American Prototype Light Tanks Post-WWII Part 3: The T71, T92, and the M551

Author: Priory_of_Sion

To finish off my other two articles about Postwar American Prototype Lights I will discuss the T71, T92, and the XM551.

The T71 and the T92 originated from the US Ordnance Committee in 1952, by 1953 they had chosen 3 designs. They were the T71 by Detroit Arsenal, the T71 by Cadillac, and the T92 by AAI.

Detroit's T71 was an 18 ton vehicle with an oscillating turret and an 76 mm autoloader(same ballistically to the M41's 76 mm gun). With ~340 hp it would be fairly quick. The frontal armor was a pike design similar to the IS-3.

Cadillac's T71 was a conventional style tank without an autoloader. It used the same gun as the Bulldog. It was to weigh a little less than 18 tons and would have the same engine as the other T71. Both T71s lost out to the T92 due to rapid progress in the T92's development. 

In WoT the hull is from the Cadillac T71 while the turret is from Detroit. If I recall correctly, The_Chieftain has alerted Minsk of their folly. In a future patch expect the T71 turret to be reunited with its hull.

The T92 is a very unique design which emphasized smallness. Weighing a little over 18 tons and armed with the same 76 mm gun the T92 was very close to being put into production which was planned in 1962. The 375 hp engine of the T92 would allow it to be very mobile. The 76 mm gun was located in a cleft turret which allowed for -10 degrees of comfy depression. The T92 was equipped with a semiautomatic loader. This would fire 1 round at a time and did not have any sort of drum. Each round would be put into the semiautomatic loader one at a time. After the round is fire the shell is automatically ejected. Protection is effectively the same as the M41 but lighter weight materials such as aluminum were used to protect parts of the T92.

This is the semiautomatic loader.

T92 size compared to the M41.

Some people say that UFOs are actually flying T92s from another dimension.

The first T92 arrived at Aberdeen in 1956, the second arrived the next year. Both proved capable machines but there were problems found, in all 50 changes were to take place and ranged from problems with the tracks to problems with the shell case ejector. In 1957, before the 2nd pilot T92 arrived at Aberdeen, Congress found out about Soviet PT-76 and its amphibious capabilities. The T92 was unable be modified to become amphibious due to the design of the vehicle. In 1958 the T92 was cancelled.

The XM551 was to be born out of the ashes of these 1950s prototypes. In 1959 requirements for an Armored Reconnaissance/Airborne Assault Vehicle(AR/AAV) were set, is was to be amphibious, air mobile, to have greater firepower than the M41, and to be quick. AAI and Cadillac presented thier designs. AAI's  12.5 ton AR/AAV featured a 3 man crew with a 152 mm gun-launcher. The armor was very weak and was to go upwards to 65 km/h.

Cadillac's design was heavier and featured 4 crew members which improved the fighting performance of the 152 mm armed vehicle. Armor protection was improved over the AAI vehicle, but was to be aluminum. In June, 1960 the Cadillac AR/AAV was accepted for further development as the XM551. Armament was decided in 1961 to be the 152 gun-launcher which won over the M32 76 mm gun, the M41 90 mm gun, and  105 mm gun(an M68 was mounted eventually in the 1980s actually just so you know). A 285 hp engine was mounted in the XM551 giving it some speed. Testing began at Aberdeen in 1962. These tests proved the XM551 was full of issues. FOUR more "generations" of pilot XM551s were tested until most of the chinks were worked out. You would think that if this thing needed so much modifications that it might not be worth it. By 1965 production of the M551 Sheridan commenced. In combat however the M551 was a failure.

Here is an excerpt for the book The World's Worst Weapons on the M551. 

"The resulting vehicle(M551) was all but useless for anything except distracting enemy fire from more useful assets." 

By 1970 the Americans started development to replace the Sheridan, the US never did adopt another light tank though. Many projects, some conventional some outright weird, we drawn up and some where extremely close to production. Today the US relies on the Abrams, Bradley, and a plethora of other vehicles to fill the void.

