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Russian Tanks: Helium Armor?


Poopstain

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These 'K' versions existed once in the battalion and once in the regiment. The external difference was an approximately 2.5 meter long tube that was attached to the side of the turret (on the T-55AK). In the tube there was a 10 m telescopic mast for the stationary operation of a short-wave radio. In some T-54 or T-55 versions, the tube can be confused with the snorkel for underwater driving. The company commander had two radios for VHF, but only one antenna for both. Platoon leader had only one radio.

T-55AK:

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I'm with Bojan, the overall size reduction does help with not getting seen/not getting hit, just not very much so under less than ideal situations; in the pre-computerized tank gunnery age certainly more so than later. And it seems like the advantages aren't large enough to offset certain compromises in other areas, depending on how important you rate them. Modularity is great for field repairs and probably worth ending up with a tank that may be 5...10cm taller because of it, unless you simply don't care all that much for field repair.

The Armata is as tall as contemporary western designs, but it does away with internal crew space in the turret and therefore has only armor protection of the gun assembly against medium caliber rounds. Nevertheless, if you want high crew protection at minimal weight cost, the concept is solid - put them all into an enlargened driver's space low in the hull, behind some massive steel wall.

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14 minutes ago, Ssnake said:

I'm with Bojan, the overall size reduction does help with not getting seen/not getting hit, just not very much so under less than ideal situations; in the pre-computerized tank gunnery age certainly more so than later. And it seems like the advantages aren't large enough to offset certain compromises in other areas, depending on how important you rate them. Modularity is great for field repairs and probably worth ending up with a tank that may be 5...10cm taller because of it, unless you simply don't care all that much for field repair.

The Armata is as tall as contemporary western designs, but it does away with internal crew space in the turret and therefore has only armor protection of the gun assembly against medium caliber rounds. Nevertheless, if you want high crew protection at minimal weight cost, the concept is solid - put them all into an enlargened driver's space low in the hull, behind some massive steel wall.

"Modularity" concept is completely unrelated to the silhouette. T-80, for example, has a powerpack unlike the T-64/72. It's simply a matter of the details in how the couplings are designed.

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26 minutes ago, sunday said:

There is a major drawback in a low silhouette for a tank - lesser gun depression, so less ability to fight in reverse slopes.

Yes partially, but not necessarily. M1 is not particularly tall with 244cm, and yet it has -9 deg. Yugoslav M-636D prototype was only 5cm higher than T-54/55 and had -8 deg depression with the same 100mm gun. There are probably more examples. Soviets just did not consider large gun depression thing that they really needed, hence they have never particularly bothered with it.

Re. modularity, there are modular power packs for T-55 (and T-72) available, with minimal changes to the tank hull. So it could have been done in the tank of T-55 size, just none bothered at the time.

KoDnx3m.jpg

Edited by bojan
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All assemblies individually also has advantages. It's not that fast, okay. But in field conditions where everything and everyone is lacking, even the experienced crew can do a lot on their own with technical assistance. And how many power packs does a battalion have in stock? The ice gets thin very quickly.

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To add on to what bojan said, a RENK powerpack is used in PT-91M, and it occupies the same volume as the original T-72 engine compartment.

With regard to turret height, gun depression is actually not the deciding factor. In many NATO tanks, the commander sits on top of the turret ring, rather than inside it. This is responsible for much of the turret height. Eliminating this is what allowed the Leopard 1 to have a shorter turret than M60A1 and Chieftain at no cost to gun depression. The Abrams design also moved the TC into the turret ring, which allowed the turret height to be reduced. Again, at no cost to gun depression.

Generally speaking, in cases where the commander is seated on top of the turret ring, the turret ceiling is significantly taller than is actually necessary for maximum depression (inclusive of the recoil guard and clearance for case ejection). This excess height is partly necessary due to the fact that the loader needs clearance room behind the breech to reach up with a fresh cartridge and load it. However, this is easily solved by implementing an indexing angle in the gun safety circuit, where the gun automatically resets to a specific loading angle that's more convenient to the loader after it fires, and then returns to the aiming point controlled by the gunner when the loader hits his safety switch. This is available in Leo 2 and Abrams, but it was already used as early as the T-10, T-55 and T-62.

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Negative elevation is probably a bit overrated. Has this really turned out to be an eminent disadvantage? (how does the terrain have to be designed in order to get real (!) added value from it?)

I put more value on a fast reverse gear. Observing with the Peri. Then sprint forward, fire and quickly dodge.  

Edited by Stefan Kotsch
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10 hours ago, Interlinked said:

With regard to turret height, gun depression is actually not the deciding factor. In many NATO tanks, the commander sits on top of the turret ring, rather than inside it. This is responsible for much of the turret height. Eliminating this is what allowed the Leopard 1 to have a shorter turret than M60A1 and Chieftain at no cost to gun depression. The Abrams design also moved the TC into the turret ring, which allowed the turret height to be reduced. Again, at no cost to gun depression.

The TC of the M60A1 is inside the turret ring.

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6 hours ago, Tim Sielbeck said:

The TC of the M60A1 is inside the turret ring.

It's like in T-34-85, where technically the seat itself is inside the turret ring (but only when fully lowered), but the commander does not fit within the turret ring itself, even when the seat is fully lowered. His body is totally above the turret ring, such that his head is well within the tall cupola. 

Edited by Interlinked
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On 1/15/2022 at 5:57 AM, bojan said:

Does a smaller tank leads to the shorter sweep range when using battlesight?

Is a smaller tank easier to "hide" in the field?

Does a smaller tank means that ranging errors will have greater effect?

We could argue how much this benefits smaller tank, but to say there are no benefits would ignore a fact that everyone did try to make them as small as possible for some reason. Even M1 is less tall than M60, and that was one of the requirements in it's design.

There is obviously an advantage beyond concealment etc. from small size in that the protection is far better for a given mass. If the T-55 was instead on M-60 proportions, but constrained to be the same mass (and therefore similar mobility for the same power plant etc.) it's amour would need to be considerably thinner.

One could argue that with good HEAT rounds everywhere this mattered less, as typical large bore HEAT rounds had no trouble penetrating, but in actual practice everyone still used a lot of AP and there were lots of more marginal threats still around. And even if one accepts this argument, one could reduce armor to protection against light AT weapons only and get a substantially lighter and somewhat cheaper tank.

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1 hour ago, Interlinked said:

It's like in T-34-85, where technically the seat itself is inside the turret ring (but only when fully lowered), but the commander does not fit within the turret ring itself, even when the seat is fully lowered. His body is totally above the turret ring, such that his head is well within the tall cupola. 

The TC's seat goes straight up and straight down.  It has a spring-loaded pole mounted inside the turret ring and the seat hinges off of this inside the turret ring.  It doesn't swivel side to side or move front to back.  It does fold the back down so the TC can stand on it to better see with his head outside of the cupola without stepping on the padded seat.  It also can fold the seat up so the gunner can get into his position more easily and the TC can stand on his footrest for easier movement between the rangefinder and the .50 cal. sights.  Having used one many time myself it fits inside the turret ring quite nicely at all heights.  The cupola's opening is directly above the seat and there is no need to move over the turret ring to access it.

Edited by Tim Sielbeck
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1 hour ago, Tim Sielbeck said:

The TC's seat goes straight up and straight down.  It has a spring-loaded pole mounted inside the turret ring and the seat hinges off of this inside the turret ring.  It doesn't swivel side to side or move front to back.  It does fold the back down so the TC can stand on it to better see with his head outside of the cupola without stepping on the padded seat.  It also can fold the seat up so the gunner can get into his position more easily and the TC can stand on his footrest for easier movement between the rangefinder and the .50 cal. sights.  Having used one many time myself it fits inside the turret ring quite nicely at all heights.  The cupola's opening is directly above the seat and there is no need to move over the turret ring to access it.

Perhaps I wasn't clear enough to get across the concept -

In the M60A1, the pole for the TC's seat has a fixed height, the seat is mounted to it on a telescoping rod. The seat cannot be lowered below the pole, so the seat cannot physically be lowered below the turret ring. At its lowest height, the seat is around the same level of the turret ring ("inside" the turret ring). Though the seat base is technically within the turret ring's diameter when fully lowered, the commander, seated on this cushion, has his torso entirely above the level of the turret ring and there would not be enough back clearance for his body to fit properly into the turret ring's diameter, if the seat was hypothetically lowered below the turret ring. His backrest is in the turret bustle at such a distance that the TC's back sticks out beyond the turret ring diameter. Compare this to a T-54/55, where the TC's seat is far below the turret ring, is around 15-20cm forward of the turret ring, and his backrest is fitted on the turret ring snag guard itself. In this case, the commander's torso is entirely within the turret ring, not above it. 

t-55+turret+seats.png

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Edited by Interlinked
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21 hours ago, Stefan Kotsch said:

Negative elevation is probably a bit overrated. Has this really turned out to be an eminent disadvantage? (how does the terrain have to be designed in order to get real (!) added value from it?)

