p. dearden- new blast weapons

8/3/2019 P. Dearden- New Blast Weapons

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J R Army Med Corps 2001; 147: 80-86

ABSTRACTOver the last decade a large number of

weapon systems have appeared that use blast as their primary damage

mechanism. This is a notable trend;until recently very few warheads reliedon blast as their primary output. Most

warheads in service use explosives todrive metal such as fragments and

shaped charge jets to engage targets.New technologies are now being

integrated into warheads that claim tohave enhanced blast performance. Blastweapons could have been designed to fill

a gap in capability; they are generallyused for the attack of ‘soft’ targets

including personnel, both in the openand within protective structures.

With the increased number and range

of these weapons, it is likely that UK forces will have to face them in future

conflicts. This paper briefly describesfuel-air explosive blast weapons andreviews a range of enhanced blast

weapons that have been developedrecently. The paper concludes with a

brief discussion on the reasons whyenhanced blast technologies may beproliferating and how this could affect

the Defence Medical Services.

IntroductionChemical energy and kinetic energy are usedto attack military targets. Energetic materialssuch as propellants may be used to accelerateinert projectiles for the direct attack of personnel and materiel by kinetic energy.Theenergetic material may also be transported tothe target for direct or indirect attack bychemical energy. The most commonapproach is the indirect attack of targets bythe chemical energy - using explosive to drivefragments (such as mortars and shells) orshaped-charge jets (such as LAW 80).

Weapon systems have harnessed the powerfrom explosive blast for many years. Earlyweapons used gunpowder until thedevelopment of high explosives such as TNT(2,4,6-trinitrutoluene). Military research hasfocused on improving the performance of high explosives to improve the effectiveness

of weapon systems. Explosives are generallythe principal means of harnessing enormousamounts of energy to attack a target. Whenthe warhead is initiated, the high explosivedetonates generating very high pressure

gasses which rapidly expand and do work ontheir surroundings. The work may beexpended in fragmenting the warhead case orforming a shaped charge jet; some of theenergy from the explosion manifests itself asa blast wave in the surrounding air.Traditionally, very few conventionalmunitions use the blast wave to directlyengage a target. One such example is an anti-personnel mine where there are few, if any,metallic components to act as fragments.The

primary output of the mine is blast and thiscan have a devastating effect on the limb incontact with the mine. Shaped chargewarheads are rarely used for attackingpersonnel; they are primarily designed todefeat armour but there are ammunitionnatures such as bomblets in artillerymunitions that combine shaped-charge jetswith a secondary anti-personnelfragmentation role to suppress infantry.

Fragmenting munitions (e.g. handgrenades, mortars and shells) are widely usedin conflicts because of their effectiveness

against a wide range of targets, includingpersonnel. Over time, there has been a shifttowards increasing the effectiveness of weapon systems by optimising theirfragmentation output: notched cases, wirewound cases, pre-formed fragments andspecially designed liners around theexplosive.

Warhead designers have been developingmeans of directing the explosive energy inwarheads to attack specific targets.Advancesin energetic materials have improved uponthe explosive performance of early explosivecompositions such as TNT to more modernPolymer Bonded Explosives which have anoutput of about 1.5 times that of TNT(based on pressure and impulse).

Most of the advances in energetic materialshave been towards improving theperformance of explosives for driving metal(fragments and shaped charges) with only asmall amount of development towardsimproving the blast performance.

There is now emerging evidence thatenhanced blast explosives have beendeveloped and are being used in a number of weapon systems. Until recently, blast was

only utilised in specialised weapons such asfuel-air explosive (FAE) air delivered bombs.Sales literature and other publicly availablepromotional literature indicates thatenhanced blast explosives are now being

Mr P Dearden B.EngAMIMechE

Scientific Leader,Vulnerability &Protection,DERA ,Porton Down,Salisbury,SP4 0JQ

E-mail:[email protected]

New Blast Weapons

P Dearden



used in a range of munitions from smallgrenades through to large calibre rockets.

