EP0130885B1 - Practice ammunition and flechette projectile - Google Patents

Abstract

1. A practice projectile consisting of a sabot which can be discarded after the gun phase and a sub-projectile (1) of the armour piercing, the projectile being constituted by a front penetrator body (7) fitted with a ballistic ogive (9) and outlet ports (12), and a rear penetrator body (6) possibly fitted with an aerodynamic tail unit (8), the front and rear bodies being interconnected by an elastic coupling (11) and actuated after a predetermined flight path, characterized in that it include a self-contained compressed gas holder (3) co-operating with a perforating striker (4) in order to generate a gas expansion inside an enclosure (2) housed in the front and rear bodies, the striker (4) and the gas holder (3) being located on both sides of the elastic coupling (11) and of the ports (12) which are closed by the interposition of either the striker (4) or the gas holder (3) during the perforation of the membrane (5) and then free when the striker (4) or the gas holder (3) returns to its original position.

Description

The technical sector of the present invention is that of artillery projectiles, and more particularly under calibrated projectiles of arrow type for exercise.

Exercise projectiles have been known for a long time, constituted by a sabot eliminable after the cannon phase and by a sub-projectile of the arrow type, the sub-projectile having to be destabilized so as to modify its ballistic behavior to reduce its trajectory.

Patent FR-A-2 39 703 describes an exercise projectile of the hoof-type eliminable according to the preamble of claims 1, 7, 9, 11 and which has a trajectory and a stroke duration identical to those of a shock cone projectile of comparable type, but which must fall on the ground as quickly as possible beyond the distance of exercise. The sub-projectile consists of two parts, the assembly means of which are actuated by the firing of the projectile and maintained under a pressure originating from the ignition gases, therefore from an external source during the predetermined trajectory. This system gives poor reproducibility, because the phenomena involved are difficult to control since the means of assembling the different parts of the sub-projectile are dependent on the combustion gases, in particular unburnt materials which can frequently interfere with the operation of the mechanisms.

GB-A-2 089 946 also describes an arrow-type exercise projectile comprising separable elements. But the connection of the elements is disintegrated using special pyrotechnic means arranged in the vicinity of this connection. This technique therefore involves a particular architecture of the sub-calibrated projectile and the interposition of a specific pyrotechnic module to eject the ballistic cap beyond a certain distance.

In a neighboring technical sector, that of stabilized projectiles in rotation such as shells, it has also been proposed to destabilize these projectiles by modifying their gyroscopic stability.

Thus, US-A-4,241,660 proposes the interposition of a fluid in a cavity of the projectile. This fluid under the effect of the rotational movement alters the moment of inertia of the projectile causing its destabilization. Alternatively, it is proposed to pass this fluid contained in a first cavity to a second cavity using the pressure of a compressed gas.

Patent DE-A-2 744 790 also describes a self-propelled, rotationally stabilized shell, consisting of two parts, one internal with respect to the other. The destabilization is carried out by translation of one of the parts, which causes a change in configuration and aerodynamic braking.

This braking system gives the projectiles a safety gauge that is too important for small maneuvering grounds.

The present invention aims to obtain, while avoiding the aforementioned drawbacks, a destabilization of a sub-projectile beyond the firing distance imposed by simple technical means which are easy to implement with constant reproducibility.

The subject of the invention is therefore an exercise projectile constituted by a sabot eliminable after the cannon phase and by a sub-projectile of the arrow type, the projectile consisting of a front arrow body provided with a ballistic warhead and of 'flow holes, and a rear boom body optionally provided with a tail, the front and rear bodies being joined by an elastic coupling and actuated after a predetermined path, characterized in that it comprises an autonomous reservoir of compressed gas cooperating with a puncturing striker to generate an expansion of the gas inside an enclosure internal to the front and rear bodies, the striker and the reservoir being situated on either side of the elastic coupling and of the orifices ices which are locked by the interposition either of the striker or of the reservoir during the perforation of the membrane then released when the striker or the reservoir return to their original position.

