A10 vs Abrams tank?

[Dog80]

Recently we had a thread about RPGs and the consensus was that they are useless against a modern tank like the Abrams M1.

But how effective is the GAU-8 gun of the A10 against an Abrams?

Also is there a tank with better armor than the M1? If so, then how does it cope against the GAU-8?

[Kilmore]

Well for starters, the A-10 carries more than the gun. And it all depends on where you hit the tank.

[Mekhazzio]

Each round is significantly less powerful than your average RPG-7 shot, so take the same assumptions there and crank them down. Frontal hits negligible, side hits probably a mobility kill due to quantity, rear hits almost certainly a mission kill to engine loss. Crew would only be threatened on top hits, but you're more likely to get that with an RPG from a rooftop than you would from an aircraft. Aircraft tend to not want to fly straight down.

The A-10 carries missiles like the AGM-65 to deal with battle tanks. The cannon is for softer targets.

[Reply]

Each round is significantly less powerful than your average RPG-7 shot, so take the same assumptions there and crank them down. Frontal hits negligible, side hits probably a mobility kill due to quantity, rear hits almost certainly a mission kill to engine loss. Crew would only be threatened on top hits, but you're more likely to get that with an RPG from a rooftop than you would from an aircraft. Aircraft tend to not want to fly straight down.

The A-10 carries missiles like the AGM-65 to deal with battle tanks. The cannon is for softer targets.

So the A-10 typically won't dive at tanks?

[Bear_Nenno]

It dives at about a 30 degree angle. Also, the Warthog is firing over 60 depleted uranium rounds a second! These are some of the most advanced armor-defeating rounds on the planet. Certainly for their size. The Abrams fires a depleted uranium penetrator as well. It is much larger, but the Warthog's gun fires 4,000 rounds a minute. This more than makes up for the smaller size.
The statement that the Avenger rotary cannon is only used on soft targets is insane. It is the primary armament of the Warthog... whose primary purpose is to kill tanks. That cannon is a purpose built tank destroyer and it will cause considerable damage to an M1 Abrams.
Talking about "where it hits" is also misleading. The Warthog is going to aim for, and hit the top of the tank. That's what it does.
It's going to to penetrate the top of the tank multiple times, leaving it in flames and everyone inside dead.

[smiling bandit]

Each round is significantly less powerful than your average RPG-7 shot,

Wait, what do you mean by the word "powerful" here? Are you considering the relative speed assist from the jet's engines?

[Oakminster]

It dives at about a 30 degree angle.

It can dive considerably steeper than that. I have filmed an A-10 firing a AGM-65 Maverick missile in a 70 degree dive.

[Sailboat]

I read recently somewhere an assertion that late-model Abrams have reinforced top armor sufficient that the Avenger is no longer considered likely to pierce the armor at all (obviously damage to external hardware and tracks is still possible if that's true). I have no cite however, as I can't recall where I saw this claim.

[Mekhazzio]

Wait, what do you mean by the word "powerful" here? Are you considering the relative speed assist from the jet's engines?Powerful as in estimated average penetration. Ballpark figures for a round from the GAU-8 at the middle of the engagement range is about 70mm RHA while an RPG-7 round is ~300mm. You're comparing a 3 kg HEAT charge to a 1/3rd of a kg slug. It's a different class of weaponry entirely.
It can dive considerably steeper than that. I have filmed an A-10 firing a AGM-65 Maverick missile in a 70 degree dive.The problem is that in a dive that steep, the time spent within cannon envelope is very brief. Guided weapons that can be lined up from a distance and fired from a much greater range are very different from rolling in, aiming, firing and pulling out in under two seconds. It's one of those things that's technically possible, but very much a hotshot maneuver of questionable wisdom.
Also, the Warthog is firing over 60 depleted uranium rounds a second! These are some of the most advanced armor-defeating rounds on the planet. Certainly for their size.Their size is the entire issue, though: it's a 30mm cannon. It's a very cool 30mm cannon, sure, but it's still just an inert slugthrower. It's a "tank buster" only in terms of the 1960s Soviet tanks it was made for, and there's some debate about if even that wasn't being overly optimistic. It services perfectly well at chewing up everything that's not a main battle tank, which is the large majority of vehicle targets, but it's not magic. The high rate of fire is the only thing that makes it threatening at all to a modern MBT, as it makes track and wheel damage likely from a side shot. Otherwise, it doesn't matter how many times you shoot, if none of them breach the armor.

