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-   -   Can a 20mm cannon penetrate the sidal armour of an M1 Abrams? And other questions. (http://boards.straightdope.com/sdmb/showthread.php?t=809219)

Archinist 11-01-2016 08:22 AM

Can a 20mm cannon penetrate the sidal armour of an M1 Abrams? And other questions.
 
I am wondering how effective a 20mm AP cannon would be against the sidal armour of an M1 Abrams original. How about a .50 caliber gun against the rear ventilation port of an Abrams? What about with AP sabot rounds?

Not just bullets either. How badly would pouring boiling oil from a medieval castle wall damage a modern MBT? Or what about throwing a large rock at it from a catapult?

Could you detonate a HE shell inside it's barrel by shooting at it down the barrel? Or stabbing it with a knife? Can you damage the barrel itself by shoving a knife down inside? I read that this is possible on a Quora post with 80 or so upvotes.

bump 11-01-2016 10:48 AM

Pretty sure a 50 cal machine gun isn't liable to do much to a M1, except mess up the optics.

A 20mm gun isn't liable to do much to the side armor; even the vaunted 30mm Avenger cannon only penetrates 76mm at 300m, and it's designed to kill tanks. A 20mm round probably does less damage at the same range, and the M1 probably has more than 76mm worth of protection from the side.

Boiling oil probably wouldn't do much unless you lit it, and then it would effectively be the same as a molotov cocktail.

A rock wouldn't do much, even if fired from a trebuchet.

I suppose you could mess up a shell and the barrel, but I dont' think you'd kill the tank unless you got lucky and rolled your grenade down the barrel as they opened the breech.

Kelevra 11-01-2016 10:51 AM

The wikipedia article on the M1 Abrams has some pretty interesting reading on damage to various tanks, the causes, and the results. https://en.wikipedia.org/wiki/History_of_the_M1_Abrams

A 20 mm cannon would not penetrate the side armor. While there have been a huge number of 20 mm cannons through the years, none of them offer that sort of penetration. WWII cannons with specialized ammunition might penetrate 40 mm of armor. http://www.panzerworld.com/armor-penetration-table

AndrewL 11-01-2016 10:59 AM

... need answer fast?

snfaulkner 11-01-2016 05:34 PM

While we're being crazy here, how about thermite? Will it melt through chobham?

DinoR 11-01-2016 07:22 PM

Quote:

Originally Posted by Archinist (Post 19743886)
Could you detonate a HE shell inside it's barrel by shooting at it down the barrel?

The fuse isn't active when it's in the barrel so simply hitting the fuse isn't enough at that point. Despite the fuse being at the tip (and other places like on the 120MM MPAT) the detonators aren't. Short of hitting the detonator I wouldn't bet the impact from a small arms round is enough to cause it to explode. Also unless the gun is pointing directly at you the round is likely bouncing on it's way down the barrel further reducing the energy. If it's not concentrating on a target they are about to engage, the barrel is moving around too if they are at all expecting a threat.

Put the last two points together. You really only have a decent shot to try when the barrel is pointing directly at you and the tank is about to engage.

Quote:

Or stabbing it with a knife?
Is your name Mister Fantastic? Do you have a similar super power? If not your arms aren't remotely long enough to stab the round.

Quote:

Can you damage the barrel itself by shoving a knife down inside? I read that this is possible on a Quora post with 80 or so upvotes.
I'm not sure that any knife you'll likely have is harder than the surface hardness inside the barrel. The grooves of the rifling are quite a bit deeper than any small scratch you'd get in quickly anyway.

Leaving it inside might work. Something like jamming the tube into mud fully obstructing the barrel tends to result in the barrel needing replacing if the crew fires before cleaning it out. I'm not sure something as small as a knife would be a big enough obstruction. Feel free to try. Be aware the crew will still have a tank that, other than the main gun, is probably fully functional. That crew will be pissed. Not as pissed as if you shot their cooler and sleeping bags up but still... :D

JerrySTL 11-01-2016 08:38 PM

While a single 20 mm round probably wouldn't do much harm, I wonder about multiple impacts at the same spot? Many aircraft can shoot hundreds of rounds a minute. Of course the tank and aircraft are probably both moving (especially the aircraft) so hitting the same spot more than once could be problematic.

Banksiaman 11-01-2016 09:33 PM

Quote:

Originally Posted by bump (Post 19744295)
...

A rock wouldn't do much, even if fired from a trebuchet.

...

