Somehow I always end up ressurecting older threads (even though probably noone will reply to me). Well, I just read this thread and have seen quite a few reasons why the urge to answer (and correct some statments) in me rises.
I hope this is not seen as problem by the moderators/administrators of this forum.
First of all to come back to the beginning of this thread:
Every tank is destructible. The good performance of the M1 during Gulf War is based on a variety of reason, but the main reason should be the fact that the largest part of tanks used were M1A1HA or M1A1HC with reinforced armour just developed a few years prior the war.
The first version of the M1 Abrams was designed to survive hits from 115 mm APFSDS fro 800 m as KE threat and 127 mm shaped charges as CE threat (see Hunnicutts book about the Abrams). It appears that the Soviet Union did not use tungsten-cored or DU APFSDS for their 115 mm gun at this time.
Zaloga therefore assumes that the M1 protection was equivalent to 350 mm RHA vs KE and 700 mm - enough to survive 115 mm steel cored APFSDS and ITOW missiles. Contemporary Soviet APFSDS would have pierced through the armour from 1,500 - 2,000 m at least.
The U.S. were aware that there requirements were too low to protect from contemporary Soviet anti-tank ammunition (they also knew that the 105 mm gun was too small to effectively deal with a T-72) and thickened the front turret armour on subsequent models (IPM1, M1A1) by ~220 mm (it might be that they changed the composition of the armour at this time).
Four years later the armour was again changed, this time without thickening, but DU was incorporated.
The Iraqi army did only have ammunition which was used by the Soviets
before the first M1 tank was built. This ammunition was only made of steel and would have probably been capable of dealing with the basic M1 model from 1,200 - 1,500 m range, but nearly all Abrams tanks used in Gulf War were M1A1 models (of which the majority was HA or HC configuration). According to the Osprey face-off title "M1 Abrams vs T-72 Ural" only 2 of 36 M1 squadrons/battalions were basic M1s, and these were not alligned to armored/calavry units, but to the 1st Infantry Division. Iraqis were no threat to the M1A1s/M1A1HAs.
I doubt that the story with the 4 x M829A1 versus a knocked-out M1A1(HA). I have read this story somewhere else too, but it just doesn't make any sense, it is probably a myth. Why? Because there are many place where even older APFSDS can penetrate the armour of the M1A1(HA). The mantlet armour is less than half as thick as the turret front armour, so is the side armour. The hull front armour is 1/3 - 1/4 thinner than the turret front armour... the soldiers shooting with APFSDS at the turret front to disable it would be pretty dumb - the soldiers I have met are not.
The armour thickness is not the same at every place, hull side armour can be perforated by medium caliber cannons, so can the rear armour. No tank is indestructible.
Here is a drawing about the side armour of the M1A1HA, based on images of a damaged vehicle. The outermost layer of the armour is RHA, followed by a shock-mounted spaced armour combination. After this many sloped layers of what appears to be NERA follow, and further inside is a laminate of three layers - if there are DU layers or ceramics in the side armour, they have to be located here.
Short correction of some statements (sorry could not resist):
The German Leopard 2 might use "Chobham armour". Official UK documents show that Burlington armour (the official designation, Chobham is an inofficial name) was presented to the Germans already in 1970.
The Germans did have some cooperation with the UK, including the development of a common MBT during the time the Leopard 2 was believed. I think that some author also mentioned directly that "Chobham armour" was given to the Germans.
However the Germans decided not to field the basic Chobham armour, but instead developed an own version following the same design/working mechanism. There are claims that this has been done because Chobham did have a unsatisfactory performance when it comes to KE protection. According to the declassified UK files Burlington (at least the 1970s version) was per weight not worse in KE protection than normal steel - this does not exclude the possibility that it might have a higher mass-efficiency than 1, but it seems to be improbable. Since the contemporary 125 mm APFSDS did have a penetration of 500+ mm RHAe on short ranges, the armour would need to weigh as much as 500+ mm steel than.
The British L30 gun and the CHARM 3 APFSDS are, contrary to what has been said here, inferior to the smoothbore gun and ammunition. The CHARM 3 APFSDS is the fastest UK APFSDS developed ever, but has a muzzle velocity of only 1,650 m/s and a length of below 70 cm. The US M829A2 APFSDS has a muzzle velocity of 1,680 m/s and a length of 78 cm, while the German 120 mm DM53 APFSDS has a length of 75 cm and a muzzle velocity of 1,750 m/s.
While the barrel of the L30 tank gun is longer than the basic Rh 120 and the M256, it is rifled - this results in a 20 - 30% greater surface -> 20 - 30% more friction. Furthermore the L30 tank gun cannot support as much pressure as the Rh 120, which means that the higher friction cannot be nullified by the use of more propellant.
