-34 gun, mounted on the T-34-76 models 1941 and 1942:
  • HE shell OF-350, O-350A, and D-350 smoke grenade:
    • Vertical: 30 cm
    • Horizontal: 30 cm
    • Trend: horizontal deviation grows much slower than vertical deviation.
  • AP shell Br-350A and Br-350B
    • Vertical: 30 cm
    • Horizontal: 30 cm
    • Trend: horizontal deviation grows a little slower than vertical deviation.
  • HEAT shell UBP-353A
    • Vertical: 50 cm
    • Horizontal: 50 cm
    • Trend: deviations grow at the same rate.
Looking at a very extreme range, the F-34 has an average deviation of only 1 meter at 3 km. That means that the German 2x2.5 meter target would still be hit more than half the time. Jentz writes that the Tiger could hit the target 53% of the time at that range. Pretty comparable.

The 122 mm model 1938 howitzer (M-30) has the following deviations:
  • HE shells OF-462 and O-462A, smoke shell D-462
    • Vertical: 50 cm
    • Horizontal: 60 cm
    • Trend: vertical deviation grows a little faster than horizontal deviation.
The range at which the gun can hit the above German target 50% of the time is 2000 meters. 

The 45 mm model 1942 gun isn't quite that accurate (model 1932 and 1937 results are identical):
  • AP shell Br-240 and shrapnel O-240 and O-240A
    • Vertical: 50 cm
    • Horizontal: 60 cm
    • Trend: horizontal deviation grows faster than vertical.
  • APCR shell Br-240P
    • Vertical: 50 cm
    • Horizontal: 50 cm
    • Trend: horizontal and vertical deviations grow at the same rate.
The deviation gets to around 1 meter in each direction at 2000 meters, not that there is much a 45 mm gun can penetrate at that range. 

Here is a gun we haven't seen before: the T-60's ShVAK 20 mm autocannon:
  • AP incendiary and fragmentation-incendiary shells:
    • Vertical: 70 cm
    • Horizontal: 70 cm
    • Trend: vertical deviation grows faster than horizontal deviation.
The distance at which a German target has a 50% hit ratio is 1500 meters.

The 12.7 mm DShK was in a T-40 tank, that's tank gun enough for me!
  • B-32 AP bullet
    • Vertical: 76 cm
    • Horizontal: 59 cm
    • Trend: vertical grows faster than horizontal.
  • BZT-44 AP-incendiary bullet
    • Vertical: 98 cm
    • Horizontal: 67 cm
    • Trend: vertical grows faster than horizontal.
The 50% distance is also 1500 meters.

That's all I have for now on the Soviets, so now let's take a look at some foreign guns. The first up is the British 40 mm 2-pounder.
  • AP shell and AP shot
    • Vertical: 40 cm
    • Horizontal: 20 cm
    • Trend: horizontal deviation grows much faster than vertical deviation, despite starting out smaller.
This gun hits the German target 50% of the time at a distance of about 2250 meters.

Now, some American guns. First, the 75 mm M2, from the M3 Lee.
  • AP shells M61 and M72
    • Vertical: 30 cm
    • Horizontal: 30 cm
    • Trend: vertical deviation grows much faster than horizontal deviation.
  • HE shells M48 and MK1
    • Vertical: 40 cm
    • Horizontal: 30 cm
    • Trend: vertical deviation grows much faster than horizontal deviation.
The range at which this gun hits a German target 50% of the time is about 2250 meters.

The other gun on the M3 Lee, the 37 mm M5:
  • AP shell M51
    • Vertical: 40 cm
    • Horizontal: 40 cm
    • Trend: vertical and horizontal deviations grow at the same rate.
The range at which this gun hits a German target 50% of the time is a bit less than 2000 meters.

Next, the German guns. The 3.7 cm PaK gives the following results:
  • AP Pzgr
    • Vertical: 50 cm
    • Horizontal: 50 cm
    • Trend: vertical and horizontal deviations grow at the same rate.
  • HE Spgr
    • Vertical: 50 cm
    • Horizontal: 30 cm
    • Trend: vertical grows much faster than horizontal.
The gun loses enough penetration to not be of any use before it can fail to hit a 2*2.5 meter target 50% of the time, (the table only goes up to 1500 meters). 

The German heavy 105 mm model 1918 gun has the following deviations:
  • HE 19 KPS and FES (deviation given in meters)
    • Vertical: less than a meter
    • Horizontal: less than a meter
    • Trend: vertical deviation grows faster than horizontal deviation.
  • AP Pzgr. rot.
    • Vertical: 40 cm
    • Horizontal: 20 cm
    • Trend: vertical deviation grows much faster than horizontal deviation.
Due to the rapidly growing vertical deviation, it is not possible to accurately gauge the 50% distance. It would be somewhere just over 2000 meters.

In conclusion: the average deviation for most guns is more or less in the same range, 30-50 cm at 1000 meters. Even with the largest deviation (98 cm on the the worst machine gun bullet), a gun is going to hit any remotely tank-sized object more than half the time. Penetration is the issue here, as a lot of these guns can shoot much further than they can usefully penetrate anything.

The myth of superior German accuracy is, once again, proven false. The average deviation of the D-25 is comparable to the 88L/71, and the long-range accuracy of the F-34 is the same as the 88L/56.

Update: I found the complete artillery table for the 88L/71 KwK 43 gun. It is posted here

Wednesday 29 May 2013

Unconventional Anti-Tank Warfare

Sometimes, you have to make do with what you have, even when fighting tanks. And sometimes, all you have are ordinary tools. In that case, what you do might show up in a newspaper, and then, with the help of artists from "Combat Pencil", a magazine.

"1. Soldier Kulishev was out scouting one night. An enemy tank crawled out of the forest. He threw a bundle of grenades, and the tank stopped.

2. The tank opened fire, but no one answered. Kulishev took off his boots and silently climbed up on the tank.

3. The hatch opened, and a fascist tanker peeked out. Kulishev hit him in the head with his shovel. The fascist fell back, and the hatch closed.

4. Not wasting time, Kulishev blocked the machine guns with branches, covered observation ports with clay, and blocked the air intakes.

5. The fascists started choking and climbing out of the tank. Kulishev knocked out a second one with his shovel. The third one surrendered. This is how, with bravery, initiative, and quick wits, soldier Kulishev defeated a tank one on one. 

Izvestiya, from July 17th, 1941"

The illustration shows a PzI, but, seeing as how he took out three crewmen, it was most likely a PzII. 

Here is another issue of the magazine. The tank-related story is the one on the bottom.

"Three German tanks entered Pinsk. The fascists miscalculated, and ran out of gas. Pinsk partisans surrounded the Germans. Some swift and strong blows with a mallet, and the barrels of their machine guns were useless. However, the fascists were protected by armour. How do you get them out? Pinsk blacksmiths and workers brought mallets and hammers, and started hammering at the armour. The German fascists, unable to withstand the noise, surrendered.

Pravda, July 12th"

Monday 27 May 2013

F-34 vs German Tanks

Many sources point to the gun of the T-34 as a weakness, as it was incapable of harming a Tiger at over 500 meters. While this is true, it is misleading. While the T-34's 76.2 mm F-34 AP shell was, indeed, not very good against a Tiger, it was much more than enough against the overwhelming majority of German tanks. This article contains the results of testing its AP and HE shells. The "Report on the shooting of German tanks with AP and HE shells from tank guns" (CAMD RF 38-11355-832) contains the data we need.

