EP0399907B1 - Ammunition for spreading an incendiary mixture - Google Patents

Description

The invention relates to the field of jettisonable charges, for example, from an aircraft to which they are attached and in particular an ammunition containing an incendiary gel consisting of hydrocarbons and gelling agents, and intended to develop an effect. incendiary on various ground targets.

Ammunition containing incendiary gels made up of a mixture of volatile hydrocarbons (Kerosene, essences ...) and gelling products (fatty acid derivative) allow, after impact on the ground, a distribution and adhesion of these gels on different ground targets.

Ammunition intended to develop an incendiary effect has certain similarities to the ammunition known as fuel bombs. The patents US-A-4,141,294 and 3,955,509 which will subsequently be called D₁ and D₂ describe such bombs.

The similarity stems from the fact that fuel oil bombs and incendiary bombs have a reservoir containing the active material. The desired effect is achieved in these two types of ammunition by dispersing the active material. But this dispersion alone is not enough. Action must still be taken on this matter. In the case of the fuel bomb as explained in document D₁, column 2, lines 15-22 and in document D₂, column 4, lines 56-60, the action is a firing by shock wave and this firing must be carried out at a precise moment of the dispersion so that the desired effect, the detonation of the air-fuel mixture, can occur.

In the case of the incendiary bomb the action is a combustion of the incendiary mixture. This combustion is carried out by combustion elements, over a period of a few seconds. Since these munitions are generally not aerodynamically stable, they have poor precision. During the impact on the ground, the distribution of the incendiary gel is random since the ammunition dislocates under the effect of the shock, thus causing an ejection of the incendiary gel by puddles. This impact also sets off a firing rocket which generally ignites phosphorus, the projection of which, after impact, ignites only part of the puddles of incendiary gel.

As regards the dispersion of the incendiary gel, it is planned according to the present invention to achieve it not by simple dislocation and ballistic effect as in the prior art, or by pyrotechnic effect by means of a low-power explosive as described in document D₁ (column 4, lines 64-68 and 5, lines 1-3) but by firing propellant bread.

The object of the invention is to create a munition in which an incendiary gel is distributed, before impact on the ground, to ensure better dispersion of said incendiary gel, the latter being preferably lit by means of ignition means operating from the dislocation but also after the impact on the ground.

The subject of the invention is a munition according to claim 1.

• figure 1, un schéma d'une munition équipée selon l'invention ;
• figure 2, une coupe transversale AA' de la munition de la figure 1 ;
• figure 3, une coupe transversale BB' de la munition de la figure 1 ;
• figure 4, une coupe transversale CC' de la munition de la figure 1 ;
• figure 5, un schéma d'une canne pyrotechnique entourée de ces différents éléments.

The invention will be better understood with the aid of the following description, given by way of nonlimiting example and illustrated by the drawings which represent:

• Figure 1, a diagram of a munition equipped according to the invention;
• Figure 2, a cross section AA 'of the munition of Figure 1;
• Figure 3, a cross section BB 'of the munition of Figure 1;
• Figure 4, a cross section CC 'of the munition of Figure 1;
• Figure 5, a diagram of a pyrotechnic rod surrounded by these different elements.

• une ogive A avec une fusée et un proximètre ;
• un réservoir B proprement dit avec son équipement ;
• un retreint de culot C avec un empennage fixe et un parachute.

Figure 1 shows the diagram of the munition equipped according to the invention. This munition is made up of the following main parts:

• a warhead A with a rocket and a proximeter;
• a tank B proper with its equipment;
• a constriction of base C with a fixed tail and a parachute.

• une fusée 3 déjà utilisée sur d'autres munitions, montée sur un support entraîné en rotation par une hélice 4 ; cette fusée 3 est constituée principalement d'éléments non représentés sur cette figure :
  • . un turbo-alternateur fournissant l'énergie électrique ;
  • . un module proximétrique, par exemple, à rayonnement électromagnétique permettant de déclencher la dislocation à une hauteur déterminée au dessus du sol ;
  • . une chaîne pyrotechnique d'initiation ;
  • . un barillet de désalignement de chaîne ;
  • . un dispositif de sécurité d'éloignement de l'avion ;
• un porte-fusée 1 positionnant la fusée 3 de façon à ce que le rayonnement de l'antenne du proximètre ne soit pas perturbé par la présence de la masse métallique ;
• un carénage 2, par exemple, en un matériau plastique à l'intérieur duquel est fixé un dispositif rétracteur 5 d'une sécurité largable d'ogive SLO autorisant après le largage la rotation d'une hélice 4 et du turbo-alternateur, et, au centre de laquelle est positionnée, entre le début d'une canne pyrotechnique d'allumage 7 et le porte-fusée 1, un bouclier 6 qui assure l'interruption de la chaîne pyrotechnique.

