U.S. Army Ground Forces’ 150-ton Superheavy Tank

While proven to be much of a liability instead of a tactically useful asset, there is no denying that there existed a superheavy tank craze even during the WWII era, as displayed by each warring state attempting to develop their own version of such a humongous vehicle. Maus (188t), O-I (150t), FCM F1 (139t), KV-5 (100t), TOG II* (81t) were easily among the list of well-known superheavy tank designs throughout the war, some never even left the drawing board. The Canadians at one point were also considering building a superheavy tank with 4 inch naval gun turrets (courtesy of Whelmy). Speak for the obsession of gigantism.
Now, before you come over to piss me off that I missed out the T28/T95 from the US side, I did in fact recognize the 86-tonne bonker that has just recently been preserved and is now residing inside NACM’s tank house comfortably. But did you know that the T28/T95 wasn’t the only superheavy tank project that the US had come up with? Most people will most likely be familiar with the T28/T95 as the US’s sole superheavy tank project in their entire history, but are not aware of another type of superheavy tank thought up by the Army Ground Forces (AGF) during the last phase of WWII.
The U.S. Army Ground Forces’ 150-ton Superheavy Tank.
An artist’s drawing of the AGF 150-ton Superheavy Tank.

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T26E4 Heavy Tank with T32 Turret

The T26E4 was a heavy tank armed with a high velocity gun to counter the firepower of the latest German heavy panzers. With the T26E3 Pershing ongoing for serial production, the Ordnance Department had authorized a diversion of 25 T26E3s from their original configuration to mount the latest anti-tank gun in development, the 90 mm T15 L/73 high velocity gun. The first temporary pilot of the vehicle, designated as Heavy Tank T26E4-1 “Super Pershing” was sent into combat in April 1945. Using the earlier T26E1 hull, extensive modifications to its fire control was required due to the turret being originally designed to mount the shorter 90 mm M3 L/53 cannon only.

Temporary pilot T26E4, displaying two massive equilibrator springs to elevate the long-barreled 90 mm T15E2 gun.

A 90 mm T15E1 with single piece ammunition was hastily installed on the first temporary pilot T26E4-1. Because the gun proved to be too heavy for the tank’s size, the hull was heavily modified, requiring two large equilibrator springs mounted externally on top of the turret to control elevation of the gun. To balance the extremely heavy barrel on the front, a large counterweight was welded at the rear of the turret. Other modifications involved the installation of heavier elevation gear, turret traveling and turret ring locks, and the gun cradle. The second temporary pilot T26E4-2 retained all the modifications of the first temporary pilot, but had now used the hull of the T26E3 instead, and mounted a 90 mm T15E2 with separate piece ammunition.

As the T26 turret wasn’t clearly designed to adapt the 90 mm T15 gun, additional modifications were authorized for a proper production T26E4 by incorporating a hydropneumatic equilibrator mounted internally within the turret to replace the external spring equilibrator and rearranged ammo racks. This production version would later be applied to the remaining 23 T26E4s. However, as many modifications as there could be, the T26E4 turret remained the same as the T26E3 turret by design. It still couldn’t wield such a long-barreled cannon effectively without some reliability issues.

Production pilot T26E4, mounting the 90 mm T15E2 gun with an internally mounted hydropneumatic equilibrator.

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Patton’s Field Modified M4A3(75)W w/ 76 mm M1

On the subject of mounting the 76 mm M1 L/53 into the original M4 turret, a question pops up:
“If the original M4 turret was used to test an even longer 76 mm T1 L/57, why didn’t tank crews in the field attempt to replace their Sherman’s 75 mm with surplus 76 mm guns, considering it worked anyway?”
Well… They did.
3rd Army Ordnance’s modified M4A3(75)W w/ 76 mm M1.

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Standardized, Never Entered Service: 3-inch Gun Motor Carriage M9

The US Tank Destroyer doctrine was well renowned for its use of turreted self-propelled guns, designated as “Gun Motor Carriage” by the U.S. nomenclature in World War II. The intended role for this anti-tank vehicle design was to quickly adapt to the rapidly mobile battlefield, as well as to intercept, defend, and secure strategic locations against the enemy armored forces. A turret could provide an effective and immediate response against threats from more than just a single direction… even if some vehicles did not totally fit into that description (see the M10 TD and M8 GMC and their manually-traversed turret).

M9 Gun Motor Carriage at Aberdeen Proving Grounds, March 1942.

But such a design choice did not deter the U.S. Army Ordnance’s attempt to go on a venture and experiment with building turretless gun motor carriages. Most of them usually ended up as no more than just a single-working prototype to demonstrate their performance in trials. However, few of them made their way into a working interim solution until a proper turreted vehicle could roll out into production. Such an anti-tank vehicle was to be armed with an ancient 3-inch (76.2 mm) anti-air gun on top of a modified M3 Medium Tank chassis. Enter the 3-inch Gun Motor Carriage M9.

