Main Battle Tanks and Armour Technology

[methos]

Any details?

Paul-Werner Krapke says that "all new requirements" were fullfilled, but does not specify which or from what point of time on - but it seems that the earliest were not fullfilled. There might be some information about this in another book, which I currently don't have... but I might buy it soon.

which one German "requirements"?

I am not sure, but according to P.-W. K. the Leopard 2AV turret exceeded the U.S. requirements; at a later part in the book he implies that a Leopard 2 could survive a hit by a 125 mm APFSDS from 1,500 m at least. However he does not specify which type of APFSDS.

Typical for US It was impossible to let win german Leopard-2AV...

The Germans were pissed of and rejected buying U.S. AWACS plains following this, the official reason was that the time for spotting enemy jets was reduced by "just" 5 minutes.

Besides this British tested Leopard 2 with armor, their opinion was same as Americans opinion.

My knowledge of the English language might be not the best, but I can't find any reason why "design flaw in the armour integrity" means "is less protected".

Most aspects? In most aspects it was far better than Leopard 2AV. Starting from overall turret and hull design, crew survivability, armor integrity, FCS was not worse, in fact far simpler to use

FCS was less precise.

There were initial problems. There are allways problems when You want to install a longer gun in to tank originally designed with a shorter gun. What the Germans didn't say You that? Band of little liers.

The Leopard 2 was specially prepared to install the L/55 gun and the L/55 gun was specifically designed to fit in the same place were the shorter gun would fit.

 

[Damian]

The Germans were pissed of and rejected buying U.S. AWACS plains following this, the official reason was that the time for spotting enemy jets was reduced by "just" 5 minutes.

Good that they were, after what they were doing with MBT-70... hypocrites will allways be hypocrites.

My knowledge of the English language might be not the best, but I can't find any reason why "design flaw in the armour integrity" means "is less protected".

Because it is less protected when there is flaw in the integrity that can end with higher probability that projectile will go through armor.

FCS was less precise.

Actually the American FCS and stabilization are more precise, I had somewhere data comparision, Americans are slightly better.

The Leopard 2 was specially prepared to install the L/55 gun and the L/55 gun was specifically designed to fit in the same place were the shorter gun would fit.

I doubt that it was designed from start to adapt L55. When Leopard 2 was fielded nobody even thinked about L55. AFAIK Leopard 2 turret needed modifications to mount L55.

 

[methos]

Good that they were, after what they were doing with MBT-70... hypocrites will allways be hypocrites.

And what did they do?

Actually the American FCS and stabilization are more precise, I had somewhere data comparision, Americans are slightly better.

I don't know what data you have (and from which source), but that the Leopard 2AV performed FCS-wise better than the XM1 has been claimed by American (Zaloga, Hunicutt) and German (P-W K, Spielberger, Lobitz) authors.

I doubt that it was designed from start to adapt L55. When Leopard 2 was fielded nobody even thinked about L55. AFAIK Leopard 2 turret needed modifications to mount L55.

That is what I meant with "prepared": The Leopard 2A5 receives (next to redesign the gun mantlet) a number of modifications to the gun mounting, recoil mechanism etc. to be able to receive the L/55 gun.

 

[Damian]

And what did they do?

Started to change requirements, engine (from US made one to German made one), main gun from 152mm gun-launcher to 120mm gun, and so on and so on, that increased costs and delayed the whole program. In fact US should ignore them from the start and design tank on their own, it would end better definetly without all that crap.

I don't know what data you have (and from which source), but that the Leopard 2AV performed FCS-wise better than the XM1 has been claimed by American (Zaloga, Hunicutt) and German (P-W K, Spielberger, Lobitz) authors.

It was only better in having TC PERI, not in stabilization precision.

That is what I meant with "prepared": The Leopard 2A5 receives (next to redesign the gun mantlet) a number of modifications to the gun mounting, recoil mechanism etc. to be able to receive the L/55 gun.

So You see, it was not that easy to just mount there L55. Modification are allways needed.

 

[militarysta]

In fact gun mantled mask in M1 is mucht weaker then in Leo-2... max 360mm vs more then 420mm (propably 480mm if Methos have true).

Most aspects? In most aspects it was far better than Leopard 2AV. Starting from overall turret and hull design, crew survivability, armor integrity, FCS was not worse, in fact far simpler to use.

Sorry but it's not true anymore ;-)
Leopard-2 was better in that aspects:

1) Whit the same mobility it have 3 greate advantages:
a) economy of the engine - les fuel, les fuel in tank.
b) vitality of the engine:
http://img856.imageshack.us/img856/769/ywotnosilnikwczogwobraz.png
c) safety in use - ex lack of 400 engines fire accident in M1.

2)better FCS in Leo-2 (axpecially in 2A4):
a) better WBG-x then TIS (identyfication range >2000m for WBG-x and 1200m for TIS)
b) presence PERI whit limited night sight, in M1 we have nothing simmilar - CWSS is joke when we compare it to PERI so in day it was possible full H-K mode in Leo2A4 when we consier ABC battelfield and crew can't use open hatches and bicoluars.
c) more sensors in the Leopard's FCS and extensive autodiagnostics in RPP 1-8

3) Better Firepower of the 120mm L-44
4) Armour protection - when we consider only turret then Leo-2 is no whorse then M1 becouse - both of them have "bunkers"for ammo whit blow-out plates, but only Leo2A4 have hydraulic pomp separated under blow-out plates. M1 haven't this solution and tank for hydraulic oil and pomps are placed in crew comparmend. In Leo-2 this tank, pomps, and 1 of 2 mechanism is separated from the crew. It's big advantage.
Main armour LOS is obvious bigger in Leo2A1-A4 then in M1 until M1IP:
for 0. 840vs 740mm
for 30. 740 vs 620mm
gun mantled mask: 360mm vs >420mm (480?)
Only one problem in Leo-2A4 is gap for EMES-15.

 

[methos]

Started to change requirements, engine (from US made one to German made one), main gun from 152mm gun-launcher to 120mm gun, and so on and so on, that increased costs and delayed the whole program. In fact US should ignore them from the start and design tank on their own, it would end better definetly without all that crap.

I am sorry, but the Germans never changed the requirements for the guns. It was planned at every time to have a 152 mm gun-launcher armed MBT-70 in the German army. But it was also planned to have a second variant (nicknamed Keiler, the name was later overtook by another concept vehicle) which should be armed with a 120 mm smoothbore gun. In combat the tanks would fight side-by-side, the 152 mm missiles would be used only for long-range fighting (3,000 m was afaik the maximum range for the missile) and when the enemy came closer the more powerfull 120 mm APFSDS ammunition should be used (2,000 m and below). This was also planned for the Leopard 2 at first, with a cannon armed version (Leopard 2K , K for "Kanone") and a gun-launcher armed version (Leopard 2FK, FK for "Flugkörper" meaning missile).
As far as I have read about the MBT-70 it was planned at all times to use a German engine on German tanks and a U.S. engine on U.S. tanks... have you some quote saying otherwise?
Problems existed with the German autoloader, which subsequently was replaced with an American one (the autoloader did work fine with missiles, but it crushed the combustle charges of the normal ammunition).

It was only better in having TC PERI, not in stabilization precision.

I have a problem here. I can understand from a logical point of view that the Leopard 2AV moving a heavier mass should have less stabilization. On the other hand both tanks did use different setups (different stabilization types etc.) and German sources say that the Leopard 2AV had a better stabilized gun, but this was not shown, as the U.S. did only test firing on flat ground.
The stabilization is not the only thing making up the FCS.

The hull ammunition stays the main drawback of the Leopard 2, which might be fixed in the future.

 

[Damian]

Stabilization in M1A1 was better than in Leopard 2A4.

In fact gun mantled mask in M1 is mucht weaker then in Leo-2... max 360mm vs more then 420mm (propably 480mm if Methos have true).

And also much smaller, gun mantle mask in M1 can have higher density due to this with the same weight and protection values.

Sorry but it's not true anymore ;-)
Leopard-2 was better in that aspects:

1) Whit the same mobility it have 3 greate advantages:
a) economy of the engine - les fuel, les fuel in tank.
b) vitality of the engine:

c) safety in use - ex lack of 400 engines fire accident in M1.

2)better FCS in Leo-2 (axpecially in 2A4):
a) better WBG-x then TIS (identyfication range >2000m for WBG-x and 1200m for TIS)
b) presence PERI whit limited night sight, in M1 we have nothing simmilar - CWSS is joke when we compare it to PERI so in day it was possible full H-K mode in Leo2A4 when we consier ABC battelfield and crew can't use open hatches and bicoluars.
c) more sensors in the Leopard's FCS and extensive autodiagnostics in RPP 1-8

3) Better Firepower of the 120mm L-44
4) Armour protection - when we consider only turret then Leo-2 is no whorse then M1 becouse - both of them have "bunkers"for ammo whit blow-out plates, but only Leo2A4 have hydraulic pomp separated under blow-out plates. M1 haven't this solution and tank for hydraulic oil and pomps are placed in crew comparmend. In Leo-2 this tank, pomps, and 1 of 2 mechanism is separated from the crew. It's big advantage.
Main armour LOS is obvious bigger in Leo2A1-A4 then in M1 until M1IP:
for 0. 840vs 740mm
for 30. 740 vs 620mm
gun mantled mask: 360mm vs >420mm (480?)
Only one problem in Leo-2A4 is gap for EMES-15.

1) Better engine fuel efficency is truth.
2) There are no problems with AGT-1500C, in fact it's lifetime before TIGER engine was not worser than most Diesel engines at that time.
3) 400 accidents were not fault of engine but fault of untrained crews, That was mentioned in US Army official magazine ARMOR. And most of these accident was not serious.

