IS-3 certainly was a very impressive tank on paper: massive firepower, very good protection and decent mobility. However, when first introduced into service it suffered teething troubles. In 1946-47 it had to be subjected to a UKN program (Fixing Construction Faults) which affected engine, gear box and hull elements. At the end of the 1950s it was subjected again to another modernization.

In combat IS-3 was quite feared by israeli crews due to front protection, which was extremely hard to overcome. However, at the end of the day better training and tactics overcame the problems.

Wouldn't it have been better to focus on the T-54/55? crews and officers seemed to be happier with these types, which were more mobile, reliable and had good firepower/protection. 100mm gun didn't have a comparable HE round but loads of money would have been saved in terms of logistics and spares.

IS-3 was available at the end of WWII, so it was a useful investment in case anything went horribly wrong somehow.

There's an article published in ARMOR (July 2002) called Red Star – White Elephant?, which shares your sentiments. It used to be available for free, but now anything after 2001 can't be accessed without an AKO password. I don't know if I have it in paper, but I'm not at my home computer now anyways. Maybe somebody else has it?

-Jon

If nothing else it scared the hell out of the West. So in the end it was worth it as the West spent big bucks trying to keep up.

Plus it was probably worth it's weight in gold as a breakthrough tank but not as an exploitation tank. It's big HE round was a formidable infantry defeating round.

99% of all tanks have teething troubles. The IS series was pushing the envelope as far as Soviet drive trains went. IMHO that is why they concentrated on medium tanks subsequently.

However, I doubt that IS-3 had many more mechanical problems than, say, Tiger I & II, and few would consider them wasted money.* The Soviets felt they needed an IS-2 upgrade; I am not really sure why, but the war was still on and there was a possibility that the West would come up with something radically new.

In any case they wanted the upgrade and they built them. One thing about teething troubles is that they can't be corrected if there are no tanks to correct them on. FTM, there was no guarantee that the mediums planned would be mechanically reliable - the first T-34s certainly had drive train problems.

The IS-3 wouldn't have to be reliable for very long, its limited ammo capacity precluded a lot of exploitation and its role was mainly as a set-piece breakthrough support tank. As it turned out all they were required to do was make it from one side of Red Square to the other on parade days.


* I am fond of harping on their considerable inadequacies, but I recognize that they did have a role - even if was as a semi-mobile pillbox.

I've heard it said before on TankNet that the JS-3 is technically a JS-2 with significant armour upgrade. The pike nose as well as heavier and far more sloped turret armour testifies to this fact.

JS-3 was also produced at a time before the heavy tank development was killed off so without the benefit of hindsight; its hard to say just if the JS-3 was "value for money" or not. Interestingly enough the JS-2 remained in service for a fair bit longer than their would-be replacement did.

I often wonder just what kind of tanks would have been designed and trialled if the heavy tank program had not been killed off?

Was the JS-3 designed to be immune to the much-feared 88mm flak gun?

The turret should be pretty resistant from all angles at long ranges, side and rear probably won't hold under ca. 1 km, front hull should be also pretty good against long 88 firing AP ammo.

At least from hastily looking on some 88 and IS-3 stats at hand.

Some like this, maybe -

This is a very interesting point as the IS-3 unreliability has never been explained in detail. According to some sources reliability was not enough for peace time, but this probably applies to loads of equipment in the 1940s.



Yes, I have read it but I don't have access any more.



The problem with IS-2 it that it's front turret armour could not be improved as it would unbalance the tank. The IS-3 design allow more armour and a better profile. In any case soviet army did consider the advantages as the T-10 was built until 1966.

The American and British responses to IS-3 were also hardly devoid of teething problems.

I was going to ask if there was a nation that DIDN'T have trouble with its heavy tank designs during the war in the early cold war.

In case the IS-3 didn't quite work out the IS-4 was put into limited production, the IS-4 being a more developed IS-2 of more conventional design.

Was replaced by the T-10M, which I think addressed many of the reliability issues

That's correct. During the WW2, nobody really cared if a tank engine would really work without breaking for 400 hours - an average life-span of a tank was lower by an order of magnitude anyway. But during the times of peace, this became a factor - a tank that needs major repairs every few months or so is too much of a burden on the military budget. So the UKN program was introduced - not to fix some "deficiencies" in the tanks, but to adapt the equipment for peace-time use.

