T-90 Main Battle Tank

Present transmissions seen working into any T-72 and T-90 model are not fully automatic, it is proven by the fact they cannot rotate around their central axis with a track rolling forward and the other rolling backwards.

Really?

You think that?

A T-34 has control sticks... forward to go forward and back to slow down or go backwards.

One stick for each track.

Gears for higher speeds.

When sitting still a T-34 driver can push one stick forward and one stick back and do what you suggest you need an automatic transmission for...

Manual clutch and manual gearbox in T-34.

By itself, rotating around the central axis sounds as it could be just a stunt, but it speaks about the capabilities of the transmission to manage power variations and wrong manouveurs by the pilot, in this way relieving him from a lot of workload.

Yes... of course... because if he turns too hard and gets the angle of rotation wrong he has to stop the vehicle.... get out... make sure all the tires are fully pumped up and then get back in and start up the engine and... no he does not... if he turns too hard he might cut a corner and run over a car or smash into a building... which is not really that big a deal.

BTW what if the driver is a super dooper western tank also makes a mistake.... how the fuck does this transmission detect whether he has turned too sharply or not sharply enough, or has done it just right... how does he know what manouver was intended? Does it read his mind or is it in the manual?

Driving a tank in a battle, it is just too easy to ask a transmission too much in terms of braking, reversing or turning, up to the point to stop abruptly the tank altogether.

Most transmissions are built around the engine and the weight of the tank, but having said that transmissions break down occasionally to think otherwise is to be naive. The drivers do get training and learn what they can do and what they can't, and what they should or should not do.

An advanced, fully automated transmission, will apply any input just up to the maximum extent it could manage, superseding any input potentially dangerous.

Really... I thought it just changed gears.

T-72 and T-90 present engines are quite powerful, but far from being all that dependable, to the point that in peace time they are downrated to prevent too much tear and failures, again it has to be rectified with an engine able to provide all the full power for all of its standard life expectancy.

F-16 pilots are g limited during training to maximise the life span of the air frame, engines in tanks are not... these engines are designed to be used at the rated level... to save engine life they will use tank simulators more and more but in the mean time they take older model tanks out for drives...

If the standard for a tank engine should be like 50,000 running hours before total overhaul and rebuild, than it has to work at full settings for 50,000 hours, with no compromise being acceptable.

So without knowing anything about the new engines fitted to the upgraded T-72 and the T-90AM you are saying their engines are crap?

Please provide all the evidence for these accusations or in future I will refer to you as May.

About APFSDS, together with the alloy properties and its molecular structure, penetrator length is the real performance defining factor.

A given thickness will limit length, because a very long narrow rod will flex and any flex would be fatal to penetration performance because it would fold like a bent nail and not penetrate at all.

So, given as defined the alloy used for the penetrator, and given as defined the building process with the resulting internal molecular structure, the only real way to boost penetration capabilities is to design longer penetrators.

Length means weight concentrated on a small point, which is good, but as I said too much and everything goes real bad real fast.

A longer penetrator is heavier but the material it is made of and its construction is just as important as its length... if not more so.

Even boosts in speed are of limited usefulness, without an appropriate increment in penetrator's length.

If that were true then why aren't APFSDS penetrators that are 3m long the standard?

The Sprut towed gun of the Soviet and Russian Army could have a penetrator of any length you like...

You could equally say that the longer the barrel the better the penetration and performance of all rounds will be... so where are the 20m long tank gun barrels?

At the end of the day extreme length would be more of a problem than any sort of solution.

Guns seem to be around 6-8m long for tanks... they could make them longer but they would keep bumping them into things and damaging them... besides a long gun is a heavier gun... it is the same with ammo.

I read some of your other posts and it's become clear to me that dozens of exploding HEAT and HE shells cannot be held back by rather thin "blast-proof" doors. The "blast-proof" doors on the M1A2 Abrams are apparently only 10cm thick.

There is no such thing as blast proof... just like there is no such thing as bullet proof...

These are blast resistant doors into the crew area (a sliding door so the loader can get ammo but kept closed in case the ammo area is hit and so the blast does not enter the crew compartment). The blow out panels are designed to prevent enemy fire entering the ammo compartment but are design to blow out if there is an internal explosion. This compromised design is intended to stop an enemy using an anti material rifle to shoot your main gun ammo and set it on fire to destroy the tank, but also if an enemy ATGMs like Konkurs hits the side of the tank and penetrates and ignites the ammo that the ammo will blow up and through the blow out panels and not through the blast door into the crew compartment.

10cm is 100mm which is more than the frontal armour on a T-34.