Now in WoT the Detriot Arsenal T71 is already in game and is expected to have the hull changed. The Cadillac T71 would be a great addition to the game being a good tier 7 light material. AFAIK the T92 is on track to become the tier 8 light tank after the M41. I personally would advice WG to reconsider the T92's position. It doesn't offer any great advantage over the M41 in anything, the T92 would be a let down at tier 8. If I was a developer the T92 would be a tier 7, maybe a crossover vehicle between the M41 and T71(DA). The XM551 is tricky. The 152 mm gun-launcher would be limited to only HE and HEAT rounds and guided missiles is a no-go. The armor of the XM551 is extremely weak and is liable to catch on fire every time it is shot.The Sheridan also is less comfortable(only -8 depression compared to the -10 on most other American Lights). Due to these reasons the XM551 should be excluded from WoT IMO.

Sources:

Sheridan: A History of the American Light Tank vol. 2 by R. P. Hunnicutt

The World's Worst Weapons by Martin Dougherty 

Digging Deeper (1) - Shell Normalization [revisited]

By Thor_Hammerschlag

The article was first of all released in an unfinished form. I am sorry therefore, Silent Stalker released it because I send it to him, however I only wanted to let him see on what I am working on. I didn’t write it down in the email that it shouldn’t be posted in this from so it is my mistake as well.

From now on mistakes like that won’t happen again, I joined the blog as you might read already!

About the article itself: It contains a lot of technical content. I wouldn’t be able to write it without an study of mechanical engineering, especially the mechanical part probably is not easy to understand.

Therefore I recommend reading it twice before trying to understand it for anybody who isn’t familiar with the subject of armor penetration.

I prepared a FAQ based on the confusion of the first article, you can find it in the end of this version. Also I reworked the article to make it easier to understand.

Digging Deeper (1) – AP Shell Normalization [revisited]

„God damn, I can’t believe that he penetrated me with that penetration at that angle! – that can’t be realistic!” 

We all know this kind of situation and most probably know the reason for penetration on such occasions:

Shell Normalisation.

But how realistic is the way shell normalization was introduced into the game? Currently the value – ingame - is for both APCR and AP shells between -5° and -4°. What does that mean? The angle of armor is negated by these values, resulting in less effective armor against AP and APCR shells than armor/cos(angle) suggest. Angling your tank at up to 20° barely makes a difference because of this phenomenon.

First of all, we need to consider that ingame AP-shells (armor piercing) been in reality a lot of different kinds of shells. Mostly, these 3 shells were in use:

Common shells of World War 2 [2]

AP: Armor Piercing round

Most common during the first years of the war, they were used by all nations.

APC: Armor Piercing round – with armor piercing Cap

Cap was set on the top of the AP a round to reduce shatter tendency.

APCBC: Armor Piercing round – with armor piercing Cap – and Ballistic Cap

Like APC - with an additional cap to reduce wind resistance.

These shells had all compareable normalization values, with AP having slightly worse values than APC and APCBC rounds. In this article all will be treated the same way.

After discussing the 3 most common kinds of shells, we will shoot such a shell against an armor plate and make a mechanical analysis. I prepared it for a AP shell. The following graph might explain the key problem with the penetration of sloped armor. The contact forces are calculated with F=p*A (pressure, and contact-Area, a rounded area all around the shell). This kind of 3 dimensional pressure-contact can mechanically be simplified by summing up the pressure of the lower and the upper part of the shell to 2 resultant forces. This is reflected here [1]:

(For all who want to dig even deeper, I prepared the whole mechanical treatment of the shell in the contact zone, something like this is seemingly missing all-over the web. It’s basically the static treatment from above and the dynamic treatment (principle of D’Alembert [1]) – it explains why the shell penetrates armor at all.)