4) FCS in Leopard 2 is not better.
5) You again manipulating data of thermal sights if identification range of TIS would be such as You give it here, then Americans in Iraq could not fight at ranges exceeding 2,000m.
6) CWS (Not CWSS or something like such crap) is not PERI, it have different purpose but at day can be used to find target. New SCWS can be considered as alternative to PERI, it have full stabilization and thermal sight + new day sight.
7) You think that there is no diagnostic system in the M1... can we stop this typical German Ubermensche crap?
8) 120mm L44 as a gun have more potential than 105mm L52 but it does not mean that ammunition for 105mm was bad.

US M774 105mm DU 375mm at 2km (1981)
US M833 105mm DU 440mm at 2km (1984)
US M900 105mm DU 520mm at 2km (1991)

US M829A1 120mm DU 610mm at 2km (1991) (Russian estimate 700mm)
US M829 120mm DU 552mm at 2km (1987)

German 120mm DM13 390mm at 2km (1979)
German 120mm DM23 470mm at 2km (1983)
German 120mm DM33/Japanese JM33 550mm at 2km (1987)

As we can see US 105mm APFSDS ammunition was not very worse than German 120mm ammunition of that period.

9) You are once again completely not understand what is the purpose of blow off panels and how they work. Blow off panels work only when pressure is high enough to rip panel from it's mounting. This means that oil won't generate enough pressure to lift the panel. This panel above hydraulic pump in Leopard 2 is only there for service purposes, not some safety messures.

Besides this hydraulic liquids back then were allready difficult to burn, it is idiotic to place difficult to burn hydraulics in to isolated compartment instead of ammunition with semi combustible cases that is far easier to cook off and kill the crew.

10) Armor protection of Leopard 2 is inferior due to placement and size of weak zones. This is the fact, confirmed by both US and UK sources.

But if You wish You can belive in German propaganda, after all they were second in that only to Soviets eh?

 

[Damian]

I am sorry, but the Germans never changed the requirements for the guns. It was planned at every time to have a 152 mm gun-launcher armed MBT-70 in the German army. But it was also planned to have a second variant (nicknamed Keiler, the name was later overtook by another concept vehicle) which should be armed with a 120 mm smoothbore gun. In combat the tanks would fight side-by-side, the 152 mm missiles would be used only for long-range fighting (3,000 m was afaik the maximum range for the missile) and when the enemy came closer the more powerfull 120 mm APFSDS ammunition should be used (2,000 m and below). This was also planned for the Leopard 2 at first, with a cannon armed version (Leopard 2K , K for "Kanone") and a gun-launcher armed version (Leopard 2FK, FK for "Flugkörper" meaning missile).
As far as I have read about the MBT-70 it was planned at all times to use a German engine on German tanks and a U.S. engine on U.S. tanks... have you some quote saying otherwise?
Problems existed with the German autoloader, which subsequently was replaced with an American one (the autoloader did work fine with missiles, but it crushed the combustle charges of the normal ammunition).

No, Keiler is different project that was created after MBT-70 program failed. Germans were changing requirements for MBT-70 making it more and more expensive.

I do not see a reason why APFSDS fired from 120mm gun back then should be more powerfull than APFSDS fired from 152mm gun that was also high pressure one, XM150 was a high pressure gun, not like the short barreled M81 used in M551 Sheridan light tank.

If Germans planned to use their engines on tank then it is another reason to screw them. ACVR-1360 and it's predecessors were no worser than MTU engines. I see no reason why Germans should further delay the project, increase it's costs only to have German made parts in it.

I have a problem here. I can understand from a logical point of view that the Leopard 2AV moving a heavier mass should have less stabilization. On the other hand both tanks did use different setups (different stabilization types etc.) and German sources say that the Leopard 2AV had a better stabilized gun, but this was not shown, as the U.S. did only test firing on flat ground.
The stabilization is not the only thing making up the FCS.

Sorry but I highly doubt in any Germans claims. Both independent to each other sources (US and UK ones) says that Leopard 2 was not in favor in both contests (British Army wanted M1A1 initially untill Prime Minister Tatcher said them to rethink that... everyone knows what that meant).

So I doubt that their stabilization would be better on rough ground especially when it have to move a bigger mass as You said.

 

[methos]

No, Keiler is different project that was created after MBT-70 program failed. Germans were changing requirements for MBT-70 making it more and more expensive.

No. The name was took over by a different (Leopard 1 based programme). But it was planned that the Keiler would be based on MBT-70. This can be read in books and in old news articles.

I don't think that the Germans decided to change the requirements, else could you please show some examples? At least the weight requirement stayed the same the whole time, which was problematic as both the first and the second generation of prototypes exceeded this limit.

I do not see a reason why APFSDS fired from 120mm gun back then should be more powerfull than APFSDS fired from 152mm gun that was also high pressure one, XM150 was a high pressure gun, not like the short barreled M81 used in M551 Sheridan light tank.