I understand that a turret bustle is more exposed to enemy fire but it also increases the offensive qualities of the tank through the use of longer rounds.

I agree, and with fluid binary propellent then the risk of putting APFSDS rounds in the turret bustle is eliminated because with just penetrator rods and no propellent there would be no risk of fire... just the chance of some damaged rounds.

Does the binary liquid propellant set-up reduce the chances of explosion or does it completely remove the possibility of that event? I presume that this binary liquid design enables the 62 rounds in the rear turret autoloader to consume the same space as 31 rounds.

There are three risks of secondary explosion in a tank... fuel, HE and HEAT warheads in rounds and missiles, and propellent.

The biggest risk is propellent because it is very easy to set off... just a spark will do it. In comparison most modern explosives need an explosion to detonate them... if you set them on fire they will burn but that is all.

Fuel needs to be heated to a flashpoint before it will explode... which is rather hot and with diesel it will need to burn for several minutes to achieve that...

A Konkurs hit directly to a HE warhead will detonate it and its detonation would probably set off other HE and HEAT rounds near is so there is always the risk of explosion... the risk of it hitting fuel and setting it off in an explosion big enough to destroy the vehicle is rather low IMHO.

Binary liquid fuel systems would make a tank a hard nut to crack...

The T-90AM could certainly serve as a test-bed for systems in the T-14 Armata and would greatly benefit from the incorporation of advanced systems like the Afghanit APS. If the T-90AM essentially became roboticized, would it not be vulnerable to hacking - just like the drones currently in use?

Encrypted datalinks could be used, but you would have to monitor the battlefield for enemy EM signals and any platforms directing signals at your robots should be priority targets...

but an APS is absolutely essential.

I agree, but against most current threats ARENA-2 should be fine... keep afghansi a secret... the sooner information about it spreads the sooner it will need an upgrade...

Underfloor blow-out panels would not stop exploding HEAT and HE rounds from piercing up into the crew compartment, so I now see the folly of underfloor blow-out panels - especially in the age of asymmetric warfare. I

I suspect the logic is that any underfloor explosion that penetrates the floor armour will kill the crew anyway... so by putting the autoloader there it is first of all unlikely to get hit and secondly if it is hit the crew would likely have been killed anyway...

Thanks again for taking the time to answer the flurry of questions I directed your way. respekt

No worries.

Actually I often find questions about things I know interesting, because it makes me think more about how the things I knew about work and why they work the way they do...

No, I do not think that.

It is so.

Show me a russian tank able to rotate in the spot.

If there is no russisn tank able to do so, try to see why.

Modern transmissions provide an automatic torque management and distribution, managing not only to brake and at last to stop the internal track to perform a turn, they can also revert track's rotation, all the while managing torque distribution so to not break its own gears or to trigger a failsafe disconnection by the clutch.

The ability of rotate on the spot is more than a mere performance: it's a marker of transmission management capabilities of extreme running requirements.

Those capabilities give a tank driver a more forgiving vehicle to manage, greatly reducing the chances of a wrong manoveur leading to a forced stop of the tank.

It is still possible to perform a mistake, just far less likely.

About APFSDS, designing and building penetrators with great L/D ratios is all but easy.

The slightest inperfection would result in the flechette breaking apart at the moment of inpact.

Still, the quest for longer penetrators is the main course adipted by any tank guns' designer, in the west just like in Russia.

T-72 and T-90 are limited by their internal geometry, and offer little to no room for further improvements.

Western tanks, with turrets offering far greater internal room, still have margins for further improvements in ammunitions employed and in some cases even in the gun themselves, being potentially able to adopt the future Rheinmetall's 130 mm gun.

Unless they decide to rip out the internal autoloader and replace it with a turret bustle that carries the ammo like was planned for black eagle. So there is rather room for upgrade.

A d under manual transmission (which I prefer over automatic just because of maintenance reason alone), you can still rotate the vehicle while still.

But whatever

miketheterrible wrote:Unless they decide to rip out the internal autoloader and replace it with a turret bustle that carries the ammo like was planned for black eagle.  So there is rather room for upgrade.

A d under manual transmission (which I prefer over automatic just because of maintenance reason alone), you can still rotate the vehicle while still.

But whatever

I think what he means to say is that the upgrade would be a drop-in feature in some Western tanks, where it would require replacing the entire turret for a T-90 or a T-72. The argument thus beeing that Western tanks would be upgraded faster and more effeciently than the same number of Russian tanks.

He can correct me if i misunderstood.

0nillie0 wrote:

miketheterrible wrote:Unless they decide to rip out the internal autoloader and replace it with a turret bustle that carries the ammo like was planned for black eagle.  So there is rather room for upgrade.

