Armoured Vehicles Discussion Thread - Jan 12, 2012

[Sanku]

[It is simply a crying shame that the Army played the dirty tricks it did with the Arjun. .

Look boss, if you are going to convert a discussion on tank guns into your quite pointless and incorrect rant about your pet peeves, there is nothing to be discussed.

Meanwhile if you make statements like 1650 is roughly same as 1750 m/s what can we discuss!! Everything is roughly same.

Also, it is a given that smoothbores have longer life than rifled for the same type of round (at the same level of metallurgy, same weight of gun etc) surely you are not going to claim otherwise?

Its 101 of guns!!!

[member_23061]

Aaarree Bhai log! Al Khalid to rifled se bhi marega aur smoothbore se bhi. Why all this acrimony hain? When we have total superiority on a tank v/s tank level .... all this is moot. Let alone we forget that our hawai jahaz force will neuter anything the Paktoon's throw at us. Unless Amreeki's give them Abrams or downgraded ones even.

Indian Army GSQR for the FMBT can be seen as a blessing in disguise too na? To intercept the Chinese armored thrusts, we could use light tanks ..... Arjun to rahega hi. That is decided. T90's and its brethren will not see more orders IMO.

[vina]

Does it make sense to talk about barrel life independent of the round type? It is known barrel life would heavily depend on the round being fired (propellant, velocity, pressure etc) since different stress would be put on the barrel for each type of round.

Not all rounds will have same stress on the barrel --> in this case it is the "design" life in generic terms I guess.

More, Lahore-via-Kuwait from you I guess. That is what the EFC does, "standardizes" the measurement. The Arjun's is published as 500 EFC .

As for your "fanciful" , oh.. the smooth bore MUST be 1900 m/s then, well, it seems that the L55 is 1750 m/s only. And they increased the barrel length rather than designing a new gun ! So unless there is some pet fancy of your's no one is going to design a new gun .

What we have is stupendously brilliant weapon , which is more than enough to handle any existing threats out there, and with enough growth potential if needed.

As I posted earlier, the "smooth bore more efficient" theory has been flushed down the toilet . And it simply blew the Harrumphing by the old Army blow hards "Oh.. rifled gun. out dated.. cant fire APFSD rounds, cant fire missiles" into smithereens.

I am disinclined to believe that FMBT story of smooth bores from Ajai Shukla, unless there is some incredibly pressing operational reason. I cant find any and it doesn't seem to stand to logic from the facts in front of us.

[VibhavS]

^^ Smoothbores are the future of tank guns. Rifled although not lacking in performance atleast none that I could locate over any source..(the search continues) has the additional complication of engineering rounds like APFSDS, Heat, Anti Tank Missiles to prevent the spin from spoiling the effects of the round. Of course rifled guns are inherently accurate, but not by an margin that makes them overwhelmingly superior to smoothbores.
The advent of stablization and computerized FCS systems the accuracy is pretty much in the same range for both types. My guess (stress on guess here) is that rifled guns are getting out of fashion due to the cost factor (NATO has STANAG considerations as well). Cost of barrel wear and change, cost of manufacturing rounds as well, again proof is something that I lack (and the search continues ad naseum).
The debate goes on.....

[Aditya_V]

Have we considered, NATO and Russia Deceided to move to Smoothbore's in the 1970's, now for them to go back rifled may not bring about a cost benefit analysis for them to change their entire Inventory of Barrels, shells, FCS software ittyadi for it? even if today they might think rifled may be better.

[Sanku]

Have we considered, NATO and Russia Deceided to move to Smoothbore's in the 1970's, now for them to go back rifled may not bring about a cost benefit analysis for them to change their entire Inventory of Barrels, shells, FCS software ittyadi for it? even if today they might think rifled may be better.

That is unlikely because any changes in metallurgy APSPDS development which led to shift in smooth bore in 70s, pretty much continue where they are, i.e. no significant development has happened which has changed the picture -- at least as far as I see them.

If you think there are lets do discuss them.

[Sanku]

enough growth potential if needed.

So why is DRDO shifting to smooth bores?

As I posted earlier, the "smooth bore more efficient" theory has been flushed down the toilet .

Says you?

Vs the rest of worlds designers.



I have to say that every point you have raised is either comic rehtoric, avoidance of facts or fudging. (1650 is roughly same as 1750 or 1900.)

Kindly give it a rest -- and accept it, the worlds tank designers do know more than you.

[Aditya_V]

No major developments, but NATO and Russian tanks in the 70's and 80's were developed with large formations of Tank Vs tanks on the field of Europe with less than 2 Km ranges. Such scenario does not apply in Indian context. The L44 gun was initially designed for 400 to 500 round gun life. today with Urban warfare requiring different types of shells and propalents, increase in calibers resulting in Higher pressure the Barrel life is down to just 260 rounds and in some cases 50 rounds. Given that US is only going to fight with super high numerical air superiority and Russia may be using its tanks int he near future in Georgia/ Chechenya type scenario's neither would want to meddle with the logistics.

