The present invention relates in general to small sub-munitions or warheads and in particular to flechette, dart or arrow-type warheads used to neutralize various target objects such as mines, improvised explosive devices (IEDs). unexploded ordnance and flying projectiles, missiles or rockets.
Systems that employ penetrating devices to defeat unexploded ordnance and/or buried land mines are known. Particularly pertinent to the invention are projectiles such as flechettes, darts or arrows (referred to generally hereinafter as “arrows”) designed to penetrate through dirt, sand, and/or water as well as the casing of targets such as unexploded ordnance or buried land mines, in order to deliver a payload designed to neutralize the explosive material within these targets. These devices use kinetic energy to “break-up” or fracture the explosive material within the target, allowing a neutralizing agent to contact the fractured explosive material. The neutralizing agent is normally some type of material that will burn the explosive material in the target but not detonate it (for example, the hot decomposition products of a propellant) or chemically react with the explosive in the mine in order to complete its neutralization.
Small incendiary or pyrophoric arrows are known. For example, U.S. Pat. No. 4,625,650 discloses an explosive incendiary projectile equipped with a hollow cylindrical as well as aerodynamically configured copper jacket having a tubular penetrator consisting of a heavy metal with an explosive charge. With consideration to the relatively small caliber (12.7 mm), a sufficient penetrating effect with additional lateral effect is alone not achievable due to physical reasons.
U.S. Pat. No. 6,540,175 discloses a dart having an elongated body with a high temperature incendiary fill, a nose section shaped to provide cavitation upon passing through a displaceable mass, firing means including an axially displaceable firing pin operative upon contact with a non-displaceable mass, and a fulminate primer activated by said firing pin communicating with said fill. The high temperature incendiary fill candidates include titanium-boron-Teflon with CTBN as the binder, titanium-boron-Teflon with VitonA as the binder, titanium-boron with ammonium perchlorate with VitonA as the binder, aluminum potassium perchlorate with VitonA as the binder and aluminum iron oxide with VitonA as the binder.
U.S. Pat. No. 6,748,842 discloses a kinetic energy driven projectile for defeating unexploded ordnance or buried land mines. This projectile has been developed to address the specific problem with similar devices in that the kinetic energy by itself does not sufficiently fracture the explosive material within a mine in order to fully defeat the mine. This invention adds a small amount of insensitive high explosive material that is cap sensitive to one tip of the projectile, along with a novel initiation mechanism, so that the detonation of the high explosive material can more fully fracture the explosive material within a mine. This allows a neutralization agent to completely react with all of the explosive material within the mine, thereby consuming the entire fill.
Projectiles that contain a relatively small amount of incendiary or explosive composition cause relatively small resultant explosions or reactions. Additionally, because the incendiary or explosive composition is configured to ignite substantially simultaneously with the impact of the projectile on a target, the explosion or other reactions are often complete before they can inflict substantial additional damage to the target.
There is therefore a need for, and it would be advantageous to have arrows that do not suffer from these disadvantages.
The present invention relates to arrow-type warheads, in particular pyrophoric warheads. In contrast with all known arrows, pyrophoric arrows of the present invention have an incendiary envelope that is consumed in a reaction with a pyrophoric or incendiary filling upon impact.
According to the present invention there is provided an arrow-type warhead including an incendiary envelope and a filling disposed within the envelope and primed to undergo a reaction with the envelope upon impact of the arrow on a target, whereby both envelope and filling are consumed in the reaction to provide a desired destructive effect.
In some embodiments, the filling includes a pyrophoric material in the form of a metal oxide and a metal powder.
In some embodiments, the filling includes a pyrophoric material in the form of a metal oxide and a metal powder.
In some embodiments, the metal is aluminum or magnesium, the oxide is respectively an aluminum or a magnesium oxide and the envelope is made of respectively aluminum or magnesium.
In some embodiments, the metal oxide has a composition above the stoichiometric ratio, thereby leading to an exothermic reaction.