A d under manual transmission (which I prefer over automatic just because of maintenance reason alone), you can still rotate the vehicle while still.

But whatever

I think what he means to say is that the upgrade would be a drop-in feature in some Western tanks, where it would require replacing the entire turret for a T-90 or a T-72. The argument thus beeing that Western tanks would be upgraded faster and more effeciently than the same number of Russian tanks.

He can correct me if i misunderstood.

There is a solution its called the T-14 Armata and they are already producing it.

0nillie0 wrote:

miketheterrible wrote:Unless they decide to rip out the internal autoloader and replace it with a turret bustle that carries the ammo like was planned for black eagle.  So there is rather room for upgrade.

A d under manual transmission (which I prefer over automatic just because of maintenance reason alone), you can still rotate the vehicle while still.

But whatever

I think what he means to say is that the upgrade would be a drop-in feature in some Western tanks, where it would require replacing the entire turret for a T-90 or a T-72. The argument thus beeing that Western tanks would be upgraded faster and more effeciently than the same number of Russian tanks.

He can correct me if i misunderstood.

Yeah, when one doesn't have an auto loader, I guess it would be easier to install larger rounds. Here's the thing though, the man in the tank has to be quick to load it. While as the downside is that the autoloader is limited, that's true. But in both cases, if US wants to improve it's tank, adding in an autoloader would be extremely expensive and time consuming. Or they add one into the turret bustle but that would also require heavy work or new turret. T-90 can easily get a new turret and can also be done same way, as well as keeping current turret.

Thank you wholeheartedly to both 0nillie0 and miketheterrible, you both scored what I'm trying to say.

About moving the autoloader to an external bustle, it has been tried with the Chorny Oriol concept: while the concept in itself seems to be sound, both T-72 and T-80 hulls have limits about turret's weights distribution: the Chorny Oriol prototype had an external bustles hosting the ammunitions without any meaningful armor in order to not move too backward the turret's center of gravity.

So the-thing-next-door is absolutely right, IMHO: the right answer is to build Armata's, that are designed from day one to overcome all of the constraints that have hampered T-72s and T-80s families' developments.

My opinion is the even if lethality against MBTs and crew's protection have little room left for further improvements, the T-72 family still has a wonderful potential as a mechanized infantry tool at very little costs.

A 125 HEAT or Frag-HE shell has just nothing wrong in itself, airburst or any kind of new special ammunition could be easily developed from models born for any similar gun, passive protection would always be far better than any basic or uparmored IFV.

So I think it would still takea while before seeing the T72 and T-90 fading away, but they will give up, as long as is possible, to T-14s the task of stopping enemy's armored spearheads or to force enemy's lines to make abreakthrough, abd will become the swiss knife of mechanized infantry, providing them with direct fire support, tank-destroying capabilities and recon-by-force.

Show me a russian tank able to rotate in the spot.

If there is no russisn tank able to do so, try to see why.

You can turn a tank on the spot by running one track forward or backward and keeping the other track still... any tracked vehicle can do it.

The ability of rotate on the spot is more than a mere performance: it's a marker of transmission management capabilities of extreme running requirements.

Russian and Soviet tanks can turn on the spot.

Those capabilities give a tank driver a more forgiving vehicle to manage, greatly reducing the chances of a wrong manoveur leading to a forced stop of the tank.

You could also argue that having a gear stick lever shaped like a penis makes non gender specific western tankers much excited about their work in a tank, but I really don't see why you are talking about such garbage.

Ohh, I suspect the transmission in the new Abrams can cook bacon and eggs and clean the plates afterwards, while a damn backward Russian tank wont even heat the coffee...

It is still possible to perform a mistake, just far less likely.

How?

How does it know what is or is not a mistake and how does it prevent it?

The slightest inperfection would result in the flechette breaking apart at the moment of inpact.

Bullshit... you could cut grooves down its entire length and that would do nothing to effect penetration, there could be dozens of imperfections in the thing and it would still penetrate.

T-72 and T-90 are limited by their internal geometry, and offer little to no room for further improvements.

Every tank is limited by their internal geometry and there is little or no room to change them either...  

Western tanks, with turrets offering far greater internal room, still have margins for further improvements in ammunitions employed and in some cases even in the gun themselves, being potentially able to adopt the future Rheinmetall's 130 mm gun.

Yeah, of course, they can take Javelins in their turrets no problem because their loaders can perform magic tricks to manouver those 3 metre long penetrators in those one piece rounds from a rear storage bin and into the gun breach no problems...

