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4 hours ago, SH_MM said:

 

Side skirts are 65 mm.

 

 

 

You are correct I measured just to the mounting bracket on the top end, Looking at my picture I see the error now.

 

4 hours ago, SH_MM said:

 

Side skirts are 65 mm.

 

 

That depends on a lot of factors. The steel simulators are smaller than the actual turret frontal surface and there is also the option that some of the extra weight was used to improve the side armor of the turret, in order to keep a homogenous protection level at the frontal arc.

Qxg4e6P.png?1

 

There are also the curious case of (some of?) the other M1E1 pilot(s) having much thinner weight simulators:

 

 

There were probably lots of testing models seeing how much weight they could add progressively.

 

The 2.5' (estimate) plate, seems to cover most but not all of the area. It seems safe to assume that a good chunk of the weight goes into the extra structural armor, side armor, extra mounting brackets. That said 50-70mm of extra steel mass seems reasonable. The efficiency ME / TE increase vs KE vs BRL-1 is all conjecture at this point. Perhaps ~10% ME, seems reasonable based on increases of efficiency over the time period and era.

 

As has been said before by many, I feel like the RHA way of describing things is more the way for technical information being conveyed in a simple way to non technical people.

 

For example, the armor of a M1A1 with BRL-2 seems to be in the CIA document `~400mm across the frontal arc.  This isn’t an exact number but describes the type of weapon that tested against reliably defeats.

APFSDS are defeated in spaced composite arrays by being fractured and yawed and then the remaining elements being defeated by the back plate array. Rod design and dimensions seems to be more important then velocity in such a case. Eg (BM-22)

 

What I suspect is that the 400mm figure M1A1 with BRL-2 was tested successfully against APFSDS that pen around 400mm @ the impact angles approximating head on shots in the vertical from 25-30 deg in the Hz arc.

 

I suspect BRL used something like an M833 ( pen 380-400mm RHA ). This round was shot at different velocities at the armor package and found to offer reliable protection against a round of these dimensions and impact velocities. With the speed of the round being the least important variable.

 

So the statement means more accurately BRL-2 protects against DU monoblocks around  430mm x 30mm @ 1500 m/s. Because the statement was not say 480~ mm we can assume that longer rods at higher velocities defeat the packages (M829).

 

If what does this mean with regards to 125mm ammo BM-32-BM-42. These seem to be inferior round designs against spaced armor arrays. Superior against RHA yes, but against such arrays I have my suspicion that the increase in velocity may not overcome the limitations with regards to round design.  Again BM-42 seems to suffer against spaced armor arrays vs BM-32 for example. Could it be the armor arrays the BM-42 was designed against are as follows bellow.

 

19 hours ago, SH_MM said:

Andrei_bt once posted a drawing showing how the Soviets believed the MBT 80's armor would look like during the 1970s. I.e. the frontal armor was believed to be a sandwich of steel, aluminium-oxide, normal aluminium and steel.

 

 

That said I would not be surprised to find out that elements in the Bm-42 design allow it to overpass some spaced armor arrays.

 

5 hours ago, SH_MM said:

BRL-2 predates the use of tandem shaped charge warheads. The armor was finished before 1984 (when the M1IP entered service), the first Soviet tanks with Kontakt-1 ERA were fielded in 1983. The first NATO missiles with tandem warheads also entered service after the M1IP (BGM-71E TOW-2A: 1986, MILAN-2T: 1991, HOT-3: 1998, etc.).

 

The more reliable values (CIA estimates, values included in an article in a US Army magazine) I've seen suggest a hefty increase in protection against (single stage) shaped charge warheads: i.e. 900 mm instead of 700 mm steel-equivalent protection.

 

I am recalling from memory a thread some years ago on tanknet where it was discussed that tandem shaped charges were experimented on in the 1970s but left on the sidelines, however it was found they had improved performance against the newer armor arrays at the time.  I am open to correction on this of course. 

 

I suspect the statement of 900mm means defeats Tow-2 and perhaps Hellfire A type warheads tested against it.

 

Thanks for your thoughtful response as always.