Each of its parts has different elements which will be described below. The warhead A, for example made of composite material to avoid the action of metal on a proximeter, comprises:

• a rocket 3 already used on other munitions, mounted on a support driven in rotation by a propeller 4; this rocket 3 mainly consists of elements not shown in this figure:
  • . a turbo-alternator supplying electrical energy;
  • . a proximetric module, for example, with electromagnetic radiation making it possible to trigger the dislocation at a determined height above the ground;
  • . an initiation pyrotechnic chain;
  • . a chain misalignment barrel;
  • . an aircraft safety device;
• a stub axle 1 positioning the stub 3 so that the radiation from the proximeter antenna is not disturbed by the presence of the metallic mass;
• a fairing 2, for example, made of a plastic material inside which is fixed a retractor device 5 of a jettable safety of SLO warhead authorizing after the release the rotation of a propeller 4 and of the turbo-alternator, and, in the center of which is positioned, between the start of a pyrotechnic ignition rod 7 and the stub axle 1, a shield 6 which ensures the interruption of the pyrotechnic chain.

• une poutre interne 8, par exemple, en alliage d'aluminium de longueur déterminée ayant, par exemple, la forme du quart d'un tube circulaire ; cette poutre reçoit des anneaux 9, par exemple, vissés dans des puits 30 pour permettre l'accrochage de la munition sous un aéronef. des plaques d'appui 31, par exemple, en acier, renforçant le réservoir au droit de l'accrochage sous l'aéronef. Elles sont destinées à supporter les efforts pendant l'emport. A l'endroit de l'accrochage sortent deux câbles de sécurité, un câble de sécurité largable ogive SLO et un câble de sécurité largable culot SLC, permettant d'une part l'activation de la fusée de mise à feu en ce qui concerne la SLO et d'autre part, le verrouillage du parachute à la structure du réservoir ainsi que le déclenchement du retard de la commande de libération du parachute pour ce qui est de la SLC. Chacun de ces câbles de sécurité n'est opérationnel qu'au cours du largage de la munition. En effet, après accrochage de la munition sous aéronef, la traction de chacun des câbles (SLO, SLC) ne peut déclencher la mise en oeuvre des différentes étapes précitées car chacun de ces câbles est muni d'un dispositif de sécurité positionné à l'endroit où sortent ces câbles de manière à interdire tout mouvement de ces derniers. Ce dispositif de sécurité est muni, par exemple, d'une palette 32 maintenue en position fermée avant accrochage sous aéronef par une épingle de sécurité 11 et une bille non représentée sur cette figure 1 positionnée sur chacun des câbles de façon à pouvoir heurter la palette lorsqu'une action est exercée sur l'un des câbles et ainsi donc l'entraîner afin de libérer le mouvement du câble. Lorsque la munition est positionnée sous l'aéronef, l'épingle de sécurité 11 est retirée, la palette peut donc basculer sous l'action de la bille fixée sur le câble mais son mouvement est bloqué par le pylône de l'aéronef sur lequel s'immobilise la palette ; la course du câble n'est pas suffisante pour déclencher l'une des opérations précitée et son action n'est efficace qu'au cours du largage de la munition, lorsqu'une traction est exercée sur le câble. Les deux câbles de sécurité SLO et SLC coulissent respectivement dans les canaux 10 et 12 jusqu'à des dispositifs rétracteurs 5 et 26 situés dans l'ogive A et le retreint du culot C ;
• un orifice de remplissage 13 adapté aux moyens d'avitaillement aéronautique en service dans l'OTAN ;
• des cadres de renforts 14 dont certains servent de pare-flots ;
• un niveau automatique 15 permettant de stopper le remplissage ;
• une valve de dépressurisation 16 ;
