SH_MM

CATTB turret

CATTB turret

A rare picture: an overhead shot of the M1 Thumper, used to test the XM291 ATAC gun (sometimes referred to as LW120) in conjunction with the XM91 cassette autoloader.
 

 
The Thumper, which was built out of a M1A1 at Anniston Depot, used a 120mm XM291 in three different barrel lengths, one 265in/6.75m long (the standard, "long tube" XM291), a second one cut the same length as the M256 ("short tube", 5.3m) and a third, intermediary one ("medium tube") that stands somewhere between 6.75m and 5.3m.

On-the-move test fires done at speeds of 10, 15 and 20mph showed that the target impact dispersion (TID) was bigger (read: lower accuracy) with the "long tube" XM291 compared to the "short tube" or EVEN the M256, which was problematic. To support the increased barrel length, Benét Labs also had to create a 415lbs and 22in-long extension for the gun cradle...which was later reused in the proposed installation of a XM360E1 inside the notional M1A3...and, quite likely, inside the M1 AbramsX demonstrator showcased at AUSA 2022.
 
 
 
The 1988 M1 Thumper was only fitted with the 120mm ATAC gun, but the XM291 installed on the 1993 M1 CATTB, on the other hand, went on to trial a 120mm and a 140mm barrel. At one point, the ATAC prototype pool was noted to have successfully fired 1,300 rounds, 150 of which were of the 140mm variety. The latter (at least the KE part) was even judged capable of defeating the armor of what was tentatively described as the FST-3 (Future Soviet Tank 3, essentially a Obj.477/477A); there are no known numbers for the 140mm XM964's performance, but the 140mm ATAC itself was expected to produce a great maximum of 25MJ of muzzle energy. The ammunition for the ATAC was developed by Valentec International and Hercules.
 
 
 
While the Thumper was originally meant to trial the 120mm ATAC, some of the official literature indicates it may have also undergone the 120-to-140mm tube conversion and done static test firings at Aberdeen Proving Grounds, where it showed precision equal to a M1A1 but "with greater penetration".
 

>> Source document for the two above scans <<
 
Also, a common mistake (one I've also been guilty of, mea culpa) I often see around in forums and milblogs is that the Thumper is a derivative of the CATTB, which is false, as the Thumper (AKA the ATAC Demonstration System) predates the CATTB Phase I by at least five years.
 
M1 CATTB Phase I (using a M1 hull as basis), in 93/94, about to be shipped to Aberdeen Proving Grounds for testing:
 

 
Picture of the CATTB Phase II (ATTD?) hull under construction, completed in 1994. Note the closed back with no exhaust grille, the absence of apertures for torsion bars (replaced by a hydro-pneumatic suspension system) and the smaller engine compartment designed to receive a Cummins XAV-1000 AIPS instead of a Honeywell AGT-1500. The freed-up volume between the XAV and the turret basket was reclaimed to accept two vertically-stacked non-ready cassettes housing a total of 22 rounds (either single-piece 120mm or two-piece 140mm), which would have given the CATTB Phase II a maximum loadout of 39 rounds (either 120mm or 140mm), just five less than a M1A2. The huge tradeoff, of course, was that all this made the CATTB massively overweight.
 

 
Apparently, at least one of the two CATTB testbeds is currently sitting at the Sierra Army Depot in Herlong, California, but one has to wonder if it's not a case of mistaken identity; the Thumper was, after all, spotted in 2010/09/30, in Ohio, as it was being relocated by train to parts unknown. Here's to hoping any of these big bois shall make their way to a museum one day, as did the TTB, the Crusader and many others before them.
 
XM291 ATAC with its 17-round Benét Labs XM91 bustle autoloader:
 

CATTB turret

CATTB turret

CATTB turret

CATTB turret

More Dakka
 

 
Not sure how they meant to operate these tail guns 

KMW has showcased that a software update to the Puma's turret and a RF sensor (direction finder) allows it to engage micro-UAVs. I have posted earlier about this in this topic.
 
