EP0478452A1 - Electromagnetic gain with rails - Google Patents

Abstract

The field of the invention is that of electromagnetic projectile launchers and more particularly that of electromagnetic guns with rails. According to the invention, an electromagnetic gun with rails for a projectile (P) comprising an electrically conducting casing (A) comprises a succession of supply units (B1...BK) for electrically supplying a succession of segments (S1...SK) of a projectile launching path formed by two parallel rails, the said segments (S1...SK) being insulated from each other on at least one of the said rails and each of the said supply units (B1...BK) being connected to the rear of one of the said path segments (S1...SK) by two terminals (BA, BB) in order to supply a propulsive current to the said projectile when the latter penetrates into the corresponding path segment (SK), the supply unit (B1...BK) of the said corresponding path segment (S1...SK) applying to the said path segment (S1...SK) of path, before the penetration of the said projectile (P) in the said path segment (S1...SK), a voltage less than a critical voltage at which appears a risk of formation of a parasitic arc between the rails of the said path segment (S1...SK), the propulsive current being provided by the supply unit (BK) owing to the presence of the said casing (A) of the said projectile (P) between the rails of the said corresponding rail segment (SK). The invention applies to the military field in particular. <IMAGE>

Description

The field of the invention is that of electromagnetic projectile launchers and more precisely that of electromagnetic rail guns.

It has been proposed to launch a projectile using an electromagnetic gun comprising a launching path formed by two parallel rails. The projectile is guided by these rails via a movable frame which is electrically conductive. A very high current, which can be called "propulsive current", passes through these rails and this armature and applies a propulsive force of an electromagnetic nature to the latter. It is supplied by a succession of power supplies which electrically supply a corresponding succession of segments of the launching track.

• Une érosion des rails apparaît. Elle est directement liée à l'intensité du courant. Elle est donc maximale à l'extrémité arrière de la voie, c'est-à-dire à celle d'introduction du projectile, surtout si ce dernier est introduit à vitesse nulle.
• Le projectile pouvant éventuellement être équipé d'un système de guidage destiné à accroître son efficacité en phase d'approche finale, il ne peut alors supporter des accélérations supérieures à 100 000 G.
• Quand le stockage d'énergie dans les blocs d'alimentation se fait sous forme électrostatique, c'est-à-dire dans des condensateurs de stockage, chacun de ces derniers se comporte comme une source de tension à impédance interne quasi nulle. Les courants instantanés de décharge peuvent alors atteindre des valeurs telles que les 100 000 G soient largement dépassés et que l'érosion des rails devienne inacceptable. Il faut donc associer aux condensateurs des inductances de régularisation dont le rôle est de limiter les intensités de court-circuit, et allonger le temps de décharge pour le rendre compatible avec la longueur du canon, elle-même dépendante de la vitesse souhaitée pour le projectile et de l'astreinte imposée à l'accélération. Un problème posé par l'association condensateur-inductance est alors que cette association constitue un circuit oscillant et que, au moment où l'intensité du courant atteint sa valeur maximale, la tension aux bornes du condensateur s'annule puis s'inverse. Or, les condensateurs à forte densité d'énergie sont de type électrolytique et l'application d'une tension inverse est préjudiciable à leur durée de vie. C'est pourquoi dans un canon connu, un dispositif interrupteur à fermeture ultra rapide dit "Commutateur Crowbar" est monté en parallèle avec le condensateur pour assurer sa protection et permettre d'utiliser, pour la propulsion du projectile, l'énergie qui a été accumulée dans l'inductance.

The realization of such a cannon poses various problems:

• Rail erosion appears. It is directly related to the intensity of the current. It is therefore maximum at the rear end of the path, that is to say that of introduction of the projectile, especially if the latter is introduced at zero speed.
• The projectile possibly being able to be equipped with a guidance system intended to increase its efficiency during the final approach phase, it cannot then support accelerations greater than 100,000 G.
• When energy storage in power supplies is done in electrostatic form, that is to say in storage capacitors, each of these behaves like a voltage source with almost zero internal impedance. The instantaneous discharge currents can then reach values such that the 100,000 G are largely exceeded and that the erosion of the rails becomes unacceptable. It is therefore necessary to associate with the capacitors regularization inductors whose role is to limit the short-circuit intensities, and extend the discharge time to make it compatible with the length of the barrel, itself dependent on the desired speed for the projectile and the penalty imposed on acceleration. A problem posed by the capacitor-inductance association is then that this association constitutes a oscillating circuit and that, when the current intensity reaches its maximum value, the voltage across the capacitor is canceled out and then reversed. However, capacitors with a high energy density are of the electrolytic type and the application of a reverse voltage is detrimental to their lifespan. This is why in a known gun, an ultra-fast closing switch device called "Crowbar switch" is mounted in parallel with the capacitor to ensure its protection and allow the energy which has been used to propel the projectile. accumulated in the inductance.