About moving the autoloader to an external bustle, it has been tried with the Chorny Oriol concept: while the concept in itself seems to be sound

Tested and rejected... ammo stored in a turret bustle was deemed too exposed to enemy fire to be useful if joined to the crew compartment... hense there is ammo storage in the T-90MS and Armata turret bustle but it is not connected to the crew compartment.

both T-72 and T-80 hulls have limits about turret's weights distribution: the Chorny Oriol prototype had an external bustles hosting the ammunitions without any meaningful armor in order to not move too backward the turret's center of gravity.

Geez you do make shit up... the gun hanging off the front of the turret and the heavy frontal armour would actually benefit from a balancing rear turret bustle.

The reason they don't do it is because the rear turret is horribly vulnerable and not a good place to put live ammo.

Makes you wonder why the US military bothered for all those years with the M60 with its crappy old 105mm gun... I mean the richest country on the planet still using that old crap when they were building Abrams tanks... you'd think they lived in the real world where even an M60 might actually be over kill in some cases and was not a good idea to throw everything out because they can't run their tracks in different directions at once.

BTW please list all the western tanks that can perform this... I would be interested in seeing it, but to be honest the value of such a trick is close to zero.

The T-90MS already has a rapid turret turn rate and with one track stationary and the other running it could turn even more rapidly to engage a target... complicating the transmission to allow one track to run forward and the other to run back just sounds pointless and complicated... can your car do that?

My car has an automatic transmission... do you think if I turned the wheel really hard the wheels on one side of my car will go forward and the wheels on the other side will go backwards?

Turning around a braked track is in no way comparable to turn around the center axis with one track rolling forward and the other rolling reverse.

If somebody could not see the difference, let it be it, but the difference is just huge.

A modern, automatic transmission is able to manage torque distribution, up to the point to just transmitting downward the gears' chain as much torque as the gears' chain can adsorbe without breaking.

If 90% of modern AFVs in the world, former soviet ones as well, are using or are upgraded with ZF or Renk's transmissions is not because they are fancy: it is just because they are years or even decades ahead of anything else available, and they make far far easier to drive an AFV whatever it is.

About APFSDS, it is just I said: L/D diameters are dictated by technological capabilities on forming internal crytalline's structure.

It doesn't mean if the penetrator has grooves or whatever included. What means is the core, i.e. the central rod, to be able to withstand the impact without breaking apart.

As I said, in APFSDS' penetration is accomplished by one way only: through reciprocal ablative process between the penetrator and the armour.

As soon a penetrator has no longer enough mass left, meaning mass included in its solid crystalline structure, penetration stop for good.

Any following fragments just do not count anything more: either the penetrator keep its monolithic structure intact through the whole penetration's process or it falls way short of its theoretical penetration's performances.

It is just Physics, none's opinion would ever change it.

Penetrators' length, far before practical management inside an AFV's turret, is dictated by technological capabilities.

As of today, the most extreme L/D attainable are between 32:1 up to 40:1, give or take, and it is dictated by the capability to make them without meaningful defects in their internal molecular structure.

Just to circumvent technological's limitations concepts as segmented rods and telescopic rods have been tried around the world, until today with little success in the real world's application.

Still, those experiments are a veritable testament of the fact that you could not increase at will L/D ratios because of the inability to grant consistent structural soundness.

If you look at the inside of any, I mean any western MBT, be it Abrams, Leopard 2 or Challenger, or even K1, and then you compare the available room with a T-72, T-80 or T-90 turret, the amount of free space, plus the inherent flexibility of manual loading becomes just trivial to recognize.

An autoloader is a wonderful thing, but it could not be adapted to manage ammunitions far greater than it was designed to, while a human loading a gun by hand could easily manage any round until there is room left in the turret and the round's weight is manageable by a human being.

It is also a fact, whatever people would like to believe.

Peŕrier wrote:Turning around a braked track is in no way comparable to turn around the center axis with one track rolling forward and the other rolling reverse.

If somebody could not see the difference, let it be it, but the difference is just huge.

A modern, automatic transmission is able to manage torque distribution, up to the point to just transmitting downward the gears' chain as much torque as the gears' chain can adsorbe without breaking.

If 90% of modern AFVs in the world, former soviet ones as well, are using or are upgraded with ZF or Renk's transmissions is not because they are fancy: it is just because they are years or even decades ahead of anything else available, and they make far far easier to drive an AFV whatever it is.

About APFSDS,  it is just I said: L/D diameters are dictated by technological capabilities on forming internal crytalline's structure.

It doesn't mean if the penetrator has grooves or whatever included. What means is the core, i.e. the central rod, to be able to withstand the impact without breaking apart.

As I said, in APFSDS' penetration is accomplished by one way only: through reciprocal ablative process between the penetrator and the armour.

