About that M60T which survived a Kornet ATGM...

On the 19th April 2016 a photograph of a damaged  M60T tank have been posted on the internet. The tank was attacked by terrorists using supposedly a Russian Kornet (9M133, NATO reporting name AT-14 Spriggan) anti-tank guided missiles (ATGMs). Jane's also reported on this matter.

The M60T tank is a version of the Sabra Mark 2 tank upgrade by the Israeli Military Inudstries (IMI) developed for the Turkish Army. It is based on the Sabra upgrade for the M60 main battle tank (MBT). The Sabra add upgrade includes additional special armor (composite and/or reactive armor), a 120 milimetre smoothbore gun, the Knight fire control system (FCS) and upgrades to the engine aswell as the transmission. 

In case of the Sabra Mark 2 on which the M60T is based, the M60's AVDS-1790 engine and Allison transmission are replaced with the MT881 engine and Renk R304S transmission from the German companies MTU and Renk. The armor solution has been described as hybrid armor, which might suggest a type of ERA in combination with passive armor. However also the combination of non-explosive reactive armor types (NERA, NxRA) with passive armor has been described as hybrid armor.

Damaged M60T tank after the impact of a Kornet ATGM

Following the release of the photograph of the damaged tank, a lot of different claims and opinions on the matter of the effectiveness of tanks, the M60T's armor, ATGMs and the Kornet have been made. While some of these claims and opinions are based on a careful evaluation of the available information and on a reasonable thought process, it appears that a lot of people have abused the incident for preaching their own beliefs — "tanks are dead", "Turkish M60 tank is better armored than Russian T-90", "missiles cannot penetrate ERA/modern armor".

So, what should one learn from the incident? Is the M60T Sabra tank able to survive a Kornet ATGM under all circumstances? Can it survive a Kornet ATGM at least frontally? Or can any old, last generation tank be upgraded with a lightweight armor package to survive an impact from the Kornet ATGM? Is the Kornet weaker than other ATGMs? 

First of all, let's take a few looks at the M60T/Sabra and the Kornet ATGM. The M60T is based on the M60 tank from the 1960s. It uses the original turret and chassis, but has additional hybrid armor laid over the steel construction. How much armor? An approximation for this answer can be found by looking at the vehicle weight: The M60T has supposedly a weight of 59 metric tons - that is between 7 and 8 metric tons heavier than the original M60 model on which it is based. The weight increase is however not only the result of the new armor modules, but is also related to the 120 mm smoohtbore gun, the heavier powerpack and new fire control system components. Just for the reference, the weight of the composite armor modules of the original Leopard 2 turret only (from 1979) supposedly is 8 metric tons, while the turret is considerably smaller! Yes, the original Leopard 2 uses older armor, but instead of just replacing the old armor modules during future upgrades, additional armor was installed, increasing the turret weight by about 5 metric tons.

The Kornet ATGM is meant to combat modern main battle tanks from the front - it's 152 mm calibre tandem warhead is much more capable than the RPG-29 with 105 mm calibre warhead with precursor charge. According to Russian sources the Kornet ATGM can depending on version penetrate between 1,000 and 1,300 mm of steel armor, which given the missile's calibre and the penetration power of modern shaped charge warheads seems plausible.

Above is a screen-capture from the video, which supposedly shows the same M60T being hit by the Kornet ATGM. While it cannot be said for sure that this is the same tank, sources like Jane's have claimed that the only reason for releasing the photograph of the damaged tank was to counter the terrorists' propaganda, which claimed that the M60T was destroyed by the Kornet missile.

The screenshot from the video shows a number of interesting facts. Most importantly here is however the location and the angle of the impact. By comparing the position of the gun (marked in blue) to the path of the missile (marked in red), we can see that the missile approached from the left side (from the tank's perspective) and impacted on the righthand side of the turret frontal armor.

This means that the missile passed the gun barrel and impact on the frontal armor below the gunner's sight at an angle, which made it impossible to hit the base turret behind the armor. The missile's impact path was facing away from the turret. The large module of spaced hybrid armor was probably the only reason why the missile detonated, otherwise it most likely would have missed given the extremely sleek turret cheeks of the M60 tank!

Did the M60T survive a Kornet missile? Yes. Would the missile have hit the tank, if it wasn't for the additional armor module? Most likely not. If the missile had more penetration power, could it have penetrated the M60T's turret and killed the crew? Based on the angle from the video footage, no.

SLEP: Raytheon's new M60 upgrade

Two days ago, Raytheon released a trailer for their new M60 tank Service Life Extension Program (SLEP).

The new features of the M60 after SLEP are an inncreased firing range and accuracy at only one third of the original the costs aswell as an uprated engine, which delivers 950 horsepower instead of the  earlier 750 hp. Electric gun and turret drives replace the previous hydraulic versions, which were slower and a further explosion hazard aside of the ammunition.The old mechanical ballistic computer is replaced by a modern digital fire control system, which also features a digital LCD displays.