The striker is coaxial with the reservoir obstructed by a membrane so as to perforate this membrane during the gun phase.

The reservoir is fixed in the enclosure at the rear body and the striker, integral with the front body, is mobile under the action of forces due to longitudinal acceleration.

The reservoir is disposed at the front of the enclosure at the front body and is movable under the action of forces due to longitudinal acceleration, the striker being fixed and integral with the rear body.

The striker is connected to the front jib body by a bar having a breaking point and provided with a needle, the gas expansion chamber being delimited on the longitudinal axis by the autonomous tank and the striker and on the periphery by the two bodies of arrows.

• - dans sa position initiale est maintenu par la barrette;
• - dans une première position intermédiaire, libéré par inertie pendant sa phase canon, poinconne la membranne obstruant le réservoir autonome,
• - dans une deuxième position intermédiaire, est déplacé vers l'avant du sous-projectile par la détente du gaz, la pression dans l'enceinte maintenant l'accouplement élastique entre les deux parties du sous-projectile,
• - revenu à sa position initiale, libère les orifices permettant l'écoulement du gaz suivant une loi prédéterminée pour la libération de l'accouplement élastique entre les deux parties du sousprojectile en vue de sa déstabilisation.

In the enclosure and successively, the striker:

• - in its initial position is maintained by the bar;
• - in a first intermediate position, released by inertia during its gun phase, punches the membrane obstructing the autonomous reservoir,
• - in a second intermediate position, is moved towards the front of the sub-projectile by the expansion of the gas, the pressure in the enclosure maintaining the elastic coupling between the two parts of the sub-projectile,
• - returned to its initial position, frees the orifices allowing the gas to flow according to a predetermined law for the release of the elastic coupling between the two parts of the subprojectile for its destabilization.

The invention also relates to an exercise projectile constituted by a sabot eliminable after the cannon phase and by a sub-projectile of the arrow type, the projectile consisting of a body of arrow provided at the front with a ballistic warhead, and at the rear of a tailplane, characterized in that the sub-projectile comprises an autonomous reservoir of compressed gas cooperating with a puncturing striker to generate an expansion of the gas inside an enclosure internal to the body and a probe secured to the body of the sub-projectile by a calibrated pin, the striker being connected to the sub-projectile by a calibrated pin, the enclosure for the expansion of the gas being delimited on the periphery by the sub-projectile and on the longitudinal axis by the reservoir and the striker provided with circular calibrated longitudinal orifices allowing the enclosure to communicate with an enclosure delimited on the periphery by the sub-projectile and on the longitudinal axis by the striker and the rear face probe era.

• - dans sa position initiale est maintenu par la goupille,
• - dans une première position intermédiaire, libéré par inertie pendant la phase canon, poinçonne la membrane obstruant le réservoir autonome,
• - dans une deuxième position intermédiaire, est déplacé vers l'avant du sous-projectile par la détente du gaz,
• - revient à sa position initiale, le gaz s'écoulant à travers les orif ices suivant une loi d'écoulement prédéterminée dans l'enceinte en exerçant un effort déterminé sur la face de la sonde pour le déplacement de cette dernière vers l'avant du sous-projectile jusqu' à une butée constituée par la face arrière de l'ogive en vue de la déstabilisation du sous-projectile.

In the enclosure and successively, the striker:

• - in its initial position is maintained by the pin,
• - in a first intermediate position, released by inertia during the gun phase, punches the membrane obstructing the autonomous tank,
• - in a second intermediate position, is moved towards the front of the sub-projectile by the expansion of the gas,
• - returns to its initial position, the gas flowing through the orifices according to a predetermined flow law in the enclosure by exerting a determined force on the face of the probe for the displacement of the latter towards the front of the sub-projectile up to a stop constituted by the rear face of the warhead for the destabilization of the sub-projectile.