In the Indian case now that the Arjun Gun along with related ammunition/ FCS has been fully developed there may be no need to Develop smoothbore unless the present gun is shortcoming,

DRDO also has stated the present AFSPDS is good enough for present and near future targets Chinese/ Paki tanks at 5000m with Muzzle veloicity of 1650m and more. IS there any dramatic improvement in Chinese/Paki armor which need to make the muzzle velocity if ammunition go from 1650m and more per sec to upto 1750M as in the L55 and what is impact of such an increase that we need to rework on the enginering, ammunition and FCS for the Arjun's gun.

Lets not make it personal on both sides.

[vina]

Its 101 of guns!!!

Ah, Guru Sanku Maharaj Ji just Harrumphed. It is 101 of guns. Let us see the list of his previous harrumphs from putting feet in mouth that got taken to the cleaners!

1) HESH is "Useless" against concrete fortifications and built up targets for demolition, and is "somewhat" useful only against steel pill boxes
-- Huh.. HESH was shown to be INVENTED specifically for demolition of concrete and is brilliantly effective against such structures and bunds and stuff

2) The HE rounds from the smooth bores are "superior" to the ones fired from rifles.

-- Well, the rifled guns fire a larger shell , packing more ammo , farther and more accurately. Oh oh.. Maharaj is in trouble!

3) The smooth bore is *always* more "accurate" for all kinds of ammo than rifled ones, because of "flatter trajectory" because of shorter v drop from less flying time due to gravity.

-- Well, works only under ridiculous condition of Bhoomi Devi doing differential "keenchayi" for smooth bore over rifled rounds. Maharaj quietly pulls foot out of mouth and says..okay.. same-same onree ,

4) The APFSDS round "must" be faster than a rifled round.
--- Oh well, the Arjun round is faster than any round fired from the L44 version of the Rheinmetall (all the Abrams M2A3 are only L44, only the Leopard II latest versions are 55 caliber).
-- Harrumph. Then the smooth bore must be 1900m/s at least!..Ha ha.. Foot deeper in mouth. Shanghai Stat/Mad Math in support of Lahori Logic ! It is 1750 m/s and that too with a longer barrel and barely out does the shorter barrel Arjun at the least of it's published muzzle velocity!

The Arjun's primary (currently) AND secondary Ammo (potentially) seems to be as good as and far better than the best smoothbore that is out there!

5).. Rifled guns must wear out faster!
-- That doesn't seem to be the case here .

6) And DRDO is now making smooth bore because it has "now" learned how to make barrels..
-- Ha.. Ha.. So they effectively dumbed themselves down to make a simpler barrel!

With so much proclivity for foot in the mouth disease, and some absolutely nonsensical stuff , 101 of guns or not, all the assertions you made don't match reality today and you want to live in your world of make believe.

You are welcome to it of course and not that I care too much for it other than for comedy value.

The reason I took the time to post all this here is to firmly shut up the former blowhards (esp the former folks in uniform) who wrote ignorant or motivated or both , rubbish on this topic (outdated , cant fire APFSDS , cant fire missiles, less effective than smooth bore, wears out faster, more "complex") and each of these points have been proven to be TOTALLY either out rightly false and ignorant/motivated lies or not true in practice as of today.

This was more addressed to them and folks who do look up this thread for general pointers ( it did have important stuff, like Shivji's Gyroscobe and Fins and what it does and doesn't , and how "extra" FCS and data seems to again your wishful imagination like 1900m/s, the current data dont support it) and have a more informed and nuanced view.

As always. Dhanyavad Maharaji Ji.

[vina]

IS there any dramatic improvement in Chinese/Paki armor which need to make the muzzle velocity if ammunition go from 1650m and more per sec to upto 1750M as in the L55 and what is impact of such an increase that we need to rework on the enginering, ammunition and FCS for the Arjun's gun.

I can't think of any with the light weight tanks the Chinese and Pakistanis have (except for one western style model the Chinese have, which could probably be up armored) ..And if the current Arjun gun is made 55 caliber, it will be better than 1750 m/s (maybe it does that even now, dunno, the published specs says 1650m/s above) . I don't think it is needed at all and if it does there is ample room for growth in the current gun.

In fact, other than the Swedish CV-90 based light tank and probably a few others, most of the other light tanks/IFV are using the earlier 105mm RIFLED gun ! Think of it , the latest armored vehicle in US is using the RIFLED gun from the 60s/70s! If like I said, if what happened at sea with Battleships happens on land with Battle Tanks, the gun will become much smaller , and missiles taking the anti tank and anti air role!

[pragnya]

not sure if this has been posted before. an old report dealing with T-90S induction and the issues by Rahul Bedi.

http://www.google.com/url?sa=t&rct=j&q= ... kHZ3Oywr9w

profiles things which is debated and known. however what caught my attention was this -

Tank gun barrels-capable of firing 220 effective full charge (EFC) rounds-were also imperiled. The T-90 can undergo a maximum of three gun changes.

now 2A46M on T-90 have an EFC of 1200 (according to fofanov). so what is correct?? does it mean the EFC of T-90S gun barrel in IA is only 220!! which is less than half of 500 for Arjun!!

Chacko Joseph had attested to it in 2007 report -

Life of barrel of Arjun MBT is twice that of T-90S, estimate equivalent in Effective Full Charge (EFC) of 500.

http://www.freerepublic.com/focus/f-news/2259634/posts

Vina/Anujan - can any of you throw some light on this?? adharmic or dharmic reply is allowed btw.