• Limitation du courant d'appel du fait de l'établissement instantané d'une force contre-électromotrice, fonction de la vitesse de déplacement.
• Suppression du phénomène d'érosion localisée qui est produit par le courant, à son intensité maximale, pour la formation du plasma et la mise en mouvement du projectile.

Various solutions have been considered to solve these problems:
A limitation of the erosion of the rails is obtained if an initial speed is communicated to the projectile and to the associated reinforcement before their introduction on the launching track. This initial speed has the following effects:

• Limitation of the inrush current due to the instantaneous establishment of a counter-electromotive force, function of the speed of movement.
• Suppression of the localized erosion phenomenon which is produced by the current, at its maximum intensity, for the formation of the plasma and the setting in motion of the projectile.

Different types of "pre-launchers" can be envisaged, such as, for example, a conventional chemical launcher or a light gas cannon.

An improvement in the transfer of energy from power supplies to the projectile has been proposed and is based on the facility, inherent in capacitive storage, to distribute the energy necessary for a shot between several groups of capacitors. Such a configuration makes it possible to significantly reduce the electrical resistance of the circuit, by distributing the energy in space and / or in time, depending on whether the segments of the launcher rails are or are not separated by insulating intervals.

The absence of such intervals, however, requires having ultra-fast switches synchronized with the passage of the projectile at the right of the different segments, which is not necessary for the solution with separate segments. However, in a case like in the other, it is necessary to have capacitor protection switches against reverse polarity, (Crowbar switches), as indicated above.

In general, the feeding of the rail guns proposed, with separate segments or not, seemed to have to resort to expensive switching devices with very rapid opening and / or closing.

An electromagnetic gun with rails comprising such switching devices is for example described in US Patent No. 4,319,168 in the name of Kemeny. Each of the two rails of the launching ramp described is divided into conductive segments isolated from each other by means of insulation. A sensor, of the electrical, optical or mechanical type, for projectile passage detection, is associated with a segment and controls the opening and closing of a switch at the terminals of which an energy storage capacitor is connected in series with a pulse transformer. Each sensor is placed upstream of the corresponding channel segment to allow the switch to close in a time corresponding to the transit time of the projectile between this sensor and the rear of the corresponding segment to which the pulse is applied.

American Patent No. 4,343,223 to Hawke et al also describes an electromagnetic gun in which the pulses are supplied by successive discharges of capacitors connected all along rails forming a continuous launching ramp or consisting of segments of rails isolated from each other . The capacitors are successively controlled by electronic or optical sensors arranged along the rails controlling switches each connected in series with a capacitor.

The main drawback of this type of projectile launcher is that the switching devices have to be very fast and are therefore expensive. In addition, they must withstand a very high impulse current and the electric arcs caused by the closing of these devices quickly deteriorate their contacts.

It has however been proposed the use of diodes or other semiconductor devices, either to ensure the function switch, or in the role of non-return system. The intensities and voltages to be used for supplying the rail guns lead to series / parallel associations of these components, associations which degrade their performance, in particular dynamic (dI / dt, dV / dt, I²dt).

Another disadvantage of launchers whose generation of pulses is controlled by sensors is that positioning the sensors is difficult to achieve. In particular, the response speed drifts of the sensors and especially of the switches controlled by these sensors are observed, which generates a pulse generation temporally offset, early or late, relative to the moment when the projectile passes between the ends of a segment. There is then no longer optimization of the moment of generation of the pulse and the efficiency of the gun is affected. In addition, when the weight of the charge of the projectile to be launched is changed, it is necessary to reposition the position sensors to optimize the instants of generation of the pulses since a heavy projectile will be late compared to a lighter projectile.