The invention also relates to an exercise projectile constituted by a sabot eliminable after the cannon phase and by a sub-projectile of the arrow type, the projectile consisting of a front arrow body provided with a ballistic warhead and a rear jib body possibly fitted with a tail, the front and rear bodies being joined by a coupling actuated after a predetermined trajectory, characterized in that it comprises an autonomous reservoir of compressed gas cooperating with a perforating striker to generate a detent gas inside an enclosure internal to the front and rear bodies, the striker and the reservoir being located on either side of the coupling, the two arrow bodies being locked together during the barrel phase at the hoof as well as by a calibrated shear pin and unlocked to separate at the end of a predetermined trajectory for the destabilization of the sub-projectile.

• - dans sa position initiale est maintenu par un joint élastique,
• - dans sa position intermédiaire, libéré par inertie pendant la phase canon, est projeté sur le percuteur qui poinçonne la membrane obstruant ce réservoir,
• - revient à la position initiale, le gaz libéré exerçant un effort sur la goupille qui se rompt, pour la séparation des deux parties du sous- projectile, en vue de sa déstabilisation.

In the enclosure and successively, the tank:

• - in its initial position is maintained by an elastic seal,
• - in its intermediate position, released by inertia during the gun phase, is projected onto the striker which punches the membrane obstructing this reservoir,
• - Returns to the initial position, the released gas exerting a force on the pin which breaks, for the separation of the two parts of the sub-projectile, with a view to its destabilization.

The invention also relates to an exercise projectile constituted by a sabot eliminable after the cannon phase and by a sub-projectile of the arrow type, the projectile consisting of a body of arrow provided at the front with a ballistic warhead, and at the rear of a tail, characterized in that the sub-projectile comprises an autonomous reservoir of compressed gas cooperating with a puncturing striker to generate an expansion of the gas inside an enclosure internal to the body, the striker being connected to the sub-projectile by a bar comprising a rupture initiator and provided with a needle, the enclosure for the expansion of the gas being delimited on the longitudinal axis by the autonomous tank and the striker and on the periphery by the sub-projectile, calibrated circular orifices being provided at the front of the sub-projectile between the striker and the reservoir and masked by the striker or the reservoir during the perforation of the membrane and released when the striker or the reservoir ir returns to its original position, allowing the enclosure to communicate with a variable volume enclosure arranged on the external wall of the sub-projectile.

• - dans sa position initiale est maintenu par la barrette,
• - dans une première position intermédiaire, libéré par inertie pendant la phase canon, poinçonne la membrane obstruant le réservoir autonome,
• - dans une deuxième position intermédiaire, est déplacé vers l'avant du sous-projectile par la détente du gaz,
• - revenu à sa position initiale, libère les orifices, permettant l'écoulement du gaz suivant une loi prédéterminée dans l'enceinte pour une modification de forme du sous-projectile en tête à un moment prédéterminé de la trajectoire en vue de la déstabilisation du sous-projectile.

In the enclosure and successively the striker:

• - in its initial position is maintained by the bar,
• - in a first intermediate position, released by inertia during the gun phase, punches the membrane obstructing the autonomous tank,
• - in a second intermediate position, is moved towards the front of the sub-projectile by the expansion of the gas,
• - returned to its initial position, frees the orifices, allowing the gas to flow according to a predetermined law in the enclosure for a modification of the shape of the sub-projectile at the head at a predetermined moment of the trajectory with a view to the destabilization of the sub -projectile.

• - la figure 1 montre le projectile au repos, en coupe longitudinale, d'après le premier mode de réalisation selon la première variante, c'est-à-dire le percuteur étant mobile et le réservoir fixe,
• - la figure 2 montre le projectile au repos, en coupe longitudinale, c'est-à-dire le percuteur étant fixe et le réservoir mobile selon la seconde variante,
• - la figure 3 montre le sous-projectile pendant la phase canon selon la première variante,
• - la figure 4 montre le sous-projectile en début de trajectoire selon la première variante,
• - la figure 5 montre l'accouplement élastique entre les deux parties du sous-projectile selon la coupe A-A de la figure 1,
• - la figure 6 est une coupe transversale selon la coupe B-B de la figure 1,
• - la figure 7 montre un deuxième mode de réalisation selon la première variante des moyens permettant la destabilisation du sous-projectile,
• - la figure 6 montre un troisième mode de réalisation des moyens de destabilisation, selon la deuxième variante,
• - la figure 9 montre un troisième mode de réalisation des moyens de destabilisation selon la première variante,
• - la figure 10 montre un quatrième mode de réalisation des moyens de destabilisation, selon la première variante,
• - la figure 11 montre le quatrième mode de réalisation des moyens de destabilisation, selon la seconde variante.