• une pompe 17 avec tuyauterie de refoulement 18 pouvant être actionnée de l'extérieur, par exemple, par un moteur électrique, destinée à assurer l'agitation du mélange (hydrocarbure + liquide gélifiant) pour permettre une homogénéisation des composants grâce aux tourbillons générés par la turbulure de sortie. En effet, le moteur électrique donne à la pompe un débit et une vitesse créant un tourbillon en hélice qui facilite le mélange de l'hydrocarbure et du produit gélifiant. L'utilisation d'une telle pompe facilite par contre le manipulation de la munition avant son accrochage sous l'aéronef en permettant le chargement de l'hydrocarbure après la fixation de la munition sous l'aéronef en obtenant un mélange d'aussi bonne qualité qu'un mélange réalisé avant son insertion dans le réservoir de la munition ;
• une canne pyrotechnique 19 qui traverse le réservoir d'un bout à l'autre sur son axe de symétrie XX'. Elle reçoit d'une part un cordeau pyrotechnique 20 permettant les mises à feu des pains de propergol 21 et 22 placés à l'avant et à l'arrière de la munition et illustrés sur la figure 3 qui représente une coupe transversale BB' de la figure 1 ; ces pains de propergol 21 génèrent la pression interne qui assure la dislocation du réservoir ; la masse et l'emplacement de ces pains sont optimisés de manière à obtenir une ouverture en pétales (masse plus importante à l'avant qu'à l'arrière) ; ces pains 21 sont placés, par exemple, de façon circulaire à l'intérieur d'une enveloppe 33 en liaison avec le cordeau pyrotechnique 20 constitué de trois éléments par l'intermédiaire des trous 34 à l'intérieur de la canne pyrotechnique 19 permettant la transmission des ordres de mise à feu aux différents pains de propergol, et d'autre part aux capsules d'allumage de gel 23 représentées à la figure 4 qui illustre une coupe transversale CC' de la figure 1 ; ces capsules d'allumage 23 sont mises à feu par le cordeau pyrotechnique et sont expulsées de la canne pyrotechnique 19 sur laquelle elles étaient fixées, par exemple par vissage ; les capsules d'allumage 23 possèdent des moyens de guidage, par exemple, des ailettes 35 représentées en pointillés sur la figure 4 ; elles contiennent également des éléments de combustion 36 mis à feu par le cordeau pyrotechnique et dont la durée de combustion, de quelques secondes, permet d'allumer le mélange pendant la formation du nuage, pendant la chute des particules et après épandage au sol, si nécessaire. Le nombre, la taille et l'emplacement de ces capsules 23 sont définis pour obtenir un allumage parfait du mélange répandu après dislocation du réservoir. Ces capsules sont réalisées, par exemple, en alliage léger. A l'intérieur de la canne pyrotechnique 19 et comme représenté sur les figures 1, 2, 3, 4 et 5 est située une tringle 24 à l'arrière de laquelle est attaché un parachute 27 ; cette tringle 24 est reliée, à l'avant, à la commande d'effacement du bouclier 6 qui interrompt la chaîne pyrotechnique de mise à feu et qui empêche la mise à feu du cordeau pyrotechnique 20. La tringle 24 est immobilisée dans la canne pyrotechnique 19 par une goupille de cisaillement 39 qui interdit tout déplacement du bouclier 6 auquel elle est reliée par un levier 37 avant une traction exercée sur la tringle 24 après le déploiement du parachute 27 ; cette traction permet le coulissement de la tringle 24 à l'intérieur de la canne pyrotechnique 19 et déclenche le pivotement du bouclier 6 autour d'un point 38. A cet instant, la chaîne pyrotechnique de la fusée 40 se trouve alignée avec le cordeau pyrotechnique 20 et les opérations de mise à feu des différents éléments peuvent se dérouler normalement. Sur la figure 5, le bouclier 6 est représenté en pointillés après le coulissement de la tringle 24. Il n'y a donc plus d'obstacle à la transmission de l'ordre de mise à feu lorsque la chaîne pyrotechnique est initiée.