The result:

There is no Normalization for AP projectiles which negates armor (the term normalization is misleading mathematically, but to prevent confusion this article will still refer to it). On the basis of “WWII Ballistics - Armor and Gunnery” it is possible to calculate normalization values as we know them. Technically it is uncommon to work with them at all because of the complexity of the shell trajectory. However, these values are fairly good to understand the basics of AP shell penetration and the difference between World of Tanks and Reality.

Probably out of blue for the majority of WOT-players: The reality values are positive. Sloping leads to more effective armor than 1/cos(angle) suggests.  Also new - “normalization” gets higher values with a greater shell diameter (that means more mass per mm²). In other words: Small calibers are worse against sloped armor.  The normalization value increases significantly against higher angles. [2]

Also this kind of sloping explains most battle reports which were not understandable yet. Just to name a few: The IS-2 had problems penetrating the Panthers glacis on distance (with AP), or the 8,8cm L/71 of the Kingtiger was unable to penetrate the 100mm frontalarmor of the postwar T-54. [2]

Conclusion:

- (1) Bigger shells were more effective against sloped armor than smaller ones

- (2) Armor angling was a lot more effective than reflected ingame

  (3) HEAT shells are more effective against sloped armor than AP/APC/APCBC shells [2]

- (4) The conversion of german penetration-data from 30° to 0° was done with Armor/cos(30°+normalization) as basis, however negative normalization values were put into the formula, which were actually positive values, creating less penetration for 0° data

Sources:

[1] Prof. Dr. –Ing. von Bredow: Script Dynamics (University of Applied Sciences Würzburg-Schweinfurt)

[2] Lorrin Rexford Bird and Robert D. Livingston: WWII Ballistics: Armor and Gunnery

Now for those whos brain is not broken yet, here is a FAQ which might clear up some unclear things. 

FAQ:

1: Wargaming explained normalization in a different way..

(link to WG video, at 4:30)  

Probably a really confusing video. The video is good, however the effect they describe was only reflected by a single type of shell in the 2^nd World War. The Soviet APBC shell (Armor Piercing Ballistic Capped), I might explain that effect in an article in the future. [2]

You can see it besides the types of shells we know already, it is on the right side. You can recognize it on the blunt nose (behind the white Ballistic Bap) which is also in the video. [2]

2: Wikipedia says, that the length of the projectile is also very important when it comes to normalization..

That is correct. Follow the digging even deeper link, it shows where this effect comes from. This is a really complex feature but I will explain it. You will see the moment of inertia in the link, the blue circle around the center of gravity. This moment works against the moment created by the forces which turn the shell and make the shell ricochet. The moment of inertia increases with shell lengh, thus makes it harder for the contact forces to turn the shell, which results in less normalization.


3: You are saying there is a big mistake? Why you are not making suggestion on eu forums about it?
Yes there is quite a big mistake. I might do that one day, but realistic shells and slope effects would require massive rebalancing.

4: My IS-3 sure would appreciate that...

Absolutly, the frontarmor of a real IS-3 was incredible strong against most WW2 projectiles.

Also, WOT is somehow unabled to reflect 3D sloped plates armor ingame. (angleing it does take into account however)

IS-3 front works like 110mm @56° which is currently 175mm ingame.

Same for is-7, 150mm @65° which is 300mm frorm the front (tested)

source is www.wotarmory.com for the IS-7.

Might write an article about actual performance of Pike-Nose armor one day.. 

5: there is nothing wrong in converting data, WG simply used Soviet criteria (Which was most strict then German, US and UK) for most guns.
Soviet criteria is less strict than the german one [2]. German criteria is 5 successfull penetration is a row and not 50% success.
According to [2] you have to multiply soviet test results by 1,06 and german by 1,14 in order to receive 50% success data. To estimate german combat ammo results you have to multiple the data by 0,943 [2] (for example for a 88mm shell) in order to estimate combat ammo penetration.