The invention will be illustrated with the aid of the detailed description which follows of various variants given by way of nonlimiting examples, with reference to the drawing in which:

• FIG. 1 shows the projectile at rest, in longitudinal section, according to the first embodiment according to the first variant, that is to say the striker being mobile and the reservoir fixed,
• FIG. 2 shows the projectile at rest, in longitudinal section, that is to say the striker being fixed and the tank movable according to the second variant,
• FIG. 3 shows the sub-projectile during the cannon phase according to the first variant,
• FIG. 4 shows the sub-projectile at the start of the trajectory according to the first variant,
• FIG. 5 shows the elastic coupling between the two parts of the sub-projectile according to section AA of FIG. 1,
• FIG. 6 is a cross section along section BB of FIG. 1,
• FIG. 7 shows a second embodiment according to the first variant of the means allowing the destabilization of the sub-projectile,
• FIG. 6 shows a third embodiment of the destabilization means, according to the second variant,
• FIG. 9 shows a third embodiment of the destabilization means according to the first variant,
• FIG. 10 shows a fourth embodiment of the destabilization means, according to the first variant,
• - Figure 11 shows the fourth embodiment of the destabilization means, according to the second variant.

At rest, before the start of the shot, the projectile, according to the first embodiment according to the first variant, is shown in Figure 1. The striker (4) is in its initial position, held by the bar. The two parts (6) and (7) of the sub-projectile (1) are held together by the shoe, until the end of the cannon phase, no pressure in the enclosure (2) still acting on the elastic coupling (11).

During the barrel phase, the striker (4) is released by the rupture initiator which the bar comprises and therefore mobile in the cavity (2), in such a way that, under the effect of the longitudinal forces acting on it, it activates the pressure source by punching the membrane (5) obstructing the autonomous tank (3) (see Figure 3).

The gas contained under pressure in the tank (3) then expands in the enclosure (2), this having the first consequence of pushing back the striker (4) towards the front of the sub-projectile (1), then as a second consequence of locking the elastic coupling (11) between the two parts (6) and (7) of the sub-projectile (1).

At the start of the trajectory, the striker (4) returned to its original position, the projectile (1) finding itself in the same configuration as that of FIG. 1, the sabot having been eliminated after the gun phase. Returning to its original position, the striker (4) releases the orifices (12) provided in the front part (7) of the sub-projectile (1), thus allowing the gas contained under pressure in the enclosure (2) and now locked the elastic coupling (11) between the two parts (6) and (7) of the sub-projectile (1), to flow through the orifices (12) according to a predetermined flow law. The pressure then gradually decreases in the enclosure (2) and the unlocking of the elements (6) and (7) begins thanks, on the one hand, to the residual pressure remaining in the enclosure (2), and on the other hand part unlike the forces due to the aerodynamic drag of each of the two elements (6) and (7) (see fig. 4). Thus the two parts (6) and (7) of the sub-projectile (1) separate to ensure the destabilization of the sub-projectile (1) on its trajectory. In the first embodiment according to the second variant, shown in Figure 2, the striker (4) is fixed and is an integral part of the rear part (6) of the sub-projectile (1). In this embodiment, it is the reservoir (3) which is released during the barrel phase by a rupture initiator and therefore mobile in the cavity (2) so that, under the effect of the longitudinal forces acting on it, it is projected onto the striker (4) thus punching the membrane (5). The gas contained under pressure in the tank (3) then expands in the enclosure (2), thus pushing the tank (3) towards the front of the sub-projectile (1). Destabilization then occurs in an identical manner to that of the main embodiment.

