Arjun Main Battle Tank (MBT)

[ersakthivel]

1) ERA as it's name says is explosive reactive armor, it means that cassette have explosive filler between two steel plates (or linear shaped charges in some other designs) and when it is hit, it explodes. Modern ERA is also insensitive to small arms fire or shrapnells, so only hit by RPG's ATGM's, tank APFSDS and HEAT rounds it will explode, and only single cassette will explode at a time (only the one that is hit).

2) ERA is manufactured in 3 forms, as addons, as integral build in protection, or in modular form. Well the first generation ERA was mostly addon, the second generation like 4S22 Kontakt-5 is a build in protection mostly, the third generation is modular, of course everything depends on design.

3) Tank can't be armored by composite armor everywhere due to sieze and weight issues (well at least not yet, perhaps in future when new very strong and lightweight materials will be avaiable for mass production... these are avaiable right now, but not as a mass manufactured materials). Due to these limits ERA or addon composite armor modules, are desired way to increase protection, especially over places where base armor is weaker.

Tank warfare are grisly affairs,lasting for days with no treat like airwarefare, hails of artillery and RPG are gonna pepper any modern MBT. if each cassete explodes, Can they be called integral armour unlike the main armour which can with stand the blows? Please calrify.

 

[Damian]

Tank warfare are grisly affairs,lasting for days with no treat like airwarefare, hails of artillery and RPG are gonna pepper any modern MBT. if each cassete explodes, Can they be called integral armour unlike the main armour which can with stand the blows? Please calrify.

Oh, do I really need to explain such simple things?

ERA is a one hit armor due to it's working mechanism.
ERA can be found in different versions, from addon armor form, through modular armor form to build in integral armor form.

Several examples.

T-72B (Object 184) with 4S20 Kontakt-1 addon ERA.

T-80U (Object 219AS) with 4S22 Kontakt-5 build in (integral) ERA.

T-90MS (Object 188M) with 4S23 Relikt modular ERA.

So it can be addon, integral or modular protection. ERA is however as I said one hit armor, it means that each cassette that is hit, explodes (it is explosive reactive armor after all) and disintegrates itself. It have it's advantages like low weight and is not very bulky, but is effective protection, even very effective compared to it's weight and size. On the other hand composite armors have multi hit capabilities, but are more bulky and heavy.

ERA is good idea as a support for composite armor, and is desired to be placed where there is no composite armor (due to weight and size of composite armor, You can't place it all over the tank).

BTW: Airforces are no threat to tank units in reality, small citation:



This is from official US Armed Forces sources.

Artillery is also not big problem, especially if don't have expensive guided munitions designed to defeat AFV's. RPG's and ATGM's are based on shaped charges, and these have preatty limited capabilities to defeat modern composite armors and modern ERA, NERA and NxRA. The only really efficent way to defeat a modern tank is or top attack ATGM (if enemy tanks do not have hard kill active protection system) or a tank gun.

 

[methos]

BTW: Airforces are no threat to tank units in reality, small citation:



This is from official US Armed Forces sources.

Damian, the problem here is that a single example cannot be generalized. It is probably true that the Iraqi tank commander lost only 7 tanks to the U.S. Air Force. But this doesn't mean that all tank units lost only a small percentage of their tanks to air-strikes, it means this specific unit lost only a few tanks. I have watched a Gulf War documentary once - there a single A-10 took out five tanks (with what appeared to be real footage from the Gulf War) - does that mean that all A-10s destoryed 5 tanks each? No. The M1 is not credited for having made more tank kills than the M2/M3 by U.S. sources.

 

[Damian]

Damian, the problem here is that a single example cannot be generalized. It is probably true that the Iraqi tank commander lost only 7 tanks to the U.S. Air Force. But this doesn't mean that all tank units lost only a small percentage of their tanks to air-strikes, it means this specific unit lost only a few tanks. I have watched a Gulf War documentary once - there a single A-10 took out five tanks (with what appeared to be real footage from the Gulf War) - does that mean that all A-10s destoryed 5 tanks each? No. The M1 is not credited for having made more tank kills than the M2/M3 by U.S. sources.

Many other realiable sources, also from USA, says that effecitveness of USAF was low, and the initial reports was a pure fantasy of "flyboys".
I didn't say that M1's had more kills than M2/M3's.

