# M1A1 Panels...Need some info



## Matt308 (Apr 13, 2005)

Take a look at the attached scanned AP photo. The resolution is not too good on my scan, but the pic contains an M1A1 with green panels on the turret fascia that have some writing across the middle. On the left side of the turret appears to be a structure that consists of slats of the same color.

Any insight from the vehicle experts?

Matt


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## DerAdlerIstGelandet (Apr 19, 2005)

If I recall from talking to some tanker guys down in Iraq when I was there. It is a type of reactive armor. It is desigend to break up the incoming round and keep it from penetrating the main armor or the hull of the tank. I may be wrong but this is what I can remember from talking to some of them.


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## Matt308 (Apr 19, 2005)

Kinda what I was thinking. I also don't want to violate any COMSEC or INFOSEC over my own curiosity. I have read about and seen video of reactive armour that is being developed for protection against RPGs. It provides a counter explosion to detonate the RPG a dozen feet or so away from the vehicle. I have also read speculation that the Russians may have imported some new version of RPGs that are more effective against armour. What seems odd would be their use on M1A1s vs Hummers or Strykers. But then again...


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## DerAdlerIstGelandet (Apr 20, 2005)

Nothing there violates COMSEC or anything because it can all be found in newspapers and on the internet. Yes there is a new armor being developed. I dont know about anything of a new version of the RPG but as for the M1A1's I have seen several ones get destroyed so that shows that they are not invincible. The new UP Armored Humvee's that we have are LIFE SAVERS! The Stryker is not the greatest thing like it was made out to be. The armor is not as good as it was said to be. The military is pretty pissed off about it right now.


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## Matt308 (Apr 20, 2005)

Yeah I too having been reading about the Stryker. I get conflicting reports. Fort Lewis is just down the street so you can imagine their Stryker Division gets lots of press. I have read some negative press, but have also seen quite a bit of positive reviews from those who actually ride in them. They claim comfort, security, maintainability and maneuverability are great. I have read reports about the armour, but lets be honest, it is not a tank in any traditional sense. The cage skirts that have been added are apparently adequate, though I do understand that the engines/transmissions are being looked at to maintain original or better power to weight ratio. I have also read that survivability of the Strykers are rather remarkable for such a thin skinned beast. Seems like rather good press from the field on a vehicle that was expedited in design and manufacture.


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## DerAdlerIstGelandet (Apr 21, 2005)

The problem is without the cage skirts, any RPG or even the normal IED's that are killing so many in Iraq right now busts right through the hull.


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## plan_D (May 19, 2005)

It is reactive armour. The M1 is fitted with chobam armour as standard but can be converted with reactive armour in the field, or shop. 

It's to counter missiles or RPGs but there is a type of missile that explodes twice that counters reactive armour. It explodes to explode the reactive armour, then it penertrates the tank and explodes again! Quite ingenius, if I may say so myself.


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## DerAdlerIstGelandet (May 19, 2005)

Very true. I have also seen a round that explodes ones and then fires off a second projectile to penetrate the hull of the tank.


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## trackend (May 19, 2005)

I know that Chobham (you would have thought they could come up with a better name than using the common outside the development center) armour uses a reactive effect and I know that re-active explosive amour is used as add ons but I cant think of the reason for the slats seems a bit self defeating doesn't it.


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## DerAdlerIstGelandet (May 19, 2005)

No the slats keep the round from penetrating the main armour. (Are we talking about the same thing.)


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## trackend (May 19, 2005)

I think so Adler surface mounted re-active counter explodes against the projectile thus keeping it away from the main amour Chobham uses as part I repeat part of its internal structure ceramics that expand at ultrahigh speed when heated by IE amour piercing or HESH rounds and react in oposition to the projectile but most external reactive armour that I know of is placed as slabs rather than slats thats why i found the pic a bit puzzling also it is only covering a very small percentage of the tanks surface area un like for example the Bradley in the pic below


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## Matt308 (May 19, 2005)

Don't know if this helps, but I did see some information on technology used to counter RPGs that actually used explosives to activate RPG warhead about 3-5m from the vehicle. Could the slats located on the sides be perhaps some form of active protection?


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## plan_D (May 19, 2005)

It is some kind of active or reactive armour. I know the M1 can be fitted with the explosive reactive armour, I've just never seen pictures of it. 