But what if the TANK was thrown by a trebuchet and it flew and tumbled waaaaaaaay away, and landed on its tracks? I don't fancy the crews' chances, but could the tank survive that?

Is the impact of that qualitatively different from a nearby explosion (e.g. neighbouring tank blown up by pouring coke and Mentos down barrel)?




Straight Dope - tackling the big questions.

snfaulkner 11-01-2016 09:40 PM

Quote:

Originally Posted by Banksiaman (Post 19745962)
But what if the TANK was thrown by a trebuchet and it flew and tumbled waaaaaaaay away, and landed on its tracks? I don't fancy the crews' chances, but could the tank survive that?

Is the impact of that qualitatively different from a nearby explosion (e.g. neighbouring tank blown up by pouring coke and Mentos down barrel)?




Straight Dope - tackling the big questions.

I'm trying to imagine a trebuchet capable of throwing a 60+ ton projectile waaaaaaaay away.

Tamerlane 11-01-2016 09:43 PM

Quote:

Originally Posted by Banksiaman (Post 19745962)
But what if the TANK was thrown by a trebuchet and it flew and tumbled waaaaaaaay away, and landed on its tracks?

Man I'd like to see the trebuchet capable of hurling over 60 tons of tank. The counterweight alone would have to be...what...minimally 2,400 tons and probably closer to 6,000 :eek:?

Asuka 11-02-2016 02:41 AM

Quote:

Originally Posted by JerrySTL (Post 19745843)
While a single 20 mm round probably wouldn't do much harm, I wonder about multiple impacts at the same spot? Many aircraft can shoot hundreds of rounds a minute. Of course the tank and aircraft are probably both moving (especially the aircraft) so hitting the same spot more than once could be problematic.

During the early stages of the Eastern Front of World War 2 German 37mm anti-tank guns were completely incapable of penetrating the armor of Soviet T-34 tanks, to the point that one of the Soviet T-34 strategies of dealing with 37mm AT guns was to simply charge them and run them over to conserve ammo since they offered no threat to them. KV-1 heavy tanks also reported incidents where hundreds of 37mm rounds hit them frontally or on the side and the tanks were completely fine. Since modern tanks have many times the protection of those tanks I doubt multiple 20mm hits would do any damage at all except maybe from the very top.

muldoonthief 11-02-2016 07:28 AM

Quote:

Originally Posted by bump (Post 19744295)
A rock wouldn't do much, even if fired from a trebuchet.

Are you sure? Tank armor is designed to protect against HEAT and sabot rounds. A large rock is a very different attack. According to wikipedia, the largest trebuchets could launch a 90 kg rock up to 300 meters. That's an impact velocity of 54 m/s or 120 mph. I wouldn't be surprised if having 200 lb of rock hitting the top of a tank at 120 mph did a lot of damage.
Quote:

Originally Posted by DinoR (Post 19745680)
I'm not sure that any knife you'll likely have is harder than the surface hardness inside the barrel. The grooves of the rifling are quite a bit deeper than any small scratch you'd get in quickly anyway.

The Abrams has a smoothbore main gun. Not that it matters - you're not going to be able to do anything to the bore with a knife that will affect it.

Quercus 11-02-2016 08:35 AM

Quote:

Originally Posted by muldoonthief (Post 19746464)
Are you sure? Tank armor is designed to protect against HEAT and sabot rounds. A large rock is a very different attack. According to wikipedia, the largest trebuchets could launch a 90 kg rock up to 300 meters.

That 90kg is only the summary:

Quote:

Originally Posted by Wikipedia
In 1421 the future Charles VII of France commissioned a trebuchet (coyllar) that could shoot a stone of 800 kg, while in 1188 at Ashyun, rocks up to 1,500 kg were used.

Now we're up to 1.5 tons. Which is a lot less than an 60-ton tank, but the falling impact is going to be a lot more than 1.5 static tons.

I'm no expert, but my wild guess is that a direct hit wouldn't smash the tank flat, but it would have a good chance of messing up the turret bearings, suspension/treads, gun barrels (main and machine), and anything else sticking out of the main armor box.

Gray Ghost 11-02-2016 08:36 AM

Quote:

Originally Posted by Archinist (Post 19743886)
I am wondering how effective a 20mm AP cannon would be against the sidal armour of an M1 Abrams original...

...What about with AP sabot rounds?...

...Or stabbing it with a knife? Can you damage the barrel itself by shoving a knife down inside?...