Article about how to estimate german 0° penetration at 50% success will follow.
(doubt the 1,14, but the book has great sources, will see what i will do regarding the article)


6:  F=p*A equation, it is quite useless, since you do not know the pressure involved..
Here lays another engineering aspect. Over the extent of the shell the pressure is pretty constant, with the one on the lower possibly being higher than the on the higher side because of more plastic deformation and solidification.

But even if the pressure on the lower side is as high as on the upper side, there is one significant difference. The area on the lower side - it is in any case larger than that of the upper side of the shell. Thus creating a larger resultant force.


7: Soviet guns penetrated more IRL as well..
I said nowhere that they didnt. But the subject is normalization and thus sloped armor and the error WG made specially at this point in armor conversion was my last point of the conclusion.

If you compare german to soviet penetration ingame the difference to RL data is not that huge (only talking about the differences) but compared to any other nations data (which used AP based projectiles) the german data is really damn wrong.

Germans get ~30° data, to compensate that they get APBC normalization. On the other hand
US data for example is 50% success data (at a softer plate), ingame they get APBC like normalisation for their full penetration at 0° (for many guns).

Some penetration data where nerfed and buffed others were just buffed. That would be okay regarding balance. But they say also that its technically correct what they do, and that is very very wrong.

Anyways, soviet data is also worth an article..



8:How can they have same normalization when the latter ones are developed FROM the former AP shell IN ORDER TO IMPROVE normalization?

APC and APCBC were NOT developed to improve normalization. 

APC - this cap was specially developed in order to reduce shatter tendency [2]

APCBC - like APC, with a cap which let penetration drop less on distance [2]



9:I have just put my hands on a library copy of "WWII Ballistics: Armor and Gunnery". Could you, please, post a short comment on how you calculated the "real" normalization angles. 

First of all we need to be aware of the fact, that normalization values are something to simplify the process of penetration and give an idea about how the angle of the armor changed the shell directory.

Extending the WOT german tech tree - artillery branch

By Zarax

Disclaimer: 
This is a purely speculative article that takes into account WOT german tech tree and uses historical tanks to speculate possible new tank additions.
While trying to keep the articles faithful to history some room for inaccuracy is allowed within these rules:

1) No tank or tank part will be 100% made up, at least a mention about tank role and vague specs are needed

2) Components not planned for the tank are allowed, provided it wouldn't create grotesque inaccuracies like putting a gun that would obviously cripple a tank under its weight

3) This will be limited to WWII plans, anything post war risks to be too arbitrary to properly balance

No serious expectation of anything listed to appear in WOT as described is applied, but as we're discussing about implementing history into an arcade game some items will be controversial.
This is unavoidable as WOT tech tree rules need a tank to be better than the previous one and ergonomics are not exactly cared about, meaning that most designs are over-performing their real counterparts.

In this article we will tackle the most controversial WOT tank class: artillery.
Right now there is a full branch spanning from tier II to tier VIII, however we do already know that WG will extend it to tier X, rebalancing tanks in the process.

Starting from this, we'll try to guess how this will happen:

Tier II: Sturmpanzer I

No radical changes are expected other than minor tweaks.
WOT made its gun unhistorically weak and used it as low tier artillery, while in reality, the SIG 33 was a quite powerful gun made for infantry companies.

The heaviest gun in its class, it was a very powerful howitzer, although inferior to rivals of similar bore due to low range. The short barrel was the price to pay for having a high caliber howitzer manageable by non motorized troops, which made it powerful but short ranged.
It ended up being replaced by a copy of the russian 120mm mortar, which offered only slightly inferior firepower in a lighter and longer ranged platform.

The very first attempt to motorize the gun was based on the obsolete Panzer I chassis, but it resulted in an extremely overload vehicle.
Somewhat compensating this was the fact that the original mount was kept, making the gun easily dismountable should the chassis break down (as it often happened).

Tier III: Sturmpanzer II

No radical changes are expected other than minor tweaks.
WOT made its gun unhistorically weak and used it as low tier artillery, while in reality, the SIG 33 was a quite powerful gun made for infantry companies.