In some embodiments, the filling is incendiary and operative to undergo the reaction with the envelope in an oxygen-rich environment.
In some embodiments, the warhead further includes a hardened head section for promoting penetration of the target, a stabilizing mechanism for stabilizing the warhead in flight and an igniter mechanism for setting off the pyrophoric material.
In some embodiments, the envelope and the stabilizing mechanism form a unibody structure.
In some embodiments, the stabilizing mechanism includes a fixed fin structure.
In some embodiments, the stabilizing mechanism is selected from the group consisting of a stabilizing cup, a stabilizing cone, a stabilizing band and centrifugal foldable radial fins.
In some embodiments, the warhead further includes a stopping mechanism disposed to stop the warhead at a predetermined position relative to the target upon impact.
In some embodiments, the stopping mechanism is selected from the group consisting of a spring mechanism and a collapsible tail mechanism.
In some embodiments, the warhead further includes a mini-rocket propulsion mechanism for propelling the warhead to the target.
According to the present invention there is provided an arrow-type warhead including an envelope, an explosive filling, a hardened head section for promoting penetration of the target and a stabilizing mechanism for stabilizing the warhead in flight.
According to the present invention there is provided an arrow-type warhead including a unibody structure defined by an elongated envelope having a hardened head section at one end and an integrated stabilizing mechanism at an opposite end and a filling disposed within the envelope and primed to undergo an exothermic reaction with the envelope upon impact of the head section on a target, thereby causing target destruction.
For a better understanding of the present invention and to show more clearly how it could be applied, reference will now be made, by way of example only, to the accompanying drawings in which:
e) shows an embodiment of an arrow having a collapsing tail stopping mechanism;
The present invention relates to arrows having a wide variety of structures. In some embodiments, the arrows are pyrophoric. In other embodiments, the arrows are explosive. A pyrophoric arrow includes an incendiary envelope with a pyrophoric or incendiary filling contained therewithin, the incendiary envelope and the filling being consumed through a reaction upon impact. In some embodiments, either pyrophoric, or explosive, the arrows include an inventive unibody structure having an integrated stabilizing mechanism. In some embodiments, the arrows include inventive stabilizing and penetration stopping mechanisms. In all embodiments, the arrows receive kinetic energy from a delivery vehicle (bomb, rocket, missile, bullet sleeve). The arrows penetrate their intended target due to this kinetic energy. Various arrow delivery vehicles that can be used with the arrows of the present invention are well known in the art. In some embodiments, the arrow is part of a mini-rocket.
In pyrophoric or incendiary arrows, the metal oxide undergoes an exothermic reaction with the envelope (in addition with undergoing a reaction with the metal powder). The envelope is therefore referred to accordingly as being an “incendiary envelope”. Exemplary, for an Mg envelope and a copper oxide filling, the reaction may be as follows
Mg(0)+CxOy=MgO+Cu(0)
In pyrophoric arrows, the consummation of the envelope is due to the sub-stoichiometry of the filling, since the oxygen-rich filling requires more metal than available in the metal powder. The sub-stoichiometry can be calculated exactly to provide the required effect. In embodiments of a pyrophoric arrow in which the metal oxide is stoichiometric, the filling and envelope may be consumed in a reaction that occurs in an oxygen-rich environment as the arrow encounters high friction at high velocity. Such arrows may be called “incendiary arrows”. The envelope is ignited upon impact by the high velocity/high friction, O-rich conditions. These conditions lead to the reactions cited above without a need for the filling sub-stoichiometry requirement, since the oxygen rich environment requires more metal consumption than available in the filling. Incendiary filling candidates for stoichiometric fillings may include the fillings disclosed in U.S. Pat. No. 6,540,175, i.e. titanium-boron-Teflon with CTBN as the binder, titanium-boron-Teflon with VitonA as the binder, titanium-boron with ammonium perchlorate with VitonA as the binder, aluminum potassium perchlorate with VitonA as the binder and aluminum iron oxide with VitonA as the binder.
