Main Battle Tanks and Armour Technology

[shuvo@y2k10]

Re: Arjun Main Battle Tank (MBT)

Sorry, but if you will stick with rifled gun, you loose two important opportunities, first is capability to test and purchase more types of ammunition. Second you loose on foreing markets because world wide, rifled guns are not used anymore, especially in 120mm calliber.

As for HESH, HESH is also considered as obsolete type of ammunition world wide. I explained so many times why due to it's working mechanism, it is very simple to make HESH ineffective even against structures like bunkers. It is also cheap to make so.

As for "Armata" MBT, it will use new type of 125mm smoothbore gun the 2A82, but designers will also provide capability to rearm for 152mm 2A83.

NATO have several developed and tested 140mm guns, the US XM291, German NKPz-140 and also their French, British and Swiss analogs. So it is possible to start manufacturing of them, but a bit longer would take to actually design new ammunition for them. Also allready existing MBT's would need adaptation for these guns, as ar as I know only Swiss gun and US XM291 were ok to be installed in existing turrets, however at leas Americans and Germans designed new turrets for M1 and Leopard 2 to better fit 140mm in to them, I also know a French concept drawing of improved Leclerc with 140mm.

What i said was as soon as army demands a smoothbore gun drdo can manufacture one and there are no technological barriers to that.Also the whole point of developing arjun mbt was to acheive self reliance in the field of tank production which includes ammunitions as well.Hence i don't think we would buy 120mm ammunition from global market and drdo would develop and manufacture next generation ke and heat rounds.However we will buy ammunitions for 125mm from russian/global market for t-72 and t-90 which are in service and also israeli apam rounds for anti personnel use.Yes hesh may have become ineffective against modern mbt's today but it is still a very good and cheap long range options against enemy bunkers and concrete structures and is a very suitable for the kind of urban warfare in iraq and afghanistan.As far as arrjun mk3 goes i think it needs a bigger gun(7-8m in length) of higher caliber like 140mm/152mm/155mm.this is because america and many european countries like germany,france swiitzerland etc have developed 140mm gun and russia has developed 152mm gun.this kind of gun can be even installed on current 3rd gen mbt turret's with slight or no modifications.hence india should invest in that.

 

[Damian]

Re: Arjun Main Battle Tank (MBT)

.Yes hesh may have become ineffective against modern mbt's today but it is still a very good and cheap long range options against enemy bunkers and concrete structures and is a very suitable for the kind of urban warfare in iraq and afghanistan.

Bukers and concrete structures can be very cheaply and simple make immune to HESH, a simple steel screen placed even 100mm from the main structure of such fortification makes it immune to HESH.

As for urban combat, you think why nobody wants conventional HE (this means also HESH) ammunition but wants programmable HE? Simply because detonating explosive charge on the outer surface of building is not considered as efficent any more. You need to penetrate building and detonate charge inside, not outside, to have higher efficency.

As far as arrjun mk3 goes i think it needs a bigger gun(7-8m in length) of higher caliber like 140mm/152mm/155mm.this is because america and many european countries like germany,france swiitzerland etc have developed 140mm gun and russia has developed 152mm gun.this kind of gun can be even installed on current 3rd gen mbt turret's with slight or no modifications.hence india should invest in that.

This is no that easy, believe me, if it would be we would allready see Challenger 2's, M1's, Leo2's and Leclerc's with 140mm smoothbores, and the problem was not the gun, the problem was tank itself, the general consensus was that if you want a bigger gun, in the end you need a new tank, and the best would be if such tank would have unmanned turret.

 

[militarysta]

Re: Arjun Main Battle Tank (MBT)

This is no that easy, believe me, if it would be we would allready see Challenger 2's, M1's, Leo2's and Leclerc's with 140mm smoothbores, and the problem was not the gun, the problem was tank itself, the general consensus was that if you want a bigger gun, in the end you need a new tank, and the best would be if such tank would have unmanned turret.

Propably the only western III gen. tank redy for 140mm is Leclerc. Leopard-2 need almoust new turret (very very deep rebuild now exist turret...) the same Abrams. Merkava is unkown. Only the Leclerc is redy (oversize gun mantled mask, FCS, gun drivers, place for bigger autoloader, esy modyfication to incarase turret bustle lenght ) for 140mm gun. But it's the result of developing Leclerc in end of the 1980s. when Soviet Future Tank-1 and 2 where suspected as very difficult enemy.

