Monday 12 August 2019

5 cm KwK Penetration Tables

This booklet follows the same rules for penetration tables I posted previously. A black area indicates a vulnerable spot, shaded area indicates a spot that can be damaged, shooting at a white area will have no effect.


Traditionally, the T-34 is first. The "T 34 A" refers to a tank with a welded turret, the "T 34 B" has a cast turret. The cast turret appears to be more effective. The 5 cm KwK 39 L/60 is almost completely ineffective from the front: only a hit to the front of the turret with APCR (or in the welded turret's case, AP) from 100 meters will penetrate. The side of the tank is also tough: only AP or APCR at 100-200 meters will penetrate the side. Mysteriously, the added power of the cast turret's armour also affects the hull, as the T-34 A's side can be penetrated with AP from 100 meters and APCR from 200 meters. The T-34 B's side can be penetrated with APCR from 100 meters and not penetrated by AP at all. In both tanks, hitting the flat side armour will achieve a penetration from 500 meters with AP and 550 meters with APCR. The back of the turret has the same vulnerability as the sides. It's unclear if the Germans made a distinction between tanks with a gun service hatch in the rear and those without. The hull is immune from the rear.


Next is the KV series. The regular KV-1 is vulnerable to APCR from the front at a suicidally close range of 50-100 meters. The "KW I C", a KV tank with a cast armour turret and applique armour, is not vulnerable. Only shooting at the gun mount, hull MG, or driver's vision slit can disable the tank. The KV-2 has the same vulnerability as the KV-1, but the large flat section of the armour under the gun can be penetrated from 250 meters with APCR.

The side of the tanks is more vulnerable. The KV-1 and KV-2 can be penetrated from up to 250 meters with APCR. The KV-1 with applique armour is better protected. Only the hull armour is vulnerable, excluding areas with applique armour along the side. 

From the rear, the KV-1 and KV-2 are similarly vulnerable, with the back of the turret being the most tempting target. The cast turret of the KV-1 with applique armour is immune even from the rear. The gunner's only chance is to hit the lower rear armour or the simplified sloped rear armour (compared to the first KV-1's more elegant curve) with APCR. It is also possible to start a fire by hitting a small strip where the air intake is located.


Even though the manual was published in 1943 and the Matilda was not a common sight on the Eastern Front, it's still included in the manual. The tank is a little bit more vulnerable than the KV, but not by much. AP is still ineffective. Penetration can be achieved from up to 350 meters from the front if the driver's visor is hit, otherwise only from 100 meters if the face of the wedged armour is hit. The side is vulnerable from 100-250 meters. As expected, the spaced armour around the tracks absorbs even APCR very effectively.

The tank is vulnerable from 250 meters from the rear of the turret or cupola are hit. A lucky hit with HE to the engine deck can start a fire.


Moving on to the next British infantry tank, the Valentine. A note is made that this data is calculated and needs to be confirmed. Unlike the Matilda, the Valentine can be penetrated from the front at 100 meters with AP or up to 400 with APCR. The same goes for the lower side of the tank, penetration of the upper side is unlikely. The back of the tank is not much weaker than the front, vulnerable at 400-500 meters against APCR and 100 meters against AP. Again, a hit to the engine deck has a chance of starting a fire.


The Churchill III wraps up the infantry tank series, although a note is made that the Churchill I and II are subject to the same rules. The tank is a little tougher than the Matilda: its weakest spot can be penetrated from the front at 200 meters with APCR. From the side, the protection of the turret is slightly better than the Matilda, but protection of the side is much worse. A penetration can be scored from 300 meters if using APCR. If the strip above the suspension is hit, it can be penetrated from 200 meters with AP and 450 with APCR. Predictably, the rear of the tank is the weakest. The back of the turret can be penetrated from 300 meters with APCR (the Churchill I and II are actually tougher and can be penetrated from 200 meters). Fire to the rear of the tank is effective from 300 meters with AP or 550 with APCR. Since the engine deck is not sloped, the gunner is not instructed to set it on fire with HE.