[Aditya_V]

Lets stick to Inglis replies with just the topic addressed.

[VibhavS]

Here is a bit info for Vina... the chinese are indeed working on heavier MBTs.
http://www.army-technology.com/projects ... nese-main/
Well the new Chinese tank is already reaching 50plus ton weight category checkout the link above. As far as the gun goes it is a smoothbore performance figures quoted from the article below
"Weapon systems for the 125mm tank gun is the APFSDS round. It has a 30:1 length / calibre tungsten alloy penetrator. Muzzle velocity of the round is 1,780m a second and can penetrate 850mm steel armour from a distance of 2,000m."

[VibhavS]

Another rather interesting bit of info. A little while back the Americans decided to test their existing ammunition fired via L44 and L55 120mm guns. Funny bit.
Manufacturers Claimed:
Round Name - KEWA2
Velocity - 1700 m/s from the M256 smoothbore

When the round was fired from the L44 gun at temperatures of 21 *C it performed at the advertised 1700m/s. The same round when despatched from the L55 gun at the same temp was slightly faster at 1750m/s.

The magic happens at 50*C when the round fired from both guns exceeded the manufacturers claimed velocity by a margin of approx 60-70m/s for the L44 and 120-130m/s for the L55 gun.

I dont know if Wikipedia is an accepted source but all Soviet APFSDS rounds are claimed at around 1800m/s. Also found out an old CIA report which puts the velocity at the same figure of 1800m/s.
So 1650m/s is slower aint it?
That means assuming all else is same in case of the penetrator (Length, Diameter, Constituents) the impact from the L55 will be better?

[Sanku]

First >> Aditya_V; thanks for the very sensible posts.

now 2A46M on T-90 have an EFC of 1200 (according to fofanov). so what is correct??

I am not really sure if the various barrel life data floating around can be relied on frankly. This is something which will be held close to the chest and not widely shared.

No major developments, but NATO and Russian tanks in the 70's and 80's were developed with large formations of Tank Vs tanks on the field of Europe with less than 2 Km ranges.

With due respect, I am not sure how much of this is really true. For example the one article that I posted, states that Warsaw pact countries always saw their tanks as multipurpose fighting vehicles and maintained a large variety of effect HE ammunition for close support of troops.

So close support role of tanks has been emphasized as well.

IS there any dramatic improvement in Chinese/Paki armor

The problem here is that we have to assume that Chinese/Paki armor at some time in future may suddenly ramp up with heavier armor. For two reasons
1) It has been known to happen.
2) The Chinese are known to be working on heavier armor.

The problem is that if the Paki/Chinese suddenly move on to heavier armor, we can not then start working on increasing muzzle velocities. The tech/product development must happen BEFORE the threat has emerged. Otherwise we will have to resort to knee-jerk acquisition from external sources.

Secondly, any extra velocity will also make the gun's range effective at higher ranges (simple assumption that with higher initial velocity, higher terminal velocities are possible, or same terminal velocity at higher range)

The range increase would be a good reason to want higher velocities.

[Singha]

looks like the ZTZ99A2 and the Korean K1 tank license the same engine from MTU (MB871ka501), albeit the chinese as usual claim a higher power!

from front aspect the Japan Type90 looks like a smaller arjun
http://upload.wikimedia.org/wikipedia/c ... nk_-_1.jpg

[shiv]

The choice of round used by a tank depends on the type of battle being fought. If it is tank versus tank alone then long range high velocity etc become an advantage. but that advantage could mean nothing if anti-tank missiles and helos are added to the mix. In the India-Pakistan context - Pakistan has a whole lot of bunkers and fixed reinforced concrete fortifications for which HEAT and APSD rounds are not as effective as HESH. India's choices come from the battles we expect to fight.

[GeorgeM]

2) The HE rounds from the smooth bores are "superior" to the ones fired from rifles.

-- Well, the rifled guns fire a larger shell , packing more ammo , farther and more accurately. Oh oh.. Maharaj is in trouble!

3) The smooth bore is *always* more "accurate" for all kinds of ammo than rifled ones, because of "flatter trajectory" because of shorter v drop from less flying time due to gravity.

-- Well, works only under ridiculous condition of Bhoomi Devi doing differential "keenchayi" for smooth bore over rifled rounds. Maharaj quietly pulls foot out of mouth and says..okay.. same-same onree ,

Vina, without interrupting the Hi Explosive discussion you and Sanku are indulging in, maybe we should just make sure that good science is not sacrificed in the otherwise fair exchange. Couple of notes on your last round of exchange
Mechanical efficiency: As you guys have noted rifled vs smooth bore is a classic case of accuracy vs range, the new variable in the equation is FCS which provides as good an accuracy to smooth bore as with rifled. Rifled bore does consume/waste some energy in imparting the spin. But then one has to see the fact that gun is a very inefficient device to begin with, in converting energy. A whole load of energy is released in a very short amount of time and the shell absorbs some of the released energy, going kinetic. Hence the energy dissipation/loss is very high. Add rifling to bore and it becomes even more pathetic due to more friction. So from an efficiency stand point rifle is worse than smooth bore. No matter how good the FCS is, these laws of nature does hold good. So given same mass, length and dia, smooth bore does fire farther than rifled. But again FCS is that moron which throws a kitchen sink into the equation.