 

[Damian]

Re: Arjun Main Battle Tank (MBT)

Propably the only western III gen. tank redy for 140mm is Leclerc. Leopard-2 need almoust new turret (very very deep rebuild now exist turret...) the same Abrams. Merkava is unkown. Only the Leclerc is redy (oversize gun mantled mask, FCS, gun drivers, place for bigger autoloader, esy modyfication to incarase turret bustle lenght ) for 140mm gun. But it's the result of developing Leclerc in end of the 1980s. when Soviet Future Tank-1 and 2 where suspected as very difficult enemy.

You are wrong, M1A1/M1A2 did not had any nececity to have modified turret to have XM291 in 140mm variant installed, tank was tested with success in USA, there is photo and photo is a better argument than some concept drawing.

As far as I could dig it out, they were still capable to store approx 30 rounds inside turret bustle. However loading 140mm rounds would probably be a bit cumbersome for human loader, so most probably autoloader would need to be installed. But Americans have successfull autoloader designs for M1.

However the ammunition used in such tank would be probably different than for other modification, it would be a single piece ammunition without additional propelant charge thus slower and less capable.

 

[methos]

Re: Arjun Main Battle Tank (MBT)

XM291 is not a pure 140 mm gun. It also comes in a 120 mm version, which seems to be shown in your image. According to Rolf Hilmes not even the 120 mm could be fitted on the M1A2, which is the reason why the U.S. started to test mounting the Rh 120 L/55 on their tanks.

 

[Damian]

Re: Arjun Main Battle Tank (MBT)

XM291 is not a pure 140 mm gun. It also comes in a 120 mm version, which seems to be shown in your image. According to Rolf Hilmes not even the 120 mm could be fitted on the M1A2, which is the reason why the U.S. started to test mounting the Rh 120 L/55 on their tanks.

XM291 was a bicalliber weapon. And no, gun on image is 140mm. And no, Hilmes is wrong or did not understood the problem correctly. There were no problems with placing gun in turret, there was problem with stabilization, just like in case of Rh-120/L55, which was later solved by a simple solution, but in the end it was decided that new gun is not nececary for increasing firepower.

Here are some photos more.

As you can see, gun was installed in several different turrets, two old (M1 and M1A2) and two new ("Thumper" and CATTB). It also have clearly visible evolution process in case of size and shape of bore evacuator and thermal shroud.

140mm made by Swiss designers, also could be fit in standard Leopard 2A4 turret.

To install such gun in standard turret used by MBT in service today, the gun itself is not a problem and not the main reason for new turret, new turret is needed mainly due to size of ammunition and the need of autoloader. After all 140mm is only 20mm bigger than 120mm when it comes to diameter.

Of course we can consider a nececy modifications in gun mount, stabilization, servomechanisms to use such gun in regular service.

So definetely our Indian friends can consider NATO experiences and use their as a guide if they will see fisible to rearm in to 140mm calliber, or bigger.

 

[methos]

Re: Arjun Main Battle Tank (MBT)

No. Hilmes completely understood the problem. It was not "the stabilization does not work as required" - else they simply would have changed that. The problem was much more complex.
Neither the 140 mm nor the 120 mm version of the XM291 were fired from an M1A1/2 turret - the Rh 120 L55 was the only tank gun not fired from static mounts only, but also from real production turrets.

And were can be seen that the gun on the pictured tank is a 140 mm one? Rumors? It looks much different from actual 140 mm guns.

Swiss 140 mm ammunition is smaller and the gun was designed to be a retrofit option - just like the Compact Tank Gun. The XM291 was not designed for the M1A1/M1A2 turret. In the same way you could claim that the NPzK 140 is compatible with the Leopard 2, just because some prototype (with extra weights) was used for static firing trials.

 

[Damian]

Re: Arjun Main Battle Tank (MBT)

No. Hilmes completely understood the problem. It was not "the stabilization does not work as required" - else they simply would have changed that. The problem was much more complex.
Neither the 140 mm nor the 120 mm version of the XM291 were fired from an M1A1/2 turret - the Rh 120 L55 was the only tank gun not fired from static mounts only, but also from real production turrets.

And were can be seen that the gun on the pictured tank is a 140 mm one? Rumors? It looks much different from actual 140 mm guns.

Swiss 140 mm ammunition is smaller and the gun was designed to be a retrofit option - just like the Compact Tank Gun. The XM291 was not designed for the M1A1/M1A2 turret. In the same way you could claim that the NPzK 140 is compatible with the Leopard 2, just because some prototype (with extra weights) was used for static firing trials.

Well we have your and Hilmes claims against photos of the real things... I believe more real things.

Here you have XM291 on display, it is not much bigger than M256 or XM360E1.

Here is L55 used by Turkish as Altay armament, breach assembly is more or less the same size as in case of XM291.