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The 120 mm T53

T34

You have probably heard about the American experimental heavy tank T34 somewhere, maybe from World of Tanks, War Thunder or Wikipedia. It’s described as having an excellent penetration at about 247 mm from 100 m, which is a feat compared to the German 8.8 cm KwK 43 gun armed on the Tiger II. But did you know that it could do more than that?

A bit of Background

The T34 was a WWII prototype heavy tank developed in 1945 in response to the German armored threats such as the Tiger II and Jagdtiger. The T29 was considered satisfactory enough in term of performance with its 105 mm T5E1, but lacked serious firepower in contrast to the 12.8 cm cannon. The T30 was only armed with a 155 mm as a bunker buster, with sub-par anti-tank performance across the board. As such, a project was initiated to rearm the T29/T30 with a modified 120 mm M1 AA gun, the 120 mm T53 L/65. Firing a 23 kg heavy projectile at 960 m/s, the gun was able to closely match the performance of said German gun. Unfortunately for the Americans, World War II was already over by the time the T34 was assembled. Post-War development led to the T34’s engine being upgraded from using the Ford GAC to Continental AV1790. Extensive trials of the T34 as a “technology demonstrator” led to the M103 Heavy Gun Tank.

Development

The earliest known record of the requirement to develop the T34 heavy tank was from the first of February, 1945. The Army expressed concern about using the 155 mm gun with heavyweight 100 lb projectiles on the T30 (M112B1), mainly because of the effectiveness of it against enemy tank armor, with the rate of fire calculated in. It was expected to be very ineffective (the M112B1 only penetrates 170 mm of armor from point blank, while the rate of fire from the gun is only 3 RPM). Seeing the potential problem that would likely cause an unnecessary issue in the future, the Ordnance Department went to study for possible application of the 120 mm M1 anti-aircraft gun for the heavy tank.

Screenshot_6

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The T30’s Ammo Box

Aberdeen 1

The T30 heavy tank has vague information when it comes to ammunition load. Some claimed it’s only able to fire HE, some said it only has low penetrating AP round, while the others describe it as having high penetrating “M111 AP” and “M112 APCR” that can penetrate 276 mm and 320 mm of armor, respectively.

Some Problems

While some of them are true, there is so little explanation on how the T30 acquired such loadout or achieved such penetration, leading to “what if” situation where the shells are configured according to whatever related sources publicly available.

1. It only fires HE shell

The most common misconception about the T30 is that it only has HE shell. Some people claimed so due to the reason that it’s armed with a massive, but low velocity 155 mm T7 gun used for anti-fortification and destroying building, instead of dedicated anti-tank gun such as the 105 mm T5E1 mounted on the T29. Although it’s understandable since many referenced the source from R.P. Hunnicutt’s book; Firepower – A History of the American Heavy Tank.

Firepower: 155 mm T7
As you can see here, it only has a HE shell with unknown designation for the 155 mm T7.

2. It fires low penetrating AP round

Information available from certain WWII forum usually points out that the 155 mm “AP” fired from 155 mm T7 was unsatisfactory and only resulted in low anti-tank penetration performance from velocity loss. I will explain this later below.

3. “M111 AP” and “M112 APCR” that can penetrate 276 mm and 320 mm of armor

So far, it’s very popular as these rounds are available in World of Tanks, used by both T30 and T95, even goes so far that the T110E3 and T110E4 received a much improved version with E1 designation in the back that can penetrate 295 and 375 mm of armor.

These projectiles in particular are “M111” AP, and “M112” APCR. It’s interesting and confusing at the same time… The only known use of designation “M111” is a 105 mm APFSDS “Hetz” intended to penetrate the Soviet T-72. While the “M112” is actually an AP round of the 155 mm gun.

Screenshot_10

… It might be good time to explain this thoroughly.

Opening the Ammo Box

The weapon loadouts will be described as detailed as possible. But let’s start from the basics. The 155 mm T7 L/40 is a 155 mm gun of the T30 heavy tank, developed from a shortened 155 mm M1 L/45 “Long Tom”, conceived as early as 14 September 1944. It was developed alongside with the T29 heavy tank armed with 105 mm T5E1 L/65 gun.

14 Sept 1944

The T30 had up to 5 different ammunition available for use. Starting from M107 HE, M110 WP, M112B1 APBC-HE, T29E1 APCBC-HE, and finally T35E1 APCR. The specification will be listed as fired from the T7.

DYun2mA

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War Thunder: Naval Forces CBT is here

The most anticipated upcoming War Thunder feature has arrived.
It’s the War Thunder: Naval Battles, introducing a new ship warfare mode available soon in one of the upcoming patches (possibly 1.63 or 1.65, since 1.61 was probably a rushed update meant to introduce 4 reward vehicles from “Operation SUMMER”).

The teaser of “War Thunder: Knights of the Sea” can be seen here: