GB1605349A - Projectiles for dispensing cloud decoys - Google Patents

Projectile for scattering electromagnetic chaff. The projectile includes a packet of chaff which is enclosed in a tubular case itself arranged in a cylindrical bore made in the body of the projectile, the bottom parts of the said bore and of the said case each being provided with a discharge charge for the purpose of successively ejecting the case then the packet of chaff. It is characterised in that it additionally includes a second packet of chaff enclosed in a second tubular case, the bottom part of which is secured to that of the first case and is, like the bottom part of the first, provided with a discharge charge so that the ejection of the second packet of chaff takes place in the opposite direction to that of the first. Application to protection against electromagnetically guided missiles. <IMAGE>

(54) PROJECTILES FOR DISPENSING CLOUD DECOYS IlWe, SocaE E. LAcRorx of Route de Toulouse, 31 Muret, France, a French Corporate Body do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to projectiles intended essentially for scattering in the form of a cloud, in a selected area of space, a number of electromagnetic decoys, in such manner as to falsify or jam the guidance system of any missile from which protection is desired.The electromagnetic decoys most frequently used are those known as "chaff', consisting of small needle-shaped metallic strips of synthetic material, each of which constitutes a dipole of which the resonant frequency depends upon the length of the strip.

For the purpose of creating rapidly in a given area in space a cloud of electromagnetic decoys it has already been proposed to use a projectile in which a package of decoys is enclosed in a tubular case intended to be ejected from a cylindrical bore and having in its base an expulsion charge for the purpose of ejecting the package of decoys which it contains.

With a projectile of this kind the cloud obtained by the dispersal of the decoys remains relatively small in size (of the order of a few metres at the most) in view of the fact that the decoys, which are extremely light in weight, are very rapidly braked by the air when ejected from the case.

The aim of the invention is a projectile which is capable of producing a much more extensive cloud of electromagnetic decoys than it was possible lo achieve with previous projectiles.

In accordance with the present invention therefore there is provided a projectile for dispersing electromagnetic decoys in the form of a cloud in which a package of decoys is enclosed in a tubular case which, in use, is to be ejected from a cylindrical bore formed in a body of substantially cylindrical shape capable of itself being launched in space with some degree of velocity in the form of a shell, and which has in a base, an expulsion charge for ejecting the package of decoys which it contains, characterised in that it has in addition a second package of decoys enclosed in a second tubular case, a base of which is integral with that of the first case and is provided, like the latter, with an expulsion charge such that the second package of decoys is ejected in the direction opposite to that in which the first package is ejected.

The firing of the expulsion charges in the packages of decoys is preferably controlled by a spring loaded striker which is designed, when both cases have been ejected, to hit a priming charge connected to the aforementioned charges by a pyrotechnic delay. Firing of the charges in this manner provides a safety device for the suitable ejection of both packages of decoys by preventing in particular any ejection of the second package before the second case is completely clear of the bore.

In accordance with one advantageous arrangement, one at least of the two packages of decoys is arranged in a sealed cylindrical envelope in the form of two separate complementary half-shells, thus avoiding too rapid a dispersal of the package of decoys concerned when this envelope is ejected from the relevant case.

The aforementioned cylindrical bore may be formed in a cylindrically shaped body which is itself capable of being launched into space in the manner of an artillery shell.

The invention also relates to a projectile as defined above when contained within the cylindrical bore of said substantially cylindrical body, characterised in that the ejection of the tubular cases from the bore is achieved by means of an expulsion charge located in a base of the bore and fired by means of a delay cord which is ignited when the substantially cylindrical body is launched.

A better understanding of the invention will however be obtained by reference to the following description by reference to the accompanying drawings of a preferred embodiment of the invention in which: Figure 1 is a longitudinal section through a projectile; Figure 2 is a section along line II-II of Figure 1.

Referring now to the drawings, there is shown a device 10 intended to introduce into a given area in space an image of electromagnetic decoys, capable of jamming and/or falsifying the guidance system of a missile from which protection is desired.