As soon a penetrator has no longer enough mass left, meaning mass included in its solid crystalline structure, penetration stop for good.

Any following fragments just do not count anything more: either the penetrator keep its monolithic structure intact through the whole penetration's process or it falls way short of its theoretical penetration's performances.

It is just Physics, none's opinion would ever change it.

Penetrators' length, far before practical management inside an AFV's turret, is dictated by technological capabilities.

As of today, the most extreme L/D attainable are between 32:1 up to 40:1, give or take, and it is dictated by the capability to make them without meaningful defects in their internal molecular structure.

Just to circumvent technological's limitations concepts as segmented rods and telescopic rods have been tried around the world, until today with little success in the real world's application.

Still, those experiments are a veritable testament of the fact that you could not increase at will L/D ratios because of the inability to grant consistent structural soundness.

If you look at the inside of any, I mean any western MBT, be it Abrams, Leopard 2 or Challenger, or even K1, and then you compare the available room with a T-72, T-80 or T-90 turret, the amount of free space, plus the inherent flexibility of manual loading becomes just trivial to recognize.

An autoloader is a wonderful thing, but it could not be adapted to manage ammunitions far greater than it was designed to, while a human loading a gun by hand could easily manage any round until there is room left in the turret and the round's weight is manageable by a human being.

It is also a fact, whatever people would like to believe.

You do realise that in order to substantially increase the lenth of the pentrator you will need not only a new autoloader but also a new gun as the increased weight of your ultra long penetrator will mean that either you cannot fire it at a high enough velocity and it will just snap off on the surface of your targets armor or your gun will simply explode.

Also not to mention the limits imposed by the strenth of your materials I highly doubt that it is possible to make a 2 or 3 meter long APFSDS round that has a penetrator with a diameter of under 80mm.

Anyway why even bother with 3 meter APFSDS when you cound just have a 305mm or 406mm HE shell.

Nobody,but you and GarryB, have ever spoke of three meter long APFSDS flechettes.

By the way, until now both the Rheinmetall 120 mm and the soviet/russian 2A46 have experienced over the years great increases in chamber's maximum pressures, but both have clearly reached or very close to their design limits.

Turning around a braked track is in no way comparable to turn around the center axis with one track rolling forward and the other rolling reverse.

If somebody could not see the difference, let it be it, but the difference is just huge.

Yes, the difference is enormous... to perform the circus act of turning around a stationary point you need to spend a small fortune on an expensive and complicated transmission.

As shown in this video a T-90MS can turn practically on the spot with a much simpler. much cheaper, much more reliable transmission:



From about 35 seconds into the video it shows the vehicle turning on the spot perfectly fine...

If 90% of modern AFVs in the world, former soviet ones as well, are using or are upgraded with ZF or Renk's transmissions is not because they are fancy: it is just because they are years or even decades ahead of anything else available, and they make far far easier to drive an AFV whatever it is.

Reducing the reliability and increasing the maintainence issues and potential problems with a transmission is not an upgrade.

About APFSDS, it is just I said: L/D diameters are dictated by technological capabilities on forming internal crytalline's structure.

What you said is length is everything and everybody would make them as long as they could... but they don't.

It doesn't mean if the penetrator has grooves or whatever included. What means is the core, i.e. the central rod, to be able to withstand the impact without breaking apart.

You said if they weren't perfect they would not penetrate... I am basically saying that is bullshit... nothing mass produced is perfect.

As I said, in APFSDS' penetration is accomplished by one way only: through reciprocal ablative process between the penetrator and the armour.

You are wrong.

There were plenty of old penetrators the Russians used including on their early 115mm rounds for the T-62 that used tungsten core penetrators with a plain steel sheath. The sharp tip was just for aerodynamics because an angled plate would shear off a sharp tip anyway so a semi blunt tip was more effective in starting a penetration at any angle of impact.

Any following fragments just do not count anything more: either the penetrator keep its monolithic structure intact through the whole penetration's process or it falls way short of its theoretical penetration's performances.

You might want to tell that to western designers because there were more than a few making multiple section penetrator cores because they knew the ERA the Russians produced post cold war sheared off penetrators... one solution they looked at was segmented penetrators...

It is just Physics, none's opinion would ever change it.

Yeah, you educate them dumb Ruskies about physics... I mean what would they know...

Penetrators' length, far before practical management inside an AFV's turret, is dictated by technological capabilities.

Of course... extra long penetrators can only be made in the west because you need technology to make them and Russia has no technology.

As of today, the most extreme L/D attainable are between 32:1 up to 40:1, give or take, and it is dictated by the capability to make them without meaningful defects in their internal molecular structure.