To put it in perspective, the round the M1 uses on other tanks is (at least) 25 times heavier and fired at half again the velocity, and anecdotal evidence from friendly fire in DS1 suggests that still wasn't enough to penetrate another M1 from many angles.

[Oakminster]

The problem is that in a dive that steep, the time spent within cannon envelope is very brief. Guided weapons that can be lined up from a distance and fired from a much greater range are very different from rolling in, aiming, firing and pulling out in under two seconds. It's one of those things that's technically possible, but very much a hotshot maneuver of questionable wisdom.


Oh, I agree a 70 degree dive is not optimal for a gun pass. Probably wasn't optimal for the missile shot either. I was an aerial photographer in a weapons testing squadron, and we were establishing the limits of performance for the weapon/airplane combination. That particular mission established that the weapon could be safely fired from a Warthog in that flight condition.

Let me add that a 70 degree dive is....sporty. I didn't do many of them. Most dive missions I flew were 30 or 45 degree releases.

[Ají de Gallina]

This thread is porn.

[Grateful-UnDead]

I have a question regarding the overall real world effectiveness of the A-10 in combat situations.

Given the rate of fire for the various guns, as noted above, it seems to me that the A-10 would be good for one burst with each of its guns before it was out and would need to return to base to reload.

If it happened that those bursts missed, then the combat effectiveness of that particular aircraft would be minimal.

Accordingly, to compensate for this, there would need to be a huge fleet of them in the air at any given time in the hope that a few of them would land hits.

Am I right on this? What is the real world experience with this?

[Oakminster]

Am I right on this? What is the real world experience with this?

No. The A-10 is capable of multiple short bursts from the gun. It also can carry a variety of missiles and bombs on the wings. A-10s were used to great effect during Desert Storm...especially against softer vehicle targets. The downside for A-10s is you have to have established control of the airspace before sending them into battle. They are vulnerable to fighters and air defenses.

[thirdname]

It carries enough ammo to fire the gun for about 16.8 seconds.

[Ají de Gallina]

It carries enough ammo to fire the gun for about 16.8 seconds.

16.8 seconds of Hell.

[chacoguy]

I saw one fire a less than one second burst at a gunnery range. It was like God threw a handful of gravel into a pond.

[Bear_Nenno]

Their size is the entire issue, though: it's a 30mm cannon. It's a very cool 30mm cannon, sure, but it's still just an inert slugthrower.But it isn't the entire issue. Not even close. You're completely ignoring the rate of fire. Citing its single round penetration capability is like saying a sniper rifle and a mini-gun will cause the same amount of damage and penetrate the same amount of steel since they fire the same sized round. That isn't true at all.

Ballpark figures for a round from the GAU-8 at the middle of the engagement range is about 70mm RHA And the ballpark figure for 50 rounds placed in a 10ft radius?

that still wasn't enough to penetrate another M1 from many angles.Many angles? You mean the front, the left front, and the right front?

Still say the Abrams is done.

[Mekhazzio]

And the ballpark figure for 50 rounds placed in a 10ft radius?About 70mm :)

The effects of armor degradation from multiple hits isn't something that's been studied exhaustively, to my knowledge, but the general view is that, unless you're attacking reactive armor where relatively large chunks come off each time, you can't expect to land multiple hits close enough to exploit the very tiny weakened area created by a previous hit. When the previous hits aren't even remotely close to penetrating, it's questionable if it makes any vulnerability at all. Your minigun vs sniper rifle analogy is pretty apt. A 7.62 rifle won't get through a bank vault door, and neither will any amount of ammo fed through the minigun - but the minigun might really screw up any external mechanisms that the rifle can't reliably expect to hit.