JS-3 was the first to go through UKN simply because it's production had just started and it was not yet introduced to troops in large quantities. And it's not like JS-3 was the only tank to be subjected to UKN. After UKN program was completed for JS-3, JS-2 also underwent the very same modifications, dealing with service time, durability, reliability, crew comfort and so on. Same applies to T-34-85 and most other Soviet armour.

Still, the coincidence of the JS-3 mass-production, the end of war and the introduction of UKN program created the situation when freshly produced JS-3's were immediately sent for modifications, while JS-2's continued their service. This coincidence had created a myth about JS-3 being in some way inferior to JS-2, which is simply wrong.

Yes, but I am not too sure if this holds for IS-3. According to Mikhail Baryatinskiy the IS-3 shortcomings went all the way back to the design stages, which led to a special comission being formed to investigate problems with engine, gear box and armoured hull elements. The crash programme was applied between 1948-52 at a cost of 260000 roubles per tank. Still, IS-3 was not reliable enough, even after the upgrade

Not quite correct. Production of JS-3 started when the war wasn't yet over and tank successfully passed all government examinations. It was not until after the war that the shortcomings were discovered - but they were discovered using a totally new set of standards and requirements.

JS-2 had similar problems - but since JS-2 was considered inferior to JS-3, they subsequently had a lower priority for modifications.

There was a similar story with T-44 and T-54. Due to T-54's getting a higher priority for UKN program modifications, production of T-44's continued for about a year longer than was originally anticipated.

There's another thing to keep in mind. Tanks in general were far down the priority list after the end of the war, which significantly delayed development of new models and modification of old ones. So the direct statements ("JS-3 weaknesses took several years to fix") don't hold ground here. They weren't getting fixed because it was the time for "swords for plowshares", not because they were that hard to fix.

P. S. Baryatinsky is not the best source for tank information when it comes to technical and production issues. The myth of UKN was properly researched by M. Svirin (who recently published a trilogy on Soviet tank history), I prefer to use his books as the source material. Unlike Baryatinsky who is mostly a compiler (even if a talented one), Svirin works with original documents and archives.

Indeed, much of the data from his books can be found in www.battlefield.ru or www.armor.kiev.ua. However, the is one of the best sources in English.



This is interesting, thanks.

Harkonnen, what is the tank model in front of that pic? Obj. 416?

The IS-3 and the UKN program had its American counterpart - I mean the reliability upgrades, not the tank characteristics. The M26 Pershing was certainly a mechanical dog in 1945. Post-war the US Army went through a raft of upgrades culminating in M26A1 and finally the re-engined M46.

Some Heavy tank projects from 70-th.

An interesting article on IS-3 and its postwar use/deployment has been posted in http://otvaga2004.narod.ru/. As I cannot post the exact link, article can be found by clicking БОЕВОЕ ПРИМЕНЕНИЕ and then Боевое применение тяжелых танков ИС-3 (22.10.2008 г.). Babelfish can be used for translation. Some photos:

Direct link

Btw. Noteworthy pictures of IS-3 destroyed by catastrophic esplosion in Budapest. Saw 2 other photos of that vehicle, but those here are better.

Did the driver have his own hatch, or was all ingress/egress (including emergency bailout) through the turret?

Driver had a hatch on the triangular space at the top of the two angled front hull plates in front of the turret.

The IS/T-10 were designed to counter the super heavy Uber Panzers the Nazis were fielding late in the war. Afterward it was just bureaucratic and propaganda (ours is bigger than yours!) inertia that kept them in service. I suspect that one of the reasons the Arabs got heavies was because the Soviets were trying to get rid of them.

Used properly and with skill they could have been extremely dangerous, but they weren't and rapidly the effectiveness of their mass and firepower was undermined by gun and missile HEAT warheads that could kill them at any effective range, making them more of a logistical and mobility liability than an asset.

I continue to believe that there is more to it. The Red Army retained the heavy tank in service through c.1982, likely as an insurance policy but also because it retained a place in their tactical doctrine. Because I also believe that the 4th generation tank is a lineal descendent of the heavy, and not the MBT of the 1960s, I think they had it correct. Evidence: the M1A1 (CT) of 1992 weighed just under 70 tons; I'd wager the 70t line has since been crossed by us.

[edit to add:] re the driver's hatch, I found with the IS-III in the Littlefield Collection, I had to enter via the turret, albeit not my old svelt self of active duty days. Given the lack of turret basket, this was a lot easier route. The T-10 series added a turret basket [?], so who knows about later times.

