Arjun Main Battle Tank (MBT)

[pmaitra]

IIRC he's talking about tanks crossing a a large water body where the volume displaced will have a negligible change in the overall water level

I made some formatting changes so as not to confuse two tanks.

Yes, when fording a river, the volume displaced will be negligible, and I should have read the response from @ersakthivel to @p2prada. I had assumed he was talking about testing the tank, like we had seen the videos.

Anyway, I see what he said now. If the river water is 6 foot deep, the tank will not be submerged, snorkel or no snorkel.

 

[p2prada]

It could be possible.

Let's say there is a tanks of water, large enough to hold a 8 foot tank, but has 6 foot deep water. If the tanks is placed in the tank, the water displaced by the volume of the tank, will raise the water level, and yes, the tank could be fully submerged.

P.S.: Think of buoyancy, and how it is computed.

Then that's going to be a mighty small pond if 2 feet of water displaced a weight of 60 tons. I would rather go around it.

Anyway, he is perpetually confused. He confused the terms fording at 6 feet and deep water snorkeling at 15 feet. The latter does not exist on the Arjun.

 

[pmaitra]

Then that's going to be a mighty small pond if 2 feet of water displaced a weight of 60 tons. I would rather go around it.

Anyway, he is perpetually confused. He confused the terms fording at 6 feet and deep water snorkeling at 15 feet. The latter does not exist on the Arjun.

Well, if you were testing the tank, you wouldn't go around it (see the Arjun video), but in real war, yes you would.

Yes, I think he is confused, so was I.

 

[p2prada]

Yes, when fording a river, the volume displaced will be negligible, and I should have read the response from @ersakthivel to @p2prada. I had assumed he was talking about testing the tank, like we had seen the videos.

He said something about Indian Army demonstrating Arjun's ability to be fully submerged in 6 feet of water. Not the exact words..

 

[ersakthivel]

Delay in induction of the new Arjun tanks averted - Frontier India - News, Analysis, Opinion

This information on this site should be read to know more about the comparitively better capability of ARJUN MBT

 

[ersakthivel]

DRDO chief VK Saraswat said the German engine on the current version of the tank would be replaced by an Indian power plant and the new variant (Arjun Mk-II) would have 90% indigenous component. Saraswat, also the scientific adviser to the defence minister, told HT at Aero India-2011: "The new variant will have high indigenous quotient, except for some hydraulic and electronic systems. The tank should be ready in early 2014. It will feature several modifications including superior missile firing capabilities."[76] On June-2011 the Mk-II begun to undergo trials at Pokhran ranges in Rajasthan. The Mk-II is also expected to go through its winter trials later the same year.[77]

According to CVRDE the Director P. Sivakumar, the Arjun Mark II will have a total of 93 upgrades, including 13 major improvements. The major upgrades would be missile-firing capability against long-range targets, panoramic sight with night vision to engage targets effectively at night, containerisation of the ammunition, enhanced main weapon penetration; additional ammunition types, explosive reactive armour, an advanced air-defence gun to engage helicopters; a mine plough, an advanced land navigation system and a warning system which can fire smoke grenades to confuse laser guidance.[78] Other upgrades are an enhanced Auxiliary power unit providing 8.5 KW (from 4.5 KW) and an improved gun barrel,[79] changes in the commander's panoramic sight with eye safe LRF, night vision capability including for driver, digital control harness, new final drive, track and sprocket.[80]

Arjun tank hull and turret has been modified to achieve the target weight of about 55 tons from 59-64 tons. Elbit is helping to enhance its firepower and battlefield survivability and IMI is helping to augment Arjun Mk II's mobility, redesign its turret and hull and improve its production-line processes.

The above is from wiki,whether is correct or not is open to discussion.For example CVRDE chief is reported to have said that turret redesign is underway to reduce weight to 55 tons. But we are hearing ,that the mk-2 that is being tested in rajasthan weighs around 63 tons.SO clarity is not there.A lot of work is going on regarding weight reduction.But a proper facts as of today report is still awaited.

During trials, the Arjun showcased its fording capability, by driving under six feet of water for 20 minutes.[46]

This is what I intended to post.During trials the arjun is reported to have driven UNDER 6 feet of water for 20 minutes.
This is what I quoted.It clearly says under 6 feet of water, not through 6 feet of water, that too with citation.