The present invention aims in particular to overcome these drawbacks.

• Régulariser l'accélération d'un projectile lancé par un canon électromagnétique à rails.
• Limiter l'usure des rails qui résulte du passage du courant propulsif à travers un plasma formé entre l'armature conductrice de ce projectile et chacun de ces rails.
• Augmenter le rendement du transfert d'énergie entre des condensateurs de stockage et ce projectile.
• Optimiser les instants de génération des impulsions destinées à accélérer le projectile, quelles que soient la masse de ce projectile et la taille du canon.
• Faciliter la réalisation d'un tel canon grâce à l'utilisation de composants connus de coût modéré et de fiabilité prouvée.
• Faciliter la réalisation de tels canons adaptés au lancements de projectiles de types et de vitesses diverses, grâce à la possibilité de réaliser cette adaptation par remplacement de certains seulement des composants de ces canons.

The present invention has in particular the following aims:

• Regularize the acceleration of a projectile launched by an electromagnetic rail gun.
• Limit the wear of the rails which results from the passage of the propellant current through a plasma formed between the conductive armature of this projectile and each of these rails.
• Increase the efficiency of energy transfer between storage capacitors and this projectile.
• Optimize the instants of generation of the pulses intended to accelerate the projectile, whatever the mass of this projectile and the size of the gun.
• Facilitate the production of such a cannon through the use of known components of moderate cost and proven reliability.
• Facilitate the production of such cannons suitable for launching projectiles of various types and speeds, thanks to the possibility to achieve this adaptation by replacing only some of the components of these guns.

These objectives, as well as others which will appear subsequently, are achieved by means of an electromagnetic gun with projectile rails comprising an electrically conductive frame, said gun comprising a succession of power supply units for electrically supplying a succession of segments. a projectile launch path formed by two parallel rails, said segments being isolated from each other on at least one of said rails and each of said power supplies being connected to the rear of one of said track segments by two terminals for delivering a propelling current to said projectile when the latter enters the corresponding track segment, the power supply of said corresponding track segment applying to said track segment, before said projectile penetrates said track segment, a lower voltage at a critical voltage at which there appears a risk of a parasitic arc forming between the rails of said seg track, the propellant current being supplied by the corresponding power supply unit due to the presence of said armature of said projectile between the rails of said corresponding rail segment,

Using the attached schematic figures, we will describe below how the present invention can be implemented, it being understood that the elements and arrangements mentioned and represented are only by way of nonlimiting examples. When the same element is represented in several figures, it is designated therein by the same reference sign.

Figure 1 shows an overview of a gun according to the present invention.

Figure 2 shows a view of a last power supply for this gun.

We will describe in general various preferable arrangements which are adopted in this canon and illustrated by these figures.

The barrel comprises various elements which are analogous, as regards their functions, to elements whose use has already been proposed for make such a canon. Such known elements constitute two guide rails R, S for guiding a projectile P via a projectile armature A. These rails extend in the same longitudinal direction, forming for this projectile a launching path which extends from a rear end 8 to a front end 10. These rails and this frame comprise electrically conductive elements for conducting a propellant current in series in one of these rails then through this frame, then in the other of these rails. A transverse gap between these conductive elements of these two rails constitutes an electrical width D of this launching path. In the cannon given as an example, the same metal part provides both, for each rail, the functions of mechanical guidance and conduction of the electric current. But it should be understood that these two functions could be performed by two separate parts, the whole of which would constitute the rail.

On at least one of these rails one can distinguish a longitudinal succession of rail segments S1 ... SK, so that the launching track can be considered as consisting of a succession of track segments which are defined by these rail segments. These track segments follow one another in increasing rows from a first segment of rank S1 at the rear end of this track, to a last segment SK at its front end.

In the example cannon only one S of the two rails is a "segmented" rail made up of segments which are separated by insulating intervals. However, it should be understood that the present invention can also be applied when the distinction between the successive segments results only from the electrical supply of the rail at successive points and from the electrical resistance of the rail.

A succession of power supplies B1 ... BK correspond to the track segments S1, ... SK. These blocks are controlled during each shot of a projectile to electrically supply the track segments successively as the projectile progresses. Each of them supplies the corresponding track segment by supplying it with propulsive current through two terminals BA, BB. These two bounds belong to this segment. They are respectively connected to the two rails at a rear end of this segment. The passage of this current through these rails creates a magnetic field. This field interacts with the current flowing through the armature A and thus applies a propelling force directed towards it.