I wonder if anyone has a source regarding the claims that the Panzer 87WE was offered to Australia... that does not make any sense. I am sorry for this,
[Admin. Deleted] , but I have to question the validity of your claims unless you can provide a source for them. Various internet discussions on websites like this have shown me that distrusting any claims which cannot be verfied after hour long google-ing or taking a look into literature is the best idea, because personal likings and patriotism is always a factor in discussions. When the Australians ordered their tanks, the Panzer 87 WE was still in development phase.
You also claim that the M1A1 AIM was found to be better protected... how comes when the Pz 87WE has thicker and more modern armour?
And a last thing I would like to comment on: the M1 vs Leopard 2 part. I know that "versus"-threads/posts are not allowed here, but this has already been started and I think that I and all other people who have posted and are willing to contribute here will doing this factually. Else feel free to delete this part, but then you actually should also delete a few posts by
[Admin. Deleted] .
We don't know if the M1A1 has thicker armour than the Leopard 2. The basic M1 is estimated to have between 600 mm estimates done by pro-Russians) and 740 mm (estimates done by pro-US people) turret armour thickness. How thick the armour is exactly is unkown to us, most estimates are affected by patriotism. Wikipedia assumes a thickness of ~650 mm, but there is no source given - maybe this was added by a soldier who did inofficially meassure the armour or the value was added by some fanboy... However I think ~65 cm is more reasonable than ~75 cm, because the Russians did manage to achieve nearly immunity against 105 mm APFSDS (which are made of heavy metal alloys) from as close as 500 m with 60 cm armour. The armour however was less sophisticated and weighs probably more than Burlington would weigh.
If we add the ~220 mm reported in literature, then the values will increase to 820 - 960 mm (wiki reports 880 mm). The actually known armour thickness of the Leopard 2 (up to 2A5) is 840 mm (measured by differently people independently) - so in worst case the M1A1 has slightly less armour, in best case significantly more. However that would mean that the US would need ~120 mm more armour, for reaching the same level of protection (near immunity against 125 mm rounds) at least under the assumption that the armour offers the same protection per space.
The claim that a "single package" of armour will offer more protection is something
[Admin. Deleted] made up in his mind (and people inventing "facts" are a reason why internet discussions always end up with no result) - in fact spaced armour is
per weight (not per thickness) always more efficient as a single armour package. The Leopard 2A5 wedges consist of multiple NERA-layers (this is the reason why the applique armour is sloped) and according to literature they are made of HHS (high-hardness steel). Research files (e.g. Int. Symposium of Ballistics) have shown that a single 36 mm line-of-sight NERA layer made of 440 HB steel and rubber is already capable of significantly damaging the penetrator in similar ways as heavy ERA. The empty space is there to allow the fragments of the penetrator to spread (so that the energy is not focused on a single point). The "armour box" in the frontal wedge contains two layers each with a LOS-thickness of ~7 cm and the empty space is partial occupied by other NERA layers (but these cover only a small aspect of the frontal profile). The Leopard 2A5 turret weighs as much as the M1A2 turret, while the M1A2 has a larger frontal profile under armour and does have twice as much composite armour at the sides... the Leopard 2A5 is better protected.
There is also no reason to assume that the most dense material in the Leopard 2 armour is steel - we don't know the composition, some people believe that there is tungsten inside (wikipedia among others). However dense materials does not mean superior protection. HHS is stronger against KE than DU per thickness and per weight (at least than pure DU and an alloy which was reported in the Int. Journal of Impact Engineering). Weightwise ceramics and NERA (however not thicknesswise) are more efficient than DU vs shaped charges (where the penetration process is dependent on density).
On the early models there is still plenty of armour behind the EMES-15 (gunner's sight) - about 65 cm. This is less than the rest of the turret, but it might be more space-efficient armour (which then would be less weight-efficient). Depending on estimate this is as much armour as the M1 has on the front and is always as much (or even slightly more) than the Leopard 2 (without hull applique) and the M1 have at the glacis. Surely a weak spot, but the glacis of every tank is also a weak spot. On the Leopard 2 the size of the mantlet was reduced and the sight was moved, resulting in the closure of all potential "ballistic gaps", while the mantlet of the M1 is the same as always.
The radio is positioned in such a way that the commander can operate it - it is his task. It might be that the U.S. prefers to let the loader operate the radio, but that's depending on doctrine. In early M1 and M1A1 the commander did have not a periscope, while the M1A2 does not feature a daysight-channel for it.
Regarding the hull ammo - did you notice that this is located in a very safe place (i.e. from +/- 30° always as much armour as the glacis has has to be penetrated) and that every country except the U.S. does store some ammo unisolated in the hull? A tank is made by adopting many different compromises in the design (which depend on the needs of the builder). The U.S. carry nearly twice as much composite armour at the turret sides (without getting better crew protection, as the turret bustle is not connected with the crew comparment), which is a drawback other countries did not want to accept. In the end the Leopard 2 did win every comparision with the M1 (including the US evaluation) except the Australian.
