Warheads at a turning point.
The military have their share of responsibility in the misuse of certain terms by the media. The word 'surgical', for example, was extensively used during the Gulf War. As soon as a bomb wouldn't go down an air conditioning shaft as planned, but drifted into a nearby street, the media was sure to make their headlines of it. This is because people tend to have a very short memory. After all, what did the allies do to flatten just a ball-bearing factory in Germany during the Second World War? They flattened the whole valley. The author's mentor, who was an RAF Lancaster pilot during the Second World War, once told him that when they were ordered to bomb Cologne one night, he instructed his squadron members to aim for the cathedral's bell towers. He knew what he was doing: this is about all that was left upright after the strike.
This preamble is just to make clear that words have to be carefully weighed when talking about items that have to kill from a distance, because the military and the media do not speak the same language. Another example: 'smart bomb'. Here again, and for the same reasons, the military should have never used this term to designate what is, after all, just a guided bomb.
It had to happen: we are now going the opposite way; indeed, who knows what an 'enhanced blast' warhead is? All right, you are forgiven for not knowing, as the term is indeed pretty new. It is the new euphemism (or politically correct designation) of the thermobaric warhead. But this will not change the fact much. Although they appeared much earlier, the existence of thermobaric weapons was 'discovered' by the mass media after their intense use in Chechnya by the Russian Army, particularly in the form of the vehicle-launched Tos-1 Buratino 220 mm rocket.
What is Thermobaric?
It appears that the word originated in Russia at a time when the Iron Curtain was still up and firm on its foundation. It is thus all the more strange to see that the Russians, and indeed KBP for that matter, consistently refer to the Shmel as a flamethrower. In the West, thermobaric warheads are also referred to as fuel-air explosives, which it is, however, with a huge difference in the time sequence of its operation. In other words, if a thermobaric weapon can be considered a part of the fuel-air explosive family, the contrary is not necessarily true.
Fuel air explosives are designed to operate in two sequences, whereby the shell, or container, is burst open to spread the combusting agent into a fine aerosol (in a volume of air that depends on the size of the shell or container) and then ignite it. This is, for example, the operating principle of the air-launched Commando Vault bomb dropped by the US Air Force in Vietnam--and in Afghanistan under the now famous Daisy Cutter designation. Officially designated BLU-82, this 6.8-tonne weapon contained a mixture of ammonium nitrate, aluminium powder, polystyrene and jet fuel. It is so huge that it has to be parachute dropped from airplanes like the Hercules.
While the purpose of the above weapons is to primarily clear a wide open area--to create a safe helicopter landing spot, for example, the thermobaric explosive warhead, which uses the same basic principle, is aimed at creating an incredibly abrupt overpressure and heat in an enclosed space, followed by a deep vacuum. The overpressure can reach a value of between 2.5 and 3 Mpa while the temperature will soar to a mighty 3000 centigrade and create a blast wave that travels at a speed of 3000 metres per second, burning all available oxygen in the process. This explains the more than suitable choice of the word thermobaric to qualify this type of weapon, as it combines the Greek words of <<thermo>> (heat) and <<baros>> (literally weight, therefore pressure). Interestingly, Russians also describe thermobarics as volumetric explosives, quite rightly one has to admit. A very common error made by the non-specialised press is to describe the performance of thermobaric warheads as a weapon that causes a huge vacuum; the vacuum, of course, comes after the huge overpressure wave and results from the combustion of all the oxygen in the vicinity.
Russia unquestionably has a broad experience with thermobarics, and KBP officially put its RPO-A Shmel (also spelled Schmel) shoulder-launched 93 mm rocket into production in 2001. It is designed for attacks against soft targets like light vehicles and non-hardened buildings; also for bunkers, but only if these can be attacked through their openings. The solution is therefore to also provide penetration.
In the United States, the most recent air-launched thermobaric weapon appears to be the BLU-118/B (if one excludes the possibility the Hellfires mentioned below were of the air-launched variety), which in fact employs the same penetrator case as the BLU-109. The first signs of the existence of this weapon can be traced back to 2001. It can be laser guided to penetrate the entrance of a cave and wreck havoc in such enclosures used as shelters by Al Qaeda in Afghanistan. It was apparently developed in record time after the Twin Towers attack in 2001, and tested in December of that year. But another application would appear, through a variation on the theme, is an attack against chemical and biological facilities: since the extremely high temperatures would allegedly fry any CB agent within the blast area. On a smaller scale, it was revealed by US Secretary of Defense Donald Rumsfeld in early 2003 that thermobaric warhead-equipped Hellfire missiles had been used in Iraq, but no details as to how they were used (air- or ground-launched) were given.