Historically, WOT configuration was only moderately more successful than its predecessor.
Production was pretty limited and most Panzer II chassis were converted to use the 105mm L/28 field gun.

Ironically, the Sturmpanzer II with SIG 33 was found to be most effective in a direct fire role, with the 15cm shell angled in a way that made it ricochet over soft ground and explode in mid air, becoming deadly against infantry.

Unfortunately the vehicle was still under powered for the weight and its weak engine ran hot in the African climate, resulting in the following report in late October 1942:

The weapon has proven itself to be very effective, especially when using ricochet fire.
The Panzer II chassis is insufficient and didn't proves successful.

Tier IV: Grille

Unlike its predecessors, the Grille has been upgraded beyond historical parameters.
In WOT it's a tank both loved and hated: it packs a strong punch for its tier, yet the limited traverse makes it difficult to use.

We can also speculate that MM will be made slightly easier and the tank itself nerfed, but how?
Going into a stricter realism path, the 10.5cm LeFH 18 is the closest option in weight and would basically make the tank a faster-firing Wespe (which would be likely rebalanced by lower ROF as well).

A less likely but still possible alternative would be to use the 12cm GrW 42, which actually is a mortar, but it has a preceding case in WOT already (crusader's howitzer was a mortar) and would allow the tank to retain a reasonably stronger punch than the Wespe.

Tier V: Heuschrecke 10

Su-26 OP! Nerf it!

I'm sure most of you read that sentence at least once in WOT.

The Heuschrecke (Grasshopper) 10 was a prototype tank that brought both the concept of self-propelled gun and german over-engineering to new levels.

Not only the 10.5cm LeFH 18M cannon was supposed to be in a fully revolving turret, but it was also planned that it would be dismountable and used as a separate field gun:

Don't be fooled by the pic above, firing while on board was in the specs, which of course made them complicated enough to produce that it never went beyond prototype stage.

The GW Panther in WOT  that many players love is part of the same family of vehicles.

Let's talk specs: 

The base gun would be a slightly improved version of the 105mm L/28 used on the Wespe (and on many tanks in the german tree) and historically an improved (L/35) version was proposed by Krupp.

This would give it lowish alpha for tier V, but one has to consider the advantages of a turret and the fact that MM spread will be lower in a full tier configuration.

Unhistorical but possible options would be the 12cm GrW already discussed for the Grille or the 15cm STUH 43, used historically on the Brumbarr:

This would be a powerful gun, balanced by lower ROF and shorter range.

Tier VI: Skorpion

After planning a turreted SPG on Panzer IV chassis as Heuschrecke 10, an Heuschrecke 12 based on the Panther chassis was discussed in 1943.

Krupp and Rheinmetall both proposed different designs, respectively called "Grille" (which was part of a planned line from 10 to 21, with the numbers being the cm of gun caliber to be carried) and "Skorpion".

The pictured design, classified as Gerät 5-1213 is very close to the original Panzer IV based concept, while carrying a 128mm cannon capable of indirect fire.

This was a variant of Jagdtiger's gun, which was extremely accurate even in indirect fire, to the point that it was often pressed into the counter-battery role.

Again, this would be a design with a lowish starting alpha but decent upgrades.

The starting gun could be the top one of the previous tank (as often with artillery), with a 128mm L/55 as first upgrade.

As top gun, I'd like to consider two options:

The first would be the historically planned 15cm SFH 43, aka Hummel's gun. This would entail a very short grind for seasoned players and give a familiar gun in a very powerful platform.

A less realistic but still not impossible in WOT would be to follow Rheinmetall guns and use their long 128mm (aka Sturer Emil's gun) cannon as alternative.

This would give a very flat trajectory gun with excellent range and short travel time, although with less punch than a 15cm howitzer.

Tier VII: Hummel

No radical changes are expected other than minor tweaks.