First up, as always, is the Pz 38(t). The first shot is fired from 800 meters, with a devastating effect. The 76 mm shell penetrates the turret platform from the front, tears off the front plate, and shatters it into pieces. The fragments then enter the crew compartment.

The testers switch to an HE shell. They fire at the front of the tank hull from 800 meters. The front plate is bent by 40 mm. The welding seam holding it front plate burst (300 mm in length). The two front wheel carriers are torn off (each is held on by 4 bolts). 12 bolts popped off the front armour plate.

The next shell is aimed at the front of the turret from the same distance. The front armour plate is torn off in an area right of the gun. Fragments of the front plate enter the turret. The next shot is aimed at what's left of the turret platform from 900 meters. The remainder of the front plate is shattered by the HE shell, and the pieces fall inside the tank.

Another shot from 800 meters, this time at the side. A 200 mm breach is formed in the outer armour plate, 300 mm breach in the inner one. A shot from 950 meters makes a breach 100 mm in diameter, and results in 90 mm long cracks running through the side armour.

The next target is the side of the turret, from 950 meters. The turret is torn off, and displaced 150 mm. The turret ring is destroyed. The right side of the turret is destroyed.

The next target for the F-34 is the PzIII. The loader switches back to AP. The gunner fires from 900 meters. The front armour is penetrated (entrance diameter 120 mm, exit diameter 165 mm). The tank's gearbox is destroyed. Notice the large diameter of the breach compared to the shell's caliber. This is a sign of over-hardened or poor quality armour.

The next target, again from 900 meters, is the sloped portion of the front armour. The armour plate is fragmented in an area up to one meter away from the breach. The welding seam holding the plate bursts over a length of 1.5 meters. The armour fragments enter the crew compartment.

Another shot from 900 meters, this time from the side. A torsion bar limiter is torn off. A hatch is torn off. The tire of one of the wheels is torn off.

The testers switch back to HE. The first shot from 900 meters shatters the left side of the turret platform over a span of one meter. Another shot makes a breach in the lower hull 240 mm in diameter, as well as a breach 300 mm in diameter in the bottom of the PzIII. An idler is knocked off. The gas tank is punctured.

Another shot makes a 400 mm breach in the side of the tank, knocks out the rear wheel shock absorber, and damages the engine and radiator with the fragments. Another shot at the right side of the turret tears off the turret hatch, destroys the turret ring, and bends the side armour by 60 mm. Fragments of the armour "damage everything inside the turret". The last shot bends the side armour by 50 mm, tears off the right side of the turret platform, and shatters it into three pieces.

Conclusions: "The 76 mm AP shell penetrates the 60 mm of front armour at 900 meters. We did not test larger distances. The 76 mm HE shell destroys the side armour and turret from 900 meters."

The PzIV is tested next. Its front armour is penetrated at 500 meters (entrance diameter 90 mm, exit diameter 100 mm). From 800 meters, another penetration. The front armour plate is shattered into two pieces. Another shot from 800 meters penetrates the front. The testers switch to firing at the side at 800 meters.

The side is penetrated. The 20 mm armour screen is torn off the bolts that hold it. The shell keeps going, and penetrates the other side of the hull, and its armour screen. Total penetration is 80 mm. Another shell penetrates the side, but only one side this time. It knocks off the wheel carrier.

The gunner aims at the turret. The hatch of the turret is torn off with a direct hit. The side of the turret bends inwards 50 mm. Another shot impacts the commander's cupola, tearing it off, and throwing it 5 meters. The hatches on top of the cupola are also torn off, and thrown 30 meters. Another shot to the side of the hull forms a 130 by 350 mm breach.

Conclusions: "The 76 mm AP shell can penetrate the front of a PzIV at 900 meters. We did not test larger distances. The 76 mm HE shell destroys the side of the turret and hull at any range."

From conclusions of the document:
"The 76 mm long-range HE-fragmentation steel grenade fired from a 76 mm gun (F-34) model 1940 installed in a T-34 tank, on impact with the Czechoslovakian 38t tank, side or rear 30-20 mm German tanks PzIII, StuG, and PzIV, destroys armour plates from 1000 meters, damaging the tank and crew with the fragments.
The 76 mm AP shell, when fired from a 76 mm gun (F-34) model 1940, penetrates the front armour of German tanks PzIII, PzIV, and Pz 38(t) from 800-1000 meters. The penetration ability from over 1000 meters was not checked.
The 76 mm model 1940 (F-34) gun is an effective weapon against all German tanks, based on its AP penetration and HE shell destructive properties."

According to calculations of NII-48 in topic 2VV-2 "Investigation of the armour of tanks of the German army" (CAMD RF 38-11355-778), the following are the distances at which an F-34 can defeat the armour of a Pz 38(t):

  • 90 degrees
    • Turret and hull front: 1970 meters
    • Turret platform front: 1970 meters
  • 80 degrees
    • Turret and hull front: 1970 meters
    • Turret platform front: 1940 meters
  • 70 degrees
    • Turret and hull front: 1900 meters
    • Turret platform front: 1860 meters
  • 60 degrees
    • Turret and hull front: 1690 meters
    • Turret platform front: 1600 meters
  • 50 degrees
    • Turret and hull front: 1320 meters
    • Turret platform front: 1250 meters
  • 40 degrees
    • Turret and hull front: 880 meters
    • Turret platform front: 840 meters
  • 30 degrees
    • Turret and hull front: 490 meters
    • Turret platform front: 420 meters
Tactical diagram for a Pz38(t). The F-34 is shown as the double dotted line (front only)

For the PzIII, a much larger number of armour groups was tested, to the point where it would be massively inconvenient to transcribe the full chart (if you absolutely must have it, let me know), but here it is for a slightly angled tank, at 80 degrees:
  • Upper front plate: 800 meters
  • Lower front plate: 1800 meters
  • Turret platform front: 1970 meters
  • Turret front: 1970 meters
  • Upper rear: 1940 meters
  • Middle rear: 1900 meters
  • "All other parts of the tank can be penetrated with a 76 mm AP shell at any distance, at any angle". 
The conclusions made are as follows: "The protection from 76 mm AP shells is unacceptable. Even its front is penetrable at 900-1200 meters when standing at 45 degrees, and exposing many more vulnerable parts."

Tactical diagram for a PzIII tank. The F-34 is shown as a dotted line for the front and back.

For a PzIV, similar conclusions (again, at 80 degrees):
  • Side with armour screen: 2000 meters
  • Turret and hull front: 1970 meters
  • Turret platform front: 1970 meters
  • "All other parts of the tank can be penetrated with a 76 mm AP shell at any distance, at any angle".
The conclusions made are as follows: "The protection from 76 mm AP shells is unacceptable. Even its front is penetrable at 1100 meters when standing at 45 degrees, and exposing many more vulnerable parts."

Tactical diagram for the PzIV tank. The F-34 is shown as a dotted line for the front and sides.

The same table is made for a StuG III, but only the front armour plate. The result is the same as a PzIII: vulnerable at 1970 meters, 1100 meters at a 45 degree angle.

CAMD RF 38-11355-776, a NII-48 article on domestic armour quality, also discusses experimental HEAT shells. These shells were capable of penetrating 30 mm of medium hardened armour and 45 mm of highly hardened armour at a distance of 1600 meters, at every tested angle (maximum tested was 45 degrees).

Sunday 26 May 2013

Red Rambo

Sometimes people have creative ideas about things, and sometimes those ideas end up in archives.

