Arjun vs T90 MBT

[pmaitra]

Most commonly HMX, PBX, RDX etc. Many different types of explosivs as far as I know. You should rather try to search explosives used in specific type and models of projectiles. For example M830/M830A1 is reported to be loaded with Composition A3 Type II explosive. Source is FAS (Federation of American Scientists) and Jane's.

Good answer. Thank you. RDX is >90% of C4 explosive used in some HEAT munitions.

Now tell me, what is the flame temperature of RDX?

 

[Damian]

Dunno (no source avaiable), however you should take in to account that even if temperature is at melting point of specific material, it does not mean that this material will melt, as time is nececary. For example, make a small experiment, try to melt a piece of copper and meassure time needed to melt it, then search time of explosion and how fast shaped charge jet/stream forms and remember that even when jet is formed, it is moving from the beggining away from the explosion center.

I believe more engineers who design shaped charges, that there is no melting or other such nonsences.

Oh wait I found something.

http://www.teledynerisi.com/products/0products_8td_page02.asp

There are provided reaction temperatures.

 

[pmaitra]

Dunno (no source avaiable), however you should take in to account that even if temperature is at melting point of specific material, it does not mean that this material will melt, as time is nececary. For example, make a small experiment, try to melt a piece of copper and meassure time needed to melt it, then search time of explosion and how fast shaped charge jet/stream forms and remember that even when jet is formed, it is moving from the beggining away from the explosion center.

I believe more engineers who design shaped charges, that there is no melting or other such nonsences.

Oh wait I found something.

Teledyne RISI Inc.

There are provided reaction temperatures.

You'll have to excuse me, I will respond back once I go home. That way I can also provide references. So please bear with me.

 

[Damian]

Here is something interesting I found, tests from US Army on RDX.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA502805

It says that RDX explosion, for 5 seconds, generates ~250 °C. Copper melts at 1084,45 °C

The jet travels in hypersonic speeds, so the tip moves at 7 to 14 km/s, the jet tail at a lower velocity (1 to 3 km/s), and the slug at a still lower velocity (less than 1 km/s). (as per article on Wikipedia says), so it is just immposible to melt the copper liner.

Also take a note of this x-ray photo which shows shaped charge jet during penetrations, it is fragmented and definetly does not like a molten metal, but rather solid metal fragments.

 

[pmaitra]

Will copper melt?

At < 1 MPa pressure, flame temperature of RDX is > 3000 K.

Exhibit 1:

Spoiler

Source: Preview

Note: Temperature increases with pressure.
​

Exhibit 2:

Spoiler

Source: http://www.kinetics.nsc.ru/comp/comp2009/Paletsky_2.pdf
​

At 0 - 5000 MPa pressure, melting point of Cu is < 1500 K.

Exhibit 3:

Spoiler

Source: http://www.ucl.ac.uk/EarthSci/people/lidunka/papers/48.pdf
​

[HR][/HR]

@Damian, @ersakthivel, @Decklander, @Kunal Biswas

 

[pmaitra]

Here is something interesting I found, tests from US Army on RDX.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA502805

It says that RDX explosion, for 5 seconds, generates ~250 °C.

It does not say that RDX generates ~250 °C. Read it properly.

[HR][/HR]

You have absolutely no idea of the Centigrade or Kelvin scale, neither do you have any idea about flame temperature of RDX.

Heck, even Candle produces more flame temperature than RDX, as per your claim of RDX's temperature.

Wax Candle:

Source: Chemistry of the Christmas Candle — Part 2 :: ChemViews Magazine :: ChemistryViews

Tobacco:

Temperature distribution inside a burning cigarette


R. R. BAKER

Group Research and Development Centre, British-American Tobacco Co. Ltd, Regent's Park Road, Southampton SO9 1PE