Stability/Fatter shell etc: The reason rifled guns are able to fire larger shells( I am assuming 'larger' means fatter, like in bigger dia, D ) is due to the spin stabilty. Lower the LxD ratio (large dia for same length) less is the stability along the L axis. Again laws of nature. How do you jack up the stability then ? Well spin it. The more you spin, higher the stability along L, less the shell wobbles around. Also due to gyroscopic forces , external destabilising forces, like wind gust etc, tend to have much lesser deviating effect from the 'ideal path'. But again more you spin, more is the energy wasted in bore and in flight, less the distance travelled for the same energy input (considering same mass, and LxD) So if you have shell length constraints, to pack more punch, you can make dia larger. This will be an advantage in rifled bore. But when it comes to APFSDS, you need slender projectiles and no energy to be wasted in spinning. All energy needed as kinetic.

Velocity: Shells accelerate only till the tip of the barrel. So more the barrel length more the exit velocity (within reasonable length limits).
It would seem like if the heated exchange is between 'smooth bore with advanced FCS' vs 'rifled bore' then one could end the argument right here in favour of smooth bore with advanced FCS, as I get more range with equal accuracy. But seems like the exchange here is between 'smooth bore' vs 'rifled' and one can argue till kingdom come as it all depends on ones vantage point >> Accuracy or range, shakeela ya katrina.

4) The APFSDS round "must" be faster than a rifled round.
--- Oh well, the Arjun round is faster than any round fired from the L44 version of the Rheinmetall (all the Abrams M2A3 are only L44, only the Leopard II latest versions are 55 caliber).
-- Harrumph. Then the smooth bore must be 1900m/s at least!..Ha ha.. Foot deeper in mouth. Shanghai Stat/Mad Math in support of Lahori Logic ! It is 1750 m/s and that too with a longer barrel and barely out does the shorter barrel Arjun at the least of it's published muzzle velocity!

The Arjun's primary (currently) AND secondary Ammo (potentially) seems to be as good as and far better than the best smoothbore that is out there!

5).. Rifled guns must wear out faster!
-- That doesn't seem to be the case here .

6) And DRDO is now making smooth bore because it has "now" learned how to make barrels..
-- Ha.. Ha.. So they effectively dumbed themselves down to make a simpler barrel!

With so much proclivity for foot in the mouth disease, and some absolutely nonsensical stuff , 101 of guns or not, all the assertions you made don't match reality today and you want to live in your world of make believe.

You are welcome to it of course and not that I care too much for it other than for comedy value.

The reason I took the time to post all this here is to firmly shut up the former blowhards (esp the former folks in uniform) who wrote ignorant or motivated or both , rubbish on this topic (outdated , cant fire APFSDS , cant fire missiles, less effective than smooth bore, wears out faster, more "complex") and each of these points have been proven to be TOTALLY either out rightly false and ignorant/motivated lies or not true in practice as of today.

This was more addressed to them and folks who do look up this thread for general pointers ( it did have important stuff, like Shivji's Gyroscobe and Fins and what it does and doesn't , and how "extra" FCS and data seems to again your wishful imagination like 1900m/s, the current data dont support it) and have a more informed and nuanced view.

As always. Dhanyavad Maharaji Ji.

In the case of Arjun I think DRDO may have taken the safe path, rifled bore due to control system being a very risky development. But it seems like in the end Arjun is blessed with an unique pairing, rifled with advanced FCS. DRDO also seems to have done some magic with metallurgy of the gun as well, not sure if it is brochure bravada, as it has a high projectile velocity (more powder ?) even when fired with contraptions for APFSDS anti spin, which absorb even more energy in rifled guns. Also it seems to have lower wear rate on top. Combined higher velocity and lower wear rate than conventional rifled bore? or even the T-90m smooth bore? oh well I would definitly like to know that magic material. no pun, I know DRDO is capable and has good metallurgy team, and has lesser commercial constraints unlike uncle, but I got to see it in service.

[Sanku]

@Shiv: There are extremely effective HE rounds that can be fired from a smooth bore, especially in a close support role. May be more effective, considering the various effects that can be had with advanced fuzing. None of these will be available to HESH. (This is where the particular discussion restarted in its nth iteration from)

I do not see why HESH is particularly necessary. May be earlier, but today there is no need to make the trade off between anti tank round and bunker busting abilities.

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

Sidharth boss, excellent post, if I may be so bold.

[sudeepj]

Mechanical efficiency: As you guys have noted rifled vs smooth bore is a classic case of accuracy vs range, the new variable in the equation is FCS which provides as good an accuracy to smooth bore as with rifled. Rifled bore does consume/waste some energy in imparting the spin...

Sidharth,

If you are concerned abt the KE of the shell being 'wasted' in spin, (not available to penetrate the armor), you must consider the fraction of the energy thats imparted to the projectile in the spin. The twist rate of the Arjun gun is not available, but assuming it to be 1 in 20 (comparable to the L7 twist), per my back of the envelope calculations, the ration of energy in the spin compared to the linear kinetic energy, is

E_spin : E_linear = 1 : 800 (R/ Pi . r)^2

*Eqn. corrected once.
[
E_spin = 0.5 * I * w^2
= 0.25 * mr^2 * w^2
E_linear = 0.5 * m * V^2

w = V / Pi. 20 R

I = moment of inertia for the dart, = (mass of the dart * radius ^2)/2
R = 120mm, r = radius of the dart.
V = linear velocity, w = angular velocity.