This paper reviews the developments inweapons designed to attack materiel andpersonnel with blast. The informationpresented in this article is derived fromsources in the public domain. Beforereviewing these weapons, it is of value to

briefly consider the merits, or otherwise, of blast and fragmenting munitions.

Blast versus fragmentationFor a conventional high explosive charge, theenergy available in a blast wave decays veryquickly with increasing range. The decay of the blast wave is strongly influenced by theenvironment in which it is detonated - forexample the decay will be significantly less if the warhead is detonated within a structure,compared with one detonated in the open.Blast waves can diffract around corners and

the expanding gases can rapidly propagatethroughout a structure. Reflections fromsurfaces also increase the overall blast load toobjects within a structure, and upon thestructure itself. Blast weapons are effectivewhen used in confined spaces or built upareas.

Fragmenting munitions have a relativelyhigh casing/explosive mass ratio.The primarypurpose of the explosive is to create andpropel fragments. The lethal range of thesefragments is far greater than the lethal radiusfrom the blast generated by the explosive.However, the probability of being hit by one

of the fragments reduces significantly withrange as the fragments diverge in space.Fragmenting munitions are most effectivewhen used in the open. Obstacles such aswalls can provide significant protection bystopping or slowing down the fragments.Furthermore, fragments do not go aroundcorners, although they can ricochet.Fragmenting munitions are often used in asuppression role. Soldiers in battlefieldtrenches are well protected from artilleryshell fragments (unless there is a direct hit).

In current and future operations, collateral

damage will be a principal concern,especially with regard to personnel. In thesescenarios, the use of fragmenting munitionsmay be limited due to the indiscriminatenature of the fragment throw. Blast weaponsmay well offer the most effective means of providing low collateral damage munitions.Blast weapons have a well defined andlimited area of effectiveness due to the rapiddecay of the blast wave. Figure 1 shows howthe lethal radius of blast and fragmentingmunitions compare in the open.

Blast waves and targetsThe interaction of blast waves with targets iscovered in detail in another article in this Journal (Cullis). Blast is not ideally suited tothe attack of all types of target.When facedwith a main battle tank, one would probably

select a weapon such as LAW80 that is

designed to defeat the armour. However, if one was faced with enemy soldiers in aprotected structure then LAW80 would notbe the ideal choice – a shoulder-launchedrocket with a wide area of effect may be moreappropriate. Blast and fragmentingmunitions fall into this general purposecategory. Some targets such as personnel aresusceptible to a wide range of damagemechanisms (blast, fragments, thermal loadetc.).

FAE weapons with their relatively longimpulse and blast overpressures are ideallymatched to soft targets such as aircraft, un-

reinforced buildings, missiles, un-armouredvehicles, communication equipment andpersonnel.

Fuel-air explosivesA number of nations including the UnitedStates (US) and Former Soviet Union (FSU)have developed fuel-air explosive weaponsystems.The primary damage mechanism of such devices is blast. There is very littleprimary fragmentation associated with FAEweapons. Relative to conventional explosiveweapons, the blast output can be several

times greater. FAE warheads generallyrequire atmospheric oxygen to detonate.Thewarheads carry a liquid hydrocarbon that isdispersed in the atmosphere on initiation(the contents can either be explosivelydispersed or dispersed under pressure). Theun-detonated vapour cloud expands into theatmosphere mixing with atmosphericoxygen. At some pre-determined time afterdispersion, a second explosive charge isinitiated within the vapour cloud. Thisdetonates the vapour cloud generating astrong blast wave. The density of thedetonating medium is lower than

conventional explosives leading to lower blastpressures compared to conventionalexplosives. However, the cloud covers a largearea and so the effect of such a weaponcovers a considerably greater area than could

P Dearden 81

Fig 1. Comparative blast and fragmentation lethality radii

for a 900g warhead in the open.

Range (m)

Blast versus fragmentation

P l e

t h a l i t y



be achieved with conventional solidexplosives of a similar mass. Figure 2compares the fall of peak pressure withdistance for 1kg of TNT and 1 kg of EthyleneOxide (a fuel commonly used in FAEweapons).

