Controlled payload release mechanism for multiple stacks of pyrophoric foils to be contained in a single decoy device cartridge

Abstract

A decoy device including: a cartridge casing; and two or more pyrophoric assemblies disposed longitudinally in the casing for sequential ejection from the casing, the two or more pyrophoric assemblies including: a pyrophoric material; a piston positioned rearward in an ejection direction relative to the pyrophoric material, the piston being movable in the ejection direction upon application of ejection force to eject the pyrophoric material from the casing; one or more energetic materials positioned rearward in an ejection direction relative to the piston, the one or more energetic materials being initiated by electrical impulse to provide the ejection force to the piston; and an inert barrier layer positioned rearward in an ejection direction relative to the impulse cartridge.

Claims

1. A decoy device comprising: a cartridge casing; and two or more pyrophoric assemblies disposed longitudinally in the casing for sequential ejection from the casing, the two or more pyrophoric assemblies comprising: a pyrophoric material; a piston positioned rearward in an ejection direction relative to the pyrophoric material, the piston being movable in the ejection direction upon application of ejection force to eject the pyrophoric material from the casing; one or more energetic materials positioned rearward in an ejection direction relative to the piston, the one or more energetic materials being initiated by electrical impulse to provide the ejection force to the piston; and an inert barrier layer positioned rearward in an ejection direction relative to the one or more energetic materials.

2. The decoy device of claim 1, further comprising a first scored diaphragm positioned between the piston and the pyrophoric material.

3. The decoy device of claim 2, further comprising a second scored diaphragm positioned between the one or more energetic materials and the inert barrier layer.

4. The decoy device of claim 1, wherein the inert barrier layer is alumina.

5. The decoy device of claim 1, further comprising wiring extending from a base of the casing to the energetic material of at least a forward most one of the two or more pyrophoric assemblies to electrically initiate the energetic material of at least the forward most one of the two or more pyrophoric assemblies.

6. The decoy device of claim 5, wherein the wiring extends from the base to the energetic material of each of the two or more pyrophoric assemblies to sequentially electrically initiate the energetic material of each of the two or more pyrophoric assemblies.

7. The decoy device of claim 5, further comprising a fuze operatively connected to the energetic material of each of the other of the two or more pyrophoric assemblies, the fuze being initiated by the electrical initiation of the energetic material of at least the forward most one of the two or more pyrophoric assemblies.

8. The decoy device of claim 1, wherein the energetic material is integrated into the piston.

9. The decoy device of claim 1, wherein the energetic material is an impulse cartridge arranged between the piston and the inert barrier layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features, aspects, and advantages of the apparatus of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

(2) FIG. 1 illustrates a decoy device showing the maximum allowable dimensions of the system.

(3) FIG. 2 illustrates the physical characteristics of another decoy device.

(4) FIG. 3 illustrates maximum dimensions of a rectangular flare casing.

(5) FIG. 4 illustrates main components of an infrared countermeasure decoy flare.

(6) FIG. 5 illustrates a two-stage nozzle discharge thruster.

(7) FIG. 6a illustrates a pre-ruptured scored metal diaphragm used in the thruster of FIG. 5.

(8) FIG. 6b illustrates the scored metal diaphragm of FIG. 5a being ruptured.

(9) FIG. 7a illustrates a cross-sectional view of a multi-stack pyrophoric foil decoy cartridge.

(10) FIG. 7b illustrates a foil stack from the detail in FIG. 7a.

(11) FIG. 8a illustrates a cross-sectional view of another embodiment of a multi-stack pyrophoric foil decoy cartridge.

(12) FIG. 8b illustrates a foil stack from the detail in FIG. 8a.

(13) FIG. 9 illustrates a modification of the multi-stack pyrophoric foil decoy cartridge of FIG. 8a.

DETAILED DESCRIPTION

(14) In the embodiments disclosed herein, and for the sake of illustration clarity, the decoys are shown with only pyrophoric foil stack assemblies. However, it will be appreciated by those having ordinary skill in the art that more stack assemblies may also be provided, however, at the cost of reducing the total payload volume.

(15) In a conventional decoy device, a one-piece cylindrical aluminum case is fitted with one single impulse cartridge to function as a power source for the ejection of countermeasure flares. When the impulse cartridge receives an electrical firing pulse from the aircraft, the build-up of expanding gases from the chemical reaction with the energetic materials forces a piston to move rapidly forward, causing the cartridge end-cap to rupture and release the stacked pyrophoric foil layers into the airstream. Such underlying concept is applied here, but with at least one additional impulse cartridge implemented and separated into discrete sub-payloads using a metal diaphragm and an alumina granules barrier layer as shown in FIG. 7a.

(16) In the decoy device 100 of FIG. 7a, a series of wires 102 connect each impulse cartridge 104 to tabs featured on the decoy cartridge base as in the current decoys for connection to the Countermeasure Dispensing System. The decoy deployment system will then be able to control the sequential ejection of pyrophoric foil stack assemblies 106 in an as-needed manner. Initiation of an impulse cartridge 104 forces the corresponding piston 114 to eject a forward corresponding pyrophoric foil stack assemblies 106 from the cartridge body 116. As shown in FIG. 7b, the presence of both a pre-scored diaphragm 108 and an inert barrier layer 110 compromising, for example, consolidated alumina granules, allows for the remaining sub-payloads 112 to stay in position and prevents sympathetic burning after ejection of each pyrophoric foil stack assembly 106.