The most recent development in the Unites States--at least amongst those made public--appears to affect the Talley Defense M72 Law. The weapon was recently tested by National Technical Systems, however, very little is known of the actual origins of the thermobaric warhead used in this instance. The purpose of the tests, which were conducted in front of some 30 representatives of the defence industry as well as members of the US Army Special Operations, Navy Seals and US Marine Corps, was to evaluate the suitability of the warhead for <<rapid fielding of an upgraded M72>>. Once more, the word rapid seems to underscore the apparent western need for a technology that it has long neglected.
On an even smaller scale, Ruag in Switzerland has been actively developing new applications for thermobaric warheads. Armada has regularly reported on progress made by Ruag with the Mep penetrator fitted with a conventional high explosive warhead. The Mep, which can be fitted to RPG7, AT4 or Panzer-faust 3 shoulder-fired anti-tank weapons, has proven that it was able to penetrate 20 cm of double-reinforced concrete and, still intact, detonate once it has totally cleared the wall. The enormous advantage of the Mep is that, unlike conventional bunker-buster weapons, which tend to cause just as much damage outside the target as within, the Mep allows for much shorter ranges without any risk to its user and of course reduced collateral damage effects. In fact, apart from a hole, the Mep causes very little damage to the penetration side of the wall. The Mep, strangely enough, will just as easily defeat 1.2 metres of sand bags and blow up within the bunker.
This has led Ruag to combine the Mep with enhanced blast, leading to the Mep Mk 2. Nicknamed Kaybar, it is a scaled-up Mep that could still be launched by light shoulder-fired weapons but, besides the bigger blast afforded by its larger volume, it features what could be termed a smart fuze capable of determining the nature of the target. Indeed, as reported in issue 4/2003 on pages 76 and 78, the Mep's prime advantage is its ability to explode post penetration. No information is available on the type of fuze used, but it is most likely a development from Zaugg--a leader in piezo-electrical energy generating fuzes. It would thus not be too surprising if the firm used this technology to measure the value of the deceleration during the first nano or milliseconds of the encounter with the target; the information could then be used to set the timer. Such a weapon would thus be able to penetrate US Army-standard bunkers and sort out its occupants.
One might argue that a mortar with a thermobaric warhead could do the job. The answer is no, actually, because pin point accuracy would be mandatory--and pinpoint accuracy and mortar are not exactly synonymous. Then, what about using a thermobaric mortar round as an anti personnel round. This again confirms what was said earlier in this article, the open air is the limit of the efficiency of the thermobaric warhead. A properly designed ball-fragmented warhead has a higher efficiency.
Because of the amplifying effect of the scandal press, very few warhead manufacturers will admit that they are, or have been, looking into thermobaric techniques. Yet as mentioned above, the US Air Force and Navy have clearly shown their interest, carried out tests and probably used such weapons in Afghanistan. In this case though, the developers of the chemistry were explosive experts from the Indian Head Division of the Naval Surface Warfare Centre. In fact, all recent types of penetrator warheads would lend themselves perfectly well to a conversion from high explosive to thermobaric. This is, for instance, the case of the Mephisto that equips the Taurus Kepd 350 and the Broach, originally developed by Royal Ordnance onboard the MBDA Storm Shadow, the developments of which, incidentally and not innocently, were initiated in 1991. Since these were developed to penetrate bunkers buried under several metres of sand, they could impressively improve their efficiency.
Improvements on the Classics
Meanwhile, some of the more classic weapons have seen their performance dramatically increase, mainly through refined design. This is the case of Mecar's 105 mm M1060A3 (sabot) and M393E3 (high explosive) rounds. Both have recently been subjects of an article in Armada International, but basically, the performance of the penetrator is mainly due to the fact that it features the highest possible length-to-diameter ratio. During the tests carried out in April 2004, the weapon consistently showed that is was able to cleanly pierce a 250 mm plate of rolled homogeneous steel from an incident angle of 60 degrees and still cause substantial damage to the 10 mm thick rolled steel witness plate placed behind the main target. The 60-degree angle means that the steel rods actually travelled through and cleared 500 mm of armour. On the high explosive front, Mecar very much transposed the know-how acquired with the 90 mm to the 105 mm calibre. The Mecar 90 mm, it must be emphasised, is undisputedly the leading round for the Cockerill gun. During the same tests in April, the HEP-T showed that three rounds could punch a 95-cm-wide and 185-cm-high passage in an eight-inch thick double reinforced concrete wall, neatly cutting all steel bars in the way. The requirement having been 75 x 125 cm, the round was promptly adopted by the US Army for its mobile gun system.