THE study reported here has been undertaken to resolve the large discrepancies between reports of the temperature distribution in the combustion coal of a cigarette. Studies using bare thermocouples (refs 1–4 and R. G. Hook, paper presented at Twentieth Tobacco Chemists' Conference, Winston-Salem, North Carolina, November 1966) indicate that the highest temperatures occur on the central axis of the coal (the actual reported values vary considerably but are usually in the range 800–900° C during a puff, 700–800° C during the natural smoulder between puffs, and 800–850° C under steady state continuous draw conditions). Under all smoking regimes, the thermocouple-measured temperature decreases by up to 300° C along a radius from the maximum central temperature to the periphery of the coal, although one thermocouple study2 has reported the occurrence of occasional peripheral hot spots, with temperatures higher than the centre of the coal. (Ref. 2 contains a comprehensive compilation of more than forty studies of temperature measurements inside burning cigarettes prior to 1968.) In contrast, temperature measurements by X-ray observations of the melting of small metal particles placed within the cigarette5 indicate that the highest temperatures (900° C) occur at the periphery of the coal. Furthermore, measurements of the coal's surface temperature by radiation methods (ref. 5 and A. T. Lendvay, F. M. Watson III, and T. S. Laszlo, paper presented at the CORESTA/Tobacco Chemists' Joint Conference, Williamsburg, Virginia, October 1972) have recorded temperatures of about 850–920° C during a puff, 700° C (below the surface ash) during smoulder, and short-lived hot spots on the coal's surface as high as 1200° C (ref. 5).

Source: http://www.nature.com/nature/journal/v247/n5440/abs/247405a0.html

[HR][/HR]

@Damian, @ersakthivel, @Decklander, @Kunal Biswas

 

[pmaitra]

No I am talking about the combined thickness of both the outer tool box wall the inner wall of the crew compartment.i am most interested in the inner wall of the storage box.because even for a cursory glance it sems the outer toolbox walls are way too thin.

@Kunal Biswas can give a better answer. He has seen Arjun first hand.

 

[Kunal Biswas]

Its been long time, though each side of tool boxes will give a 20mm of thickness..

These boxes carry some heavy gear..

@Kunal Biswas can give a better answer. He has seen Arjun first hand.

 

[shiphone]

according to our text book, normally the temperature of shaped charge jet created by Gathering energy effect is between 900-1000 ℃ . so the copper( melting point 1083℃ ) couldn't be molten. this metal jet actually is not a ' fluid ' but more like a 'Forging' metal fragment...

Armour penetration effect of HEAT is combined with High temp(max.1000℃), high speed(around 10 KM/S) and high presure(the diameter of the tip is just several millimeters )

before hitting the armour...normally the jet is a single carrot like this, the tip is small, has the much higher speed and the rear part has more weight but much lower speed. we should keep the height of burst in contrl to prevent the fragmentation of the jet before hitting the armour

 

[pmaitra]

according to our text book, normally the temperature of shaped charge jet created by Gathering energy effect is between 900-1000 ℃ . so the copper( melting point 1083℃ ) couldn't be molten. this metal jet actually is not a ' fluid ' but more like a 'Forging' metal fragment...

Armour penetration effect of HEAT is combined with High temp(max.1000℃), high speed(around 10 KM/S) and high presure(the diameter of the tip is just several millimeters )

before hitting the armour...normally the jet is a single carrot like this, the tip has the much higher speed and the rear part has more weight but much lower speed. we should keep the height of burst in contrl to prevent the fragmentation of the jet before hitting the armour

Depends upon what kind of material one uses for the plastic explosive. If RDX is used, the temperature will be, well, I have already posted the data.

More info:

The primary warhead used for HEAT (High Explosive Anti-Tank) projectiles is the shaped charge. A variant on the theme is the SFF (Self-Forging Fragment), or EFP (Explosively Formed Projectile), where a metallic plate is put at the front of the shaped charge. The plate is melted and accelerated forward at great velocity (1-2 km/sec), not as fast as the jet in a conventional shaped charge, but still useful. This variant gives it a greater range than the conventional jet, up to hundreds of CDs instead of just 10.

Source: What is a Shaped Charge?

Low-melting-point (below 500 °C) solder/braze-like alloys (e.g., Sn50Pb50, Zn97.6Pb1.6, or pure metals like lead, zinc or cadmium) can be used; these melt before reaching the well casing, and the molten metal does not obstruct the hole. Other alloys, binary eutectics (e.g. Pb88.8Sb11.1, Sn61.9Pd38.1, or Ag71.9Cu28.1), form a metal-matrix composite material with ductile matrix with brittle dendrites; such materials reduce slug formation but are difficult to shape. A metal-matrix composite with discrete inclusions of low-melting material is another option; the inclusions either melt before the jet reaches the well casing, weakening the material, or serve as crack nucleation sites, and the slug breaks up on impact. The dispersion of the second phase can be achieved also with castable alloys (e.g., copper) with a low-melting-point metal insoluble in copper, such as bismuth, 1–5% lithium, or up to 50% (usually 15–30%) lead; the size of inclusions can be adjusted by thermal treatment. Non-homogeneous distribution of the inclusions can also be achieved.