The reservoir B is linked, for example, by screwing to the warhead A. Its structure is made, for example, of aluminum alloy and it comprises means of dislocation, for example thinned parts as shown in FIG. 2 which shows a cross section AA 'of Figure 1. These thinned parts (29) facilitating the dislocation of the reservoir when is exerted inside the latter a pressure generated, for example, by a charge of powder placed in the reservoir. The reservoir B shown in FIG. 1 comprises:

• an internal beam 8, for example, of aluminum alloy of determined length having, for example, the shape of a quarter of a circular tube; this beam receives rings 9, for example, screwed into wells 30 to allow the ammunition to be hooked under an aircraft. bearing plates 31, for example, made of steel, reinforcing the tank in line with the attachment under the aircraft. They are intended to support the efforts during the carrying. At the point of attachment, two safety cables come out, a safety cable that can be released from the SLO warhead and a safety cable that can be released from the SLC base, enabling the firing rocket to be activated on the one hand. SLO and on the other hand, the locking of the parachute to the structure of the tank as well as the triggering of the delay of the command to release the parachute with regard to the SLC. Each of these safety cables is only operational during the release of the munition. Indeed, after hanging ammunition under aircraft, the traction of each of the cables (SLO, SLC) cannot trigger the implementation of the various steps mentioned above because each of these cables is provided with a safety device positioned at the place where these cables exit so as to prohibit any movement of these. This safety device is provided, for example, with a pallet 32 held in the closed position before hooking under aircraft by a safety pin 11 and a ball not shown in this FIG. 1 positioned on each of the cables so as to be able to strike the pallet when an action is exerted on one of the cables and thus therefore drive it in order to release the movement of the cable. When the ammunition is positioned under the aircraft, the safety pin 11 is removed, the pallet can therefore tilt under the action of the ball fixed on the cable but its movement is blocked by the pylon of the aircraft on which s 'immobilizes the pallet; the cable travel is not sufficient to trigger one of the abovementioned operations and its action is only effective during the release of the ammunition, when traction is exerted on the cable. The two safety cables SLO and SLC slide respectively in channels 10 and 12 to retractor devices 5 and 26 located in the warhead A and the constriction of the base C;
• a filling orifice 13 adapted to the aircraft refueling means in service in NATO;
• reinforcement frames 14, some of which serve as draft shields;
• an automatic level 15 making it possible to stop filling;
• a depressurization valve 16;
• a pump 17 with discharge pipe 18 which can be actuated from the outside, for example, by an electric motor, intended to ensure the agitation of the mixture (hydrocarbon + gelling liquid) to allow homogenization of the components thanks to the vortices generated by the outlet turbulide. Indeed, the electric motor gives the pump a flow and a speed creating a helical vortex which facilitates the mixture of the hydrocarbon and the gelling product. The use of such a pump, on the other hand, facilitates the handling of the ammunition before it is hooked under the aircraft by allowing the loading of the hydrocarbon after fixing the ammunition under the aircraft by obtaining a mixture of such good quality. that a mixture produced before its insertion into the tank of the ammunition;
• a pyrotechnic rod 19 which crosses the tank from one end to the other on its axis of symmetry XX '. It receives on the one hand a pyrotechnic cord 20 allowing the ignition of the propellant loaves 21 and 22 placed at the front and at the rear of the ammunition and illustrated in FIG. 3 which represents a cross section BB ′ of the figure 1 ; these propellant bars 21 generate the internal pressure which ensures the dislocation of the reservoir; the mass and location of these breads are optimized so as to obtain an opening in petals (greater mass at the front than at the rear); these loaves 21 are placed, for example, circularly inside an envelope 33 in connection with the pyrotechnic cord 20 consisting of three elements through the holes 34 inside the pyrotechnic rod 19 allowing the transmission of the firing orders to the various propellant bars, and on the other hand to the gel ignition capsules 23 shown in FIG. 4 which illustrates a cross section CC ′ in FIG. 1; these ignition capsules 23 are ignited by the pyrotechnic cord and are expelled from the pyrotechnic rod 19 on which they were fixed, for example by screwing; the ignition capsules 23 have guide means, for example, fins 35 shown in dotted lines in FIG. 4; they also contain combustion elements 36 ignited by the pyrotechnic cord and whose combustion time, of a few seconds, makes it possible to ignite the mixture during the formation of the cloud, during the fall of the particles and after spreading on the ground, if necessary. The number, size and location of these 23 capsules are defined to obtain a perfect ignition of the spilled mixture after dislocation of the tank. These capsules are made, for example, of light alloy. Inside the pyrotechnic rod 19 and as shown in Figures 1, 2, 3, 4 and 5 is located a rod 24 at the rear of which is attached a parachute 27; this rod 24 is connected, at the front, to the erasure control of the shield 6 which interrupts the pyrotechnic firing chain and which prevents the pyrotechnic cord 20 from being ignited. The rod 24 is immobilized in the pyrotechnic rod 19 by a shear pin 39 which prohibits any movement of the shield 6 to which it is connected by a lever 37 before a traction exerted on the rod 24 after the deployment of the parachute 27; this traction allows the rod 24 to slide inside the pyrotechnic rod 19 and triggers the pivoting of the shield 6 around a point 38. At this instant, the pyrotechnic chain of the rocket 40 is aligned with the pyrotechnic cord 20 and the firing of the different elements can take place normally. In FIG. 5, the shield 6 is shown in dotted lines after the sliding of the rod 24. There is therefore no longer any obstacle to the transmission of the firing order when the pyrotechnic chain is initiated.