 

 

 

 

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It's interesting. Presentation (which contains this page) which available now on ontres.se is 110 pages long about 2-and-a-half years ago i've downloaded on my computer presentation which was 119

Waffentrager YOU FAKE BULLSXXT and FXXK OFF In case you guys here cannot read Japanese: It says "Height of lens assembly is about 380 mm" May be taken from a manual of digital came

I don't think there is a possible explanation, because people are beginning the argument from the wrong direction. People are making assumptions about the protection level, then try to find sources su

  • 2 months later...
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Looks like the "human loaders are just as fast as auto loaders" is finally over. It seems like the Type 10 has two settings similar to the Leclerc's "Doublement" mode.

 

Looking at patents for the auto loader system Japan uses, the next round seems to drop off the ammo belt onto a feed ramp. my best guess for how the 1.6 seconds is achieved is a button is pressed where immediately after the first round is loaded, a next round is dropped off and prepared. As a result you get a faster overall reload, but lose the ability to switch ammo type in between shots. Otherwise you get a standard reload of 3 seconds, but the next round isn't immediately prepared giving time to switch ammo type.

Spoiler

Image

 

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7 hours ago, Atokara said:

Looks like the "human loaders are just as fast as auto loaders" is finally over. It seems like the Type 10 has two settings similar to the Leclerc's "Doublement" mode.

 

 

 

Assuming the barrel movement is in fact indicative of a reload, the reloading method you describe is the equivalent of a human loader holding the next round to be loaded in their lap.

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13 hours ago, Ramlaen said:

Assuming the barrel movement is in fact indicative of a reload,

Rule of thumb for any autoloader, no matter the country or design. As soon as the barrel moves, the reload is complete since any movement during the loading process would just sheer off any feed arm/ramp.

 

13 hours ago, Ramlaen said:

the reloading method you describe is the equivalent of a human loader holding the next round to be loaded in their lap.

An autoloaded version of a lap load is actually a really good way to describe it.

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There seems to be a difference between Bustle and Crew Area's Side Armor in Abrams Turret.

 

 

  • protection difference

c4zSTfs.png

 

 

Bustle Side : 90°, CE 380mm

Crew Area Side : 45°, CE 380mm

 

 

 

  • Plate thickness difference

fyL5CtR.jpg

 

Bustle Side : 6.35mm (¼ inch)

Crew Area Side : 19.05mm (¾ inch) 

 

 

 

ZilEvpE.png

 

"Bustle Side"

 

 

 

enmDJeU.jpg

 

exposed layout of bustle side armor
 

 

 

X8y35ZT.jpg

 

crew area side armor layout
 

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On 9/8/2020 at 10:22 AM, Wiedzmin said:

JNHREFA3O6I.jpg

 

some of my estimations on M1(M1 105mm) left turret frontal part, used all known and available data at the moment and some photogrammetry of real M1 from museum...

This is mostly wrong dimensionally and conceptually.
Where to start... I am guessing that you are basing your drawing on Gaijin's measurements of the Minnesota Abrams combined with the CIA drawing of the hull front armor? First of all I am sure they got the front armor volume wrong because they thought they measured from the edge of the internal armor plate sticking out through the underside of the turret on the right side. However this is a miss conception we can easily see this in images from the underside during production. What they are actually measuring from is the "armor floor plate" the plate that carries the armor, that is why we don't see any weld lines and it is curved rather than sharply angled like two welded RHA plates would be:
iBHzdE.jpg

This points to another misconception about the Abrams front turret armor rear plate, that it is monolithic. However it is not a straight copy an past of the hull front armor, rather it is a mix of front and bustle armor. The Abrams is rather similar to the Leo2 in this regard. A "thin" back plate to maximize the adjustability of the armor protection. Here the similarity ends, because to this back plate bolts can be fastened enabling you to mount the number of armor plates needed to reach the desired protection level.
HRJu95.jpg

So how can we estimate the LOS of the Abrams turret front? Well we go back to the front hull and fist we get the right dimensions from that. Now I happen to have the exterior dimensions of the Abrams, but we could scale of the dimension that Gaijin have provided us of 22" from front to start of back plate. And in the end up with a Armor LOS of ~650mm which is a damn coincidence cause that is also the LOS of Leopard 2 hull armor(and turret I estimate). So now we know the minimal LOS needed with Abrams armor to meet the armor requirements of 322mm+ KE/ 636mm+ HEAT.