Moving on to the Americans, the M3 Lee is much more vulnerable from the front. The turret armour and heavily sloped glacis are immune, but there are plenty of weaker points for the gunner to aim at with APCR or even AP. A hit to the sponson, which is a pretty large target, will be effective from 500 meters even with AP.

Similarly, the side offers a large and tempting target. Fire with AP is effective from up to 800 meters. Fire with APCR is effective from 550 meters, as this is the maximum effective range of this type of ammunition. The tank's rear is similarly vulnerable. It's possible to set the engine on fire by hitting the pocket between the air filters. 

The data for this tank is also calculated.


Last but not least, the Sherman tank. Like the T-34, the Sherman proves a formidable opponent from the front. The only weak area is the cast transmission plate cover. Firing at the bow MGs, air intake, and periscopes might have some effect. The manual depicts a very interesting tank: an M4A1 with bow MGs, indicating an early vehicle, but no DV ports or three piece transmission cover, which this type of tank should have. It's interesting that an M4A1 is depicted at all, considering that all Shermans the Germans would have met were M4A2 models.

From the side, the turret is vulnerable to APCR from 300 meters, the hull is vulnerable to AP from 400-800 meters (depending on where it lands), the APCR is effective from maximum range. The artist also hit a snag here, with some kind of doubled up return roller. 

The back of the tank is tougher than the Lee's. You can still light it on fire by hitting underneath the engine deck, but AP can only take it from 550 meters, and the vulnerable area is much smaller. APCR is also effective against that area, but other areas are available when firing from 300-400 meters. 


25 comments:

  1. Beautiful. Thanks for sharing.

    ReplyDelete
  2. So having a cast turret somehow increased the protection of the T-34s hull compared to the welded turret. I'm thinking that this German graph was more "guesstimates" as opposed to actual test results.

    ReplyDelete
  3. In terms of upper side hull differences between T-34A and T-34B: maybe later T-34 variant have 45 mm upper side hull thickness instead 40 mm? Some data show that T-34 (T-34-76) have 40 mm thickness of upper side hull, some 45 mm thickness. From other hand, maybe we have differences of armour quality...

    ReplyDelete
    Replies
    1. My presumption here is that the T-34B is meant to be the 42 model with the larger turret, which would explain the increase in height, even though the features still resemble the earlier turret.

      Delete
    2. The upper side was 40 mm until the T-34-85, when it was changed to 45. As far as I can tell, the difference between A and B is welded vs cast turret and one driver's observation device in the hatch vs two. The thing is that this classification makes no sense, since a) you can find tanks with either type of turret and driver's hatch and b) what classification is there then for a T-34 with the L-11 gun?

      Delete
    3. @Peter, I know opinion that T-34 (T-34-76) have 40 mm upper side hull... but I think that's not truth. As example, in British document about "Russian T/34" we have data which show 45 mm thickness of upper side hull thickness. I think that Soviets propably increase thickness of upper side hull to 45 mm before itroduction of T-34-85.

      Delete
    4. Possibly, I do recall about rationalizing the thickness of plates to only a few thicknesses, so the distinction between 40 and 45 mm would probably be the first to go.

      Delete
  4. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. The Sherman's front turret is 76 mm: better than a T-34-76, but not as good as late model T-34-85s (90 mm).

      Delete
    2. I've reading through the "Servicing and Repair manual for T-34/85 tank and SU-100 SPG", looking for some useful information, and came across an interesting schematic:
      https://imgur.com/mOV7Qbc

      Thankfully the scan is pretty high resolution. Doing some pixel measuring and assuming that the thickest pat of the external mantlet is exactly 90mm, I came up with the following dimensions for other parts (with some rounding assuming that they are all multiples of 10):
      https://imgur.com/h7Bk30V

      So, the cylindrical part seen in this photo is 30mm, with a 20mm splash shield(s) covering the hole(s).
      https://imgur.com/BIlKotS

      This arrangement wont be as protective as a single plate of sum of their thicknesses(90+30mm) but still the mantlet area of T-34/85 probably has the equivalent thickness of around 100-110 mm.

