Jump to content

StuG III Thread (and also other German vehicles I guess)


EnsignExpendable
 Share

Recommended Posts

Boxer JODAA technology testbed/demonstrator made by Rheinmetall for the Bundeswehr. It allows the commander to take over the driver's control digitally from his position. The vehicle can release UAVs and UGVs carried inside without the need of manual assistance or the need to leave the vehicle. The UAVs and UGVs can be remotely operated from inside the vehicle. The Boxer JODAA can also be controlled remotely.
 



SPRINT_JPW_01.jpg
 
Boxer JODAA - Wiesel 2 WITCH - Panther
 


27522971812_bc55c64c36_h.jpg
 
Side view of the Boxer JODAA
27522970682_613aaa3066_b.jpg
 
Camera systems on the driver's hatch.

maxresdefault.jpg
 
Automated release of a UGV (anti-IED robot in this case).
 
q0TJFB9.jpg?2
JODAA mark 2? ;)

Link to comment
Share on other sites

I wonder if they ever found the suspension components.

Yeah, attached to the hull  :huh:

 

 

I've never been clear on why the E-100 was called that.  It didn't have the same belleville washer suspension as the other E-series tanks, which was supposedly the reason they were all called that.

Well E-100's design is jumbled due to the fact that it aped off the Tiger-Maus, and received incremental design changes/proposals all the way to the end of the war

Link to comment
Share on other sites

I wonder if they ever found the suspension components.  I've never been clear on why the E-100 was called that.  It didn't have the same belleville washer suspension as the other E-series tanks, which was supposedly the reason they were all called that.

 

Panzer Tracts gives the impression that it was done for purely political reasons in order to get it funded.

Link to comment
Share on other sites

I ended up doing a data dive on the 2-pounder (specifically: why the hell every wargame ever gives it 80mm of penetration at the muzzle when it barely managed 50*) and ended up finding a wonderful tidbit in this compendium:

 

If we compare figures for the 76mm F-34/Zis-3 (pages 4, 10, 11, 16, 19, 20 and 23) and the Pak 36® (pages 5, 9, 12, 22, 24, 30, 32, 33 and 36), we find some interesting discrepencies:

  1. These guns never seem to end up in the same table together, despite being essentially the same damn gun ballistics-wise.
  2. All of the figures for AP performance hover at 60-70mm at 500m/30' angle for the former and 90-110mm for the latter.

From the above, we may conclude only one thing: having a German touch your gun will up the penetration by 50%.

 

 

*The answer, as they say, may surprise you.

Link to comment
Share on other sites

From the above, we may conclude only one thing: having a German touch your gun will up the penetration by 50%.

 

Maybe the wargamers fail to take the different penetration criteria into account? Also the Germans used their own APCBC PzGr. 39 and PzGr. 40 ammunition, whereas the BR-350A was simply an obsolete design, relying on a flat-nosed AP projectile without cap or dampers.

 

1071625.jpg

 

EDdh6bG.png

Link to comment
Share on other sites

Yes, that's pretty much exactly what has happened. And no, a APBC versus AP won't get you 50% improved performance.

 

 

Sure, going from AP to APCBC does not increase performance by 50%. However there are mutliple other factors directly affecting the penetration difference between the types of ammunition. The German propellant lead to a slightly higher muzzle velocity, APCBC performs better against sloped armor (both penetration values are for 30° sloped plates), the PzG. 39 has a better aerodynamical shape and a larger steel core (with a smaller HE filler).

According to David R. Higgins' "King Tiger vs IS-2: Operation Solstice 1945" early Soviet ammunition used rather soft steel cores, so that the penetration of the BR-471 APHE round improved by 9% just by using harder steel. Given that the BR-350A is a very early Soviet round, I wouldn't be suprised if it used even softer steel than the early BR-471.

 

All these factors might only affect the penetration by a few percents, but they all add up. 50% improved performance might be a bit too much and also affected by different penetration cirteria, but the 7,62 cm PaK 36 ® is launching a larger projectile with better shape at a higher velocity... expecting the same penetration values for both guns firing different ammo is wrong.

Link to comment
Share on other sites

Apparently later PAK 36 ® were rechambered for more powerful ammunition.  That strikes me as the most likely explanation.

 

I'm dubious that the German powders improved velocity all that much.  The main difference between German propellants and everyone else's is that the German gun propellants contained nitroguanidine.  This reduced muzzle flash considerably (presumably due to better oxygen balance), but I don't buy that nitroguanidine would improve muzzle velocity by simple substitution in an already existing gun.  For one thing, nitroguanidine has an energy density of 8.4 KJ/g versus 9.1 for nitrocellulose.  Adding it to a propellant would make it somewhat less powerful, not more powerful.

Link to comment
Share on other sites

I don't think you should judge the performance of a propellant based on a single component. There were numerous differnet variations of propellant being used by every country in the war, the British Army used at least thirteen (!) different types of propellant thoughout the second world war.