"We propose, that the 20 mm caliber would be used much more widely, if the question of its use, and the construction of the weapon that fires it, was approached from a different angle. The mass of the system should be reduced, barrel pressure lowered, recoil reduced, and the gun turned into an infantry weapon: a hand cannon. Of course, the gunpowder charge would be drastically reduced, which will result in loss of muzzle velocity and penetration effect."

The 20 mm autocannon was used in the T-60 tank, as well as on Soviet aircraft. It would take quite a Rambo character to carry one. Although, maybe it was meant for this guy:

"On July 13th, 1941, Red Armyman Ovcharenko was transporting ammunition for the 3rd company in the Pesets region, and was 4-5 kilometers from his unit. In that region, two armoured cars, 50 German soldiers, and 3 officers surrounded him.

A German officer exited the car, and ordered Ovcharenko to raise his hands, took his rifle, and started questioning him. Ovcharenko had an ax in his cart. He grabbed the ax, chopped off the officer's head, and threw three grenades at a nearby car. 21 German soldiers were killed, the rest ran in panic. Ovcharenko pursued a wounded officer through a garden in the Pesets village, caught him, and also chopped his head off. The third officer ran away.

Comrade Ovcharenko calmly collected the documents of the dead, the officers' maps, papers, diagrams, notes, and delivered them to the regimental headquarters. The ammunition was delivered to his company on time. Comrade Ovcharenko continues his combat service, promoted to a machine gunner."

Edit: I have found the full text of the award order!

Ovcharenko was recommended for the Hero of the Soviet Union medal, combined with the Order of Lenin.

Friday 24 May 2013

Penetration, Part 3

I posted penetration tables before (part 1, part 2), but I am not even close to collecting the data for every gun. Here are some more guns, some we have seen before, and some we have not.

CAMD RF 81-12104-9

The first gun is a 45 mm model 1937. It can penetrate 30 mm at a 30 degree slope at 1000 meters, but 40 mm at the same slope at only 150 meters. This performance is better than in part 1 (a different model 45 mm gun is used) and worse than in part 2 (no indication of what model tank gun is used).

Next are the L-11 and F-32 76 mm guns. They can penetrate 40 mm sloped at 30 degrees from 900 meters, but 50 mm sloped at 30 degrees at only 300 meters. This is more or less consistent with the findings in part 2.

Next, we see some unfamiliar faces. The 76 mm model 1902/30, model 1938 (also referred to as a model 1939 in a different part of the document, making it unclear what gun this is), and F-34 guns. They are capable of penetrating 50 mm of sloped armour at 800 meters (quite an improvement over the shorter 76.2 mm guns), or 60 mm at 400 meters.

Here's something brand new. The 76 mm AA gun model 1931 (which was trialed inside a T-34 under the index S-54 in 1943) can penetrate 70 mm of armour sloped at 30 degrees at a distance of 1000 meters.

The 107 mm M-60 gun can penetrate 100 mm of armour at a 30 degree angle at 900 meters (although here it can penetrate that armour at 1000 meters).

The 122 mm model 1938 howitzer (M-30) penetrates 30 mm of sloped armour at 1000 meters. The HE shell breaches the armour, the shell explodes, and strikes the insides of the tank with shell and armour fragments.

The 152 mm model 1938 howitzer (M-10) is tested with three shells. The first is a naval HE (half-AP) shell. It can penetrate 100 mm of "reduced quality" flat armour at 500 meters, or 90 mm of the same armour at 30 degrees. A newly developed AP shell doesn't work so well: at 50 meters, it can only dent an angled 90 mm plate, but is capable of breaching it if it is flat. The resulting penetration is less than a caliber. The old concrete piercing shell can penetrate a 70 mm plate at 500 meters, but only if it is flat. The same plate at 30 degrees cannot be penetrated.

The 122 mm model 1931 gun (A-19) penetrates 100 mm of armour at 30 degrees from 900 meters with a concrete piercing shell.

The 152 mm model 1937 gun-howitzer (ML-20) is also tested with several shells. The naval HE (half-AP) shell penetrates 120 mm of armour at 1800 meters, and 100 mm of armour at 30 degrees from 2000 meters.  A new concrete piercing shell penetrates 100 mm of armour at 230 meters. The old AP shell cannot penetrate 90 mm of armour at 500 meters, but could penetrate 80 mm of armour at 30 degrees at 2600 meters (that's not a typo, really, 2600). The shell breaks up and penetrates the plate in pieces.

Now, we get to the big guns. The 152 mm model 1935 Br-2 gun, with a naval HE (half-AP) shell, can penetrate 180 mm cemented armour at 1900 meters, and 152 mm if the plate is angled.

The 203 mm model 1931 howitzer (B-4) can penetrate 102 mm of armour with its light concrete piercing shell (100 kg) at 500 meters, and 27 degrees. The heavy concrete piercing shell (146 kg) can penetrate that same plate at the same angle at 1800 meters. In either case, the shells break up, and penetrate the plate in pieces.

The 280 mm Br-5 mortar, with its 240 kg concrete piercing shell, can only dent 102 mm and 90 mm armour plates at 1700-1800 meters. The rounds shatter into pieces.

Wednesday 22 May 2013

World of Tanks History Section: KV-1

In the middle of the 30s, anti-tank guns became popular in armies of the world. This was due to several reasons. One was that 3 inch divisional guns were ineffective against with a mobile target like a tank. Another was that anti-tank rifles were not that effective against armour either. After penetrating armour, the bullet had very little kinetic energy left, and was frequently unable to damage the internals of the tank. However, light and rapid firing weapons of 20, 37, or 47 mm could easily transform any tanks of the era into scrap. Experience in the Spanish Civil War highlighted this.

After analyzing this experience, the Commissariate of Defense ordered the creation of a heavy tank, with armour thickness of at least 60 mm, in 1938. At that point, the thickest armour the only heavy Soviet tank had was 30 mm.

At that point, military minds were certain that a heavy tank needs at least two guns: one to combat infantry, and one to combat tanks. This is why the new tank was initially planned to have several turrets. First 5, like the T-35, then three. Finally, engineers decided on two turrets. Two heavy tanks started development. Both were developed at the Kirov factory in Leningrad. S. A. Ginsburg's construction bureau was developing the T-100, and J. Y. Kotin's SKB-2 was developing the SMK (Sergei Mironovich Kirov).

At the time, the multi-turret construction became heavily criticized. Vehicles of this type were complicated and unreliable. The tank commander had difficulty commanding two guns at once. The gunners effectively had to pick their own targets. This was hardly a rational setup.

Along with the multi-turreted SMK and T-100, it was decided to make another, single turreted tank. The project was sent to the SKB-2, along with several fifth year interns from the Military Academy of Mechanization and Motorization. Under the guidance of engineers L. E. Sychev and A. S. Ermolayev, they developed a single turreted tank named KV (Kliment Voroshilov). The final stages of the project were completed under N. L. Duhov.

The KV was based on the SMK tank. The suspension was shortened by one wheel, and both guns (45mm and 76mm) were placed in the same turret. The crew was decreased to 5. Removal of the second turret lightened the tank significantly, allowing the front armour to grow to 75mm. The tank was powered by a 500hp V-2K engine.

In December of 1938, at the meeting of the projects commission that was evaluating the SMK project, Kotin and the factory director, I. M. Zaltsman, proposed the to build a KV as well as a prototype of their multi-turreted creation. In February of 1939, the permission was given.

The project was polished and the prototype was built by August. On September 1st, the KV took its first trip to the factory testing grounds. After defects were discovered and corrected, the tank was shipped to Moscow for a demonstration to the government and further testing at Kubinka. Further evaluations showed that that KV matched the SMK in speed, and surpasses it in cross country performance. Crew was also down to 5, from the SMK's 7. The tank was physically smaller, allowing it to use terrain to its advantage. On the other hand, several defects were found in the transmission, and the V-2 engine was new enough to be far from perfect.