      Delete
  5. As I supposed the M4 turret front offer better protection than that on T-34 which probably relate to the more factors like thickness, overlaps, slopes and better protected recoil brake. In T-34-85 and IS turrets was improved housing of the gun and center of the gun shield was no more such weakspot.

    ReplyDelete
  6. I assume this is the 5 cm. KwK 38 but I don't know. The Yugo tests has the 5,cm PaK vs T-34 and it has a lot longer side penetration. The German criteria cannot be that much more stringent than the Yugo criteria.

    ReplyDelete
    Replies
    1. It's indeed for the 5cm KwK 38 and not the long barreled 39.
      Otherwise it could only penetrate the Sherman side turret from 100m. The Valentine's front and side can also only get penetrated at 400m while the KwK 39 penetrates more than 60mm at 30° at 500m.

      Delete
    2. Didn't you see the model and the data in the first page of the document?

      Delete
    3. It reads 5cm KwK 40 but there was no 5cm KwK 40.
      The first 5cm KwK was the short barreled 5cm KwK 38.
      Since the penetration ranges are too short to be for the long barreled gun and 5cm KwK would refer to the short barreled gun, it's either infact for the KwK 38 or they simply underestimated the penetration ranges for the long barreled gun.
      They might have taken the penetration data, which is against 30°, and treated them as if they were 0° and converted them again to 30°. However it's not really clear to what gun this guide is refering to.

      Delete
    4. Implying that the Germans themselves don't know how to use their own tables is a pretty shaky claim.

      Delete
    5. German penetration tables were quite pessimistic. They are the minimal engagement distances at where penetrations are basically 100%. They always consider that the armor plate is angled 30°.
      This caused some confusion among troops since practice showed that tanks could be penetrated at much longer range than the anti-tank "guide" predicted.
      In later reports this is clarified and that under optimal circumstances, ergo the plate is shot directly from the front, the penetration distance would be higher.

      Delete
  7. The M3 and M4 having different values for the hull sides and rear is an obvious tell as well for guesstimating as they should offer up roughly the same 1.5 inches of protection in those areas.

    ReplyDelete
    Replies
    1. I believe that the chart is computed with assumption that M4 Sherman tanks have 2,5in. of upper side armour. The ballistic limit for the 5cm Pzgr.39 for that thickness at 30° is about 735m/s, almost exactly its terminal velocity at 400m(730m/s).

      Delete
  8. It looks like the maximum range for the HK -APCR is 550 m no matter what the target.

    ReplyDelete
    Replies
    1. Maybe due aerodynamics of early German APCR? I found opinion that during WWII, due to bad aerodynamics, early German APCR and Soviet APCR, at big distance, have worse penetration than typical full caliber AP.

      Delete
    2. Wouldn't that be already because a lighter projectile (part of the whole point of the APCR design, in order to amp muzzle velocity) loses energy faster? Same basic reason why the 122 mm beat the 100 mm at extended ranges.

      Not that most of the newer and fancier shell designs of the day weren't in varyingly acute need of product improvement ofc. *eyes British APDS accusingly*

      Delete
    3. @Kellomes: You have a right, smaller weight of APCR also have conotation with smaller penetration at big distances (smaller than in typical AP), but due opinion which I found, this situation is more visible in early German APCRs and Soviet APCRs, which use non-optimal design from earodynamics point (in Poland we use "spool-type" term for this early APCRs).

      Delete
    4. Yes, that is true. The APCR loses penetration faster than full size AP. APCR still penetrates more out to about 950 m.
      APCR also has about twice the dispersion as the regular shell.
      Though with the higher velocity still results in a higher percent chance to hit at 1000m.

      Delete
    5. 550m is around the range where the 5cm Pzgr. 40 has the same penetration as the 5cm Pzgr., at least according to the German penetration data for 30°. However the Pzgr. 40 probably still has more penetration than the regular Pzgr. when striking vertical armor.

      Delete