The device 10 consists essentially of a light alloy body 14 of substantially tubular shape having a base 12 and a payload 16 arranged in the internal cylindrical bore 18 of the tubular body 14.

The body 14 of the device 10 may, as shown in Figure 1, have an outer cylindrical shape to enable it to be launched in space with a certain velocity in the manner of a shell. The device 10 then constitutes a projectile which can be fired from a gun in association with a case (not shown) containing an appropriate pyrotechnic expulsion charge. When this charge is fired, it is capable of suddenly generating a large quantity of hot gases under considerable pressure, for example of the order of 40 bar.

These hot gases under pressure impinge upon the base 12 of the projectile 10 and eject it from the gun at a velocity which may for example be of the order of 60m/s.

In another, but not shown, embodiment, the body 14 forms a case of which the base 12 has in a conventional manner an annular thrust shoulder or an external annular throat for the positioning and extraction of the case in the delivery gun.

The base 20 of the borel8, which is defined by the base 12 of the projectile 10, has a circular recess 22 in which there is arranged a primary pyrotechnic expulsion charge 24 consisting for example of gunpowder. The charge 24 is held in the recess 22 by means of a disc 26 made of paper or the like held in position on the base 20 of the bore 18 by means of a thrust washer (or plate) 28 arranged between the base 20 and the payload 16 in such manner as to permit the ejection of the latter from the bore 18 following the firing of the charge 24. A removable plug 30 seals the open end of the bore 18 of the tubular body 14 with the addition of a sealing ring 32. The plug 30 can be held in position by means of one or more pins 34 capable of being sheared in order to permit the ejection of the payload 16. In the example shown the plug 30 is of cylindrical shape.It could, however, be ogival, thus enhancing the penetration into the air of the device 10 in the example shown, in which the latter constitutes a projectile.

The firing of the primary charge 24 can be controlled by any suitable means. Provision should be made for a given delay on the same assumption that the device 10 will be launched into space. In the proposed form of embodiment the firing of this charge is controlled by two identical pyrotechnic fuses 36 arranged in two parallel bores 38 in the base 12 and extending into the recess 22. The fuses 36, the buming time of which may for example be of the order of 1 second, are ignited by the hot gases generated for the ejection of the projectile 10. In the form of embodiment shown in Figure lit will be noted that the rear end of the base 12 is hollow and has a steel spring washer 40 and a thin aluminium disc forming a pad 42 held firmly on the base 12 by the crimping of a washer 44 with an interposed sealing ring 46.

The disc 42 is of sufficiently small thickness to be capable of being perforated in the middle, at right angles to the central opening of the spring washer 40, by the hot gases which eject the projectile and thus permit the ignition of the delays 36.

The payload 16 of the device 10 which constitutes in fact the actual projectile consists essentially of a central cast aluminium section 48 and two aluminium tubular cases 50 and 52 arranged in line on either side of the central section 48 to which they are attached and sealed by any suitable means. In the example shown such attachment is effected by the crimping at 54 of each case in an annular throat 56 arranged in the central section 48.

The upper case 50 contains a package of electromagnetic decoys 58 consisting for example of small needle-shaped metallic strips of synthetic material of a given length and known in the art as "chaff'. The package of chaff 58 is formed inside an envelope 60 of plastic material consisting, in the example shown, of several complementary and separate lateral segments (for example three) cylindrical in shape and arranged between a front circular end plate 62 and a rear circular end plate 64 separate from the first plate and inserted preferably in a sealed manner in the case 50.

The end plate 62 is constituted advantageously by the inner section of the plug 30, a section which is inserted in the open end of the case 50 and held there by any suitable means such as one or more pins 66 capable of being sheared.

The base 68 of the case 50 has a circular recess 70 arranged in the central section 48, in which recess a secondary pyrotechnic expulsion charge is held in position by means of a disc 72 made of paper or the like. The charge 74 when fired is adapted to eject from the case 50 the package of chaff 58 on which it acts by means of a light alloy thrust washer 76 located between the end section 64 of the envelope 60 and the base 68 of the case 50.