Given that the turret had to meet at least this same requirement we can just add ~650mm LOS to the side of the left turret cheek at the correct angel. Here I am unsure whether they went with 25 or 30 degrees but it actually don't make much difference, what you end up with is a ~800mm frontal LOS with either. But now we know the frontal LOS which by the way is roughly in the middle range of the Gun Shield LOS of 710-855mm. This gives us a minimal LOS of ~570mm rather than ~500mm on the left cheek. And we can use that to estimate the right side armor LOS. The right side of the turret have a shallower sweep but houses all the most important equipment of the tank so it makes sense to copy the frontal LOS rather than the 25-30 degree LOS to achieve a uniform protection from the front. Now if you put all that in to a 3d Program you will see that everything starts matching up really nice with photos, GPS housing, real dimensions and the ones we find in CIA documents and Army technical papers.

Scaling the array composition we of cause also have to take offset in the numbers we can find in official documents and the CIA drawings.
When you scale the armor drawings you find that they have similar amounts of steel LOS at the appropriate angles.
The Gun Shield has a 6" back plate(part of the rotor) a ~1,3" LOS plate(probably not steel), 12,5" deep Special Armor(SA) array and a 1,6" plate angled at 33 degree obliquity giving 2" LOS
The Hull front has a 5,8 LOS backplate(110mm plate) ~12" deep SA array and a 1,3" plate at 49 degree obliquity giving ~1,65" LOS.
Hull side is pretty similar despite missing SA.

We know that the hull front could defeat the XM579E4 APFSDS(at 1470 m/s) but not the XM774 APFSDS 
XM579E4 could penetrate 161mm RHA at 60 degree obliquity (322mm LOS)
XM774 could penetrate 189mm RHA at 60 degree obliquity (378mm LOS)

BTW (322+378)/2 = 350 , probably where the 350mm figure stems from.

And now we have to decide how to interpret the given information.
The Army tells us in  New York Times, march, 1978 that the Abrams can not be penetrated by its own round, which is capable of penetrating 15"(380mm, XM774) of armor.
CIA documents tells us that one version of the Abrams turret has 400mm-KE 750mm-CE protection
UK tells us 25 degree XM579E4 protection is principal
others say 30 degree 350mm protection.

How I read this is that the steel LOS of Gunshield with SA LOS of hull is likely how the front cheeks are armored. However it might just be similar to the hull in composition.

Turret side armor over the crew compartment looks different but is really just the hull armor scaled to 65 degree obliquity. Instead of the 3 SA tri plates being angled relative to the outer plate they are lying parallelly to the plate.  The rear plate being ~2,49" thick LOS at 25 degree angular is ~150mm(~5,9") with the outer plate being 19mm that is ~45mm(1,8") LOS.
My estimation of side LOS is 400mm rather than Gaijin's 381mm, I think they missed the fact that the roof plate is recessed down into the interior side plate.

Turret bustle has thicker LOS of about 441mm and while it has probably bad KE protection head on it will likely provide better protection than the front armor at 25-30 degrees angular.

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 Maybe you should read something before posting ? especially part about "M1(M1 105mm)" ?

 

my estimations ONLY for M1, why you trying to show me M1A1 and M1A2 ? 

 

11 hours ago, STGN said:

Where to start... I am guessing

try to start with arguments, i'm really not interested in reading wall of text without any arguments, with all respect.

 

for my estimates i used WT outer plates thicknesses that they posted in developer diary, because they used USG, so all these measures are correct.

 

for whole frontal part estimate i used photogrammetry of whole M1 and some measures that get from modelers(armorama site etc), i also used M1 dimensional scheme, and all that measures are coincided

 

5mNLYbeluzQ.jpg

qcIBHKPODAs.jpg

 

oBpYhO1j0Lc.jpg

 

MLDotlxQIpI.jpg

 

as for 4inch frontal plates is often quoted in US sources, so at the moment i use that value, maybe you can give us USG of internal plate ?

or on what source all your claims is based ?

 

here is scheme showing production stages of M1 turret, so it's have same spacers as hull front, and i think overall same structure, and it corresponds with CIA scheme + i'm not tried to get "REAL SIKRIT SPECIAL ARMOR SCHEME!11" only thickness of frontal part.

 

as for your "armour values" investigation, BRL1 during trials was penetrated by XM774(26mm diam core) from 3km, and it's claimed that BRL1 target was 10% tougher than real M1, but i'm not interested in any armour calculations at the moment.

 

So, you registered here for reasonable discussion with proofs, or just to chat about that "in some game everything is not right! I think so! but I'm not sure ..." ?

