Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
  • F42C9/00—Time fuzes; Combined time and percussion or pressure-actuated fuzes; Fuzes for timed self-destruction of ammunition
  • F42C9/14—Double fuzes; Multiple fuzes
  • F42C9/147—Impact fuze in combination with electric time fuze

Definitions

• the present invention relates to a projectile. Moreover, the invention relates to a use of an electronic fuze in such a projectile.
• An armoured vehicle or an airplane has limited space for ammunition, and the targets which may be topical in a combat situation may vary to a large degree and will require different effects from ammunition. This may lead to that the vehicle or airplane has to carry several types of ammunition, of which probably only one is optimized against the target which actually occurs.
• a known so-called "multipurpose" projectile consists in the principle of a nose portion, which may be of aluminium, and which is fastened by being screwed into a hardened steel mantle.
• the nose portion is filled with incendiary charge supported by a support disc with an axial, throughgoing hole.
• forwardly in the mantle is situated another incendiary charge with an axial, not throughgoing hole, and behind this is situated an explosive charge.
• the incendiary charges ignite and develop gases with very high temperature and high pressure. These gases penetrate into the pores of the explosive and deflagrate the explosive, and the projectile is shattered into fragments.
• a deflagration process is a combustion process with a combustion velocity of up to some hundreds of meters per second.
• the velocity of the fragments sideways from the projectile therefore, is low, approximately 300 m/sec. Additionally, the fragments on beforehand already have the velocity of the projectile, whereby the actual velocity of the fragments is substantially higher.
• deflagration is that the projectile is divided in several large fragments. This dividing takes place approximately 0,3 millisec. after the impact of the projectile, and the entire effect is produced inside the target.
• the direction of the fragments is forward in an angle of approximately 15 degrees from the direction of the trajectory of the projectile.
• the size and the direction of the fragments caused by deflagration are very effective against material target components in the target.
• the projectile also causes a substantial fire effect and a far-reaching pressure effect due to the combined effect of deflagration of explosive and the combustion of the incendiary charges.
• detonation is meant an explosive transformation with velocities between 5000 and 10000 m/ sec. Such a process has to be started by means of a shock wave produced by a blasting cap.
• the fragment velocity sideways from the projectile is from 900 to 1500 m/sec.
• Explosive grenades having electronically controlled time fuze having electronically controlled time fuze.
• Grenades of the high-explosive grenade type are also known, having electronical fuzes which permit that these grenades may be caused to detonate in the proximity of the target, i.e. without impact taking place.
• electronical fuzes Different technical designs of such electronical fuzes are known.
• the advantage of such grenades is that they do not have to hit the target directly, and they are, therefore, effective against area targets (targets being somewhat spread) or when the possibility of a direct hit is at a minimum.
• these grenades typically use the detonation properties of the explosive.
• the detonation is initiated by means of an electric blasting cap, which starts the shock wave necessary to start detonation.
• the ignition of the blasting cap takes place by means of an electric impulse being sent to the cap. The moment is determined when the gunner fires the shot.
• the grenade can be caused to detonate in front of, above, rearwardly or beside of the target without coming into direct contact with the target.
• the fragments dispersed from the grenade hit the target.
• the firing control system on the weapon platform determines the distance to the target, for instance by means of laser or a radar distance meter. This distance is calculated into time of flight to the target. This time is encoded into an oscillator in the fuze. When the oscillator has performed the number of oscillations which corresponds to the time of flight, the oscillator opens for the electrical impulse which ignites the blasting cap. The encoding into the fuze takes place in the moment of firing, and the setting of time will be very exact.
• Characteristical for the effect of the fragments is that the fragments are dispersed with a high velocity component sideways from the detonation point of the grenade. This is due to the high fragment velocity. (From 900 to 1500 m/sec.) If the velocity of the grenade in the detonation point is 800 m/sec. and the fragment velocity is 1200 m/sec. on average, the direction of the fragments will be approximately 60 degrees from the firing direction. Lower projectile velocities will cause a larger angle and higher will cause a smaller angle.
• the dispersing angle of the fragments can be increased.
• the projectile must have a ballistic shape, whereby large restrictions are present.
• a grenade will also comprise a device which permits it to be blasted by detonation by a direct impact if the time fuze is not used, or if impact takes place before the time fuze causes detonation.
• the direction of the fragments will, however, be as before; i.e. sideways.
• the projectile according to the invention has an optimum effect by direct impact in material targets such as light armour, airplanes, bunkers, buildings etc., but it also has optimum effect against area targets or airplane targets, provided that the gunner chooses a time fuze function in stead of the direct impact function.
• the grenade acts in the manner that deflagration, and not detonation, is the mode of functioning for the explosive.
• the fragments move forwardly in a conus of approximately 30 degrees.
• the time fuze is used, and which is situated behind the explosive charge, the explosive is ignited by a blasting cap which causes detonation of the explosive.
• a blasting cap which causes detonation of the explosive.
• this explosive will be able to detonate if it receives a shock wave from behind (In order to enable a transfer of a detonation, an explosive must have a certain thickness. The thickness will depend on the type of explosive).
• the fragments will have a low velocity component sideways from the mantle; i.e. that the conus angle for the fragments will be small due to the high forward velocity of the projectile. Moreover, the fragments will be large.