Naw, the Russians are just packrats, and even obsolete, they are still really cool and impressive. Someone lend me $20K to go fish that one up off the coast of Cuba.

True, Zaloga assured me that he was shown T-10Ms in depot storage in the late 80s, equipped with upgraded radios, etc. He said they never threw anything away until the CFE cuts took effect.

I think the Cuban tanks swimming with the fishes would be IS-2 series, however?

I did notice the small triangular opening in front of the turret ring on what was left of the hull in the last photo. What prompted my question was the photo of the whole crew apparently heading for the turret hatches, but as Ken E. noted, that seemed to be the primary avenue of entrance and exit.

Well it is not so unusual: Leo2A4's drivers hatch is so pain in the ass to use that drivers of crews use turret hatches more often than drivers hatch also in turret position 11.40 and you can't use drivers hatch at all in turret position 06.00 due storage bin (an other reason for usage of turret hatches instead of drivers hatch might be that the drivers hatch can't be closed from outside so leaving from drivers hatch would leave hatch open and still you would had to closed it before turret can be moved). Sorry about the OT, but it just crossed my mind...

Maybe this is just semantics, but I do not think that the modern MBT is a lineal descendent of the heavy tank of WWII. I think that is a lineal descendent of the "medium-heavy" tanks of WWII (Panther, M26 Pershing, Centurion). True heavy tanks (M103, IS-3/T-10, Conqueror) were a dead end.

Similarly, an F-22 is a descendent of the P-51 and not the B-17 even though it is closer in size and weight to a B-17 than a P-51.

Strictly from a model builder's perspective, yes, the IS-III was worth every kopek!

At the development of MBT, I always viewed it as line set by medium tanks during WWII - ie it was a race to have medium tank (tactically) superior to the enemy one, leading to heavier and heavier as state-of-the-art powerplants allowed. OTOH heavy tanks were usually "overweight" re. powerpack and tended to have (atleast in design stage) specific area of employment (breakthrough).

I am well aware of the CW: Panther/Centurion/Pershing leads to LeoI/Chieftain/M60 leads to the current ones. But my research into the heavies has led me to revise my opinion, and not just to be contrarian. The thrust of the heavy projects were max firepower and armor, with mobility simply thrown away for lack of technical development of capable engines and trannies. It is the M60/Centurion/LeoI/T-62 line that comes to a dead end, because the lethality of the weapons makes their mobility worthless. The twin techno breakthoughs of special armor laminantes plus doubled and tripled power outputs of diesel and GT power packs in the 80s have the effect of promoting [or resurrecting] the heavy back into the lead. Thus, Leo II is the Tiger II, T-90 the T-10 and M1A2 the M103 but with mobility superior to the mediums, yet with unbeatable firepower and armor protection that makes K-kill increasingly problematic, even against each other.

Ken Katz, you really do not wish that I abandon the M103 work, do you????

And yet modern MBT's appeared as either:
evolutionary development of medium tanks (T-34 to T-90 or Centurion to Challenger II), when, due to the development of advanced engines and transmissions, suspensions, new armour materials and new guns medium tanks were getting tougher (and heavier) while maintaining their mobility;
or more or less fresh start (Abrams, Leclerc?);
or both (Leopard 2).
Some "concepts" (for a lack of better word) of heavy tanks had reemerged in modern MBT's, for instance modern MBT's being quite expensive and due to that they are fielded in numbers more akin to those of heavy tanks, rather than mediums.
Bot then T-90 simply can't be the T-10 of our days since they were developed for different application and with different ideas in mind (for example, for Soviet heavy tanks enemy armour was pretty much at the bottom of their target list, while T-90 ancestry can be traced back to T-62, which was initially developed as a tank destroyer). This is less true for Western armour, but there also aren't enough evidence to say that heavy tanks had more influence on MBT development, than mediums (or, if you like, that MBT's are heavies with more powerful powerpacks, rather than mediums with more armour and more powerful guns and engines or something outright new).

In case of the Leopard II, I think you are wrong. It seems plainly evident, that the development of the Leopard II started in the 1960ies with the specific purpose of developing an improved Leopard I. When the first 17 Leopard II prototypes were made in the early 1970ies, 10 carried a 105mm, 7 a 120mm and the armour seems to have been no different from the welded steel used in contemporary Leopard Is. They were also very eager to keep the weight down to about 50 tons.
Prototypes looked every bit like improved Leopard Is until 1974. It is only then, with the AV prototype that you get the incorporation of laminated armour leading the more boxy design of the Leopard II.