Historically the Hummel was  born as an interim solution to the necessity of a self-propelled mount to the 15cm heavy howitzer.

In WOT the tank is portrayed as a well-rounded mid-tier artillery and fulfills its role pretty well with its historical gun.

Tier VIII: GW-Panther

No radical changes are expected other than minor tweaks.

The Heuschrecke 15 (known in-game as GW-Panther) was the natural follow-up of previous Panther-based proposals.

The design in WOT was made by Krupp and classified as Gerät 5-1528.

It was initially designed to use a fully enclosed turret, but as this would have made the design too heavy, a partially open superstructure was chosen instead and use of the Panther II chassis was planned for production.

Gun-choice wise, it was planned to use a 15cm howitzer, just like the Hummel.

A 21cm mortar (21cm GRW 69?) was discussed but it's likely the chassis would have needed to be redesigned for the purpose (plus it would be OP in game or balanced by horrible accuracy and travel time).

Tier IX and X: GW-Tiger and GW-E

No radical changes are expected other than minor tweaks.

Historically the GW-Tiger in WOT is the Grille 17 and 21 designs mixed in one tank.

The project started in mid-1942, where an heavy self propelled gun based on Tiger components was requested.

It was then delayed in order to be redesigned for the use of Tiger II/Panther components and the first prototype was to be expected in mid-1944.

The allied bombing campaign however caused further delays, with the single prototype not yet complete in early 1945, when work on it was ordered to be ceased.

There were plans to extend the Grille series to 30 and 42cm heavy mortars (likely related to the sturmpanzer Bar project, which will be covered later on), but those were eventually abandoned in favor of rocket artillery like the Sturmtiger or railroad cannons, while the Karl-Gerät covered the self propelled siege mortar needs.

Needs moar Panzers...

Hello everyone,

I am pleased to announce that Thor_Hammerschlag from EU forums will be joining the FTR crew. Next to Zarax, he's another Panzer fan, but also likes to theorycraft, so we can expect some very interesting articles!

You might have noticed that the "Digging deeper" article from Thor disappeared for now. I was informed by Thor that it is simply not yet finished, it will be improved and some concerns raised in the comments will be explained in more details.

So, welcome Thor! :)

-SS

8.4.2013

- second round of 8.5 test will start on 11.4.2013 apparently (changes are not available yet)
- there aren't so many city maps, because they stress the server more than "regular" maps
- Asian maps (Dragon's Ridge, Pearl River) were introduced in order to satisfy the Asian audience
- maps with rain/snowing effects won't come this year
- the problem with night maps is the implementation of dynamic lighting, dynamic lighting is planned for very distant future
- the 10 second drown time is not planned to be increased
- old render will not be optimized (improved) anymore, only the new one will
- the game will undergo a color-rebalance (SS: filters were mentioned earlier)
- currently, the skill of the drivers is not taken into account when balancing vehicles
- installing high-res skins and other addons can theoretically lower the game performance
- WG doesn't have enough data to buff/nerf British TD yet
- tank balancing is not done automatically, but manually and individually
- the fact HE explosions have little effect on the light tank vehicle movement is intentional
- exhaust vapours will not be made thicker (as they were before)
- T-80 MM spread is not yet decided apparently ("wait for the patch")
- developers are working on improving the account security (maybe including the possibility of "restoring" sold crews after the account was hacked) because there have been more cases of account stealing lately
- 3 arty per team hardcap will not come
- for now, no high-octane diesel fuel consumable is planned (for German diesel tanks)
- open-topped vehicles will not get a buff (SS: connected to the question how some open-topped vehicles were dealt with after they had the "improved ventilation" removed)
- no plans for tier 10 LT's
- SU-100Y is doing normally statistics-wise
- no (torque) difference will be implemented between the diesel and gasoline engines
- post-0.7.0, the armor system has not changed: 16 armor groups for turret, 16 for hull
- ST-I armor angles are historical
- devs have so far not thought about introducing Soviet lend-lease vehicles into the historical battles concept
- if you destroy a low HP enemy by ramming, you will get back the same damage as if the enemy had full HP
-  Storm on patch 0.8.6: "Get ready. The patch will be nuclear. A lot of rebalancing. Will tell more in about a month." It will contain tier 10 arty, amongst other things.
- Poole medal was not rewarded retroactively, because it was harder to implement than for example the Lion of Sinai medal.
- tier 10 alternative German TD will be a "German nightmare and horror" and "something special".
- Q: "Will it be a nightmare and horror for its owners?" A: "For whiners - definitely" and "only for German-lovers"
- generally, the state of module unlock has no effect on that vehicle's MM spread
- second full branch of Soviet medium tanks - "distant future"
- Soviet premium T7 med is not yet modelled
- there are many Soviet archives not yet uncovered
- US premium TD will come next year

