Comment on Estonia is digging a 40 km trench to stop Russian tanks — and 600 bunkers are next
Warl0k3@lemmy.world 10 hours ago… Right, which is why I said you’d need to elevate the barrel, my point being that such a maneuver is not a tactical disadvantage.
A small stone wall will stop a Cupra and this ditch sure would be annoying to cross with a bicycle, but while all ditches could be anti-vehicle ditches, very few ditches are anti-tank ditches.
Really though, I’m trying to figure out how to phrase ‘how does physics factor into this’ in a more useful way, because obviously molecules stay together and gravity works, but do you have anything more than that? You can poke a tank barrel through a cinderblock wall without taking it out of battery, it’s a massive tempered steel bar, and barrel obstructions are extremely difficult to get In modern modern tanks, tho iirc not on the T-72, soft barrel obstructions like dirt/mud/water/gravel/etc. can be cleared automatically from the breach controls by diverting pressure from the pneumatics. IIRC the T-72 had to use a squib to achieve the same result, which was stupid dangerous for russian-engineering reasons.
::: spoiler Ps
Buddy that was only evidence for not having to slow, not having to turn the turret. This is starting to feel like you’re just lashing out because your preconceptions are being challenged, not you having a genuine intellectual objection to what I’m saying. You’re clearly unfamiliar with the topic, and you’re butting up against the big dunning-kruger trench (which ironically would make a much more effective tank defense than what’s picture in the OP).
Please just go do a little bit of your own research instead of lashing out with random objections like this, then come back. Even on it’s own it’s a potentially important topic to be familiar with, what with the rise of far right nationalism the world over, and it’s getting clear you don’t have much theoretical (let alone practical) familiarity with the capabilities of AFVs.
Madison420@lemmy.world 10 hours ago
Except that’s again not how physics works, they’re not anti air guns bud. Hull go down = barrel go down and no MBT has 90° of elevation so you turn your turret round just like your own video shows.
Again nothing is going to stop a tank group who wants to get through history has taught us this again and again, all you do is slow them down.
AFVs aren’t tanks btw, if you’re gonna be weirdly tedious about strange stuff you might want to be correct.
Warl0k3@lemmy.world 10 hours ago
Correct: AFVs aren’t tanks, but tanks are AFVs. Using the supercategory in this case is just a nod to actual tanks being pretty rare on a modern battlefield vs. the vast number of tracked armored vehicles.
And also yeah, no argument about gun elevation. Which is why you just go fast over a trench like this, and rely on it being < 1/2 the length of your vehicle (ex: the T-72 has a ground support length of around 9m for this roughly 4m trench) for added stability while crossing. Which totally ignores that you’d only get to where a 90° elevation would be relevant if you go so slow you’re pointing directly down into the trench, which wouldn’t happen if you impacted the angled far wall (which is why real tank ditches are shaped like the dunning kruger graph or the trench in the vid I linked - a sharp vertical wall to prevent climbing combined with an angled ramp to direct the bulk of the tank downwards before it’s feasible for the gap to be jumped)
Keep in mind that tanks initially existed for the sole reason of crossing tanks like this. While warfare has evolved and tanks no longer have WWI / Warhammer style gigantic climbing tracks, the basic use of a tank as an obstacle-crossing fire support vehicle has not changed.
Madison420@lemmy.world 8 hours ago
crust.piefed.social/comment/151494
It’s specifically a question about a tank.
No you don’t, you might fast and turn the turret around like the video shows but you’re not going to plow into a dirt wall and foul your barrel if you don’t have to.
I really shouldn’t have to draw a picture to show you if your front end goes 35° hull down just to stay level with level terrain you’d need 55° up elevation. In this case there’s another ridge that’s probably 40° so add 40 to 55 and you get? Anyone? Anyone ? 95°! And we just agreed no MBT has 90° up elevation so the only possible thing you could be proposing would be that tank crews are going to en masse heave themselves into a wall they know their barrel will impact and likely foul in rather then turn the turret and cross to the other side where you can then use your tracks to move the dirt in the hill back into the pit so it’s whole again.
I’d say that’s absurd but maybe in this administration bugs bunny operates a no holds barred tank division but I dunno I guess I don’t keep up with the news enough.
Warl0k3@lemmy.world 7 hours ago
Aight so that was sad enough I figured I’d do a couple physical sims just to answer the question definitively:
turns out a T72 would need +35° of elevation to clear this if you approached at 1kph
Image
But at +14° elevation, it'll just barely clip the top at 30kph
Image
And only needs to be going ~46.02kph to clear the berm
Image
But to cross at 30mph, you’d only need to rotate the barrel ~20° off center-line to clear the berm (which if Warthunder is to be believed (hehe), will take 5/8^ths^ of a second to return to axial - this is as close as I could get to the actual figure but it’s probably closer to a full second, I couldn’t find acceleration curves for the T-72 turret traversal (go figure)).
So you’re right, most likely a T-72 crew would have to rotate the turret some to clear this berm unless they’re going flat-out across that field, which is possible for them to achieve but the offroad speed of the T-72 isn’t super reliably reported (again go figure) so lets just go with you’re right.
And with that side topic settled, back to my point: this ditch ain’t going to force an AFV to slow down. Like at all.
Disclosures:
I used the absolute shortest value for ground support length which is only 5.5m, used the common 106" ditch crossing value for ease instead of calculating it custom as soil dynamics sucks to define, used the most generous estimate I could for ditch dimensions (4m wide w/ 90° slopes) and just traced the outline of a T72 where I couldn’t find specific dimensions in the manual I’ll pretend I have sitting on my desk but which I just googled around to find, and I also just totally ignored ground compression for the same reason (but eyeballing it, it should roughly even out)