So each penetrator is scanned to a molecular level... is that when they beam them down from the Enterprise?

It is funny you say that because Soviet and Russian penetrators are generally rather thicker than western penetrator rods... which suggests if there is an LD ratio limit then the Russians will be able to make longer rods than the west...

Just to circumvent technological's limitations concepts as segmented rods and telescopic rods have been tried around the world, until today with little success in the real world's application.

Bullshit. Segmented rods are to get around being guillotined by ERA panels...

If you look at the inside of any, I mean any western MBT, be it Abrams, Leopard 2 or Challenger, or even K1, and then you compare the available room with a T-72, T-80 or T-90 turret, the amount of free space, plus the inherent flexibility of manual loading becomes just trivial to recognize.

Yes, obviously, when you look inside an 9 person people mover and see all that space and then look inside a mini and see the limited space you might be moved into thinking that big bus of a 9 person mover is better... until people start shooting at you and you realise sitting in a big target is not a good idea... lots of room in an Abrams is not so special and is only there so the loader has a chance to do his job... the superior Soviet/Russian do away with the human loader for a reason... well for several reasons... a 40 ton tank with similar protection levels to a 69 ton tank... the gunner and commander don't need to load the gun so the extra room to allow them to do so would just make the turret a bigger heavier target.

An autoloader is a wonderful thing, but it could not be adapted to manage ammunitions far greater than it was designed to, while a human loading a gun by hand could easily manage any round until there is room left in the turret and the round's weight is manageable by a human being.

You would have a point if the larger turret space of the Abrams allowed much longer penetrators than the T-90... but it does not.

By the way, until now both the Rheinmetall 120 mm and the soviet/russian 2A46 have experienced over the years great increases in chamber's maximum pressures, but both have clearly reached or very close to their design limits.

Which begs the question, if length of penetrator is so damn critical why waste time getting higher pressure when they should be developing longer rod penetrators?

One could argue if making them longer is so technologically difficult then it makes no sense to waste time and money trying to do so... just make them thicker.... that increases weight too.

And by the way... the new Afghanistan APS system works by inducing yaw in an incoming threat... longer thinner penetrator rods would be vastly more vulnerable to being rendered ineffective by yaw than a shorter thicker rod... though both would seriously lose penetration.

Ok, I give up.

How thick could the *blast-resistant* doors be if the T-90AM did get a bustle autoloader? It's apparently 100mm (10cm) thick in the M1A2.

Depends what you mean.

The T-90s underfloor auto loader is loaded by the gunner kneeling on his seat with the shield that separates him from the gun mechanism raised... the driver gets the rounds out of the wooden boxes the ammo comes in and hands them to the commander standing on the hull next to the turret and hands the rounds into the turret for the gunner to place them into the autoloader position. The procedure includes pressing buttons so the autoloader knows what types of rounds are being put in each autoloader position so that in combat when the gunner selects the type of ammo to load the computer knows where the nearest round of that type is stored in the autoloader... rotates to that position and loads it.

The propellent stubs are made of cardboard and are not that strong so they must be carefully handled and are enormous fire risks... so no smoking...

The point is that if you add a turret bustle autoloader I would actually add proper fire walls to separate the crew from all the ammo with no opening for manual handling of the ammo... when you are sitting on the seats with the hatches closed you would not be able to turn 180 degrees back and then reach down below the floor or into the turret bustle for the 20kg rounds to manually load them into the gun which is about 30cm behind your back when sitting forward.

By separating the gun breach area and ammo from the crew compartment, you would not need to slowly access the positions in the autoloader to load them... you could have heavy doors on top of the turret bustle autoloader and load 22 rounds and propellent stubs in there and push a button and use the autoloader to move the rounds from the bustle autoloader to the underfloor autoloader... preferably the HEAT rounds and the HEFRAG rounds, with the turret bustle reserved for the APFSDS rounds and perhaps missile rounds that could be longer. Once the rounds had transfered to the underfloor loader and it was full then the remaining rounds put in the bustle would then have the tank fully loaded... the commander could sit in the commanders position and push the buttons and the driver and gunner could load the ammo and propellent stubs.

On the Abrams there is a sliding door between the troop compartment and the turret bustle with the ammo... if it is 100mm thick then it would be a pain in the ass to move on ground that is not totally level and it would weigh quite a lot.

If you are referring to the roof armour with the blow out panels their design is a compromise... it needs to be thick enough to stop rounds from above penetrating and igniting the ammo, but it also needs to be light enough to get blown out easily before internal pressure turns it from burning propellent to near exploding propellent.