There is no dramatic jump in development suggesting, that thinking went from the familiar 1950ies and 60ies MBT design to something radically different, based on heavy tank designs, due to the emerging of new technology. Rather, new technology (smoothbore guns, more powerfull engines, laminated armour) was gradually incorporated in the development of a new MBT design. At least in the case of the Leopard II.

It is really no different from the medium tank in WWII growing from 20 tons to 45 tons (Pz III/IV -> Panther) while remaing a medium tank relative to lights and heavies.

Also, I dont think the case that the Panther begat the Leopard I has any merit. There was very litte, if any technological or design transfer and a WWII medium tank was a very different beast - conceptually - from the 1960ies MBT. When the Leopard I designers sat down at the drawing board in the late 1950ies, they were designing a tank for future, not patching up on some old idea from WWII.

Claus B

It is "780" tank project by ChTZ, which is crew in turret design much before the MBT-70. Though thay had the same outcome.

Object 780 has big turret bustle with parts of an autoloader in it. The model on the photo doesn't have it, although it's (pretty much) clearly related.
Also it was designed roughly at the same time as MBT-70, but it was the last known Soviet tank design with driver in turret, after Objects 416, 906B, 911B, 775 (but you obviously should know this )

If only firepower and protection defines what is a medium or a heavy
(rahter than their actual role, tactical and operational mobility and so on)
that would make the Panthers (roughly equaling the Tiger in firepower and armour)
and the T-54 (roughly equaling the IS-3 in firepower and armour) heavies,
while the M1 Abrams would be a medium as it could be penetrated frontaly
by contemporary soviet 125mm APFSDS and as it offered no improvment in firepower over the M60's
and would probably be inferior to the M103 with modern munitions.
M1A1 and M1A2 would simply be improved (more powerful gun and heavier armour) mediums, like the Centurion.

With the introduction of top attack ATGM's, all tanks should then obviously be considered as light tanks
as their armour is not even close to being considered marginal against such threats.

With the introduction of APS they then suddenly become mediums or heavies again.

A bit silly, since any tank, heavy or light, can be killed by top [or rear] attack with non-specialized weapons.
I don't know how one can distinguish heavies from mediums except in terms of firepower and protection. What is your take?
My point remains that the unconstrained effort to maximise lethality and protection in the heavies is replicated in the 4th generation
tank design method, with the added advantage that truly significant power packs - not available in the 1960s - are also available to furnish
a modicum of mobility never feasible before in heavy tank design and construction.
I am not making a case for Panther designs influencing Leo I, any more than Centurion led to Chieftain, also an independent new effort. Yet there
remains a quantum turn of events in the 1970-80 period, where the MBT designs and characteristics of the 1950-60s disappear and a newer concept
more akin to the postwar heavies, comes to the fore.
cbo, I think actually you make the case that Leo II is not an upgraded Leo I, but a new turn in capability and characteristics.

That is true. Leo2 is not upgraded Leo1. Some parts Leo2 is based on Leo1's part (for example EMES), but Leo2 is based on MBT 70 / KPZ 70 and upgraded Leo1 BOAR. Later Leo1A4's were modernized with part Leo2 FCS to become Leo1A5 (still FCS of Leo1A5 and Leo2A4 is only 80% identical). Source: Quide book of Panzermuseum Munster - Lehrsammlung Panzertruppenscule (2005)

Again, by application. Mediums being more universal (or balanced) in their design (and have a wide application), and heavies being able to take some hard fights at critical points, at the expense of mobility. What group does Abrams belong?

Unconstrained? But then why don't we see some 80-90 ton Abrams or Leopard 2 variants, that will be really protected from most current and future threats, but having a mobility only somewhat better than M103? Perhaps now it's not really needed, but if things get "hot" again in some 10-20 years, and top attack munitions and 152-mm tank guns would become widespread, wouldn't we see the reemergence of "real" heavy tanks?

Actually, I fear they are in the works, if not fielded, in case of the former. The latter, not likely.

Role? KV-1 had the same firepower as T-34 and in varant without additional armor it had also roughly the same frontal arc protection. Where it was remarkable was side and rear protection. Tiger (heavy) got roughly comparable firepower (except HE) as Panther, and Panther got better front hull armor (OTOH Tiger again got better all-round). T-10 got only marginally AP performance than T-55.