 

[Damian]

Damian, the problem here is that a single example cannot be generalized. It is probably true that the Iraqi tank commander lost only 7 tanks to the U.S. Air Force. But this doesn't mean that all tank units lost only a small percentage of their tanks to air-strikes, it means this specific unit lost only a few tanks. I have watched a Gulf War documentary once - there a single A-10 took out five tanks (with what appeared to be real footage from the Gulf War) - does that mean that all A-10s destoryed 5 tanks each? No. The M1 is not credited for having made more tank kills than the M2/M3 by U.S. sources.

Many other realiable sources, also from USA, says that effecitveness of USAF was low, and the initial reports was a pure fantasy of "flyboys".
I didn't say that M1's had more kills than M2/M3's.

 

[ersakthivel]

Oh, do I really need to explain such simple things?

ERA is a one hit armor due to it's working mechanism.
ERA can be found in different versions, from addon armor form, through modular armor form to build in integral armor form.

Several examples.

T-72B (Object 184) with 4S20 Kontakt-1 addon ERA.

T-80U (Object 219AS) with 4S22 Kontakt-5 build in (integral) ERA.

T-90MS (Object 188M) with 4S23 Relikt modular ERA.

So it can be addon, integral or modular protection. ERA is however as I said one hit armor, it means that each cassette that is hit, explodes (it is explosive reactive armor after all) and disintegrates itself. It have it's advantages like low weight and is not very bulky, but is effective protection, even very effective compared to it's weight and size. On the other hand composite armors have multi hit capabilities, but are more bulky and heavy.

ERA is good idea as a support for composite armor, and is desired to be placed where there is no composite armor (due to weight and size of composite armor, You can't place it all over the tank).

BTW: Airforces are no threat to tank units in reality, small citation:



This is from official US Armed Forces sources.

Artillery is also not big problem, especially if don't have expensive guided munitions designed to defeat AFV's. RPG's and ATGM's are based on shaped charges, and these have preatty limited capabilities to defeat modern composite armors and modern ERA, NERA and NxRA. The only really efficent way to defeat a modern tank is or top attack ATGM (if enemy tanks do not have hard kill active protection system) or a tank gun.

I pretty much know what you have said.But ARJUN weight comes from it's bulky composite armour that can withstand multi hit capability,which Indian army doesn't want,while all major western armies prefer it.

Indian army says the lesser composite armoured T-90 with ERA can have the same protection. So it supports T-90 over arjun.In tank warfare there can be no upper limit for number of hits on a tank. So if guided munition artilery and RPG hits continue wont the ERA give off in an hour or two?

Then without the protection of a multi hit resistant composite armour how can the tank survive?

I used air war analogy only to indicate it's limited engagement time, And fighters can flee from the scene using speed. But tanks cant.They have to stand and fight.SO do you think it is right for army to ignore the higher weight multi hit resistant ARJUN armour ?

I'm afraid that what happened to IRAQI tanks after they faced ABRAMS will happen to indian army if it continues to reject better protected multi hit resistant bulky arjun ,in favour of less bulky less armour protected ,ERA relying T-72s and T-90s.

 

[Damian]

I pretty much know what you have said.But ARJUN weight comes from it's bulky composite armour that can withstand multi hit capability,which Indian army doesn't want,while all major western armies prefer it.

It depends on philosophy. Also remember that Soviet tanks also have composite armor over hull and turret front, however, it is less bulky (less thickness) than in western MBT's. But as I said, it is a matter of philosophy.

Indian army says the lesser composite armoured T-90 with ERA can have the same protection. So it supports T-90 over arjun.In tank warfare there can be no upper limit for number of hits on a tank. So if guided munition artilery and RPG hits continue wont the ERA give off in an hour or two?

Try to hit manouvering tanks several times, and in the same won't being hit by them. So no, ERA won't deplet on a single tank after hour or two.

Then without the protection of a multi hit resistant composite armour how can the tank survive?

Because it actually have a composite armor over hull and turret front?

I used air war analogy only to indicate it's limited engagement time, And fighters can flee from the scene using speed. But tanks cant.They have to stand and fight.SO do you think it is right for army to ignore the higher weight multi hit resistant ARJUN armour ?

