IL39741A

IL39741A - Illuminating rocket propelled projectiles equipped with parachute

Info

Publication number: IL39741A
Application number: IL39741A
Authority: IL
Inventors: A Makov
Original assignee: Israel State
Priority date: 1972-06-22
Filing date: 1972-06-22
Publication date: 1977-01-31
Also published as: IL39741A0; DE2327827A1; NL7308554A; FR2189703A1

Description

nasoa n»T> on Illuminating, rocket propelled projectiles equipped with paraohute THE STATE OF ISRAEL, MINISTRY OF DEFENCE The inventor: Abraham ako C-36944 39741/2 This invention relates to illuminating, rocket propelled .projectiles of the kind, hereinafter referred to 'as being of the kind specified, having an illuminant mass coupled to a parachute such that, at a predetermined instant during flight, component portions of the projectile become detached from each other, the parachute is released and the ignited illuminant mass slowly descends under the extended parachute.

With projectiles of this kind a danger always exists that, during the flight, the separating portions of the projectile will collide with each other and that, in particular the opening of the parachute will be thereby, fouled. Furthermore, the strain exerted on the parachute and on the cords linking the parachute to the illuminant mass is a direct function of the -speed of the projectile when the parachute is released. Thus the higher the speed the greater the strain and the consequently increased expense in providing parachutes capable of withstanding such strains.

It is an object of the present invention to provide a new and improved illuminating projectile of the kind specified wherein these dangers and expenses are substantially reduced.

According to the present invention there is provided an illuminating rocket propelled projectile of the kind specified comprising at least two axially aligned projectile portions coupled together about mutually pivotable surfaces , a leading portion constituting a canister assembly and including an illuminant mass and a parachute, a rear portion including a rocket motor, a leading face of said leading portion being located obliquely with respect to an axial plane of the projectile, an exteimal housing with said leading portion releasably located therein and being releasably couple to the rear portion, a parachute housing located within the leading portion and releasably coupled to said illuminant mass, a time fuze for detaching said external housing from said rear portion and to releas said leading portio and a dela element and an expelling charge for uncoupling said parachute housing with respect to the illuminant mass a predetermined time delay after the Ignition o the time fuze.

Preferably said leading portion constitutes a canister assembly whilst the rear portion Includes the rocket motor.

Preferably said external housing includes an ogival nose which completely encloses said leading portion and is coupled to the other portion by first shearable means.

In use, the time fuze is ignited at a predetermined time after launching of th projectile and as a consequenc the external housing is detached and the fi st and second portions are uncoupled. With the detaching of the external housing the oblique leading face of the leading projectile portion is uncovered and, when this is exposed to th air stream the pivotable surfaces pivot with respect to each other and the leading portion is displaced out of the initial trajectory of the projectile. The uncoupled projectile portions separate, the second portion continuing along the original tranectory as does the previously detached external housing. The leading projectile portion having been diverted from the original trajectory cannot therefore collide with the other components.

Furthermore, the leading portion not being provided with stabilizing fins rolls about an axis transverse to its trajeotory, resulting in increased air drag. The speed of propulsion of the leading portion is thus steadily reduced during the burning time of the delay element so that by the time the parachute housing is expelled and the parachute released, the speed has sufficiently reduced for a minimal strain to be exerted on the parachute and its cords.

For a better understanding of the present invention and to show how the same may be carried out in practice reference will now be made to the accompanying drawings in which: Fig. 1 is a schematic drawing of a rooket driven illuminating projectile in accordance with the present invention, Fig. 2 is a longitudinally sectioned view of the leading portion of the projectile shown in Fig. 1, and Fig. 3 illustrates schematically the various stages beginning with the projectile in flight and ending in the downward descent of the illumlnant mass under its opened parachute.

As seen in Eigs. 1 and 2 of the drawings,, the projectile comprises aligned first and second axial portions 1 and 2, the leading portion 1 constituting a canister c, assembly nclosed within an external housing 3, whilst the second portion 2 includes a rocket motor and terminates in stabilizing fins 4. The external housing 3 terminates in and is secured to a nose portion 5 (containing a time fuze) . The end of the external housin 3 remote from the fuze 5 is secured by shearable pine 7 to the front end of the second portion 2.

As seen in Fig. 2, there is located within the leading portion 1 a cylindrical illuminant mass Θ and a parachute 9· The illuminant mass 8 is contained within a tubular casing 10 and is sandwiched between front and rear plates 11 and 12, the front plate 11 being axiall apertured whilst the rear plate 12 is formed with a centrally located recess which accommodates an igniting pellet 13· The external surface of the rear plate 12 is formed with an outwardly extending, centrally disposed spherical bulge 14 which is designed to mate in a corresponding cavity formed inlhe front end of the rocket motor, rear portion 2. The bulge 14 and the cavity constitute mutually pivotahle surfaces.

