EP0457657A1 - Penetrating projectile - Google Patents

Abstract

The purpose of the invention is to provide a new type of penetrating projectiles for the purpose of improving their penetrating power and of controlling the latter better, in particular by providing a solution to the problems related to obliqueness. <??>A projectile according to the invention comprises a front element (1) forming the active part, integral with a tube (2). The tube (2) is closed at the rear of the element (1) and contains a charge (30) for propelling the latter, and an igniter (31) for the said charge, reacting to the percussion of the element (1) against a target. <??>On reaching the target, the projectile penetrates slightly under the effect of speed, and it is only at this time, or slightly later, that the actual penetration occurs, hence without obliqueness. <??>Use as individual munition or as submunition. <IMAGE>

Description

The present invention relates to projectiles, such as arrows, intended to penetrate more or less deeply into a target. It also relates to ammunition containing a plurality of these projectiles, intended for example to be carried in vectors such as missiles, rockets, etc.

European patent application No. 88110917.7 in the name of Diehl GMBH & Co discloses ammunition of this type, intended more specifically for the neutralization of traffic lanes or concrete tracks. It includes a set of arrows contained in a box equipped with a parachute and a propellant. After dropping from a transport vector, there is first opening of the parachute, then once the verticality of the box is correct, starting the thruster. Then, once all the propellant charge has been consumed, a second charge is ignited to expel the arrows from the housing, in order to provide them with additional speed relative to the latter.

The principle implemented in this previous invention is therefore, as in the other currently known penetrating projectile systems, to print a high speed at the arrows in the direction of the target to obtain good penetration, possibly limited by radial projections in the back of the arrows.

However, the expulsion by cannon effect of a bundle of projectiles at high relative speed generally results in large unshocked obliquities at short range, very detrimental to penetration. In addition, as the obliquity is very variable because it also depends very much on the wind, it is almost not possible to predict a precise penetration depth, or to obtain that it is uniform, in particular because of the nutation movement of the projectiles, the direction of which is obviously random at the time of impact. In the neutralization by arrows of relatively tender targets such as taxi-ways or roads, we risk seeing a large part of the arrows sink too deeply, without leaving a protruding part.

On the other hand, the principle of expelling a plurality of projectiles from the same ammunition at high speed has another drawback due to the fact that these ammunition are generally dropped at low altitude. This leads to a concentration of the impacts of the arrows of the same ammunition (a few decimeters), therefore to a distribution in "bouquets" of non-uniform density. This characteristic leads to a significant loss of efficiency, in particular when targeting targets other than runways or communication routes.

The object of the present invention is therefore to provide a new type of penetrating projectiles to overcome these drawbacks, in order to extend their field of use, while increasing their effectiveness.

To this end, the subject of the invention is a penetrating projectile comprising a front element forming the active part intended for penetration, integral with a tube, which tube is closed behind the front element and contains a charge of propulsion thereof, and an igniter for igniting the charge, responding to the percussion of the front element against a target, said projectile further comprising a parachute attached to the rear end of the tube, intended to decrease the speed of said projectile and to bring its longitudinal axis closer to the vertical, characterized in that the igniter comprises a delay means such as the setting propellant charge fire occurs when the speed of the projectile becomes substantially zero.

• la Fig. 1 est une vue en coupe axiale d'un projectile selon l'invention,
• la Fig. 2 est une vue illustrant schématiquement le fonctionnement du projectile de la Fig. 1, par sa représentation à plusieurs instants successifs,
• la Fig. 3 est une vue en coupe axiale d'un autre projectile selon l'invention, prévu pour être contenu en nombre dans une munition,
• la Fig. 4 est une vue en coupe axiale de cette munition, et
• la Fig. 5 est une vue en coupe transversale, selon la ligne V-V de la Fig. 4.

The invention will be better understood using the explanations which follow and the attached drawings, in which:

• Fig. 1 is an axial section view of a projectile according to the invention,
• Fig. 2 is a view schematically illustrating the operation of the projectile of FIG. 1, by its representation at several successive instants,
• Fig. 3 is a view in axial section of another projectile according to the invention, intended to be contained in number in a munition,
• Fig. 4 is an axial section view of this munition, and
• Fig. 5 is a cross-sectional view along the line VV of FIG. 4.

In these figures, the same references have been used to designate the same elements everywhere.

