FR2512540A1 - EXERCISE AMMUNITION FOR CANON - Google Patents

Abstract

THE INVENTION RELATES TO AN EXERCISE 1 AMMUNITION INTENDED TO BE FIRED AT SUPERSONIC SPEEDS. THE INVENTION INCLUDES AN INTERMEDIATE PART 1 WHICH IS PROVIDED WITH A SENSITIVELY CYLINDRICAL PIN 2 FORWARD AND WITH A TRUNK OF A TAIL 3 TO THE REAR. THE PIN HAS A LENGTH CORRESPONDING TO 1.7 TIMES THE DIAMETER OF INTERMEDIATE PART 1. THE BALLISTIC PROPERTIES OF THE AMMUNITION ARE PRACTICALLY IDENTICAL TO THOSE OF NORMAL AMMUNITION UP TO MEDIUM DISTANCES, BUT THE MAXIMUM RANGE OF THE AMMUNITION IS VERY LOWER THAN THAT OF A NORMAL AMMUNITION, FOR EXAMPLE OF THE ORDER OF HALF. APPLICATION TO EXERCISE AMMUNITION FOR CANNONS.

Description

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  The present invention relates to a supersonic ammunition, preferably exercise or driving, having an intermediate cylindrical portion to which are connected a substantially cylindrical section forming the nose, in the form of a pin whose diameter is much smaller than that of the intermediate part, and a tail section. Normal ammunition is usually replaced by special exercise or training ammunition during periods of military training to reduce the cost of shooting.

  the ballistic properties of the exercise ammunition corres-

  substantially to those of the normal ammunition they replace. Several types of ammunition are already known.

Exercise.

  It has been assumed until now that obtaining corresponding ballistic properties up to a predetermined distance also necessitated, for example, correspondence

  the maximum range of a particular ammunition

  with the maximum firing range of the particular normal ammunition it replaces. This also means that relatively large areas must be closed so that

  military training periods can take place.

  The invention relates to an ammunition which allows the use of training grounds much smaller than those used until now. It is based on the knowledge of the favorable ballistic properties of a spindle According to the invention, the ammunition has a nose in the form of a pin whose length and design are such, and a tail section whose connection to the part

  intermediary and the design are such that the ammunition has practical

  ballistic properties as the normal ammunition of fire, which it replaces, up to a predetermined distance of fire, but whose maximum range is reduced compared with that of the normal ammunition, and corresponds for example to the

  half of the maximum range of such a normal ammunition.

  An important feature of the ammunition

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  of exercise according to the invention is the length of the spindle

  cylindrical, compared to the outer diameter of the inter-

  In an advantageous embodiment of the invention, this length is between 1.6 and 2.0 times the diameter of the intermediate portion and, preferably, between 1.65 and 1.85 times this diameter, very advantageously 1.7 times this

  diameter of the intermediate part.

  The following description describes more precisely

  the characteristics of a particular embodiment

  as well as those of the tail section of the projectile.

  The use of a pin-shaped nose provoked

  that the formation of a dead zone for airflow around the spindle at supersonic speeds, so that the braking effect of the front radial surface is eliminated However, at speeds below the speed of sound , the airstream follows the surface of the spindle and the

  front radial surface, so that an important braking force

  aunt is exerted on the munition This behavior indicates that

  the ammunition has a ballistic trajectory that is not practical

  not disturbed at supersonic speeds, but as soon as ammunition velocity has fallen below

  sound, a significant braking force is applied to it.

  Because of this braking force, the maximum firing range obtained is significantly reduced. The spike increases the stability of the ammunition at supersonic speeds as well as at speeds below the speed of sound as well as during the supersonic passage. this pin-shaped nose allows for a considerable increase, worth

  up to one diameter, the distance

  between the points Tp and Tc, de fi ned in the remainder of this memo. The particular configuration of the tail section

  also contributes to the stability of the ammunition This

  original ration makes efficient and cost-effective production of cold compression ammunition possible

  cold compression allows an increase in resistance

  This property also eliminates the risk of the formation of sloping fins during a heat treatment. Cold compression allows the compression of the munition in the form of mechanical compression of the munition so that the thermal treatment of the body of the projectile can be superfluous.

  practically finished product in a single operation.

  Only small filming operations and the application

  a drive band and a guide belt, if any

  are needed after compression It should be noted

  that the configuration of the ammunition and the process of

  allow significant savings on materials,

energy and prices.