• . un empennage fixe (25) fixé sur la structure du réservoir B et est constitué par exemple de quatre ailes dont l'envergure correspond aux diagonales du carré exinscrit au corps du réservoir ;
• . un parachute 27 contenu dans une coupelle 41 lié à la structure du réservoir B par un dispositif de verrouillage et de libération 28 du parachute qui est initialisé par une traction suffisante sur la sécurité largable du culot SLC ;
• . un dispositif rétracteur de la SLC 26 qui permet, après cisaillement de la goupille assurant le maintien de la SLC à l'aéronef grâce à un effort de traction suffisant, de ravaler toute partie de la SLC dépassant l'extérieur de la munition et pouvant gêner le bon déroulement des opérations.

The shrinkage of base C comprises:

• . a fixed stabilizer (25) fixed on the structure of the tank B and consists for example of four wings whose span corresponds to the diagonals of the square exinscribed to the body of the tank;
• . a parachute 27 contained in a cup 41 linked to the structure of the reservoir B by a locking and releasing device 28 of the parachute which is initialized by sufficient traction on the releasable safety of the SLC base;
• . a retractor of the SLC 26 which allows, after shearing of the pin ensuring the maintenance of the SLC to the aircraft thanks to a sufficient traction force, to swallow any part of the SLC beyond the outside of the ammunition and which may hinder the smooth running of operations.

The assembly of these different main parts is carried out in a simple manner, for example, by screwing, to allow during special checks, the inspection and the possible replacement of certain elements.

After describing the ammunition, we will now explain how it works. After taking care to fill the ammunition with the mixture before or after hanging the ammunition as described above and after hanging the latter under the aircraft, it suffices to hang the rings of the SLO releasable safety cables and SLC to the corresponding devices of the aircraft and to remove the safety pins 11 so that the ammunition is ready to operate. When the munition is dropped, the presence paddles 32 pivot and the cables of the SLO and SLC are pulled. The ammunition separates from the aircraft. The SLO unlocks the turbo generator and the rotating rocket support. The rotation of the latter makes it possible to obtain an independent proximity of the roll of the tank. The turbo-generator feeds the proximeter which does not yet detect the ground. The distance device coupled to the turbo alternator begins to rotate the chain misalignment barrel. The SLC authorizes during this time the locking of the parachute to the structure of the ammunition and triggers the delay of the command to release the parachute. At the end of the delay, the deployment of the parachute is ordered; it allows the ammunition to be braked away from the aircraft. When the effort provided by the parachute is sufficient, it pulls the rod 24. The latter shears its pin 39 and slides in the pyrotechnic rod and, having it, moves the shield 6 which interrupted the pyrotechnic chain at the exit of the rocket. A few seconds after the release, the removal device completes the movement of the rocket barrel and aligns the pyrotechnic chain. At a few meters in height, for example, the proximeter detects the ground and triggers initiation of the pyrotechnic chain. The pyrotechnic ignition transmission cord burns inside the pyrotechnic rod and, after a few milliseconds, ignites the propellant bars and the gel ignition capsules. The pressure generated by the propellant bars dislocates the ammunition. The mixture is subjected to aerodynamic pressure which disperses it into droplets. The ignited ignition capsules are expelled into this cloud and continue their trajectory to the ground and burn again for several seconds. The droplets of the mixture are continuously ignited during the fall and after spreading on the ground. If by chance the proximeter were to fail, a backup device, incorporated into the rocket, controls the operation of the pyrotechnic chain at impact on the ground.