FIG. 7 represents a second embodiment according to the first variant.

The sub-projectile (1) comprises a probe (13) secured to the body of the sub-projectile (1) by a calibrated pin (14) which breaks at a determined force. This principle still allows the use of an autonomous reservoir (3) of a pressurized gas which, after release, destabilizes the sub-projectile (1) thanks to the probe (13) at a defined distance. At rest, before the start of the shot, the sub-projectile (1) is presented according to FIG. 7. The striker (4) is held in its initial position by a calibrated pin (15) which breaks during the gun phase, under the effect of the inertia of the striker (4), thus releasing it in the enclosure (2) delimited on the periphery by the sub-projectile (7) and on the longitudinal axis by the reservoir (3) and the striker (4) provided with circular calibrated longitudinal orifices (12) allowing the enclosure (2) to communicate with an enclosure (16) delimited, on the periphery by the sub-projectile (1) and on the longitudinal axis by the striker (4) and the face (17) of the probe (13).

The striker (4), under the effect of the forces acting on it, activates the pressure source by perforating the membrane (5) obstructing the autonomous reservoir (3), then rises towards the front of the sub-projectile (1) under the effect of the expansion of the gas in the enclosure (2) to its original position. The gas thus contained in the enclosure (2) flows through the orifices (12) according to a predetermined flow law to settle in the enclosure (16) by exerting a determined force on the face (17 ) of the probe (13) so as to break the calibrated pin (14), a seal (19) being provided so as to avoid any drop in pressure between the enclosure (16) and the front of the sub- projectile (1). The overpressure in the enclosure (2) causes the probe (13) to move forward as far as a stop constituted by the rear face of the warhead secured to the sub-projectile (1), to create the instability of the sub-projectile (1) by a significant reduction in the static margin.

It is also possible to produce this first variant according to the second embodiment, that is to say the striker (4) being fixed at the rear of the sub-projectile (1) and the reservoir (3) movable at the inside the enclosure (2), the overpressure causing a probe located at the rear of the sub-projectile to move.

FIG. 8 represents a third embodiment according to the first variant.

The sub-projectile (1) consists firstly of a rear arrow body (6) receiving the tail (8) and the part of the enclosure (2) formed by the striker (4) forming an integral part of the sub-projectile (1), and secondly by a front arrow body (7) provided with the ballistic warhead (9) and the part of the enclosure (2) containing the reservoir (3). At rest (fig. 8), the reservoir (3) is held in its initial position by an elastic seal. Then under the effect of the longitudinal forces the reservoir (3) is released by inertia in the enclosure (2) so as to be projected onto the striker (4), thus punching the membrane (5) obstructing the autonomous reservoir (3) . The reservoir (4) then returns to the initial position, the gas thus released exerting a force on the calibrated shear pin (14) which breaks under the effect of this force as well as under the effect of the force due to the difference in aerodynamic drag of the elements (6) and (7) of the sub-projectile (1) with a view to its destabilization.

This third embodiment can also be produced according to the first variant (fig. 9), that is to say the reservoir (3) being fixed at the rear of the sub-projectile (1) and the striker (4) movable inside the enclosure (2), the overpressure causing the pin (14) to break for the separation of the two parts (6) and (7) of the sub-projectile (1) with a view to its destabilization.

FIG. 10 represents a fourth embodiment according to the first variant.

The sub-projectile (1) is in a single part and comprises a variable volume enclosure (18) arranged on its external wall.

During the canon phase, the operation is identical to that of the first embodiment.

At the start of the trajectory, once the striker (4) returns to its original position and the orifices (12) released, the gas contained under pressure in the enclosure (2) flows according to a predetermined law in the enclosure variable volume (18) until equilibrium is established between the variable volume enclosure (18) and the enclosure (2) for a change in shape of the sub-projectile (1) at the head at a time precise trajectory for the destabilization of the sub-projectile (1).