Perhaps someone else can also check this calculation for greater confidence.. I havent solved mechanics problems in ages.. Assumptions are mass and Moment of Inertia of the sabot are negligible as compared to the dart.]

Secondly, its a mistake to thing that friction is more in a rifled gun as compared to a smoothbore. The shell itself rides on the 'lands' (the ridges) in the barrel, while a small copper band makes the shell an airtight fit and makes contact with the grooves in the barrel. Therefore, in a rifled gun, the part of the shell in contact with the barrel is even less as compared to a smoothbore! I fail to see how friction is more in the rifle as compared to the smoothbore. The additional work that frictional forces do goes into imparting spin to the projectile, which as shown earlier, is negligible compared to the total energy imparted to the projectile.

In the case of HESH, HEAT - it doesnt even matter.

It would seem like if the heated exchange is between 'smooth bore with advanced FCS' vs 'rifled bore' then one could end the argument right here in favour of smooth bore with advanced FCS, as I get more range with equal accuracy.

The second thing is, the FCS of the gun can only take into account target acquisition, relative movement, gravitational and atmospheric effects. What it cant take into account is the random yaw/tumbling of full bore (low L/D) rounds. Therefore, the only thing you can shoot accurately from a smoothbore is either darts (APFSDS) or fin stabilized rounds or missiles - the fin stabilization in this case imparting a spin to the rounds as they move through the atmosphere! Anything else will need to be subcaliber. For e.g. http://defense-update.com/products/digits/120he-mp.htm

The other thing to talk about is our tactical and strategic environment. The last *big* full on Tank on Tank battle was Kursk. (Even the middle eastern battles were middling in comparison. Further, one must consider the frontage of the war compared to our fronts.). In all of the Indo Pak engagements, it was at most one regiment of tanks at a time. In contrast, NATO faced tens of thousands of T72s, T62s and so on on their eastern front. They needed a weapon optimized for killing other tanks, and they chose the smoothbore gun.

Further, considering that Tanks are breakthrough and shock weapons, what will be the best counter to these? another strategically difficult to deploy, (relatively) slow moving tank? or a much more mobile, easier to deploy, longer range tank buster (like A10/Apache/LCH..)?

not sure if it is brochure bravada, as it has a high projectile velocity (more powder ?) even when fired with contraptions for APFSDS anti spin, which absorb even more energy in rifled guns

Incorrect here. The only thing spinning is the band, that rides on bearings on the sabot or the sabot itself. In my calculation above, I assumed that the entire dart was spinning, while in reality, the dart spins at a very low rate. The ratio of energy in spin will be even lower than the calculation provided above.

*Edited a couple of times to make certain points clearer.

[sudeepj]

Made a mistake in the calculation above, the ratio is


E_spin : E_linear = 1 : 800 (R/Pi. r)^2
~= 1 : 80 (R/r) ^2

The part I got wrong:-

Assume a linear Distance travelled = 20D (D = bore)
Angle traversed in moving a distance of 20D along the barrel = 2. Pi radians (Since twist rate is 1 in 20).
Take a given unit of time t, in which the projectile travels a distance of 20D. if speed is V and angular speed is w

V . t = 20D
w . t . R = 2. Pi. R (Since one rotation is completed in time t).
Therefore
w = (V . Pi) / (20 . R)

Still, not more than 1.25% of the total energy imparted to a spinning projectile, will be imparted as spin..

Also correcting the post above to avoid confusion.

[vina]

Here is a bit info for Vina... the chinese are indeed working on heavier MBTs.
http://www.army-technology.com/projects ... nese-main/
Well the new Chinese tank is already reaching 50plus ton weight category checkout the link above

Yes, that is the "western" style Chinese tank I wrote about. It does have the same T72 type autoloader and ammo storage. So it still is a "Human Tandoor " (okay,the poster who coined that term can claim copyright), Model 99.

[Singha]

with both ukraine and russia demoing bustle mounted autoloader pulling rounds from protected slots, I would be most surprised if the PLA did not make a move to it. its not a rocket science and Leclerc has it from day1.

the way I see it , they are slowly moving to a 55t tank . the T90MS can at best match these tanks but cannot overmatch it unless it gets a abrams std gun/ammo/networking and sensor pkg. this is not going to happen as Russia does not have it and there is no plan for a bustle loader to make rounds longer.

only the Arjun can overmatch these with the planned improvements, but logistically moving and supporting big tank units into Ladakh or north sikkim has its own problems, while the chinese have the gentle slopes and vast open areas of tibet to stage from and run around in, plus the railways they are building.

we need a long term plan and vision about how to deal with the chinese armour threat in tibet and sikkim
[a] tanks + Namica + gunships + arty
Namica + gunships + arty
[c] gunships + arty
[d] fervent prayers ? hope not.

no bulk orders have been placed for namica - the IA does not give the feel of being enthu about it as a game changer. instead they look keen on billion$ order for javelin whose range is 50% of Namica and has to be deployed by infantry teams.

[Gurneesh]

^^^^ Namica is the BMP based carrier for NAG anti tank missiles.

IA is happy with NAG but wanted some changes in NAMICA (and that too right after NAG cleared trials and production should have started).

But Nag and Javelin are in two different categories. Javelin is Man portable unlike Nag, while Nag is more potent, has more range and is also heavier (and larger).

Javelin should be compared to the outdated Milans that IA currently operates.

[srai]

^^^

Regarding NAMICA and NAG, according to recent news reports the IA has a requirement for 200 NAMICAs and 7,000 NAGs.

[vina]

Mechanical efficiency:
Stability/Fatter shell etc:
Velocity:

1) Yes, smooth bore will have higher mechanical efficiency, for the same reasons you posted

2) You need fin stabilization if you fire a smooth bore , unless you are firing cannon balls. Even with cannon balls, the accuracy beyond say 400/500 yards historically was pathetic (okay, the ancient machining tolerances were not close to what is done today, but still)

3) Velocity. I think you need to be conceptually clear on this. Tanks fire APFSDS and other types (HEAT and if rifled HESH in addition)
a) APFSDS - Yes, smooth bore will have no rotational energy component. All energy will be 100% KE. However, rifled bore too will be nearly equally good. How so ? I posted to"Maharaj" that the sliding band is like a bangle,that slips around the sabot, look that up. No need to spin anything else. Now the moment of inertia of that is I = mr^2 , m is a few grams, r is 120mm.. Convert that into Kg and Meters and calculate I , the moment of inertia and rotational kinetic energy and compare that with that of the penetrator with mass in Kilograms and v in order of 1500+ m/s and you can see how negligible and minuscule that loss in spinning the band is . It is a non issue really.

b) For all other rounds, whether smooth bore or rifled, they go out at very similar muzzle velocities of around 750 to 900 odd m/s. In that situation, an optimal ballistic shaped, full caliber round is far more efficient aerodynamically , carries more explosive to target and is more accurate , which is possible because of spinning (lesser Velocity drop because of superior ballistic coefficients possible .. no lift induced drag due to fins, etc, thanks to Vayu Dev.. whom I hinted to Maharaj, who insisted on praying only to Bhumi Devi only, what to do.. that was Maharaj's answer to the question on differential " bhumi devi ki keenchayi".)

That is why historically, guns went from being smooth bore for a few hundred years to being rifled ever since. The point is to be able to deliver the round accurately over a longer distance.

Sure, there are effects because of the spin (it will generate lift-positive or negative based on wind direction- Magnus effect) that affect range and aiming and need to be considered. Same effect use in tennis where today's players hit predominantly with a heavy top spin and not flat like the yesteryears, because you can consistently drop the ball inside the baseline when you hit that way , though a ball hit flat will travel faster and flatter ,like from a smooth bore, but overshoot the baseline far more because of poorer control ( Mahraj Ji doesn't play tennis I think)

Consider the famed Gerald Bull, who probably did the most pioneering research on smooth bore and fired more stuff from smooth bore (shell,s rocket models, aircraft models.etc) , higher and further than any man ever, did not build a smooth bore howitzer or field gun., even when the South Africans, Iraqis etc were looking to build brand new weapons.

[Aditya_V]

Here is a bit info for Vina... the chinese are indeed working on heavier MBTs.
http://www.army-technology.com/projects ... nese-main/
Well the new Chinese tank is already reaching 50plus ton weight category checkout the link above. As far as the gun goes it is a smoothbore performance figures quoted from the article below
"Weapon systems for the 125mm tank gun is the APFSDS round. It has a 30:1 length / calibre tungsten alloy penetrator. Muzzle velocity of the round is 1,780m a second and can penetrate 850mm steel armour from a distance of 2,000m."

So the Chinese are moving to a Western type heavy amour Tank with many features in the Arjun, Pakis will surely a get a few hundred of these. Good thing the Arjun project was not killed in spite of many attempts, cause when CHiniPak start inducting them we would have gone for emergency purchase of Western tanks at exorbitant prices.


No doubt the T-90S is good tank and T-72 need need to get their FCS updated for Day/night operations and turrents run of electric motors, but the Torsion Bar and relative light weight Armour which can be advantage in some scenarios can be a disadvantage in Tank battles with the heavies.

[Rahul M]

how exactly would the T-bar or light armour be an advantage ?

[vina]

with both ukraine and russia demoing bustle mounted autoloader pulling rounds from protected slots, I would be most surprised if the PLA did not make a move to it. its not a rocket science and Leclerc has it from day1.

the way I see it , they are slowly moving to a 55t tank . the T90MS can at best match these tanks but cannot overmatch it unless it gets a abrams std gun/ammo/networking and sensor pkg. this is not going to happen as Russia does not have it and there is no plan for a bustle loader to make rounds longer.

only the Arjun can overmatch these with the planned improvements

You know how these things work. Chinese are transferring a few hundred of Type 99 to the Pakis.. OMG, the T-90S cant take them on, quick , a rush order of the T-90 M or whatever with the bustle mounted autoloader and long rod rounds placed, which will be "indigenized" over time, and "joint development" of the "New Russian Object", which seems like a Russian take on the Merkava as the FMBT or whatever! That is the history of these things here.

