T-80 Tanks

Gollevainen said:

So you state that when the lenght of the various gun parts are roughly 45% longer, it means that the gun is the same 45 % better than the one its being compared? Wau...does this logic apply to other areas as well? If one guy is 170 cm of height and another guy is 200cm, is the latter 15 % of better man? Or if the latters pen....You get the point

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No, I don't mean that kind of camparing.

What I mean is that only common point btwn Chinese gun and Russian is the caliber, actually they're totally different guns. So I don't think estimate based on Russian shell has any credit.

Second, I note that the longer the barrel is, the more powerful the gun. Also Chinese gun has a bigger combustion chamber, which means bigger round. Russian chamber has length of 383mm, sounds tool small. It maybe due to the calculation method difference.

Actually 2A46M-1 total length(6678mm) - barrel length(6000mm) may be how chinese calculates the chamber length, but still 880mm is a very big one.

Gollevainen said:

Yeas listen to crobato as he made a valid point.
I personally wont take a stand which one is right, as I'm not so familiar with the math Zraver presented. but this I would like to say...

...don't you kinds dare to keep internet based source a some sort of mythical grail that negelents all reason and laws of physics. Zraver has made his assumptions based on the known facts and physical limits of them but you guys are just arguing with him becouse some article published in some magazine indicates say that the chinese gun is so superior that the Zravers math just isen't right becouse it makes the gun being less miracleous. Comon, ever heard about objectivity?

The 125 mm gun in chinese tanks is derivation of the russian gun. There's no doupt about that. Its said so by the designers of that gun and us who have actually seen the russian gun alive have told (in the threads in the past when this issue raised last time) you that the chinese gun's critical parts (Breech mainly) are identical to the russian gun. So thus it gives Zraver every right to assume that the ammunition used is dictaded by the limitations of the gun which are somethat similar to the russian gun.

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From what I know there isn't just one 125mm gun but two. The one used on the ZTZ-99 is longer than the one used on the ZTZ-96, aka T-96 aka T-88C.

We cannot say we have seen the Chinese 125mm gun if we don't know exactly from which tank it came from.

Still, for the purpose of field logistics, it is not unreasonable that the two guns may share similar parts and would have to be using the same ammunition.

I think by now, nobody can dispute that Chinese 99 tank gun has big difference from the Russian 2A46 gun. Let's look at the 99 tank shell.

From this famous 99 tank shell photo, I measure and calculate the shell length, using a little math. I calibrate the length by 2 ways, assuming the soldier height is 1.70m, or comparing with the shell diameter(125mm), since that looks quite even. Both gives the result about 70cm, with the adjustment of that shell is not parallel to the screen exactly.


Considering the following 125mm APFSDS structure, if the shell length is ~70cm, then its projectile is close to 70cm, say ~65cm quite reasonable.
http://www.sinodefenceforum.com/attachment.php?attachmentid=1176&stc=1&d=1173924184

This is way much bigger than any Russian round, Russian 3VBM13/3BM32/33 has a projectile of only 47cm with 560mm RHA @ 1700m/s.


So clearly Chinese shell has nothing to do with Russian shells. The total length of 99 tank gun shell+combustion case is about 110cm, no wonder it has a big combustion chamber, make sense. And it's not exaggerate to say 99 tank gun has gain of 45% in power, considering its bigger projectile(65cm vs 47cm), bigger speed(1780m/s vs 1700m/s).

The bottom line, you can't compare Chinese shell with Russian ones, doesn't make sense.

Imagine the upgrade market for T-55/Type 59's rearmed with a new super D-10T made from this super metal and rounds made form unobtainium propelled by this revoultionary propellant. Artilerry systems, loght cannon, civillian applications ect. Yet depsite the claims of the ZTZ-99 Chinese chemistry and metallurgy still lag behind the west in almost all criticla areas. China still can't make a decent high by pass turbofan as an example of chinese metlauurgy.

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Excuse me, but you seem oblivious that the Chinese do have the 120mm gun (licensed from Oerlikon), and they have mounted them on their Type 89 SPGs. They also have the 120mm gun mounted on the T-55/59 as an upgrade for the older tanks.

