> and of course RPG has no top-attack (unless you're firing from a building, which as we've seen is tricky to get it to arm in time)
These tanks were planning to assault Kyiv. The assumption was that cheaper RPGs (such as the AT4) would be used against these tanks. The AT4 isn't designed to be used vs main-battle-tanks (AT4 has penetration of 450mm), the frontal-armor is too thick (500mm to 700mm effective frontal armor, depending on the tank, depending on the angle the attack hits from... Largely due to geometry, not physical thickness). But the "cope-cage" might be strong enough to deflect an attack against the turret (especially if the AT4 is "top down", because it was fired from an urban building).
There's many, many, many weapons of war. There are many different types of "anti-armor" weapons.
The Russians also know that the turret has the critical weakpoint of the tank: the autoloader. If the autoloader is hit, the entire tank's munitions blow up simultaneously (aka: cooks off), and everyone inside the tank dies. Protecting the turret with a "cope cage" (even if ineffective vs Javelins) to try and mitigate damage from other RPGs (AT4, RPG7, Panzerfaust 3) just makes sense.
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Javelins are the most expensive man-portable anti-tank weapon. There's relatively few of them (yes, I know USA sent thousands of Javelins, but we also sent far more simpler anti-tank weapons as well). Javelins are $170,000 per shot, and the AT4 is $1500.
The other man-portable weapon discussed, NLAWs, are like $40,000, much cheaper than a Javelin but still an incredibly sophisticated and expensive weapon.
Media ignores the cheap stuff (AT4, RPG7) because they're not really interesting. But those are probably the workhorses and the more common weapon in the battlefield.
[1] https://en.wikipedia.org/wiki/Skif_(anti-tank_guided_missile...
[2] https://en.wikipedia.org/wiki/Panzerfaust_3
But since they're larger / heavier / more expensive, they are the primary-weapon of the soldier (or squad, in the case of Stugna-P). If you're equipped with one of these, your job is to kill tanks.
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Panzerfaust, AT4, RPG7 are variants of the same concept. They're more of a "sidearm" than anything. You don't really want to be facing down a tank with one. They are manually aimed and therefore only effective at 100m to 300m (depending on how good your aim is).
Because they're smaller warheads (84-caliber for the AT4, yes its a pun/joke), they're less effective at penetrating armor. So you really want to use them vs lighter vehicles, such as IFVs instead of proper tanks. If you need to use it against a tank, you should aim for a weak point, like shooting from above, or hitting the side/rear armor.
So your snipers / riflemen / machine gunners have a job, that's the 50-cal, or machine-gun. But what if they come across an enemy vehicle? Well, the AT4 / Panzerfaust are light enough to carry _WITH_ your other weapons. Its better than nothing, and light enough to be a secondary weapon.
Alternatively, maybe you're in an environment where hitting the weak top-armor is possible (ex: Urban / high-rise building in Kyiv). Giving many, many cheap AT4 weapons out to the crowd of defenders will effectively kill even main-battle-tanks, if they are attacked at the proper angles / from their weakpoints.
This is a very common mis-conception. These weapons don't have a lot of explosive. They instead rely on very precise application of a little explosive, through an EFP design.
If you see a Javelin or NLAW hit an inert target, it's very modest. If you see a big explosion in a demo it's because they've filled it with fuel!
Javelin is a 50 lbs weapon. Sure, some of that weight is computer and night-vision. But most of that weight difference is explosives (I assume the 2nd tandem charge in particular).
NLAW is 28lbs, somewhere in-between.
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Tandem charges (dual-explosives: first explosion disables reactive armor, second explosion penetrates the tank) basically means carrying 2x warheads with every warhead... its weight and heavy.
Each of those Javelin explosions you see is __TWO__ explosions, timed carefully to defeat Russian reactive armor. Its a sophisticated weapon for sure, but you still have to physically carry all those extra explosives somewhere.
No most of it is the motor. The entire warhead of Javelin weight just 8.4 kg. That's the entire warhead - not just the explosive. An EFP contains a lot of 'inert' metal that gets formed into a projectile.
(Can we not use pounds in a technical military discussion, lol.)
And the entire AT4 weapon (including the sling, the barrel, warhead... everything) is 6.7kg.
Javelin is a big boy. Reaching the limits of what people can carry effectively, especially if you need a 2nd or 3rd shot to do your job.
EDIT: I think RPG7 is like 3kg for the rocket AND explosives, 8.5kg for the entire weapon.
EDIT2: So yeah, you can carry 3x AT4 for the same weight as 1x Javelin.
"just"
So a 'cage device' on top of the turret seems to be intended solely for Javelins, since every other weapon simply won't strike from that direction.
The latter does that by having a steep trajectory. The NLAW just flies horizontally over the tank, then fires down vertically. It also has the other mode where it just hits directly head on.
Kyiv has skyscrapers. A dumb RPG (AT4 or RPG7) fired from the 5th story of a building will hit from the top down... onto the weaker top-armor of a tank.
NLAWs are also top-attack weapons btw.
Once the tanks get bogged down, then anti-tank platoons would be deployed with the heavier gear.
They're a relic since Russia's war in Chechnya where those cages could protect against ancient RPGs fired from buildings in narrow city streets.
[1] https://i.kym-cdn.com/photos/images/original/002/324/004/043...
USA sent IIRC 3x as many "dumb" RPGs (the AT4) as Javelins, assuming that the Ukrainians would be fighting in narrow city streets.
Turned out that urban warfare didn't really happen much. But... I think everyone's plan was for urban combat, and then everybody turned out to be wrong. On the USA side, not a big deal, we sent the wrong mix of weapons but we're fixing that with lend-lease / additional aid packages.
The war isn't really past tense; the swift advance to and battle for Kyiv with the intent of forcing capitulation didn't happen, but as the shift to seizing territory Russia really wants rather than getting handed it by a friendly government imposed on Ukraine has happened, urban warfare has become a thing in Mariupol, and if Russia continues prosecuting the war it’ll probably happen more places.
Other warheads will detonate when they hit the slat armor. With the net result of improved standoff distance. Most warheads don't incorporate enough stand off because it's hard to do so. The extra standoff actually improves penetration.
That said, the AT4 is perfectly usable for side shots, such as in an ambush.
Hitting an enemy fuel truck from 5000m away is a lot safer than running up and shooting it at 200m.
200m shots are common in a city, because cover / concealment is everywhere. Sure, there are still trees and hills to hide in the countryside, but having the option for super long range really helps.
Siege of Mariupol is ongoing since the start of the war. It has seen very brutal urban fighting.
Actually even in 1945 facing Panzerfausts in European cities Soviet tankists tried to similarly bolt/weld onto the top of the turret the spring metal bed frames. It didn't work well if any. While at the same time it showed the precise position of the tank while in bushes, far in the field/etc. Ukrainians have been joking about those "chicken coops" showing the tank position as another sign of a Russian fail and lack of thinking through in this war.
https://old.reddit.com/r/NonCredibleDefense/comments/t9i7q2/...
He posted a good video on his views (and cautions!) on some of this subject matter to date: https://www.youtube.com/watch?v=W9pVEP0AzZ4