By R. Braybrook, T. Gander & A. Preston

Depending on the service that uses them - Aviation, Army or Navy - pyrotechnics can be used to fulfil a variety of requirements. Generally used to conceal, they can also be used for quite opposite purposes, like illuminating a battlefield.

Fire from the Skies

Off-board decoys for aircraft were introduced by Britain in the form of anti-radar chaff in 1943, and as infrared flares by America around 1970. These low-cost expendables are still in use today, but work continues to make them even more effective.

Flares

In the 1991 Gulf War at least 15 Coalition aircraft were downed by man-portable infrared-guided missiles. This followed heavy Soviet losses to similar weapons in Afghanistan, by the end of which the Su-25 had been given eight 32-round flare-dispensers, sufficient for eight passes.

The British RAF's Tornado F3 demonstrates the use of the Vinten Vicon 78 Series 400 countermeasures dispensing system.

BAE Systems' Integrated Defense Solutions (formerly Tracor) claims to be the foremost developer and producer of aircraft flares. Like the company's chaff products, these are ejected from IDS' own dispensing systems, such as the Ale-40 and -45. The Ale-47 is described as the most advanced of countermeasures-dispenser systems (CMDS), with over 2500 installed in the aircraft of 20 nations.

Britain's Vinten produces the Vicon 78 CMDS, which dispenses standard Nato payloads from a wide range of aircraft, and has been selected for the Nimrod MRA4. Wallop Defence Systems (part of Flight Refuelling) is the prime manufacturer for infrared decoys for Britain's RAF, and its HotSpot family of round- and rectangular-section flares are in service around the world. Its 55 mm No2 Mk 1 cartridge has been selected for the Eurofighter 2000.

In the West there is concern that helicopters may be inadequately protected. Their current flares were mainly developed for jet aircraft and are thus undesirably powerful. A recent study by Chemring Countermeasures (a division of Pains Wessex), the design authority for UK chaff and flares, concluded that the company's PW118 flare generates a peak output twelve times the tail-aspect emission of a large helicopter, and 120 times that of a small one.

This imbalance gives the missile seeker a means to distinguish a flare from the target aircraft. Chemring Countermeasures has now developed a 60-shot Modular Expendable Block (MEB), which is available in both infrared and chaff forms (or with a combination payload), and occupies the same space as a conventional 30-shot magazine. The MEB appears to follow on conceptually from the Lacroix Barrette, in which flare cartridges are fixed at their bases to an expendable metal frame.

The peak output power of the new Chemring 13 mm IR MEB flare is one-third that of the PW118. Another example of a modern reduced-output flare is the 40 mm Lacroix Pyrotronics Type 595, which is fitted to French Transalls, using the Alkan 507 dispenser.

Although most external chaff/flare installations are aerodynamically crude, improved designs are illustrated by the Per Udsen Pylon-Integrated Dispenser System (Pids) for the F-16 and the Pylon-Accommodated Self-Protection Suite (Pass) for the F/A-18. Both combine dispensers, missile warning systems and the Therma Elektronik ALQ-213(V) Electronic Warfare Management System.

In the case of a new aircraft design, an internal integrated electronic warfare system can be designed from the outset, as instanced by the Matra BAe Dynamics Spectra for the Dassault Rafale. The company is also responsible for the Spirale and Éclair-M systems for the Mirage 2000. Its Alkan subsidiary produces a range of dispenser systems, including the Spirit for the C-130 and Transall, and the Elips for the Cougar Mk 2. The Elips uses the Lacroix Helir family of 19 mm cartridges, consisting of the infrared Verdite and the Junon chaff rounds.

A widely-adopted installation is the SaabTech Electronics Bol, which is designed to use empty space in an air-air missile launch rail. In this case, chaff packs and infrared material are dispensed mechanically. The Bol is marketed internationally by Saab, BAE Systems, Chemring Countermeasures and Alloy Surfaces.

Two SaabTech Electronics Bol dispensers are shown next to one integrated into a launch rail for the AIM-120 Amraam air-to-air missile.