• des condensateurs de stockage d'énergie pour stocker, au cours d'une période de charge préalable à chaque tir, l'énergie électrique nécessaire à la propulsion du projectile dans le segment de voie correspondant à ce bloc d'alimentation,
• et une inductance de régularisation connectée en série avec ces condensateurs de stockage entre les bornes du segment de voie correspondant pour régulariser l'intensité du courant propulsif pendant une période de transit du projectile dans ce segment.

Each of the power supplies itself includes:

• energy storage capacitors for storing, during a charge period prior to each shot, the electrical energy necessary for propelling the projectile in the track segment corresponding to this power supply,
• and a regulation inductor connected in series with these storage capacitors between the terminals of the corresponding channel segment to regulate the intensity of the propellant current during a period of transit of the projectile in this segment.

The gun also includes charging means for charging each of these storage capacitors during this charging period. In the cannon given as an example, these charging means consist of a dynamo-electric generator 2 associated with conditioning circuits not shown and with a rapid energizing switch 4 which is closed at the start of each charging period.

It also includes projectile introduction means 6 for introducing the projectile P provided with its armature A at the rear end of the first segment S1. Preferably these means comprise a pre-launcher 6 which can be of known type.

• une borne active W1 connectée à l'une des bornes BA du segment de voie SK correspondant à ce bloc d'alimentation,
• une borne passive X1 connectée à l'autre borne BB de ce segment de voie,
• et une succession d'étages d'alimentation E1...EN. Cette succcession comporte un premier étage E1 et d'autres étages dont chacun, tel que l'étage E2, suit un étage précédent tel que l'étage E1. Chacun de ces étages, par exemple l'étage EN comporte une première borne avant WN d'une première polarité, une deuxième borne avant XN d'une deuxième polarité, une première borne arrière YN de la première polarité et une deuxième borne arrière ZN de la deuxième polarité. Les première et deuxième bornes avant du premier étage constituent respectivement les bornes active W1 et passive X1 de ce bloc d'alimentation. Les première et deuxième bornes avant WN et XN de chaque autre étage d'alimentation tel que l'étage EN sont respectivement connectées aux première et deuxième bornes arrières telle que Y N-1 et Z N-1 de l'étage précédent tel que l'étage EN-1. Chacun de ces étages comporte les éléments suivants qui sont décrits dans le cas de l'étage EN :
• un condensateur de stockage CN connecté entre ses première et deuxième bornes arrières YN et ZN, et une inductance de régularisation LN connectée entre ses premières bornes avant et arrière WN et YN. Les deuxièmes bornes avant et arrière XN et ZN de cet étage sont mutuellement connectées. Il en résulte que les inductances de régularisation de ces étages successifs E1...EN sont connectées en série en formant une succession d'inductances L1...LN qui est connectée à la borne active W1 et que les condensateurs de stockage C1...CN de ces mêmes étages sont connectées entre d'une part la borne passive X1 et d'autre part des bornes successives Y1...YN de cette succession d'inductances, à la manière d'une ligne à retard. Grâce à cette disposition, lorsque les bornes de ce bloc sont connectées l'une à l'autre par l'armature de véhicule A par l'intermédiaire des rails R et S après que lesdits condensateurs de stockage C1...CN aient été chargés, le bloc d'alimentation BK délivre le courant propulsif sous la forme d'une impulsion de décharge qui tend à se rapprocher d'une impulsion rectangulaire, c'est-à-dire qu'elle présente un front de montée et un front de descente séparés par une largeur d'impulsion propre à ce bloc d'alimentation. Cette largeur dépend au moins des capacités des condensateurs de stockage C1...CN, des valeurs des inductances de régularisation L1...LN et du nombre N des étages d'alimentation. Cette largeur d'impulsion et le temps de transit du projectile P dans le segment de voie SK correspondant à ce bloc d'alimentation BK sont mutuellement adaptés. Cette adaptation mutuelle est réalisée idéalement, dans la mesure où l'impulsion de décharge présente des fronts de montée et de descente verticaux, si ces fronts de montée et de descente coïncident respectivement avec les instants d'entrée et de sortie de l'armature A dans le segment de voie correspondant. Dans la pratique cette coïncidence est seulement approximative.