Russian tanks show explosive reactive armour much better than Western tanks. Those big blocks of explosives. 

I wonder what they told the first tank crews when they were sticking that on their tank.

Tank crew: "What are you doing to my tank?"
Engineer: "We're sticking explosives on it"
Tank crew: "Oh...right.......GET THE FUCK OFF MY TANK!!!"


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## trackend (May 19, 2005)

Good one D  It does sound a bit barmy dont it I just wouldn't like to be a tank commander with me head out the top if it went off. Im not sure just how much of a clout it takes before it reacts ie small arms or RPG or if you take a corner too tight and bounce off a wall


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## Matt308 (May 20, 2005)

The active explosive armour that I am referring is not "reactive" in the sense that a projective must strike it to activate it. Rather, this "armour" actually explodes prior to contact and thus is intended to initiate explosion of the incoming round about 3-5m from the equipped vehicle. It must use some sort of millimeter wave radar to predict the incoming projectiles trajectory.

It's my understanding that this type of 'active' armour is being reviewed for installation on Humvees and Strikers to counter RPGs.


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## plan_D (May 20, 2005)

That has existed for a while now on Russian vehicles but it doesn't explode a few millimetres away. The RADAR on the tank picks up the incoming projectile and it sends out explosives to blow the missile or round.


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## Matt308 (May 20, 2005)

m=meters

millimeter wave radar is the wavelength of the high frequency energy emissions used to "paint" the incoming round.

This 'active' armour even allowed for friendly personnel to be standing within the 3-5m radius of the target vehicle, the 'active' armour would be intiated, and the friendly personnel would be protected from the resultant explosion. Pretty damn slick actually.


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## plan_D (May 20, 2005)

How does it save personel standing around the tank, exactly? You explode a missile, you can't control the direction of the explosion. 

Anyway, as I said, the technology isn't new. It's obviously been improved though. I have _never_ heard of the M1 carrying that armour though.


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## Matt308 (May 20, 2005)

I actually saw a video of it with dummies set up around a Humvee. The 'active' armour allowed for precision interception of the incoming round and initiated an explosion whose primary forces/shrapnel were directed back parallel, but opposite to the incoming projectile's velocity vector. These forces apparently were enough to virtually cancel all concussive forces and shrapnel from continuing back towards the target vehicle and personnel. Quite amazing. The video did show some concussive forces acting upon the dummies, but TOTALLY out of relation to the HUGE explosion one would expect from the combined 'active armour' and incoming projectile. While the dummies did appear to fall over from some concussive forces, they did not suffer any violent effects that one would normally encounter with such apparent energy. The announcer noted that post review of the dummies indicated on slight injurings would have occurred (minor scrapes and potential hearing damage were noted).

From the video, it appeared very similar to a multiple flare release from a modern aircraft such as a C-130, but obviously on a much smaller scale and time frame. Multiple objects popped off the target vehicle, the rather significant explosions occur and the concussive and shrapnel effects chewed the ground up 3-5m and further away from the vehicle, but within that radius suffered little effect.

Brilliant bit of engineering. But, hey, if it was so brilliant (and cost effective), it would be implemented already.


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## Matt308 (May 20, 2005)

...oh, did not wish to imply that I am aware of this technology being fielded. But the slatted device in the above pic did make me think of this technology only because I couldn't think of what the hell it could be.


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## trackend (May 20, 2005)

Interesting info Matt thanks.
Of course the DU armour on the Abby helps it a bit as well


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## DerAdlerIstGelandet (May 22, 2005)

I have been trying to find some info on those RPG's you are talking about but I have come up with some info on the Abrams armor also.