The tank was sent back to work out the defects, but the Winter War started, and the Red Army tripped up at the concrete fortifications of the Mannerheim Line. The Soviet Union had no breakthrough tanks short of the T-28, whose 30 mm of armour was vulnerable to Finnish AT guns. Experimental KVs and SMKs were sent to Finland to undergo trial by fire.

Before going into battle, the KV was modified. The 45mm gun was swapped out for a DT machine gun. The KV's first battle was on December 18th, during which the tank demonstrated the advantages of its thick armour. 10 hits were received from 37 mm guns, zero penetrations. However, one hit the gun, which had to be replaced.

The SMK's performance was much less exemplary. Technically, one cannot fault the crew or the engineers; the tank was immobilized by a hidden mine. Regardless, the KV took the spotlight, and was adopted by the Peoples' Commissariate of Defense on December 19th. The Kirov factory was ordered to solve existing defects and begin mass producing the KV starting January 1st, 1940.

The KV's 76 mm gun was found to be insufficient for penetrating concrete bunkers. An order was issued to investigate the possibility of installing a 152 mm howitzer on the KV. This was achieved, and resulted in the KV-2 modification, which will receive its own article. The KV with a 76 mm gun was retroactively renamed KV-1.

In 1940, the Kirov factory was to release 50 KV-1 tanks. Even after getting rid of newly found defects, this order was very realistic. However, the order was increased to 230 tanks, which was problematic. The factory director tried to explain his position, but the pressure from the top was too great, and he found no other way than to report that the factory was meeting the needs of the Motherland. This deception was uncovered, but the volume of work was deemed too great after all, and Zaltsman only received a warning.

Work on the KV-1 continued; improving the transmission, air filters, turret rotation mechanism, and low reliability of tracks and road wheels took all of 1940. Only in July, 350 changes were added to the blueprints.

Two factories were to build KV-1s: Kirov factory in Leningrad and the Chelyabinsk Tractor Factory. After WWII started, the production of KV tanks clustered in the Urals, especially after the Kirov factory was evacuated to Chelyabinsk.

At the start of WWII, the Red Army had 630 KV tanks of both modifications. Despite all efforts, their reliability was still lacking, and factories were constantly failing to produce enough spare parts to keep all divisions equipped. A large portion of KV tanks was constantly incapable of combat, as they were undergoing repairs.

All things considered, the KV (and T-34) tanks became a harsh surprise for the Germans. They were nicknamed "Ghost" due to their perceived invincibility. Even though the KV was a formidable opponent, the Germans figured out how to combat it effectively.

The KV was a powerful tank, but it was also a problem-prone one. By the start of the war, it did not attain the required levels of reliability. Furthermore, the lighter T-34 was seen as more satisfactory to military commanders. The KV was created as a temporary tank, always destined to be replaced a few years later by a more perfect tank, but it remained in production due to the war. When the Germans started rolling out Tiger and Panther tanks, the KV was deemed ineffective. In 1943, the KV-85 was developed that could combat new German tanks, but it was not widely deployed, since the newer and more capable IS was already being built.

Original article available here.

Monday 20 May 2013

Re-arming German Tanks

The image of disciplined German soldiers methodically destroying their tanks so that the enemy does not get them is spread through popular history, but, in reality, was not true. The Red Army captured plenty of fully functional tanks, some in the first battle they ever participated in. They captured so many, that the issue of re-arming them came up. Re-arming German tanks with domestic guns would solve the problem with ammunition supply, if not the problems of parts and high-octane gasoline.

The question was first raised in 1942.

CAMD RF 81-12038-23

"According to the information supplied to you by deputy chief of the 2nd department of the Artillery Committee of GAU RA, engineer 2nd class comrade Getman on the necessity of re-arming captured tanks and SPG, and the discussion with engineers Sinilshikov and Pererushev, we decided that the following installations were possible:
  1. 76 mm F-34 tank gun on the PzIV tank.
  2. 45 mm tank gun on the PzIII tank.
  3. 45 mm tank gun or 20 mm ShVAK autocannon on the Pz38(t) tank.
  4. 122 mm howitzer M-30 on the StuG SPG.
Currently, Sinilshikov is only dealing with re-arming the StuG. His team already started developing a project. I am sending you a copy of the M-30 schematic, and if you do not object, please pass it on to comrade Sinilshikov. I am also sending you sketches of other turrets with German guns installed, to be used as you deem necessary. Keep me informed on your progress."

The M-30 project is the only one of these that went anywhere, creating the SG-122 (Self Propelled Howitzer, 122mm). 21 SG-122s were built out of StuGs and PzIIIs, but by that time the SU-122 was no longer used, and the equivalent SG-122s were sent to tank schools. Additionally, a project to install a 76 mm tank gun on the StuG was launched, creating the SU-76I, in 1943. 201 were built. 

A project to re-arm Tigers and Panthers was also launched. The Panther would receive an 85 mm gun and the Tiger a 100 mm gun. 

Here is a blueprint of a Tiger turret with a D-10T and a TsH-17 sight.

CAMD RF 81-12038-775

By 1945, the obsolete tanks were dropped and estimates on the work necessary were made.

CAMD RF 81-12038-775

A PzIV took 80 man-hours to convert to a ZiS-5 or a F-34. A Panther getting an 85 mm gun took 120 hours. A Tiger getting the D-10T took 90 hours. A fragment of the blueprint shows the true name of this chimera: T-VI-100.

However, by 1945, victory was near and the tank shortages of 1941/42 were long behind. Captured tanks were no longer needed by anyone except museums, and work on re-arming them stopped. 

Sunday 19 May 2013

Tank Plans for 1941

I've written before that the USSR was planning to make the KV-3 tank its primary heavy tank in 1941, and one of the KV-3, 4, or 5 in 1942, but just how many KV-3s were they planning to build? Was it going to be just a few pre-production models, or a full scale manufacture?

Full scale manufacture it is! GABTU's plans for 1941 order the Kirov factory to produce 500 KV-3s, 400 KV-1s, and 100 KV-2s. Those KV-3s are quite expensive, 40% more expensive than a KV-1.

Plans change, of course. In reality, the Kirov factory built 611 KV-1s, 204 KV-2s, and just one KV-3, if you count the T-150 as a KV-3.

Going through unfulfilled orders, another unbuilt tank pops up, the T-34M. The T-34M (factory designation A-43) was a modernized version of the T-34, with features that would be seen in Soviet medium tanks several years after, like torsion bars, a 5 man crew, a commander's cupola, a planetary gear transmission, and internal shock absorption.


The scan is a bit cut off, but the production of T-34s wanes to only 40 units over the month of September, and is fully replaced by T-34Ms by October. It is interesting to point out that 380 out of the 800 T-34Ms were armed with a ZiS-4 gun, instead of the F-34 gun that the overwhelming majority of T-34s received. 300 of the tanks were also to be equipped with a flamethrower, aside from their main guns (65 F-34 armed T-34Ms and 235 T-34Ms with a ZiS-4). That was one way of compensating for the deficiencies of the 57 mm HE shell.

We also see that, unlike the KV-3, the T-34M is not that much more expensive than the tank it is replacing. As for the prices themselves, they shouldn't be relied on in any kind of analysis. The document itself notes that these prices are just approximate (since production has not started yet). Additionally, this is way before most simplification and cost-cutting measures were taken. According to Ural Train Factory (UVZ) data, a T-34 cost 246 900 rubles in 1941, and 142 100 rubles in 1944. 

