FR2842897A1 - MULTI-PUSH CALIBER PROJECTILE - Google Patents

Abstract

The technical sector of the invention is that of subcaliber projectiles (1) comprising a caliber sabot (2) formed of at least two segments and surrounding a subcaliber bar (4). This projectile is characterized in that the sabot (2) comprises at least three bearing surfaces (6.12; PP; 9.11) substantially to the caliber, axially spaced from one another.

Description

The technical field of the invention is that of projectiles under

  calibrated comprising a caliber shoe formed by at least two segments and surrounding an under-calibrated bar. Such projectiles are well known and are usually called arrow projectiles because the rod is

stabilized by a tail.

  The hoof usually has a push plate at the

  caliber on which a sealing belt is mounted.

  The shoe also has another bearing support for the caliber making it possible to complete the guiding of the projectile in the tube by preventing the tilting of the axis of the bar by

relative to the axis of the tube.

  This other bearing surface can be located in front of the guide plate as described below with reference to the

  Figure 1 (shoe said "pulled-pushed").

  It can also be located behind the guide plate as described below with reference to Figure 2

(shoe said to be "towed").

  We are now seeking to produce arrow projectiles having improved performance both from the point of view of

  speed of the bar as its perforation capacities.

  The increase in speed can be obtained by an increase in the mass of the propellant charge, which leads to the design of projectiles in which the plate

  thrust is arranged far forward.

  The hoof thrust plate is therefore inserted into the barrel of the weapon well before the rear support reach stabilizes the hoof. There is then in the first moments of the interior ballistics phase a risk of pivoting of the projectile around the hinge formed by the belt. Such pivoting leads to poor angular positioning of the projectile in the tube which can lead to oscillations disturbing the stability

of the bar robbery.

  Work on improving performance has also led to the design of projectiles incorporating a very long bar, the rear part of which penetrates

  deep into the propellant charge.

  The shoe must then be reinforced at its rear part to ensure the drive of the inertia of the

  bar, which is detrimental to the lightness of the hoof.

  In addition, an elongated bar causes bending oscillations of the rear part of the projectile in the barrel of the weapon which also leads to a disturbance of the

stability of the projectile flight.

  It is the object of the invention to propose a projectile

  not having such drawbacks.

  Thus the projectile according to the invention comprises a shoe of reduced mass but nevertheless ensuring improved guidance of the projectile in the tube making it possible to avoid obliquities

  positioning as well as the vibrations of the bar.

  Thus the subject of the invention is a sub-calibrated projectile comprising a sabot with a caliber formed by at least two segments and surrounding a sub-calibrated bar, projectile characterized in that the sabot comprises at least three bearing surfaces substantially at caliber, spaced apart axially from each other. The distance between the two most distant staves

  will preferably be greater than or equal to 3 calibers.

  According to a particular embodiment, at least one bearing surface, called median bearing surface, is constituted by a push plate comprising at least one groove receiving a belt, push plate which is located

  axially between two other bearing surfaces.

  Advantageously, the thrust plate will be disposed at a distance from a median transverse plane PM, plane orthogonal to the rod and passing through the center of gravity of the complete projectile, distance which will be between 0.5 and 1.5

calibers.

  A front bearing surface may be constituted by radial arms regularly distributed angularly around the shoe. Each arm may carry at its end a plastic pad ensuring the guide of the shoe in the tube. A rear bearing surface may be constituted by radial studs, regularly distributed angularly around the shoe. Each radial stud may be integral with a segment of the

shoe.

  Alternatively, each radial stud may be formed by the juxtaposition of two parts, each integral with a

distinct segment of the hoof.

  Each radial stud may carry at its end a shoe made of friction-resistant material, for example steel, ensuring the guiding of the shoe in the tube. The invention will be better understood on reading the

  description which follows of particular modes of

  realization, description made with reference to the drawings

  attached and in which: - Figures 1 and 2 show in longitudinal section two projectiles according to the prior art placed in the barrel of a weapon, - Figures 3a and 3b show in longitudinal section a projectile according to a first mode of embodiment of the invention, FIG. 3a shows the projectile placed in position and FIG. 3b the projectile inside the tube during firing, - FIGS. 4a and 4b show in longitudinal section a projectile according to a second embodiment of the invention, FIG. 4a shows the projectile placed on station and FIG. 4b the projectile inside the tube during firing, FIGS. 5a and 5b show in cross section two alternative embodiments of the rear bearing surfaces, - FIGS. 6a and 6b show in partial longitudinal and transverse sections an embodiment of a rear support surface, - FIGS. 7a and 7b show in partial longitudinal and transverse sections another m ode of realization

a rear support span.