> The Abrams is protected by a type of composite armor (derived from the British Chobham armour) formed by multiple layers of steel and ceramics. It may also be fitted with reactive armor if needed; however, this modification has never actually been done. Fuel and ammunition are in armored compartments to protect the crew and reduce the risk of cooking off if the tank is damaged. Protection against spalling is provided by a kevlar liner. Beginning in 1988, M1A1 tanks received improved armor packages that incorporated depleted uranium reinforcing rods in their armor at the front of the turret and the front of the hull. Armor thus reinforced offers significantly better resistance towards all types of anti-tank weaponry, but at the expense of adding considerable weight to the tank. The first M1A1 tanks to receive this upgrade were tanks stationed in Germany, since they were the first line of defense against the Soviet Union. US tankers participated in Operation Desert Storm received an emergency program to upgrade their tanks with depleted uranium armor immediately before the onset of the campaign. The newer M1A2 tanks uniformly incorporate depleted uranium armor, and the majority of the M1A1 tanks in active service have been upgraded to this standard as well.
> http://en.wikipedia.org/wiki/M1_Abrams#Armor





> Reactive armor or explosive reactive armour (ERA), is a type of armour used primarily on tanks to lessen the damage from explosions caused from missile warheads, exploding shells, grenades, or dropped bombs.
> 
> Essentially all anti-tank munitions work by piercing the armor and killing the crew inside. Reactive armor's protective mechanism involves producing an explosion or other such reaction when it is impacted by a weapon, actively "pushing back" against it. This is particularly effective against shaped charge warheads, in which the warhead directs a focused jet of molten metal against the armor; reactive armor's reaction disrupts the jet before it reaches the armor's surface.
> 
> ...


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## trackend (May 22, 2005)

Interesting stuff Adler I've just been reading the full account on that British lads VC and his Warrior armoured vehicle was hit with so many of those RPG's that it physically moved the 31 ton carrier but still failed to knock it out one went off 15cm from his head .
I know the Abrams uses second generation Chobham that is made under licence by the US this does add a lot of weight as the DU is 250 times denser than steel also the US favour the HEAT round as opposed to the HESH this is why the Challenger has a 120mm rifled Barrel instead of the 120mm Smooth bore. as always with any development counter measures run parallel be it ERA or Chobham.


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## DerAdlerIstGelandet (May 22, 2005)

What kind of round is it that penetrates the skin melts through and then sends an explosive charge into the hull? I hvae read a little on it but can not remember what it is called or if it is used a lot.


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## plan_D (May 22, 2005)

HEAT rounds. SABOT rounds are high-velocity penertration rounds.


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## trackend (May 22, 2005)

The HEAT doesn't introduce an explosive into the tank though does it D? 
I thought it was a jet of super heated gas and molten Armour the HESH/HEP uses a shock wave to dislodge a scab of metal inside the amoured vehicle and as you say D the SABOT discarded rounds just punches a hole. At least thats what I thought they did.
I found this RPG info
http://www.freerepublic.com/focus/fr/1101708/posts


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## plan_D (May 22, 2005)

The HEAT uses thermal energy to melt it's way in. The Chobam was designed to stop it because the ceramic would spread the thermal energy out giving it no punch from the heat. 

The SABOT uses the mass and speed of the round and puts it all in one small point to punch it's way through.


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## trackend (May 22, 2005)

And I think the air gap is anti HESH/HEP yes?


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## plan_D (May 22, 2005)

I believe so. The only counter-measure to SABOT is reactive armour and just big 'ole fat sloped armour.


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## HealzDevo (May 24, 2005)

I think it might be something to do with waves from the incoming round, hitting the plate and going back out onto the round detonating it. Not 100% sure though. Just what I have gathered about it from reading information.


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## DerAdlerIstGelandet (May 24, 2005)

So what is used more HEAT or SABOT?


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## plan_D (May 24, 2005)

SABOT against armoured vehicles, HEAT against everything else.


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## DerAdlerIstGelandet (May 26, 2005)

Cool thanks.


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## marconi (May 31, 2005)

> High explosive anti-tank, more commonly known as HEAT, rounds are made of an explosive shaped charge that uses the Neumann effect (a development of the Munroe effect) to create a very high velocity jet of metal in a state of superplasticity that can punch through solid armor.
> 
> The jet moves at hypersonic speeds (up to 25 times the speed of sound) in solid material and therefore erodes exclusively in the contact area of jet and armor material. Spacing is critical, as the jet disintegrates and disperses after a relatively short distance, usually well under 2 metres.


The temperature of the jet is only about 500 C.Not so impressive,is it?
The HEAT round doesn't melt through the armor it punches through it.