 

My statement about the propellant is based on the fact the the PaK 36® is firing a heavier projectile (if the values from other forums are correct) at a higher muzzle velocity. I have found a number of references (e.g. in webforums and books like "The Encyclopedia of Weapons of World War II and others") about different guns gaining performance after changing the powder composition, including some Soviet ones (in the late 1930s and in the 1940s new propellants lead to increased performance). The BR-350A is a very old Soviet round, the 7,62 cm PzGr 39 is a newer design. The Germans adopted the PaK 36 ® about five years after the original gun entered service with the Red Army... there is plenty of time to have developed better propellant systems.

 

___

 

Wisent 2:

 

zoom_680x510_wisent2-07.jpg

 

zoom_680x510_wisent2-08.jpg

 

zoom_680x510_wisent2-09.jpg

 

Wisent 2 hull welding:

 

Teaser-Wannenbau-_3_.jpg

 

Teaser-Wannenbau-_7_.jpg

 

Teaser-Wannenbau-_8_.jpg

 

Teaser-Wannenbau-_1_.jpg

 

Teaser-Wannenbau-_6_.jpg

Link to comment
Share on other sites

I don't think you should judge the performance of a propellant based on a single component. There were numerous differnet variations of propellant being used by every country in the war, the British Army used at least thirteen (!) different types of propellant thoughout the second world war.

 

My statement about the propellant is based on the fact the the PaK 36® is firing a heavier projectile (if the values from other forums are correct) at a higher muzzle velocity. I have found a number of references (e.g. in webforums and books like "The Encyclopedia of Weapons of World War II and others") about different guns gaining performance after changing the powder composition, including some Soviet ones (in the late 1930s and in the 1940s new propellants lead to increased performance). The BR-350A is a very old Soviet round, the 7,62 cm PzGr 39 is a newer design. The Germans adopted the PaK 36 ® about five years after the original gun entered service with the Red Army... there is plenty of time to have developed better propellant systems.

 

 

 

 

 

It's perfectly reasonable to judge two propellant blends when the only difference is the presence or absence of nitroguanidine.  And in this case it is.  Propellants are mostly nitrocellulose in the case of single base propellants, a mix of nitrocellulose and nitroglycerin in the case of double base propellants, and a mix of nitrocellulose, nitroglycerin and nitroguanidine in the case of triple base propellants.  A few percentage points of the mass are taken up by anti-static agents, burn rate modifiers, wear reducing agents, stabilizers and other stuff.

 

Nitroguanidine would allow for slightly better muzzle velocity if the constraining factor on the performance of the ammunition were bore wear.  Nitroguanidine reduces the peak flame temperature without compromising the pressure very much.  So if the gun had a breech design that had excessive safety margins but were designed for very long bore life it would be possible to substitute triple base propellant and cram in a bit more powder.  Bore wear would stay about the same, but there would be a slight boost in performance.  But nitroguanidine doesn't have any more energy than other propellants, quite the opposite.

 

This isn't the same thing as saying that the new powder provided that performance.  Gun performance for large caliber systems is primarily constrained by the strength of the gun.  There is a lot of fuzzy thinking that has leaked in from the small arms world where the breech mechanisms are extremely overbuilt and people can get away with not knowing what's really going on.

 

The kinetic energy of the projectile will equal the integral of the pressure curve at the base of the projectile as a function of travel down the barrel times bore area.  Simple calculus, simple thermo.  There are many complex factors that go into exactly what the shape and magnitude of that pressure curve is, but bottom line is that integral equals muzzle kinetic energy of the projectile.  Always.

 

What that means is that pressure is what makes the projectile go.  So, to a very reasonable first approximation, if the propellant doesn't have more energy, it won't make more pressure, and it won't make the round go any faster ceteris paribus.  If you get new ammunition that does have more pressure and it doesn't explode your gun it's because the gun was overbuilt for the original ammunition.

 

But there's very little room in this equation for some sort of new propellant that has the same peak pressure as an older propellant, but that somehow produces more muzzle energy.  It's possible, but it would take an extremely contrived situation to actually be realized.

Link to comment
Share on other sites

Apparently later PAK 36 ® were rechambered for more powerful ammunition.  That strikes me as the most likely explanation.

 

I'm dubious that the German powders improved velocity all that much.  The main difference between German propellants and everyone else's is that the German gun propellants contained nitroguanidine.  This reduced muzzle flash considerably (presumably due to better oxygen balance), but I don't buy that nitroguanidine would improve muzzle velocity by simple substitution in an already existing gun.  For one thing, nitroguanidine has an energy density of 8.4 KJ/g versus 9.1 for nitrocellulose.  Adding it to a propellant would make it somewhat less powerful, not more powerful.

You are correct - supposedly some later ones were rechambered. Edit: which is to say that you are probably right here.

 

It's still very interesting (read: I'm going to carry on digging this hole regardless) that you simply can't find side-by-side comparisons of both guns using the same testing methodology. What you can do is check PaK 40 penetration when tested by the Soviets and Germans, respectively.