 

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Here are also seems to be another view of an Abrams turret shell CAD model in the lower right corner of the image:

 

tzniIonhBLQ

It seems that certain Abrams tank test rigs such as the M1 Thumper used the original M1 turret as a base instead of creating a new turret from scratch.

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11 hours ago, STGN said:

Scaling the array composition we of cause also have to take offset in the numbers we can find in official documents and the CIA drawings.
When you scale the armor drawings you find that they have similar amounts of steel LOS at the appropriate angles.

 

The drawings included in the official CIA document are not for scale. The confirmed measurements do not match with each other and depending on what value one chooses as references, differences in scaled/estimated armor thickness in excess of 100 mm are possible.

 

11 hours ago, STGN said:

The Army tells us in  New York Times, march, 1978 that the Abrams can not be penetrated by its own round, which is capable of penetrating 15"(380mm, XM774) of armor.

 

The XM774 wasn't adopted as in 1978, so it cannot be stated as a fact that the New York Times article refers to it. XM774's adoption was delayed to FY81 due to production issues.

 

Based on the Special Armor IFV studies of the Infantry FIghting Vehicle Task Force (from which you apparently took the penetration values for the XM579E4 and the XM774), the XM1 Abrams was not designed to withstand the XM774 APFSDS. According to the vulnerability analysis done by the BRL, the concepts 1, 4 and 5 - all of which were designed with protection equivalent to the XM1 tank - were protected against the 115 mm APFSDS (WA) only, which was simulated using the XM579E4 APFSDS. The hull and turret front could be defeated by the 115 mm APFSDS (DU) fired from one kilometer distance (no shorter distance was used for this analysis).

 

To increase protection against the 115 mm APFSDS (DU) as simulated by the XM774 APFSDS along a frontal 50° arc, new armor arrays were designed based on the same technology as used on the XM1 tank. These armor arrays were 6 tons (concept 1) or 5.3 tons (concepts 4 and 5) heavier than the original XM1 level armor array.

 

11 hours ago, STGN said:

CIA documents tells us that one version of the Abrams turret has 400mm-KE 750mm-CE protection

 

These steel equivalent protection values are very much irrelevant, as they are highly dependent on round. We know from the hearings regarding the adoption of the 120 mm smoothbore gun in front of a subcommittee of the US Congress, that the BRL-2 special armor target provides more protection than the XM1 tank's armor, which was described as roughly equivalent to the BRL-1 special armor target. The XM774 was tested against BRL-1 and the results weren't bad.

 

We also know that the 120 mm growth potential rounds from the FRG and the UK - i.e. prototype versions of the DM23 and L23A1 APFSDS modified for the US - managed to defeat BRL-2 at the tested ranges. As the DM23 has only 400 mm penetration into steel at 200 m based on the German measuring methodology according to declassified British documents, this make the CIA armor values rather questionable.

 

11 hours ago, STGN said:

UK tells us 25 degree XM579E4 protection is principal

 

The British declassified documents, German declassified documents, the SAIFV study and the Swedish leaks confirm that the US had a requirement for full armor protection only along a 50° frontal arc.

 

On 9/13/2020 at 5:17 PM, sksslrkalqek said:

There seems to be a difference between Bustle and Crew Area's Side Armor in Abrams Turret.

 

No offense, but this is well known and has been posted here already months ago.

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9 hours ago, Wiedzmin said:

 

 Maybe you should read something before posting ? especially part about "M1(M1 105mm)" ?

 

my estimations ONLY for M1, why you trying to show me M1A1 and M1A2 ? 

 

try to start with arguments, i'm really not interested in reading wall of text without any arguments, with all respect.

 

for my estimates i used WT outer plates thicknesses that they posted in developer diary, because they used USG, so all these measures are correct.

 

for whole frontal part estimate i used photogrammetry of whole M1 and some measures that get from modelers(armorama site etc), i also used M1 dimensional scheme, and all that measures are coincided

 

5mNLYbeluzQ.jpg

qcIBHKPODAs.jpg

 

oBpYhO1j0Lc.jpg

 

MLDotlxQIpI.jpg

 

as for 4inch frontal plates is often quoted in US sources, so at the moment i use that value, maybe you can give us USG of internal plate ?

or on what source all your claims is based ?