Advances in infrared missile seekers are expected to lead to the aircraft defending itself with a combination of flares, probably in the form of a traditional burning free-fall flare, a rocket-powered kinematic flare such as the BAE Systems MJU-47/B or -48/B to fly ahead of the aircraft, and a third that is spectrally-matched to aircraft type. The MJU-48/B ejects non-burning pyrophoric wafers, which heat up when in contact with oxygen. The pyrophoric process was patented by Alloy Surfaces, which makes the MJU-27/B flare for US Navy applications, the -50/B for transports and helicopters and the -51/B for fighters.

Interest in spectral matching was evidenced by a French government-funded Lacroix study in the mid-1990s termed Lisa (Leurre Infrarouge Signature Adaptable). This was run in parallel with the Lica (Leurre Infrarouge Cinétique Adaptable) study of 40 mm and 60 mm flares that were towed or equipped with wings and either rocket-powered or released in free flight.

The SaabTech Electronics BOP/B pyrotechnic dispenser was designed to be scabbed on to the aircraft, or fitted as a pylon extension.

Work by Canada's Defence Research Establishment Valcartier has led to the development of flares using pyrophoric liquids to defeat spectrally-discriminating two-colour missile seekers. The MJU-5188/B flare was developed for the CF-18 Hornet, and the MJU-5130/B for the CC-130 Hercules. Flight trials began in 1996, and a production order is expected to be signed shortly. The flare is ejected from the dispenser by a squib, but its base is retained and remains connected to the flare by a wire. When this wire becomes taut, it ignites a gas generator in the flare, moving a piston that expels the pyrophoric liquid through a nozzle, to ignite spontaneously on contact with the air. The prime contractor is Bristol Aerospace and its principal subcontractor is SNC Technologies.

It may be noted that flares are also manufactured to produce high intensity flashes that blind electro-optical sensors and laser beam guidance systems. One example is the Lacroix Pyrotronics Type 685, a 60 mm flash cartridge meeting a French Air Force requirement for the Matra BAe Dynamics Sycomor pod.

Airborne flares are also employed to illuminate targets and personnel waiting to be rescued. Thiokol products in this category include the LUU-19 near-infrared flare for covert illumination and the M-278 near-infrared flare, which is delivered by a 70 mm Hydra rocket.

Chaff

To defeat surveillance radars, chaff can be employed to provide a safe corridor for following aircraft, and to create false targets that confuse ground defence systems. As a self-protection device against surface-based and missile-mounted tracking radars, chaff is best used in conjunction with an evasive manoeuvre.

Modern self-protection systems take information from aircraft sensors (notably the radar warning receiver), and automatically dispense a computed amount of chaff at the optimum time. An important element in this system is a 'smart' dispenser that communicates its payload to the computer.

Although chaff is now generally dispensed as cartridges, Lacroix also markets chaff rocket heads to generate false radar targets ahead of the aircraft. Another form of dispensing was used during the later stages of the 1982 Falklands Conflict, when Royal Navy helicopters employed manually-released Chemring Chaff Broadband to minimise the threat of radar-homing Exocet missiles to surface vessels.

Chaff normally takes the form of aluminium-coated glass filaments or dipoles of around 25 microns diameter, cut to different lengths to respond to a variety of radars. Each filament resonates strongly when it receives a radar emission with a wavelength equal to twice its length. Rapid blooming of the chaff is important in creating an apparent radar target close to the aircraft. Blooming is assisted by locating the chaff dispenser in the region of the wingtip, to exploit the scattering produced by trailing vortices.

One widely used chaff cartridge is the Chemring RR170. Designed to suit the Ale-40/47 and M130 produced by BAE Systems (the only manufacturer of chaff in the US), the Vinten Vicon, Rokar and Matra/Alkan dispensers, the RR170 can generate a radar cross-section of 700 square metres at a frequency of three GHz.