Another classic is the mortar round. In this instance Ruag has once more made a great achievement (but more about this later)--here in the form of the 60 mm Mapam. The objective of the Mapam is to create the highest possible lethality in a perfectly controlled area. To fulfil the aim, Ruag uses a mortar bomb skin that is composed of over 2400 perfectly calibrated steel balls embedded within a composite bond. Both the calibration and their arrangement ensure that all balls would travel at virtually the same speed, over the same range with the same penetrating power. And tests demonstrated that the theory perfectly turned into reality. Furthermore, the Mapam is filled with insensitive PBXN-110 explosive and has also been submitted to Stanag-standard cook-off tests, with positive results, With the 60 mm Mapam, Ruag claims that it can achieve the same performance as a standard 80 mm round. This alone prompts the question, <<and what would an 80 mm Mapam do?>> Well, Ruag is actually working on this, so the answer will probably be published in a few months.
In the meantime, Ruag has also developed the Pearl hand grenade that very closely follows the path of the Mapam (see full details in Armada 3/2004 page 28) with the only difference that it can be had in diameters of 49, 55, and 65 mm with a choice of six steel ball diameters, which offers a wide range of performances. Stricto sensu, hand grenades are not within the scope of this article, but it is interesting that the same advanced concept can be applied to smaller weapons and for the same reasons: perfect control of the weapon's performance.
On the hollow charge front, a very recent improvement came not from the warhead, per se, but from the addition of an improved sensor. This is the Franco-Swedish Bonus top-attack warhead in which the existing laser has been replaced with a ladar--courtesy of miniaturisation--leading to the Bonus Mk 2. The ladar allows the warhead to gain a better profile of the target, which was rendered necessary by existing or future cooling devices as well as the proliferation of fooling devices such as flares. The sensor will thus better identify the size of the detected target and discriminate invalid thermal sources and cut down double kills. So far Sweden and France have ordered 3000 and 6000 shells respectively (one shell carries two rounds), but the last 1500 to be delivered will carry Mk 2 warheads.
The author is perfectly aware of the fact that this article on recent warhead breakthroughs might be slightly Ruag heavy, which is a bit embarrassing due to the fact that the firm is virtually a neighbour. But the facts speak for themselves. What is more, Ruag is a former bureaucracy-driven, state-owned military arsenal. Today converted to modern business rules, and no longer able to rely on Swiss Armed Forces orders, Ruag has had to shift its design offices into overdrive and produce the best to survive. Few know, for instance, that the improved Tow missiles use the Swiss-made WH 96 warhead and that the only reasonably effective Dragon anti-armour guided missiles is the type upgraded with the WH 2000 tandem charge. Ruag also has developed co-operative ties with Vazovsky Mashinostroitelni Zavodi in Bulgaria to bring warhead improvements to the Malyutka, the Konkurs (know as the Faktoria Top 100 out there) and of course the VPG-7 (in other words the RPG-7) fitted with the Mep penetrator.
Probably even less known is the origin of the Bill 2 and MBT Law warheads. Unbelievably it is Ruag again. But there is a reason for this. Ruag has developed what it calls <<shrink fit>> warhead machining. Broadly speaking, the idea consists in cryogenically shrinking an explosive blank, which can then be safely machined to tight tolerances and then fitted into the warhead case. It can thus expand upon warming and therefore snugly fit the walls of the casing; thereby almost certainly avoiding the presence of cracks and bubbles. Such a precision is totally mandatory for downwards-firing, horizontally-travelling warheads, as is the case of the Swedish weapons mentioned above. The reason is that those warheads must be of an asymmetrical design so the downward punch generated will remain straight in line with the original impact point on the attacked armour, otherwise a phenomenon know as the 'keyhole effect' will ensue. In simpler terms, the jet will behave like a cutting torch but one that will merely etch a groove on the thick armour.
More to come, Undoubtedly
As we can see, a lot of refinement has gone into warheads, not only in recent years, but also in recent months. And there is more to come, some manufacturers having told the editor that they were cooking up new things but <<hush, it's still too early!>> Watch this space.
A systematic typing error has crept into the article "Mecar's Breakthrough, Literally ..." in the last issue (3/2004, page 144) of Armada International. The error was a reference to the thickness of the targets that should have read 250 mm and 500 mm instead of 25 mm and 50 mm respectively.
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|Title Annotation:||Warhead Technology|
|Author:||Biass, Eric H.|
|Date:||Aug 1, 2004|
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