What I know, is that besides armor, there is also economy and logistics, Arjun is more expensive, it is heavier, bigger. Indian Army have to choose, or existing infrastructure that supports T-72M1 and T-90S, or Arjun that is not supported by these valid points. Of course this does not mean Arjun should not be purchased, but the question is what should be ratio between Arjun and T-90S.

I'm afraid that what happened to IRAQI tanks after they faced ABRAMS will happen to indian army if it continues to reject better protected multi hit resistant bulky arjun ,in favour of less bulky less armour protected ,ERA relying T-72s and T-90s.

And I afraid You are making too fast conclusions. How do You know that Arjun is better protected than T-90S? Actually Arjun Mk1 in many points is inferior to T-90S. I also didn't heard that Arjun's Kanchan armor is similiar to the current generation composite armors in NATO tanks, it does not use for example heavy metal alloys, neither I heard about advanced armor steel types like HHS, DHS or THS, it might be there, or might be not.

So making such fast conclusions is not very... justified.

Also You should remember that to improve protection, Arjun Mk2 will use the exactly same 4S22 Kontakt-5 ERA as T-90S.

Conclusions might be that Army made comparision tests between the two, and Kanchan alone on the Arjun was less effective than Kanchan + 4S22 Kontakt-5 on T-90S.

You must understand that different types of armor offers different protection levels. So for example if M1A2SEP v2 composite armor offers similiar or better protection than T-90S armor, it does not mean that Arjun Mk1 with Kanchan armor will offer the same protection level as American tank, only because both do not have ERA installed.

The whole issue is very complex, more than You probably imagine, especially that most of composite armors still are classified designs, and not much is known about them, sometimes nothing.

 

[Kunal Biswas]

Got some info on Arjun will post soon..

 

[Kunal Biswas]

2008 Arjun MCS

 

[ersakthivel]

It depends on philosophy. Also remember that Soviet tanks also have composite armor over hull and turret front, however, it is less bulky (less thickness) than in western MBT's. But as I said, it is a matter of philosophy.



Try to hit manouvering tanks several times, and in the same won't being hit by them. So no, ERA won't deplet on a single tank after hour or two.



Because it actually have a composite armor over hull and turret front?



What I know, is that besides armor, there is also economy and logistics, Arjun is more expensive, it is heavier, bigger. Indian Army have to choose, or existing infrastructure that supports T-72M1 and T-90S, or Arjun that is not supported by these valid points. Of course this does not mean Arjun should not be purchased, but the question is what should be ratio between Arjun and T-90S.



And I afraid You are making too fast conclusions. How do You know that Arjun is better protected than T-90S? Actually Arjun Mk1 in many points is inferior to T-90S. I also didn't heard that Arjun's Kanchan armor is similiar to the current generation composite armors in NATO tanks, it does not use for example heavy metal alloys, neither I heard about advanced armor steel types like HHS, DHS or THS, it might be there, or might be not.

So making such fast conclusions is not very... justified.

Also You should remember that to improve protection, Arjun Mk2 will use the exactly same 4S22 Kontakt-5 ERA as T-90S.

Conclusions might be that Army made comparision tests between the two, and Kanchan alone on the Arjun was less effective than Kanchan + 4S22 Kontakt-5 on T-90S.

You must understand that different types of armor offers different protection levels. So for example if M1A2SEP v2 composite armor offers similiar or better protection than T-90S armor, it does not mean that Arjun Mk1 with Kanchan armor will offer the same protection level as American tank, only because both do not have ERA installed.

The whole issue is very complex, more than You probably imagine, especially that most of composite armors still are classified designs, and not much is known about them, sometimes nothing.

According to the latest trials ARJUN out scored T-90 in every parameter,whether shhoting on the move accurately or better armour protection.Arjun withstood several hits from T-90 without being compromised.While same is not the case for T-90.This is according to senior army officers who were present in the trials,and it is reported in this thread too.

1.The weight of arjun is due to the heavier armour protection and nothing else.

2.The engine and transmission are not the cause of weight.Better shell seperation,blow off panels,bulkier heavy armour protection are the reason for this weight all according to the same philosophy of western tanks like M1A1 abrams and LECLERC.

3.This is the point that is consistently ignored when discussing arjun,s weihgt issue.

4.Also how heavier western tanks cope with terrain all over the world?

5.The gulf war was the demonstration of western armour vs soviet armour.That's why harping on the infrastructure issues seem to be not prudent.

