Arjun Main Battle Tank (MBT)

[sayareakd]

guys be civilized........ dont ruin this thread

 

[Kunal Biswas]

Arjun MK-1 Details >>

 

[Dazzler]

Arjun MK-1 Details >>

some ammunition stored in the hull? interesting

 

[The Last Stand]

Pretty-much self explanatory.

Worrying that there are large weakspots, especially the gun mantlet.

Lower front hull hull shouldn't be a weakspot, but it is possible if we tried old Soviet protection philosophy.

 

[sayareakd]

some ammunition stored in the hull? interesting

it is their in Leopard 2.

 

[Dejawolf]

some ammunition stored in the hull? interesting

there's only 1 tank in the world without an unprotected hull ammunition store, which is the M1 abrams. every other tank in the world has one however.
on the Arjun, the ammunition is stored behind a fuel tank in the hull, which provides some additional protection.
if the indians followed Soviet design philosophy, front glacis of the tank should have about equal protection to the front turret (minus weakspots)
so unless you have ammunition that can penetrate the turret, you won't be able to penetrate the hull.

 

[ersakthivel]

The Mk2 prototype is 67.5 tonnes with a mine trawl. The plan is to bring it down to 62.5 tonnes before production starts.

Anyway, the program is moot in line of what the Army needs and that's already been established with the start of the FMBT program.

The future will be a 50 tonne FMBT with crew in the hull and most probably an unmanned turret.

So, no. We cannot afford a tank that weighs more than 50 tonnes financially as well as operationally, especially not in the numbers we require.

there are no FMBTs with 50 ton load if IA wants it to be 4 men crew with ammo safe storage.

Already DGMF has clarified that Arjun future versions will be the FMBT.

IF this 50 to weight limit is imposed IA can only fight the army of Srilanka .

That's why IA has already started standardizing itself on 70 ton sarvantra bridge layers for future.

http://defence-news.blogspot.in/2013/07/strike-force-would-allow-india-two.html

According to the article above most of Tibetain rivers are 20 to 140 meters in width in most places.

So with the recent light weight single span bridge that can bridge the gap of more than 120 meters for 70 ton tanks developed by DRDO, there is no bar on any area for Arjun deployment,

Especially as the border infra is built according to the future needs of IA in himalayan region

 

[Dejawolf]

Pretty-much self explanatory.

Worrying that there are large weakspots, especially the gun mantlet.

Lower front hull hull shouldn't be a weakspot, but it is possible if we tried old Soviet protection philosophy.

some measures of hull based on factory drawings.

front hull has a LOS thickness of 55cm on the glacis, and 20cm on the lower glacis. behind the armour, there's a fairly large fuel tank, which provides additional resistance from incoming rounds. as long as the tank is full it will provide some fairly substantial protection
in the order of 175mm vs KE and 643mm HEAT at it's thickest portion, and at least 70mm KE and 250mm HEAT on average.

 

[The Last Stand]

some measures of hull based on factory drawings.

front hull has a LOS thickness of 55cm on the glacis, and 20cm on the lower glacis. behind the armour, there's a fairly large fuel tank, which provides additional resistance from incoming rounds. as long as the tank is full it will provide some fairly substantial protection
in the order of 175mm vs KE and 643mm HEAT at it's thickest portion, and at least 70mm KE and 250mm HEAT on average.

What is the angle and how much will the protection actually be on the hull? You could use those Leo 2 armour composition values you used back then.

 

[Dejawolf]

What is the angle and how much will the protection actually be on the hull? You could use those Leo 2 armour composition values you used back then.

angle for upper front hull is 75 degrees, for lower hull 60 degrees. keep in mind the thickness is LOS, actual thickness is about 140mm for upper front, and 100mm for lower front.

for the older estimates, i overestimated the thickness of the front glacis by about 50mm, and the angle was 3 degrees too steep.

upper front vs KE: SHS(45+40)*1.25 + Kanchan(55*0.92) = 156mm or 602mm LOS
vs HEAT SHS(45+40)*1.25 + Kanchan(55*1.4) = 156mm = 183mm or 707mm LOS

adding the fuel and you get about 781mm vs KE at the thickest, about 670mm average, with 602mm at the spots on the upper front not protected by fuel.
HEAT values varies between 1350mm (at the very tip) with an average of about 950mm.

for the lower hull, i'll just assume all steel since it's only 100mm thick, so 125mm@60 = 250mm.
adding the protection from fuel you get a value of 425-320mm vs KE.

i'd assume the Arjun drains the front fuel tank last, to keep the front hull protected, wth the drums being emptied first, followed by the fuel on the skirts, and finally the front fuel tank.

 

[Kunal Biswas]

Back in expo in 2012, I asked the same question to the engg there..

He told me this, But also told me that there is Kanchan at frontal chassis after that there is diesel fuel..

 

[The Last Stand]

Back in expo in 2012, I asked the same question to the engg there..

He told me this, But also told me that there is Kanchan at frontal chassis after that there is diesel fuel..

Which question? Protection of the hull?

