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.


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.

30 comments:

  1. Reloading times in british trials include a 2.4 second average for throwing the casing, and document implies that rounds were all fired.

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    1. Shh. Don't tell 'em!

      And than Peter wondering why he get called biased when he throws stuffs like this out of his ass:

      "Note how the action evaluated here is only loading; not firing, not extracting, not aiming." Link: http://forum.warthunder.com/index.php?/topic/290322-155276-d-25t-rate-of-fire-is-undermodeled/?p=5650829

      Or no with: "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"

      You can do it better Peter.

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    3. "Open clips"
      "Procure round"
      "Bend down and load"
      I don't see anything about throwing the casing.

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    4. Apparently nobody here can read or do simple addition. There is no value or column header in those tables adding an additional 2.4 seconds for throwing a casing.

      The table only records the results of, as Peter said:
      "Open clips"
      "Procure round"
      "Bend down and load".

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  2. http://i.imgur.com/RDC3kJv.jpg

    This is relevant passage reffering to extraction time, which logically implies that shells were fired.

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    1. I bet he's going to remove that comment too.

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    2. "This comment has been removed by the author." Means that the person who wrote the comment delete it. If I delete a comment, it disappears forever with no trace.

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    3. The actions performed in these trials are quite clear:
      "Open clips"
      "Procure round"
      "Bend down and load"

      Yes, maybe they fired the gun, but you can plainly see that only the time for these three actions is recorded. No figures have an extra 2.4 seconds added to them.

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    4. Document clearly states that a loading aid was used, it discussed the use of gloves, and that it took on average 2.4 seconds to discard the shell casings. And of course the a brief description of loaders A and B. Firing the KwK 43 with a casing hanging from the breech lip would be quite catasthrophic for the crew.

      http://imagizer.imageshack.us/v2/800x600q90/661/nar4vQ.jpg

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    5. If shells were fired, then we get the following sequence of events:
      Open clips: 2.0s
      Produre round: 1.5s
      Bend down and load: 3.6s
      Aim and shoot: some amount of time
      Throw away the casing: 2.4s

      2.0 + 1.5 + 3.6 + 2.4 = 9.5, so that's at the very least ten seconds to fire. How can a tank that takes ten seconds to fire shoot 10 times per minute?

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    6. Actually, the average time with one of the loaders was 8,0 seconds. Some time could be saved by knocking the casings down to the turret floor instead of throwing them out of the roof hatch.


      And its 6-10 rounds per minute. 5.7 was obtained with aimed fire trial.

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    7. "And its 6-10 rounds per minute. 5.7 was obtained with aimed fire trial."

      It is entirely possible to have 8s even on a aimed firing trial as the british motion study suggest. That's is only a whooping 2 seconds faster as his russian fellow.

      http://tankarchives.blogspot.be/2015/03/tiger-ii-trials-gunnery.html

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  3. "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. "


    Data in that documents is a cyclic rate of fire.

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    1. Really, where does it say that? Why would the Tiger II's cyclic ROF fire so greatly?

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    2. I don't see TIGER I or II mentioned, only KwK 36 or 43. That's the guns cyclic rate, practical would depend on the actual installation. See also RoF of the D-25T in the cramped IS-2 installation...

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    3. The KwK 36 and KwK 43 were installed in only one tank each. FlaK and Pak versions of these guns have their own page. The pages for vehicles in that document does not list RPM.

      I don't see what the D-25T has to do with this. It is not present in this document.

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    4. The error is then in understanding the source. The document lists the possible RoF possible and allowable with the gun (KwK 36 1 min remark is revealing). Guns are also AFAIK limited by how much the recoil mechanism can handle.

      Nothing in that document says its what was measured with an actual loader with a gun installed in an actual tank. I am sure there are German trials for that, but this seems to be a short listing of weapons and their costs (including strategic materials, so this one probably prepared for planners, rather than soldiers).