The blast waves produced by FAEweapons differ from conventional high

explosives such as TNT. Close-in to theexplosion, conventional condensed militaryexplosives have a very high peak pressure anda relatively short duration. Close-in to FAEexplosions, the peaks pressures are lowerthan for TNT (Figure 2a, ‘a’) but theduration of the blast wave is significantlylonger. Because the blast wave from TNTdecays more quickly than FAE (Figure 2a,‘b’) it is less effective in the mid-field. Thepeak pressure of the blast wave inside the fuelair cloud remains fairly constant out to theperiphery of the cloud (Figure 2a, ‘c’) where

the blast then decays in a similar manner toTNT. Figure 2a shows that at mid to far fieldfrom the explosion, the pressure from theFAE system is much greater. Coupled withthis, the duration of the FAE blast waves aregreater (Figure 2b).The impulse (pressure xpresented area x time) is a measure of theability of the blast wave to do work on astructure; the impulse in the FAE blast waveis significantly greater than TNT.

Disadvantages of FAEAlthough this class of weapon appears tooffer many performance advantages, there

are problems associated with the design,storage and functioning of such a device. Toachieve the optimum output from an FAEweapon, it is important to ensure that thevapour cloud has reached the correct

stoichiometry (mixing with the air). At thatprecise time, a second explosive charge mustoperate to start the detonation process of thecloud. The evolution of the cloud could beaffected by atmospheric conditions, highwinds, rain and temperature extremes.Overall, the successful detonation of a fuel-air cloud can be a tricky procedure.

Today’s Blast Weapons

Fuel Air Explosive systemsThe US have a number of fuel air warheadsin their arsenal ranging from BLU-64/Bcarrying 200kg of a fuel through to BLU-72B Pave Pat 2 carrying 1,202 kg of ethyleneoxide (Jane’s Air Launched Weapons). TheUS have apparently limited their use of fuel-air explosive air technology to air deliveredbombs; they have had specialised FAEwarheads in their inventory since the 1960s

(Lavoie 1989).An article in the Sunday Times (Walker2000) suggested that the use of FAE bombswas threatened by the US during the Kosovoconflict. It was reported that the US sent avideo to Yugoslav army generals showing thedevastating effect of FAE weapons. It alsosuggested that the dramatic effects of suchweapons caused Slobadan Milosevic to re-consider his position.

The FSU have also developed a range of air delivered fuel air weapons such as ODAB-500PM (images on www.aeronautics.ru/nws002/janes014.htm) and KAB-500Kr.

The ODAB-500 PM bomb has beendeveloped by Russia to provide the RussianAir Force with a high speed low-level attackfuel-air explosive weapon for use againsttroops and material in the field. Both of these

82 New Blast Weapons

Fig 2b.Blast wave duration for 1 kg TNT and 1 kg Ethylene Oxide (FAE) Fig 2a. Overpressure for 1 kg TNT and 1 kg Ethylene Oxide (FAE).

Peak incident overpressure: FAE vs TNT

Increasing range Increasing range

I n c r e a s i n g

o v e r p r e s s u r e

I n c r e a s i n g

d u r a t i o n

Positive phase duration: FAE vs TNT



weapon systems are designed for the attackof blast-sensitive targets includingpersonnel. The ODAB-500 PM bombcontains 193kg of an unknown high energyexplosive fuel. It is claimed that the bomb’seffective range against infantry in the openis a 30m radius (almost 3000m2) (Jane’s AirLaunched Weapons).

An article in Jane’s Intelligence Review(June 1995) demonstrated how such aweapon could be used with devastatingeffect by ground forces. ODAB 500’s havealso been modified so that they can belaunched from the back of a vehicle ratherthan dropped from an aircraft. This weaponsystem was reported to have been used bySerbian forces to bombard Bihac.

China has also developed fuel-airexplosive cluster bombs. Jane’s AirLaunched Weapons reports that in 1990 twosizes of bomb were being developed: a250kg bomb carrying 2 bomblets and a500kg bomb carrying 3 bomblets. Themanufacturer claims that the destructionradius for a single bomblet is 30m foraircraft, 40m for mines and 50m forpersonnel (nearly 8000m2!).