Source: http://en.wikipedia.org/wiki/Shaped_charge#Liner

N.B.: Easily melting liner has its advantages.

HEAT Rounds
Modern tank armour is much more useful against HEAT rounds. Reactive armour, which explodes upon contact by incoming rounds, diffuses much of the energy of a HEAT round. Honeycombed ceramic layered between steel plate can literally soak up the warhead's molten metal and any metal of the tank's armour that the shaped charge has melted. HEAT rounds can be used against other tanks and softer targets such as armoured personnel carriers, infantry fighting vehicles, trucks and helicopters. The M1 has some anti-helicopter capability, which is a new development in armoured warfare.

Source: http://www.ehow.co.uk/info_8710072_happens-tank-shells.html

 

[LurkerBaba]

It does not say that RDX generates ~250 °C. Read it properly.

It says that the 5 second explosion temperature of RDX is 250 °C. Post explosion an explosive becomes a gaseous mixture.

 

[Patriot]

Army Opts For T-90s Battle Tanks

Top army generals are undermining India's Arjun tank to push through a Rs 10,000 crore order for T-90MS tanks from Russia.

Top army generals are undermining India's Arjun tank to push through a Rs 10,000 crore order for T-90MS tanks from Russia. Senior defence ministry (MoD) sources tell Business Standard that Arjun trials, proposed for the plains of Punjab, are being scuttled to prevent any high-profile Arjun success from jeopardising the import of more T-90s from Russia.

A proposal from the tank directorate for Arjun trials in Punjab has been placed on the backburner after instructions from the Military Operations (MO) Directorate. The powerful MO Directorate, more than any other branch of the army, deals directly with the army chief.

At stake here is the Rs 10,000 crore purchase of 354 new T-90MS tanks for six tank regiments for the China border. Business Standard had first reported the raising of these regiments (Sept 17, 2012, "In a first, Indian tank brigades to defend China border"). In the proposal that the government is considering for two tank brigades and a mountain strike corps, the army has put in the cost of 354 T-90MS tanks.

These new tanks will supplement the 1657 Russian T-90S, and 2414 T-72M tanks already deployed on the Pakistan border. So far, there are just 128 Arjun tanks in service, with an order for another 118 in the pipeline.

Contacted for comments, the Indian Army denies that the MO Directorate is blocking any trials.
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"The army is justified in wanting the T-90MS for the China border. But it is wrong in scuttling the induction of the Arjun in Punjab and J&K. The Arjun must be given a fair chance. How can a Russian tank be given preference over an Indian one?" says a senior armoured corps general who is still in service.

The six tank regiments being bought for the China border will be divided between two armoured brigades, one located in Ladakh, and the other one in the north-east. Both sectors have valleys and plateaus in which China could attack with tanks. The new tank formation will safeguard these approaches and also provide a retaliatory capability in case of Chinese attack.

 

[ersakthivel]

Its been long time, though each side of tool boxes will give a 20mm of thickness..

These boxes carry some heavy gear..

What is the width of the storage box(the distance between the two walls)?
can it be modified as a cavity for composite armor?

 

[Damian]

@pmaitra I have an interesting information for you, although without source right now. I read somewhere that best liner for shaped charge warhead is amrphic material, like glass, however glass is not perfect, so the better solution would be amorphic metal alloy, I know that Americans are working on many applications in military for amorphic metal alloys.

Besides this as I said, remember how qucikly jet starts to move, for example after 5 second RDX is 250 °C, but the jet is allready moving 7-14 km/s from the begginign of explosion, where it be after 10 seconds when temperature of explosion might be higher?

 

[ersakthivel]

Arjun Main Battle Tank - Army Technology

The development of Arjun MBT began in March 1974. The tank heavily depends on foreign technology and equipment. Krauss Maffei, developer of the German Leopard 2 tank, provided the design assistance. Hence, the Arjun closely resembles Leopard 2A4 tank.