[Aditya_V]

how exactly would the T-bar or light armour be an advantage ?

Well light weight was considered an advantage by IA for its logistics and bridges etc, in both Pakistan and India may not support the heavier weight, T-Bar I guess was something IA was familiar with so logistic crews had to be trained in maintaining the Hydropneumatic suspension.

Hell, some in IA and media till recently even maintained that A/C in Arjun was bad as not subjecting soldiers to 550 C would make them soft

[VibhavS]

Yes, that is the "western" style Chinese tank I wrote about. It does have the same T72 type autoloader and ammo storage. So it still is a "Human Tandoor " (okay,the poster who coined that term can claim copyright), Model 99.

Well agreed that the autoloader still exposes them to the same tandoori experience that is guarantee in the T72 and the T90. My only point is that it will be converted into tandoor only after you have managed to pierce the armor right? With the kind of armor that thing is sporting it will take some time (conjecturing here... 1000~1200mm RHAE equivalent armor from some figures being bandied about online...) atleast a few rounds of APFSDS? My thought here is I would rather be in a highly protected tandoor and than a lessor one.

[Singha]

ztz99 sports heavier armor fr sure
in arjun we have a good platform to build on bring in new stuff to keep them off balance...
t90 cannot do it...its end of line product...russia is breaking frm that line fr next tank

[VibhavS]

^^ Agreed, T90AM is a colossal waste of time and financial resources better spent in getting more Arjuns into service and putting upgrades on the same.

[Sanku]

All energy will be 100% KE. However, rifled bore too will be nearly equally good. How so ? I posted to"Maharaj" that the sliding band is like a bangle,that slips around the sabot, look that up..

Such "nearly equally good" comments are thorough junk mean nothing frankly.

So is harping on a slip ring as if it is great invention. Slip rings have been around since 1940s, when it was first discovered that spinning mutions had issues in various contexts (reading up on it is trivial)

The point is simple, is the slip ring 100% perfect (that is NO spin is imparted to the round) or not.

Obviously any mechanical system can not ensure 100% decoupling, I will leave it as an exercise of those who think (1650 == 1750 == 1900) to actually find out what is the efficiency of a slip ring in practice and how much of spin it isolates, and how much it passes on.

Vina is butchering basic physics and engineering here.

[vina]

Such "nearly equally good" comments are thorough junk mean nothing frankly.

Oh , indeed, so reality intrudes very rudely indeed into your make believe world , and trashes your "oh.. must have significant loss due to rotational kinetic energy.. because I think so"..

Why this is perfectly on the lines of what.. 1650m/s from rifled gun, it MUST be 1900 m/s from smoothbore then , reality be damned kind of shanghai stat and madrassa math in support of Lahori logic!

So is harping on a slip ring as if it is great invention. Slip rings have been around since 1940s, when it was first discovered that spinning mutions had issues in various contexts (reading up on it is trivial)

It must be equally trivial to note then, that it is extremely simple , cheap , effective from the same sources. So why then, Maharaj Ji, if your "Knowlijj" was so profound that a whole series of your ilk, yellow journalists, Natashas and a whole troop of Uniformed Harrumphs, go on and on about..oh.. rifled gun, obsolete, CANNOT fire APFSDS, cannot fire missile. Maybe, once you are "ejjucated", you can go back and rewrite what you wrote ?

The point is simple, is the slip ring 100% perfect (that is NO spin is imparted to the round) or not.

Maharaj Ji, you probably dont play tennis to appreciate top spin, but surely you ride a bicycle, why dont you sit in a bicycle and crank the pedal BACKWARDS , see how far you go and then decide whether the slip ring mechanism there works 100% perfectly or not ? Simple no? Even a kid can do it.

Obviously any mechanical system can not ensure 100% decoupling, I will leave it as an exercise of those who think (1650 == 1750 == 1900) to actually find out what is the efficiency of a slip ring in practice and how much of spin it isolates, and how much it passes on.

Translated in Inglees, it means YOU have zero ability to do the exercise, cant even get your arms around it and have no clue how to do it,cant deal with real world data and facts and expect, data to fit your pre conceived world views (oh.. it MUST be 1900m/s then.. )!

Vina is butchering basic physics and engineering here.

Indeed. So are a lot of others who actually seem to be doing it for a living and funnily enough their butchering works, but Maharaj's Hawaa-bazi is just that.

Ask Unkal Googal the Qustion "Slip Band Obturator" and the first hit that pops up is a pdf link titled Branch Name . Click on "Quick View" , not on the link(which doesn't work) and you get to see a presentation titled "Composite Sabot Technology for 105mm Gun System" by a person with Ultra-Ultra SDRE name called Velan Mudaliar (gosh.. if he was wearing his dhoti , he would be in the DRDO), of the US Army - Armament Research,Development and Engg Center, Picatinny Arsenal.. dont worry, it is Unclassified , no FBI spooks are going to show up at your door step, published Aug 2011.