[Gukumatz]

And the ballpark figure for 50 rounds placed in a 10ft radius?

A 10-foot area of tank with about 20 35mm indentations? (The GAU-8 is accurate to within 80%/20ft radius)


Assuming a full burst at nominal range, I'd expect a full mission kill, mobility kill, tank operators likely unconscious with concussions and ruptured eardrums and who've just shat themselves. A-10 rounds have a tendency - I've read - to cause significant damage to the underside of the tank just from ricochets, so I guess the treads would go no matter which side it shot at. And, realistically, there's a limit to how accurate you can be, moving in an aircraft at a kilometre's distance. Hence the A-10's philosophy of "I want to give everything in that general area one really fucked up day."

What I wouldn't expect is full armor penetration; neither the GAU-8 nor the ammunition it uses is meant to be current-day MBT armour penetrating. It'll still do a hell of a job on whatever it points it's gun at and there's more to tank-killing than armour penetration - but there's a reason it carries missiles as well.

[kombatminipig]

I wish to agree with previous posters that this thread is absolute porn. Please keep the discussion going.

[Kobal2]

Nah, this thread is tasteful erotica. This (http://www.youtube.com/watch?v=mJSk2Xc3Eq4) is pr0n.

[Capitaine Zombie]

It carries enough ammo to fire the gun for about 16.8 seconds.

If that is the case, I really dont understand why the A10 would be so essential to the UN forces in Lybia. Sixteen seconds of fire doesnt sound like the A10 qualifies as a sustaining fire platform at all*. I fail to see the advantages over the classical fighter jets.

*by the way, how long can your average helicopter maintain sustained fire?

[smithsb]

An A-10 can loiter on site much longer without tanker support than an F-15/16/18. The "sixteen seconds of fire" are actually around 11 to 12 separate bursts at different targets. Figure those as kills. The A-10 will carry variable numbers of guided missiles; mavericks and hellfires as examples (maybe two to 16 of the hellfires). A single mission could destroy a dozen or more armored vehicles with precision weapons.

Then we get to the cluster muntions. Each bomb dispensing dozens to hundreds of cluster munitions. These would be multipurpose munitions. High explosive blast, armor piercing shape charges, and incendiary effects. These would be dropped on a column of tanks, light armored vehicles, supply/fuel/troop transport trucks. Pretty much total destruction from the primary and secondary effects. From previous posts; the A-10 is silent in approach (we are talking battlefield noise levels) and very accurate in low level passes.

[kombatminipig]

If that is the case, I really dont understand why the A10 would be so essential to the UN forces in Lybia. Sixteen seconds of fire doesnt sound like the A10 qualifies as a sustaining fire platform at all*. I fail to see the advantages over the classical fighter jets.

*by the way, how long can your average helicopter maintain sustained fire?

Because a fire mission means less than a second of sustained fire. 16 scorched tanks, besides those slaughtered by whatever the A-10 is carrying under its wings, is a lot of bang for your buck.

[LSLGuy]

Jeebus. Waay too many folks watching waay too much Military Channel. The A-10 is cool. It aint' a Death Ray.

I didn't fly it myself, but I know & work with plenty of guys who did or still do. Including in the recent wars.

The gun is used against vehicles & fixed targets. It's typically fired from a very low angle dive, 5 to 10 degrees. Yes, steeper dives can be used with the gun, but that's not the prefered tactic. Much above 20 degrees and you pass through the engagement envelope too quickly to aim effectively. That also means most shots at vehicles are more front / side / back than top.

