Comment by themodelplumber | Hacker News Reader

Comment by themodelplumber | Hacker News Reader

themodelplumber

> obvious requirements for a future anti-armor weapon for urban combat is a low-signature, multi-shot, recoil-attenuated, light-weight weapon which can be fired from inside enclosures

This is really interesting to think about. The first thing that comes to mind is this method from WW2:

"Another method used by the British Home Guard in 1940 was to place dynamite or some other high explosive in a thick sock and cover the lower part with axle grease and then place the grease covered part in a suitable size tin can. The antitank sock was pulled out, the fuse lit and the sock thrown against the side of the tank turret in the hope it would stick until the explosion. If successful, it caused internal spalling of the armor plate, killing or injuring the tank crew inside" [1]

An adaptation of that method, if it could be applicable, seems more amenable to differing means of propulsion, possibly solving the issues: low-signature, multi-shot, recoil, and light-weight.

A greasy-sock-gatling-cannon? Something else? One never knows, but it's pretty intriguing to see a general specification for the next evolution of anti-tank.

1. https://military-history.fandom.com/wiki/Anti-tank_grenade

modern armor is incredibly resistant to spalling. HESH rounds, the high-tech version of sticky dynamite, have fallen out of favor in preference to kinetic penetrators and shaped charges.

the hardest part of applying anti-tank munitions to a tank is getting close to the tank. so, they're generally projectile weapons.

man-portable devices have size and recoil limits that immediately rule out kinetic penetrators.

shaped charges work at lower velocity, but are massive and conical, so they mostly have to be rockets fired from a recoilless launcher.

there has probably been some work trying to deliver shaped charges via drone to reduce launch signature, but that would be much slower, more costly, vulnerable to active defenses, and vulnerable to electronic countermeasures.

eventually if your drone is small and fast enough, it's a missile, and if it's big enough to launch from out of reach, you just launch it from an airfield, and we already do both of those.

As demonstrated in the motion picture “saving private Ryan”

For anyone curious (the scene):

https://www.youtube.com/watch?v=KLUJsyN7AYg

A small drone places a

dynamite stick at a

vulnerable spot

Edit: spacing

OK not to be funny, but that is so close to being haiku.

You mean like what we saw in Iraq against US armor, etc.?

Your wish is my command. (Haikus don't have to have exact syllable counts) This will be my last post on hn ever.

Too true! End the syllable regime! I love it. Plz stay

so much depends

upon

a red wheel

barrow

glazed with rain

water

beside the white

chickens

A closer look at video footages by DAESH reveals that the bombs dropped by drones are not as effective as vehicle-bombs since 40 mm munitions have limited effect. However, a drone with the help of a simple mechanism can still inflict casualties on ISF personnel or cause the injury of personnel and render them ineffective in the fight.

Page 36: https://setav.org/en/assets/uploads/2017/08/Report88.pdf

That might work in 1950. Nobody is bum rushing a modern tank. Well someone might, but they ain't living to talk about it. Modern tanks are too well integrated with mechanized infantry and their visibility is too good to be surprised by a man delivered explosive device. I mean you might get away with it in downtown Fallujah where you only need to rush 10yd but it'll take you three dozen bodies trying before you get a single mobility kill.

You wanna kill a modern tank, plant an IED in the street and wait.

Ah, but they covered those contingencies in the article. Multiple teams, a machine gunner on the team to take out infantry, channelized environments with e.g. basement cover, and location research.

It all comes down to numbers. How many bodies, how much explosives, etc. can you afford per tank?

What? Tanks are blind. Without infantry support up close they are less effective.

Based on the antitank Twitter thread going around, the IED is optional.

It sounds like a good ol pitfall trap is all you need, which apparently can be made by just removing road signs, so that the tank might drive into a poorly supported road, collapsing into the sewer under the street.

You'd likely need shaped charges or thermite (on a flat surface) instead of dynamite.

Thermite wouldn't be too hard to, would it? Potassium permanganate and glycerine can be used to start the reaction among the metal shavings reliably with a small (~2 sec) delay.

It could be tough to manufacture the components if they aren't available. Magnesium is a more reliable way to ignite it.

Both of those are readily available at drug stores, I'd find magnesium ribbon a bit harder to get, honestly, though I don't know how that changes at commercial scale.

What do they have potassium permanganate for at the drug store? I didn't think they had it.

Sorry, that one is a fish tank cleaner, but still easily available.

The British PIAT from WW2 kind of fits that description. https://en.wikipedia.org/wiki/PIAT

How to deliver something like this from a distance?

https://en.wikipedia.org/wiki/RKG-3_anti-tank_grenade

RPG 7 grenade can be modified to remove the failsafe, and attached on a long, 5 meters+ stick.

RPG 7 piezodetonator normally needs 30G-40G acceleration to arm. https://www.armedconflicts.com/attachments/11561/14_-_Pancie...

5 meters! Fascinating. Is this for anti-tank? Does removing the failsafe mean disabling some kind of projectile distance-sensing tech or what?

Just...reach...a...little...closer (shields important parts of body)

> some kind of projectile distance-sensing tech

I'd assumed it would be a timer.

The mechanism varies with the warhead. The PG-7 uses the acceleration from launch to set off a primer. This starts a slow fuse that will cause self-destruct if the grenade doesn't hit a target within a few seconds (so you don't have a live warhead cluttering up the place, requiring an EOD team to dispose of it.) It also burns away a safety plunger that allows the piezo-impact fuze to complete it's circuit and ignite the shaped-charge.

So to get one to detonate manually, you're going to have to simulate the 40-ish Gs of a launch, the delay of flight to allow the safety to disengage (but not so long that the self-destruct happens), and be far enough away to not get injured by the explosion. That's a challenge.

The safety bypass on PG 7 only requires a piece of wire to connect detonator around the safety, or removal of pyrotechnical spacer with basic tools.

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