I suspect that Americans also considered XM291 as a direct replacement option for M256, they also wanted a bigger more capable ammunition and autoloader, this is why they were experimenting with these new turret designs, to have adequate ammunition quantity stored inside and autoloader + other benefits.

 

[methos]

Re: Arjun Main Battle Tank (MBT)

Well we have your and Hilmes claims against photos of the real things... I believe more real things.

We don't have any photo showing the 140 mm version installed on a M1 Abrams nor any proof that it is practical possible to mount such a gun in the M1A1/2 and to shoot without the recoil/gun screwing up the turret.

And where is the connection between a gun displayed and the tank exactly? There were two different calibers - just because a gun not installed in the turret might be 140 mm, the gun of the tank pictured does not have to be the 140 mm version. In fact there are U.S. documents (like DYNAMICALLY TUNED SHROUD FOR ATTENUATING GUN BARREL VIBRATION) which mention that the 120 mm version of the XM291 was mounted in a M1A2 and driven around on the Aberdeen Proving Ground. No shots were fired because the robustness of the system was questioned.

The pictures of the CATTB and the M1 provided in post #4522 actually show the gun without the dynamically tuned shroud installed on the XM291 during development in order to reduce vibrations.

 

[Damian]

Re: Arjun Main Battle Tank (MBT)

As far as I can tell from photos, gun on "Thumper" technology demonstrator is bigger in diameter than 120mm guns, and it is the same gun as on that M1A2.

So for now we can agree that we disagree.

BTW not all documents are declassified, perhaps in future more will be known.

 

[militarysta]

Re: Arjun Main Battle Tank (MBT)

there was problem with stabilization, just like in case of Rh-120/L55,

Jesus (or rather flying spagetti monster) Damian! - stop repeting those bullshit from BTVT and other pages from Russia. There was no 'problem with stabilization" in case Rh120 L-55. There was no problem whit E-WNA - it was redy and tested before L-55 was redy. The problem was in the gun not in stabilisation! Germans find some technology problems during making gun whit longer then L-52 -and those problem have nothing common whit stabilisation. Rest on PM if You are interested.

 

[Damian]

Re: Arjun Main Battle Tank (MBT)

Jesus (or rather flying spagetti monster) Damian! - stop repeting those bullshit from BTVT and other pages from Russia. There was no 'problem with stabilization" in case Rh120 L-55. There was no problem whit E-WNA - it was redy and tested before L-55 was redy. The problem was in the gun not in stabilisation! Germans find some technology problems during making gun whit longer then L-52 -and those problem have nothing common whit stabilisation. Rest on PM if You are interested.

I was talking about problems with stabilization in M1 series when 120mm smoothbore gun was installed with barrel longer than currently used L44.

Please read carefully about what we are talking here.

Of course these problems were not the problems you can't solve, but Americans decided to stick with 120mm guns with barrels shorter than L50, at least officialy as the lenght of new XM360E1 is not 100% certain.

 

[militarysta]

Re: Arjun Main Battle Tank (MBT)

You are wrong, M1A1/M1A2 did not had any nececity to have modified turret to have XM291 in 140mm variant installed, tank was tested with success in USA, there is photo and photo is a better argument than some concept drawing.

Oh c'mon - so this photo prooof that Gemrnas haven't problem whit fit 140mm NPzK in leo-2 turret?

??
You can fit almoust any gun in turret and shoot form fixed position. The problem is whit autoloader, amunition, stabilisation during moving, etc. And making whole working "system" - gun+autoloader+amunition+FCS+stabilisation.
And in Hilmes there is very clerly part about Abrams and longer then L-44 gun -ressume:
1. development of the 120 mm smoothbore gun XM 291 with elongated barrel was so far advanced, that at the end of 1996 trial installations on the M1 MBT could be done. These apparently weren't very successful, so that the conversion programme (comment: meant are the trials) was stopped in 1998.
2. GDLS contacted the company Rheinmetall (Unterluess); to test the system compatability of the new German 120 mm smoothbore gun L/55 with the M1 in order of a model conversion ( comment: meant is to replace the gun on serial tanks also and not only on prototypes). In the year 2000 five barrels 120 mm L/55 were purchased from the company Rheinmetall and fitted into the vehicles. After the installation of the weapon system in the vehicles a technical evaluation (system compatibility test with live ammunition) aswell as troop trials were done. Results of these tests were not officially published.
btw: many thanks for Methos for translate those part.

So as You see- even 120mm longer then L-44 M1 gun program was difficult not even mentioned about 140mm...