Below is a marketing photo from Eurosatory 2022, showcasing a Dedrone RF360 sensor on a RCT-30 turret mounted on a Boxer. The sensor would detect radio signals as used to control (micro-)UAVs within a 5 kilometres range and determine the direction from which the UAV is approaching. The software updated to the FCS would then allow (probably automatically) tracking the drone and engaging it.

 
  
 
That is MBDA's Multi-Purpose Combat Vehicle (MPCV) turret, which can be configured for anti-tank use or air-defence use by integrating different missile. It was not proposed by Rheinmetall for the NNbS program, only by MBDA.

KMW has showcased that a software update to the Puma's turret and a RF sensor (direction finder) allows it to engage micro-UAVs. I have posted earlier about this in this topic.
 
Below is a marketing photo from Eurosatory 2022, showcasing a Dedrone RF360 sensor on a RCT-30 turret mounted on a Boxer. The sensor would detect radio signals as used to control (micro-)UAVs within a 5 kilometres range and determine the direction from which the UAV is approaching. The software updated to the FCS would then allow (probably automatically) tracking the drone and engaging it.

 
  
 
That is MBDA's Multi-Purpose Combat Vehicle (MPCV) turret, which can be configured for anti-tank use or air-defence use by integrating different missile. It was not proposed by Rheinmetall for the NNbS program, only by MBDA.

KMW has showcased that a software update to the Puma's turret and a RF sensor (direction finder) allows it to engage micro-UAVs. I have posted earlier about this in this topic.
 
Below is a marketing photo from Eurosatory 2022, showcasing a Dedrone RF360 sensor on a RCT-30 turret mounted on a Boxer. The sensor would detect radio signals as used to control (micro-)UAVs within a 5 kilometres range and determine the direction from which the UAV is approaching. The software updated to the FCS would then allow (probably automatically) tracking the drone and engaging it.

 
  
 
That is MBDA's Multi-Purpose Combat Vehicle (MPCV) turret, which can be configured for anti-tank use or air-defence use by integrating different missile. It was not proposed by Rheinmetall for the NNbS program, only by MBDA.

A few Boxer models proposed by KMW for the German medium forces:
 
Anti-tank variant

 
Anti-drone system (already ordered for the VJTF 2023)

 
Two different mortar options:


 
Fire support

 
"Not-IFV" that is an IFV

A few Boxer models proposed by KMW for the German medium forces:
 
Anti-tank variant

 
Anti-drone system (already ordered for the VJTF 2023)

 
Two different mortar options:


 
Fire support

 
"Not-IFV" that is an IFV

A few Boxer models proposed by KMW for the German medium forces:
 
Anti-tank variant

 
Anti-drone system (already ordered for the VJTF 2023)

 
Two different mortar options:


 
Fire support

 
"Not-IFV" that is an IFV

Leopard 2A6MA3 via Ralph Zwilling (tank-masters.de)
 



 
Fitted with anti-RPG add-on armor developed by KMW at the glacis plate.
 
 

No, this isn't correct. The mass efficiency (ME) doesn't say anything about the plate thickness; keeping the plate thickness constant will lead to an incorrect representation of ME. Mass efficiency just shows the efficiency of an armor material/array compared to a reference armor material/array (typically by definition RHA). So if you have an armor material with a ME of 2, then at a constant mass it will provide twice as much protection as the reference material, i.e. even though you only have 100 kilograms of the material, you would need 200 kilograms of steel armor to reach the same level of protection.
As the density of the materials can be different, the thickness of these two materials needed to reach the same protection level can be quite different. E.g. lets assume that the first material (with a ME of 2) is some kind of low-density reinforced plastic with only a fourth of the density of steel. This would not change the ME, but it would mean that you'd need 200 milimetres of this material to reach the same level of protection as provided by a 100 mm thick steel plate (as 200 mm of the material will have the same weight as 50 mm of steel while having a ME of 2, i.e. being twice as effective per weight). So the thickness is completely irrelevant for the ME.
 