Quote:

Originally Posted by DinoR (Post 19745680)
...I'm not sure that any knife you'll likely have is harder than the surface hardness inside the barrel. The grooves of the rifling are quite a bit deeper than any small scratch you'd get in quickly anyway...

Quote:

Originally Posted by muldoonthief (Post 19746464)
...A large rock is a very different attack. According to wikipedia, the largest trebuchets could launch a 90 kg rock up to 300 meters. That's an impact velocity of 54 m/s or 120 mph. I wouldn't be surprised if having 200 lb of rock hitting the top of a tank at 120 mph did a lot of damage.

The Abrams has a smoothbore main gun. Not that it matters - you're not going to be able to do anything to the bore with a knife that will affect it.

Surface hardness of the M1A2's M256 120mm L/44 gun's chrome plated lining is currently (?) around 900-1100 on the Knoop hardness scale. As chrome plating, and specifically hexavalent chrome waste, leads to a bit of a toxic waste issue, the US Army is investigating other methods of surface treatment for large gun barrels like the M256. One of those methods involves sputtering either Tantalum or Chromium onto the surface of those barrels. Measured hardness from either of those sputtered materials is around 200 Knoop (or HK), which is evidently hard enough for the purpose. (See Slide 18 of the linked document.) Without this coating, ultra-high speed kinetic energy penetrator shells like the M829A3 would wear out the barrel in, ballpark, about 150 shots. (Slide 3) FWIW, the A3 looks to be much rougher on the barrel than other ammunition. 5700 FPS comes with a price.

Anyway, kitchen knives' hardnesses are often measured on the Rockwell C scale. 55-60 is typical, though modern powdered metal blades can get higher. Converting between the two scales shows that 55-60 HRc is about 600-700 HK. So, I don't think the knife would scratch the older barrels, but it might scratch the newer sputtered ones.

As to penetrating the armor on a modern MBT with multiple smaller impacts, I'll link to this oldie-but-goodie, the A-10 Pilot's Coloring Book, circa 1977. Not because it's all that helpful in answering the question, but it does show that answering "will it penetrate or not?" really depends on where the tank is struck. I have read accounts from Bradley crew that they were able to penetrate the armor on T-72 on down with 25mm sabot ammunition and judiciously selecting where to shoot the tank. I haven't read of sabot ammunition available for the 20mm x 102 rounds the U.S. M61 rotary cannon uses. Which strikes me as strange, given sabot AP ammunition exists for smaller cartridges like 12.7 and 7.62 mm. I wonder if it's because 20mm is primarily an aircraft or anti/aircraft weapon for the U.S., and sabots are either unneeded to damage aircraft, or pose a FOD hazard when shot from aircraft?

Moreover, sabot ammunition isn't the most friendly to use in a combined arms environment; flying sabot petals evidently pose quite the risk to infantry operating in front of the gun muzzle. (Range safety document, with more info than probably you want on surface danger zones for a large variety of ammunition. From it, at page 98, even plastic sabots from 25mm shells are dangerous up to 100m downrange, and up to 50 m to the side of the muzzle.) Still, if you need to punch through armor, there's no substitute for speed, and sabot rounds are faster than everything else.

As far as the trebuchet and rock go, don't tanks often knock down trees while maneuvering in forests? Are tanks often damaged by tree tops falling onto their top armor?

muldoonthief 11-02-2016 09:10 AM

Quote:

Originally Posted by Gray Ghost (Post 19746601)
As far as the trebuchet and rock go, don't tanks often knock down trees while maneuvering in forests? Are tanks often damaged by tree tops falling onto their top armor?

The treetops aren't moving at 120 mph, and aren't nearly as rigid as a rock.

But here's a cool video of an M1 knocking down trees.

GreedySmurf 11-02-2016 10:00 AM

Quote:

Originally Posted by Quercus (Post 19746597)
That 90kg is only the summary:

Now we're up to 1.5 tons. Which is a lot less than an 60-ton tank, but the falling impact is going to be a lot more than 1.5 static tons.

I'm no expert, but my wild guess is that a direct hit wouldn't smash the tank flat, but it would have a good chance of messing up the turret bearings, suspension/treads, gun barrels (main and machine), and anything else sticking out of the main armor box.

The rock would definitely not do any damage to the armour itself. Back of the Envelope calculations only, but the 1.5 ton rock would impact with ~2,000 Kj of kinetic energy. A modern sabot round I believe delivers in excess of 12,000 Kj of kinetic energy. Which depending upon where you hit it, an M1 can shrug off.