A typical burst is 1/2 second, giving 30-ish shots per mission. The 4000 rounds per minute figure is with the gun at full rotational speed. Like any mechanical system it has a non-zero spin-up & spin-down time, so 1/2 second is a bunch less than the 66.67 rounds you'd get by just naively dividing 4000/60. And the 1/2 second is measured with the pilot's carefully calibrated trigger finger, so there's some slop there too.

Aiming the gun is relatively easy & the sighting system works well. The gun delivers a concentrated pattern with little dispersion & few flyers. So most rounds from a burst will hit a truck or tank-sized target. If it's a vehicle other than an MBT, it's dead, period. As described somewhere in the over-enthusiastic drivel above, you'll almost always get an M-kill on any MBT, where now it can't move. Getting a full up K-Kill where it's flaming hulk or on its back happens often against older MBTs but less so with the latest & greatest tanks. I don't have any reliable info on the outcome for the crew receiving a less than K-kill hit; But my warthog pals say pretty much everything they shoot quits fighting immediately for one reason or another.

The newest Maverick missiles are the A-10 weapon of choice against late model MBTs. Those can be fired from a greater distance and altitude, which reduces the A-10s exposure to MANPAD & small arms fire. And they're getting close to a one-shot = one kill reliability unless there's heavy smoke. A typical engagement will be from a 10-20 degree dive.


Broadly speaking there are two very distinct types of battles. One is where the enemy has large numbers & it's a melee. You wade in, quickly shoot up all your ammo at the abundant and obvious targets, then go home for more ammo. The famous "highway of death" during gulf war 1 was an example. An A-10 with a full gun and a half-dozen Mavericks might be out of ammo in 20 minutes after taking out 40 targets. My ex-roommate who worked that particular mission a few days & nights said the problem quickly became finding a live target amidst all the wrecked ones. This is also the only scenario where any cluster-type munitions get used.

The other type of battle, and the one most commonly encountered today, is that there are no targets now. But some time in the next 3 hours a couple things will identify themselves as needing killing immediately. For that you want an aircraft which can hang around for 3+ hours and then fairly quickly get to wherever the target is and then despatch it. The A10's long loiter time is more valuable for this mission than the F-16's much greater response radius. And much cheaper for the taxpayer.

Silence: All jet aircraft seem mostly silent on the battlefield. The noise of battle is much more than you can really hear jets over. Any inbound attacking fast jet is moving almost as fast as its noise, so the intended recipient will be surprised unless they see it coming. The A-10 is much slower than its noise but also makes a lot less. Net, net, the two effects seem to cancel out. Helos are both relatively slow and noisy. And they still sneak up on ground troops pretty readily.

[Sailboat]

Silence: All jet aircraft seem mostly silent on the battlefield. The noise of battle is much more than you can really hear jets over. Any inbound attacking fast jet is moving almost as fast as its noise, so the intended recipient will be surprised unless they see it coming. The A-10 is much slower than its noise but also makes a lot less. Net, net, the two effects seem to cancel out. Helos are both relatively slow and noisy. And they still sneak up on ground troops pretty readily.

Also worth noting that one's visual horizon is smaller the closer one is to the ground (not to mention the effects 0of tress, hills, and buildings in obscuring the horizon). Guys in foxholes won't see low-flying aircraft until they're very close. A high-speed, low-flying aircraft is typically able to "ambush" people on the ground, especially if said people have previously been identified and located by other observers.

[Scuba_Ben]

Jeebus. Waay too many folks watching waay too much Military Channel. The A-10 is cool. It aint' a Death Ray.

Nobody's claiming the A-10 is a Death Ray 1920s or any other style. We're claiming it's a Death Projectile Gun.

I would expect that 30mm dep-U rounds would seriously fuck up an MBT's day, acknowledging that the A-10 wasn't designed to kill a modern MBT.

Continuing the comment that this thread is tasteful military hardware pr0n: LSLGuy, your post turns me on. I need to go find my fiancee now.