However the above example also shows us the thickness efficiency (TE) of the materials, i.e. the protection provided by an armor material/array for a given thickness compared to a reference material/array (which again by definition is typically RHA). Given that 200 mm of the hypothetical material (something reinforced plastic) provide the same level of protection as 100 mm steel, the TE is 0.5 (half as much protection is provided per thickness).
 
 
I am not sure what these excerpts from Russian and Polish documents say, as I can only use a translator to understand them. But it seems that these are not directly ME and TE, but rather coefficients showing how much mass/thickness compared to steel is needed to provide the same level of protection. It is clearly not TE/ME in case of the Polish document, as this lists polyethylene (i.e. simple plastic) in an array with steel plates with a "thickness cofficient" of 7.1 against APFSDS rounds. As steel + polyethylene does not provide ~7 times the protection for a given thickness (nor does it allow reducing armor thickness significantly compared to pure steel), I would rather assume that this means something along the line of "a polyethylene array with preceeding steel plates need to have 7.1 times the thickness to provide the same protection as a simple steel plate".
 
 
The mass efficiency of simple Al2O3 armor with relatively low purity (95%) is in the area 2-2.5 against small arms when place atop of to an aluminium baseplate. This allows a massive weight reduction compared to steel armor. The efficiency of the armor (and the multi-hit capability) can be further increased by using a higher purity ceramic, a higher strength backplate, an elastic backing in the deformation zone behind the ceramic tile (preferably something like Kevlar/Twaron/Dyneema or UHMWPE) and a cover plate/splinter foil.
 
This means that the ME of Al2O3 can likely exceed 3. For high-performance "nano-ceramics", it can reach up to 5 against small arms. Against APFSDS ammo, the ME will be lower but still decent compared to steel.
 
 
It will significantly improve the protection provided by ceramics, yes. It is also a necessity to ensure that the ceramics don't disintegrate after one hit.

No, this isn't correct. The mass efficiency (ME) doesn't say anything about the plate thickness; keeping the plate thickness constant will lead to an incorrect representation of ME. Mass efficiency just shows the efficiency of an armor material/array compared to a reference armor material/array (typically by definition RHA). So if you have an armor material with a ME of 2, then at a constant mass it will provide twice as much protection as the reference material, i.e. even though you only have 100 kilograms of the material, you would need 200 kilograms of steel armor to reach the same level of protection.
As the density of the materials can be different, the thickness of these two materials needed to reach the same protection level can be quite different. E.g. lets assume that the first material (with a ME of 2) is some kind of low-density reinforced plastic with only a fourth of the density of steel. This would not change the ME, but it would mean that you'd need 200 milimetres of this material to reach the same level of protection as provided by a 100 mm thick steel plate (as 200 mm of the material will have the same weight as 50 mm of steel while having a ME of 2, i.e. being twice as effective per weight). So the thickness is completely irrelevant for the ME.
 
However the above example also shows us the thickness efficiency (TE) of the materials, i.e. the protection provided by an armor material/array for a given thickness compared to a reference material/array (which again by definition is typically RHA). Given that 200 mm of the hypothetical material (something reinforced plastic) provide the same level of protection as 100 mm steel, the TE is 0.5 (half as much protection is provided per thickness).
 
 
I am not sure what these excerpts from Russian and Polish documents say, as I can only use a translator to understand them. But it seems that these are not directly ME and TE, but rather coefficients showing how much mass/thickness compared to steel is needed to provide the same level of protection. It is clearly not TE/ME in case of the Polish document, as this lists polyethylene (i.e. simple plastic) in an array with steel plates with a "thickness cofficient" of 7.1 against APFSDS rounds. As steel + polyethylene does not provide ~7 times the protection for a given thickness (nor does it allow reducing armor thickness significantly compared to pure steel), I would rather assume that this means something along the line of "a polyethylene array with preceeding steel plates need to have 7.1 times the thickness to provide the same protection as a simple steel plate".
 