Actually, reactive armor is designed to defend tanks against HEAT munitions. When it detonates, reactive armor creates a cloud of shrapnel that destroys the structure of the jet.Another way to decrease the effect of the cumulative jet is to construct a defensive screen: 





Cumulative jet loses it's energy quickly, so if you create an obstacle on some distance from the tank's armor it will also decrease the effect of the jet.

Russian active armor is called 'Arena' and here's a picture of it's radar:


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## evangilder (May 31, 2005)

Cool info, marconi. Welcome to the site.


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## DerAdlerIstGelandet (May 31, 2005)

Yeah good stuff. Welcome.


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## Nonskimmer (May 31, 2005)

Interesting. 
Welcome.


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## DerAdlerIstGelandet (May 31, 2005)

What else do you got on the Russian armor there?


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## marconi (May 31, 2005)

Pictures are from www.armor.kiev.ua if you haven't noticed.Although it is in Russuan you can find there some interesting fotos and a few articles in English.

P.S. Sorry for my English I didn't speak or write in it for four years.


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## Nonskimmer (May 31, 2005)

Interesting link. Thanks.
And don't worry about the English. It's as good as mine, and maybe better.


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## evangilder (May 31, 2005)

I am sure your English is better than our Russian! My wife's grandfather came from the Ukraine during the revolution. He lived in Yarmolinitz.


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## Medvedya (May 31, 2005)

Looshye chem moye Rooskoiye illi Ukrainskoye.


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## evangilder (May 31, 2005)

Show off!


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## marconi (May 31, 2005)

Medvedya said:


> Looshye chem moye Rooskoiye illi Ukrainskoye.



Not that bad at all  

If you find something interesting for you on that site you can call me.


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## Medvedya (May 31, 2005)

Dunno about that, that just about reaches the limit of the sort of things I can say. 

Very, very basic stuff - being able to count to ten level.

Vperiod Tovariche! Slava k Krashoi Armyee!

Will not help you much when trying to find directions or buy a beer in Moscow.


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## marconi (May 31, 2005)

Here is an American 'active armor':





SLID(Small, Low-cost Interceptor Device)




SLID projectile
[/img]


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## DerAdlerIstGelandet (Jun 1, 2005)

Nastrovia, that is my extent.


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## Matt308 (Jun 1, 2005)

...aaahhh. Now we are getting somewhere, Marconi. It was this type of technology that I saw and read about. However, it was mounted on a Humvee.

On a similar subject, I have also read a little about the ceramic armour protection. Apparently it too is used as a means of defeating HEAT rounds by slightly deflecting the resultant jet of gases perpendicular to the armour. Claims are that this not only disrupts the gas jet, but also introduces more relative armour to pierce due to the deflection.

Appreciate all those who have contributed. But the slat device on the M1A1 and its purpose remains elusive.


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## DerAdlerIstGelandet (Jun 1, 2005)

The stuff on a Humvee is very rare. We had to fabricate our own armor out of steel plates and jerry rig them to our Humvees.


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## marconi (Jun 1, 2005)

I think those green plates on that tank are depleted uranium plates.I've seen some picture where those plates had writing "uranium plate" or somthing like that.
I've also found an interesting article on that site about electromagnetic anti-cumulative defense.It says that EM field can disperse the jet and decrease its armor piercing effect.And according to the article this kind of armor is now being reserched by Russia and UK.


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## Matt308 (Jun 3, 2005)

The technology that I saw was stated as experimental and not fielded. It also appeard to consist of multiple point defenses targeting a single incoming projectile. Note that Marconi's pic indicates single targeting sensor with a single defensive projectile.


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## trackend (Jun 4, 2005)

DerAdlerIstGelandet said:


> The stuff on a Humvee is very rare. We had to fabricate our own armor out of steel plates and jerry rig them to our Humvees.


That sounds Familiar Adler my old man did the same thing on his LCA in 1944 to cover the slit in the gun pit he was told to remove it by a know nothing RNVR officer. So he had a couple of hooks welded then it could be un-shipped and stowed when the prat was about and replaced during an op.


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## DerAdlerIstGelandet (Jun 9, 2005)

It is a sad thing. You would think the military would better prepare and better equip or atleast equip them for what they are going to do.


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## trackend (Jun 9, 2005)

why dont they ever listen to the guys on the ground and take advice from them on their kit.


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## DerAdlerIstGelandet (Jun 9, 2005)

Because then they would not get richer!


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