The newly developed Kanchan modular composite armour gives all-round protection to the tank from anti-tank ammunition. Kanchan has been manufactured by Defence Metallurgical Research Laboratory (DMRL) armour design and development division.

The armour is made of composite panels sandwiched between rolled homogeneous armour (RHA), which can defeat APFDS or HEAT rounds. The turret houses lightweight compact Kanchan armour. An option is also available to add explosive reactive armour. Mobile camouflaging system (MCS) technology is also being developed by the DRDO in collaboration with Barracuda Camouflaging Limited.

The newly developed Kanchan modular composite armour gives all-round protection to the tank from anti-tank ammunition. Kanchan has been manufactured by Defence Metallurgical Research Laboratory (DMRL) armour design and development division.

The high power-to-weight ratio and low specific ground pressure provide fast, high manoeuvrability and mobility across difficult terrains. Low fuel consumption and fuel storage capacity of the tank optimises the operational range. The inside compartment is designed to provide high levels of comfort to the crew working over long periods. The tank also features hydro-pneumatic suspension and effective transmission system. The epicyclic train gearbox provides four forward and two reverse gears.

 

[ersakthivel]

India began trials of the new upgraded local made Arjun Mk-II MBT [Archive] - Military Photos

Some discussions in faraway forum .

 

[Damian]

The newly developed Kanchan modular composite armour gives all-round protection to the tank from anti-tank ammunition.

It is immposible to install composite armor all around tank, in such case vehicle would not only be enourmously huge, but also inacceptabely heavy, weighting probably around 100 or more metric tons.

On the other hand, I do not know to be happy or worry that some person have obsession about me, searching all my posts on all possible internet forums.

 

[ersakthivel]

It is immposible to install composite armor all around tank, in such case vehicle would not only be enourmously huge, but also inacceptabely heavy, weighting probably around 100 or more metric tons.

On the other hand, I do not know to be happy or worry that some person have obsession about me, searching all my posts on all possible internet forums.

SO THE IA WEBSITE IS WRONG PERHAPS.

YOU DIDNOT MAKE MORE THAN A COUPLE OF DUMMY POSTS.(RACIST AS USUAL) IN THE WHOLE THREAD


THE WHOLE THREAD IS A GOOD DIALOGUE ON COMPOSITE ARMOR Vs ERA ARMOR ARMOR
AND LIGHT TANK vs SMALL TANK BETWEEN AUSTIN and KUNAL BISWAS.
OFCOURSE AFTER SOME USUAL RACIST HOMILIES.

THERE WAS NO ATTEMPT TO DIVERT THE DISCUSSION INTO INANE THINGS BY MADLY QUESTIONING EVERY TERM AND FULL STOP LIKE YOU ARE DOING HERE AND NO ATTEMPT AT SHOWING OFF SOME SUPERIOR DIVINE MBT DESIGN KNOWLEDGE LIKE YOU ARE DOING HERE.

I VISIT MANY THREADS WHERE GOOD CLEAN RATIONAL DISCUSSION WITHOUT USING FOWL WORDS HAPPENS EDUCATING EVERYONE.

 

[Damian]

YOU DIDNOT MAKE MORE THAN A COUPLE OF DUMMY POSTS(RACIST AS USUAL) INT HE WHOLE THREAD.
IF I POST THEM HERE YOU WILL HANG YOUR HEAD IN SHAME.
THE WHOLE THREAD IS A GOOD DIALOGUE ON COMPOSITE ARMOR Vs ERA ARMOR ARMOR
AND LIGHT TANK vs SMALL TANK BETWEEN AUSTIN and KUNAL BISWAS.
OFCOURSE AFTER SOME USUAL RACIST HOMILIES.

Please, post them, not to mention that as usual, you do not understand nothing from my posts and their context.

I even read that thread again, no rascism there, from anyone. You have a serious mental problems.

 

[Damian]

SO THE IA WEBSITE IS WRONG PERHAPS.

Not nececary wrong, Composite armor needs a lot of space to be installed. Modern MBT's have rear and side hull armor ranging from 20mm to 80mm max, it is just immposible to place there composite armor. Same goes for turret rear, and most tanks also have max 70-80mm thick turret roof armor.

Where do you want to place composite armor that will be efficent enough?