As you suggest, some of the components might suffer, and I suspect a shaken up crew, but good luck hitting a mobile target like a tank with a trebuchet anyway. :D

carnivorousplant 11-02-2016 10:04 AM

Quote:

Originally Posted by Banksiaman (Post 19745962)
tank blown up by pouring coke and Mentos down barrel



Straight Dope - tackling the big questions.

Mentos and Coke-all bets are off.

carnivorousplant 11-02-2016 10:07 AM

Quote:

Originally Posted by Tamerlane (Post 19745981)
Man I'd like to see the trebuchet capable of hurling over 60 tons of tank. The counterweight alone would have to be...what...minimally 2,400 tons and probably closer to 6,000 :eek:?

What if the trebuchet were on a conveyor belt?

Corry El 11-02-2016 10:16 AM

Quote:

Originally Posted by Gray Ghost (Post 19746601)
I haven't read of sabot ammunition available for the 20mm x 102 rounds the U.S. M61 rotary cannon uses. Which strikes me as strange, given sabot AP ammunition exists for smaller cartridges like 12.7 and 7.62 mm. I wonder if it's because 20mm is primarily an aircraft or anti/aircraft weapon for the U.S., and sabots are either unneeded to damage aircraft, or pose a FOD hazard when shot from aircraft?

20mmx102 APDS rounds exist; they are the standard ammo for the 20mm Gatling gun as used in the Phalanx shipboard terminal missile defense system. They aren't used in a/c guns for the reason you stated. In a few freak cases modern fighters have managed to fly into the path of their own 20mm projectiles, not to mention a cloud of sabot petals rapidly decelerating in the a/c's path.

Anyway even with a stationary gun against a stationary target, there is enough dispersion in the trajectory from round to round to make it unlikely to hit 'the exact same spot' (say we define that as a difference of some small % of the round's diameter). And Gatling guns have a larger dispersion when the barrel is moving perpendicularly to the axis of fire at a varying speed as the gun spools up at the beginning of a burst (eventually it's constant and can be corrected for by the same degree on each shot). Some dispersion is fine; the optimum dispersion is generally greater than zero in multiple rounds against a moving target, but hitting right on top of a previous hit is not likely.

In some actual cases though antitank rounds defeated armor they were theoretically incapable of penetrating by nearby hits causing the armor to shatter. You can find pictures of armor of German tanks in WWII defeated that way by theoretically overmatched Allied antitank rounds. Of course it also might have meant the armor wasn't produced correctly. And it's not directly relevant to modern tanks where protected by heterogeneous armor arrays rather than steel plates.

The highest penetration performance quoted for any 20mm rounds are for 20x139 APDS types as fired by the Rheinmetall Rh202 on for example the German Marder Infantry Fighting Vehicle. That's 60mm per the Wiki page, 44mm at 1000m by other sources.

The lowest value I could find for M1 armor is from a Russian site's diagram showing only 30mm of steel on the lower hull side behind/beneath the skirts, and also meaning the round has to thread its way through the closely spaced road wheels. And it's just somebody's official looking diagram of classified info.
http://i.imgur.com/x6DM0PT.jpg
This Steel Beasts game specification shows a very narrow zone of 50mm protection just below the side skirts
http://www.steelbeasts.com/sbwiki/im...HA_sideLOS.jpg

But in both regards, penetration and protection, there's now a parallel world of values programmed into games which the game programmers *try* to verify in the real world, but they must come up with some detailed specification either way. The game values are often the product of discussion among people who know what they are talking about, in general technically, but who aren't divulging classified info. It's not necessarily crudely made up stuff by people with no idea what they are talking about. Many such learned discussions occurred over the years here for example, though this forum is not what it used to be:
http://www.tank-net.com/forums/index.php?act=idx
(somehow the site also now generates an unsafe site warning. I've never had a problem, but I'm not telling anyone to proceed to it if not comfortable doing so)
Anyway, these numbers are people's estimates, possibly in some cases actual info which has leaked, but I'm not saying it's the absolute fact, and I'd recommend against people who know it's not correct from their own knowledge of classified info speaking up and saying so, even just to say that.

Practically speaking 20mm guns have negligible capability v modern well protected tanks. US claims against Iraqi tanks in 1991 even with 25mm in side shots is not to my knowledge solidly documented. There's a surprising lack of detailed public info on actual weapons effects and causes of Iraqi tank losses after all this time, besides certain well known photos which speak for themselves.

