M1 Abrams

asianobserve

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Essentially such TV shows are... silly, but sometimes video materials are preatty good, and shows many important details about vehicle design.

It fires up the imagination of fanboys like me...:laugh: But i think it's educational. In part 3 of Anatomy of an Abrams Tank the narrator said that the turret is protected by a combination of glass and ceramic materials.
 

Damian

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It fires up the imagination of fanboys like me...:laugh: But i think it's educational. In part 3 of Anatomy of an Abrams Tank the narrator said that the turret is protected by a combination of glass and ceramic materials.
Narrator do not know what he is talking about. Glass like materials from which some armors were made, for example STEF, or SCA were seen by US as inferior, the Burlington armor and later newer only US made armor installed instead of Burlington BRL-1 and BRL-2 do not use glass like materials and ceramics are not used in especially big quantities if any from what we know currently.

EFP - Explosive Formed Penetrator, AFAIK it not done any extensive damage to tank, and tank back to base on it's own.
 

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This photo is actually great, compare size of soldiers standing near tank and armor physical thickness, sorry for bad quality of drawed lines.

Front turret armor is not fully visible, but gun mantle armored mask, glacis plate (You can see thickness thanks to opened hatch) and lower front hull "beak" armor thicknesses are well visible.



I recommend to compare this with clear photo above in Kunal's post.

Also look what happens with glacis plate thickness if we take in to consideration that it is angled at ~80-82 degrees, look how thickness is increased.

 
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asianobserve

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Promotional video from General Dynamics:

 
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asianobserve

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It's interesting that the Americans have not added bolt-on modular armor to the turret and hull front despite their extensive battle experience in Iraq unlike the Germans with their upgraded Leo 2...
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Damian

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It's interesting that the Americans have not added armor to the turret despite their extensive battle experience in Iraq unlike the Germans with their upgraded Leo 2...
Americans do not add armor on the outside, they invested huge amount of money on basic composite armor upgrades. AFAIK even for FCS program MGV vehicles they were designing ultralight but also very strong as for their weight composite armors. IMHO they used this knowledge and technology for their tanks.

It was in official PDF document about M1 tanks modernisation program, that armor in M1A1SA and M1A2SEP for US Armed Forces was upgraded on front and sides.

In fact both M1A1SA and M1A2SEP with current armor package can use completely different armor than we seenelements of older armor package on some destroyed older variants.

You also should remember that composite armor, at least in western MBT's is semi modular, it means it can be rather easy replaced, I also know that Americans are replacing armor in their tanks, for example when tanks are sended for maintnance, so for example non modernized M1A1HA after such maintnance work can have the same composite armor insterts as much newer M1A1SA. Also armor for M1 tanks is made by goverment institution, so nobody really knows how situation wit it looks like.

PDF:

http://www.fas.org/man/dod-101/sys/land/wsh2011/16.pdf








 

Damian

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BTW, actually the turret addon armor on Leopard 2 tanks is nothing more than NERA/SLERA screens.








Each wedge module for turret front weights ~500kg's. The M1 tanks are using also NERA (Non Energetic Reactive Armor), their basic composite armor have such design, actually all modern western composite armors are very similiar to NERA and can be called semi reactive.
 

asianobserve

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NERA and NxRA operate similarly to explosive reactive armour, but without the explosive liner. Two metal plates sandwich an inert liner, such as rubber.[1] When struck by a shaped charge's metal jet, some of the impact energy is dissipated into the inert liner layer, and the resulting high pressure causes a localized bending or bulging of the plates in the area of the impact. As the plates bulge, the point of jet impact shifts with the plate bulging, increasing the effective thickness of the armour. This is almost the same as the second mechanism that explosive reactive armour uses, but it uses energy from the shaped charge jet rather than from explosives.

Since the inner liner is not explosive itself, the bulging is less energetic than on explosive reactive armour, and thus offers less protection than a similarly-sized ERA. However, NERA and NxRA are lighter and completely safe to handle (and safe for nearby infantry), can theoretically be placed on any part of the vehicle, and can be packaged in multiple spaced-out layers if necessary. A key advantage of this kind of reactive armour is that it cannot be defeated via tandem warhead shaped charges, which employ a small forward warhead to detonate ERA before the main warhead fires.*



*Wikipedia


What's "SLERA?"
 

Damian

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SLERA - Self Limiting Explosive Reactive Armor, it is not widely known term for Explosive Reactive Armor that have limited explosive material, it is generally less energetic than normal ERA and generates smaller explosion. Well at least in a simplified way.

Since the inner liner is not explosive itself, the bulging is less energetic than on explosive reactive armour, and thus offers less protection than a similarly-sized ERA. However, NERA and NxRA are lighter and completely safe to handle (and safe for nearby infantry), can theoretically be placed on any part of the vehicle, and can be packaged in multiple spaced-out layers if necessary.
It is generally true that single NERA/NxRA layer will be less effective than single ERA cassette, this is why NERA/NxRA should be used in several layers. So actually NERA/NxRA in such configuration will be heavier and bulkier than ERA. But effectiveness should be similiar and advantage of NERA/NxRA is as it was quoted that it is safer and also have multi hit capability, something that ERA do not have.

Cadillac Gage In-Arm HydroGas suspension system proposed for M1 Abrams series and other AFV's like M2 Bradley series or even AAVP-7A1 (LVT-7) series.


 
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asianobserve

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Thank you. I don't understand why the Americans did not incorporate this technology in the Abrams when it seems from the picture this has been already available during the Abrams prototype phase?
 

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There were probably many reasons, remember that Congress wanted the best tank for the lowest prize, and designers succed to meet this demand, they get idea to develop weapon systems in so called blocks, each block would have some upgrades.

So initial fielding was succesfull with good tank that is not insane expensive, and upgrades would be just incorporated in future upgrades.

So Block I are M1 and interim model M1IP.
Block II are M1A1 and M1A2 variants.
Block III will be future M1A3.

Currently GDLS is also talking with TACOM and TARDEC to replace torsion bar suspension with HydroGas suspension system among other upgrades.

http://www.ausa.org/publications/armymagazine/archive/2011/9/Documents/SA_0911.pdf
 
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Meggitt Defense Systems
Meggitt Defense Systems - 120mm Compact Automatic Magazine

Link to the Meggitt Company, Compact 120mm ammunition autoloading system for M1 Abrams series, mounted in currently used turret without any extensive modifications, can held 34 rounds ready to immediate use, we can assume that with completely new turret it could hande maybe even 40 rounds.



As we can see, after proper redesign of hull behind turret, it could be possible to increase isolated ammunition storage there from 6 120mm rounds up to ~30 rounds. So this gives interesting opportunities for designers to improve this tank.

However how to achieve this? First step should be new more compact engine, GDLS is allready planning as it is said in one document I posted in this thread, to replace AGT-1500C Gas Turbine with GD883 Compact Turbocharged Diesel.

GD883 should give approx ~950mm of free space in hull.

 
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