How the 'jack-in-the-box' flaw dooms some Russian tanks

[Yo_Mama_Been_Loggin]

The sight of Russian tank turrets, blown off and lying in ruin along Ukrainian roads, points to a tank design issue known as the “jack-in-the-box” flaw.

The fault is related to the way many Russian tanks hold and load ammunition. In these tanks, including the T-72, the Soviet-designed vehicle that has seen wide use in Russia’s invasion of Ukraine, shells are all placed in a ring within the turret. When an enemy shot hits the right spot, the ring of ammunition can quickly “cook off” and ignite a chain reaction, blasting the turret off the tank’s hull in a lethal blow.



“For a Russian crew, if the ammo storage compartment is hit, everyone is dead,” said Robert E. Hamilton, a professor at the U.S. Army War College, adding that the force of the explosion can “instantaneously vaporize” the crew. “All those rounds — around 40 depending on if they’re carrying a full load or not — are all going to cook off, and everyone is going to be dead.”

British Defense Secretary Ben Wallace this week estimated that Russia has lost at least 530 tanks — destroyed or captured — since it invaded Ukraine in February.

https://www.washingtonpost.com/world/2022/04/30/russian-tank-turret-blast-jack-in-the-box/

The tank on the top is the T-72. The German Leopard 2 is on the left. The American M1A2 Abrams is on the right.

[Tree-Hugger]

1. I have the dumbest question

How does the ammunition get loaded from any of these positions? Do the soldier constantly load it? Is there an automatic mechanism?

[Archae]

2. I don't know about the Russian tank...

But I saw a video of the M1 Abrams, a door behind the loader opens, he pulls out a shell and the door slams shut again.
It's all very quick, and the crews train for best efficiency.

Here you go.

&ab_channel=MilitaryArchive

[dalton99a]

3. Manually:

Russian T-72:

[JHB]

5. The Russian one has an automatic loader

In the Abrams, one of the crew in the turret is a loader, and can access the ammunition via a hatch. The ammo compartment is designed so that in the event of a blast, the explosion goes upward away from the crew. In the Russian tank, "upward" is into the crew.

Not sure about the Leopard.

[GregariousGroundhog]

11. Russian tanks use auto loaders

The United States and western militaries have four crew members in their tanks, the commander, the gunner, the loader, and the driver. Soviet tanks only have three crew; the commander, the gunner, and the driver.

The United States experimented with autoloaders but decided against it for reliability reasons and because having a fourth set of hands is really useful when having to do maintenance in the field. The soviets preferred auto loaders because it allowed them to make a smaller tank and because it doesn't get tired and slow down after loading a couple of rounds like a human does - Wikpedia lists various soviet tank rounds as between 19 kg and 33 kg in weight (roughly 42 to 63 pounds).

In Russia's newest T14 tank, they've moved the commander and gunner out of the turret and into an armored capsule in the front of the hull. Production of the T14 was supposed to start this year, though I'm uncertain how sanctions will affect that.

[Hoyt]

4. But if the enemy shot hits the right spot, wouldn't the tank be disabled anyway.

Here the top blows off. On another tank design, the top remains, but everyone and the tank are blown to smithereens.

[Archae]

7. On the M1 Abrams, the shells "cook off" upwards, away from the crew.

[Hoyt]

8. Thanks. If I were in an M1, not sure that would make me feel safe, no matter

what the training manuals say.

[EX500rider]

9. Well a kinetic penetrator might kill all the crew on a western tank it also may not

Depends which way the cookie crumbles, basically the issue is spaulding, the molten part of the tank melted (blasted) inward, if it hits you you have issues, if it misses you you may have time to get out or only be wounded, not dead.

[Hoyt]

10. Too claustrophobic for tanks and submarines. But sounds like a well placed shell

might cost one a limb, at a minimum.

Drone operator or artillery sounds safer.

[GregariousGroundhog]

12. It also depends on what kind of round hits the tank

HEAT rounds that penetrates will spray a jet of molten metal (usually copper) into the tank. Depleted uranium is pyrophoric and so sabots made of it will tend to "self sharpen" as they penetrates; the dust that breaks away from the penetrator usually spontaneously ignites as it does so. I imagine the odds of surviving either scenario are not very good. If someone does survive the initial strike though, their odds of escaping a western tank is much better than Soviet ones (which are known for being extremely cramped).

[Demovictory9]

6. interesting