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May 30, 2013

Chi-Ri - Imperial Japan's most advanced tank

SS: Today, we have a guest article from SoukouDragon (US server) on one of the (confirmed) Japanese hightier tanks. Enjoy!

Author: SoukouDragon


A Japanese Tiger? No

When Japan surrendered, American forces discovered Japanese late war military projects all over. One of such was the biggest Japanese tank U.S. forces have ever seen, the seemingly half completed Chi Ri, sitting there without a main cannon installed. The turret was huge. More than large enough for a 75mm cannon. There were some Japanese 88mm AA cannons so Aha! Just like the Germans, they must have been planning on putting these 88mm cannons in the Chi Ri! And behold, the idea of the Japanese Tiger was born.

Wrong.

Recently, in Japan, more research has been going on. In documents about the Chi Ri`s development, there has never been any mention of installing an 88mm cannon in the Chi Ri or on any other Japanese tank. But what these old documents have revealed the reason why the turret was so large. It was meant for a 75mm belt-fed auto loader.



The Chi Ri is big... very big.

Length/Width/Height in meters
Type 5 Chi Ri: 7.3/3.07/3.05
King Tiger: 6.4/3.76/3.09
M4 Sherman: 5.84/2.62/2.74

It could fool anyone into thinking that there was a lot of armor on the thing, like the Tiger. But no, it may be disappointing, but the front armor of the turret and hull was only 75mm. The side armor ranged from 25 to 50mm in thickness. Despite the size, it weighed only 37 tons. This is by no means armored like the 55 ton Tiger. The Chi Ri was not designed as a heavy tank; it was designed as a medium.

So a gigantic medium tank with modest armor…how is that advance? Sounds more like inefficient use of armor…

A Brief Historical Background

1942: Three new anti-tank capable Japanese medium tank projects
Kou: 47mm cannon….eventually grows into Type 4 Chi To
Otsu: 57mm cannon…eventually merges into the hei plan
Hei: 57mm or 75mm cannon…eventually grows into the Type 5 Chi Ri.

During 1943, by looking at the tank battles between Germany and Russia, there was fear that the Chi He and the Chi To could be underpowered by the time they would enter production. At this time, many technological inspections and planning have occurred for the Chi Ri. These included ventilation, transmission, suspension, 550 HP gasoline engine, and easy access to the engine for maintenance. Targeted top speed was 42kph. Improved ventilation was necessary because of the anticipated increased influx of poisonous gas when using the high rate of fire from an auto loading cannon. The main armament would become the Type 5 75mm cannon. It was planned to attach an auto loader to it. Here is a picture of it being tested with the single tray auto loader.



75 mm Gun Type 5


Shell Weight: 6.615 kg
Muzzle Velocity: 821 m/s
Kinetic Energy: 2229 kj
Historical Pen: 75 mm (1,000 meters) goal (met), 80 mm (1,000 meters) expected
Gun Depression in Chi Ri: -6.5 +20

However, steps were taking to ensure an even more advance design could be made available.

In September 1943, a plan 1 and a plan 2 were outlined for the Chi Ri. The goal of plan 1 was to use the current technology developed so far to produce a finished Chi Ri within 1 year. Plan 2 was an ambitious plan to push the edge of technology. The Chi Ri tank discovered by the American forces was the Plan 2 tank.

Chi Ri Plan 1






Chi Ri Plan 2


The biggest difference between plan 1 and plan 2 was the suspension and the turret.

Chi Ri Plan 2 Suspension Options


There was a total of 6 suspension plans examined. Three plans from the Technology Research Institution (TRI) and three from Mitsubishi Heavy industries (MHI).

One plan from TRI was a common Japanese style coil spring suspension which was already proven to work on other Japanese tanks. The other two plans were staggered arranged road wheels much like the notorious suspensions found in German tanks like the Tiger and Panther. One with coil springs like this picture and another with torsion bars.



The three plans from MHI were 6 large road wheels. One was with coil springs and one with torsion bars.
Ultimately, the Japanese went with what they were used too.


The Suspension used very wide treads. The width was 600mm. For a 35 ton class tank, this would have produced a very impressive ground pressure value. The goal was a ground pressure of about 0.6 to 0.7 kg/cm². Compared to other tanks, this was a very good value.

M46 has: 0,986 kg/cm²
KT has: 1.03 kg/cm²
Conqueror has: 0.84kg/cm²
Crusader Cruiser has: 1.04 kg/cm²
Centurion (1 I suppose) has: 1,04 kg/cm²
M48 has: 0.92 kg/cm²
T-54 has: 0.81 kg/cm²
T-34/76: 0.66 kg/cm²
M103 has: .908kg/cm²
M5 Stuart has: 0.856kg/cm²
M4A1 Sherman has: 0.962kg/cm²
M4A3 (76mm + HVSS) has: 0.772kg/cm²
M26 Pershing had: 0.878kg/cm²

Out of all these tanks, only the T-34/76 could match. This makes a very strong case for good hull traverse and low ground resistance. They must have been thinking about rice paddies.

Chi Ri Plan 2 Turret

In order to accommodate a load of 100 75mm rounds and to fit in a belt style auto loader, the turret was enlarged. The plan 1 turret would likely not be capable of handling this task, therefore the large turret was designed. To increase the speed of target acquisition, the turret would rotate by an electric motor, increasing the speed of turret rotation. Another advanced feature was the gyro-stabilizer for the 75mm cannon. It was demanded for the Chi Ri to be able to engage targets up to 2000 meters away so a long range observation device was installed. One other feature is that it was the first Japanese tank, and one of the few tanks in all of WWII, to have a turret basket built in.

Probably the most controversial feature was the secondary 37mm cannon. It was likely intended to be used for soft targets that would be overkill for the 75mm cannon and thus free up the 75mm for more critical targets.

In 1944, the belt fed auto-loading cannon was abandoned. Likely due to the anxiety of trying to create a belt system that would move 900mm long shells around within the turret. However the large turret was already designed. In its place, a single tray auto loader was to be attached to the Type 5 75mm cannon instead thus still maintaining a fast rate of fire. It is believed that very likely the Chi Ri underwent running and shooting trials in March 1945. However, the simpler Type 4 Chi To was selected over the Chi Ri for production. The likely reason why the Chi Ri was found armless is because the Chi To mounted the same 75mm cannon and thus the Chi Ri’s 75mm cannon was likely moved to a Chi To tank.

Adding the Chi Ri to World of Tanks

Here I will describe how the Chi Ri could be implemented into the game as a tier 7 medium tank.

The Engine was a 550 horse power de-tuned version of the Kawasaki H9II 800 horse power engine. At 37 tons, that would give it 14.8hp/ton.


Here is a list of HP/ton of other tier 7 medium tanks with their top engines
T20: 18.6hp/ton 560hp
T-43: 17.6hp/ton 600hp
VK-13: 18.3hp/ton 600hp
VK3002D: 18.4hp/ton 720hp
Panther: 16.6hp/ton 750hp
Comet 20.3hp/ton 650hp

For the needs of the game, a little more horse power would be needed. With the 800 HP H9 engine, there is a lot of potential for upgrades from the 550 HP point. Essentially, a suitable de-tuned value could be determined for balance purposes; as long as it does not exceed 800. A top engine with 675 HP would give the 37 ton Chi Ri an 18.2hp/ton rating.

Gun Choices

Estimated values for 4 cannon modules

Tier 6 Type 5 75mm model II (no auto loader)
AP Damage: 135
AP Penetration: 137
Rate of Fire: 14.5 r/m
Accuracy: .36

Tier 6 Type 5 75mm model I (single tray auto loader)
AP Damage: 135
AP Penetration: 137
Rate of Fire: 19 r/m
Accuracy: .36

Tier 7 Type 5 75mm belt fed auto loader (requires upgrade plan 2 turret)
AP Damage: 135
AP Penetration: 137
Rate of Fire: 30 r/m
Accuracy: .36

Tier 7 Type 5 88mm cannon (requires upgrade plan 2 turret)
AP Damage: 220
AP Penetration: 144
Rate of Fire: 10 r/m
Accuracy: .38

Picture of the 88mm


Hit Points with top turret: 1200

Main Armor type: Cast Steel

Front Hull: 75mm
Side Hull: 50-25mm
Top Hull: 20mm
Rear Hull: 50mm
Bottom Hull: 12mm

Front Turret: 75mm
Side Turret: 50-30mm
Top Turret: --
Rear Turret: 50

Mobility with supposed 675 HP top engine.
Top speed: 45kph
Traverse speed: 38 d/s
Upgraded Turret Traverse: 46 d/s

Strengths

High DPS with either the alpha hitting 88 or the rapid fire 75.
Good mobility.

Weaknesses

Very big tank means very bad camo, difficult to get behind cover.
Weak Armor makes it a punching bag if exposed.

The expected game style of this tank will be taking advantage of its high DPS potential. The 75mm belt cannon gives it insane DPS potential in a sustained brawl but loses out in long range shooting compared to other sniper capable cannons or peek-a-boo tactics with its low alpha and penetration. When wolf packing or against a distracted enemy, the 75mm belt fed cannon will decimate a target in short time. It will bully anything the cannon can penetrate. However heavy armor will nullify a Chi Ri tank armed with the 75mm belt fed cannon.

Something curious about the belt fed cannon is that it seems to be unknown as to how the crew could swap between HE and AP rounds with a linked belt system. In concept, the Chi Ri was designed as an anti-tank medium tank. It could be that all 100 rounds were AP rounds. That does present an explanation for why the 37mm cannon was put on, for it`s HE ammunition. But that is pure speculation on my part. Sadly as I researched into this tank, more questions arise. But anyway, if the belt-fed cannon was to be an AP only weapon, then it does make for a risky play style, but, I feel, a popular niche.

The 88 offers a higher alpha and marginally better penetration for more common brawl style playing. With the higher alpha it gives the Chi Ri the ability to peek-a-boo and premium rounds or the better HE rounds give it the ability to deal with heavier armor better than the 75mm cannons.

While the 88 was not planned for the Chi Ri, the very large turret would undoubtedly be able to handle an 88mm caliber weapon.

What this tank cannot do is run out in the open. It will be spotted. It can’t be sneaky, it is just too large. Its armor can also be penetrated by just about anything. The maximum 75mm armor is not even well sloped.

Sources:


Maru [丸] 2011 October magazine edition. 平成23年10月一日発行 
WoT Discussion forum: Japanese Tank Tree & Guns Discussion: Posts by Daigensui and Lostwingman.
World of Tanks Wiki 8.5

34 comments:

  1. Knowing WG they would probably give it 300mm pen with prem ammo, otherwise it just isn't worth grinding. Looks like a horrible tank.

    ReplyDelete
    Replies
    1. It'll be like a bigger VK3002DB.

      Delete
    2. are you kidding? 135 damage with 1.70 second reload would make for an extraordinarily fun tank. think about how fast you could decimate an unexpecting opponent, or how you could perma track / perma destroy turret ring any tank you can penetrate.

      I'd play that mofo for hours and hours!

      If the thing is belt fed though, wouldn't it make more sense if WG gave it a 20 round autoloader with some 40 seconds of reload? Would be able to deal 2700 damage within 30 seconds, but then would need to reload for another 40.

      Looking forward to this one

      Delete
  2. Tier 7 Type 5 75mm belt fed auto loader (requires upgrade plan 2 turret)
    AP Damage: 135
    AP Penetration: 137
    Rate of Fire: 30 r/m
    Accuracy: .36


    Why it will never happen: DPM=4050

    ReplyDelete
    Replies
    1. gl penetrating tier 9s lol

      Delete
    2. Yea, not like there aren't tier 7s with similar or weaker pen...

      Oh wait...

      Delete
    3. there is not any tier 7 whose top gun has weaker pen than 137. No, the 8.8 on the VK3002DB is not the top gun, you want to run the 75 L/70 imo.

      Delete
  3. Datdpm.jpg

    I get this thing ASAP

    ReplyDelete
    Replies
    1. This is unofficial speculation from someone knowledgeable on Japanese tank development, not an actual release from Wargaming. No one outside the company has seen any actual stats yet, if they even exist right now.

      Delete
    2. Aesir, WG isnt the world. They MAKE UP stats for tanks as they see fit, and later they say its "historical". So shut up.

      -EmperorSafirius

      Delete
    3. No shit, they make up stats. This game is rife with historical inaccuracies.