DinoR 11-02-2016 12:36 PM

Quote:

Originally Posted by muldoonthief (Post 19746464)
The Abrams has a smoothbore main gun. Not that it matters - you're not going to be able to do anything to the bore with a knife that will affect it.

I was just coming back to mention that since I had both slicks and A1s (and later) floating through my head based on the OP. I defaulted to the gun all my Table VIIIs were on.

DinoR 11-02-2016 01:41 PM

Quote:

Originally Posted by Gray Ghost (Post 19746601)
As far as the trebuchet and rock go, don't tanks often knock down trees while maneuvering in forests?

From personal experience, yes.

Quote:

Are tanks often damaged by tree tops falling onto their top armor?
No. I never saw any damage to the tank from falling trees.

If you are doing it right, they mostly don't fall on you anyway. Hit them slow enough with he center of the front slope and you more push them over/away. It happens though. Especially if things are thick because they can hit trees behind them and bounce back towards you. The tree that landed on my head pulled that deception. Fortunately it didn't hit me someplace vital. :D

There was a variety in a few of our training areas that tended to break off higher. The lower trunk on those would push away but the tree tops were like spears of doom hurled straight down onto the top armor by tree gods angry at tanks challenging their supremacy. That didn't affect the tank either. It WAS scarier.

I did, once, mildly bend a couple of the fins on the grill over my exhaust (M1 slick). I did it by ramming into two closely set trees at high speed going backwards. ("Driver hold left!!!! *SMASH* "Driver stop...your other left.) Admittedly one was dead but still standing. That one just exploded into sawdust and splinters. The living tree left chunks we had to pick out and some inconsequential bending to a couple fins. Going forward, taking a tree on the track tended to bend up the fender. It happened more when you were trying to weave in and around the trees to save them. That didn't affect function. Well the left fender was a nice sleeping spot when I was still on the M60A3; not making a nice bed lumpy is kind of functional. :p

muldoonthief 11-02-2016 01:41 PM

Quote:

Originally Posted by GreedySmurf (Post 19746822)
The rock would definitely not do any damage to the armour itself. Back of the Envelope calculations only, but the 1.5 ton rock would impact with ~2,000 Kj of kinetic energy. A modern sabot round I believe delivers in excess of 12,000 Kj of kinetic energy. Which depending upon where you hit it, an M1 can shrug off.

As you suggest, some of the components might suffer, and I suspect a shaken up crew, but good luck hitting a mobile target like a tank with a trebuchet anyway. :D

You can't just go by KE though. Dropping a Nimitz class aircraft carrier from a height of 2mm onto an Abrams would also be about 2000 kJ, but I'm guessing the Abrams wouldn't drive away from it.

Even if the rock didn't penetrate the armor, the momentum of something so large would probably be a mission kill - if it hits the cannon, that's toast, if it hits the turret, it will probably damage it enough that it couldn't rotate anymore, would probably destroy any road wheels it hit, etc.

I totally agree with the difficulties of hitting a tank from a trebuchet though.

swampspruce 11-02-2016 05:21 PM

Defilade the trebuchets and set for a wide dispersion! If we get enough rocks in the air he can't take us all out....

barath_s 11-03-2016 09:01 PM

Quote:

Originally Posted by carnivorousplant (Post 19746838)
What if the trebuchet were on a conveyor belt?

What if the trebuchet were on a plane that was on the conveyor belt

Melbourne 11-03-2016 09:50 PM

Quote:

Originally Posted by Banksiaman (Post 19745962)
But what if the TANK was thrown by a trebuchet and it flew and tumbled waaaaaaaay away, and landed on its tracks? I don't fancy the crews' chances, but could the tank survive that?

Is the impact of that qualitatively different from a nearby explosion (e.g. neighbouring tank blown up by pouring coke and Mentos down barrel)?

Straight Dope - tackling the big questions.

IN Aus the tank that preceded the Abrams was the Leopard (a German design).. I don't know anyone who tried the Mentos thing, but I do know that one of the Leopards was disabled by an arrow, shot into the turret bearings. With the barrel stuck out sideways, it's difficult to manoeuvre through trees

Chronos 11-04-2016 06:12 AM

What about reactive armor? As I understand, that works by blowing pieces of itself away. What would it take to trigger the armor to react unnecessarily, and how many hits of that to completely remove the reactive layer?