[Bear_Nenno]

Jeebus. Waay too many folks watching waay too much Military Channel. The A-10 is cool. It aint' a Death Ray.Seems like this comment was directed at me, since I am the only one claiming the 30mm wins. You're wrong though, I haven't been watching the Military Channel. In fact, I haven't watched any American television in 5 years since I've spent 6 of the last 7 years stationed overseas, and 2.5 of those in Iraq and Afghanistan. Nothing I've said has fuck all to do with shit I've seen on tv.
This doesn't make me a subject matter expert, but I am no less qualified to make a guess than your friends.

I do have some unique experience shooting different rounds at different types of personnel armor. One thing I know for sure is that each round weakens the integrity of the armor, regardless of whether or not "huge chunks" fly off.

The whole rest of your post is good info, but it isn't really relevant to the thread. We are talking about theoretical possibilities and hypothetical situations here, not what the A-10 normally does.

[Lust4Life]

It dives at about a 30 degree angle. Also, the Warthog is firing over 60 depleted uranium rounds a second! These are some of the most advanced armor-defeating rounds on the planet. Certainly for their size. The Abrams fires a depleted uranium penetrator as well. It is much larger, but the Warthog's gun fires 4,000 rounds a minute. This more than makes up for the smaller size.
The statement that the Avenger rotary cannon is only used on soft targets is insane. It is the primary armament of the Warthog... whose primary purpose is to kill tanks. That cannon is a purpose built tank destroyer and it will cause considerable damage to an M1 Abrams.
Talking about "where it hits" is also misleading. The Warthog is going to aim for, and hit the top of the tank. That's what it does.
It's going to to penetrate the top of the tank multiple times, leaving it in flames and everyone inside dead.

My experience of seeing an A10 using its Gatler was a very short ZZZZZt.

Watched Jarhead (Which was total crap)and if the film COULD have been spoliled it had a Wart fly past them and fire a Gimpy.

[Chronos]

We are talking about theoretical possibilities and hypothetical situations here, not what the A-10 normally does. Especially since the A-10 and the M-1 are on the same side, and so have never gone up against each other under battlefield conditions, nor are they likely to. Sure, there have probably been some tests done by the military, but those would be under controlled circumstances, and main battle tanks are probably too expensive to justify doing very many of them.

[Lust4Life]

Seems like this comment was directed at me, since I am the only one claiming the 30mm wins. You're wrong though, I haven't been watching the Military Channel. In fact, I haven't watched any American television in 5 years since I've spent 6 of the last 7 years stationed overseas, and 2.5 of those in Iraq and Afghanistan. Nothing I've said has fuck all to do with shit I've seen on tv.
This doesn't make me a subject matter expert, but I am no less qualified to make a guess than your friends.

I do have some unique experience shooting different rounds at different types of personnel armor. One thing I know for sure is that each round weakens the integrity of the armor, regardless of whether or not "huge chunks" fly off.

The whole rest of your post is good info, but it isn't really relevant to the thread. We are talking about theoretical possibilities and hypothetical situations here, not what the A-10 normally does.

Double posting here, I know where you're coming from mate.

Ex Brit soldier,and you get people telling you that inspite of the fact that you've actually done the stuff,lived the life etc. their brothers next door neighbour actually worked with someone who met an SAS soldier once, and he did such and such.

And then they quote Wiki !

Also the Daily Mirror/insert tabloid here, tells you what REALLY goes on, in U.K.Special Forces.

I live with it now.

But I still think that all American Paras are Gay, can't drink and jump at unusually safe heights.

A GRAND !

I could read a book on the way down for fucks sake.

[Bear_Nenno]

Especially since the A-10 and the M-1 are on the same side, and so have never gone up against each other under battlefield conditions, nor are they likely to. Not to mention we're making guesses as to the Classified top armor of the Abrams.

[Lust4Life]

[B]Bear[/B ] in case it wasn't totally apparent was just taking the piss.

Have worked with U.S paras, Lrrps and Special Forces.

Fucking good blokes.


Though obviously not as good as Brits.