6.ALso during the war will the enemy leave 50 ton bridges undestroyed to let the enemy in?

7.Since ground pressure excerted per square inch by arjun is lesss than T-172 and same as T-90 there seems to be no terrain issues on arjun.

AS ARJUN crossed RAVI river at LASSIAN which was previously marked as non tankable by indian army operating T-72 there are no ground pressure issues on arjun,it seems

Please post your replies.
Thanks.

 

[Kunal Biswas]

Some corrections :

In trails Arjun preformed equally good as T-90S but better in Shooting during night trails as per Generals..

Arjun turret weights 20-25ton, Rest is of chassis..

The present Arjun blow off panels are not very useful as on M1A2 coz Ammo are not in isolated containers, Only Arjun MK2 have isolated containers at turret..

Arjun MK1 ground pressure is better than T-90S as well as T-72..

 

[ersakthivel]

Some corrections :

In trails Arjun preformed equally good as T-90S but better in Shooting during night trails as per Generals..

Arjun turret weights 20-25ton, Rest is of chassis..

The present Arjun blow off panels are not very useful as on M1A2 coz Ammo are not in isolated containers, Only Arjun MK2 have isolated containers at turret..

Arjun MK1 ground pressure is better than T-90S as well as T-72..

Did they say in particular anything about the strength of the armour of ARJUN and T-90? It is widely reported in many blogs that ARJUN withstood point blank range hits from T-90 without any problem?

But same is not the case with T-90.

Do you have any clarification in this regard?

Please present your point of view on the weight of ARJUn.Is it there for better protection of the crew and tank? or due to inefficient engineering as reported widely in the indian media.

DOesn't the increased armour protection of ARJUn is not so important in hunter killer mode in the vaunted "COLD START doctrine" as all other western tanks have similar weight and protection level.

Since as damian said that ERA cassettes are one hit affair , then after repeated hits wont they give way and expose the armour ,especially in tomorrow's war precision guided munition will hit relentlessly .

Since ARJUN crossed the RAVI at LASSIAN which was marked non tankable in indian army map(equiped with T-72), The weight of arjun which is well spread out with lesser pressure per sq inch wont hamper it's deployment in any terrain where T-72s T-90s can be deployed.

So it is the bridge issue alone that is holding up the ARJUN.Please post your thoughts whether retreating PAK army in any future war will allow T-90 crossable 50 ton weight bridge intact?That seems highly impossible since they can't count on US support anymore so the territory they lose will be hard to get back in any future negotiations.
So will they leave the bridges intact as repeatedly reported by media according to senior army officers?

Also from the world war days 50 ton + weastern tanks have operated through out the AFRICAN continent ,europe and middle east and even in asia in vietnam and korea. WHERE there any 60 + ton bridges there? how did they manage this weight issue. Please post your thoughts.

Thanks.

 

[Kunal Biswas]

Point black range against T-72M1 not T-90S, Most Importantly it was shot with a Russian Ammo and Second was with Israeli, Arjun withstand both..

This is the time when the Russian Tank T-72 imported by Indian Army could not penetrate the Kanchan Armor protected Arjun Tank , with APFDS at point blank range. Subsequently, the debate took place if the Russians had supplied us with training rounds rather than the actual ammunition. As a side note, in January 2000 at Proof & Experimental Establishment (PXE), Balasore, Arjun tank armor defeated all available HESH and FSAPDS rounds including Israeli FSAPDS rounds.

Read more: The Kanchan Armor - Frontier India - News, Analysis, Opinion - Frontier India - News, Analysis, Opinion

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

T-90S too tested against modern ammo extensively without ERA and passed

Weight is not an serious issue, as from my personal experience in these areas, Same applies for T-90S/72M1..

Without a doubt Arjun can be good start in cold doctrine, But due to insufficient number it cannot be added..

Damian is correct, Even in past enemy tanks are hit repeatedly where they hit before it increase chances of killing it faster..

The reality is very different than what Indian media is publishing or even people at MOD, People who spend there time in north-west India would know that the bridges so call 50ton cannot even hold 30ton sometime cannot even hold 20ton, In this sense one have to prepare tanks for fording and deploy assault bridges, Here T-72/90 face same issues as Arjun MK1/2..

 

[Damian]

1.The weight of arjun is due to the heavier armour protection and nothing else.