  Other features and advantages of the invention

  tion will become more apparent from the following description,

  with reference to the accompanying drawings in which: Figure 1 shows an exercise projectile, in perspective and seen from below; Figure 2 shows the projectile of Figure 1 in perspective from the front; Figure 3 is a side elevation of the projectile of Figures 1 and 2;

  FIG. 4a is a diagrammatic elevation

  sensing the conditions of airflow at supersonic velocities around the exercise projectile of Figures 1 to 3;

  Figure 4b is a schematic side elevation

  as representing the conditions of flow of air at speeds below the speed of sound, in the case of the training projectile of Figures 1 to 3; FIG. 5a is a ballistic diagram corresponding to a predetermined firing distance, in the case of an exercise projectile according to the invention and a corresponding normal firing projectile; FIG. 5b is a ballistic diagram representing the maximum firing range of an exercise projectile according to the invention and a corresponding normal projectile; FIG. 6a is a side elevation of a cylindrical part used as a starting element when

  the manufacture of a projectile according to the invention by compres-

cold injection; and

  Figure 6b is a schematic side elevation

  the time of manufacture during which the training projectile took its final form, in a

  compression tool represented symbolically.

  Figures 1 to 3 show an exercise projectile which comprises a substantially cylindrical intermediate portion 1, to which are connected a spindle-shaped nose 2 and a tail section 3. Such a spindle 2 is already known. The spindle-shaped nose is substantially cylindrical and has a diameter d which is much smaller than the outer diameter D of the cylindrical part and, in one example, it may be noted that the diameter d of the spindle is approximately equal to one third of the diameter D of the intermediate part The tail section

  has a number of fins 3a, for example 6 in number.

  The cylindrical spindle 2 has a length L which, in this embodiment, is about 1.7 times the diameter D of the intermediate part. This size L can, however, vary with the diameter, the type of munition, etc. between 1, 6 and 2.2 times the diameter D and preferably between 1.65 and

1.85 times this diameter.

  The length L 2 of the tail section exceeds the lengths L and L 3 of the pin 2 and the intermediate portion 1 respectively The fins are arranged longitudinally, and they correspond to the gauge along the largest

  part of the tail section However, at the level of the

  With the intermediate part, the fins have a decreasing dimension, the outer surfaces 3 having edges of the fins approaching towards the front, on the side of the intermediate part. The rear end of the intermediate part has a frustoconical shape. the angle Cd which is between and 200, and which is preferably 150 The frustoconical surface has its vertex turned towards the rear so that its dimension corresponds to that of the fins at their anterior ends The length of the frustoconical portion is range

  between 1 and 3% and preferably of the order of 2% of the

  The role of this frustoconical part is to direct the longitudinal flow of air flowing along the external surface of the intermediate part.

  to the space between the fins so that the stability

the projectile is increased.

  The length L 3 of the intermediate part is lower in this case both that of the spindle and that of the tail section The intermediate part has a front annular groove and a rear annular groove intended

  to accommodate a front guide band 4 and a drive band

  The guide strip and the drive strip are formed from a plastic material, for example an acetal or a

another corresponding material.

  In FIG. 3, the reference Tp indicates the center of gravity and the reference Tc indicates the center of gravity.

  pressure, and the distance between Tp and Te is important.

  for the stability of the projectile, this distance being indicated by the reference A. FIGS. 4 a and 4 b represent the conditions

  of airflow at supersonic and subsonic velocities

  the projectile In Figure 4a, the shock wave corre-

  laying on the compression of the air carries the reference 6 and a dead zone in the form of a symmetrical zone in rotation around

  the spindle of the projectile is marked with the reference 7.

  This zone is limited by the external lateral face of the spindle, a radial front surface 1b of the intermediate portion and an imaginary external frustoconical surface 8 formed between the front end surface of the spindle and the periphery of the front radial surface 1b. undisturbed air flow flows in the direction of the arrows 9 along the frustoconical outer surface 8 of the rectilinear generator, so that no braking effect of the projectile is created by the

radial front surface.

  This behavior shows that at super speeds

  sonic, the projectile has a ballistic trajectory similar to that of a projectile having an ogival nose, a conical nose or a corresponding shape The pin-shaped nose causes the rearward displacement of the points Tp and Tc, following

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  the longitudinal axis of the projectile, and increases the distance A so that the high stability desired for the projectile is guaranteed It should be noted that the projectile is stable not only at supersonic speeds but also during the transition between supersonic and subsonic speeds and

to these.

  Figure 4b shows the traffic conditions

  The air stream 10 then follows the outer side face of the spindle and the forward radial surface 1b of the intermediate portion. As a result, this forward radial surface has a braking effect of the projectile whose velocity is reduced so that the maximum range of fire is reduced, for example to half

  of that of a normal shooting shot.