I put more value on a fast reverse gear. Observing with the Peri. Then sprint forward, fire and quickly dodge.  

I think it had significant disadvantage to Syrians in battles of Golan Heights. At least according to interviews of Israeli tankers made for Youtube stuff about those battles. Syrians coming over the hill had to drive fully over the crest to engage Israeli Centurions waiting them below, because they could not depress their guns enough.

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1 hour ago, Sardaukar said:

I think it had significant disadvantage to Syrians in battles of Golan Heights. At least according to interviews of Israeli tankers made for Youtube stuff about those battles. Syrians coming over the hill had to drive fully over the crest to engage Israeli Centurions waiting them below, because they could not depress their guns enough.

That's probably a case of very poor maneuvering. It is generally a bad idea to drive over the crest of a hill in general, let alone to engage an enemy that is already waiting for you. Even if the hill was shallow enough that a tank could peek over the top with -9 to -10 degrees of gun depression, and the tanks are positioned for a hasty defence (letting the enemy come to them), it is not a recommended practice.

q1LsV7m.png

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But did the Syrians really have any options? They were the ones attacking, they had to close with the enemy and do it quickly before the Israelis had time to reinforce the units guarding the border. There might not be that many ways around those crests and the Syrians could not afford to be picky if that would cost them to much in time, better to lose more tanks but win the war.

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6 minutes ago, wendist said:

But did the Syrians really have any options? They were the ones attacking, they had to close with the enemy and do it quickly before the Israelis had time to reinforce the units guarding the border. There might not be that many ways around those crests and the Syrians could not afford to be picky if that would cost them to much in time, better to lose more tanks but win the war.

The point of that video is not the tactical constraints imposed by the terrain of the Golan battlefield, but the usefulness of gun depression in tanks.

Edited by sunday
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I'm in full agreement with you there and it's likely that the Syrians would have done better if their tanks did have the ability to depress the gun more. My response was more directed towards Interlinked's post, that the Syrians were not necessarily  stupid or poorly trained when they decided to go over those crests, they just simply did not have any other options.

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5 minutes ago, wendist said:

I'm in full agreement with you there and it's likely that the Syrians would have done better if their tanks did have the ability to depress the gun more. My response was more directed towards Interlinked's post, that the Syrians were not necessarily  stupid or poorly trained when they decided to go over those crests, they just simply did not have any other options.

Then, we agree.

Still, attacking upslope in those conditions looks like a losing proposition. Perhaps some artillery could have done a number on the defending Cents, but the defensive positions were well concealed.

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Well, I don't think that example is a textbook case of gun depression being critical, because in this case, the Centurions obtained a hull-down position behind natural berms with the concealment of tall wild grass. They only backed up behind a reverse slope to get into a turret defilade position. 

On the Syrian side - if they were obliged to attack over open ground, then having more gun depression wouldn't have mattered, because they were obliged to drive over open ground rather than attempt to hit the Centurions from positions on the crest of the hill. Whether it was even possible to take up positions on the crest of the hill is another matter, because it looks like quite a tall hill. Since they were obliged to attack, ideally, they should have fanned out into some type of attack formation and sought covered positions of their own in that field rather than continue marching in a single file on the road, apparently paralyzed with indecision. But, of course, this is all assuming that the scene in the film is completely true to life!

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On 1/15/2022 at 3:56 AM, Stefan Kotsch said:

Negative elevation is probably a bit overrated. Has this really turned out to be an eminent disadvantage? (how does the terrain have to be designed in order to get real (!) added value from it?)

I put more value on a fast reverse gear. Observing with the Peri. Then sprint forward, fire and quickly dodge.  

Isn't "negative elevation" a quality more closely associated with a defensive mindset?   If your doctrine is that you are going to be swamping your enemy charging ahead in inexorable "waves," what good is negative elevation going to do you?

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