Friday 17 May 2013

Penetration, Part 2

I have already written an article on a very wide-spread penetration table. Here is a table for some lesser-known guns (regrettably, missing most of the ones I was interested in).

CAMD RF 38-11353-950

This document shows the penetrations of some pre-war guns, and their caliber, muzzle velocity, and shell weight. This table lists some guns we're seen before (ZiS-4, 45 mm tank gun, F-34), but some new ones. There is the DShK, whose practical penetration I covered here. The table gives it 25 mm at 0 degrees and 200 meters, and 10 mm at 30 degrees at the same distance. This seems pretty fair when compared to those tests.

Another interesting gun is the F-30. It was tested in the T-28, and never made it into anything in mass production. 100 mm at 1000 meters at 0 degrees and 90 mm at 30 degrees is around the same as the D-5-T. A lot of the time, different guns that use the same shell do not actually possess different ballistic properties, but are instead differentiated by cost, size, ease of use, etc.

We see another gun I covered next, the ZiS-6. The penetration against a 30 degree sloped plate is the same as in that document, but this document shows the penetration against a flat plate at that distance: 128 mm.

The gun after that is the M-10 on the KV-2. I can't imagine that it was used very frequently with AP, given how devastating its HE shell was. There is at least one case of KV-2s using concrete-piercing shells against tanks. This gun achieves 85 mm against a sloped plate at 1000 meters, and 90 against an unsloped plate. This is worse than the ML-20 152 mm gun in the other penetration table, which is expected, given the M-10's shorter barrel length.

CAMD RF 38-11353-951

Now we get into something really interesting: foreign guns. Since there was not yet a chance to discover the penetration of German guns firsthand, these are based on data from military intelligence. Let's take a look. Keep in mind that a) this data is from gathered intelligence and is bound to be approximate, especially considering that b) the Germans tested to a 50% penetration standard, and the Soviets to a 75% penetration standard.

The first entry is "Rheinmetall Borsig" 37 mm. The shell mass is reported as 0.665 kg, at 800 m/s. This penetrates 40 mm at 250 meters and 26 mm sloped at 30 degrees at 600 meters. The Germans' own data shows the 3.7 cm PaK 36 as having 31 mm sloped at 30 degrees of penetration at 500 meters. Projectile weight and muzzle velocity are pretty close too. 

The next gun is "Rheinmetall Borsig" 47 mm. I have no idea what this is supposed to be, but it doesn't penetrate very well, and this is at very close distances.

Next is an 88 mm AA gun. Apparently it shoots a 9 kg shell at 820 m/s, which is a little too light and a little too fast, but the penetration numbers given seem consistent with that other penetration table data. 

The next gun is a new one, "heavy gun", 105 mm, maybe a 10.5 cm FlaK gun. The one after is an "anti tank (and also AA) gun, exactly matching a 5.0 cm PaK 38.

After that, we see something interesting: a 66 mm light AT gun, penetrating 75 mm of armour at 800 meters, or 75 mm of sloped armour at 200 meters, firing a 4.5 kg shell at 850 meters per second. Perhaps this is data from some kind of 75 mm squeezebore gun. Or maybe a captured Czech gun? 

The last entry in the table is an 88 mm AT gun, which, for some reason  fires a different shell at a different velocity than the 88 mm AA gun, and also penetrates the same amount of armour at 100 meters, angled or not. 

Wednesday 15 May 2013


An interesting episode in a battle for Polunino, next to Rzhev, in August of 1942.

The 119th Tank Brigade writes: "August 18th, 1942. In battle on August 16th, Lieutenant Suharkov's tank, fighting near the enemy positions in Galahovo, grabbed a 37 mm gun, tied it to the tank using his coat, and towed it back to our infantry's positions. Along with the gun, the crew retrieved a case of 37 mm shells."

Kriegstagebuch 1/58: "...enemy tanks freely cross our positions and move among them. Our infantry witnessed as enemy tankers took three MG34 machine guns, one light mortar, and even towed away a 3.7 cm anti-tank gun..."

Tuesday 14 May 2013

German Soldier Quality

The idea that German soldiers were inherently superior to the Allies is common in popular history. However, German General Franz Halder wrote "Our infantry does not even closely compare to what we had in 1914." Captured German documents seem to agree with him.

A document from a dead unteroffizier, dated September 25th, 1941, captured in the region of Kiskino 4 days later, states:

"Order to the 489th infantry regiment, 269th division.

It has been found once again that, during offensives and defenses, infantry and machine gunners would not open fire at the enemy, in fear of being located by enemy artillery located nearby.

I must state that this behaviour is unacceptable, fake, and incompatible with the fighting spirit of a German soldier. This indicates a lack of bravery, cowardice, and poor morale.

A soldier that behaves this way stops being a warrior, feels inadequate, and demonstrates to the enemy that he is already beaten.

We must show the Russians the opposite, that we have absolute moral superiority. We cannot, especially now, at our goal, at the gates of Leningrad, feel weak. Our unit must fight with doubled efforts and self-sacrifice. We owe this to our wounded and dead comrades.

I demand that all soldiers, especially new reserves, must focus all of their will and skill, in order to complete the task we have been given in time.

I order to open fire at any Russian from 600 meters. The Russian must know that they have a focused enemy, from which he can expect no mercy. Only then will the enemy keep a respectful distance, and will not  be in a condition to counterattack.

Artillery and grenadiers are only helpers, in an offensive or defensive operation, the most important and decisive factor is the infantryman, and this can only happen when every soldier shoots as long as possible.

Anyone found to hold their fire due to fear or indifference will be tried by a court-martial. We are in a battle where the question of "to be or not to be" is decided. Each one of you must know this, and express it in your relation to the enemy. Our slogan is the destruction of the enemy by all means, and this means shoot, and shoot more, it cannot be otherwise."

That regiment is not the only one having trouble with new recruits. The 40th Tank Corps had similar problems. CAMD RF 500-12462-135, dated February 18th, 1942, tells it in detail:

"In addition to the above document, the division reports: out of 1092 privates:
  • 25 did not undergo basic training.
  • 87 did not undergo line training, do not know how to throw grenades, did not undergo entrenchment training.
  • 284 are only good for work battalions, and also did not finish basic training.
From the remaining 596 men, the following did not finish training:
  • 82 did not undergo line training.
  • 132 cannot throw grenades.
  • 36 did not finish entrenchment training. 
Out of the 1092 privates, the following illnesses are observed:
  • Heart, lungs, asthma: 71
  • Flat feet: 95
  • Internal illnesses: 58
  • Other illnesses: 4
The quantity of the reinforcements does not satisfy the requirements given by front-line units. The front-line units also cannot train the reinforcements, since they do not have time. We request that the reinforcements be already trained, since training in these conditions is difficult and time consuming.
The poor quality of reinforcements must be seen as the largest and most important danger to units. Even the best regiment must refuse these reinforcements, as the amount of experienced soldiers at a minimum. Here are two examples of their behaviour in battle:
  1. When the first shots were fired, the recruits buried themselves in the snow and were useless for battle. When the officers tried to encourage them, they pretended to be dead. When the Russians brought in tanks, they got up and ran away.
  2. In another battle, recruits, upon hearing the first shots, hid behind cover and started firing their rifles in the air uselessly. 
I have a feeling, a feeling confirmed by many soldiers, that these reinforcements are composed of soldiers unsuitable for reserves. This can happen if the company commanders have insufficient discipline, or if the company has no superiors with disciplinary powers, and discipline is performed through the chief feldwebel alone. In any case, the impression is that the soldiers sent to the front are those that are disliked by their commander, either due to their level of training, interest in service, etc.
These people bring a great danger to the front. The spirit and combat readiness of soldiers is what ensures success in battle. 
For specific forces, let me note the following:
  • Artillery: needs reinforcements, but untrained soldiers are a burden to the units.
  • Self-propelled battalion: poor terrain training, poor technical training.
  • Sapper battalion: frequently receives infantry with no sapper training. Basic infantry training is not enough.
  • AT battalion: good quality, many volunteers, but are entirely untrained in the use of the 5 cm gun.
  • Communication battalion: poorer training compared to old radio and telephone operators."
The Germans were not the only ones with these problems. The Axis Minors had them too. From CAMD RF 38-11353-349:

"Ostrogozhsk direction: enemy forces fight fiercely for Korotyak. We captured order #25 for the 7th infantry division, signed by Major-General Meze, who demands that, by August 18th [1942], all non-Hungarian soldiers be gathered in separate companies, as they have proven themselves unreliable in battle. Leave only rifles for these companies, and remove all automatic weapons."

Those problems did not improve by 1944. CAMD RF 233-2309-162, states: "Since the beginning of the operation, a very large amount (hundreds of thousands) of anti-tank grenades "Faust" (large and small) and "Ofenrohr" was discovered. Their application is negligible, barely 3% of all knocked out tanks fell to them. This is explained by the weak morale of the German infantry, shocked by our rapid advances. They run when our tanks are within 200-300 meters (the range of "Faust" is 40-50 meters)."

Monday 13 May 2013

Soviet Armour Research

When you're fighting a war, it's not only important to know how well your guns work against enemy armour, but also important to know how well the enemy's guns work against yours. As always, NII-48 has us covered, with its report titled "The study of the penetrative function of German captured tank shells on domestic tank armour, and methods of combating them", stored under CAMD RF 38-11355-776.

The report first goes over the various German guns used, and the ammunition types: AP sharp-tipped, AP sharp-tipped capped, APCR, HEAT, and solid AP, without any explosive filler, damaging the enemy tank with only its penetrative force. There is an exhaustive list of guns and ammunition for them, and it, perhaps, will be the topic of another article.

In order to evaluate the effectiveness of captured ammunition: high hardness plates 25 mm, 45 mm, and 60 mm thick were produced, as well as medium hardness plates 30 mm, 50 mm, and 75 mm thick. The precise chemical composition of the armour is present in the report, and will also likely be included in a subsequent article.

"The tests determined the following:
  • APCR shells have a harder time penetrating highly hardened armour than medium hardened armour. Highly hardened armour can be penetrated at a range of angles 10-15 degrees less than medium hardened armour of the same thickness. The 60 mm highly hardened plate resists APCR shells 5-10 degrees better than the 75 mm medium hardened plate.
  • Medium hardness armour resists AP shells better, whether capped or uncapped."
The test data is included in the following table, translated for your convenience. PtP stands for Possible to Penetrate. LtP stands for Likely to Penetrate.

"The damage to the armour plates is described as follows:
  • APCR forms a shallow dent from the casing, and a deeper dent or penetration from the core. When impacting armour of medium hardness, the core does not change direction, and passes through the plate at the same angle it was shot at. In case of armour that is highly hardened, its path changes, as if to ricochet. Upon striking the armour at a large angle, the brittle core shatters.
  • The following damage is caused by AP shells with an explosive filler:
    • Clean penetration equal to a caliber: the shell penetrated and exploded past the armour. The shell normalized during passage through the armour.
    • Penetration with ragged edges, frequently larger than a caliber: the shell detonated or was destroyed during its interaction with armour. This most frequently happens with larger calibers.
    • Dent from a ricocheted shell."
The study found that, against hard armour, 50 mm and 37 mm APCR shells do not work as well as AP shells of the same caliber. Also, to no one's surprise, 37 mm guns do not penetrate as much as 50 mm guns.

Tests of a T-34 hull led to the following conclusions:
  • The upper front plate of the hull cannot be penetrated by 50 mm and 37 mm shells, barring cases where the tank is tilted forward due to terrain.
  • The overtrack hull can be penetrated by 50 mm shells, but not 37 mm shells.
  • The side can be penetrated by both 37 mm and 50 mm shells.
  • The rear can be penetrated by 50 mm shells. 
Tactical diagram of a T-34. The tank is facing to the left. The top part is with 50 mm APCR, the bottom part is 37 mm APCR. Distances are extrapolated, and given for "possible penetration" (20%).

Tests of a KV hull led to the following conclusions:
  • The front can only be penetrated by 50 mm APCR shells.
  • The sides can be penetrated by 37 mm and 50 mm APCR, as well as 50 mm AP (in practice, no 37 mm APCR penetrations were found).

Tactical diagam of a KV. The tank is facing to the left. The top part is 50 mm APCR. The bottom part is 37 mm APCR. Distances are extrapolated, and given for "possible penetration" (20%).

Tests of a T-70 hull led to the conclusion that it is only protected from 37 mm shells from the front, which can only be penetrated by 37 mm APCR.

Tactical diagram of a T-70, against a 37 mm gun. Distances are extrapolated, and given for "possible penetration" (20%). 

The report also discusses methods of reinforcing armour, including research into heterogeneous armour and armour screens. Armour screens are described as being effective against HEAT and APCR ammunition, distancing the armour from the shell impact in the first case, and stripping the fragile core of its protection in the second case. 

Factory #9 conducted tests of such screens. The list of the full combination of screens and plate thicknesses is long and tedious but here are their conclusions:
  • Screens very close to the armour are not as effective as screens further away.
  • A thin plate in front of a thicker plate is superior to a thick plate in front of a thinner plate.
  • High hardness screens are superior to medium hardness screens.
  • 15 mm armour screens offer satisfactory protection from APCR and AP shells and any distance and angle.
  • Against capped AP shells, a 15 mm screen is only effective at distances greater than 150 meters. At distances less than 150 meters, a 20 mm screen is needed. At distances less than 50 meters, a 15 mm screen with a 4 mm secondary screen is needed.
  • Against German 75 mm HEAT shells, a 6-8 mm armour screen is sufficient protection.

T-34 with armour screens. Model.

T-34-85 with armour screens. Model.

The results are quite effective, but due to the low amount of APCR and HEAT shells encountered in the field, efforts to screen T-34s were short-lived. Losses due to HEAT were very small: none at all in most of 1942, less than 2% over the winter between 1942 and 1943, and less than 7% in 1943. In 1944, no tanks were lost to HEAT shells from other tanks. Panzerfausts and Panzerschrecks were responsible for 5% of all tank losses that year. Against such portable HEAT weapons, mesh screens were developed. These screens are frequently seen in footage of Soviet tanks in Berlin. However, these screens were not installed on a very large amount of tanks even then, as German infantry tended to be swept out by machine gun fire from the tank and accompanying Soviet infantry at a range of 150-200 meters, greater than the range of the German AT weapons.

T-34-85 tank with HEAT screens. These screens were installed to protect from infantry weapons, not tank HEAT shells, indicated by the screen covering the top of the turret.

The above photograph shows yet another protective measure. One suggestion made by factory #112 was the hanging of five spare tracks in the front of the hull (four are missing in the photo) and two on the back of the turret. 