  Figures 5a and 5b show the ballistic properties of the exercise projectile, compared to those

  of a corresponding normal projectile of fire

  tif, the comparison is for a 9 cm standard "Bofors" projectile, model 77, with a weight of about 3.7 kg The exercise projectile also has a 9 cm caliber and a weight

  about 3 kg The y axis represents the height of the trajec-

  in meters, and the x-axis firing distance, also indicated in meters. The predetermined maximum range of the

  corresponding ammunition is 800 meters.

  The trajectory corresponds to the normal projectile and the trajectory b to the exercise shot fired by a muzzle velocity gun Vo = 670 m / s and Vo = 715 m / s respectively. It is obvious that the ballistic properties are substantially the same. same for both projectiles up to a predetermined distance of fire, so that representative periods of exercise can be undertaken with

implementation of the gun.

  The diagram in Figure 5b represents the ballistic trajectories for the maximum range of fire, the y axis representing the height and the x axis the distance measured horizontally, in meters The trajectory a 'of the normal projectile is more than double (6 000 m) of the maximum range

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  of the exercise projectile This behavior is due to the considerable braking of the flight of the training projectile at subsonic speeds It should be noted that the projectile is stable at all speeds, for example between 0 and 3 times the speed of the sound This property shows that bursts of ammunition shooting exercise can be easily followed and found. The described exercise projectile is preferably formed by a cold pressing method In this case, a workpiece is placed in a cold compression tool, and the projectile is manufactured in the tool in a single step so that the spindle-shaped nose and fins are made in a single work operation The projectile is completed during a small work of turning to the desired diameter,

on a ride.

  FIG. 6a shows a part 11 used as an initial element, for example for an exercise projectile

  The piece comprises a cylindrical body having a diameter of

  The compression tool halves are identified by the references 12 and 12 '. The compression is carried out in a single step and FIG.

  represents the finished product in the tool, the separation plan

  As the body of the projectile has been compressed and then removed from the tool, it is machined to the configuration and final dimensions, for example so that the body of the projectile is compressed and removed from the tool. he corresponds

  in the embodiment of Figure 3 The length of the projection

  finished tile is in this case approximately 465 mm.

  Compression methods are already known

  cold and they are not described in detail.

  An important characteristic of the munition according to the invention is that it is well suited to a production

in large series.

  It is understood that the invention has been described and shown only as a preferred example, and that any technical equivalence can be provided in its

  constituent elements without departing from its scope.

  For example, the invention is not limited to exercise ammunition, but can also be used for

normal ammunition firing.

Claims (5)

  1 supersonic ammunition, in particular for   exercises, of the type which comprises a cylindrical   intermediate (1) to which is connected a substantially cylindrical nose section forming a pin (2) having a diameter (d) much smaller than the diameter (D) of the intermediate portion, and a tail section (3), characterized in that that the length (L 1) and the configuration of the spindle, and the configuration and connection of the tail section on the intermediate portion are such that, up to a predetermined distance of firing, the munition has substantially the same ballistic properties as a corresponding normal ammunition of fire, but has a maximum range of fire significantly reduced compared to that of such a normal ammunition firing, this maximum range being for example of the order of half of that of the normal ammunition.   Ammunition according to Claim 1, characterized in that the spindle (2) has a length (<1) of between 1.6 and 2.0 times the diameter (D) of the intermediate part,   preferably between 1.65 and 1.85 times this diameter.   3 Munition according to claim 2, characterized in that the spindle (2) has a length (L 1) which is of the order   1.7 times the diameter (D) of the intermediate part.   4 Ammunition according to any one of the claims   characterized in that the tail section (3) is relatively long and its length (L 2) exceeds the lengths of the intermediate portion and the spindle, and the   tail section is provided with longitudinally arranged fins (3a)   dinalement and having a diameter corresponding to the caliber, over most of the length (L 2) of the tail section. Ammunition according to claim 4, characterized   in that the intermediate part (1) comprises, at its end   rear tee, a frustoconical portion (la) having an axial length of between 1 and 3% and preferably of the order of 2% of the total length (L 1 + L 2 + L 3) of the ammunition, and the front end of the fins has a clearance to a dimension less than the size, the outer surfaces of the edges of the fins (3 a ') approaching forward so that they take a dimension corresponding to that of the end most small frustoconical section (la) of the intermediate part.   6 Munition according to any of the claims   tions, characterized in that the intermediate part   1 (1) comprises a guide strip (4) formed of a plastic material, and a drive band (5) also formed of a plastic material.