Arjun Tank already has the capability of medium fording and could remain in medium waters for more than 20 minutes against just 3 minutes of older IA tanks. The Arjun Tank Radiator is capable of using water as a cooling agent when medium fording, where as, the older IA tank's radiator is shut off during medium fording resulting in rise in engine temperature. Even without modifications Arjun Tanks collects only 5-10 liters of water inside in those 15 and more minutes which is of no consequence. Barring some minor instances Indian Army never had to medium ford in both western and eastern borders in 1971. The modifications are more of time consuming mechanical in nature. Indian Army wanted complete ceiling which DRDO promised in future makes.
Read more: http://frontierindia.net/delay-in-induction-of-the-new-arjun-tanks-averted#ixzz2AfK1gV64

The above passage is from the
http://frontierindia.net/delay-in-induction-of-the-new-arjun-tanks-averted
site.

So I an only quoting from events that have already reported to have occured during the arjun trials from reputed sites.I don't say these are gospel of truths.SO if members can advance any arguments against it , we can all debate it in calm and collected manner, we don't have to make personal insinuations and make it a fight.

 

[Kunal Biswas]

There are two huge setbacks in current situation..

1. IMI is ban..

2. Arjun tank Primary designers killed in very weird Car accident..

-------------
-------------

The third Prototype can be of 55tons if news is correct, Presently there are two prototypes..

Arjun tank hull and turret has been modified to achieve the target weight of about 55 tons from 59-64 tons. Elbit is helping to enhance its firepower and battlefield survivability and IMI is helping to augment Arjun Mk II's mobility, redesign its turret and hull and improve its production-line processes.

 

[p2prada]

Fording is done in 1.4m or 4.5 feet of water, for tanks.

This is fording,

Snorkeling, done in 15 feet of water or 5m.

They are both entirely different procedures. In snorkeling the tank is fully submerged in water with only the air pipes sticking out. Arjun has never demonstrated snorkeling.

 

[Kunal Biswas]

Deep fording is not exercised in Indian Army for all tanks..

 

[p2prada]

Anybody would prefer not to use fording or snorkeling during war.

Snorkeling is like the last option, in a no other choice situation.

 

[ersakthivel]

fording is done in 1.4m or 4.5 feet of water, for tanks.

This is fording,

snorkeling, done in 15 feet of water or 5m.

they are both entirely different procedures. In snorkeling the tank is fully submerged in water with only the air pipes sticking out. Arjun has never demonstrated snorkeling.

then what is the meaning of the words,that it remained under 6 feet water ?

 

[ersakthivel]

There are two huge setbacks in current situation..

1. IMI is ban..

2. Arjun tank Primary designers killed in very weird Car accident..

-------------
-------------

The third Prototype can be of 55tons if news is correct, Presently there are two prototypes..

CONSIDERING THE SENSITIVE STAGE OF ARJUN PROJECT WILL mod LIFT THE BAN ON imi?
I hope the new design chief will do the neccassary work efficiently.

http://www.defencetalk.com/forums/army-security-forces/t-98-vs-arjun-657-3/

http://www.defencetalk.com/forums/army-security-forces/t-98-vs-arjun-657-7/

some more discussion on arjun Vs some thing on this thread.

Ok for the guys who have not read much abt Arjun and its capability, I'm putting here some posts made by the Israeli (whom many Indians in here too wud be aware of) who happened to have worked on the Arjun project. I’m posting some of his posts from another forum, so interested ppl can read it and can try to understand that almost all of Arjun’s problem â€" except the new engine - have been resolved beyond belief of the critics and that many new ‘items’ also have been incorporated into the Arjun which finally made the IA to clear it for the production. But that said personally I’d have loved to see Arjun in a totally different way, but then in its current form its as good as it can get and can FIGHT its way out against the best out there w/o any doubt. So not surprisingly every Indian wud be proud of this achievement as this was the very first step to building an indigenous tank and the hard lessons learnt from this 30 yrs of ‘problem solving’ will indeed put the indigenous tank developers in good stead in designing new, upgrading the existing ones and in collaborating on new projects in the future and that’s truly a achievement that the Arjun team has achieved and Hats off to them for pulling it out!

Let me put some info abt the member that the member himself have posted abt him which is all whats needed as of now â€"


I have been with Armour & Systems and for 9 years now and developed 2 very critical sub systems for the Merkava from scratch and were regarded as a breakthrough. My father too worked on these tanks and has his share. Anyway thats me.


So thats the person describing himself , now for his posts abt the Arjun developments as he posted with some modification by me in the posts (not to the substance or his original post) -

Quote:
THE BEAST WALKS THE DESERT AGAIN


Loads of development on Arjun...