The XM150 did still allow less maximum pressure than the Rh 120 L/44 tank gun, was rifled and did have a smaller caliber length.

If Germans planned to use their engines on tank then it is another reason to screw them. ACVR-1360 and it's predecessors were no worser than MTU engines. I see no reason why Germans should further delay the project, increase it's costs only to have German made parts in it.

As far as I have read it was planned to use German engines on German tanks and U.S. engines on U.S. tanks from the beginning of the joint-development.

Sorry but I highly doubt in any Germans claims. Both independent to each other sources (US and UK ones) says that Leopard 2 was not in favor in both contests (British Army wanted M1A1 initially untill Prime Minister Tatcher said them to rethink that... everyone knows what that meant).

So I doubt that their stabilization would be better on rough ground especially when it have to move a bigger mass as You said.

I will try to find exact datas for the German stabilization and FCS.

BTW: What is your source for the ammunition data? Jake C.'s website?

 

[Damian]

No. The name was took over by a different (Leopard 1 based programme). But it was planned that the Keiler would be based on MBT-70. This can be read in books and in old news articles.

I don't think that the Germans decided to change the requirements, else could you please show some examples? At least the weight requirement stayed the same the whole time, which was problematic as both the first and the second generation of prototypes exceeded this limit.

IMHO Germans should stick with original US requirements, this would reduce costs, made one logistics chain etc. etc. etc.

The XM150 did still allow less maximum pressure than the Rh 120 L/44 tank gun, was rifled and did have a smaller caliber length.

Rh-120/L44 was not avaiable back then. I didn't seen any example of that gun mounted on any MBT-70 prototype. German 120mm gun mounted on MBT-70 prototypes was something entirely else, with lenght comparable to XM150.

As far as I have read it was planned to use German engines on German tanks and U.S. engines on U.S. tanks from the beginning of the joint-development.

Because Germans would never agree to use US made engine... so they should think in the first place if they want to participate in JV or not. It's completely idiotic that You joins the JV where goal is one tank with one logistical chain and You say that Your tanks need components made in your country, it is idiotic, especially that US had far greater production capabilities, and US designed components could be also manufactured in Germany, so there would be a huge production base in US, logistic chain would be easier and German workers still would had work... but nooo, Germans as allways "knows better".

I will try to find exact datas for the German stabilization and FCS.

I highly doubt it will be better. I allready posted a table with data, made by a very credible person.

 

[Damian]

Another manupilation. This is armor thickness of original M1, M1IP, M1A1 and M1A2 had thicker armor, but You made all of this like it would be M1IP/M1A1/M1A2 armor thickness.

Militarysta we are buddies but this is pure manipulation! Please take a more care to do this precisely, so people with lesser knowledge on this subject won't be misleaded.

This is the proper armor thickness messures for M1IP/M1A1/M1A2.

 

[militarysta]

@Damian

You are once again completely not understand what is the purpose of blow off panels and how they work. Blow off panels work only when pressure is high enough to rip panel from it's mounting. This means that oil won't generate enough pressure to lift the panel. This panel above hydraulic pump in Leopard 2 is only there for service purposes, not some safety messures.

I suppose that I more then " understand what is the purpose". Hydraulic fluid works under about 6 bar pressure - small? I don't think soo... And this panel above hydraulic pump in Leo2 is normal blow-of plates not service hatch.

Besides this hydraulic liquids back then were allready difficult to burn, it is idiotic to place difficult to burn hydraulics in to isolated compartment instead of ammunition with semi combustible cases that is far easier to cook off and kill the crew.

Just check when and where difficult to burn hydraulic liquids was developed. In 1979 and before 1986 full seperate hydraulic was the best options. You again try to compare tchnology solutions from now to 1980s.reality. Sorry -it does not work.

Armor protection of Leopard 2 is inferior due to placement and size of weak zones. This is the fact, confirmed by both US and UK sources.

I posted smt about this "weak zones" -in fact talikng about "huge mantlet gun mask" is myth becouse gun mantled mask have the same lenght like gun mantled mask + weak area around in M1, T-72, T-80, etc but in Leo2A4 this mask is thicker then in resto of tanks. So this can't be case talking about that. Only problme was place for EMES-15 - but like in Leclerc it was conscious choice to have better main sight optick and night view -and as we can see about WBG-x and TIS - it was better for FCS in 1980s.

You again manipulating data of thermal sights if identification range of TIS would be such as You give it here, then Americans in Iraq could not fight at ranges exceeding 2,000m.

Sorry it can be hard truth for You but TIS really have 1200m identyfication range, when WBG-x have >2000m. It's not my foult. And talking about destroyed target in Iraq in night by M1 whit TIS is simmilar like talking A-10 crews about how many T-72M1 they destroyed. Meybe in TIS they can see small "dot" of smth on that range. But identyfication (not detection!) range is like I post here -1200m and is about 40% worse then in Leopard-2A4.