It is basically like a relief valve... you don't want it open all the time, but when put under pressure it is supposed to fail to allow the release of pressure so nothing worse happens.

The sliding door does not need to be super strong... it just needs to hold up against the pressure, while the blow out panels fail and allow the pressure to fall to safe levels again.

Having said that if the turret bustle contains HEAT rounds and HE FRAG rounds and the threat is a Konkurs ATGM that hits the rear bustle and penetrates the warheads of one or more HEAT or HE FRAG warheads and they detonate then blast panels and blow out doors mean nothing... all the ammo and the propellent will explode and not much will be left.

That is why the Russians want their ammo stored under heavier armour that the turret bustle has on its sides and rear.

GarryB wrote:Depends what you mean.

The T-90s underfloor auto loader is loaded by the gunner kneeling on his seat with the shield that separates him from the gun mechanism raised... the driver gets the rounds out of the wooden boxes the ammo comes in and hands them to the commander standing on the hull next to the turret and hands the rounds into the turret for the gunner to place them into the autoloader position. The procedure includes pressing buttons so the autoloader knows what types of rounds are being put in each autoloader position so that in combat when the gunner selects the type of ammo to load the computer knows where the nearest round of that type is stored in the autoloader... rotates to that position and loads it.

The propellent stubs are made of cardboard and are not that strong so they must be carefully handled and are enormous fire risks... so no smoking...

The point is that if you add a turret bustle autoloader I would actually add proper fire walls to separate the crew from all the ammo with no opening for manual handling of the ammo... when you are sitting on the seats with the hatches closed you would not be able to turn 180 degrees back and then reach down below the floor or into the turret bustle for the 20kg rounds to manually load them into the gun which is about 30cm behind your back when sitting forward.

By separating the gun breach area and ammo from the crew compartment, you would not need to slowly access the positions in the autoloader to load them... you could have heavy doors on top of the turret bustle autoloader and load 22 rounds and propellent stubs in there and push a button and use the autoloader to move the rounds from the bustle autoloader to the underfloor autoloader... preferably the HEAT rounds and the HEFRAG rounds, with the turret bustle reserved for the APFSDS rounds and perhaps missile rounds that could be longer. Once the rounds had transfered to the underfloor loader and it was full then the remaining rounds put in the bustle would then have the tank fully loaded... the commander could sit in the commanders position and push the buttons and the driver and gunner could load the ammo and propellent stubs.

On the Abrams there is a sliding door between the troop compartment and the turret bustle with the ammo... if it is 100mm thick then it would be a pain in the ass to move on ground that is not totally level and it would weigh quite a lot.

If you are referring to the roof armour with the blow out panels their design is a compromise... it needs to be thick enough to stop rounds from above penetrating and igniting the ammo, but it also needs to be light enough to get blown out easily before internal pressure turns it from burning propellent to near exploding propellent.

It is basically like a relief valve... you don't want it open all the time, but when put under pressure it is supposed to fail to allow the release of pressure so nothing worse happens.

The sliding door does not need to be super strong... it just needs to hold up against the pressure, while the blow out panels fail and allow the pressure to fall to safe levels again.

Having said that if the turret bustle contains HEAT rounds and HE FRAG rounds and the threat is a Konkurs ATGM that hits the rear bustle and penetrates the warheads of one or more HEAT or HE FRAG warheads and they detonate then blast panels and blow out doors mean nothing... all the ammo and the propellent will explode and not much will be left.

That is why the Russians want their ammo stored under heavier armour that the turret bustle has on its sides and rear.

Thanks a million for this incredibly educational post, mate. I had no idea that propellant stubs were made of cardboard. That's somewhat disconcerting.

I really do like the idea of creating a mechanism that would transfer ammunition from the bustle autoloader to the underfloor autoloader, and if this was employed in tandem with the other brilliant idea you spoke off -> binary-liquid propellant... it would significantly increase battle persistence and would be exceptionally safer than other tanks - except for the T-14.

My comment about the 10cm thick doors was in reference to the sliding blast doors of the M1A2 Abrams. I understand now that these *blast-resistant doors are only really effective in re-directing propellant explosion away from the crew compartment and would fail against HE-FRAG and HEAT explosions. I observed an exchange between you and Damian, and the man was adament that blast-doors could contain HE-FRAG and HEAT detonations.

I agree with you about the need to put HE-FRAG and HEAT rounds in the underfloor autoloader while storing the longer, more powerful sabot rounds in the bustle autoloader; it would mean that turret blow-off panels would only have to contend with propellant explosions-- unless binary-liquid propellant was used.