In general, the consumption of an incendiary envelope in the exothermic reaction with the filling is a key inventive feature of the pyrophoric and incendiary arrows disclosed herein. It is emphasized that in contrast with prior art incendiary arrows that use the same materials as the incendiary arrows of the present invention, in incendiary arrows of the present invention the envelope is consumed in the reaction, thereby providing a key inventive feature.
In explosive arrows, filling 108 is made of an explosive material. Exemplarily, the material may be a mixture of 93% PETN and 7% WAX. Other explosive materials that can fit the diameter and volume limitations can also be used.
An arrow of the present invention, either pyrophoric, incendiary or explosive, further includes an igniter mechanism 110, operative to ignite the pyrophorie filling or to set off the explosive filling. The igniter may consist of gunpowder encapsulated and activated by a standard bullet pica. Mechanism 110 may be positioned at either end of the pyrophoric or explosive filling inside the envelope. Such mechanisms are well known in the art, see for example the dart ignition system in U.S. Pat. No. 6,540,175 to Mayersak et al. The arrow may further include sabots 112 for positioning adjustments within the envelope and tail section. Exemplarily, the sabots may allow use of a standard bullet cartridge as a delivery vehicle for an arrow by adjusting the arrow to a standard bullet jacket 114.
Externally, the structure of arrow 100 may resemble known arrow structures, see. e.g. the flechette shanks disclosed in U.S. Pat. No. 4,922,826 to Busch et al. In same embodiments, the envelope and the stabilizing mechanism form a unibody structure.
a shows a unibody structure 200 with a hollow envelope 202 having an internal cross fin structure 204 in a first manufacturing stage. The envelope is shown with an exemplary cylindrical shape. Structure 200 can be made for example by extrusion of a long Al tube, which can then be cut to size. Exemplary Al materials may be 6061-t6, 6063-t6 and 7075-t3. The structure dimensions may vary according to the application. In some embodiments, D may be between ca. 6-25 mm and L may be between ca. 50-250 mm. Yet other diameters and lengths may be employed for other applications. More generally, the structure dimensions can be defined as having a ratio UD between ca 2-42. The dimensions cited are exemplary and not meant to be restrictive.
b shows structure 200 after removal of the internal fin structure from the entire cylinder (e.g. by drilling) except for a tail section 206.
In some embodiments, the arrow (pyrophoric or explosive) may have different stabilizing mechanisms. In one embodiment shown in
Returning now to
d shows in longitudinal cross section arrow 300 in flight (in the air), wherein an air flow lifts and pulls cup 302, bushload 310 and capsule 304 away from filling 308. Upon impact of the arrow (head) into a target, the cap, bushload and capsule are accelerated toward the filling, pushing the capsule toward the metal disk and causing the capsule content to spill (due to impact on the disk) and ignite the pyrophoric material.
It would be clear to one skilled in the art that there may be many ways to design the cup and its connection to the capsule and arrow in order to achieve the desired results set forth herein. These ways may include variations in geometry, shapes, dimensions, connecting elements and materials.
It would be clear to one skilled in the art that there may be many ways to design the cone and its connection to the capsule and arrow in order to achieve the desired results set forth herein. These ways may include variations in geometry, shapes, dimensions, connecting elements and materials.
It would be clear to one skilled in the art that there may be many ways to design the band and its connection to the capsule and arrow in order to achieve the desired results set forth herein. These ways may include variations in geometry, shapes, dimensions, connecting elements and materials.
In yet another embodiment shown in
The mini-rocket arrows may be propelled from any known system, including single tube launchers and multi-tube launchers.
All patents mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual patent was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. For example, while described in detail with respect to uses against mines and unexploded ordnance, the arrows disclosed herein are equally useful against flying projectiles, missiles or rockets.
Number | Date | Country | Kind |
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189612 | Feb 2008 | IL | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB09/50646 | 2/17/2009 | WO | 00 | 8/11/2010 |