In accordance with the present invention, each power supply unit, for example the last BK unit, comprises:

• an active terminal W1 connected to one of the terminals BA of the track segment SK corresponding to this power supply,
• a passive terminal X1 connected to the other terminal BB of this track segment,
• and a succession of supply stages E1 ... EN. This succession comprises a first stage E1 and other stages each of which, such as stage E2, follows a preceding stage such as stage E1. Each of these stages, for example the stage EN comprises a first terminal before WN of a first polarity, a second terminal before XN of a second polarity, a first rear terminal YN of the first polarity and a second rear terminal ZN of the second polarity. The first and second front terminals of the first stage respectively constitute the active W1 and passive X1 terminals of this power supply. The first and second terminals before WN and XN of each other supply stage such as the stage EN are respectively connected to the first and second rear terminals such as Y N-1 and Z N-1 of the preceding stage such that l 'EN-1 floor. Each of these stages has the following elements which are described in the case of the EN stage:
• a storage capacitor CN connected between its first and second rear terminals YN and ZN, and a regulation inductance LN connected between its first front and rear terminals WN and YN. The second front and rear terminals XN and ZN of this stage are mutually connected. It follows that the regulation inductors of these successive stages E1 ... EN are connected in series by forming a succession of inductances L1 ... LN which is connected to the active terminal W1 and that the storage capacitors C1 .. .CN of these same stages are connected between on the one hand the passive terminal X1 and on the other hand of the successive terminals Y1 ... YN of this succession of inductances, in the manner of a delay line. Thanks to this arrangement, when the terminals of this block are connected to each other by the vehicle frame A via the rails R and S after said storage capacitors C1 ... CN have been charged , the power supply BK delivers the propellant current in the form of a discharge pulse which tends to approach a rectangular pulse, that is to say that it has a rising edge and a descent separated by a pulse width specific to this power supply. This width depends at least on the capacities of the storage capacitors C1 ... CN, the values of the regulation inductors L1 ... LN and the number N of the supply stages. This pulse width and the transit time of the projectile P in the track segment SK corresponding to this power supply BK are mutually adapted. This mutual adaptation is ideally carried out, insofar as the discharge pulse has vertical rising and falling edges, if these fronts rise and fall coincide respectively with the instants of entry and exit of the reinforcement A in the corresponding track segment. In practice this coincidence is only approximate.

The length L of the track segments is limited so that the number K of these segments is greater than three. This number is chosen to pass a propellant current of substantially constant intensity through the projectile armature A.

It is advantageous to increase the number of these segments in particular so that the counter-electromotive force resulting from the movement of the projectile does not exhibit, during the duration of the transit of this projectile in a track segment, too great a variation which would cause the l intensity of the propelling current and therefore of the propelling force. However, each segment should have a sufficient length so that the intensity of the magnetic field at the rear of the frame is generally not significantly reduced. The propulsive force is in fact proportional to the product of this field intensity by the intensity of the propulsive current passing through the armature.

This is why, preferably the length L of each of the track segments S1 is equal to or greater than five times the electrical width D of the launch track.

Preferably the storage capacitors are electrolytic capacitors. Each of these capacitors, for example the capacitor CN, has two electrodes 12, 14 and is protected against reverse polarity by a capacitor protection rectifier DN connected between the first rear terminal YN of its supply stage EN and one of the two electrodes of this capacitor. This electrode constitutes a "protected" electrode 14.

Preferably the charging means 2, 4 charge a said power supply unit such as BK by charging in parallel the storage capacitors C1 ... CN of the successive power supply stages E1 ... EN of this block. Each of these capacitors is charged through a charge protection rectifier GN connected to its protected electrode 14.

In the example cannon, each of the power supplies B1 ... BK is fitted with a load inductace LS1 ... LSK which may or may not be saturable. The charging means 2, 4 charge this block through this charge inductor.

According to an arrangement that is sometimes preferable and adopted in the cannon given as an example at least some of the track segments S1 ... SK and in fact, all of these segments have equal lengths L. In this case, the pulse widths of the blocks B1 ... BK which correspond to these segments decrease when the rank of these segments increases.