- Active area defence system tested to user satisfaction...

- 34/37 successful LAHAT..the 2 fail were tuning trials so actually 34/34 100% hits.. weight is reduced by 1.3 tons.

- No engine problems

- No hydraulic screw ups.

- FCS/BMS/Gen2 TI/ MRI-Ti/ Auto scan and request/ IFF system for strike corps implemented in tank and later same will go to t-90's/72's and finally all mobile units in battlefield. So % kill of friendly is reduced.

- Auto track tested but no one interested -including me as ARM2 (special MRI for Arjun CMDR) scans and beeps at mobile objects on battle field is mis match occurs from scanned input to database.

- AC is working fine - but still not that good. some vents directly fall on FCS/BMS (small ac ducts) to keep temperature down for electronics inside there by keeping overall temp down...this is better as a overall AC is not required and avoids too much load on Engine.

- Its coming out to be a TRUE NIGHT BEAST ... 4km hits and kills are at 100% level on the move at night with ARM2 targeting.

- rotating magazine concept will happen in probably MK3 - so that will have to weight...

- RPG-7 OG7v hits just bounce off the Armour even from rear.

- new nano-carbon aerosol lazer jammer perfected

- two modes of seating one leaning. like challenger and other like Ab.M2 upright...upto user to chose.

- Barrel life counter added to BMS

- self check system further upgraded...simple FIRE WIRE link to onboard system to diagnose tank ..no wire anymore.

- mobile arjun maint. kit 100% complete and tested to user satisfaction.

- For the sighting system...modifications being done to avoid lazer blinders.

- NBC system perfected to AB.Mk2 Sep standard. actually they are the same..we did ToT to India.

- Many other little issues addressed. ...most critiques in Armored units very satisfied..

- summer trials we will re-test and we are quite sure it will do well as most systems were lab tested to worse conditions than in Rajasthan

- independant satcom system added for BMS too..

we see arjun as are adopted baby out here turning out to be a excellent machine...for zeeee night. A Indian serial killer out to rape those little al-kh. he he he...

- Integration tests for air support and Arjun battle target share system(TSS) [part of BMS]tested and 100% A-OK...

- LAHAT launch and air support guiding to target tested and OK too.
Fucccckkkk it will kill a merkava at night...OH GOD WHAT HAVE WE CREATED....
BIG PARTY TODAY


and this too from him replying to the Chinese T-98 and Arjun ...

Quote:
Hi buddy,
I am denil - from Israel and working on the Arjun. I think most of you guys are getting too personal here. Facts are facts.
Buddy i think i can help you out here. Most of the answers to your questions are already in this forum.

Anyway i have been to Singapore and spent some time in assisting Singapore with certain critical upgrades and system design issues. Anyway that is not the point here. I DO KNOW THE T-98 quite well seen the interiors too I guess you have too. The entire tanks metallurgy is MESSED UP... even a RPG -7 will kill the t-98 - sorry but its true. I know about Chinese engineers consulting Israel on these issues. There is talk of a huge assistance from Israel to Chine -but USA is a major bottle neck. You are a market to us - but USA wont let it happen even with some really small issues.

Ok so what do you want to know about the Arjun.

a) On the move it sees you in pitch darkness at 6+KM through MRI-TI devices - ID at about 5.3KM and engage you with comfort at 4.7 KM with super high velocity AP shell..much like the CHARM shell -but much better.

b) At day time it will kill you on the move at 5KM. HeSh at almost 7.5KM.
This tank is no joke my dear man. Its super-chromium lined rifled barrel with revolutionary dual discarding APFSDS shell is a killer.

c) It has as per our own experience and knowledge the fastest AP shot on this planet.

d) FCS/BMS/LAHAT at 6+KM (first people on earth to fire ATGM through rifled barrel using Indian tech of dual cassette disposal- i can explain this in detail to you. But i think someone here can take the trouble to explain CONDOMIZING concept) MRI system etc etc... puts it way out of the t-98.

e) Let me honestly tell you what the t-98 is. It is a honest attempt to make a decent tank and experiment (since there is a lot of money in China to do this) and play with technologies and see what comes out. This one has gone WAY TO WRONG...but nevertheless that’s how all nations learn. next time around most of it will be rectified. Its was also made from a marketing point of view to make some form of dent in the Russian arms market in providing cheap alternates.

f) Metallurgy and China have a long way to go. I know of incidents documented secretly by China and given to El-Op systems for study and rectification - i don’t have the liberty to go into that.

g) Ask what you want on Arjun and i think i will be more helpful. Engine problem (as in Import issue just like the problem with our Merkava's) is being jointly addressed by India and Israel and progress is excellent.