Similarly, the case 52 contains a package of electromagnetic decoys 78.

The package 78 may in fact, as shown, consist of several small packages 80 in juxtaposition containing chaff of different lengths and thus sensitive to different wavelengths. The packages 80 are preferably separated from one another by inserts 81.

The package 78 is formed inside a cylindrical envelope 82 made of plastic material and consisting, like the envelope 60, of at least two separate but complementary segments. In the preferred form of embodiment shown, the envelope 82 is composed of two complementary symmetrical half-shells each of which has a circular end section 84 or 86 and a cylindrical wall section 88 or 90. In other words, the cylindrical wall section 88 is integral with the end section 84 to form one of the half-shells while the wall section 90 is integral with the end section 86 to form the other half-shell. These two end sections 84 and 86 are inserted in the case 52 with interposed annular sealing rings 92 and 94 respectively.The end section 86 is held in position on the open end of the case 52 by any suitable means such as one or more pins 96 which can be sheared, the outer shape of this section 86 following closely that of the aforementioned thrust washer 28.

The base 98 of the case 52 has a circular recess 100 arranged in the main section 48, in which a secondary pyrotechnic expulsion charge 104 is held in position by means of a disc 102 made of paper or the like. The charge 104 when fired is designed to eject from the case 52 the package of chaff 78 in the envelope 82 on which it acts by means of a light alloy thrust washer 106 inserted between the end section 84 of the envelope 82 and the base 98 of the case 52.

The firing of the secondary expulsion charges 74 and 104 is controlled simultaneously by an initiating device denoted by the general reference 108, which is initiated when the projectile constituted by the payload 16 is ejected from the bore 18. More precisely, the initiating device 108, if reference is made to Figure 2, consists of a striker 110 mounted pivotally around a shaft 112 carried by the central section 48, and stressed by a torsion spring 114 in an anticlockwise direction, if reference is made to Figure 2, that is, in the direction corresponding to that in which it abuts a stop on the wall of the bore 18. The striker 110 is intended, when the payload 16 is ejected, to strike, under the effect of the spring 114, a pyrotechnic primer 116 fixed in the section 48 and designed to ignite a pyrotechnic delay 118 compressed in a transverse passage 120.This passage leads into a longitudinal passage 122 which connects the opposite circular recesses 70 and 100 of this section 48 and which is itself filled with a pyrotechnic composition similar to that used for the charges 74 and 104. The delay 118 is intended as a safety device for the expulsion of the package of chaff 78, ensuring in effect that the charge 104 will be fired only when the case 52 has been completely ejected from the bore 18. As an illustration, the burning time of the delay 118 may be of the order of 0.1 to 0.2 second. A gas pon 124 is preferably arranged between the primer 116 and the delay 118 to permit the evacuation of any excess gases in the space formed between the section 48 and the bore 18.

The functioning of the projectile 10 described above is as follows: The firing of the launching charge (not shown) causes the projectile to be expelled from the gun at a high speed by the hot gases liberated. These gases have simultaneously burst the pad 42 and fired the delays 36. On complelion of the burning of the latter, approximately 1 second for example after firing, the primary expulsion charge 24 is ignited and drives the payload 16 out of the bore 18, shearing the pins 34. When this expulsion occurs, the striker 110 is released and strikes the primer which ignites the delay 118. After the latter has finished buming (for example for 0.1 second) the secondary charges 74 and 104 are fired simultaneously and cause the ejection in opposite directions of the packages of chaff 58 and 78, shearing respectively the pins 66 and 96.The separation of the envelope 60, followed by the separation of the envelope 82, permits the dispersal of the chaff under the effect of the braking action of the air. It will be noted that the construction of the envelope 82 as two halfshells somewhat retards its "opening", and consequently the dispersal of the packages of chaff 80.