Finally, this fourth embodiment can be produced according to the second variant, the striker (4) being fixed at the rear of the sub-projectile (1) and the tank (3) movable inside the enclosure (2) (see fig. 11).

It therefore follows from the foregoing that the sub-projectile (1) of the exercise shoe type of the removable shoe described in the invention separates into at least two parts (6) and (7) which fall to the ground by being quickly braked due to increased air resistance.

Sub-projectiles consisting of more than two parts can of course be used.

Finally, the invention relates to all training munitions comprising such a projectile.

Claims (12)

1. A practice projectile consisting of a sabot which can be discarded after the gun phase and a sub-projectile (1) of the armour piercing, the projectile being constituted by a front penetrator body (7) fitted with a ballistic ogive (9) and outlet ports (12), and a rear penetrator body (6) possibly fitted with an aerodynamic tail unit (8), the front and rear bodies being interconnected by an elastic coupling (11) and actuated after a predetermined flight path, characterized in that it include a self-contained compressed gas holder (3) co-operating with a perforating striker (4) in order to generate a gas expansion inside an enclosure (2) housed in the front and rear bodies, the striker (4) and the gas holder (3) being located on both sides of the elastic coupling (11) and of the ports (12) which are closed by the interposition of either the striker (4) or the gas holder (3) during the perforation of the membrane (5) and then free when the striker (4) or the gas holder (3) returns to its original position.

2. A practice projectile as claimed in Claim 1, characterized in that the striker (4) is coaxial with the gas holder (3) obturated by a membrane (5) so as to perforate this membrane (5) during the gun phase.

3. A practice projectile as claimed in Claim 2, characterized in that the gas holder (3) is attached inside the enclosure (2) at the location of the rear body (6) and in that the striker (4) integral with the front body (7) can be set in motion by the longitudinal acceleration forces.

4. A practice projectile as claimed in Claim 2, characterized in that the gas holder (3) is located in the front part of the enclosure (2) at the location of the front body (7) and can be set in motion by the longitudinal acceleration forces, the striker (4) being fixed and integral with the rear body (6).

5. A practice projectile as claimed in any one of Claims 2 or 3, characterized in that the striker (4) in linked with the front penetrator body (7) by a connector bar which has a starting point of fracture and fitted with a needle (10), the gas expansion enclosure (2) being delimited along the longitudinal axis by the self-contained gas holder (3) and the striker (4) and on the periphery by the two penetrator bodies (6) and (7).

6. A practice projectile as claimed in Claim 5, characterized in that in the enclosure (2) and successively, the striker (4) :

- in its initial position is secured by the connector bar;

- in a first intermediate position, released by inertia during its gun phase, punches the membrane (5) obstructing the self-contained gas holder (3);

- in a second intermediate position, is moved to the front of the sub-projectile (1) by the gas expansion, the pressure in the enclosure (2) keeping the elastic coupling (11) between the two parts (6) and (7) of the sub-projectile (1);

- having returned to its initial position, frees the ports (12), thus allowing the gas to flow according to a pre-determined law in order to release the elastic coupling (11) between the two parts (6) and (7) of the sub-projectile (1) with a view to destabilizing it.

7. A practice projectile, consisting of a sabot which can be discarded after the gun phase and a sub-projectile (1)

the projectile being constituted by a penetrator body fitted in its front part with a ballistic ogive (9) and in its rear part with an aerodynamic tail unit (8), characterized in that the sub-projectile (1) includes a self-contained compressed gas holder (3) cooperating with the perforating striker (4) in order to generate a gas expansion inside an enclosure (2) housed in the body and a probe (13) integral with the body of the sub-projectile (1) via a calibrated pin (14), the striker (4) being linked with the sub-projectile (1) by a calibrated pin (15), the gas expansion enclosure (2) being delimited on the periphery by the sub-projectile (1) and along the longitudinal axis by the gas holder (3) and the striker (4) fitted with calibrated longitudinal circular ports (12) allowing the enclosure (2) to communicate with an enclosure (16) delimited on the periphery by the sub-projectile (1) and along the longitudinal axis by the striker (4) and the rear face (17) of the probe (13).