 

here is scheme showing production stages of M1 turret, so it's have same spacers as hull front, and i think overall same structure, and it corresponds with CIA scheme + i'm not tried to get "REAL SIKRIT SPECIAL ARMOR SCHEME!11" only thickness of frontal part.

 

as for your "armour values" investigation, BRL1 during trials was penetrated by XM774(26mm diam core) from 3km, and it's claimed that BRL1 target was 10% tougher than real M1, but i'm not interested in any armour calculations at the moment.

 

So, you registered here for reasonable discussion with proofs, or just to chat about that "in some game everything is not right! I think so! but I'm not sure ..." ?

 

Maybe you should read what I wrote before you get defensive.

The internal structure of all productions Abrams models is the same, that is why you can turn a M1 into a M1A2C using the same original turret, you just replace necessary external parts. That is why I posted the image of the internal structure from US army documents.

 

I was starting with arguments if you bothered to read them. My guess was how to approach it which I have to admit failed.

 

First argument: Gaijins 19,5" figure is wrong because it measures from the wrong point.

 

Second argument: The frontal turret armor of the Abrams is adjustable, it is not like the front hull armor with a solid monolithic plate of armor in the back, rather it is more like the bustle armor, you bolt armor plates to a "thin" back plate.

 

Third argument: The frontal hull armor has a LOS of 650mm. You can get that from SAIFV, UK gov docs, from CIA drawings if you scale them to the tanks dimensions.

 

Fourth argument: Protection level of front hull was the same for the Turret. Therefore using M1 armor technology we need 650mm LOS on turret to achive same protection at the apropriate angle, 25 or 30 degrees angular

 

Fifth argument: Giving 650mm LOS to 25-30 angular on left side gives ~800mm frontal LOS, applying that ~800mm LOS to the right side lines up with the rest of the turret structure, GPS well etc.

 

 

If your didn't get it the reason I mentioned the protection level was to emphasize that LOS is not just random but integral to the armor protection level.

 

 

Then I gave you my measurements of the CIA drawings of the SA. Which is base on the same images you posted though in a bit better resolution, here is a taste:

c8vd7z.jpg

And that is the source of the estimates. And why I found that steel LOS was very similar on parts that had same armor specifications.

 

I have also made 3d models though its many years ago now:

B8Y9v7.jpg

 

That "productions stages" drawing looks very much like its from a model kit, not actual turret. Just look at the rotor, that is not how the M1 rotor housing looks.

 

But talking about sources:

Maybe I am out of the loop but which source talks about 4" armor?

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7 hours ago, SH_MM said:

 

The drawings included in the official CIA document are not for scale. The confirmed measurements do not match with each other and depending on what value one chooses as references, differences in scaled/estimated armor thickness in excess of 100 mm are possible.

 

 

The XM774 wasn't adopted as in 1978, so it cannot be stated as a fact that the New York Times article refers to it. XM774's adoption was delayed to FY81 due to production issues.

 

Based on the Special Armor IFV studies of the Infantry FIghting Vehicle Task Force (from which you apparently took the penetration values for the XM579E4 and the XM774), the XM1 Abrams was not designed to withstand the XM774 APFSDS. According to the vulnerability analysis done by the BRL, the concepts 1, 4 and 5 - all of which were designed with protection equivalent to the XM1 tank - were protected against the 115 mm APFSDS (WA) only, which was simulated using the XM579E4 APFSDS. The hull and turret front could be defeated by the 115 mm APFSDS (DU) fired from one kilometer distance (no shorter distance was used for this analysis).

 

To increase protection against the 115 mm APFSDS (DU) as simulated by the XM774 APFSDS along a frontal 50° arc, new armor arrays were designed based on the same technology as used on the XM1 tank. These armor arrays were 6 tons (concept 1) or 5.3 tons (concepts 4 and 5) heavier than the original XM1 level armor array.

 

 

These steel equivalent protection values are very much irrelevant, as they are highly dependent on round. We know from the hearings regarding the adoption of the 120 mm smoothbore gun in front of a subcommittee of the US Congress, that the BRL-2 special armor target provides more protection than the XM1 tank's armor, which was described as roughly equivalent to the BRL-1 special armor target. The XM774 was tested against BRL-1 and the results weren't bad.