 

Lo and behold, the Soviet methodology has a penetration of 103mm at 100m against a vertical plate. The equivalent german figures are 148mm (PzGr 39) or 174mm (PzGr 40). Which is almost the exact same discrepency as between the Soviet measurements of the F-22 and the German measurements of the PaK 36®.

 

Again: having a teuton touch your piece will up the penetration by 50%, if you are so simple as to just take the measurements at face value.

Link to comment
Share on other sites

I don't think you should judge the performance of a propellant based on a single component. There were numerous differnet variations of propellant being used by every country in the war, the British Army used at least thirteen (!) different types of propellant thoughout the second world war.

 

My statement about the propellant is based on the fact the the PaK 36® is firing a heavier projectile (if the values from other forums are correct) at a higher muzzle velocity. I have found a number of references (e.g. in webforums and books like "The Encyclopedia of Weapons of World War II and others") about different guns gaining performance after changing the powder composition, including some Soviet ones (in the late 1930s and in the 1940s new propellants lead to increased performance). The BR-350A is a very old Soviet round, the 7,62 cm PzGr 39 is a newer design. The Germans adopted the PaK 36 ® about five years after the original gun entered service with the Red Army... there is plenty of time to have developed better propellant systems.

 

Adding to what Colli said: the information I could find on the PaK-36®* shows that it chucked a 1kg heavier projectile with an extra 40m/s of velocity. Plug all of this, along with the Soviet tests for the F-34, into a penetration calculator and DeMarre will give you a value at 100m of 101mm. You can also sanity-check the data by comparing it with the same calculated values for PaK 40/PzGr39 (103mm estimated) and then use the same test results to show that the model is correct (103mm measured). This means that, even if you assume the bigger cartridge, the values for PaK-36® should be more in the region of 100mm at 100m/90'. Which is, again, just another long-winded way of saying that the German methodology gives penetration results about 50% greater than the Soviet methodology. Which is, again, just a way of warning people to be careful before jerking off to the idea that the Germans had some sort of magic lock on AT guns.

 

Playing the same game using German methodology, by the way, shows the mighty F-34/Zis-3 penetrating 95mm at 500m/90'. Which means that Tigers getting ganked from the side using BR-350 at combat ranges is exactly in line with German expectations.

 

 

* Which actually seems to be the designation for the rechambered F-22 conversion only, but has seeped backwards to describe the guns as orginally captured/reworked.

 

Edit: this sort of thing is the reason I get so worked up about this. A handy penetration chart generator, well-designed and easy to use. And it uses the Soviet penetration figures for Soviet guns and the German figures for German ones. Which, if you play around a bit, would give you the impression that Tiger 1 simply could not be penetrated by T-34 at any distance (2 pounder, of course, has a good chance out to 200m). Which is ahistorical crap.

Link to comment
Share on other sites

Collimatrix, your post is based on the assumption that the propellant consists of the same components at the perfect mixture, only with one single different ingredient. If you can provide the exact compositon of the propellants used in said ammunition, I won't have an issue with your claims and agree with them.

 

However from the data available to me - and that is unfortunately neither the composition of German nor Soviet propellants, show that there is a much greater room for modifications. Some British propellants were composed of more six or more different materials, not just two or three. This means that the impact of replacing a fraction of one component with another might be a different than expected.

In the Cordite propellants, both raising and decreasing the amount of nitrocellulose could improve peformance - at least this is the case when comparing Cordite formula B with the original Cordite Mk. 1 and the Codrite formula C. At least the British propellants using nitroguanidine still had a small amount of nitrocellulose in the composition.

 

All that said, I'd like to point to the drawing I previously posted. It is from the official data sheet from WW2. As you can see it says in regards to the propellant charge: "Ladung zu etwa 2,6 kg Digl. R. P. - G 1". The "Digl" means that the propellant consists of Diglykol (diethylene glycol dinitrate) and nitrocellulose, together with centralite and sometimes potassium sluphate. It does not contain any nitroguanidine. The "R.P." describes the shape of the propellant (tube propellant). In so far your criticism of the German propellant is not appropriate in this context.

 

 

Toxn, as previously said: I do believe that the 50% greater penetration is also the result of the different penetration criteria. However I don't think that one should ignore the other factors, which I previously mentioned - just increasing the hardness of the steel cores could improve penetration of certain Soviet ammunition by 11%. Comparing the Soviet test results for one German gun to the formula from DeMarre only shows that it is valid for German (APCBC) ammunition. It does not guarantee the same level of accurateness when it comes to pre-war Soviet ammunition designs using flat-nosed projectiles against 30° slope. Specifcialyl against sloped plates DeMarre's formula becomes more inaccurate. There are reasons why DeMarre's formula (aswell as Krupp's formula) was discontinued (in the US at least) after comparing the results to actual ballistic tests made by the US Army and US Navy.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...