Modern chaff-dispensing systems are digital, giving better integration with aircraft sensors and making possible much shorter intervals between cartridges. These intervals are now measured in tens of milliseconds (rather than hundreds), allowing the use of greater numbers of lighter chaff shots.

Recent British trials have indicated that the number of chaff dipoles in a cartridge can be significantly reduced without a loss of radar cross-section. The development of smaller chaff payloads matches Chemring's smaller infrared cartridges (discussed earlier) and associated Modular Expendable Blocks (MEBs). The chaff version of MEB is now in service on the Puma, Sea King, Chinook and Lynx helicopters. A smaller eight-shot MEB is to be used in a Vinten dispenser on the British Army WAH-64D.

The defensive aids suite for the Boeing C-17 combines the Hercules AAR-47 missile approach warner and the BAE Systems ALE-47 dispenser system.

Light Up the Stage!

Land forces utilise pyrotechnics for many reasons. Leaving aside the use of smoke for screening or concealment purposes, the main tactical applications for them are attracting attention and illumination. Pyrotechnics are therefore rarely deployed as active weapons but as support devices, indicating locations of tactical importance or enabling weapon operatives to observe targets at night.

The Chemring chaff package for the Bol dispenser is an 8 mm-thick slice, consisting of multiple subloads. The Bol contains 160 or more such packages.

Pyrotechnic attention attraction devices are several in character. They vary from coloured smokes to 'sentry' devices that indicate intrusions by bang/flash results following the activation of a tripwire or some other triggering method. Included in the range are coloured smokes for signalling and simple flares that can be used as individual or unit location indicators, or as tactical warning or emergency signals. Any nation with the capability to manufacture display fireworks can produce such military pyrotechnics. The techniques involved are not so incredibly advanced, as they date back to before the introduction of black powder-based explosives during the Middle Ages, so pyrotechnics rarely change much in design or display any great technological innovations. Firework-based pyrotechics, such as Thunderflashes, remain among the most widely-employed of all military stores, with applications from tactical training to creating distractions during combat.

The Matra BAe Dynamics Saphir self-protection dispenser for helicopters can accommodate from 18 to 72 cartridges, depending on their size.

Smokes

Smoke generation devices come in several forms, varying from the so-called smoke pots to grenades. The traditional use of smoke has always been to screen activity from enemy vision but by introducing coloured smokes it becomes possible to employ smoke to denote target or unit locations, indicate para-drop or landing zones and to deliver simple signals. Most coloured smoke grenades differ little from conventional smoke grenades, having some mixture of smoke-producing compound held within a 'beer can' canister to be activated by a simple mousetrap ignition device as it is thrown. After a delay of a few seconds most hand grenades will emit coloured smoke for almost a minute and a half.

Buck, now operated under the auspices of Germany's Rheinmetall and Switzerland's Ruag, has pushed the art of pyrotechnics quite far into the art of coping with various spectra and thereby with both the human eye and infrared sights and seekers as indeed what a soldier might not see behind a thick screen of smoke, his thermal sight will. The Buck Maske grenade (available in 66, 76 and 81 mm calibres) offers instantaneous jamming and screening in the complete infrared and visual wavebands.

Also famous for its vehicle self-protection grenades is Etienne Lacroix of France which produces the Galix system with Giat. As part of the KCBM study, the latter is integrating the Galix in an overall vehicle self-protection suite.

Some grenades and smoke pots may have friction igniters while smoke grenades fired from grenade launchers, such as the 40 mm grenade launchers slung under assault rifles, usually have percussion fuzes. Relatively few of the latter have been introduced, and those usually for target marking, as their payload capacities are limited to producing smoke for only about 40 seconds, at best.

Perhaps the current 'classic' coloured smoke hand grenade is the M18, still in production in the United States by Allied Techsystems (ATK), Kilgore Operations. The hand-thrown M18 has been used as the basis for similar grenades produced in South Korea, the Philippines and Iran, to name but a few, while many other grenades, such as those produced in South Africa by Swartklip Products, are variations of the simple M18. They include grenades from Nico Pyrotechnik of Germany, Chartered Pyrotechnic Industries of Singapore, Expal of Spain, and Haley and Weller of the United Kingdom, again to mention but a few.