Furthermore the 105 mm M68 rifled tank gun is replaced by the 120 mm M256 smoothbore gun of the M1A1 Abrams tank.

The video footage from the prototype shows a number of further changes, which have not been mentioned in the Raytheon video. This might be the result of cooperation with further companies for this prototype. It is fitted with additional slat armor at the front and sides of the turret and very thin passive armor on the hull. An APU and an air-conditioning system have been fitted in large sponson boxes at the rear of the vehicle. 

M60 SLEP tank with slat armor at the turret

Given that these features have not been mentioned, Raytheon's SLEP upgrade might be limited only to their contribution of the upgrade. Photographs of the upgraded prototype have been floating around on the internet since at least 2012. Some Russian sources suggest that Textron might be involved into the development of the prototype. The Turkish company StandartBio included photographs of said tank in one presentation, it seems plausible that StandartBio might have been involved into the upgrade or was at least a partner for pitching this upgrade to Turkey. However this prototype included a number of further changes - it was probably the same prototype from Raytheon's footage, but at a different time of development. At the stage of StandartBio's presentation, the tank was fitted with an additional remote weapon station armed with a LW-25 lightweight chaingun from Aliant Techsystems (ATK). This gun is chambered in the 25 x 59 mm calibre developed for low-recoil and possible use in aircraft. It has been claimed that the tank was also fitted with an even more powerful 1,200 hp engine.

 

Side view of the SLEP prototype: the box at the rear contains the APU

Raytheon's SLEP upgrade for the M60 tank - regardless wether we take the additional features not mentioned by Raytheon into account or not - is not really a good or competitive upgrade. While the market for M60 modernization is very limited, because the tank is strictly operated by poor countries or has been relegated to secondary tasks, other companies have come up with more advanced upgrade solutions. 

The Turkish M60T is based on the Sabra Mk. 2

Israel has already developed three versions of their Sabra tank upgrade, which features thicker and more advanced armor, a comparable fire control systems and a 120 mm smoothbore gun. The Sabra Mk. 1 still uses the old AVDS engine, but uprated to 908 horsepowers - this is quite comparable to SLEP. The Mk. 2 and the Mk. 3 however have replaced the AVDS engine with a MT881 engine from German manufacturer MTU; this offers a 1,000 hp output, better acceleration and lower fuel consumption in a smaller package. A new transmission from German Renk further increases the mobility together with an updated drivetrain.

The Sabra Mk. 2 has been adopted in a special version by the Turkish military as the M60T tank.

The KADDB-designed M60 Phoenix has yet to be adopted in service

The Jordanian KADDB has developed together with RUAG of Switzerland an even more advanced upgrade. The so-called M60 Phoenix also retains the AVDS, but this has been upgrated by General Dynamics to 950 hp output. The Phoenix also has been fitted with a more modern suspension and transmission, a 120 mm RUAG Compact Tank Gun (with increased barrel length compared to the M256) and huge amounts of new composite armor. Ontop of the composite armor, the M60 Phoenix however utilizes SidePro-CE explosive reactive amror, which provides protection against shaped charge warheads (including tandem warhead configurations) and some protection against kinetic energy ammunitions. The LEDS active hardkill protection system has been fitted to the later prototypes, which is able to destroy an incoming RPG or ATGM by firing a small unguided Mongoose missile from one of the two six-round launchers at it.

In general however the M60 tank is not well suited for being upgraded to modern standards. It is extremely tall, resulting in a larger frontal profile and a target easier to spot and to hit. Hence in comparison with a smaller tank, more armor is required to reach a required level of protection. A further disadvantage of the M60 design is it's heavy weight resulting from the relatively thick base armor. While this might sound counter-intuitive in the first moment, the problem is related to the low amount of protection offered by steel armor compared to modern composite armor types: modern composite armor can provide more than twice as much protection against KE and more than 3 times as much protection against HEAT warheads than steel armor of the same weight - this means that instead of having a ten inch (254 milimetres) thick steel turret, a thinner 3-4 inch turret (76 - 102 mm) turret could mount an additional 6-7 inch steel weight equivalent composite armor module without exceeding the weight of the ten inch steel turret.

In case of the M60 and most tanks of the same generation, the situtation is even worse due to utilizing cast steel armor for the turret instead of using rolled steel plates welded together. Cast steel offers up to 20% less protection than rolled steel, depending on the exact composition and treatment. In case of the M60, the cast armor was supposedly very soft at about 220-240 on the Brinell scale. In 1978 the steel composition was altered, probably to provide hardness comparable to the British Chieftain or Soviet T-series tanks (260-280 BHN).
Lastly, the upgrades are quite lackluster in some aspects: more modern tracks are not included, no upgrade provides the commander with an independent (thermal) optic with FCS integration, and the power-to-weight ratio is poor on all models.