Like you said, the underfloor autoloader in the T-90 is much harder to hit and is under armour - so it's actually safer; the inclusion of binary-liquid propellant would remove the chances of propellant explosions - leaving only HE-FRAG and HEAT detonation being the only (un-avoidable) danger... a danger only addressed by the T-14.

Blow-out panels wouldn't work against HE-FRAG and HEAT detonation in the M1A2, and so I no longer advocate for it for the underfloor autoloader... but another one of your posts piqued my interest:

Garry B wrote:   BTW blow out panels don't have to face upwards... it could have downward facing blow out panels below it to direct any explosion out of the vehicle. It actually wouldn't be that hard to design panels that are pressure and penetration resistant in one direction and blow out panels in another direction.

This could probably work for small HE-FRAG and HEAT detonations. Am I wrong here? What are your thoughts on 'insensitive' munitions? How effectively would they reduce catastrophic explosions in HE-FRAG and HEAT rounds?

Thanks a million for this incredibly educational post, mate. I had no idea that propellant stubs were made of cardboard. That's somewhat disconcerting.

To be clear the actual rear propellant stubs that are ejected on firing are made of metal... the material that contains the propellant in front of the metal stub is propellant impregnated cardboard that is completely consumed during firing leaving nothing but the small metal stub to eject.

My comment about the 10cm thick doors was in reference to the sliding blast doors of the M1A2 Abrams. I understand now that these *blast-resistant doors are only really effective in re-directing propellant explosion away from the crew compartment and would fail against HE-FRAG and HEAT explosions. I observed an exchange between you and Damian, and the man was adament that blast-doors could contain HE-FRAG and HEAT detonations.

This could probably work for small HE-FRAG and HEAT detonations. Am I wrong here? What are your thoughts on 'insensitive' munitions? How effectively would they reduce catastrophic explosions in HE-FRAG and HEAT rounds?

What we are talking about with blow out doors is a pressure release system to prevent the pressure reaching to high levels where they are much more dangerous.

If we are talking about HEAT and HE detonations then there is no talk of pressure reduction as HE explodes supersonically and reaches peak pressure too fast to contain or release.

Most HE material is insensitive in the sense that you could set it on fire and it would just burn harmlessly... it only detonates with a detonator... in other words it takes a small explosion to make it explode.

However material that is insensitive, does not make it less explosive... or less powerful.

RDX is an explosive... and often has a mixture of wax... usually about 6% wax to stop it exploding unexpectedly... for explosives to work they need a very vigorous fuel that burns rapidly and spontaneously, but it also needs chemicals that react rapidly and generate enormous amounts of oxygen for the fuel to burn supersonically.... and because of this (ie making their own oxygen) they will explode in space or under water.

does anyone know what how much protection is provided by the T-90As turret (without ERA)?

Aslo the frontal turret armor seems to get thinner the closer it is to the gun mantlet.

Some 500mm RHA.

Hole wrote:Some 500mm RHA.

That sounds off for a tank that wasn't made in the early 1980s.

On the images I have seen it looks a lot thicker than the hull.

Doesn't the hull provide 600mm RHAE?

Hole wrote:Some 500mm RHA.

Nope, from tests made in 1999 even a rpg-7vr could not penetrate the tank without ERA. Only one Kornet penetrated the t-90 without ERA.

http://fofanov.armor.kiev.ua/Tanks/TRIALS/19991020.html

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YG_AJ wrote:

Nope, from tests made in 1999 even a rpg-7vr could not penetrate the tank without ERA. Only one Kornet penetrated the t-90 without ERA.

http://fofanov.armor.kiev.ua/Tanks/TRIALS/19991020.html

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This is about APFSDS not HEAT.

T-90
Basic armor 530 mm (APFSDS), 520 mm (HEAT)
Kontakt 5 (!) 250 to 280 mm (APFSDS), 500 to 700 mm (HEAT)

Source: Soviet/Russian armor and artillery design practices 1945 to the present

T90A
turret front 830 mm (APFSDS), 1350 mm (HEAT)
hull front 800 mm (APFSDS), 1150 mm (HEAT)

Source: Tanks of the USSR & Russia since 1945

Hole wrote:T-90
Basic armor 530 mm (APFSDS), 520 mm (HEAT)
Kontakt 5 (!) 250 to 280 mm (APFSDS), 500 to 700 mm (HEAT)

Source: Soviet/Russian armor and artillery design practices 1945 to the present

T90A
turret front 830 mm (APFSDS), 1350 mm (HEAT)
hull front 800 mm (APFSDS), 1150 mm (HEAT)

Source: Tanks of the USSR & Russia since 1945

There's no way that the T-90A has 800mm RHAE on the hull UFP the thicker part of the turret maybe but certainly not the hull.