  Figures 1 and 2 show two arrow projectiles

according to the prior art.

  The projectile 1 shown in FIG. 1 is a conventional projectile comprising a shoe 2 formed by three

  sectors surrounding a bar 4 carrying a tail 5.

  The shoe 2 has a front bearing surface 6 which has the shape of a bowl having a substantially circular rim

to the diameter of the barrel 7 of the weapon.

  The shoe 2 also includes a rear bearing surface which forms a push plate PP to which the

propellant gas pressure.

  This PP push plate has a groove receiving

  a belt 8 ensuring gas tightness.

  This shoe 2 is of the “pulled-pushed” type, which means that the push plate PP is located axially substantially at or slightly behind a median transverse plane PM which is the plane orthogonal to the bar 4 and passing

  by the center of gravity of the complete projectile.

  We see that when this projectile is placed in the barrel of the weapon the two bearing surfaces are in contact with the tube. However the length of bar 4 which is still in the chamber 10 of the weapon is important. Bending oscillations of the rear part of the bar will occur during the firing which will disturb the stability of the bar flight. The solutions implemented to date lead to reinforcing the rigidity of the rear part of the hoof by increasing the thickness of the hoof which weighs down

this one.

  The projectile 1 shown in Figure 2 has a similar general structure and also includes a shoe 2 formed of three segments surrounding a bar 4. It differs from the previous in that its front bearing surface is constituted by the push plate PP , while the rear bearing surface is constituted by three radial studs 9 integral with the shoe 2 and substantially of caliber. Such a shoe is of the "towed" type. Indeed, the thrust plate PP carrying the belt 8 is here axially very in front of the median transverse plane PM, orthogonal to the bar

  4 and passing through the center of gravity of the complete projectile.

  We see that when this projectile is placed in the barrel of the weapon (as shown in Figure 2), the rear bearing surface is in the chamber. It can only provide its guiding function when the projectile has penetrated further into the barrel of the weapon. This results in a

  risk of the projectile pivoting around the belt 8.

  In both cases the guide length l, which is the distance between the two ranges, is of the order of 1.5 calibers for the towed hoof projectile according to FIG. 2 and 2.5 calibers for the towed hoof projectile. driven

of figure 1.

  A first embodiment of a projectile 1 according to

  the invention is shown in Figures 3a and 3b.

  This projectile is a projectile with a "towed-pushed" shoe, like the one according to FIG. 1. It differs from the latter in that shoe 2 has three bearing surfaces substantially of caliber and which are axially spaced apart.

each other.

  The projectile thus comprises -a front bearing surface 6 which has the shape of a bowl having a circular rim substantially at the diameter of the tube 7 of the weapon, -a median bearing surface which is constituted by the thrust plate PP carrying the belt 8, -a rear support bearing constituted by radial studs ll regularly distributed angularly around the

shoe 2.

  It results from such a configuration that when the projectile 1 is inside the tube 7 (Figure 3b) the bar is held relative to the tube by three

guide surfaces (6, PP and 11).

  This avoids oscillations of the rear part of the bar even for long bars (upper

30 times their diameter).

  The guide length L, that is to say the distance between the two most distant ranges (6 and 11) is greater than or equal to 3 calibers, ie substantially double the

  anterior guide bearing 1 (figure 1).

  The rear studs 11 have a mass which is much less than the shoe mass which would have been necessary in the rear part to prevent the bar from oscillating. The projectile according to the invention therefore has improved rigidity

while having a reduced mass.

  In order to avoid deterioration of the rear studs 11 during the passage of the forcing cone, each stud 11 will be provided

  a pad 14 made of resistant material, for example steel.

  A second embodiment of a projectile 1 according to

  invention is shown in Figures 4a and 4b.

  This projectile is a "towed" shoe projectile like that according to Figure 2. It differs from the latter in that shoe 2 has three bearing surfaces substantially at

  caliber and which are axially spaced from each other.

  The projectile thus comprises: -a rear bearing surface constituted by radial studs 9 regularly distributed angularly around the shoe 2, -a middle bearing surface which is constituted by the thrust plate PP carrying the belt 8, -a bearing front support which is constituted by radial arms 12 regularly distributed angularly around the

shoe 2.

  Each arm 12 carries at its end a shoe 13 made of plastic which ensures the guide of the shoe in the tube 7. Again, it follows from this configuration that when the projectile 1 is inside the tube 7 (Figure 4b) the bar is held relative to the tube by three

guide surfaces (9, PP and 12).

  This avoids oscillations of the rear part of the bar even for long bars (upper

30 times their diameter).