Oh, yeah, they are doing engg development on the self same 105mm RIFLED gun (the Royal Ordnance L7, that was made in India as well) as of 2011 , so not "obsolete" by any stretch, and in fact,present on the latest armored vehicle in the US inventory and horror or horrors, just like the Arjun, that is a unitary round with slip band obturator (oh.. the Bangle is against all laws of Physics.. Maharaj Harrumphed earlier.. must be make believe Maharaj Fyzzics I am sure), and in that presentation in the slide titled "Torque in 105 mm gun system" , there are three very interesting graphs, that has prediction models on the torque from band slip, time histories of spin rate and pressure. The torque graph is incredibly interesting..

Let us see Maharaj's "spin" (pun intended) on that and his ability on getting data and trends on graphs,how it will translate in the real world, how it squares ith his experience in sitting and pedaling his bicycle backwards and how it tallies with this particular application of the spinning band! It will be interesting to hear it !

And if anyone thinks that it must all be so "incredibly expensive" look at this Link for M242 Auto Cannon and scroll down to M919- Armor piercing FSAPDS-T, which like the Arjun's is also a fin stabilized round, fired from a rifled gun, it has a NYLON obturating slip band (oopps.. Maharaj need to take of lot more grams out of the moment of inertia calculations from an already low base.. ) and is listed as $98 , and mind you, this is a DU round!

[vina]

And oh.. setting aside Maharaj Ji's ignorant rants and harrumphs from Google reading, let us see, what the ARDE (the DRDO lab for the Arjun gun) have to say in their Achievements

One of the most prestigious and ambitious weapon system project undertaken at ARDE is the 120mm Main Armament and Ammunition system for the ARJUN MBT. This is a high-technology program involving a number of disciplines. ARDE has developed a super velocity gun and a family of ammunition with FSAPDS as the primary kinetic energy kill mechanism. It can be confidently stated that the fire power of ARJUN would be comparable with the contemporary MBTs available in the world. It may be noted that only four gun systems in this performance class have been developed abroad namely in UK, Federal Republic of Germany, France and Russia. Even the US and Japan have opted to adopt and licence produce the German 120mm Rheinmetall gun. Our Scientists and engineers, therefore, are justifiably proud to have joined this exclusive `club" with totally indigenous technology. The armament and ammunition system are under current production at OFB.

They truly have every reason to be proud of their achievement. It is a stupendous success. Kudos to them.

Also, notice this picture (also on ARDE achievements page) from DRDO tech focus.. dated 1999 . I can definitely see a canister round, another saboted round, in addition to the APFSDS and the HESH round that is currently advertized. Hmm. This tallies with what Ajai Shukla said in his blog recently on "new rounds.. dont ask, wont tell" . There is more under the table.

But notice the date, it is 1999 for heaven's sake, when this gun and armor were performing superbly , and the Natashas, Yellow Journalists and the Uniformed folks and senior brass were going Ape-S*it on the lines of "Obsolete, cant fire rockets, cant fire this " rubbish. Even, the pre -reformed Version 0, wet behind the ears journalist Shukla of the "beer buddy with Generals" sprouted the exact same rubbish.

It took them the better part of the decade to shut them up firmly.

And oh yeah, the DRDO sabot , currently is an aluminium sabot. You do the engineering to go to a composite sabot, like what Ultra SDRE Velan Mudaliar is doing with the US ARDECOM , you can get the speeds up further if needed. It is just bread and butter engineering work and incremental improvements from here.

But rather than put nose against grinding wheel and doing it, our Army folks seem to be given more into brochure reading on the lines of Maharaj Ji and just wildly extrapolating theoretical ideas into real world, without any consideration for reality and how things actually are on the ground.

[VibhavS]

Vina you are right about Sabot rounds they can be fired from rifled guns and are being fired no problems there. Yes a slip band is used to ensure minimizing the effects of the spin on the round (eliminate it even).
The author of the presentation also highlights the approaches being taken to counter act the shear force on the penetrator rod. (of course they are simaltaneously trying to lighten the round). It is this shear that reduces the effectiveness of sabot rounds fired from rifled guns. The lack of this force when firing from smoothbores results in ability to achieve higher muzzle velocities plus retain structural integrity of the sabot for more effectiveness.
That does not mean that the smoothbore gun is more accurate etc etc it only means that it can fire a sabot round with less complications. Allowing designers to focus on improving the velocity, penetration ability of the gun/weapon system as well as the round/ammunition.

[Austin]

^^ Agreed, T90AM is a colossal waste of time and financial resources better spent in getting more Arjuns into service and putting upgrades on the same.

Eventually our T-90 Bhishma will get upgraded to T-90MS standard during their life cycle time when they are eventually modernised , its just an add on kit for existing T-90

[VibhavS]

[quote="Austin]Eventually our T-90 Bhishma will get upgraded to T-90MS standard during their life cycle time when they are eventually modernised , its just an add on kit for existing T-90[/quote]
Ah the follies of men!!! , but looking at the bright side atleast it may come with an A/C and improved protection thanks to getting rid of the tandoori style autoloader. Thanks for the info Austin.

[rohitvats]

^^^How on god's earth are you going to add a bustle auto loader on IA's T-90 without tearing up the turret???? Or are we looking at replacing the turret lock-stock and barrel? Whatever it is - I don't see bustle auto-loader making it to IA. Otherwise, the cost would be too much. The whole auto-loader plus ammo stowage thing would need to be put in place a fresh. Not happening, IMO.