There are no problems with AGT-1500C, in fact it's lifetime before TIGER engine was not worser than most Diesel engines at that time.

Like in track maybe? 1280km in T-xx in M1 and 10 000km in Dhiel in Leopard-2...
In engine again - 700h for AGT and 3000h for MTU.

400 accidents were not fault of engine but fault of untrained crews,

Yee -sure. Professional crew from US Army made 400 fire accidents but recruiting staff in Bundeshweer hadn't that problem. It's a not about the crew but safety using gas turbine and desel. And in that thema MTU just won.

 

[Damian]

I suppose that I more then " understand what is the purpose". Hydraulic fluid works under about 6 bar pressure - small? I don't think soo... And this panel above hydraulic pump in Leo2 is normal blow-of plates not service hatch.

You are very wrong if You think that fluid leak will open that panel. If there is even any proof it will work? No, neither Germans contrary to Americans ever shown what will happen with their tank in such situation.

But as I said, Germans in case of propaganda techniques are second only to Soviets, if You wish to belive them it's Your problem.

Just check when and where difficult to burn hydraulic liquids was developed. In 1979 and before 1986 full seperate hydraulic was the best options. You again try to compare tchnology solutions from now to 1980s.reality. Sorry -it does not work.

In 1980's Americans allready have non burning hydraulic fluids after Israelis and their own experiences with M60 tanks and problems with their hydraulics.

Maybe sometimes stop reading German made books, and read about others developments.

I posted smt about this "weak zones" -in fact talikng about "huge mantlet gun mask" is myth becouse gun mantled mask have the same lenght like gun mantled mask + weak area around in M1, T-72, T-80, etc but in Leo2A4 this mask is thicker then in resto of tanks. So this can't be case talking about that. Only problme was place for EMES-15 - but like in Leclerc it was conscious choice to have better main sight optick and night view -and as we can see about WBG-x and TIS - it was better for FCS in 1980s.

What?! Do You understand that such placement of sight is simple design flaw? It was from start possible to place these sights like in M1, through turret roof, there is enough place for that in Leopard 2 (in Leclerc might be problematic due to space inside turret). The only things needed to be done that was is to shorten ocular channel, change placement of sight and highten PERI mounting place so it will be above main sight, that all and it was possible then.

Sorry it can be hard truth for You but TIS really have 1200m identyfication range, when WBG-x have >2000m. It's not my foult. And talking about destroyed target in Iraq in night by M1 whit TIS is simmilar like talking A-10 crews about how many T-72M1 they destroyed. Meybe in TIS they can see small "dot" of smth on that range. But identyfication (not detection!) range is like I post here -1200m and is about 40% worse then in Leopard-2A4.

I belive more Americans with their real battle experience than Germans and their fairy tails and fantasions.

Like in track maybe? 1280km in T-xx in M1 and 10 000km in Dhiel in Leopard-2...
In engine again - 700h for AGT and 3000h for MTU.

I have doubts if Germans even provide real data... knowing their preferences to pose like Ubermensche and how they everything make good, the best etc.

Yee -sure. Professional crew from US Army made 400 fire accidents but recruiting staff in Bundeshweer hadn't that problem. It's a not about the crew but safety using gas turbine and desel. And in that thema MTU just won.

Yeah 400 fire accidents when M1 was fielded, 400 only and later none, it was a problem with training during transition from Diesel powered M60 to GT powered M1. If there would be a real problem with AGT-1500C then Americans long time ago would change the engine, and they don't need even MTU designed one. L3 offers 1500HP version of AVDS-1790 (http://www2.l-3com.com/cps/cps/1500_hp.htm), if needed even ACVR-1360 production could start. And L3 is also manufacturing on licence MB883, so they have many options to change engine.

Few years ago there was a photo of M1A2 with Diesel engine on a test track, no deep modifications were needed to install new engine. So they can do this, but it seems that AGT-1500C is not that bad as You tries to show it.

 

[shuvo@y2k10]

can anyone post any information about m1a3?

 

[Damian]

http://www.gdls.com/images/pdf/Modernization/abramsmod.pdf

http://www.ausa.org/news/2012/Documents/ILWBreakfast_LTGLennoxPresentation.pdf

This is the proposal of GDLS and it seems that Army decided to perform this upgrade in increments form. It is still however known as M1 Abrams modernization/upgrade program, and it is unknown if new version will be designated M1A3 or maybe M1A2SEP v3 for example.

It seems that priority in increment 1 upgrade will have armor and several other internal subsystems as it is suggested by AUSA PDF document.

 

[methos]

IMHO Germans should stick with original US requirements, this would reduce costs, made one logistics chain etc. etc. etc.