  The guide length L, i.e. the distance between the two most distant spans (9 and 12) is greater

or equal to 3 calibers.

  In addition, the presence of the arms 12 forming the front guide surface makes it possible to prevent the projectile from tilting.

  when it is posted (Figure 4a).

  The distance L1 between the front 12 and middle PP reaches

  is thus greater than or equal to 1.5 calibers.

  The mass of the arms 12 is reduced and does not excessively weigh down the hoof. The projectile according to the invention has

  therefore improved rigidity while having a reduced mass.

  Furthermore, the thrust plate PP of this shoe is placed at a distance from the median transverse plane PM (plane orthogonal to the rod and passing through the center of gravity of the complete projectile) which is between 0.5 and

1.5 calibers.

  Such an arrangement makes it possible to optimize the mass of the hoof. Thus the thrust plate PP of the projectile is advanced relative to the forcing cone 16 of the weapon when

the ammunition is stationed.

  We can verify by calculation that the optimal mass gain for a 120mm caliber shoe is obtained by advancing the thrust plate by about 80mm compared to its usual position at the forcing cone 16. This results in lightening of the shoe from 15 to 20% for a cost of

analogous manufacturing.

  It will be possible to give the arms 12 a front profile forming a pocket receiving the aerodynamic flow at the outlet of the barrel of the weapon. Such an arrangement makes it possible to facilitate the separation of the sabot segments at the outlet from the barrel of the weapon. In order to avoid deterioration of the rear studs 9 during the passage of the forcing cone 16, each stud 9 will be provided

  a pad 14 made of resistant material, for example steel.

  Figures 5a and 5b show in cross section two alternative embodiments of the rear bearing surfaces 9 or 11. Each radial stud 9 or 11 forming the rear bearing can thus be integral with a single segment 2a, 2b or 2c of the shoe

  2 as shown in Figure 5a.

  Each radial stud 9 or 11 may on the contrary be formed by the juxtaposition of two parts, each integral with a distinct segment of the shoe 2a, 2b or 2c, as shown in the

Figure 5b.

  Each rear radial stud 9 or 11 will preferably have a pad 14 made of a resistant material, for example in

  steel, which will guide the shoe in the tube.

  FIGS. 6a and 6b thus show rear studs 9 or 11 provided with pads 14 made in the form of screws

  introduced into threads carried by studs 9 or 11.

  Figures 7a and 7b show rear pads 9 or 11 with pads 14 which are all made in the form of plates, with a tip 15 having a dovetail shape and cooperating with a form groove

  complementary fitted at the end of stud 9 or 11.

  It is of course possible to design a projectile comprising more than three bearing surfaces. It is also possible to design a projectile comprising three bearing surfaces and in which the thrust plate carrying the belt constitutes the most forward range or else the

rearmost reach.

Claims (6)

  1- Projectile (1) under calibrated comprising a shoe (2) with the caliber formed by at least two segments and surrounding a bar (4) under calibrated, projectile characterized in that the shoe comprises at least three bearing surfaces (6 , 12; PP; 9,11) substantially to size, axially spaced from each other. 2- Projectile according to claim 1, characterized in that the distance between the two most distant ranges   (6.12; 9.11) is greater than or equal to 3 calibers.   3- Projectile according to one of claims 1 or 2,   characterized in that at least one bearing surface, called median bearing surface, is constituted by a push plate (PP) comprising at least one groove receiving a belt (8), push plate which is located axially between two others bearing surfaces.   4- Projectile according to claim 3, characterized in that the thrust plate (PP) is disposed at a distance from a median transverse plane (PM), plane orthogonal to the rod and passing through the center of gravity of the complete projectile,   distance which is between 0.5 and 1.5 calibers.   - Projectile according to one of claims 3 or 4,   characterized in that a front bearing surface is formed by regularly distributed radial arms (12) angularly around the hoof (2).   6- Projectile according to claim 5, characterized in that each arm (12) carries at its end a pad (13) in   plastic material guiding the shoe in the tube.   7- Projectile according to one of claims 1 to 6,   characterized in that a rear bearing surface is formed by radial studs (9,11) regularly   distributed angularly around the hoof.   8- Projectile according to claim 7, characterized in that each radial stud (9,11) is integral with a segment of the shoe. 9- Projectile according to claim 7, characterized in that each radial stud (9,11) is formed by the juxtaposition of two parts each secured to a separate segment of the shoe. 10- Projectile according to claim 9, characterized in that each radial stud (9,11) carries at its end a shoe (14) of friction-resistant material, for example steel, ensuring the guidance of the shoe in the tube