      What I meant is that he shouldn't get his hopes up for the Chi-Ri in WoT because of Soukou's analysis. It will be an interesting vehicle to play, probably, but that doesn't mean that it will translate to a monster DPM in game. Everything is subject to Zlobny and his supertesters, and there is no way to know if Wargaming will set up the Type 5 as described here.

      So get off your presumptuous high horse, and stop being a cunt.

      Delete
  4. Thx for the well written article

    ReplyDelete
  5. Indeed, thanks for a very well researched article...hopefully, someone will direct the appropriate eyes from WG to it...

    redwing6
    CO, The Blues & Royals (TBR on NA)

    ReplyDelete
  6. not saying men of war is historical but the chi ri there uses a 88mm gun also there the jap 88 has much more pen than the current lame german 88

    ReplyDelete
  7. I'd rather see the belt fed gun having a 5 round autoloader with 0.5-1 sec inclip reload.

    ReplyDelete
    Replies
    1. Unless it had an amazing aim time, you would be spraying shells all over the place when firing at full speed. -Platypusbill

      Delete
    2. xCaptainObviousxMay 31, 2013, 2:31:00 PM

      I was thinking a bit like the 59-16's 76 m autoloader... but with resonable pen.

      Delete
  8. Germans had a belt-fed 105mm gun in plans, it was supposed to be used by the Porsche Typ 255.

    ReplyDelete
  9. Too weak for tier 7, but good enough as a tier 6 med imo.

    ReplyDelete
    Replies
    1. I have to disagree. At tier 6, the Type 75 belt fed would be able to penetrate most targets it encounters with standard AP. What brings the belt-fed to tier 7 is not Pen or Alpha, but RoF.

      Many top tier 6 medium cannons are the 75 caliber cannon class but without that RoF. The belt-fed would be OP in tier 6. At tier 6, the Chi Ri would be able to fight long range just as effectively as most other tier 6 tanks but at close range, it would annihilate almost anything that comes near it. In order to keep that power in check, more of the Chi Ri's opposing tanks need to have better armor in order to repel the barrage of 75mm AP rounds...in order to make Chi Ri players play smart.

      Besides the 88 is competitive to the top guns on the T-43, KV-13, and 3002D.The T-20s 90mm has better pen and alpha but lower DPS.

      SoukouDragon

      Delete
  10. Looks interesting, but WG may go for a shorter rof as the French autoloaders shoot slower then the Americans. That would drop the dpm a lot, but it may still be playable.

    ReplyDelete
  11. nice article.
    But the KT length is wrong, its a common mistake pretty often reposted. The wrong source therefore is the english wikipedia articl. We had several discussion on the forum about it already.

    Look:
    http://img703.imageshack.us/img703/5052/ktcomparebyhammerschlag.png

    (hull vs. tankoverall length)

    and more sources with the right size:
    http://www.wwiivehicles.com/germany/tanks-heavy/pzkpfw-vi-b.asp



    Regards

    ReplyDelete
  12. >The Chi Ri is big... very big.

    Probably, WG may investigate Chi-Se (105mm gun version Chi-Ri. not Ho-Ri gun tank.)

    ReplyDelete
    Replies
    1. WTF is Chi-Se? 0 results in google.

      Delete
  13. Japanese searches of a Chi Se gave a little bit but all fantasy.

    SoukouDragon

    ReplyDelete
  14. ...did the Japanese have a principal aversion to coax MGs or something? Because having what appears to be the vehicle's sole "hard-mounted" MG sticking out of the turret side of all things in a late-war design has stupid written all over it...

    ReplyDelete
    Replies
    1. Who knows...they may have thought that side mounted MGs would be useful in Jungle environments. Maybe the belt fed cannon would have been in the way of a coax MG. Maybe it was a design flaw. But stupidity written all over it? A shallow point of view if I may dare say. This man spoke and looks odd, but is he stupid? https://www.youtube.com/watch?v=dxe5F7nUYsc

      -SoukouDragon

      Delete
  15. I made a mistake. Found mention of the Chi Se in the Maru magazine. Hmmmmmm It was what would be the successor of the Chi Ri and yes, would carry a 105 in the turret.

    SoukouDragon

    ReplyDelete
  16. WORST FUCKING Tier 7 in the game

    ReplyDelete
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