Extending through the illuminant mass 8 is a tubular conduit 15 which, at one end, extends up to the near vicinity of the pellet 13 and at the other end is screwed Into the front plate 11. A flanged disc 16 having parachute cord supporting lugs 17 is fastened to the front plate 11 by means of a hollow connector 18, screwed into the forward side of the front plate 11. A conduit 19 is screwed to the other end of the connector 18.

The parachute housing Is constituted by a cylindrical member 20 and an end plate 21. Extending through a central aperture in the end plate 21 is an axially bored coupling bolt 22» one end of which is screw-coupled by means of a shearable screw thread 23 to tie end portion of the conduit 19. The other end of the bolt 22 is screw-coupled via a nut 24 to a centrally apertured end plate 25» having an' oblique end face 26.

Located within the conduit 19 are two pyrotechnic devices : a delay element 27 and an expelling charge 28* In use, the -toe fuze 5 is set so as to be ignited a predetermined time after launching of the projectile.

Pig. 3a shows schematically the projectile in flight prior to the ignition of the time fuze 5.

With the ignition of the time fuze 5 the detonation gases thereby generated result in the shearing of the shear pins 7 and the withdrawal of the external housing 3 from the leading portion 1 as seen in Fi * 3b. Thus with the withdrawal of the external housing 3 the oblique face 26 beoomes exposed to the air stream and at the same time the leading portion 1 is effectively uncoupled from the second portion 2. As a result, and as seen in Fig. 3c of the drawings the leading portion 1 swivels with respect to the second portion about their mutually pivot-able bulge and cavity and out of the trajectory of the projectile and eventually separates itself from the ί - 7 - second rocket motor portion which continues on its original trajectory. The detonator gases of the pyrotechnic devices also ignite the delay element 27 via the bore in the holt 22.

The action of the air drag results also in the slowing down of the speed of the leading portion.

This slowin down continues until the delay element 27» which was initially ignited with the ignition of the time fuze 5» burns through and ignites the expelling charge 2Θ. Upon the detonation of the expelling charge the parachute housing 20, 21 and the bolt 22 become detached from the conduit 19 (the thread 23 being sheared as seen in Fig. 3d of the drawings) and the parachute 9 is now exposed to the air stream and is therefore ready for opening out. At the same time, as the expelling charge detonates, an igniting flame passes through the axial bore formed in the connector 18, the front plate 11 and the conduit 15, to the pellet 13 and this in turn ignites, leading to the Ignition of the illumlnant mass. The opening out of the parachute can now safely take place without any danger of collision with the other components of the projectile.

The ignited illumlnant mass now descends slowly under the fully extended parachute, It will be appreciated that by virtue of the fact that the unextended parachute has been diverted from the main trajectory of the projectile in which trajectory the other components of the projectile continue on their course ensures that the parachute is not fouled during its opening by. collision with the other components* Furthermore the fact that, prior to the opening of the parachute, the leading portion containing the parachute has been slowed down in speed, the strain exerted on the parachute and its oords is substantially less than would otherwise be the case and in consequence economies can be carried out in the choice of the paraohute materials.

Claims

_ Q . 39741/2 C CLAIMS 0

1. An illuminating rocket propelled projectile of the kind specified comprising at least tw axially aligned projectile portions coupled together about mutually pivotal surfaces, a leading portion constituting a canister assembly and including an illuminant mass and a parachute, a rear portion including a rocket motor, a leading face of said leading portion being located obliquely with respect to an axial plane of th projectile, an external housing with said leading portion rcileasably located therein and being releasably coupled to the rear portion, a parachute housing located within the leading portion and releasably coupled to said Illuminant mass, a time fuze for detaching said external housing from said rear portion and to release said leading portion and a dela element with an expelling charge for uncoupling said parachute housing with respect to the illuminant mas a predetermined time delay after the ignition of the time fus:e.

2. A projectile according to Claim 1, wherein said surfaces are respectively convex and concave.

3. · A projectile according ½o Claim 1 or 2, wherein said external housing comprises a projectile nos portion.

4. A projectile according to Claim 3, wherein said external housing encloses said leading portion and is , coupled to the subsequent portion by shearable means*

5. A projectile according to any one of the preceding claims, wherein said leading face is formed integrally with said parachute housing*

6. A projectile according to Claim 5» wherein said parachute housing is coupled to said illuminant mass via shearable means.

7. A projectile according to Claim 6, wherein a tubular conduit extends through said parachute housing and is rigidly secured at one end to an illuminant casing and is secured by shearable means at its other end to said parachute housing.

8. A projectile according to Claim 7, wherein said conduit accommodates said delay element and said expelling charge and communicates via an axial bore formed in said illuminant mass with an ignitor pellet.

9. A rocket propelled illuminating projectile substantially as hereinbefore described by way of example and withreference to the accompanying drawings. For the Applicants HOLD COHN AWT PARTNERS IS/rb