The Nico Pyrotechnik range of pyrotechnic devices including (top right) the Nicosignal flare kit, (top left) signal flare cartridges and (bottom right) mini flare kits.

Flares

Mentions of flares introduces visions of Very pistols firing signal flares for any number of reasons, from distress situations to delivering fire orders or attack warnings, the latter including chemical agent attack. Other flare delivery methods include the little hand-held 'fountain pen' launchers, and friction-ignited tubes propelling the flares using a small explosive charge or rocket motor.

Signal pistols, usually with calibres from 25 up to 38 mm, remain popular as they can deliver a wide array of possible star signals and may also be used to launch illumination flares. Their shotgun-pattern metal or cardboard cased cartridges can deliver all manner of coloured stars or combinations of stars to assist unit identification and transmit specific signals. Depending on local conditions and the size of the cartridges involved, the resultant signals can be observed over a wide area with a radius of up to eight kilometres at night.

Most small arms manufacturers produce durable and reliable signal pistols, typical being Heckler and Koch who produces a 26.5 mm single-shot pistol capable of firing the many signal cartridge products of Nico Pryrotechnik, Comet (Diehl Group), and Piepenbrock Pyrotechnik, all of Germany, although similar products from many other countries could be fired.

The spectacular results produced following the ignition of a Pains-Wessex A603 trip-flare kit.

Several of these latter concerns also produce miniature 'fountain pen' launchers and flares on which a hand-held, spring-loaded launcher fires a small flare body from a cup at one end. The flare bodies have calibres of about 16 mm so are limited in height and burn time performance. They are gradually being replaced by miniature flare kits in which the flare bodies are held in a loading block or body that may, in some cases, be converted to become a launcher. A typical example of the latter is the Nicosignal flare kit from Nico Pyrotechnik on which revolving magazines holding six flares can be attached to a hand-held launcher. The Pains-Wessex Miniflare kit involves a carrying block containing eight screw-on cartridges that are inserted into a small launcher tube cup prior to use (it is to be noted that Pains Wessex, Schermuly and Haley & Weller have recently joined forces and formed a new company called PW Defence).

Most pistol-delivered flares are free-falling and of short duration. The larger flares can be suspended under small parachutes to ensure they remain airborne for longer periods. These are usually delivered from hand-held tubes, sometimes with the benefit of rocket assistance. The single-shot tubes can be friction-ignition activated by a short cord at the base of the tube. Typical of these is the Pains-Wessex 38 mm hand-held rocket that can deliver a wide choice of flares, some suspended under small parachutes, together with maroons to attract further attention or as a signal. Similar devices, such as the Asatox chemical agent warning device produced by Lacroix of France, also emit an unmistakable shrill whistle to denote the onset of a chemical agent attack. In Germany, Comet produces hand signal flare delivery cartridges, as does Piepenbrock Pyrotechnik. Swartklip Products of South Africa also makes rocket-propelled alarm flares with the unusual innovation of a training version that fires an inert body and is thus unlikely to initiate unwanted emergency responses.

Other flare delivery systems exist, including artillery and mortar projectiles. Mecar of Belgium manufactures a muzzle-launched parachute flare rifle grenade while Israel Military Industries includes an infrared parachute flare in its rifle grenade family. 40 mm spin-stabilised signal grenades have been devised, especially in the USA, but few are currently in service.

A rocket-assisted parachute flare produced in Iran.

Sentries

Sentry or alarm flares follow a general pattern of a canister secured to a stake, tree or structure. A trigger mechanism on the canister is actuated via a tripwire or pressure pad so when an intruder activates the device a loud aural report is produced, sufficient to wake even the sleepiest guard, and the immediate area is rapidly illuminated by a bright flare. Further flares may be launched skywards to emphasise the point of intrusion even further.