So you can be pretty confident they know the ballistic qualities of the NATO 120mm.

Finally, the Chinese have mastered creating a decent high bypass turbofan. The J-11B using their indigenous engines have passed certification and prototype testing, and is now in serial production stage entering IOC into training regiments.

crobato said:

Excuse me, but you seem oblivious that the Chinese do have the 120mm gun (licensed from Oerlikon), and they have mounted them on their Type 89 SPGs. They also have the 120mm gun mounted on the T-55/59 as an upgrade for the older tanks.

So you can be pretty confident they know the ballistic qualities of the NATO 120mm.

Finally, the Chinese have mastered creating a decent high bypass turbofan. The J-11B using their indigenous engines have passed certification and prototype testing, and is now in serial production stage entering IOC into training regiments.

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Then why have two logistical trains for ammunition? Doesn't make sense, and would a nightmare logistically. If I were the Chinese in this case, I would just stick with the NATO 120mm due to the superior and proven firepower provided by the system.

Pointblank said:

Then why have two logistical trains for ammunition? Doesn't make sense, and would a nightmare logistically. If I were the Chinese in this case, I would just stick with the NATO 120mm due to the superior and proven firepower provided by the system.

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It's only limited trail for evaluation purpose.

One problem for 120, Chinese don't like that one-piece-shell autoloader, too complicated they think.

fishhead said:

Russian 2A46M1 spec, big difference

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barrel length: 6,000mm vs 6,412mm(99)
Recoil length: 260-300mm max 310mm vs 280-320mm, max 330mm (99)
Chamber length: 383mm(???) vs 880mm (99)

.

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I think I have a theory of how exactly it is done.

The key is large chamber size -- the increase
in chamber size is almost exactly L48 barrel + chamber size increase (500mm = 4*L) => 52L.

Why the increase? Because 2 propellant modules are used instead of 1. Note this allow the use of the T-72 type autoloader without modification.

Since the velocity is already near the limit, to keep the velocity more less the same, the penetrator has to be heavier -- this *may* means the L/D ratio has to be reduced or autoloader modified to accept longer length.
After all, it's easier to make thicker penetrator than a
thinner penetrator which is tough enough for the purpose.

ZTZ-99 actually comes with 2 versions of autoloader, one is T-72 based that went into the tank in 1999, there is another version designed from the scratch entering service 2 years later. All the spec disclosed today is the T-72 based autoloader, like 8 sec load time. Chinese didn't say any feature about the new autoloader.

Also the total weight of 99 gun goes up to >4 tons, almost same as L55 gun, compared with 2A46M1's 2.5 ton, up quite a bit.

I have a question, why are we using conservation of energy to calculate the depth of penatration. I am sure the sabot is not going to make a perfect elastic collision with the armor, ie energy will be lost to deform the tank instead of conserved. So shouldn't using momentun as the base of calculation makes more sense. You are getting less error from calculation not only because momentun by definition is how hard it is to stop a moving object, the formula will naturally yield less error.

Or is there some deep logic behind the KE that I completely missed.

optionsss said:

I have a question, why are we using conservation of energy to calculate the depth of penatration. I am sure the sabot is not going to make a perfect elastic collision with the armor, ie energy will be lost to deform the tank instead of conserved. So shouldn't using momentun as the base of calculation makes more sense. You are getting less error from calculation not only because momentun by definition is how hard it is to stop a moving object, the formula will naturally yield less error.

Or is there some deep logic behind the KE that I completely missed.

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Penetrating is deforming. The thing that counts is therefore kinetic energy. (kinetic energy pr. cm^2 is more accurate)

An easy example:
3 kilo coconut moving at 1m/s: p=m*V= 3*1=3 Ke=1,5
3 gram bullet moving at 1000m/s: p=m*v= 0,003*1000=3 Ke=1500

These two have the same momentum, but I think you know which penetrates most armour. (and, yes i know the surface aerea is different, just a silly example)


When it comes to constructing tank guns, it`s basically physics and metallurgy that are the limiting factors. That the chinese somehow should have managed to get superior performance with a shorter penetrator is not plausible.