[Kobal2]

*by the way, how long can your average helicopter maintain sustained fire?

Apaches carry 1.200 rounds of chain gun ammo, and fire bursts in increments of 5, up to 30 shells in one pinch of the "trigger". Wiki lists the M230 as having a 625 rpm so that'd just under 2 minutes of fire total, but in reality it's more like 60 bursts or more depending on the kind of target the chopper is trying to zap.

Cobras OTOH only pack 750 rounds of 20mm, with a gatling gun that fires faster. Only 1 minute of fire in them, and they won't fuck up tanks quite as well.

Especially since the A-10 and the M-1 are on the same side, and so have never gone up against each other under battlefield conditions, nor are they likely to.

Friendly fire isn't.

[Bear_Nenno]

No, it was obvious. At what height do you guys normally jump, though? For training, anyway.

[LSLGuy]

Seems like this comment was directed at me, since I am the only one claiming the 30mm wins. No Bear, it wasn't directed at you. As a fellow vet I get as annoyed as you do at armchair experts. And yes, I know you've been over there doin' it for real for some time now.

[SenorBeef]

Armor is pretty resilient stuff. Tanks don't have hitpoints - you don't wear them down by hitting them over and over again with weapons that cannot penetrate their armor. I mean, in extreme cases, if you were to hit it over and over again you may stress the armor until it becomes less effective, but a single burst of 20-30 30mm DU rounds isn't going to cause that sort of catastrophic failure on an m1. The delicate stuff on the outside will get wrecked, but the tank itself could probably take the A10's whole ammo load and live.

Think about shooting a hundred BBs at some sheet metal vs one 12 gauge slug.

[Ají de Gallina]

Bear_Nenno and LSLGuy: Can you get your facts out of my porn?

[Bear_Nenno]

For the record, what are you guys assuming the RHA equivalent of the top of the Abrams is? I think that should have been where the conversation started. At issue isn't the unclassified penetration and destruction of the 30mm API, it's the Classified equivalent thickness of the top armor. We've been making statements back and forth without directing the conversation where it needs to be.
So how thick (equivalently thick) do you think the top of the tank is?
I don't think it is greater than 30% of what the front of the turret and/or the front slope are. Which is why I don't think BBs on sheet metal is a good analogy. Especially since I dont think anyone here would claim that the 30mm rounds are just going to bounce off like a BB would. They will at least embed themselves into the armor, transferring all of that energy in the process.

[XT]

Also is there a tank with better armor than the M1? If so, then how does it cope against the GAU-8?

I think the British Challenger series and Germany Leopard II series of tanks also use Chabum armor. As noted by other posters, the thinnest (and least deflective) armor is going to be on top of the tank, so they are as vulnerable to hits from above as the M1 is. I don't think that there is any more advanced armor on a fighting vehicle than Chabum...not that I've heard of anyway, so protection wise they are all pretty close.

-XT

[SenorBeef]

IIRC, the T72B has a top armor equivelant to 300mm of RHA, so I would imagine the Abrahms has at least that, probably significantly better. Wiki lists Gau-8 penetration at 38mm at 1000 yards (seems a bit on the low side to me), I assume for a 90 degree hit but it doesn't say. Coming in at a 10 degree dive actually makes for a poor ballistic angle against the top armor - armor effectively doubles in performance for every 30 degrees you are hitting it off center. If the rounds are hitting the top armor at like 60 degrees off at 1000 yards, you're looking at 38mm worth of penetration on 900mm thick armor (estimating T-72B equivelant at 60 degrees). Not only that, but it's easy to glance at that steep an angle.

Those estimates actually seem somewhat conservative in favor of the A-10 to me.

[SenorBeef]

That's top turret armor, btw. The hull is more vulnerable and engine kills in particular are very possible.

This (http://fofanov.armor.kiev.ua/Tanks/MBT/t-90_armor.html) is where I get 300mm equivelant for T72B turret btw, if I'm understanding that page correctly. I don't quite fully understand everything it says.