Which would still leave the considerable inert armor underneath, of course, but it might at least leave the tank vulnerable to other weapons.

carnivorousplant 11-04-2016 07:39 AM

Quote:

Originally Posted by barath_s (Post 19751113)
What if the trebuchet were on a plane that was on the conveyor belt

A plane with snakes aboard!

Lumpy 11-04-2016 08:09 AM

Somewhat related previous thread:

Minimum weapon to damage an Abrams tank?

Whiskey Dickens 11-04-2016 08:23 AM

Great responses, DinoR, Gray Ghost and Corry El!

Always love unca Dino's Abrams storytime. Keep 'em coming!

Jophiel 11-04-2016 08:44 AM

I don't have an answer for the OP but on November 1st I was ALSO Googling whether or not a tank could be taken out with a catapult about an hour before this post came up. Which makes me wonder what was going on Nov 1st to put that thought into both our heads.

DesertDog 11-04-2016 09:00 AM

Quote:

Originally Posted by snfaulkner (Post 19745977)
I'm trying to imagine a trebuchet capable of throwing a 60+ ton projectile waaaaaaaay away.

Truly. Last year the Department of Public Works at Burning Man fired a flaming piano* from a treb and the distance was . . . unimpressive.

*Not really shown in the video is the squad jumping on the debris to clean up the mess; it took them seven minutes.

Channing Idaho Banks 11-04-2016 09:11 AM

Do tanks actually use sidal armor or is the OP just making that up?

bump 11-04-2016 09:22 AM

Quote:

Originally Posted by muldoonthief (Post 19747458)
You can't just go by KE though. Dropping a Nimitz class aircraft carrier from a height of 2mm onto an Abrams would also be about 2000 kJ, but I'm guessing the Abrams wouldn't drive away from it.

Even if the rock didn't penetrate the armor, the momentum of something so large would probably be a mission kill - if it hits the cannon, that's toast, if it hits the turret, it will probably damage it enough that it couldn't rotate anymore, would probably destroy any road wheels it hit, etc.

Sure, but the crews are what count; all the tanks, airplanes, etc... in the world don't matter if you don't have trained crews to put in them.

Enilno 11-04-2016 09:49 AM

If I can approach the question from the other direction, how fast would a round from say, the M61 Vulcan, which wiki says weighs 102.4 g, have to be traveling to be able to defeat the armor. I assume if you can put enough kinetic energy into the round that at some point it'll be enough.

Mr Quatro 11-04-2016 10:08 AM

Does the tank in question have electronics on board? It's just a matter of time before they invent a hand held EMP rifle.

This article is only two (2) weeks old:
http://mil-embedded.com/news/raytheo...-research-lab/

Quote:

Boeing has announced that it successfully tested an electromagnetic pulse missile capable of disabling electronics without affecting structures. The Counter-electronics High-powered Advanced Missile Project (CHAMP) was tested by a Boeing Phantom Works/U.S. Air Force Research Laboratory Directed Energy Directorate team on October 16 at the Utah Test and Training Range.

muldoonthief 11-04-2016 11:50 AM

Quote:

Originally Posted by bump (Post 19751975)
Sure, but the crews are what count; all the tanks, airplanes, etc... in the world don't matter if you don't have trained crews to put in them.

In the long run, sure. But in the middle of a battle, rendering an enemy tank unusable is good enough for now.

Gunslinger 11-04-2016 07:32 PM

Remember, though, the armor's thinnest on the top, so a sufficiently big artillery shell (or trebuchet-flung rock) will splat a tank like a bug.

But if the rock hits the side (good luck aiming a trebuchet at a fast-moving vehicle, though) and knocks off a track, well, now it's a pillbox that still has 3-4 heavy machine guns (with longer range than the trebuchet) and one REALLY BIG gun (and probably at least several rounds each of HE and canister, in addition to the lawn darts). And they're going to be extremely angry at the trebuchet crew. Better hope the second rock-flinger in the battery has better aim.

Tangent:
Quote:

Originally Posted by muldoonthief (Post 19752358)
In the long run, sure. But in the middle of a battle, rendering an enemy tank unusable is good enough for now.

Yeah, but not all that great if they get it back and fix it (or the crew bailed, and climb back in once you move on to find the interior damage isn't as bad as they thought/hose out what's left of the driver) and continue on as soon as you drive away. There's a reason one of the big rules of antitank gunnery has traditionally been "keep shooting it until it burns or explodes." Especially if there's a chance you may not end up holding the ground at the end of the day.

There was one M1 temporarily knocked out during Desert Storm (penetrating hit of "unknown origin*" killed or seriously injured the driver, IIRC, but no major damage to the tank itself aside from a hole in it). They sent the casualty back to collect his Purple Heart and kept going for two or three weeks with just three crewmen, until somebody happened to walk by the tank with a Geiger counter and realize it was hot as hell, and not in the sun-baked sense. :eek: Turns out, whatever had hit it had filled it with mildly radioactive dust.

Fun fact: tank crewmen start as a driver, then train to become a loader, loader trains on how to work the gun, gunner learns to be a commander as they advance up the ranks, that way if somebody gets knocked out, the next guy up can cover his position, the guy above that covers that guy's, and the commander does double duty as gunner. (And I guess if the CDR gets whacked the gunner gets a promotion.)

(*-- i.e., they never found out which of its platoonmates the shot came from; there's not much that'll get through the front of an Abrams, and only one thing that's radioactive)

Precambrianmollusc 11-05-2016 09:02 PM

Quote:

Originally Posted by GreedySmurf (Post 19746822)
T

As you suggest, some of the components might suffer, and I suspect a shaken up crew, but good luck hitting a mobile target like a tank with a trebuchet anyway. :D



But if the tank is on a treadmill?


.

Precambrianmollusc 11-05-2016 09:22 PM

Quote:

Originally Posted by Gunslinger (Post 19753346)
Remember, though, the armor's thinnest on the top, so a sufficiently big artillery shell (or trebuchet-flung rock) will splat a tank like a bug.




The question here though is 'what is sufficiently big?' . Clearly by definition anything that is 'sufficiently big' will do what it is sufficient for .




.

drachillix 11-05-2016 10:56 PM

Quote:

Originally Posted by barath_s (Post 19751113)
What if the trebuchet were on a plane that was on the conveyor belt

The rock flies

bump 11-07-2016 08:45 AM

Quote:

Originally Posted by Gunslinger (Post 19753346)
Fun fact: tank crewmen start as a driver, then train to become a loader, loader trains on how to work the gun, gunner learns to be a commander as they advance up the ranks, that way if somebody gets knocked out, the next guy up can cover his position, the guy above that covers that guy's, and the commander does double duty as gunner. (And I guess if the CDR gets whacked the gunner gets a promotion.)

I always thought the loader was the lowest guy on the crew totem pole. as loading the gun and manning a mg is a little less skilled than actually driving the tank.

Chronos 11-07-2016 09:22 AM

Can the top-ranked guy in the tank change the duties around if he wants? A cousin of mine is a tanker, and has made his way up to fairly high rank (Lt. Col., from what I'm told), so I'm presuming that he would be the boss in any tank he's in... but that cousin absolutely loves to drive, and is quite good at it. Would it be allowed/acceptable for him to just say to the low man on the totem pole "Move over; I'm taking the wheel" (or whatever it is that a tank has)?

muldoonthief 11-07-2016 10:58 AM

Quote:

Originally Posted by Chronos (Post 19758497)
Can the top-ranked guy in the tank change the duties around if he wants? A cousin of mine is a tanker, and has made his way up to fairly high rank (Lt. Col., from what I'm told), so I'm presuming that he would be the boss in any tank he's in... but that cousin absolutely loves to drive, and is quite good at it. Would it be allowed/acceptable for him to just say to the low man on the totem pole "Move over; I'm taking the wheel" (or whatever it is that a tank has)?

A Lt. Col. deciding to drive his own tank would be like a destroyer captain heading down to the engine room because he likes to watch gauges. He'd probably get away with it because no one is there to tell him no, but if anything goes wrong because he was goofing off instead of doing his actual job (battalion commander maybe?) his career would be well and truly screwed.

Archinist 11-07-2016 12:55 PM

So that means that a medieval army could wage a reasonably decent battle against a similar-sized modern army? All they have to do is dog holes in the ground, put leaves over them, and wait for the tanks go fall down the holes.

To prevent any artillery from firing at their important areas, they could just kidnap a civilian group and put them in the area so that artillery and bombs can't be fired at them.

Then they could build fake helicopter landing pads on the ground which look like normal landing pads but are actually mined out with greek fire and gunpowder. Then they can wait until the helicopters land on it and set it on fire.

To prevent the infantry mens to invade the country, they could just dig randomly-placed pits filled with poisonous water with spikes and stuff at the bottom and then cover it with quicksand and cover the area with vegetation so it looks normal. The infantry mens will then fall into the pool and die.