• the grenade will have two main directions with respect to fragment effect when ignited from the rear by the blasting cap, whereby small fragments having a high velocity move sideways from the rearward portion of the mantle with a large conus angle when the explosive charge detonates, while large fragments having a low sideways velocity mainly move forwardly or with a small conus angle when the thin layer of explosive around the incendiary charge detonates.
• the grenade maintains its ability to deflagrate if it hits a target by direct impact, whereby the time fuze will not function.
• the grenade will not loose any of its effect against light armour, bunkers, buildings or airplanes by direct impact.
• the fragments moving sideways will be effective against targets in trenches or behind other coverings.
• Fig. 1 shows an embodiment without explosive immediately behind the nose portion, and with a cavity in the incendiary charge.
• Fig. 2 shows an embodiment where the incendiary charge is surrounded by explosive in the rearmost portion, and where the incendiary charge has a cavity.
• Fig. 3 shows an embodiment where explosive fills a larger part of the space behind the nose portion, and where an incendiary charge is situated in front of this explosive.
• Fig. 4 shows an embodiment without incendiary charge behind the nose portion, and where explosive having a forward cavity fills the space behind the nose portion.
• a projectile comprising a mantle 1 , a nose portion 2 fastened to the mantle 1 by screwing, and a support disc 3 having an axial hole 4, screwed into the rearward end of the nose portion 2, in order to support an incendiary charge 9 situated in the nose portion during launching.
• an electronical fuze 5 which contains an electric blasting cap 6 situated in a forwardly open hole in a transverse wall 7 inside the mantle.
• the incendiary charge 9 constitutes an impact igniter charge, and can be replaced by an impact fuze.
• the mantle 1 is shown surrounded by a guide band 14, in a conventional manner, which provides sealing against gun powder gases during firing and which imparts rotation to the projectile when the launching tube of the weapon has helical flutes.
• the mantle 1 contains a main charge 11 in the form of an explosive charge. Behind this is shown an incendiary charge 13, which for instance can be of zirconium. This charge may, however, be omitted.
• the Figs also show two locking rings 16 for the fuze 5.
• Fig. 1 shows an embodiment where only one incendiary charge 10 is situated behind the nose portion 2.
• the incendiary charge 10 is hollow, having an approximately conical cavity 15.
• Fig. 2 shows an embodiment where the incendiary charge 10 approximately forms a conus having an approximately constant wall thickness, whereby the incendiary charge 10 delimits an interior cavity 15, and explosive 12 fills the cavity around the incendiary charge 10 at the rear thereof.
• Fig. 3 shows an embodiment where explosive 12 fills the rearmost of the space behind the nose portion 2, and where an incendiary charge 10 covers the forwardmost of the explosive and is cup shaped, whereby it delimits a cavity 5 being smaller than the cavity 15 shown in Fig. 2.
• Fig. 2 shows an embodiment where the incendiary charge 10 shown in Figs. 1 - 3 has been omitted, and where the space behind the nose portion 2 contains explosive 12 which delimits a cavity 15 in the forwardmost end.
• the projectile may, as mentioned, be blasted in two different modes. If a small dispersion of fragments from the mantle 1 is desired; i.e. a small conus angle for the fragments, the gunner may choose not to activate the electronical fuze 5 in the base of the mantle. Then, the projectile will be blasted by hitting a target. The transformation of the charges will start from the front, in that the incendiary charge 9 in the nose portion 2 will be ignited and react due to the impact and ignite the remaining charges. The explosive charges 11 and 12 will deflagrate, and the mantle 1 will be shattered into relatively large fragments having a relatively low sideways velocity component.
• the conus angle in which the fragments are dispersed may for instance be approximately 30°.
• a substantial fire effect occurs due to the incendiary charge 10 (for the embodiments of Figs. 1 - 3) and also a pressure effect due to the deflagration of the explosive charges 11 and 12 and the combustion of the incendiary charges 9 and 10.
• the gunner may choose to use the electronical fuze 5 in order to start the transformation of the charges. This is accomplished by determining the distance to the target in the manner mentioned in connection with prior art projectiles containing an electronic blasting cap.
• the electronical fuze 5 determines the time of flight until blasting, and provided that the projectile does not hit any target before the blasting cap 6 receives an electrical ignition impulse, the projectile will be blasted in that the blasting cap 6 ignites the explosive charges 11 and 13 in the embodiments shown in Figs. 2 - 4 and the explosive charge 11 and the incendiary charge 12 shown in Fig. 1.
• Ignition takes place in that the blasting cap 6 activates a shock wave, and the explosive charge 11 (and 12, if present) is transformed by detonation.
• the amount of explosive relatively to the wall thickness of the mantle will influence the conus angle of the fragments.
• the relatively large explosive charge 11 rearmost in the mantle 1 will impart a high sideways velocity component to the fragments from the rearmost of the mantle 1 , and the fragments will be dispersed in a conus having a large conus angle, for instance approximately 60°.
• the projectile according to the invention can be manufactured from materials which are conventionally used for projectiles.
• the mantle and the support disc may be of steel, while the nose portion may be of light metal, for instance aluminium, when it contains an igniter charge.
• the nose portion may for instance be of steel.
• the materials mentioned do not constitute any limitation.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19910997

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (5)

• 2000
  • 2000-04-07 NO NO20001809A patent/NO20001809D0/no unknown
• 2001
  • 2001-04-06 WO PCT/NO2001/000150 patent/WO2001077606A1/en active Application Filing
  • 2001-04-06 AU AU2001258946A patent/AU2001258946A1/en not_active Abandoned

Patent Citations (5)

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