The post below was in reply to the amazing muzzle velocity that Arjun achieved with its 120mm rifled gun , the SECRET ammo of the Arjun which was an Indo-Russian joint development which in all sense will see its use in other tanks in the Indian armory and so will it in Russia and their newer Tanks .....

Quote:
Please understand i will be as liberal as i possibly can be. Certain area's i can not go into depth with.

Q) show how arjun achieve the 5km range with the 120 rifle?
It will be great to get some numbers, like different types of rounds:
1) Their mass,
2) muzzle velocity, Yes way above 1800m/s see if you are doing a standard v=1/m thing here - it will hold little water.

The thing is a 11 yr research which has yelded the hyper velocity (Secret) shell. This is the third type of ammo Arjun fires and is Unique in nature. It is a Joint devp by the Russians and Indians. details of this shell are highly classified. We have fired it and seen the results but have never been allowed to study it. Although we have a fair idea. Its a new type of propelent and a lighter shell (metullargy R&D of Russians) that makes it althought light -making it achieve hyper velocity with a special charge with a crystal tungsten tip giving it penetrations close to a DU round and at the same time a velocity way in excess of what most would be aware off.

Listen i am really short of time...so please do me a favour go here:
scrool down to my 4th post...read it. It will help answer a few of your questions.
4) interior pressure, No can tell


And finally the Super Secret Ammo and the Propellant

Quote:
What nationality is the propellant? German, Israeli or Indian?

Russo-Indian: Israel is very keen on getting its hands on it - till now no success. Germans are aware of it and so are the British for the challenger 2E program. They also want to understand crystallization issues India has had a breakthrough with to develop the Green CHARM 3 ammo. They have been regularly sending requests to negotiate. They saw the demo too and were amazed at the penetration levels... its like rams through any armour you throw at it. We even had our new Armour blocks flown here and it had shown excellent results in tests in Israel. But dam it! Would you know it - it was **** all in front of the Arjun...and that was at some 4.0Km. I keep getting ideas all day long how to stop this round.

these are the stuff posted by an israeli technician who worked on arjun in the above thread.
It is open to discussion.

 

[ersakthivel]

and some more question and answers... hope u guys wud be intrested in reading this ...

Quote:
Q) Sorry for stepping in, but i'm quite annoyed by people here keep saying a rifled tank gun is better while the fact is a smooth bore is obviously superior

Ans)…and that is why I keep saying that this Arjun rifled gun is a accidental find by Indian Engineer’s.
Lets take this point by point and in the process look at the deeper secret of rifled guns, development/advances in chromium lining […gives increased velocity and therefore penetration power to the round, greater precision and reduced wear on the barrel.which is reduced to negligible amount in the Arjun…will explain below] and a Russian high charge shell specially designed for the 120 of Arjun.{sorry can’t say much on this due to classification of technology.}

Q1). The gas seal on a rifled round has to be metal-on-metal contact between the round and the barrel this has a high friction co-efficient -limiting acceleration (see chromium lining as mentioned above) of the rifled round.

Ans] Wrong - overcome by advances in chromium lining and here is what’s new- rounds fired through this 120 are specially designed to reduce friction. This is true for FS-AP and the high power round they developed with the Russians. So rounds fired are a) HesH, b) FS-AP and c) special ammo for high range high impact tank busting (more like a SPIN stabilized round)

Q) On a fin-stabilized round the gas seal can be plastic etc (any suitable low friction material). There are no edges inside the barrel to inhibit acceleration (rifling). So more energy is expended accelerating the round.

Ans] Ok 100% correct (you are saying: “rifling does increase range and accuracy but actually decreases muzzle velocity. As the grooves on the inside of the barrel "grip" the projectile to spin it, they also slow it down) - not valid though. This FS-AP you are pointing out is the one with exposed cone. The AP fired from this barrel is a dual stage projectile. The cone is sealed in a condom type rubber around it with 3 burnable line seals. During travel through the barrel it heats up and burns out exposing the main cone on exit â€" and then separates the sabot jacket. So during travel it is as smooth as a smoothbore with a HIGHER velocity and hence a flatter trajectory, better accuracy and greater penetration. The griping by rifling is thus removed from the concept of FS-AP shots…long rod and otherwise. Also note that the “Greenhill's Rule” is pushed to its limits through research. This is a significant contribution of Arjun 120mm to the MBT’s of the world…if ever the tech is declassified. Our Israli council is working on tech transfer for the same.

… and that’s the reason I had said in my earlier post the British and even the American’s would be interested in this barrel and tech. Apparently these chaps seem to be better in not just software. Believe me I had my opinions about rifling before I saw what I saw.
The reason I didn’t post was because I did’nt have people with your knowledge to share it with.

Q2). The ability to fire a differnt types of ammunitions. This includes missiles and long rod penetrators. (long rod penetrators are long rod like ammunition designed to punch through armour like a "dart". This type of ammunition cannot be spin stablised because the spinning will break the long projectile)

Ans) Missiles are not required by long range powerful guns. Are you saying rifled barrels don’t fire long rods??? Because the do, what do you think the CHARM ammo is! The AP for Arjun is long-rod type. Yes correct spin will break the long rod projectile….again chromium lining and condom’sing the cone was the answer. The spin is actually reduced to extremely slow spin to a point of being negligible …not like a bullet. But note that the Arjun 120mm barrel is one of the most expensive parts of the tank.

Q3). While a rifled helps to stabilise the shell by spinning, it does subject the round to precession. This means the point tends to wander in a small circle. This is less than desirable when you want to punch a hole through armour by brute force.

Ans) same as point 2. Though you are conventionally correct.

Q4). Less wear and tear for smooth bores

While a shell from a rifled gun is marginally more stable over long ranges, this is nothing when compared to the importance of the Fire Control System. With a good FCS, the effect of wind speed and such can be compensated so a fin stablised round can be just as accurate as a spin stablised round.
When we talk about range for tank gun, we talk about the maximum range that the shell can still penetrate enemy armour. In this aspect, a smooth bore gun has better effective range.

Ans) I think these are answered by reading above. Also the “EFFECTIVE” range is of Smooth bore is challenged by rifled hyper velocity long rods which don’t compromise on muzzle velocity and thereby give long effective range.

Q5)Just look at the most modern MBTs in the world, everyone of them saves our own challenger is using a smooth bore gun. Plus our army is talking about switching to smooth bore guns for the challenger 2'sreplacement.

Ans) Correct. The reason why this is a so is due to R&D into various forms of ammo and the diversity achieved in ammo’s and standardization to NATO and cheaper production costs of conventional shells. This is not possible via Rifled guns. The Arjun is designed for this continent with specific objectives and the 3 type ammunition variety more than meet the required demand of the Indian Army. The ground displacement is good, mobility, sensors, crew comfort and ease of driving Superior firepower - to destroy targets (tank/bunker’s) and very good Armour protection.

I would also like to add that Arjun had its 120mm barrel pop out during trials of the Russian high charge ammo about 2 years ago â€" as told to me.

P.S: With developments like the german L55 and DM 53 developments maybe Rifling will have to be droped and smooth bore re-adopted. I guess when R&D started with the Indian's the rifled looked more promising....lets see, time will tell


And this post talks abt the Arjun’s BMS and also of a future version (Mk2 or Mk3?) of Arjun with semi-automatic magazine …..
Quote:
Hi bro's,
I had mentioned the CONDOMISING of rounds on page 1 of this topic...actually i was discussing AP rounds specifically...similar system for LAHAT was adopted here in India and all went fine after 2 tests, the 3rd being made public . This tech of condomizing is 100% Indian. I think you guys are heavily into sex..like writing kamasutra and implementing sexual idea's into tank guns Anyway yes we can say its a Indian-LAHAT. the trix was already there and implemented on this ATGM. Did you know that once lahat is fired from tank A...it can still be guided by Tank B to its target. It is a lang range ATGM. As part of the Arjun BMS system between the tank and other elements on the battlefield - data such as enemy location, target designation can be exchanged with other tanks, or helicopters, artillery, etc., allowing better situation awareness. Moreover, for example a guided LAHAT missile fired by one tank can be guided to its target by another.
Now the idea is to have a MERKAVA type electrical semi-automatic revolving magazine for 10 rounds on standby and the loader coming into action after depletion of these 10. It also increases its ammo capacity.

Yes Arjun fires Long rod TYPE ammo. not a photocopy of CHARM DU type but slightly smaller with a heavy charge...it used to break the targeting sights of Arjun due to the vibration...it was solved though. Isreal is studing the 10 round issue.