Then for the scare tactics they could use these ideas:

Steal some powerful flashlights/spotlights from the enemy and set up a god statue. Place the spotlights near the god statue and put a curse on the statue. Then place gunpowder near the statue where the enemy will arrive, but not too much that there will be no survivors.

Wait for the enemy to arrive.

First make sure they can see the god statue and read the curse. Then have a man call out on a demonic-sounding trumpet/horn. Activate the spotlights all at once, this will cause the statue to suddenly become 'godly'.

Then quickly set off the gunpowder. Hopefully, most of the enemy will be killed, but a small amount will survive and return to their campsite to tell of the great demonic statue that howled and called down thunder from the skies at them.

The enemy (modern army) will be very confused and will probably believe that the medieval men actually have some sort of supernatural powers.

Chronos 11-07-2016 01:37 PM

Right off the bat, I can tell you that the medieval army is probably not going to be able to hide pits effectively from the modern army, especially not once the modern army knows they're using that tactics. Sure, they look right to human vision, but do they look right in infrared, sonar, and ground-penetrating radar?

And using pits against infantry is right out. Yeah, the first guy might fall in, but then he's going to be pulled right back out by the second guy and the third. And punji sticks aren't nearly as effective when your enemy has antibiotics and first-aid training.

IEDs might work, if (as is likely) the medieval army can manage to steal the materials to make them, but modern armies deal with IEDs so much that there's no way they're going to mistake them for a thunder god. That'd be more likely to work against another medieval army... but there's a reason why you've never read about anyone doing that in the history books.

watchwolf49 11-07-2016 02:57 PM

Put the medieval army in the trebuchet on the plane full of snakes.

snfaulkner 11-07-2016 04:18 PM

Quote:

Originally Posted by watchwolf49 (Post 19759490)
Put the medieval army in the trebuchet on the plane full of snakes.

On an inverted treadmill sideways inside a wind tunnel.

Pushkin 11-07-2016 04:33 PM

Quote:

Originally Posted by DinoR (Post 19745680)
I'm not sure that any knife you'll likely have is harder than the surface hardness inside the barrel. The grooves of the rifling are quite a bit deeper than any small scratch you'd get in quickly anyway.

Leaving it inside might work. Something like jamming the tube into mud fully obstructing the barrel tends to result in the barrel needing replacing if the crew fires before cleaning it out. I'm not sure something as small as a knife would be a big enough obstruction. Feel free to try. Be aware the crew will still have a tank that, other than the main gun, is probably fully functional. That crew will be pissed. Not as pissed as if you shot their cooler and sleeping bags up but still... :D

Is there anything you could pop inside the barrel that would clog it up enough that the thing would jam and cause further damage to the tank?

I'd read in an alt-history book that there was apparently historical precedent from the 1800s for shooting at the ground in front of a cannon in order to throw dirt in the barrel and clog it up.

snfaulkner 11-07-2016 05:57 PM

Quote:

Originally Posted by Pushkin (Post 19759752)
Is there anything you could pop inside the barrel that would clog it up enough that the thing would jam and cause further damage to the tank?

I'd read in an alt-history book that there was apparently historical precedent from the 1800s for shooting at the ground in front of a cannon in order to throw dirt in the barrel and clog it up.

A thermite grenade is perfect for such an endeavor.

Quote:

A classic military use for thermite is disabling artillery pieces, and it has been used for this purpose since World War II; such as at Pointe du Hoc, Normandy.[37] Thermite can permanently disable artillery pieces without the use of explosive charges, and therefore thermite can be used when silence is necessary to an operation. This can be done by inserting one or more armed thermite grenades into the breech and then quickly closing it; this welds the breech shut and makes loading the weapon impossible.[38] Alternatively, a thermite grenade discharged inside the barrel of the gun will foul the barrel, making the weapon very dangerous to fire; thermite can also be used to weld the traversing and elevation mechanism of the weapon, making it impossible to aim properly.

Kedikat 11-15-2016 08:28 PM

I've had thoughts about using super adhesives as weapons. Shoot a shell or missile that splatters on impact and the adhesive seeps into turret ring, maybe gun mechanical bits, hatch crevices ( can't get out ). A non moving tank might be permanently immobilized if hit in the drive wheels and tracks. Some adhesives are very thin liquids that like to seep into crevices and set. They can resist tons of force.
Also, paint bombs. To block optics.


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