IT-122 and IT-130 tank destroyers

Recently, in a new article about the foreign use of the T-62 tank (an interesting subject by itself, by the way) an interesting vehicle was mentioned: the Soviet tank destroyer IT-130 (along with the rather well-known IT-1 rocket tank destroyer), based on the T-62 hull. I did a quick research and here's what I found:

In 1978, a GRU officer Vladimir Rezun, known nowadays under the pseudonym of "Viktor Suvorov", defected with his family to England. Rezun worked as a military analyst. Naturally, he caught the interest of British secret service, whose officers debriefed him. It is not clear whether "Suvorov" was (is) a double agent for the Soviet Union or not, but basically in time it was discovered he made all sorts of shit up, including two tank destroyer designs: the IT-122 and the IT-130.

Now, the name itself is interesting. IT stands for "istrebitel tankov" - "tank destroyer". Wartime and post-war self-propelled guns were generally referred to as "SU" ("samochodnaja ustanovka" - "self-propelled gun"), the "IT" designation was generally obsolete and belonged to some pre-war project (namely for example the IT-45, or "Soviet Hetzer", a small and cheap tank destroyer early war project, scheduled to appear in WoT next year by the way) . Its use for post-war tank destroyer was strange.

It is not known whether the British secret service fell for it or not, but both designs somehow made it to the western literature, including Steven Zaloga's older books (Soviet Assault Guns, 1983). Not much is known on Suvorov's IT-122 project, but in literature, it is often paired with these images:

Seen it before? I thought so, because the vehicle on the images is the SU-122-54, a tank destroyer based on the T-54 from mid 50's, which is already in the game as a tier 9 tank destroyer of the alternative Soviet TD branch. It is my belief (and S.Zaloga's, who later corrected the information) that the SU-122-54 design got somehow mixed into the whole mess, designated IT-122 and made it eventually into various western literature sources. The same opinion is also shared by SerB, who at some point last year stated that the IT-122 is a fake and is in fact a case of mistaken identity of the SU-122-54. Here, a real SU-122-54 picture:

The IT-130 idea came from the same source. In this case, according to Suvorov's info, it is supposed to be a T-62 based tank destroyer from the 60's, equipped with a 130mm cannon, with similiar construction to the "IT-122". The only source of the cannon identity are the sketches from "Suvorov" (the following picture depicts the "IT-122",the 

The identity of the 130mm gun was not clear either, as at that time, the names of the Soviet guns were not really known. It was reported as "M-46", but who knows...

Either way, both of these tanks (under such designations) never existed. There however WAS a real ISU-130 project. Designated "Object 250", it was an experimental vehicle based on the IS chassis from 1944, built at Factory No.100 under the supervision of the famous Soviet tank designer, J.Kotin and equipped with a naval 130mm gun, designated S-26 (the original name was B-13). It was a basically an ISU-152 with a different gun (the gun was equal in power and penetration to the BL-9). Only one prototype was ever made and tested. This is how it looked:

Sources:
S.Zaloga - Soviet assault guns
Alex_Mitsch's thread on the IT-130
www.valka.cz