This interesting sequence of photographs from Buck shows how the Maske grenade operates - as seen by an infrared camera.

For many countries, the US M49A1 surface trip flare acts as the prototype. In production by ATK, the M49A1 is issued as a kit complete with the flare canister, a mounting bracket and a 15 metre coil of tripwire; for some applications a metal picket is available. The bracket enables the flare body to be secured to a stake or structure and the trigger mechanism may be activated by the tripwire being either pulled or severed. The M49A1 is copied direct in Iran and South Korea (by the Hanwha Corporation), while essentially similar devices are offered by Haley and Weller (the E190) and Pains-Wessex (the A603) of Britain, Nico Pyrotechnic of Germany and Chartered Pyrotechnic Industries of Singapore. Many other nations produce similar devices.

The Russian PK-2 decoy despenser system carries two Zif-121 launchers that fire TSP-47 chaff, TST-47 infrared (the effect of which can be seen on the right) or TSO-47 'visual-optical' rounds.

Naval Pyrotechnics

The naval use of pyrotechnics was at one time confined to target-illumination and camouflage (smoke screens), but the advent of the heat-seeking missile changed all that forever. Today pyrotechnics in the form of infrared (IR) decoy flares are an essential element of self-protection systems, and the only debate is over means of deploying such decoys. Another irreversible change is to integrate such systems into the ship's combat management system.

A Canadian CC-130 deploying the MJU-5130/B pyrophoric decoy flair developed by the Defence Research Establishment Valcartier in Quebec.

The French Navy uses the Système d'Autodefense pour la Guerre Infrarouge et Electromagnétique (Sagaie) AMBL-2A as a long-range decoy-launcher capable of firing parachute-suspended sub-munitions. It equips the CVN Charles de Gaulle, the Cassard class DDGs and the Italian Maestrale class frigates, among others. It complements the shorter-range Dagaie Mk 2 AMBL-1B system, which is suitable for smaller warships. Decoy rounds are contained in 34-round Type C 'suitcases', and a delayed-action mechanism ensures that the cloud is co-located with the chaff cloud. Each IR decoy burns for 30 seconds, the emitting surface covering 360 metres2 at an altitude of 15 metres.

The German Buck Neue Technologien Giant IR seduction round has been adopted by the US Navy (as Mk 245), the Royal Navy and six others. Each sub-munition contains a three-part pyrotechnic payload: a mixture of warm smoke (for 8 to 14 microns), glowing particles (for 3 to 5 microns) and gaseous radiation (for 4.1 to 4.5 microns). Buck claims that these rounds are effective against scanning and imaging seekers, including two-colour types.

All front-line navies fear the 'beaconing' effect of on-board decoys, whether chaff or infrared flares. The Royal Australian Navy took the lead some years ago with the Nulka, an offboard delivery system using the Winnin hovering rocket. The purpose of the hovering rocket is to generate a cloud of decoys moving at a sufficiently slow rate to simulate the target-ship, and once that is achieved, the payload can be varied to suit tactical requirements. The US Navy liked it sufficiently enough to develop it as the Mk 234 system for amphibious ships.

The Sea Gnat is a Nato collaborative programme based on the US Navy's Super Rapid Blooming Offboard Chaff (SRBoc) launcher. Its Mk 218 infrared decoy round was abandoned and later replaced by the Giant. As an interim measure Wallop Industries' Barricade system was shipped, as it offered the only defence against heat-seeking missiles at the time. The Royal Navy designates Sea Gnat DLB and DLJ, and has apparently ordered an infrared flare round from Chemring, the well-known supplier of payloads. Its offboard solution is BAE Systems' Siren (DLH), which fires a parachute-suspended round. The round activates itself 10 seconds after launch at a pre-set range of 400 to 500 metres.

The manufacturers of the French Mistral heat-seeking missile claim that it can 'see' through decoy flares, but the new Chemring round is understood to be opaque to the Mistral seeker. This would require a much more sophisticated pyrotechnic round than anything known to exist previously. It may be no more than a coincidence, but Chemring has just bought the American flare-manufacturer Kilgore from Alliant Techsystems.