You have not even a smallest idea about tanks then. Arjun bigger weight do not comes from more armor, it comes from pure size of vehicle and size of it's components.

2.The engine and transmission are not the cause of weight.Better shell seperation,blow off panels,bulkier heavy armour protection are the reason for this weight all according to the same philosophy of western tanks like M1A1 abrams and LECLERC.

compare the weight of Arjun powerpack and powerpack of T-90S, You might be surprised.

Also Arjun is not designed per western designing philosophy, it is a completely false belive of people that never done any proper analizys of it's design. In fact Arjun have more commonalities in terms of armor protection placement with T-90S than with Leclerc or M1A2.

3.This is the point that is consistently ignored when discussing arjun,s weihgt issue.

Generally the lower is weight, the better it is. Of course it is not so easy to explain, and unfortunetly, You expect easy, even more than simplified explanations. Which is not good, world is not simple, neither it's understanding should be simplified.

4.Also how heavier western tanks cope with terrain all over the world?

Depending on terrain and crews, but overall there are no significant problems.

5.The gulf war was the demonstration of western armour vs soviet armour.That's why harping on the infrastructure issues seem to be not prudent.

No, You are making the most basic mistake here. Iraqis were using obsolete, downgraded export tanks, with inferior protection, inferior FCS... well they didn't had even real FCS, inferior ammunition, everything there was inferior to what soviets had.

 

[Hari Sud]

Hello Kunal, Damian and Ersakthivel;

All of you cool it. You have good points, but arguing amongst yourself is of no help. Indian Army would soon come out soon on its own findings of this summer trials. We have to wait until that.

If Indian Army does not want Arjun in large numbers then you can do nothing about it. It is them who are going to be at the tip of the spear. It is their preference which would count.

Indian Army for the last two decades has been complaining about Indian made hardware; only because it is Indian. They want super perfect hardware and imported seems to be their best choice. Take for example Arjun tank case; any army in the world would welcome a tank like this, but not the Indian Army. Or the case of INSAS RIFLE. They wish to get the imported interchangeable barrel rifle at four times the price of locally made INSAS. The forgoing after all THE bugs of INSAS HAVE BEEN WORKED OUT IN LAST TEN YEARS. Remember F- 16 it took 20 years modifications to reach the current level of performance. The list goes on and on.

Hence my three well informed friends, would you please cool it. Arjun would be used by the army. Good or bad their preference matters the most.

 

[Kunal Biswas]

The Whole tank Layout from Inside out is very much Leo2a4 influenced..

Some of the points are different as per Army GSQR, other than that its western layout tank..

Also Arjun is not designed per western designing philosophy, it is a completely false belive of people that never done any proper analizys of it's design. In fact Arjun have more commonalities in terms of armor protection placement with T-90S than with Leclerc or M1A2. .

 

[ersakthivel]

You have not even a smallest idea about tanks then. Arjun bigger weight do not comes from more armor, it comes from pure size of vehicle and size of it's components.



compare the weight of Arjun powerpack and powerpack of T-90S, You might be surprised.

Also Arjun is not designed per western designing philosophy, it is a completely false belive of people that never done any proper analizys of it's design. In fact Arjun have more commonalities in terms of armor protection placement with T-90S than with Leclerc or M1A2.



Generally the lower is weight, the better it is. Of course it is not so easy to explain, and unfortunetly, You expect easy, even more than simplified explanations. Which is not good, world is not simple, neither it's understanding should be simplified.



Depending on terrain and crews, but overall there are no significant problems.



No, You are making the most basic mistake here. Iraqis were using obsolete, downgraded export tanks, with inferior protection, inferior FCS... well they didn't had even real FCS, inferior ammunition, everything there was inferior to what soviets had.

If the excess weight of ARJUN doesn't come form heavier armour all around, then from where does the weight comes.It is marginaly bigger than T-90 not a third bigger to have more weight.

Damian whole world knows what is the philososphy behind ARJUN. Impressed by the performance of heavier challenger tanks and shell shocked by the PATTEN fiasco in longovala, fearing that americans will supply heavier tanks to PAk,the Design philosophy of arjun was modelled on the heavier western tanks.