(17) It is noted that the scored metallic diaphragms 108 serve two purposes. Firstly, they are intended to prevent dispersion of the underlying compacted alumina that is provided to prevent sympathetic ignition, and secondly, for the purpose of forming a Faraday cage for each pyrophoric foil stack assembly to keep them immune from electromagnetic waves (EMI and EMP), as required for Hazard from Electromagnetic Radiation to Ordnance (HERO) safety.

(18) As can be seen in the blow-up view of FIG. 7b, each pyrophoric foil stack 106 is provided with an alumina thermal barrier layer 110, metal diaphragms 108, an impulse cartridge 104, and a piston 114 for ejecting the pyrophoric foil stack 106 upon impulse cartridge initiation. The provided wiring 102 connects each impulse cartridge 104 to an appropriate tab on the decoy cartridge base 118 for contact with the mating tabs of the Countermeasure Dispensing System.

(19) In another embodiment 140, and to increase the available pyrophoric foil stack (payload) volume for each stack assembly, the impulse cartridges 104 of the concept of FIGS. 7a and 7b are replaced by piston integrated ejection charges, which are intended to be similarly ignited by electric matches as shown in FIG. 8a. The significant amount of increase in the volume of the pyrophoric foil stacks should significantly increase the effectiveness of the decoy system by emitting the intense IR spectrum over a larger volume of space.

(20) As can be seen in FIG. 8a and its blow-out view of FIG. 8b, each discrete pyrophoric foil stack 106 is provided with energetic materials (ejection or impulse charges) 150 that are confined within a crimped housing cartridge situated in the concavity of a piston 114. Similar to the concept of FIGS. 7a and 7b, the ejection charges 150 are initiated electrically by the powering of the provided electric matches for sequential ejection of pyrophoric foil stack assemblies 106 in an as-needed manner.

(21) A cross-sectional view of the second embodiment with ejection charge integrated pistons is provided in FIG. 8a. As can be seen in the blow-up view of FIG. 8b, the energetic material (ejection charge) 150 is contained within a crimped housing cartridge underneath the piston 114. Each pyrophoric foil stack assembly is provided with inert (alumina) layer 110, diaphragms 108, a piston 114 with integrated ejection charge assembly 150, pyrophoric foil stack 106 (payload), and the necessary wiring 102 that connects each ejection charge electric match to an appropriate tab on the decoy cartridge base 118 for contact with the mating tabs of the countermeasure dispensing system.

(22) A modification of the multi-stack pyrophoric foil decoy cartridge 140 of FIGS. 8a and 8b, is shown in FIG. 9 and generally referred to by reference number 160. In this modification, the first (forward in a direction of ejection) pyrophoric foil stack 106 assembly is ejected as was described for the concept of FIGS. 7a and 7b. However, the ejection charges of the subsequent (rearward) pyrophoric foil stack 106 assemblies are sequentially initiated by the provided time-delay fuse strips 170. In this modification, the ejection (impulse) charges of the first (forward) pyrophoric foil stack 106 assembly is designed to also ignite the time-delay fuse strip, which would then sequentially ignite ejection charges of the remaining pyrophoric foil stack 106 assemblies. It is appreciated that such time-delay fuse strips can be designed to burn at rates that are in millisecond per inch to those that are in tens of seconds per inch. This modification has the advantage of being simpler in design and only requires a single dispensation command.

(23) It is also noted that a similar modification can be made to the multi-stack pyrophoric foil decoy cartridge concept of FIGS. 7a and 7b, however, additional pyrotechnic charges may be provided so that the flame from the first impulse cartridge could ignite the fuse strip.

(24) In addition to the above embodiments, the following modifications may also be made. In these modifications, all pyrophoric foil stack assemblies are dispensed simultaneously by a single impulse cartridge or piston integrated charge from the decoy device cartridge and would subsequently release their pyrophoric materials in a controlled timely fashion as the collection of pyrophoric foil stack assemblies freefall in the airstream.

(25) The modifications may require:

(26) Each pyrophoric foil stack assembly to be protected in a separate sealed compartment;

(27) The added packaging requirement may reduce the available volume of pyrophoric foil stacks (payload);

(28) Unless a time-delay fuse is employed, each pyrophoric foil stack assembly may be provided with a separate means of ignition such as an electrical energy source (capacitor or battery) and if the timing must be programmable, there may be a need for appropriate onboard circuitry and electronics; and

(29) Due to the free-fall nature of the released pyrophoric foil stack assemblies, the available range of time between the pyrophoric foil stack releases may be limited.

(30) Although the embodiments discussed above are particularly well suited to multi-stack pyrophoric foil decoy cartridges for military aircraft, they can also be applied to countermeasure flares used in commercial non-military applications. Although, countermeasure flares have previously been used in only military applications for defensive countermeasures, the same now have widespread application in commercial applications for signaling and illumination. However, as the world grows more dangerous, more commercial companies are relying on countermeasure flares for defensive countermeasure to protect their assets, such as airline and cruise ship vessels.

(31) While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.