[Dissonance]

I suspect that you are misreading it; I don't see a value for the turret top, just turret side and rearSide turret ranges from 40-60cm thick near front thinning to ~ 15-20cm around back. This is probably half and half cast/STEF thus the KE armor is 0.66 while the HEAT armor is 0.77. The effective KE armor ranges from 40cm narrowing quickly to 26cm and 10-13cm around back.The turret is more heavily armored than the hull,The side hull is 6cm thick rolled steel but the lower side hull around the wheels is probably only 2cm thick
...
The rear armor is unlikely to be more than 4cmIt's a safe assumption that top armor is at best equal to the rear armor and almost certainly less.

[SenorBeef]

The light blue value on the top of the turret corresponds to

"44-48cm LOS x 0.66 [Steel/STB] = 29-32cm KE plus K-5 where present = 48±6cm KE
44-48cm LOS x 0.77 [Steel/STB] = 34-37cm HEAT plus K-5 where present = 70±16cm HEAT"

It seems logical to me to interpret the blue as the top of the turret. Red is the mantle, yellow the turret front, and green the turret sides.

[LSLGuy]

I think the British Challenger series and Germany Leopard II series of tanks also use Chabum armor. As noted by other posters, the thinnest (and least deflective) armor is going to be on top of the tank, so they are as vulnerable to hits from above as the M1 is. I don't think that there is any more advanced armor on a fighting vehicle than Chabum...not that I've heard of anyway, so protection wise they are all pretty close.

-XTFor "Chabum" above we should all read "Chobham" as in http://en.wikipedia.org/wiki/Chobham_armor

[XT]

Ah, thanks...wasn't sure how it was spelled and didn't try to Google it since I was posting from my phone. Appreciate it.

ETA: Don't see the Leopard II listed, so might have been wrong about that as well.

-XT

[Mekhazzio]

500mm is out of bounds, that page is referencing the upper curve of the turret side (they're very round). That aside, this actually is one of the few areas where Russian tanks have the advantage, because experiences in Chechnya, particularly the "guy with RPG on top of building" got them sticking reactive armor all over their tanks, including the roof.

The roof armor estimates I've seen for the M1 and Leopard 2 tend fall within the 30-50mm range, aka Very Thin. Even in the 'slathered with reactive armor' best case scenario, you won't get more than 200mm or so. There's just no purpose, from the view of the Cold War scenarios these vehicles were made for, to put armor somewhere that it's not likely to ever be useful, and trying to proof against heavy aircraft missiles would be futile.

The Israeli Merkava is supposed to have the beefiest roof protection of the generation, owing to their greater focus on urban combat, but I've never seen a number put forward. They take anything that might be viewed as a national security secret pretty seriously over there.

[Dissonance]

It seems logical to me to interpret the blue as the top of the turret. Red is the mantle, yellow the turret front, and green the turret sides.If you hover your mouse over the diagram it reads front armor diagram. The light blue isn't the turret roof; it's the top of the frontal turret armor thickness. 300mm RHA equivalent is a foot of armor. The turret has the thickest armor from all angles compared to the hull and it's only 40-60cm near the turret front thinning quickly to 15-20cm at the rear. Compared to this the side hull is 6cm with the rear hull unlikely to be more than 4cm. The roof and the belly of tanks are almost always the thinnest armor; based on these numbers I doubt the turret roof is more than 10cm max and the hull roof 3cm max.

[Capitaine Zombie]

I think the British Challenger series and Germany Leopard II series of tanks also use Chabum armor. As noted by other posters, the thinnest (and least deflective) armor is going to be on top of the tank, so they are as vulnerable to hits from above as the M1 is. I don't think that there is any more advanced armor on a fighting vehicle than Chabum...not that I've heard of anyway, so protection wise they are all pretty close.

-XT

I thought Chobham armor's main weakness was precisely sustained fire (over a greater protection against missiles). No?