According to an alternative arrangement not shown, at least some of the power supplies of the segments B1 ... BK have the same pulse width. The track segments S1 ... SK corresponding to these blocks then have lengths which increase with the rank of these segments.

Of course compromises may be preferable between these two alternative arrangements.

The preceding description shows, taking into account the use of a pre-launcher, that the only switching device used is the power-up switch 4. It can be operated between each shot or only between each shot campaign ( in case of bursts of fire). Load inductors, saturable such as inductors LS1 ... LSK, or unsaturable, can be dimensioned according to the shortest time interval between two shots. The switch 4 can be of any type, manual, electromagnetic control (the case shown in the diagram), or static (in this case, in any case, provide an isolation switch). A preferred model has the particularity of using the through current as assistance in closing.

All of the above provisions make it possible to significantly increase the energy efficiency of the rail launcher and therefore to reduce its consumption of primary energy. It is then possible to make close shots or even burst shots.

The discharge pulses being triggered by the activation contact of the two rails of the same rail segment, an optimization of the instants of triggering of these pulses is obtained, whatever the mass of the projectile. It is then possible to design electromagnetic guns of different lengths and for projectiles of different masses and / or types, without having to adapt the positions of sensors and the response times of switches.

The structure of the power supplies makes it possible to reduce the amount of energy present at the terminals of a rail segment.

In known electromagnetic guns, it appeared necessary, in order to obtain sufficient power from the gun, to charge the storage capacitors under relatively high voltages which, if they were applied permanently between the rails of the gun, would create a risk of formation of a parasitic electric arc. This risk is conventionally avoided by the use of rapid switching devices. It is reduced, according to the invention, by the fact that the charging voltage of the storage capacitors can be reduced without loss of power from the gun, which makes it possible to avoid the use of rapid switching devices for known guns. We can therefore directly connect a power supply to the ends of this segment.

The structure of the power supply units is therefore perfectly suited to establishing a pulse by bringing the rails into contact with the armature of the projectile.

In general, the present invention applies to any power supply unit generating an energy discharge pulse of amplitude less than a critical voltage at which appears a risk of creation of a parasitic arc, this critical voltage being a function the spacing of the barrel rails.

This type of power supply unit corresponds in particular to a duration proportional to that of the transit time of a projectile on a rail segment.

Claims (10)