The spinoff from 30 yrs of Arjun 'problem solving' also has got itself into the infantry too with the A-7 rifle aka the AK-47 clone to have a good rifled barrel, and so definetely this too wud be the case with the INSAS Rifle and which cud in short mean that India will/has the best rifle ... what do u guys think?

Quote:
Although this may be off topic but i just wanted to tell you that India has a very advanced form of chromium lining tech. this is now being put in all forms of rifling....EVEN THE NEW A-7 ak 47 look alike, result is the penetration power and accuracy of this little toy is astounding... spin off of ARJUN MG to small arms.

-----------------

e] BMS of Arjun is a photocopy of M1A2 BMS + has some stuff from MERKAVA 4 spin off's. If you looked inside - the gadgetry would look better than a Leclerc. Sophisticated touch screen's and all with Gen 2 TI and NOW MRI devices same as MERKAVA Mk4. It will also house the ACTIVE AREA DEFENCE SYSTEM developed by Israel. Has been tested for the same.
Note: Kindly no more discussion on KA-50. You will know when it happens

 

[ersakthivel]

And the reply to the question of wear and tear of the barrel

Quote:
Ok wear and tear: Here is what you are saying

Q: “rifling does increase range and accuracy but actually decreases muzzle velocity. As the grooves on the inside of the barrel "grip" the projectile to spin it, they also slow it down. Not only that it actually wears the barrel down

Ans: This FS-AP you are pointing out is the one with exposed cone. The AP fired from this barrel is a dual stage projectile. The cone is sealed in a condom type rubber around it with 3 burnable line seals. During travel through the barrel it heats up and burns out exposing the main cone on exit â€" and then separates the sabot jacket. So during travel it is as smooth as a smoothbore with a HIGHER velocity and hence a flatter trajectory, better accuracy and greater penetration. The griping by rifling is thus removed from the concept of FS-AP shots…long rod and otherwise. Also note that the “Greenhill's Rule” is pushed to its limits through research. This is a significant contribution of Arjun 120mm to the MBT’s of the world…if ever the tech is declassified.

and a few more questions and answers based on the range and propellants

Quote:
Q a) How have you managed to do an assessment against CHARM?
Ans: The americans did it...we were there for the assessment.

Q b) I’m curious about the HESH of almost 7.5KM. That’s way beyond LOS and makes engagement necessary through prisms or other targeting devices. At 7.5km, I’m assuming that this is an assisted projectile?

Ans: Can not go there
i will address this part first: 8Km is the entire trajectory of the HeSh round. this is nothing more than a capability demo. In actually situation a gunner wont let off the HeSh round at atleast 5.6Km. But this is a phenominal achv. by itself...even now i agree with you..given the terrain where arjun is to be used (Sand Dunes) engagement will be mostly at 2200m to 3Km max. But then again if we change the terrain this excess range of HeSh effective range of 6+Km is a major Advantage. Mind you this HeSh is not our standard TNT/RDX chemical mix...its the new stuff

and to the question of the barrel wear and tear and also the barrel life ...

Quote:
Q) One of the significant issues with bore liners is wear and tear at higher velocities, and there are significant metallurgical issues between the liner and the core barrel. Are you indicating that bore liners are now less of a mating issue with these barrels?

You are 100% correct: this will reamain a issue with Arjun. aFTER ALL THE INNOVATIONS AND BREAKTHROUGS THE BARREL DOES wearout...but it is not a major cause of worry as the wear and tear is better than anything riffled out there-sorry can not reveal exact detail. But take my work...it is not a issue the cmdr will be too worried about.

And that will tell u guys that the Arjun’s rifled gun is something really really different and the best out there and so do the cmdr need not have to worry abt the barrel life coz as said earlier, the Arjun has got a barrel life counter integrated into its BMS

and abt the engine issue, its said that the 1,500hp engine maybe on its way and that summer mean in the post was this summer that passed , but then i hope it don get into Arjun and rather an indigenious one gets in as that wud help reduce costs greatly
Quote:
Q g) If you are still using Russian or Ukrainian engines then I would have a high degree of doubt as to longevity and MTBF issues.

Its a German 1400 engine...almost got the 1500 one ready for trials...will do that this summer. Its looking good.


and abt the new propellant and the time taken for 'solving the problem' of the Arjun
Quote:
One last thing: the propelant was so powerful that it has during the early days poped the barrel out of the tank and broken the FCS with its vibrations...it took 4 yrs just fixing that issue... gives you some idea is HeSh is assisted.
Quote:
and some more question and answers... hope u guys wud be intrested in reading this ...