A new generation of enhanced blast explosivesIn addition to traditional fuel-air munitions,it appears that Soviet scientists have alsodeveloped a new range of enhanced blastmunitions. Over the past decade there havebeen a large number of weapon systemsappearing that appear to deploy a newenhanced blast explosive technology. Anumber of descriptions, including volumetric

and thermobaric are being used to describewhat appears to be an advance in explosivestechnology. Volumetric appears to implysome form of advanced fuel-air explosivetechnology; thermobaric implies anenhanced blast explosive that also generates asignificant thermal output.

One of the first systems claimed to employthis new technology was the Soviet infantryflame-thrower RPO-A (Figure 3a and 3b).This is described in detail in Jane’s InfantryWeapons 2000-01. RPO-A is issued toairborne and marine assault troops to destroystrong-points such as bunkers or lightly

armoured vehicles. RPO-A (Russian name – Shmel) is a single-tube launcher normallycarried in pairs. It has a simple optical sightcalibrated to 600m.

The warhead is 93mm in diameter andcontains 2.1kg of a thermobariccomposition. Literature claims that whendetonated inside a structure, the destructiveeffects cover 80m3 (Jane’s Infantry Weapons2000). RPO-A is designed for the attack of blast-sensitive targets including personnel.This weapon was reported to have been usedextensively by the Russian army in the

Chechen conflict 1994-95. It is also reportedto be the most widely available thermobaricweapon (Leaf 2000).

RPO-A is without doubt a very valuableaddition to the Russian infantry weapons.For the first time, the infantry have the abilityto deliver remotely relatively large quantitiesof explosive to the target. This will allowthem to take on a much wider range of targets effectively, including personnel in theopen and in protective structures.

The smallest weapon system utilisingenhanced blast explosives is a magazine-fedslide-action grenade launcher, GM-94

(Figure 4). The launcher fires a variety of 43mm cartridges including fragmentation,shaped charge and thermobaric. Noperformance data for these small grenades isquoted.

P Dearden 83

Fig 3b. Pack of two RPO-A Shmel rocket infantry flame-throwers, as issued (T J Gander

2000).

Fig 3a. Pack of two RPO-A Shmel rocket infantry flame-

throwers (T J Gander 2000)

Fig 4. GM-94 43mm magazine grenade launcher (LHaywood 1999).



Recently more advanced weapon conceptshave been being marketed.The RShG-1 is amulti-purpose assault weapon designed todefeat lightly armoured vehicles, fieldfortifications and concrete structures. Asingle RShG-1 is claimed to be effectiveagainst personnel sheltered in confinedspaces of up to 300m3, or in the open with aradius of up to 10m.This weapon is thoughtto be in production and is offered for exportsales; it is probably in service with Russian

military forces (Jane’s Infantry Weapons).A number of warheads exist for the RPG

man-portable short-range rocket system. Afuel-air thermobaric warhead has now beendeveloped for the RPG (Figure 5). Thewarhead weighs approximately 4.5 kg andhas a maximum range of 700m.The warheadis claimed to be able to ‘disable personnel intrenches or bunkers (with the grenadedetonating 2m from the trench or bunker)’.It is also claimed that the warhead is effectiveover a 10m radius in open terrain (Jane’sInfantry Weapons).

Enhanced blast warheads have also beendeveloped for a range of guided missiles. AT-6 ‘Spiral’ is a helicopter launched anti-tankweapon and is believed to have a fuel-air orthermobaric type warhead (Figure 6). AT-9,a guided missile launched from a vehicleplatform, also boasts an FAE option for useagainst static targets. Kornet, AT-14, a longrange anti-tank guided weapon also can befitted with a enhanced blast warhead (Figure7). Metis-M is a crew served weaponoriginally designed for the attack of armoured targets (Figure 8). An updatedmissile has been developed that contains a

4.95 kg thermobaric warhead for the attackof bunkers and similar targets.