1 / Electromagnetic gun for projectile rails (P) comprising an electrically conductive frame (A), said gun comprising a succession of power supply units (B1 ... BK) for electrically supplying a succession of segments (S1 .. .SK) of a projectile launching path formed by two parallel rails, said segments (S1 ... SK) being isolated from each other on at least one of said rails and each of said power supply units (B1 ... BK) being connected to the rear of one of said track segments (S1 ... SK) by two terminals (BA, BB) to deliver a propellant current to said projectile when the latter enters the track segment (SK) corresponding, characterized in that the power supply unit (B1 ... BK) of said corresponding track segment (S1 ... SK) applies to said track segment (S1 ... SK) before the penetration of said projectile (P ) on said track segment (S1 ... SK), a voltage below a critical voltage at which there is a risk of forma tion of a parasitic arc between the rails of said semgnet (S1 ... SK) of the track, and in that the propellant current is supplied by the power supply unit (BK) due to the presence of said armature (A) of said projectile (P) between the rails of said segment (SK) of corresponding rail. 2 / electromagnetic gun according to claim 1, characterized in that each of said power supply units (B1 ... BK) is formed by a succession of stages (E1 ... EN) each comprising a storage capacitor (CN) energy and a current regulation inductor (LN), said inductors (L1 ... LN) being connected in series and said capacitors (C1 ... CN) in parallel to form a pulse having a suitable pulse width the duration of the transit of said projectile (P) in said track segment (SK) corresponding to this block. 3 / Canon according to one of claims 1 and 2, comprising: - two guide rails (R, S) for guiding said projectile (P) by means of a projectile armature (A), these rails extending in the same longitudinal direction forming, for this projectile, a channel launch that extends from one end rear (8) at a front end (10), these rails and this armature comprising electrically conductive elements for conducting an electric propulsive current in series in one of these rails then through this armature, then in the other of these rails, a transverse gap between these conductive elements of these two rails constituting an electrical width (D) of said launching track, at least one of these rails forming a longitudinal succession of rail segments, so that said launching track consists of a succession of track segments (S1 ... SK) which are defined by these rail segments and which succeed each other in increasing rows starting from a first segment of row one (S1) at the rear end this way, - And a corresponding succession of segment supply blocks (B1, ... BK), these blocks being controlled during the firing of a said projectile to supply said track segments electrically successively as the progression of this projectile on said launch track, each of these blocks supplying the corresponding track segment by supplying it with said propellant current through two terminals (BA, BB) of this segment which are respectively connected to the two said rails at one end rear of this segment, so as to apply to said projectile armature (A), by electromagnetic interaction, an electromagnetic propelling force directed towards the front, - each of these power supplies itself comprising: - energy storage capacitors for storing, during a charge period prior to each said shot, the electrical energy necessary for propelling said projectile in the track segment corresponding to this power supply, - and a regulation inductor connected in series with said storage capacitors between said terminals of said corresponding channel segment to regularize the intensity of said propellant current during a transit period of said projectile in this segment, - Said gun also comprising means (2, 4) for charging charge each of said storage capacitors during said charging period, - and projectile introduction means (6) for introducing a said projectile (P) provided with a said frame (A) at said rear end of said first segment (S1) before each said shot, said barrel being characterized in that each said segment supply unit (BK) comprises: an active terminal (W1) connected to a said terminal (BA) of a said track segment corresponding to this power supply, - a passive terminal (X1) connected to the other said terminal (BB) of this track segment, - And a succession of supply stages (E1 ... EN), this succession comprising a first stage (E1) and other stages each of which (E2) follows a preceding stage (E1), these stages each comprising ( EN) a first front terminal (WN) of a first polarity, a second front terminal (XN) of a second polarity, a first rear terminal (YN) of said first polarity and a second rear terminal (ZN) of said second polarity, said first and second front terminals of said first stage (E1) respectively constituting said active (W1) and passive (X1) terminals of this power supply, said first (WN) and second (XN) terminals before each said other supply stage (EN) being respectively connected to said first (Y N-1) and second (Z N-1) rear terminals of said previous stage (EN-1), each of these stages comprising a said storage capacitor (CN ) connected between its said first and second rear terminals (YN and ZN), and a said regulation inductor (LN) connected between its said first front and rear terminals (WN and YN), said second front and rear terminals (XN and ZN) of this stage being mutually connected, thanks to what, when said terminals (BA, BB) of this block are connected to each other by said vehicle frame (A) via said rails (R, S) after said storage capacitors (C1. ..CN) have been charged, said power supply unit (BK) delivers said propellant current in the form of a discharge pulse having a rising edge and falling edge separated by a pulse width specific to this power supply, this pulse width and said transit period of said projectile (P) in said track segment (SK) corresponding to this block feed (BK) being mutually adapted. 4 / barrel according to one of claims 1 to 3, characterized in that the number (K) of said track segments (S1 ... SK) is greater than three. 5 / Canon according to one of claims 2 to 4, characterized in that said storage capacitors (C1 ... CN) are electrolytic capacitors, each of these capacitors (CN) having two electrodes (12, 14) and being protected against reverse polarity by a capacitor protection rectifier (DN) connected between said first rear terminal (YN) of its said supply stage (EN) and one of said electrodes of this capacitor, this electrode constituting a protected electrode (14). 6 / Canon according to claim 3, characterized in that said charging means (2, 4) charge a said power supply (BK) by charging in parallel said storage capacitors (C1 ... CN) of said stages d successive supply (E1 ... EN) of this block, each of these capacitors being charged through a charge protection rectifier (GN) connected to its said protected electrode (14). 7 / Canon according to claim 6, characterized in that each of said power supply units (B1 ... BK) is provided with a charge inductor (LS1 ... LSK), said charge means (2, 4 ) charging this block through this charge inductor. 8 / barrel according to one of claims 1 to 7, characterized in that the length of each of said track segments (S1) is equal to or greater than five times said electrical width (D) of said launch track (R, S). 9 / barrel according to one of claims 1 to 8, characterized in that the power supplies are identical and the rail segments of steadily increasing length. 10 / Canon according to one of claims 1 to 9, characterized in that the power supplies although made up of identical sub-assemblies are designed to store the energy necessary to supply sections of rail of constant length .

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