 

We also know that the 120 mm growth potential rounds from the FRG and the UK - i.e. prototype versions of the DM23 and L23A1 APFSDS modified for the US - managed to defeat BRL-2 at the tested ranges. As the DM23 has only 400 mm penetration into steel at 200 m based on the German measuring methodology according to declassified British documents, this make the CIA armor values rather questionable.

 

 

The British declassified documents, German declassified documents, the SAIFV study and the Swedish leaks confirm that the US had a requirement for full armor protection only along a 50° frontal arc.

 

 

No offense, but this is well known and has been posted here already months ago.

1. I agree that the images in their original state are a bit skewed. However when you apply the correct external dimension and internal(center of gun rotor) you get the same values that Gaijin measured on the outside of plate thickness. they also correspond to other measurements on the outside of the tank like distance between front of front plate and weld line of the hull array. Plus you get the same LOS when you measure on SAIFV drawings and the British computer drawings. So I think they are actually pretty accurate.

2. I have to clarify I think the front turret can withstand the xm774 not the hull. You are quit right I have read the report many times.

3. Maybe the steel equivalent values are "irrelevant" however my point was that when you are designing after a specific threat once you have an armor that can defeat it then you can just apply it, and when you calculate the numbers you find that the steel LOS is similar for arears that is suppose to defeat the same threat.

4. The 400mm number from CIA seems to be obviously based on the XM774 also there is a difference in how the Germans measure armor and how the Americans measure armor. I don't recall reading the DM23 400mm claim at what angle was the steel, it penetrated?

5. You are quit right about all these documents, however its the turret front we are interested in here not overall protection.

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1 hour ago, STGN said:

First argument: Gaijins 19,5" figure is wrong because it measures from the wrong point.

i use only GJ thickness of external plates, all other i get from photogrammetry and measures, what else you don't understand ?

 

1 hour ago, STGN said:

Second argument: The frontal turret armor of the Abrams is adjustable, it is not like the front hull armor with a solid monolithic plate of armor in the back, rather it is more like the bustle armor, you bolt armor plates to a "thin" back plate.

source ?

1 hour ago, STGN said:

from CIA drawings if you scale them to the tanks dimensions

scaling of schemes... good luck

 

1 hour ago, STGN said:

If your didn't get it the reason I mentioned the protection leve

i'm not interested in protection levels

 

1 hour ago, STGN said:

Which is base on the same images you posted though in a bit better resolution, here is a taste:

and ? i have high-res on that pics it's not secret, and they match photogrammetry 

 

1 hour ago, STGN said:

That "productions stages" drawing looks very much like its from a model kit, not actual turret

good luck to you with your hollywar :)

 

 

p.s and please do not confuse the words "argument" and "personal opinion", because all your "arguments" is just your words, without any sources or proves 

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33 minutes ago, Wiedzmin said:

i use only GJ thickness of external plates, all other i get from photogrammetry and measures, what else you don't understand ?

 

source ?

scaling of schemes... good luck

 

i'm not interested in protection levels

 

and ? i have high-res on that pics it's not secret, and they match photogrammetry 

 

good luck to you with your hollywar :)

 

 

p.s and please do not confuse the words "argument" and "personal opinion", because all your "arguments" is just your words, without any sources or proves 

1. Oh wow you got internal measurement from photogrammetry, you must be a genius. 

2. Can you see the images I posted or is there some magic spell called 105mm that completely changes the design of the turret, you do know that the turret was designed for the option to be upgraded, right?

3. Yeah we all know that the worst source for information is official drawings. But I look forward to your photogrammetry of the inside of the armor.

4. Yeah put your fingers in your ears and yell lalalalal, because there is no corrolation between armor dimensions and protection level I guess.

5. And? there you have the source which you have just confimed is in line with your photogrammetry.

 

6. Which holy war? You mean that I argue, that in order to achieve the desired protection level the armor has to be thicker than what you "guessed", so as I am arguing that the armor is less effective than what you want it to be, and I am waging a holy war?
 

7. You obviously don't know what an argument is, because you are the one just posting a picture putting on values with out having any evidence or logic behind it.

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1 hour ago, STGN said:

1. Oh wow you got internal measurement from photogrammetry, you must be a genius

is that geometry is hard for your understanding? i don't see any reason why photogrammetry of real tank + measures check + pics of ripped of M1A1 sides is doesn't give you a chance to check all "LOS" that you need(especially when you can check where the plate is, where the hatch is etc), or you just god of 3d models and can make it more accurate than real tank ?