Khrizantema is a dual anti-armour/anti-

bunker weapon being developed by the KBPInstrument Design-Making Bureau (Figure9).The weapon can be mounted on a BMP-3 tracked infantry fighting vehicle and has arange of 6km. One of the warhead options isfuel-air explosive for the attack of bunkers(Jane’s Infantry Weapons).

Russia has also developed an enhanced

blast explosive warhead for their unguidedair-launched rocket range, S8. The variantS8-DM is quoted as having a 3.6 kg FAEwarhead.

Very few anti-ship weapon systems arereported to have been modified to takeadvantage of enhanced blast explosives.Thisis somewhat puzzling since blast is aparticularly effective damage mechanismagainst ships.

Probably one of the most devastatingweapon systems to deploy enhanced blastexplosive technology is TOS-1 ‘Buratino’(Figure 10). This is a purpose built weaponsystem designed to deliver a large payloadover a large area.The weapon system appearsto have been specifically designed to deployenhanced blast explosive technology. Russiansales literature states that ‘Fighting vehicleTOS-1 is designed for defeating the enemymanpower on the open country and indefences…’. It has a range of up to 5.5 kmand can launch 30 220mm rockets in under8 seconds (VTTV-Omsk-99) (Figure 11).The Buratino is reported to have been themain thermobaric delivery system that theRussians used against Grozny (Grau 2000).

TOS-1 may not be the only MultipleBarrel Rocket Launcher (MBRL) that iscapable of delivery enhanced blast warhead.


Fig 5.TBG-7V, a thermobaric warhead for the RPG-7 launcher (T J Gander).

Fig 6. MT-LB tracked vehicle with AT-6 launcher in elevated position

(Christopher S Foss).

Fig 7. Kornet launch unit (T J Gander).

Fig 8. Metis-M launcher with missile (T J Gander).



Two other MBRLs are believed to be able todeliver fuel-air explosive warheads, Splav220mm (Uragan) BM 9P140 220mmlauncher with 16 rounds and Splav 300mm(Smerch) BM 9A52 300mm launchercarrying 12 rounds (Jane’s AmmunitionHandbook).

DiscussionEnhanced blast technology is emergingacross a wide range of weapon systems. Smalldevices such as the 43 mm grenade launcherwith a range of a few tens of metres throughto long range MBRLs capable of delivering

large payloads over many tens of kilometres,are either in-service or under development.

It does not appear that these enhancedblast weapons are being developed anddeployed to replace conventional warheadssuch as fragmentation and shaped charge.They appear to have been designed tocomplement the current inventory. Russiaappears to be at the forefront of thesedevelopments and has probably gained agreat deal of experience through conflictssuch as Afghanistan and Chechnya. Theseexperiences may have led to their blastweapon development programmes which inturn has led to their emergence in service

and for purchase at arms fairs.Of key importance is the fact that

personnel are invariably within the targettypes quoted for these weapons. Blast is aneffective means of killing/incapacitatingpeople either by the direct effects of the blastwave on the body or by indirect effects suchas secondary projectiles, high thermal loads

causing burns, particularly to exposed skinsuch as the face, and crush injuries caused bythe collapse of structures. The principaldirect injury caused by the interaction of theblast wave is blast lung.This is a pulmonarycontusion produced by the pressure waveentering the thorax.The clinical sequelae andmanagement principles are discussedelsewhere in this Journal (Horrocks), but thisis a serious injury that may have both acuteand long-term effects on the militaryperformance of personnel, and may providesignificant clinical and logistic challenges formilitary medical services. The blast wavesmay also produce contusions andperforations to small and large bowel.

Although the performance of enhancedblast technology - fuel-air or thermobaric - isundoubtedly an improvement overconventional explosives such as TNT, there isno evidence that they offer orders of magnitude enhancements. They areemploying a damage mechanism that has notbeen fully exploited. Blast has a very clearlydefined lethal radius, and may be thesolution to many of the problems raised bythe current need to reduce collateral damage.

It is quite probable that future conflicts willinvolve Urban Operations. These types of weapon are well suited to this environment,thus it is more likely that UK forces willencounter them in the future.