 
The mass efficiency of simple Al2O3 armor with relatively low purity (95%) is in the area 2-2.5 against small arms when place atop of to an aluminium baseplate. This allows a massive weight reduction compared to steel armor. The efficiency of the armor (and the multi-hit capability) can be further increased by using a higher purity ceramic, a higher strength backplate, an elastic backing in the deformation zone behind the ceramic tile (preferably something like Kevlar/Twaron/Dyneema or UHMWPE) and a cover plate/splinter foil.
 
This means that the ME of Al2O3 can likely exceed 3. For high-performance "nano-ceramics", it can reach up to 5 against small arms. Against APFSDS ammo, the ME will be lower but still decent compared to steel.
 
 
It will significantly improve the protection provided by ceramics, yes. It is also a necessity to ensure that the ceramics don't disintegrate after one hit.

"MEXAS" is a brand name, it does not reference a specific type of armor. Many different armor solutions made out of different materials (ceramics, NERA, only metal alloys, etc.) were marketed as "MEXAS". IBD developed its first add-on armor systems in 1983; I am not sure if the name "MEXAS" was used already back then. The development of the add-on armor for the Leopard 1 started in 1988.
 
"MEXAS" is a brand for products purely developed by IBD, though IBD cooperated with various other companies (mainly as provider of technology/licenses). It was made under license in Canada, the US and Sweden. In Canada, DEW Engineering was responsible for production, in Sweden it was Åkers Krutbruk (later acquired by IBD). In case of the US, MEXAS - or rather armor technology from IBD - was at first tested during the 1990s as part of a government-to-government deal between Germany and the United States (with FMC representing the US side and leading parts of the test program). This apparently was a positive campaign, as MEXAS was selected for the Stryker ICV and a license for production was acquired by Simula. Miscommunications between the US side (primarily General Dynamics) and IBD lead to a replacement of the armor supplier, so that DEW Engineering provided the armor for the later Stryker production.

"MEXAS" is a brand name, it does not reference a specific type of armor. Many different armor solutions made out of different materials (ceramics, NERA, only metal alloys, etc.) were marketed as "MEXAS". IBD developed its first add-on armor systems in 1983; I am not sure if the name "MEXAS" was used already back then. The development of the add-on armor for the Leopard 1 started in 1988.
 
"MEXAS" is a brand for products purely developed by IBD, though IBD cooperated with various other companies (mainly as provider of technology/licenses). It was made under license in Canada, the US and Sweden. In Canada, DEW Engineering was responsible for production, in Sweden it was Åkers Krutbruk (later acquired by IBD). In case of the US, MEXAS - or rather armor technology from IBD - was at first tested during the 1990s as part of a government-to-government deal between Germany and the United States (with FMC representing the US side and leading parts of the test program). This apparently was a positive campaign, as MEXAS was selected for the Stryker ICV and a license for production was acquired by Simula. Miscommunications between the US side (primarily General Dynamics) and IBD lead to a replacement of the armor supplier, so that DEW Engineering provided the armor for the later Stryker production.

"MEXAS" is a brand name, it does not reference a specific type of armor. Many different armor solutions made out of different materials (ceramics, NERA, only metal alloys, etc.) were marketed as "MEXAS". IBD developed its first add-on armor systems in 1983; I am not sure if the name "MEXAS" was used already back then. The development of the add-on armor for the Leopard 1 started in 1988.
 
"MEXAS" is a brand for products purely developed by IBD, though IBD cooperated with various other companies (mainly as provider of technology/licenses). It was made under license in Canada, the US and Sweden. In Canada, DEW Engineering was responsible for production, in Sweden it was Åkers Krutbruk (later acquired by IBD). In case of the US, MEXAS - or rather armor technology from IBD - was at first tested during the 1990s as part of a government-to-government deal between Germany and the United States (with FMC representing the US side and leading parts of the test program). This apparently was a positive campaign, as MEXAS was selected for the Stryker ICV and a license for production was acquired by Simula. Miscommunications between the US side (primarily General Dynamics) and IBD lead to a replacement of the armor supplier, so that DEW Engineering provided the armor for the later Stryker production.