It is to be clearly understood that the invention is not resuicted to the form of embodiment shown and that numerous modifications conceming in particular the specific constitution of the decoys, the initiating device 108, the shape and method of launching the projectile 10, the burning time of the various delays 36 and 118 and so forth, can be envisaged within the ambit of this patent specification. In particular, the electromagnetic decoys used could be different from the type of electromagnetic decoys (chaff) considered in this patent specification and could consist of any other type of known electromagnetic decoys.It will be seen that the central section 48 separates the two packages of decoys 58 and 78 and that it is possible to make provision for the latter by using two types of electromagnetic decoys which differ in basic design and in operation without any fear that one of these types may have a destructive effect on the other.

WHAT WE CLAIM IS: 1. A projectile for dispersing electromagnetic decoys in the form of a cloud, in which a package of decoys is enclosed in a tubular case which, in use, is to be ejected from a cylindrical bore formed in a body of substantially cylindrical shape capable of itself being launched in space with some degree of velocity in the manner of a shell, and which has, in a base, an expulsion charge for ejecting the package of decoys which it contains, characterised in that it has in addition a second package of decoys enclosed in a second tubular case a base of which is integral with that of the first case and has, like the base of the first case, an expulsion charge such that the second package of decoys is ejected in the direction opposite that in which the first package is ejected.

2. A projectile in accordance with Claim 1, characterised in that the expulsion charges of the two packages of decoys are interconnected by means of a passage in the integral bases of the two cases whereby they are fired simultaneously.

3. A projectile in accordance with Claim 2, characterised in that the firing of the expulsion

**WARNING** end of DESC field may overlap start of CLMS **.

1. **WARNING** start of CLMS field may overlap end of DESC **.

   section 86 to form the other half-shell. These two end sections 84 and 86 are inserted in the case 52 with interposed annular sealing rings 92 and 94 respectively. The end section 86 is held in position on the open end of the case 52 by any suitable means such as one or more pins 96 which can be sheared, the outer shape of this section 86 following closely that of the aforementioned thrust washer 28.

   The base 98 of the case 52 has a circular recess 100 arranged in the main section 48, in which a secondary pyrotechnic expulsion charge

   104 is held in position by means of a disc 102 made of paper or the like. The charge 104 when fired is designed to eject from the case 52 the package of chaff 78 in the envelope 82 on which it acts by means of a light alloy thrust washer 106 inserted between the end section 84 of the envelope 82 and the base 98 of the case 52.

   The firing of the secondary expulsion charges 74 and 104 is controlled simultaneously by an initiating device denoted by the general reference 108, which is initiated when the projectile constituted by the payload 16 is ejected from the bore 18. More precisely, the initiating device 108, if reference is made to Figure 2, consists of a striker 110 mounted pivotally around a shaft 112 carried by the central section 48, and stressed by a torsion spring 114 in an anticlockwise direction, if reference is made to Figure 2, that is, in the direction corresponding to that in which it abuts a stop on the wall of the bore 18. The striker 110 is intended, when the payload 16 is ejected, to strike, under the effect of the spring 114, a pyrotechnic primer 116 fixed in the section 48 and designed to ignite a pyrotechnic delay 118 compressed in a transverse passage 120.This passage leads into a longitudinal passage 122 which connects the opposite circular recesses 70 and 100 of this section 48 and which is itself filled with a pyrotechnic composition similar to that used for the charges 74 and 104. The delay 118 is intended as a safety device for the expulsion of the package of chaff 78, ensuring in effect that the charge 104 will be fired only when the case 52 has been completely ejected from the bore 18. As an illustration, the burning time of the delay 118 may be of the order of 0.1 to 0.2 second. A gas pon 124 is preferably arranged between the primer 116 and the delay 118 to permit the evacuation of any excess gases in the space formed between the section 48 and the bore 18.