The projectiles according to the invention comprise a front element 1 forming the active part, partially engaged in a rear part or tube 2. At least one intermediate part 10 of the element 1 is cylindrical and of the same caliber as the mouth of the tube 2, which has behind this cylindrical part 10 a retaining shoulder 20. At the front of the part 10, the element 1 has a section which decreases so as to present a front part 11 in the shape of a point clearly protruding from the outlet of the tube 2 .

Inside the tube 2, between the shoulder 20 and its closed rear end, there is successively a chamber 21 containing a propellant charge 30 and, communicating with the chamber 21, a housing 22 for an igniter 31 of the charge 30 The igniter 31 is provided to ensure the ignition of the charge 30 in response to the meeting of the front element 1 with a target, with a delay. In practice, it is preferably an inertial percussion igniter, provided with a delay means for very slightly differing (by a few milliseconds for example) the firing of the charge 30 with respect to the instant of the impact. This delay is provided to allow the speed of the projectile to cancel, or substantially cancel, before the firing of the charge 30; it thus frees the projectile from the penetration constraints due to the non-zero tangential component of its speed relative to the target. This obliquity phenomenon, characterized by the angle of the velocity vector of the projectile and the axis of the shock, in this case the vertical, is one of the major reasons for the non-penetration of the projectile into the target.

Element 1 has certain peculiarities of form which vary according to the application for which the projectile is intended. In the embodiments shown in the drawings, the element 1 is an arrow for the neutralization of tracks or communication paths: it must only sink partially so as to allow a pointed or sharp part to protrude from the ground. 12. To limit the depth of penetration, the size of part 10 of element 1 is significantly greater than that of front part 11. This results in braking by part 10 and, when stationary, partial depression from it, from which follows another advantage, namely that in part 10, the arrow 1 is more difficult to cut. Furthermore, in order to prohibit or, at least, to make it more difficult to extract the arrow by tearing, there is advantageously provided a notch 110 of the front part 11, of the type of that of mountaineer's pitons.

If the element 1 must sink completely into a target, in the case where it is a mine, for example, the terminal tip portion 12 and the notch 110 in the front portion are then superfluous. As for the difference in sizes between parts 10 and 11, although reduced, it will generally be maintained so that the depth of penetration is not too great.

Fig. 2 illustrates the general principle of operation of the projectiles according to the invention, although the particular embodiment of FIG. 1. At time T1, the projectile P arrives close to the target with a certain obliquity, and suitably oriented by means such as tailplane or, as here, parachute. Its speed is not very high, but due to a good mass / section ratio to promote penetration, when the element 1 touches the target, its tip 11 penetrates however a shallow depth, practically reaching the stop at l 'instant T2. At the instant T3 following a few milliseconds the instant T2 (delay of the percussion igniter 31), the charge 30 is ignited, generating a thrust which propels the element 1 more deeply with, in reaction, the expulsion of the tube 2 away from the element 1. This procedure makes it possible to overcome the obliquity at impact and, consequently, to much better control the penetration of the element 1. Note also that for projectiles intended to sink completely into the target, such as mines with a seismic detonator, the discretion necessary for this type of ammunition is not called into question using the principle of the invention, since the tube 2, although remaining apparent, is significantly distant from the projectile itself during the insertion.

An additional advantage of the system is the incendiary power of projectiles when they enter flammable material tanks (planes in the parking lot, fuel tanks, missiles, ammunition, etc.): when the rear tube 2 is ejected, hot and pressurized gases escape at high speed, accompanying the projectile in its progression. This effect can be enhanced by suitable incendiary additives in the propellant charge 30.

The projectile P according to the invention of FIG. 1 is intended to be ejected individually or in bundles from a transport vector. Upon ejection, it therefore has an autonomous behavior, and it is therefore provided with a means to ensure its correct orientation relative to the target. This means consists of a parachute 4 housed in a retractable box 5 fixed to the rear of the tube 2.

The projectile P ′ of FIG. 3 is designed to form with other identical projectiles the active part of the munition M shown in FIGS. 4 and 5. It differs from the version in FIG. 2 in that, instead of a parachute, it has a deploying tail unit formed by several fins 6 at the rear.