Quote:
Q) Sorry for stepping in, but i'm quite annoyed by people here keep saying a rifled tank gun is better while the fact is a smooth bore is obviously superior

Ans)…and that is why I keep saying that this Arjun rifled gun is a accidental find by Indian Engineer’s.
Lets take this point by point and in the process look at the deeper secret of rifled guns, development/advances in chromium lining […gives increased velocity and therefore penetration power to the round, greater precision and reduced wear on the barrel.which is reduced to negligible amount in the Arjun…will explain below] and a Russian high charge shell specially designed for the 120 of Arjun.{sorry can’t say much on this due to classification of technology.}

Q1). The gas seal on a rifled round has to be metal-on-metal contact between the round and the barrel this has a high friction co-efficient -limiting acceleration (see chromium lining as mentioned above) of the rifled round.

Ans] Wrong - overcome by advances in chromium lining and here is what’s new- rounds fired through this 120 are specially designed to reduce friction. This is true for FS-AP and the high power round they developed with the Russians. So rounds fired are a) HesH, b) FS-AP and c) special ammo for high range high impact tank busting (more like a SPIN stabilized round)

Q) On a fin-stabilized round the gas seal can be plastic etc (any suitable low friction material). There are no edges inside the barrel to inhibit acceleration (rifling). So more energy is expended accelerating the round.

Ans] Ok 100% correct (you are saying: “rifling does increase range and accuracy but actually decreases muzzle velocity. As the grooves on the inside of the barrel "grip" the projectile to spin it, they also slow it down) - not valid though. This FS-AP you are pointing out is the one with exposed cone. The AP fired from this barrel is a dual stage projectile. The cone is sealed in a condom type rubber around it with 3 burnable line seals. During travel through the barrel it heats up and burns out exposing the main cone on exit â€" and then separates the sabot jacket. So during travel it is as smooth as a smoothbore with a HIGHER velocity and hence a flatter trajectory, better accuracy and greater penetration. The griping by rifling is thus removed from the concept of FS-AP shots…long rod and otherwise. Also note that the “Greenhill's Rule” is pushed to its limits through research. This is a significant contribution of Arjun 120mm to the MBT’s of the world…if ever the tech is declassified. Our Israli council is working on tech transfer for the same.

… and that’s the reason I had said in my earlier post the British and even the American’s would be interested in this barrel and tech. Apparently these chaps seem to be better in not just software. Believe me I had my opinions about rifling before I saw what I saw.
The reason I didn’t post was because I did’nt have people with your knowledge to share it with.

Q2). The ability to fire a differnt types of ammunitions. This includes missiles and long rod penetrators. (long rod penetrators are long rod like ammunition designed to punch through armour like a "dart". This type of ammunition cannot be spin stablised because the spinning will break the long projectile)

Ans) Missiles are not required by long range powerful guns. Are you saying rifled barrels don’t fire long rods??? Because the do, what do you think the CHARM ammo is! The AP for Arjun is long-rod type. Yes correct spin will break the long rod projectile….again chromium lining and condom’sing the cone was the answer. The spin is actually reduced to extremely slow spin to a point of being negligible …not like a bullet. But note that the Arjun 120mm barrel is one of the most expensive parts of the tank.

Q3). While a rifled helps to stabilise the shell by spinning, it does subject the round to precession. This means the point tends to wander in a small circle. This is less than desirable when you want to punch a hole through armour by brute force.

Ans) same as point 2. Though you are conventionally correct.

Q4). Less wear and tear for smooth bores

While a shell from a rifled gun is marginally more stable over long ranges, this is nothing when compared to the importance of the Fire Control System. With a good FCS, the effect of wind speed and such can be compensated so a fin stablised round can be just as accurate as a spin stablised round.
When we talk about range for tank gun, we talk about the maximum range that the shell can still penetrate enemy armour. In this aspect, a smooth bore gun has better effective range.

Ans) I think these are answered by reading above. Also the “EFFECTIVE” range is of Smooth bore is challenged by rifled hyper velocity long rods which don’t compromise on muzzle velocity and thereby give long effective range.

Q5)Just look at the most modern MBTs in the world, everyone of them saves our own challenger is using a smooth bore gun. Plus our army is talking about switching to smooth bore guns for the challenger 2'sreplacement.