Currently, protection issued to the armedforces is designed to stop bullets andfragments. Protective clothing such as theUK Combat Body Armour (CBA) is veryeffective at protecting against fragments, butin common with all vests of this general typeused by armed forces world-wide, it offers noprotection to the direct effects of blast on thebody. It is possible to significantly reduce theblast energy entering the body and thus the

P Dearden 85

Fig 10.TOS-1 (VTTV-Omsk-99). Fig 11.TOS-1 firing missiles in pairs (VTTV-Omsk-99).

Fig 9.The Khrizantema dual anti-armour/anti-bunker weapon system mounted on a BMP-

3 infantry fighting vehicle (1997). Taken from www.geocities.com/area51/capsule/6480/

at15htm.




incidence of injuries such as blast lung. Oneapproach is to use decouplers - layers of materials with different acoustic andmechanical properties that attenuate shockwaves. Protective clothing designed tomitigate the direct effects of blast does exist -for example, the UK Mk4 EOD suit - andresearch at DERA is underway to develop

protective clothing that is lighter in weight,more flexible and of minimal bulk.

There is now the potential to see asignificant change in the types of injuries infuture conflicts. The types of injury that wewould expect to see from enhanced blastweapons are not new per se, but the incidenceof injuries such as blast lung, burns andcrush may rise.There will be implications forthe Defence Medical Services in clinicaldoctrine, scaling of equipment and thetraining of staff.

SummaryEnhanced blast technology is apparentlybeing used in many weapon systems(principally of Russian origin) providingarmed forces and militia with a improvedability to engage a wide range of ‘soft’ targets,including personnel.Historically many of theinjuries experienced during conflicts werepenetrating wounds caused by fragmentationand bullets. Blast weapons have very littlefragmentation associated with them; thepayload is optimised to deliver the largestblast charge possible.The injury mechanismsassociated with these weapons are likely to be

the direct effects of the blast on the bodysuch a blast lung, burns to exposed skin andcrush injuries due to the collapse of buildings.These are not novel injuries per se,but their incidence will increase in operationswhere blast weapons are used.

It does not appear that enhanced blastweapons are being developed to replace

conventional fragmenting munitions; it ismore likely that their purpose is to expandthe capability of the fighting soldier. Blastweapons may be particularly suited to UrbanOperations where systems like RPO-A arereported to have been used (such as inChechnya). Blast may also be one of thepractical solutions to low collateral damage

weapons, by replacing fragmentingmunitions that have very large lethal areasdue to fragment throw.

With increased numbers of enhanced blastweapons being developed and marketed, it isbecoming increasingly likely that UK forceswill have to face them at some time in thefuture. The Defence Medical Services mustbe prepared for this challenge.

AcknowledgementsThe author would like to acknowledge theinformation and images provided by Jane’s

Information Group.

ReferencesGrau L, Smith T, A ‘Crushing’ Victory: Fuel-AirExplosives and Grozny 2000, http://call.army.mil/call/fmso/fmsopubs/issues/fuelair/fuelair.html.

Jane’s Air Launched Weapons, Update 6. Jane’s Ammunition Handbook, 2001-2002. Jane’s Armour and Artillery, 2000-2001. Jane’s Infantry Weapons, 2001-2002. Johannsohn G, Fuel Air Explosives RevolutioniseConventional Warfare, International Defense Review,6/1976.Lavoie L, Fuel-Air Explosives, Weapons, and Effects,Military Technology, 9/89.Leaf T,Thermobaric Weapons: A Weapon of Choice for

Urban Warfare, http://call.army.mil/call/ spc_prod/mout/docs/thermodoc.htm.ODAB-500PMhttp://www.aeronautics.ru/img001/odab500pm.htm.TOS-1 200mm Multiple Rocket Launcher, http://www.fas.org/man/dod-101/sys/land/row/tos-1.htm.VTTV-Omsk-99 http://www.rbs.ru/vttv/99/firms/kbtm/e-tos1m.htm.Walker T, Bomb video took fight out of Milosevic,Article Sunday Times, 30/1/2000.

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