When the SLO and SLC safety devices are released without traction, the rocket is not activated, the pyrotechnic chain is misaligned (barrel) and interrupted (shield). On the other hand, the parachute is not locked to the structure and its release is not ordered.

Claims (12)

1. A round of ammunition comprising, arranged along a longitudinal axis XX', a front part A and a rear part C secured to a central position B constituting a reservoir, said central part including an exterior enclosure, said reservoir being designed to be filled with a mixture, which is able to be scattered after breaking up of the enclosure, said round of ammunition including means adapted to produce an action on the mixture, said round of ammunition being characterized in that the mixture is an incendiary mixture and in that the means adapted to produce an action on the mixture are constituted by a pyrotechnic string (20) arranged longitudinally in the reservoir along the axis XX' and by firing capsules (23) arranged in a radial fashion around the string (20) at different longitudinal sites along the string.
2. The round of ammunition as claimed in claim 1, characterized in that the holding of the means for acting on the mixture along the axis XX' is ensured by a pyrotechnic stick (19), said stick having an internal part and an external part and transverse holes (34) between these two parts, the string being arranged in the interior of the stick and the firing capsules (23) being radially secured around the stick in a fashion centered on the transverse holes (34).
3. The round of ammunition as claimed in claim 1 or in claim 2, characterized in that the same comprises propergol charges (21, 22) arranged in front of and behind the reservoir (B).
4. The round of ammunition as claimed in claim 1, characterized in that the same comprises propergol charges (21, 22) arranged in front of and behind the reservoir, said charges (21, 22) being mounted circularly around the pyrotechnic stick (19) in enclosures (33) at sites where they may receive, through the transverse holes (34), a detonation wave coming from the pyrotechnic string 20.
5. The round of ammunition as claimed in any one of the claims 1 through 4, characterized in that the same comprises or double safety means, in the form of a first and a second safety means, preventing firing of the ammunition.
6. The round of ammunition as claimed in claim 5, characterized in that the first safety means comprises a screw (4) locked with the front part (A) in rotation and driving an alternator supplying electrical firing power, a retractor device (5) having two positions, that is to say a first one in which it mechanically prevents the screw from rotating and a second one in which the screw is able to rotate, a cable (SLO) having two ends, that is to say a first and a second end, the first end being secured to the retractor device (5) and the second one leading out of the round of ammunition.
7. The round of ammunition as claimed in claim 6, characterized in that the second safety means comprises a shield (6) arranged between the exit of a detonator (3) and the pyrotechnic string 20, the shield (6) being capable of assuming two positions, that is to say a first position in which it interrupts the pyrotechnic link constituted by the detonator (3) and the string (20) and a second position in which the link is not interrupted, the movement from the first position to the second position being provided by the unfolding of a parachute (27) arranged in the rear part C of the round of ammunition exerting a tensile force on tie (24) secured to the shield (6).
8. The round of ammunition as claimed in claim 7, characterized in that the sliding of the tie (24) is permitted by the severing of a pin (39) under the action of the unfolding of the parachute.
9. The round of ammunition as claimed in claim 1, characterized in that the firing capsules (23) are constituted by tubes provided with small fins in order to increase the stability thereof.
10. The round of ammunition as claimed in claim 1 adapted to be linked to an aircraft, characterized in that a pump (17) is positioned in the interior of the reservoir (B) in such a manner that it produces the mixture when the hydrocarbon is added after the linking of the round of ammunition underneath the aircraft.
11. The round of ammunition as claimed in claim 10, characterized in that the pump (17) is activated by an electric motor arranged outside the round of ammunition in order to permit homogenizing the mixture.
12. The round of ammunition as claimed in claim 1, characterized in that the enclosure of the central part (B) comprises longitudinal flutes (29).

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