 

i think remembered you, you was on defenceforumindia ? 

1WRWflmgQGE.jpg

is that your scheme ?

 

1 hour ago, STGN said:

Can you see the images I posted

same question 

 

1 hour ago, STGN said:

official drawings

have you ever seen any real factory blueprints lol ?

 

1 hour ago, STGN said:

But I look forward to your photogrammetry of the inside of the armor.

well, why don't you make your own ? to prove that everything is wrong ? 

 

1 hour ago, STGN said:

You mean that I argue

you trying to protect your believes, i'm not interested in that, if you want really discuss i'm interested, but all i see now, "all you data is from GJ!1" but i showed you that i used only external plates thicknesses, and you keeps put your fingers in your ears....

 

1 hour ago, STGN said:

because you are the one just posting a picture putting on values with out having any evidence or logic behind it.

oh funny thing, i though you was doing that, because i can't see any real arguments  

 

 

just to be clear, if you really want discuss "how we will get accurate LOS" ok go, i'm interested, if you keeps insists "oh all your pics a shit, because i think mine better" well, no go...

 

I am fully admit that I could be wrong in my estimates, but so far I've not seen any counter-evidence from you. Only "I believe that if ...", etc.  Please show your geometrically based figures, not some estimates like"theoretical if LFP los is 650mm, then turret 100% must be..." ?

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3 minutes ago, Wiedzmin said:

is that geometry is hard for your understanding? i don't see any reason why photogrammetry of real tank + measures check + pics of ripped of M1A1 sides is doesn't give you a chance to check all "LOS" that you need(especially when you can check where the plate is, where the hatch is etc), or you just god of 3d models and can make it more accurate than real tank ?

 

i think remembered you, you was on defenceforumindia ? 

1WRWflmgQGE.jpg

is that your scheme ?

 

same question 

 

have you ever seen any real factory blueprints lol ?

 

well, why don't you make your own ? to prove that everything is wrong ? 

 

you trying to protect your believes, i'm not interested in that, if you want really discuss i'm interested, but all i see now, "all you data is from GJ!1" but i showed you that i used only external plates thicknesses, and you keeps put your fingers in your ears....

 

oh funny thing, i though you was doing that, because i can't see any real arguments  

 

 

just to be clear, if you really want discuss "how we will get accurate LOS" ok go, i'm interested, if you keeps insists "oh all your pics a shit, because i think mine better" well, no go...

1. Oh great because you don't realize that you can actually test out an hypothesis about size and volume using 3d. Things have to fit together you know.

2.Great, yes. And yes I did make that, based on what I knew at the time. If you are going to be pointing out that it is not 100% right, then I already know that as I have updated my knowledge since then.

3. I did, what is the point here?

4. Yes I have.

5. I never said "everything is wrong" I said it is "mostly wrong", sure you got the outside right, however you put alot of numbers on the inside, we already know the outside of the tank, its the inside that is the interesting part.

6. Maybe you should be looking at the mirror to answer the question who is protecting their beliefs.

7. Right even as I went through all the logic of my argument you can't see anything.

8. I never said all your pics are shit. That is something you have chosen to read into it. I specifically criticized the composition and LOS of your drawing of the Abrams left side turret armor. 

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3 hours ago, STGN said:

1. I agree that the images in their original state are a bit skewed. However when you apply the correct external dimension and internal(center of gun rotor) you get the same values that Gaijin measured on the outside of plate thickness.

 

Negative. The drawings from the declassified CIA report cannot be corrected in order to provide accurate information. Even applying both values measured by Gaijin shows that they do not match. Adding a third value - such as the well documented and proven thickness of the upper glacis plate - only shows more conflicts with the other values... and that remains the case even after fixing the wrong orientation of document in the scanner and fixing distortion using software.

 

3 hours ago, STGN said:

2. I have to clarify I think the front turret can withstand the xm774 not the hull. You are quit right I have read the report many times.

[...]

4. The 400mm number from CIA seems to be obviously based on the XM774 also there is a difference in how the Germans measure armor and how the Americans measure armor. I don't recall reading the DM23 400mm claim at what angle was the steel, it penetrated?

 

And what exactly makes you think that the turret front of the M1 Abrams can withstand the XM774 APFSDS and that the armor value from the CIA document refers to the XM774 APFSDS? There is no source or reason for such claims. This seems to be rather your "feeling" than any logical claim.