Is placing armour after the fuel tanks possible? The schematic image above shows little space after the fuel tank.

 

[The Last Stand]

upper front vs KE: SHS(45+40)*1.25 + Kanchan(55*0.92) = 156mm or 602mm LOS
vs HEAT SHS(45+40)*1.25 + Kanchan(55*1.4) = 156mm = 183mm or 707mm LOS

adding the fuel and you get about 781mm vs KE at the thickest, about 670mm average, with 602mm at the spots on the upper front not protected by fuel.
HEAT values varies between 1350mm (at the very tip) with an average of about 950mm.

for the lower hull, i'll just assume all steel since it's only 100mm thick, so 125mm@60 = 250mm.
adding the protection from fuel you get a value of 425-320mm vs KE.

i'd assume the Arjun drains the front fuel tank last, to keep the front hull protected, wth the drums being emptied first, followed by the fuel on the skirts, and finally the front fuel tank.

Are these sufficient protection values?

 

[Kunal Biswas]

Interestingly, all these flaws were discussed at this thread before 2012 expo ..

And personally i was concern about flaws specially

1. large mantel.
2. FCS location.
3. Fuel tank at frontal chassis.

Its quite satisfying to know from the mouth of the engg from Arjun Program, The following answers =======>>

1. Its large mantel was requirement and something with IA tactics in thar desert specially engaging enemy at higher depression from above sand dunes..

2. He said Yes, there is no composite Armour behind FCS but metallurgy of plates are thicker composition and harder..
3. Yes, there is composite Armour in hull before the fuel tanks, Fuel used is diesel ..

========================

I also found that Arjun and tank ex dont use similar Kanchan armors, EX used a different form of Kanchan Armour so does T-90S and T-72M1, But material used can be same in all ..

Kanchan is available in many forms, there are designation for them which is not public..

Which question? Protection of the hull?

Is placing armour after the fuel tanks possible? The schematic image above shows little space after the fuel tank.

 

[Dejawolf]

Are these sufficient protection values?

600mm is sufficient to stop pakistani KE ammunition.
Chinese ammunition, dunno. but their claims of penetrations ranging from 850 to 960mm are highly suspect given the design of their autoloader has the same limitations as the russian ones, so should be in the range of 550-700mm.
against missiles, it should be able to stop RPG-29 as well as most direct-fire ATGMs, at least if you hit the fuel tank, and it's full.

the lower front hull however is not able to stop Paki KE rounds, and any penetration is probably going to cause aerosolized diesel fumes spewing into the interior.
With a red hot penetrator following up, this is not a good thing. however, if the tank is used correctly, a thinner lower front hull is generally not an issue.

 

[Damian]

1. Its large mantel was requirement and something with IA tactics in thar desert specially engaging enemy at higher depression from above sand dunes..

Size of mantled have nothing to do with gun elevation angles.

Look at M1 series, they have small mantled and still are capable to depress gun up to -9 od -10 degrees. Look at Challenger 1, it have no mantlet at all and is also capable to depress gun to similiar angles.

2. He said Yes, there is no composite Armour behind FCS but metallurgy of plates are thicker composition and harder..

You see. But the plates there can't be very thick, because in such situation you have unnececary weight increase. Harder plates can give you increase in protection why they are still relatively thin.

AFAIK THS steel plates have TE factor of 1.3, which means if THS plate is 50mm thick it is equivalent to 65mm RHA plate.

 

[ersakthivel]

Which question? Protection of the hull?

Is placing armour after the fuel tanks possible? The schematic image above shows little space after the fuel tank.

you should never measure dimensions on schematic, their purpose is to show the arrangement of various assemblies.

You should take dimensions only on production drawings with dimensions marked on it and scale given in a name plate.

So please know that the the values taken from dimensionless schematic will always lead you to wrong conclusion .

No professional will ever accept those values as truth.

 

[Dejawolf]

you should never measure dimensions on schematic, their purpose is to show the arrangement of various assemblies.

You should take dimensions only on production drawings with dimensions marked on it and scale given in a name plate.

So please know that the the values taken from dimensionless schematic will always lead you to wrong conclusion .

No professional will ever accept those values as truth.

i would be happy to use your schematics. just send them over.

 

[Dejawolf]

Size of mantled have nothing to do with gun elevation angles.

Look at M1 series, they have small mantled and still are capable to depress gun up to -9 od -10 degrees. Look at Challenger 1, it have no mantlet at all and is also capable to depress gun to similiar angles.

main reason for Arjun mantlet width is ease of maintenance. you can pull out the whole gun assembly in a fairly short amount of time, without detaching turret.
for abrams and challenger 1, you have to remove the turret to get the gun cradle out.
best of both worlds i think is the leopard 2A5 configuration. narrow mantlet but with armour blocks on either side of the gun that can be quickly removed to pull out the gun.

 

[Kunal Biswas]

Than how come his, words are around only elevation and depression ? , We have not solved the mantled issue here ..

Size of mantled have nothing to do with gun elevation angles..