I don't see your point. The U.S. and the FRG agreed to develop one tank for both countries. Both engines were ready after the conceptual phase, so why should they adopt the U.S. engine? Because they had lost the war? Because the U.S. did want more tanks? This are no reasons affecting the German army. I udnerstood if they would have decided to adopt another enigne because it was better, but this was not true for the ACVR-1100. The MB 873 Ka-500 outperformed it in at least some aspects, unluckily there is not enough data available to say one of these two engines is superior when compared to the other.

Rh-120/L44 was not avaiable back then. I didn't seen any example of that gun mounted on any MBT-70 prototype. German 120mm gun mounted on MBT-70 prototypes was something entirely else, with lenght comparable to XM150.

When it comes to pressure and you have two tubes: one with thick diameter and one with thinner diameter. Put the same amount of propellant at one end and close it after this. If you now ignite the propellant, the barrel with the thinner diameter will have to sustain more pressure. This is why the caliber length (length per caliber) is more important than the total lenght. Jugding from images the MBT-70 prototypes both the 152 mm XM150 gun/launcher and the 120 mm smoothbore gun have the same length, which means that the caliber length of the 120 mm gun will be higher. Furthermore the 120 mm gun is a smoothbore gun, whereas the already larger 152 mm gun/launcher is rifled. This means that the 152 mm gun (which already has a larger internal surface as the 120 mm gun) will have a 20-30% greater surface than a 152 mm smoothbore gun. I.e. the 152 mm rifled gun will have something around twice the internal surface than the 120 mm smoothbore gun, and internal surface is proportional with friction.
For firing sub-caliber ammunition of the same diameter the 152 mm gun would also have a bigger sized sabot -> more parasitic mass.

The 120 mm smoothbore gun fitted to some MBT-70 prototype(s) is not the later Rheinmetall gun, but a predecessor. The barrel seems to be thicker than on the later Rh 120, probably to still achieve a very high pressure while using inferior materials.

US M774 105mm DU 375mm at 2km (1981)
US M833 105mm DU 440mm at 2km (1984)
US M900 105mm DU 520mm at 2km (1991)

US M829A1 120mm DU 610mm at 2km (1991) (Russian estimate 700mm)
US M829 120mm DU 552mm at 2km (1987)

German 120mm DM13 390mm at 2km (1979)
German 120mm DM23 470mm at 2km (1983)
German 120mm DM33/Japanese JM33 550mm at 2km (1987)

As we can see US 105mm APFSDS ammunition was not very worse than German 120mm ammunition of that period.

To come back to this estimates from Jake C.'s site:
According to Zaloga the M833 APFSDS (strongest U.S. 105 mm APFSDS used during the Cold War) penetrates just 420 mm RHA at 2,000 m. The British 120 mm L23 APFSDS penetrates according to him 400 mm at 2,000 m. If we take a look at the dimensions of the L23 APFSDS and the 120 mm DM23 APFSDS we will see that both have a very similar shape (differences in length and diameter should be ~5%) - however the German APFSDS is 125 m/s faster. This means that (depending on vdrop) the German round will penetrate after travelling 1,500 - 2,000 m the same amount of armour as the L23 penetrates point blank. The difference between 120 mm DM23 and M883 should therefore be more than the difference between late 105 mm APDS and early 105 mm APFSDS.
The earliest APFSDS used on the Abrams as the M774 was not available was the M735, penetrating only 300-350 mm at 2,000 m.

But as I said, Germans in case of propaganda techniques are second only to Soviets, if You wish to belive them it's Your problem.
[...]
I belive more Americans with their real battle experience than Germans and their fairy tails and fantasions.
[...]
I have doubts if Germans even provide real data... knowing their preferences to pose like Ubermensche and how they everything make good, the best etc.

Is this really the niveau on which you want to argue?

 

[Damian]

I don't see your point. The U.S. and the FRG agreed to develop one tank for both countries. Both engines were ready after the conceptual phase, so why should they adopt the U.S. engine? Because they had lost the war? Because the U.S. did want more tanks? This are no reasons affecting the German army. I would understand if they would have decided to adopt another enigne because it was better, but this was not true for the ACVR-1100. The MB 873 Ka-500 outperformed it in at least some aspects, unluckily there is not enough data available to say one of these two engines is superior when compared to the other.

Why MB873 Ka500 should outperform AVCR-1100? Not to mention what version of AVCR-1100 You have in mind, and there were 3 version IRCC and the fourth redesignated as AVCR-1360. So I still not understand why German engine should be better... because is German made?

Not to mention that You and Militarysta very easy belive in every German source, but any non German source that claims otherwise is from start qualified by You both as non credible... even if two, yes two independent sources claims otherwise as it was in case of armor protection.