 

First of all, the CIA document is very unspecific regarding the protection level - at what angle is the protection level achieved, what round is used as reference and why does it talk specifically about "one version of the M1 turret"? You seem to make assumptions regarding all these questions and then use these assumptions in the next step to claim that the M1 Abrams' turret could resist the XM774 APFSDS. I cannot agree with that, as you are ignoring a number of other facts and there is no basis for coming to your conclusion given the lack of supportive arguments.

 

In the previous and in the following paragraphs of the very same CIA document, US estimates for the performance of tungsten-carbide cored/tungsten alloy APFSDS rounds of Soviet origin are mentioned. It would be a very stupid way of displaying data - using values for WC/WA at all places but one - specifically given that the US was very aware of the higher efficiency of monobloc rounds against multi-layered targets since at least 1975/76 (more on that later).

 

The statement regarding "one version of the M1 turret" is also interesting, given that the work on the M1E1 already had started at the time! The CIA - in a different document - attributed the M1A1 Abrams tank with 380 mm steel-equivalent protection against an unspecified APFSDS round...

 

 

There was no requirement for protection against the XM774 APFSDS and the 1976 ballistic tests conducted on the XM1 prototypes and the Leopard 2AV did not involve any XM774 APFSDS rounds. We know that according to the SAIFV vulnerability in 1978 the XM1 armor was not able to stop the XM774 APFSDS and that the performance of the XM774 round against BRL-1 (and at shorter ranges possibly also against BRL-2) - which was seen as comparable to the frontal armor fo the XM774 - was considered satisfactory by the US Army also in 1978. In 1978 also the FSED prototypes were delivered, which were basically identical to the later series version. You state that the turret front was likely better protected and hence could survive hits from the XM774 APFSDS projectile, but the British assessements of the XM1's armor suggest that the difference was nowhere as large as you suggest; i.e. the different parts of the tank were designed to withstand from 400 meter different distance (800 m instead of 1,200 m).

 

The US Army also noted in the 1978 hearings on the smoothbore gun, that the XM774 likely performs better than the 38 mm two-piece tungsten round (DM13 APFSDS prototype) fired in the tri-parite gun trials of 1976; while the initial 1976 trials did not include Chobham armor targets like BRL-1 and BRL-2, this belief was based on the (poor) performance of similar US designs (i.e. XM579 and later XM735, which was adopted as new designation for the later XM579 prototypes) against such targets. In other words: if the XM1's turret fornt was able to provide protection equivalent to 400 mm of steel armor against the XM774 APFSDS round, then it would provide significantly more protection against XM579/XM735 and DM13... weird that they only specified protection against the 105 mm XM579 round at 800 meters then, when it should rather be 0 meters distance.

 

If the XM774 would be better against BRL-1 (XM1 equivalent armor) than the German 120 mm APFSDS with 38 mm tungsten alloy cores, then the armor would be immune against the XM579/XM735 rounds. The 105 mm version of the DM13 APFSDS (with an identical penetrator with 38 mm tungsten alloy cores) could penetrate 165 mm steel armor sloped at 60° at 800 meters distance - but German steel made to the TL 2350-001 specification. This steel was found to be considerable better than RHA manufactured to US specs during the 1976 tri-partite gun trials. So this round is already superior to the XM579E4 APFSDS. The Leopard 2AV was required to stop the 105 mm APFSDS round with 38 mm tungsten cores from 200 meters distance and the 120 mm version from 1,500 meters distance. If the XM1's turret survived hits from the XM774 at point blanc range (as you essentially claim), then it also would be immune to 120 and 125 mm APFSDS from point blanc range until the mid-1980s. This is clearly not the case based on the requirements, specifications and the development of the M1E1/M1IP tanks.

 

Also in 1978 the UK believed that a monobloc DU APFSDS capable of penetrating 445 mm of steel armor at 1,000 meters would be sufficient to defeat the frontal turret armor of the M1 Abrams at distances in excess of 4,000 meters.

 

_______________________________________

 

If anything the 400 mm figure is a reference to the protection against APFSDS rounds with WC/early WA cors or a reference to the M1E1 tank's specifications. It also could be a mix both at the same time.

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      Appendix 1- armor calculation
      Appendix 2- operational requirements
       
      Good luck, and may Hubbard guide your way to enlightenment!

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