According to a German defence journalists, the autoloader holds only 19 rounds.

Spoke to the Meggitt guy. I’ll reengage today to clarify. 

Kind of sort of a Korean tank but also not really. The Chieftain posted a few pictures this past weekend of an interesting proposal by AAI to the South Koreans for the ROKIT program. As with everything AAI there's nothing online that I could find outside of what The Chieftain posted so I'm not sure of any details beyond what his Facebook post says. I'll keep looking for info but I'm doubtful I'll find anything online.
Facebook post text:
 

 

2S24 for BMP-3 add-on armor kit vs PG-7VS. Result - 2-5 mm deep cavities.

Wow,. thank you @skylancer-3441. Seems like R. Lindström (accidentally?) uploaded some (formerly?) claissified documents in his original presentation. That confirms that the diagram is real, @Militarysta
 
M1A2 turret was also meant to receive add-on armor...


 
Leclerc armor was very poor:

 
Leopard 2 armor evolution:




 
Turret front of a Leopard 2A5 is about 700-800 mm vs KE, 1,600 to 1,800 mm vs HEAT. The Swedish Strv 122 has a different armor package, providing higher protection levels; the Leopard 2 (flat turret) has 300 - 500 mm vs KE protection, but about 50% of the surface is protected against APFSDS ammo with less than 400 mm penetration into steel only.
Note the last slide: The German prototype offered to Sweden (and maybe also the German tanks) have Pakete (integrated armor pacakges) of the technology generation "B", while the Vors. Modul (Vorsatzmodul, add-on module in front of the armor) has the technology generation "D-2". I suppose Sweden uses a more modern integrated armor pacakge (C, D-1, D-2, D-3) and the same Vorsatzmodul. The German wikipedia (without citing a reference) claims that the German Leopard 2 uses "C technology" armor (so "Pakete"). Maybe that's based on Spielberger's book, I need to take a look at it in the future. The graph in the center of the last slide shows five colors... my guess (based on the graphs at the left and the right:
purple - Leopard 2 from 1979, armor package of the "b" generation (fits the graph on the left); red - Leopard 2 with enhance armor package (1987), which might be "C" generation; yellow - Leopard 2 with enhanced armor package (1992), which might be "D-1" generation; blue - Leopard 2 with armor of the "D-2" generation or armor of the "B" generation with Vorsatzmodul of the "D-2" generation green - Leopard 2 with armor as adopted by Sweden - so probably "C" or "D-1/2/3" base armor with Vorsatzmodul of "D-2" generation  
This would lead to the following protection estimates (please note that it says frontal arc - +30° to -30°, not direct from front):
Leopard 2 - 2A4 (from 1979): 300 mm protection vs KE at 60% of the surface, 400 mm protection vs KE at 25% of the surface Leopard 2A4 (from 1987): 300 mm protection vs KE at 65% of the surface, 400 mm protection vs KE at 55% of the surface, 500 mm protection vs KE at 30% of the surface Leopard 2A4 (from 1992): 350 mm protection vs KE at 93% of the surface, 400 mm protection vs KE at 87% of the surface, 525 mm vs KE at 50% of the surface and 620 mm vs KE at 42% of the surface Leopard 2A5 (prototype?): 620 mm protection vs KE at 65% of the surface, 700 mm protection vs KE at 40% of the surface Leopard 2A5 (production model? Swedish model?): 700 mm protection vs KE at 75% of the surface  
That also confirms that the older Leopard 2 models didn't feature the enhanced side armor found on newer production variants:

 
Btw: "gor" seems to be pentrated, "ub" means to be not penetrated in one of the earlier tables.