When it comes to pressure and you have two tubes: one with thick diameter and one with thinner diameter. Put the same amount of propellant at one end and close it after this. If you now ignite the propellant, the barrel with the thinner diameter will have to sustain more pressure. This is why the caliber length (length per caliber) is more important than the total lenght. Jugding from images the MBT-70 prototypes both the 152 mm XM150 gun/launcher and the 120 mm smoothbore gun have the same length, which means that the caliber length of the 120 mm gun will be higher. Furthermore the 120 mm gun is a smoothbore gun, whereas the already larger 152 mm gun/launcher is rifled. This means that the 152 mm gun (which already has a larger internal surface as the 120 mm gun) will have a 20-30% greater surface than a 152 mm smoothbore gun. I.e. the 152 mm rifled gun will have something around twice the internal surface than the 120 mm smoothbore gun, and internal surface is proportional with friction.
For firing sub-caliber ammunition of the same diameter the 152 mm gun would also have a bigger sized sabot -> more parasitic mass.

The 120 mm smoothbore gun fitted to some MBT-70 prototype(s) is not the later Rheinmetall gun, but a predecessor. The barrel seems to be thicker than on the later Rh 120, probably to still achieve a very high pressure while using inferior materials.

I agree but still without penetration data of ammunition used by both guns claiming that one was definetly better than another is a bit... biased?

There was indeed problem with XM150 that was probably inherited from M81 with a MGM-51 GLATGM, that needed a so called keyhole in barrel structure, this weakened barrel and shortened it's service life, but that does not mean the gun wasn't good in terms of armor penetration.

To come back to this estimates from Jake C.'s site:
According to Zaloga the M833 APFSDS (strongest U.S. 105 mm APFSDS used during the Cold War) penetrates just 420 mm RHA at 2,000 m. The British 120 mm L23 APFSDS penetrates according to him 400 mm at 2,000 m. If we take a look at the dimensions of the L23 APFSDS and the 120 mm DM23 APFSDS we will see that both have a very similar shape (differences in length and diameter should be ~5%) - however the German APFSDS is 125 m/s faster. This means that (depending on vdrop) the German round will penetrate after travelling 1,500 - 2,000 m the same amount of armour as the L23 penetrates point blank. The difference between 120 mm DM23 and M883 should therefore be more than the difference between late 105 mm APDS and early 105 mm APFSDS.
The earliest APFSDS used on the Abrams as the M774 was not available was the M735, penetrating only 300-350 mm at 2,000 m.

Yes, and either way, penetration values of US 105mm ammunition wasn't bad for that time. Of course I completely agree, 120mm smoothbore had bigger future potential, but at that time it wasn't nececary to field it immidietly.

Ok the other way, think about all this as a system. Single component and data for it might look impressive but what is important is the whole system, long term planning.

Is this really the niveau on which you want to argue?

No, but please, if You can belive them, let me doubt in them. I never praised German designs, in my opinion they are mostly flawed, full of weak spots or wrong design solution. I see in their design lack of long term planning compared to American or Soviet designs.

 

[methos]

Why MB873 Ka500 should outperform AVCR-1100? Not to mention what version of AVCR-1100 You have in mind, and there were 3 version IRCC and the fourth redesignated as AVCR-1360. So I still not understand why German engine should be better... because is German made?

No, but because it has slightly more output and according to the Armor Site (MBT 70 - KpfPz. 70) can be swapped out in 15 mins.

Not to mention that You and Militarysta very easy belive in every German source, but any non German source that claims otherwise is from start qualified by You both as non credible... even if two, yes two independent sources claims otherwise as it was in case of armor protection.

Please tell me were you posted two sources which claim that the German tank is less armoured? The American historians, as already mentioned in another thread, probably base their statement on the gag order from the German government to not disagree with such claims. It has been specifically mentioned in a German book that the armour was not tested. The U.S. tested only weight demonstrators.
I cannot agree with any claim that the frontal armour of the Leopard 2 is less than that of the M1. The Leopard 2 has thicker armour and more weight per armour volume (suggesting more inserts). The EMES-15 location and the gun mantlet are problematic, but in the end they are not less armoured than the glacis of the Leopard 2/XM1.

Regarding the claim in Simon Dunstan's Challenger 2 book: He says that the Leopard 2A4 was rejected "on account on a fundamental design flaw in the armour integrity in the turret front". This does not mean (after taking a look at meaning of integrity) that the armour is less protective. The exact reason behind this statement is unknown to me, but he mentions specifically the turret front, so he is probably refering to the sight/mantlet. At least the problem wasn't existing on the Leopard 2A5 anymore.

I agree but still without penetration data of ammunition used by both guns claiming that one was definetly better than another is a bit... biased?

I don't see much problems. The XM150 can outperfrom an 120 mm smoothbore gun only with much more propellant (or much more effective propellant -> higher pressure). Why should this statement be biased? And if the 152 mm gun/launcher offered the same KE performance as the 120 mm smoothbore gun, then would it be very stupid to operate two versions (one with 120 mm gun, one with 152 mm gun/launcher).
The 100 m gun of the BMP-3 is also pretty long (and it actually is a smoothbore), but in KE performance a much smaller gun can be more effective.

Yes, and either way, penetration values of US 105mm ammunition wasn't bad for that time.