   The functioning of the projectile 10 described above is as follows: The firing of the launching charge (not shown) causes the projectile to be expelled from the gun at a high speed by the hot gases liberated. These gases have simultaneously burst the pad 42 and fired the delays 36. On complelion of the burning of the latter, approximately 1 second for example after firing, the primary expulsion charge 24 is ignited and drives the payload 16 out of the bore 18, shearing the pins 34. When this expulsion occurs, the striker 110 is released and strikes the primer which ignites the delay 118. After the latter has finished buming (for example for 0.1 second) the secondary charges 74 and 104 are fired simultaneously and cause the ejection in opposite directions of the packages of chaff 58 and 78, shearing respectively the pins 66 and 96.The separation of the envelope 60, followed by the separation of the envelope 82, permits the dispersal of the chaff under the effect of the braking action of the air. It will be noted that the construction of the envelope 82 as two halfshells somewhat retards its "opening", and consequently the dispersal of the packages of chaff 80.

   It is to be clearly understood that the invention is not resuicted to the form of embodiment shown and that numerous modifications conceming in particular the specific constitution of the decoys, the initiating device 108, the shape and method of launching the projectile 10, the burning time of the various delays 36 and 118 and so forth, can be envisaged within the ambit of this patent specification. In particular, the electromagnetic decoys used could be different from the type of electromagnetic decoys (chaff) considered in this patent specification and could consist of any other type of known electromagnetic decoys.It will be seen that the central section 48 separates the two packages of decoys 58 and 78 and that it is possible to make provision for the latter by using two types of electromagnetic decoys which differ in basic design and in operation without any fear that one of these types may have a destructive effect on the other.

   WHAT WE CLAIM IS: 1. A projectile for dispersing electromagnetic decoys in the form of a cloud, in which a package of decoys is enclosed in a tubular case which, in use, is to be ejected from a cylindrical bore formed in a body of substantially cylindrical shape capable of itself being launched in space with some degree of velocity in the manner of a shell, and which has, in a base, an expulsion charge for ejecting the package of decoys which it contains, characterised in that it has in addition a second package of decoys enclosed in a second tubular case a base of which is integral with that of the first case and has, like the base of the first case, an expulsion charge such that the second package of decoys is ejected in the direction opposite that in which the first package is ejected.

2. 2. A projectile in accordance with Claim 1, characterised in that the expulsion charges of the two packages of decoys are interconnected by means of a passage in the integral bases of the two cases whereby they are fired simultaneously.

3. 3. A projectile in accordance with Claim 2, characterised in that the firing of the expulsion

   charges of the packages of decoys is controlled by a spring loaded striker designed, on the ejection of the two cases from the cylindrical bore, to strike a primer charge connected to the aforementioned charges by a pyrotechnic delay.

4. 4. A projectile in accordance with any of Claims 1 to 3, characterised in that at least one of the packages of decoys is composed of several small packages, separated by inserts, of electromagnetic decoys sensitive to different wavelengths.

5. 5. A projectile in accordance with any of Claims 1 to 4, characterised in that at least one of the packages of decoys is arranged in a sealed cylindrical envelope having at least two separate independent and complementary sections.

6. 6. A projectile in accordance with Claim 5, characterised in that the envelope is in the form of two half-shells, each composed of a circular end section and a semi-cylindrical wall section.

7. 7. A projectile in accordance with Claim 5, characterised in that the envelope has two independent circular end plates and at least two complementary cylindrical wall sections lying between these two plates.

8. 8. A projectile in accordance with any of claims 1 to 7 when contained within the cylindrical bore of said substantially cylindrical body and characterized in in that the bore has a base containing an expulsion charge for ejecting the tubular cases from the bore.

9. 9. A projectile in accordance with claim 8 and including a delay cord, which is ignited when the substantially cylindrical body is launched, for firing the expulsion charge.

10. 10. A cartridge for introducing into space a number of electromagnetic decoys and comprising a projectile as claimed in Claim 8 or Claim 9 in association with a case containing in its base a pyrotechnic charge for the expulsion of said body with said projectile contained therein.

11. 11. A projectile constructed substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

12. 12. A device comprised of a projectile contained within a cylindrical body and adapted to operate substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.