Infra-red emitting decoy flare

Abstract

An infra-red emitting decoy flare capable of diverting an incoming missile equipped with a counter-countermeasures system away from an intended target consisting of a primer flare ( 2 ), a spectral flare ( 4 ) and a means for igniting the primer flare ( 22, 30 ), all contained within a flare casing ( 6 ). The primer flare ( 2 ) is formed from a fast burning pyrotechnic composition and is adapted to produce an intense infra-red source of short duration on ignition. The spectral flare ( 4 ) is ignited by the burning of the primer flare ( 2 ) and is adapted to produce a slower burning composition having a fixed ratio in the intensity of infra-red radiation emitted, when burning, in at least two fixed bands.

1 . An infra-red emitting decoy flare comprising a flare casing ( 6 ), two pyrotechnic components housed within the flare casing and an ignition means ( 30 ) for igniting the pyrotechnic components characterised in that the two pyrotechnic components comprise a primer flare ( 2 ;  50 ) and a spectral flare ( 4 ) wherein the primer flare ( 2 ;  50 ) consists of at least one primer pellet ( 8 ;  42 ;  52 ), each primer pellet being composed of a fast burning pyrotechnic composition and being adapted such that, in use, ignition of one primer pellet causes rapid ignition of all the primer pellets to produce an intense infra-red source, wherein the spectral flare ( 4 ) consists of at least one spectral pellet ( 10 ), each spectral pellet being of a pyrotechnic composition adapted such that, in use, ignition of the spectral pellets produces a spectral infra-red source wherein the ratio of the intensity of the infra-red spectrum at at least two fixed bands is within a fixed range, and wherein the primer flare ( 2 ;  50 ) and spectral flare ( 4 ) are adapted such that, in use, the spectral flare ( 4 ) is still burning after the primer flare ( 2 ;  50 ) has finished burning.  
     
     
         2 . An infra-red emitting decoy flare as claimed in  claim 1  wherein the spectral flare ( 4 ) is adapted such that the intensity of the infra-red radiation emitted, in use, is greater than that normally emitted from an intended target.  
     
     
         3 . An infra-red emitting decoy flare as claimed in  claim 1  or  claim 2  wherein the primer flare ( 2 ) comprises a stack of discs ( 8 ) of a pyrotechnic composition.  
     
     
         4 . An infra-red emitting decoy flare as claimed in any preceding claim wherein the primer flare ( 2 ) is provided with a central hole ( 12 ).  
     
     
         5 . An infra-red emitting decoy flare as claimed in any of the preceding claims wherein the primer flare ( 2 ) is provided with a plurality of holes ( 44 ).  
     
     
         6 . An infra-red emitting decoy flare as claimed in any of  claims 1  to  4  wherein the primer flare ( 50 ) has a plurality of grooves ( 54 ) in its surface.  
     
     
         7 . An infra-red emitting decoy flare as claimed in any preceding claim wherein the burn time of the primer flare ( 2 ;  50 ) is within the range of 100 to 600 ms.  
     
     
         8 . An infra-red emitting decoy flare as claimed in  claim 7  wherein the burn time of the primer flare ( 2 ;  50 ) is in the range of 150 to 250 ms.  
     
     
         9 . An infra-red emitting decoy flare as claimed in any preceding claim wherein the spectral flare ( 4 ) comprises a single pellet ( 10 ).  
     
     
         10 . An infra-red emitting decoy flare as claimed in  claim 9  wherein the spectral flare ( 4 ) is provided with a central hole ( 14 ).  
     
     
         11 . An infra-red emitting decoy flare as claimed in any preceding claim wherein the spectral flare ( 4 ) and primer flare ( 2 ;  50 ) are adapted such that, in use, the spectral flare is ignited by the burning of the primer flare  
     
     
         12 . An infra-red emitting decoy flare as claimed in any preceding claim wherein the primer flare ( 2 ;  50 ) is formed from a fast burning magnesium-Teflon-Viton composition.  
     
     
         13 . An infra-red emitting decoy flare as claimed in any of claims  1 - 11  wherein the primer flare ( 2 ;  50 ) is formed from a pyrotechnic composition adapted such that, in use, ignition of the primer pellet produces an intense spectral infra-red source wherein the ratio of the intensity of the infra-red spectrum at at least two fixed bands is within a fixed range.  
     
     
         14 . An infra-red emitting decoy flare as claimed in  claim 13  wherein the primer flare ( 2 ;  50 ) is comprised from a composition of potassium benzoate, potassium perchlorate and a binder chosen from the group of RDX, HMX or HNS.  
     
     
         15 . An infra-red emitting decoy flare as claimed in any preceding claim wherein the spectral flare ( 4 ) is formed from a pyrotechnic composition which produces quantities of gas on ignition.  
     
     
         16 . An infra-red emitting decoy flare as claimed in any preceding claim wherein the spectral flare ( 4 ) is formed from a composition having an organic fuel, an oxidant and a binder.  
     
     
         17 . An infra-red emitting decoy flare as claimed in  claim 16  wherein the organic fuel is chosen from the group comprising sucrose, lactose, starch and potassium benzoate.  
     
     
         18 . An infra-red emitting decoy flare as claimed in any of  claims 1  to  15  wherein the spectral flare ( 4 ) is formed from a composition having a boron fuel, an oxidant and a binder.  
     
     
         19 . An infra-red emitting decoy flare as claimed in any of claims  16 - 18  wherein the oxidant is chosen from the group of potassium perchlorate, potassium nitrate, sodium nitrate and ammonium nitrate.  
     
     
         20 . An infra-red emitting decoy flare as claimed in any of claims  16 - 19  wherein the binder is chosen from the group of Viton A, dextrin or polybutyl rubber.  
     
     
         21 . An infra-red emitting decoy flare as claimed in any of claims  16 - 19  wherein the binder is an explosive material having a waxy composition.  
     
     
         22 . An infra-red emitting decoy flare as claimed in  claim 21  wherein the binder is chosen from the group of RDX, IMX and HNS.  
     
     
         23 . An infra-red emitting decoy flare as claimed in  claim 1  wherein the spectral flare composition ( 4 ) is formed from a mix of 30-40% by mass of potassium benzoate and 60-70% by mass of potassium perchlorate together with 3-8% by mass of Viton A, RDX, HMX or HNS.  
     
     
         24 . An infra-red emitting decoy flare as claimed in  claim 1  wherein the spectral flare composition ( 4 ) is formed from a mix of 30% by mass of boron and 70% by mass of potassium nitrate together with a Viton A binder.  
     
     
         25 . An infra-red emitting decoy flare as claimed in any of  claim 18  wherein the spectral flare composition ( 4 ) comprises an additive such as silicon.  
     
     
         26 . An infra-red emitting decoy flare as claimed in  claim 25  wherein the spectral flare composition ( 4 ) is formed from a mix of 20% by mass of boron, 10% by mass of silicon and 70% by mass of potassium nitrate together with a Viton A binder.