Based on the experience in the Winter War, the Red Army decided that the potential enemy may develop large caliber guns capable of penetrating Soviet tanks. An order was given in the spring of 1941 to increase the front armour of already built and future T-34s to 60 mm. Two tanks with additional armour were developed in July of 1941. These modifications were discontinued due to the enemy, now no longer potential, lacking any such guns.

In December of 1941, based on news of the Pz III Ausf J and its newfound capability to penetrate the front of a T-34 with APCR, it was decided that T-34s should once again be produced with 60 mm of front armour. Due to the low amount of APCR used by the Germans, this modification was discontinued. Three factories produced a number of these up-armoured T-34s in the winter and spring of 1942.

T-34 with 15 mm of additional armour welded on top of its 45 mm upper front plate, produced by factory #112.

STZ built about 200 tanks with improved armour. Factory #112 built 80 hulls and 109 turrets with additional armour. Factory #112 also cast 8 turrets with the sides thickened to 75 mm. Factory #183 also produced a number of these tanks, but I don't have any data on how many.

Sunday 12 May 2013

Guardsmen in the Fall, Part 7: Battle at Belgorod

"7. Battle at Belgorod

On October 20th, the main forces of the brigade were at Tamarovka and Volhovets. The brigade received an order to fortify in the region of Tamarovka and not to let the enemy reach Belgorod. The brigade had two platoons of T-34s and one platoon of T-40s at its disposal. As of the morning of October 21st, the brigade occupied:
  • Tamarovka, with two platoons of tanks and a company of motorized infantry
  • Height 221.8, a battalion of motorized infantry, missing one company
The terrain was flat, without forests, but very bumpy. The roads were muddy, and difficult for wheeled transport. The weather was cloudy.

A column was spotted on the road from Borisovka to Belgorod, through Blizhniy. The column was attacked with tanks, AT guns, and infantry, as a result of which the enemy lost:
  • Tanks: 2
  • Vehicles: 16
  • Infantry: a platoon
At 17:00, the enemy attacked height 221.8, and took it. We brought in reinforcements, and counterattacked. After a long and bitter battle, the brigade fortified 500 meters east of height 221.8. The enemy lost:
  • Tanks: 5
  • Guns: 4
  • Aircraft: 1
  • Infantry: a company
Our losses:
  • 5 T-34s, all towed successfully
  • Killed: 32
  • Wounded: 44
An infantry division approached from Tamarovka and Streletskoye, and began an attack on Volhovets. 3 KV tanks, coming to reinforce the brigade at height 221.8, met the advance guard and began combat. The advance guard was destroyed, and the rest scattered.

The enemy, supported by AT gun, machine gun, and mortar fire, assaulted the infantry and tanks at height 221.8. A small group of tanks and AT guns held out until nightfall. After nightfall, elements of the brigade were moved to the eastern shore of the river Donets. The enemy, over three days of battle, lost:
  • Tanks: 14
  • Guns: 6
  • Mortars: 2
  • Tractors: 1
  • Vehicles: 15
  • Infantry: a battalion"

Saturday 11 May 2013

Guardsmen in the Fall, Part 6: Battle at Bogoduhov

"6. Battle at Bogoduhov

After the battle at Shtepovka, the brigade did not fight for ten days. As of 10:00 on October 13th, Major-General Belov's forces were as follows:
  • 5th CD: Matveevka
  • 9th CD: Alekseevka, Zaryavinka
  • 6th Guarts ITB: Sennoye
The enemy, with a force of around two battalions, occupied Bogoduhov, and up to a battalion of infantry occupied Gubarevka.

At 15:00, on October 13th, tanks attacked hardpoints at Bogoduhov, met by heavy AT gun fire. Elements of the 9th CD were late, and could not reinforce the successes of the tanks' assaults. At nightfall, the cavalry retreated to initial positions. The tanks could not remain close to the village without infantry cover.

Another assault was scheduled for October 14th. The tank brigade acted subordinate to the 9th CD, with an assignment to clear Bogoduhov, and link together the 5th CD and 108th Cavalry Regiment.

The advancing tank group did not encounter any resistance until 300-400 meters, at which they were faced with AT gun fire, and mortar fire at the cavalry. The tanks kept advancing, destroying a significant portion of the enemy's AT guns. The brigade captured the enemy's battalion HQ, and destroyed a large portion of the enemy infantry. At 22:00, left without cavalry support, 6th Guards ITB left Bogoduhov and returned to initial positions. 

The last attack on Bogoduhov was scheduled for October 15th. The objective remained the same. The enemy, unable to resist the attack, left Bogoduhov, abandoning their armament. The 6th reached the center of Bogoduhov. The 9th CD met heavy resistance, and could not advance. A flank attack from the west forced them to retreat. The 6th Guards ITB was ordered to withdraw and return to Sennoye. During these three days, the enemy lost:
  • AT guns: 16
  • 105 mm guns: 4
  • Trucks with ammunition: 1
  • Infantry: two battalions
We lost:
  • KV tanks: 2
  • T-34 tanks: 2

Friday 10 May 2013

Soviet Armour Quality

I've been focusing on German armour a lot, so it's only fair that I look at the quality of Soviet tank armour for a little bit. As we've seen, German armour quality post 1942 is quite brittle, with lots of spalling, cracking, and fragmentation going on. Let's see what Soviet armour is like in that regard.

CAMD RF 38-11355-785

In the NII-48 report "Penetrations of T-34s and reasons for their losses", a large number of knocked out T-34s were examined, for, as you may have guessed it, reasons why they no longer work. As well as offering a very interesting breakdown of calibers and impact locations, it also offers an analysis of armour quality. Let's take a look.

"6. Comments on the quality of armour on the T-34.

Existing data on impacts allows us to conduct an analysis of the armour used on the T-34. Table #25 shows information on the type of impact, and the caliber responsible for the impacts, in percentages."

The first line is "safe impacts", or non-penetrating hits. 54.1% of hits do not penetrate the T-34, this is pretty good. The rest of the line breaks it down by caliber: 3.2% by 20 mm shells, 6.8% by 37 mm shells, 4.9% by 42 mm shells, 30.6% by 50 mm shells, 3.2% by 75 mm shells, 0.2% by 88 mm shells, 2% by 105 mm shells, and 3.2% from indeterminate sources.

The next section is the one we can judge armour quality by. 42.0% of the impacts were clean penetrating hits. Only 2.1% of the hits were ragged (indicating impurity in the steel), 0.6% had cracks, 0.6% led to spalling, and 0.6% had fragments fall off. This is pretty good! The analysis agrees.

"It can be seen from the table that the percentage of brittle impacts (ragged penetrations, cracks, spalling, fragementation) is very small, 3.9%. Most of the brittle impacts are from artillery calibers greater than 50 mm, and from unknown sources, which could be bombs, grenades, mines, etc. Overall, the quality of armour is satisfactory. Judging the armour's resistance is not possible, since the ranges and angles of impact are not known."

NII-48 explores the topic in that last sentence in a different paper, and it will be the topic of another article.

Guardsmen in the Fall, Part 5: Battle at Shtepovka

"5. Battle at Shtepovka

The brigade left Padanki on the night of September 28th to 29th, and moved to north-east, concentrating in the forests west of Lifino, with one company remaining at Serobabino. 9th CD retreated to the Gostronurovo defensive line. 5th CD defended Mezherichi and Markovka. The 35th Motorized Division of the enemy, reinforced by a battalion of tanks from the 9th Tank Division, was located in Malinovka and further south along the river Suna.