As I mentioned: CIA estimate from "U.S. Intelligence and Soviet Armour".
Kill propability with M735 APFSDS vs T-72: 22%
Kill propability with M774 APFSDS vs T-72: 50-71%

M735 is virtually obsolete at the time the M1 was fielded, while the M774 APFSDS should still work fine against the T-72. The problem is only that improved versions (T-72A in 1979, T-72M1 in 1981, T-80B in 1978) were fielded which were better protected. The M774 became obsolete, the only left round was the M883. with a penetration of 420 mm RHA at 2,000 m (Zaloga) it would already need to get closer than 2,000 m to penetrate the uparmoured T-72A/M1 glacis and penetrating the turret would be only possible at the weaker places or ranges of 1,000 m and below.
Still the ammunition was way superior to what Brittons and French had (Brittons pre-84 only APDS with ~350 mm at 2,000 m, then APFSDS with only ~1,500 - 1,550 m/s mv and French with HEAT rounds and one single(?) type of APFSDS).

 

[methos]

-- deleted --

 

[Damian]

No, but because it has slightly more output and according to the Armor Site (MBT 70 - KpfPz. 70) can be swapped out in 15 mins.

This replacement time depends not only on engine design but also on ARV supporting the whole process. German ARV's have crane that can rotate allmost 360 degrees so vehicle don't need to move around when replacing powerpack. American ARV don't have such crane and need to drive around during the process. From technical point of view, American engines can be replaced as quickly as German ones. AGT-1500C for example needs only to disconnect power cables and fuel cables and 4 to 5 bolts, and that's all.

Please tell me were you posted two sources which claim that the German tank is less armoured? The American historians, as already mentioned in another thread, probably base their statement on the gag order from the German government to not disagree with such claims. It has been specifically mentioned in a German book that the armour was not tested. The U.S. tested only weight demonstrators.
I cannot agree with any claim that the frontal armour of the Leopard 2 is less than that of the M1. The Leopard 2 has thicker armour and more weight per armour volume (suggesting more inserts). The EMES-15 location and the gun mantlet are problematic, but in the end they are not less armoured than the glacis of the Leopard 2/XM1.

Regarding the claim in Simon Dunstan's Challenger 2 book: He says that the Leopard 2A4 was rejected "on account on a fundamental design flaw in the armour integrity in the turret front". This does not mean (after taking a look at meaning of integrity) that the armour is less protective. The exact reason behind this statement is unknown to me, but he mentions specifically the turret front, so he is probably refering to the sight/mantlet. At least the problem wasn't existing on the Leopard 2A5 anymore.

First thing is why we need to belive German sources, not the American ones? What makes German sources more credible? Because they are German ones?

Second is that Brits have obsession on armor protection, if they say that there were problems with armor protection, be it even that weak zone, then this is serious. And You or other Leopard 2 lovers might delude further beliving that weak zone was eliminated in Leopard 2A5 and further variants... it was not and never will be without complete turret redesign.

I don't see much problems. The XM150 can outperfrom an 120 mm smoothbore gun only with much more propellant (or much more effective propellant -> higher pressure). Why should this statement be biased? And if the 152 mm gun/launcher offered the same KE performance as the 120 mm smoothbore gun, then would it be very stupid to operate two versions (one with 120 mm gun, one with 152 mm gun/launcher).
The 100 m gun of the BMP-3 is also pretty long (and it actually is a smoothbore), but in KE performance a much smaller gun can be more effective.

Generally I agree. However still I would not underestimate XM150, we should remember thgat it's main ammunition was HEAT and GLATGM, preatty capable ones with such calliber.

As I mentioned: CIA estimate from "U.S. Intelligence and Soviet Armour".
Kill propability with M735 APFSDS vs T-72: 22%
Kill propability with M774 APFSDS vs T-72: 50-71%

M735 is virtually obsolete at the time the M1 was fielded, while the M774 APFSDS should still work fine against the T-72. The problem is only that improved versions (T-72A in 1979, T-72M1 in 1981, T-80B in 1978) were fielded which were better protected. The M774 became obsolete, the only left round was the M883. with a penetration of 420 mm RHA at 2,000 m (Zaloga) it would already need to get closer than 2,000 m to penetrate the uparmoured T-72A/M1 glacis and penetrating the turret would be only possible at the weaker places or ranges of 1,000 m and below.
Still the ammunition was way superior to what Brittons and French had (Brittons pre-84 only APDS with ~350 mm at 2,000 m, then APFSDS with only ~1,500 - 1,550 m/s mv and French with HEAT rounds and one single(?) type of APFSDS).

And as I said, at that time situation was not that bad, 120mm smoothbore was more capable in the long term but there was not immediate reason to field it.

Especially that at that time Americans tested different guns, 105mm, 110mm and 120mm ones, both rifled and smoothbore. In the end German gun won but it is actually good thing that Americans tested all alternatives avaiable on market at that time.