 

[militarysta]

Re: Arjun Main Battle Tank (MBT)

I was talking about problems with stabilization in M1 series when 120mm smoothbore gun was installed with barrel longer than currently used L44.

Please read carefully about what we are talking here.

Of course these problems were not the problems you can't solve, but Americans decided to stick with 120mm guns with barrels shorter than L50, at least officialy as the lenght of new XM360E1 is not 100% certain.

Oh sorry, lack of coffee today morning.

EDIT: and my point about uniqe Leclerc feture is that - only Char Leclerc have tested and redy to put whole system for 140mm gun. So gun + working and easly to placed in autoloader, FCS, stabilisation, etc. In other tanks -np Leopard-2 we can put 140mm NPzK and we have FCS, E-WNA (stabilisation), ammo, but very big problem was placed autoloader or even manuall rack whit propelent charge autoloader - in fact half of the turret must be rebuild. In M1 cases there is posibility to put 140mm gun in turret but we have no infos about rest of the program (ammo, autoloader, stabilisation etc) but we had infos about problem whit put L-55 in M1 turret. Propably solved in cooperation whit Rheinmettal.
So more or less -only Leclerc is almoust redy to 140mm gun.

 

[methos]

Re: Arjun Main Battle Tank (MBT)

I was talking about problems with stabilization in M1 series when 120mm smoothbore gun was installed with barrel longer than currently used L44.

Actually the solution for the stabilization issues was already in development and used on a M1A2 prototype fitted with the XM291 tank gun tested on Aberdeen Proving Ground in 2001. The gun was fitted with a Dynamically Tuned Shourd (DTS), which is a connection working as shock absorber from the thermal shroud to the bore evacuator. When fitted the DTS the RMS improved by 24% and 9% (vertically and horizontally ) compared to a conventional system. The DTS also is the reason why the gun barrel appears to be much thicker than that of a conventional 120 mm gun.
On the XM291 the connection was used in from of a coil spring, which however had some problems. First of all it wasn't very robust, which is the reason why not a single shot was fired from a XM291 fitted in the standard M1A1/A2 turret. Besides that the XM291 tank gun was much more experimental than most other gun systems, because it was actually developed as 140 mm gun with the 120 mm version being secondary. The quadrolateral 140 mm guns (cooperation between FRG, UK, USA and France) all used much more advanced technologies which were still in development. E.g. composite materials were used to a very large extend, a higer degree of autofrettage was required, etc. The XM291 with 120 mm gun weighed 3689 kg, while the Rh 120 L55 weighs 4160 kg.
By an assement from Rheinmetall, Royal Ordnance and GIAT the 140 mm gun wouldn't be ready for production prior 2007 in best case; most of the technologies were
also used in the 120 mm version of the XM291 - which means that the XM291 wasn't close of being fully developed in 2001, when it was tested on the M1.
The German Rh 120 L55 is much more a "dumb solution" when it comes to new composite materials, etc., but there development was much more focused on internal geometry.
The M256E1 (Rh 120 L55) trialed on the M1A1/A2 was also fitted with a DTS, but of a slightly different design (e.g. the leaf spring designs mentioned later).

At first the DTS was made using coild springs, but that wasn't robust enough to work. Then instead of the previous system, a stronger spring collar was used, which was abandoned afterwards because it could interfere with the muzzle reference system and was probably unreliable (at least the reliability was questioned).
Following this leaf springs were used and actually firing trials (static and also on the tanks) were scheduled, but the problems arose during the in-house testing: "The screws meant to preload the leaf springs did not ride smoothly on the surface of the tube and caused the spring to twist as it was loaded. Also, they tended to kick out and get stuck if the absorber was hit with enough mass to cause it to bottom.".
The third (fourth if you count the non-robust version) of the DTS used leaf springs, but no adjusting screws - instead a wedge ring was mounted on the the attachments for the standard thermal shroud. The file from which I took this information doesn't specify the problems with this design, because it was still in testing when the file was written. But apparently something didn't work, else the M256E1 or with a later DOI the XM291 would have been fielded on the M1.

PS: Could/should the moderators please move these post to the "Tank Guns and Ammunition" thread?

 

[Dazzler]

up armoured Al Zarrar....

 

[Dazzler]

we signed for this MRAP from China..

 

[Dazzler]

 

[militarysta]

Re: Arjun Main Battle Tank (MBT)

PS: Could/should the moderators please move these post to the "Tank Guns and Ammunition" thread?

.........................x2

 

[Damian]

Al Zarrar use a simple spaced armor on turret, effective against HESH and simpler, less capable shaped charges or EFP's, but that's all.