Tracor (purchased last year by BAE Systems) makes a Shipboard Countermeasures Interface Package (SCIP) for Mk 33 and Mk 36 launchers for export, handling both 113 mm and 130 mm cartridges. The 130 mm Tactical Distraction IR (TDIR-130) round is its main pyrotechnic product, but it also makes 66 mm and 76 mm smoke/obscurant grenade-launchers.

The US Navy also uses the SRBOC Super Gemini combined radio-frequency/IR round, and the Mk 186 Torch IR decoy, which continues to burn after landing on water. There is also an Advanced Torch Decoy (Mod 3), but this is likely to be superseded by the Mk 245 Giant.

With the end of the Cold War and the upsurge in sales of ships and equipment to export customers, we now know more about Russian flare decoy systems. The PK-2 (Zif-121) trainable 152 mm twin-tube launcher is assumed to be capable of launching an IR decoy round, as well as a 140 mm TST-47 IR decoy, weighing 38.5 kg at 1.1 metres long. The PK-2 is the oldest decoy-launcher in Russian service, and was for many years the only such system fitted.

The PK-10 is a lightweight 10-tube 120 mm barrage decoy-launcher designed for the Udaloy class destroyers. It fires the SOM-50 flare and aerosol IR decoy, the SK-50 combined chaff/IR decoy round, and an infrared/laser/optical decoy is said to be under development. PK-16 is an East German-designed launcher using sixteen 82 mm tubes. Its 653 mm long TST-60U IR decoy round weighs 8.5 kg.

As the virtual inventors of soft-kill systems capable of defeating anti-ship missiles, the Israelis have a considerable reputation. In addition to trainable launchers, the majority of Israeli Navy fast attack craft have twin tubes flanking the bridge, firing smoke rounds to defeat electro-optically guided weapons.

As knowledge of decoy systems proliferates, many of the smaller navies continue to develop indigenous systems to generate local expertise, but in most cases they rely on the well-established manufacturers to supply the payload. Japan's Maritime Self Defence Force (MSDF), the Republic of China Navy and the Republic of Korea Navy, for example, rely heavily on American expendables. The Royal Swedish Navy uses the CelsiusTech Philax launching system (also produced by the former MEL company in Britain as Protean). The Philax 106 has an IR decoy capability. The first five IR grenades are fired at a range of about 10 metres, then two groups of eight are deployed by parachute, merging with the chaff cloud at an altitude of about 10-15 metres above the sea. Reaction time is about two seconds, resulting in an IR target of about 150 metres in length. The 4.5 kg IR payload burns for about 25 seconds, working in the 3 to 5 and 8 to 14 micron bands. The Bofors division of CelsiusTech also makes 57 mm and 103 mm IR decoy rockets, for launching from rails on the sides of gunshields or stand-alone launchers. The former are launched on command from the fire control system, the latter are linked to the ship's electronic warfare system.

Space does not permit more than a passing reference to air-launched IR flares, mainly by land-based and shipborne helicopters. These are, in virtually all cases, merely the naval equivalent of airborne systems used by air forces. Shipboard helicopters are also equipped with more conventional illuminant flares for such operations as search-and-rescue (Sar).

Submarines have used smoke candles for many decades, as a simple method of revealing their presence during joint exercises, and today they still rely on pyrotechnics for smoke signals, either as a distress call in case of a serious accident or as a simple method of communicating with surface warships. Modern signal-ejectors can select colours for a pre-arranged coding system.

Flare decoys are developing rapidly, to match improvements in heat-seeking missiles. The solution must now be tailored exactly to the expected threat, which causes a headache for the US Navy and its allies. Today's enthusiasm for peacekeeping and intervention in local wars means that ships can be attacked by a variety of threats, emanating from more than one country's inventory. To react to such a spread of weapons the defending navy must have a full range of capabilities. No wonder that Western commanders are sometimes nostalgic for the certainties of the Cold War.