Heavies usually got better HE firepower than mediums. If judging by this, M1 is a medium, M1A1 is a Cruiser tank (with antiarmor-only gun), the same for Leopard 2...

It really depends what country you are talking about. As far as Britain is concerned you do have a point that the heavies have an influence on Challenger2. Conqueror in its armour layout very clearly influenced the development of Chieftain (as did the main armament), the difference with Chieftain in my view was to try to repackage the same kind of capability into roughly the same kind of weight class of Centurion.Its too simplistic to say that Conqueror lead immediately to Challenger2, since Conqueror was actually withdrawn from service because the 105mm gun could do everything conqueror could do in a more reliable vehicle. But I think it is fair to say that Conqueror set a gun and protection trend that was in the mind of the designers when they started putting Chieftain together. As for the 1980s, bear in mind Chieftain was field trialled in 1962, and Challenger1 (which in many respects is a warmed over Chieftain) weighed about 6 tonnes more than that.
As for the US, lets bear in mind T26 was compared to Germany and the USSR a Medium tank in the weight class, and its a bit of a stretch calling it a heavy. I have a job accepting that its possible to suggest that the 'heavy' concept lead to the Abrams, particularly as American and German tank doctrine in the 1980s looks pretty close to that of medium tanks of ww2.

As for the Soviets, I find it interesting they were moving to a 125mm gun at the same time as they were being forced to move away from heavy tanks. Looks to me like a search for the firepower of the Heavy tank, with the desire for mobility imposed by the nuclear battlefield. Modern Russian tanks clearly are not heavy tanks, or were used by them. But you can make a case they still show an influence of the later heavy tanks.

First of all, it's not exactly the same time, these events are few years apart. And then, a move towards smoothbore guns is (as thought by some to be) a result of a priority shift in tank application - defeating enemy tanks became a priority, while previously they were pretty much behind enemy infantry, fortifications etc. on the list. So you might want to phrase it like "firepower of the Heavy tank on nuclear battlefield", which is not really equal to "firepower of the Heavy tank on conventional battlefield".


Really? Thought ".eavies" are a bit back on the list behind "AIRBORNE!!! COMBAT REFORM NOW!!!"
And I was speaking about real tons, not some puny 2000 pounds, and "Heavy Abrams" being about 1.3-1.5 times heavier than M1A2SEP...
But that brings us back to the point that armor weight wasn't put on Abrams at an expense of it's mobility. And at the same time it's not like it can't be made more protected by adding more armor, but now at an expense of mobility. (or there are 2000+ hp powerpacks at work?)

A good photo of the IS-3m at Littlefield, the drivers hatch is open in this picture.

http://www.mishalov.com/littlefield-6jan07...s/img_0773.html

What year was it that it was finally decided to cancel all Heavy tank production? 1964?

I take your point about smoothbores, but I cant help but note that the balance of the rounds carried in a T64 autoloader (and for the T80 that followed it) were HE or HE Frag rounds. Not that it invalidates your point about the desire for greater AT performance, or indeed the desire to be able to say they had a bigger gun than those pesky British.

It was apparently decided to stop heavy tank development in 1959 (with Khruschev's yell being indication of that) and I think this point should be considered the end of the Soviet heavy tank. Some development might have continued beyond that, and some of the existing designs were used as a base for missile/gun-missile tanks, but none of that were ever close to deployment. Also relatively small scale T-10M production did continued until at least 1965 (with a peak of around 200 vehicles in 1960 and 61) but they were already considered to be the dead end. Such prolonged production might be related to repeated delays of long awaited next-gen medium tank, but I won't bet on that.
The first decision to design a gun more powerful than 115-mm U5-TS appeared in 1961, in 1962 a rifled counterpart was added and in 1963 smoothbore D-81 was declared to be more "perspective" (but not the winner!). During development guns were compared to each other and (on paper) with L7 and British 120-mm rifled gun. There are no mention of heavy tanks or existing large caliber guns whatsoever.
So I stand corrected, there were about 2 years between that events, but still I think the development of 125-mm guns were by no means aimed at replacing the firepower of heavies that went away, rather than the desire to outshoot "potential" enemy tanks (which is not really the same IMO)

This is per year right? Do you have data for other years?



Introduction of 125mm was rushed because of bad assessment of Chieftain armour. Soviet designers were worried that 115mm would not be enough.

Here are two more good IS-3 pics:


Shot at 2008-11-20


Shot at 2008-11-20