The roads were muddy, and unsuitable for wheeled transport. The weather was cloudy, and it was raining. The brigade was ordered by Major-general comrade Belov to capture Shtepovka by the end of September 29th, and hold it until reinforcements from the 9th CD arrive at nightfall. Elements of the brigade approached Shtepovka at 23:00 on September 29th, crushed the enemy guard, and fought until 5:00 on September 30th. Without tank or cavalry support, they were forced to retreat to Yakovenki. Tanks and cavalry, due to the poor roads and dark night, were held up, and the mission was unsuccessful. 

Additional tanks were assigned to the 6th Guards ITB to attack Shtepovka and hold it, supported by elements of the 9th CD. During this operation, a group of tanks from the brigade noticed a column of 40 vehicles and enemy infantry, and attacked it. The enemy fled, leaving behind some vehicles, 15 dead, and one captured. At the same time, another column was spotted moving from Malinovka to Shtepovka. Taking fire from tanks and AT guns, the column was stopped and scattered. The enemy lost 3 tanks and 15 vehicles. 

At 16:00, the attack on Shtepovka began. Tanks and motorized infantry fought until nightfall. The enemy resisted, and forced us to retreat at 21:00. The enemy lost:
  • Vehicles: 40
  • Guns: 8-10
  • Infantry: two companies
Another attack on Shtepovka was scheduled for October 1st. After an artillery barrage, tank-borne infantry advanced on Shtepovka and destroyed a series of hardpoints, as well as infantry scattered through the village. At 20:00, Shtepovka was secured. The enemy lost:
  • Vehicles: 95
  • Guns: 60
  • Motorcycles: 20
  • Tanks: 8
  • Tractors: 18
  • Aircraft: 1
  • Infantry: two battalions
We captured: 
  • Light vehicles: 11
  • Heavy vehicles: 15
  • Tank machine guns: 8
  • Ammunition: 40 000 rounds"

Thursday 9 May 2013

Guardsmen in the Fall, Part 4: Battle at Mtenovka

"4. Battle for Mtenovka

After the battle at Vasilievka, the positions were as follows:
  • 9th CD was retreating from Kozelnoye to north-east, through Mtenovka to river Poei.
  • 5th CD was concentrated north-east and south-east of Padalki
  • 25th Motorized Division of the enemy moved to Shtepovka, in the direction of Sumy, on the morning of September 28th.
As a result of the enemy movements, the path of the 9th CD to Shtepovka was cut off, and they were in danger of being surrounded. The brigade received an order: attack through Podoprigory and Shtepovka, strike at the tank column, capture Shtepovka, and secure a path for the 9th CD to its assigned region.

A company of T-34 tanks and platoon of KV tanks, commanded by Colonel Dayev, followed the Nadanki-Podoprigory-Shtepovka route, and reached Shtepovka by 14:00. They suddenly opened fire on the enemy's column. The enemy, confused by the attack, left behind vehicle and guns, and fled, under fire from our tanks. Elements of the enemy forces at Mironovshina direction opened fire at our forces, but had no effect. 

The enemy was defeated. A path through Shtepovka was open for the 9th CD. The enemy lost:
  • Guns: 52
  • 105 mm howitzers: 12
  • Tractors: 8
  • Vehicles: 40
  • Motorcycles: 12
  • Tanks: 4
  • Infantry: up to a company
Our losses:

Wednesday 8 May 2013

Lend Lease Impressions: Churchill

Churchill III tank at the NIIBT proving grounds, September 1942. Retrieved from Baryatinskiy, Lend Lease Tanks in Battle.

The Churchill (frequently referred to as "Mk IV" in Soviet documents) was among the various tanks received by the Soviet Union through the Lend-Lease program. As with all tanks, they put it through trials, and, as with all tanks, it had some shortcomings.

CAMD RF 38-11355-938

"List of defects discovered in the process of using the Churchill tank.

  1. The track link pins on the new tracks are contained with welds. This makes it difficult to repair tracks in field conditions. After replacing track pins, it is difficult to weld the covers back in place. 
  2. Lightened tracks collect dirt and bulge out, which in turn pushes up the mudguards and make turning the turret difficult.
  3. Road wheels are poorly held on their axles. There were cases where they would come off and get lost during the tank's movement.
  4. The track link mortise is of poor quality, and is destroyed during movement.
  5. The main clutch gear axles are of poor quality, and sometimes break at their base.
  6. Rollers in the gear box are of poor quality and break.
  7. Gears in the gear box are of poor quality and break.
  8. Oil leaks from the gear box.
  9. The hoses from the "Amal" gasoline pump are not sturdy enough, and can tear during movement.
  10. The manual turret rotation mechanism is insufficiently reliable. The chain breaks, and the switch from manual to automatic traverse bends.
  11. The height of the driver and assistant driver observation devices does not let them see to the sides.
  12. The open engine grille does not prevent gasoline from incendiary bottles from getting into the engine compartment.
  13. Track links do not make good contact with the ground. The poor traction severely limits the tank's ability to go up and down inclines and tilt.
  14. Upon tilting 20 degrees, tracks fall off.
  15. The recoil springs of the 57 mm gun are poorly fixed, which leads to imbalances and jamming when they hit the cylinders."
In real combat, the Churchill showed another deficiency. The heaters were weak, and often replaced with domestic ones. 

That's quite a list. The Soviets weren't the only ones to dislike the Churchill, however:

"The reason that the Vickers company did not receive the contract to develop the Churchill is that when the head engineer of the company (responsible for the successful Valentine tank) saw the A22 project, he refused to have anything to do with it."

The opinion of the Churchill wasn't entirely negative. A report titled "Report on short trials of the English heavy tank MkIV Churchill on the Red Army NIIBT proving grounds" from September 16th, 1942, has the following to say about the Churchill:

"The MkIV tank has weaker armament than the KV-1 and KV-1S, but superior armour. The MkIV carries three times as much ammunition for its machine guns as the KV. The AP shell from the 57 mm gun penetrates all the way through a PzIII tank from the side, 60 mm of armour in total, at 950 meters. The MkIV has lower hp/ton, and therefore a lower maximum speed, than the KV-1 and KV-1S, but its average speed is equal. The MkIV and KV are equivalent in their operational range.
The English MkIV heavy tank is insufficiently reliable, and appears to be an unfinished vehicle, both from a design and construction standpoint.
The tracks create poor visibility for the driver and hull gunner. Periscopes do not improve this situation.
The gun length, when pointed forward, does not exceed the length of the mudguards. When the gun is fired in this position, the mudguards are bent and torn off.
The observation devices installed in the turret are satisfactory.
The engine is a modern design, and uses a small amount of metals in deficit, and is thus well suited for mass production. However, the engine is unfinished, and its reliability during use is questionable.
The transmission of the tank exists in one unit with the turning mechanism. The turning mechanism allows the tank to rotate in place, and to turn the tank easily, providing very good maneuverability for a heavy tank.
The suspension is not sturdy enough for a 40 ton tank. During the short trials, inner road wheels fly off the bogey axles, followed by outer road wheels, the bogey balancers start to rub against the tracks, and break quickly. The road wheel rims make contact with the tracks in such a way that both the tracks and wheels wear out quickly. This also leads to the road wheels heating up significantly during motion. The track pins are of poor quality and break."
Conclusion: the armour and armament of the English heavy tank MkIV Churchill is sufficient to fight any German tank. The MkIV is unrefined, both from a design and production standpoint. When used in the field, it will require frequent repairs, and replacement of parts and entire modules.

Several components of the tank (turning mechanism and transmission in one block, as well as others) are very original, and can be recommended for use on domestic tanks."