Ans) Correct. The reason why this is a so is due to R&D into various forms of ammo and the diversity achieved in ammo’s and standardization to NATO and cheaper production costs of conventional shells. This is not possible via Rifled guns. The Arjun is designed for this continent with specific objectives and the 3 type ammunition variety more than meet the required demand of the Indian Army. The ground displacement is good, mobility, sensors, crew comfort and ease of driving Superior firepower - to destroy targets (tank/bunker’s) and very good Armour protection.

I would also like to add that Arjun had its 120mm barrel pop out during trials of the Russian high charge ammo about 2 years ago â€" as told to me.

P.S: With developments like the german L55 and DM 53 developments maybe Rifling will have to be droped and smooth bore re-adopted. I guess when R&D started with the Indian's the rifled looked more promising....lets see, time will tell


And this post talks abt the Arjun’s BMS and also of a future version (Mk2 or Mk3?) of Arjun with semi-automatic magazine …..
Quote:
Hi bro's,
I had mentioned the CONDOMISING of rounds on page 1 of this topic...actually i was discussing AP rounds specifically...similar system for LAHAT was adopted here in India and all went fine after 2 tests, the 3rd being made public . This tech of condomizing is 100% Indian. I think you guys are heavily into sex..like writing kamasutra and implementing sexual idea's into tank guns Anyway yes we can say its a Indian-LAHAT. the trix was already there and implemented on this ATGM. Did you know that once lahat is fired from tank A...it can still be guided by Tank B to its target. It is a lang range ATGM. As part of the Arjun BMS system between the tank and other elements on the battlefield - data such as enemy location, target designation can be exchanged with other tanks, or helicopters, artillery, etc., allowing better situation awareness. Moreover, for example a guided LAHAT missile fired by one tank can be guided to its target by another.
Now the idea is to have a MERKAVA type electrical semi-automatic revolving magazine for 10 rounds on standby and the loader coming into action after depletion of these 10. It also increases its ammo capacity.

Yes Arjun fires Long rod TYPE ammo. not a photocopy of CHARM DU type but slightly smaller with a heavy charge...it used to break the targeting sights of Arjun due to the vibration...it was solved though. Isreal is studing the 10 round issue.


The spinoff from 30 yrs of Arjun 'problem solving' also has got itself into the infantry too with the A-7 rifle aka the AK-47 clone to have a good rifled barrel, and so definetely this too wud be the case with the INSAS Rifle and which cud in short mean that India will/has the best rifle ... what do u guys think?

Quote:
Although this may be off topic but i just wanted to tell you that India has a very advanced form of chromium lining tech. this is now being put in all forms of rifling....EVEN THE NEW A-7 ak 47 look alike, result is the penetration power and accuracy of this little toy is astounding... spin off of ARJUN MG to small arms.

-----------------

e] BMS of Arjun is a photocopy of M1A2 BMS + has some stuff from MERKAVA 4 spin off's. If you looked inside - the gadgetry would look better than a Leclerc. Sophisticated touch screen's and all with Gen 2 TI and NOW MRI devices same as MERKAVA Mk4. It will also house the ACTIVE AREA DEFENCE SYSTEM developed by Israel. Has been tested for the same.
Note: Kindly no more discussion on KA-50. You will know when it happens

 

[ersakthivel]

all the three posts were from the discussion on that thread.
T-98 vs Arjun - Page 7 - Defense Technology & Military Forum

 

[Kunal Biswas]

@ Ersakthivel, Half of the things people are saying without any link or nothing to back there claims, Many things told there are ok from open source..

 

[p2prada]

It only means the author made a mistake with his English.

Arjun does not have a deep water snorkeling capability and it is most probably not a requirement either.

Arjun has only demonstrated medium water fording capability.

 

[Damian]

Guys, guys wait a moment.

Every tank can have a deep water fording capabilities, what is only needed are long snorkels, especially for one of turret hatches + if nececary also snorkels for engine compartment. Eventually if nececary additional sealings are needed, and that's all.

 

[p2prada]

I suppose, but I was pointing out what stands today.

 

[W.G.Ewald]

Anybody would prefer not to use fording or snorkeling during war.

Snorkeling is like the last option, in a no other choice situation.

River crossing equipment is better. The Russians were experts at that, maybe they still are?

Russian Army - River Crossing Exercise

Russian army units conducting a river crossing exercise.

http://www.liveleak.com/view?i=5c2_1331833859

An old book.

http://collectrussia.com/DISPITEM.HTM?ITEM=7993