8. A practice projectile as claimed in Claim 7, characterized in that in the enclosure (2) and successively, the striker (4) :

- in its initial position is secured by the pin (15);

- in a first intermediate position, released by inertia during the gun phase, punches the membrane (5) obstructing the self-contained gas holder (3) ;

-in a second intermediate position is moved to the front of the sub-projectile (1) by the gas expansion ;

- returns to its initial position, the gas flowing through the ports (12) according to a predetermined law in the enclosure (16) while exerting a determined effort on the face (17) of the probe (13) so as to move the latter towards the front of the sub-projectile (1) up to a stop constituted by the rear face of the ogive (9) with a view to destabilizing the sub-projectile (1).

9. A practice projectile consisting of a sabot which can be discarded after the gun phase and a sub-projectile (1)

the projectile being constituted by a front penetrator body (7) fitted with a ballistic ogive (9) and a rear penetrator body (6) possibly fitted with an aerodynamic tail unit (8), the front and rear bodies being interconnected by a coupling (14) actuated after a predetermined flight path, characterized in that it includes a selfcontained compressed gas holder (3) co-operating with a perforating striker (4) in order to generate a gas expansion inside an enclosure (2) housed in the front and rear bodies, the striker (4) and the gas holder (3) being located on both sides of the coupling (14), the two penetrator bodies (6) and (7) being locked together during the gun phase by means of the sabot and by a calibrated shear pin (14) and unlocked so as to separate at the end of a pre-determined flight path with a view to destabilizing the sub-projectile (1).

10. A practice projectile as claimed in Claim 9, characterized in that in the enclosure (2) and successively, the gas holder (3) :

- in its initial position is secured by an elastic joint;

- in its intermediate position, released by inertia during the gun phase, is thrown on to the striker (4) which punches the membrane (5) obstructing the gas holder;

- returns to its initial position, the released gas exerting an effort on the pin (14) which breaks, for the separation of the two parts (6) and (7) of the sub-projectile (1), with a view to destabilizing it.

11. A practice projectile consisting of a sabot which can be discarded after the gun phase and a sub-projectile (1)

the projectile being constituted by a penetrator body fitted in its front part with a ballistic ogive (9) and in its rear part with an aerodynamic tail unit (8), characterized in that the sub-projectile (1) includes a self-contained compressed gas holder (3) co-operating with a perforating striker (4) for generating a gas expansion inside an enclosure (2) housed in the body, the striker (4) being linked with the sub-projectile (1) by means of a connector bar which has a starting point of fracture and fitted with a needle (10), the gas expansion enclosure (2) being delimited along the longitudinal axis by the self-contained gas holder (3) and the striker (4) and on the periphery by the sub-projectile (1), calibrated circular ports (12) being provided in the front part of the sub-projectile (1) between the striker and the gas holder and masked by the striker (4) or the gas holder (3) during the perforation of the membrane (5) and freed when the striker or the gas holder returns to its original position, thus allowing the enclosure (2) to communicate with a variable-volume enclosure (18) located on the external wall of the sub-projectile (1).

12. A practice projectile as claimed in Claim 11, characterized in that in the enclosure (2) and successively, the striker (4) :

- in its initial position is secured by the connector bar ;

- in a first intermediate position, released by inertia during the gun phase, punches the membrane (5) obstructing the self-contained gas holder (3);

- in a second intermediate position is moved towards the front of the sub-projectile (1) by the gas expansion;

- having returned to its initial position, frees the ports (12), thus allowing the gas to flow according to a predetermined law in the enclosure (18) for changing the shape of the sub-projectile (1) on top of the flight path at a predetermined time with a view to destabilizing the sub-projectile (1).

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