Ammunition M essentially comprises a container 7 in which are held side by side several projectiles P ′ pointed towards the exit, a parachute 8 connected by a swivel 9 to the bottom of the container 7 opposite to the exit, and a chronometric sequencer to trigger the release projectiles after a predetermined time after dropping, calculated sufficient for the munition M to reach an attitude close to the vertical and a certain speed (of the order of 40 m / s). The projectiles leave the container 7 by gravity, therefore without significant relative speed, by opening the container 7 or erasing a mechanical restraint. From the exit, the tail of the projectiles P ′ is deployed, for example by a spring means 60 kept loaded inside the container 7.

For the purpose of distributing the projectiles, the container 7 includes means, not shown, for rotating on itself, for example aerodynamic means such as deploying fins. If the rotational speed is 10 revolutions / second at the time of the opening of the container 7, the tangential speed of the projectiles is close to 1.5 m / s, assuming their center of gravity about 24 mm from the axis. For an altitude of 40 m, and an axial speed which, as we recall, is around 40 m / s, we can hope for a distribution on the ground within a circle of diameter: $$\text{2 X 1.5 / 40 X 40 = 3 m}$$

With current munitions where the expulsion speed is much higher, at least 200 m / s, the same rotational speed of 10 revolutions / second and the same altitude of 40 m lead to a dispersion diameter which is not than 0.6 m. However, we know that with these known munitions, the obliquity already poses a problem and that it would not be wise to make it even more important by increasing the rotational speed. Consequently, compared with known systems, the munition of the invention provides a considerably improved distribution of the projectiles P ′.

In practice, ammunition such as the ammunition M of Figs. 4 and 5 are perfectly suited to equip large cargo ships provided with sophisticated ejection devices allowing controlled dispersion adapted to the target, while the individual projectile version illustrated in FIG. 1 is more suitable for small freighters handling smaller areas.

Of course, the invention is not limited to the examples described above, and it can be adapted, for example, to improve existing weapon systems. In one of these systems, a carrier projectile, of rocket type, contains sub-projectiles in the form of arrows arranged with a single orientation (the head forward and the tail back of the rocket). Propulsion means ensure the ejection of the sub-projectiles along the trajectory of the rocket, after its warhead has itself been expelled. An important drawback of these munitions is that their practical range is limited by the terminal kinetic energy necessary for the correct penetration of the sub-projectiles. Thus, at distances of around 2,000 m, the impact velocities are of the order of 700 m / s, while above 4,000 m, they drop below 300 m / s. The kinetic energies vary in a ratio of the order of 5, and much more if one seeks an even higher range. The use of tailed sub-projectiles in accordance with the invention to equip these rockets is a solution for increasing the range or even increasing the penetration.

Claims (9)

1) penetrating projectile comprising a front element (1) forming the active part intended for penetration, integral with a tube (2), which tube (2) is closed behind the front element (1) and contains a charge (30) for propelling the latter, and an igniter (31) for igniting the charge (30), responding to the percussion of the front element (1) against a target, said projectile comprising by elsewhere a parachute attached to the rear end of the tube (2) intended to reduce the speed of said projectile and to bring its longitudinal axis closer to the vertical, characterized in that the igniter (31) comprises a delay means such as the setting the propellant charge (30) is ignited when the speed of the projectile becomes substantially zero. 2) Projectile according to claim 1, characterized in that the front element (1) comprises a front part (11) in the shape of a point, provided with a non-deformable part (10) of larger section to limit penetration and prevent destruction of the front element (1). 3) Projectile according to claim 1 or 2, characterized in that the charge (30) comprises incendiary additives. 4) Projectile according to one of claims 1 to 3, characterized in that the front element (1) is a mine. 5) Projectile according to one of claims 1 to 3, characterized in that the front element (1) is an arrow. 6) Projectile according to one of claims 1 to 5, characterized in that the rear part (12) of the element (1) is pointed or sharp. 7) Projectile according to claim 5 or 6, characterized in that the front part (11) of the element (1) comprises an anti-tearing notch. 8) Projectile according to one of claims 1 to 7, characterized in that the tube (2) comprises a tail (6), for use as a submunition. 9) Ammunition intended to be released from a transport vector, comprising as submunitions projectiles (P ′) according to claim 8, retained side by side in a housing (7) provided with a parachute ( 8), characterized in that it comprises means for ensuring the release by gravity, therefore without initial speed, of the projectiles (P ′) when predetermined conditions of slope with respect to the vertical and of speed of the housing (7) are together, the latter further comprising means for rotating on itself to distribute the submunitions (P ′).

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