      In short, you are comparing apples and oranges. Guns will achieve different rates of fire when on a test stand, when in a cramped tank, when in an open artilerry installation fed by for example multiple loaders and different in a spacious tank and different in a cramped tank, different with rounds from the ready racks. Ammunition placement and confinement of tank interior, loader. Same goes for the D-25 variants which had far lower RoF when installed in actual, compact size tanks then in artillery pieces.

      I am not sure what you are getting, but if you are trying to discredit German sources as propaganda, you are doing a poor job... you only show that you do not understand the source.

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    5. "Really, where does it say that? Why would the Tiger II's cyclic ROF fire so greatly?"

      Because every other weapon in that document has a rate of fire consistent with what other source claim as a cyclic fire rate, for every I bothered to check.

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    6. Why did you assume I was trying to discredit German sources as propaganda? My thesis is clearly "10 RPM is impossible to achieve with a Tiger tank", which you seem to agree with.

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    7. >Because every other weapon in that document has a rate of fire consistent with what other source claim as a cyclic fire rate, for every I bothered to check.

      The 5 cm Flak 41 entry has 130 RPM listed, whereas the cyclic rate of fire is 180 RPM, and that's just from me picking one at random. What guns, specifically, did you bother to check, if I may ask?

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    8. Oh, and while you're at it, explain why the 8.8 Flak 36 gets 20 RPM while the tank version gets 10 RPM.

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    9. "The 5 cm Flak 41 entry has 130 RPM listed, whereas the cyclic rate of fire is 180 RPM, and that's just from me picking one at random. What guns, specifically, did you bother to check, if I may ask?"

      Just noticed the anomalies.

      SPzB 41 and KwK 42/L70 have practical rates of fire listed.

      I expect that 130 RPM for Flak 41 is the practical rate of fire, too.

      "Oh, and while you're at it, explain why the 8.8 Flak 36 gets 20 RPM while the tank version gets 10 RPM."


      Because the expected crew for KwK 36 would be 5 people with 1 loader, and average crew for Flak 36 is 10 people with 5 loaders.

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    10. Cyclic rate of fire measures how fast gun mechanisms work, why would loaders be involved in this operation? I am also questioning the value of stating the cyclic rate of fire for a single shot weapon in the first place.

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    11. "Cyclic rate of fire measures how fast gun mechanisms work, why would loaders be involved in this operation?"

      They obviously were in this case, otherwise both KwK and FlaK would have 20 RPM.


      " I am also questioning the value of stating the cyclic rate of fire for a single shot weapon in the first place."

      I wasnt aware that cyclic rate of fire is reserved for automatic weapons.



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    12. I'm not familiar with a definition of cyclic rate of fire that involves a loader's participation. First you say that it's obviously cyclic, then you say that loaders were obviously involved, you're making a lot of assumptions that are not supported by the document at all.

      Also I'm not saying it's reserved for automatic weapons, I'm just saying it's not a particularly useful value for something where a loader has to load every shell manually.

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    14. "I'm not familiar with a definition of cyclic rate of fire that involves a loader's participation. First you say that it's obviously cyclic, then you say that loaders were obviously involved, you're making a lot of assumptions that are not supported by the document at all."


      Thats what document states.

      It provides cyclic rates of fire for things like MGs and MPs, with occasional practical rate of fire like SPzB and KwK 42. And it differentiates between StuKs, PaKs and FlaKs, and even differentiates between the different version of the same gun.

      Largely small differencies in breechblocks wouldnt account for such a big differencies in fire rates, so the only probable explanation is that Flak fire rate was obtained with a human chain in between the gun and ammo dump, and KwK was done with one loader.

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    15. Which is exactly what I'm saying, the values in the document aren't just how fast the mechanism can go for these guns (which is what a cyclic ROF is), but how fast it can go in practice. What the article is saying is that the number the Germans end up with is still very far from a practical rate of fire in combat.

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    16. I also enjoy how you wrote that comment, submitted it, deleted it, logged out, and then wrote the same thing again as anonymous. Kind of defeats the whole point, no?

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