That's why it's design is based on the german LEOPARD.IF you say otherwise,Then I dont know what to say.Please google and check the history behind arjun development. The T-72 makers were not invited for the tech help for arjun.It is the makers of german leopard who gave design info.That's why it has RENK power pack.

I have the comprehension to understand all the complex stuff in the world. If you want to check me out you can go to ADA TEJAS thread in this forum and read all the 300 posts. My comprehension is as good as that.

I do follow many sources on the web,and I have knowledge too. SO you don't have to dismiss me for lacking knowledge about tanks.

I have seen pictures of blown up T-72 s that cannot withstand crude anti tank mines planted by the LTTE in srilanka.

I have also seen many pictures in the net in the latest skrimishes near the russian border where T series tanks were blown up, turret apart.

The Iraqis may not have good FCs.But it is the armour of T series tanks that couldn't hold up against ABRAMS.Not the other way around.

I know very well what ERA is .It is a secondary armour only.It can never substitute for a good kanchan armour

I know very well about the KANCHAN armour's superiority.

So If you cannot explain,you don't have to respond with stuff like "You don't know anything about tank design " stuff.

World over knowledge about tank warfare is common. And world over tanks are always heavier the better.

Generally the lower is weight, the better it is. Of course it is not so easy to explain, and unfortunetly, You expect easy, even more than simplified explanations. Which is not good, world is not simple, neither it's understanding should be simplified

Tell me how many western MBTs follow this philosophy. WHy are leclarc,abrams,leopard all are in the arjun weight class?
Doon't they all know the efficient weight techniques of T series?Whether you are fortunate or unfortunate is not the issue here.

SO rolling along with UPGRADED T-72s while criticizing ARJUN will back fire on Indian army one day.

 

[ersakthivel]

Also the russian BLACK EAGLE weighs 50plus tons compared to arjun's 55 tons. So not very dissimilr I think.Please correct me If I am wrong.The arjun's redesigned turret in Mk-II version results in a weight of 55 ton ,reduced from 58.5 tons for Mk-I.Is this correct?

 

[methos]

If the excess weight of ARJUN doesn't come form heavier armour all around, then from where does the weight comes.It is marginaly bigger than T-90 not a third bigger to have more weight.

It is not "marginal bigger". It's turret has probably more than twice the volume of the T-90's turret, while the hull is more than 1 meter longer.

That's why it's design is based on the german LEOPARD.IF you say otherwise,Then I dont know what to say.Please google and check the history behind arjun development. The T-72 makers were not invited for the tech help for arjun.It is the makers of german leopard who gave design info.That's why it has RENK power pack.

There are no Indian nor German sources indicating that the Indians cooperated with the Germans. The Leopard 2 might have been an influence, but there was no cooperation, especially not with KMW, as KMW back then didn't even exist. The Renk transmission and MTU engine were adopted after the indigenous engine and transmission failed to met required performance.

The Iraqis may not have good FCs.But it is the armour of T series tanks that couldn't hold up against ABRAMS.Not the other way around.

The Iraqis had T-72s, T-72Ms and T-72M1s. The largest part of their T-72 force had armour designed prior 1974, with only the T-72M1s having somewhat modern armor from 1978/79. That this armour could not resists M829 APFSDS (DOI 1985/86) and M829A1 APFSDS (DOI 1989/1990) is nothing special.

I know very well about the KANCHAN armour's superiority.

Kunal said that the T-90 also survived firing trials without ERA. So much about the superiority of Kanchan.

 

[navkapu]

It is not "marginal bigger". It's turret has probably more than twice the volume of the T-90's turret, while the hull is more than 1 meter longer.



There are no Indian nor German sources indicating that the Indians cooperated with the Germans. The Leopard 2 might have been an influence, but there was no cooperation, especially not with KMW, as KMW back then didn't even exist. The Renk transmission and MTU engine were adopted after the indigenous engine and transmission failed to met required performance.



The Iraqis had T-72s, T-72Ms and T-72M1s. The largest part of their T-72 force had armour designed prior 1974, with only the T-72M1s having somewhat modern armor from 1978/79. That this armour could not resists M829 APFSDS (DOI 1985/86) and M829A1 APFSDS (DOI 1989/1990) is nothing special.



Kunal said that the T-90 also survived firing trials without ERA. So much about the superiority of Kanchan.

T-90 also survived firing trials without ERA? Did it? i don't recall was the hit point blank?