Abstract:
A family of gun propellants formulated with triaminoguanidine ethylenedinitramine (TAGED), as an oxidizer, to reduce the isochoric flame temperature while providing high mass impetus.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to gun propellants and is particularly directed to gun propellant formulations employing triaminoguanidine ethylenedinitramine as an oxidizer, to provide low isochoric flame temperatures and high mass impetus. 
     2. Prior Art 
     For several hundred years, investigators have been seeking to improve firearms and the propellants used in them. Many significant improvements have been made. However, as long as there is a demand for such weapons, the search for improvements will continue. In recent years, automatic guns have been developed which are capable of firing several thousand rounds of ammunition per minute. However, the gun propellants available heretofore have had isochoric flame temperatures in the range of 2400°K to 3300°K. As a result, the barrels of the automatic guns have tended to overheat and become warped quite rapidly. Consequently, it has been necessary to replace the gun barrels frequently, which reduces the effectiveness of such guns and adds considerably to the expense of operating such guns. While some prior art gun propellants are known which have lower flame temperatures, these cool-burning propellants generally also have significantly lower mass impetus. 
     BRIEF SUMMARY AND OBJECTS OF INVENTION 
     These disadvantages of the prior art are overcome with the present invention and a family of gun propellants is proposed which provides isochoric flame temperatures 20 to 30 percent lower than those of conventional military propellants, while yielding comparable or higher mass impetus. 
     The advantages of the present invention are preferably attained by providing gun propellant formulations employing triaminoguanidine ethylenedinitramine (TAGED) as an oxidizer. 
     Accordingly, it is an object of the present invention to provide improved gun propellants. 
     Another object of the present invention is to provide gun propellants having flame temperatures which are significantly lower than those of conventional military propellants, while yielding comparable or greater mass impetus. 
     A specific object of the present invention is to provide gun propellant formulations employing TAGED as an oxidizer. 
     These and other objects and features of the present invention will be apparent from the following detailed description. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In that form of the present invention chosen for purposes of illustration, a family of gun propellants is formulated, employing TAGED as an oxidizer, to provide flame temperatures which are significantly lower than those of conventional military propellants, while yielding comparable or greater mass impetus. 
     The theoretical performances of standard military propellants, as described in U.S. Army Propellant Manual No. AMCP-706-150, published February 1965, are shown in Table I. 
     
                       TABLE I______________________________________    Mass Impetus Flame       MolecularPropellant    ft.-lb./lb.  Temperature Weight______________________________________M-1      305,000      2417°K                             22.06M-2      360,000      3319°K                             25.64M-10     339,000      3000°K                             24.58IMR      325,000      2827°K                             24.17______________________________________ 
    
     In contrast, propellants formulated with TAGED have yielded mass impetus in the range of 330,000 to 350,000, with flame temperatures in the range of 2100°K to 2300°K. 
    
    
     EXAMPLE I 
     In accordance with the present invention, a gun propellant was formulated consisting of 75% by weight of TAGED, 24.5% by weight of nitrocellulose, and 0.5% by weight of ethyl centralite. This propellant was fired in a 20 mm Mann gun and yielded the data shown in Table II. 
     
                       TABLE II______________________________________Charge Weight      11.01 gramsGrain Dimensions (inches)              0.375 × 0.115 × 0.020Peak Pressure      35,300 psiMuzzle Velocity    1,740 ft./sec.Velocity Efficiency              90.5%Isochoric Flame Temperature              2123°KMolecular Weight   17.78Specific Impulse   332,000 ft.-lbs./lb.______________________________________ 
    
     EXAMPLE II 
     A gun propellant was formulated consisting of 55% by weight of TAGED, 20% by weight of cyclotetramethylene tetranitramine, 10% by weight of ethyl cellulose, and 15% by weight of trimetholethane trinitrate. This propellant yielded an isochoric flame temperature of 2118°K, a mass impetus of 331,200 ft.-lb/lb., and a molecular weight of 17.78. After seven days&#39; storage at 75°C, no degratation of the propellant was observed. 
     EXAMPLE III 
     A gun propellant was formulated consisting of 65% by weight of TAGED, 10% by weight of cyclotetramethylene tetranitramine, 24.5% by weight of nitrocellulose, and 0.5% by weight of ethyl centralite. This yielded an isochoric flame temperature of 2273°K, a mass impetus of 349,200 ft.lb./lbs., and a molecular weight of 18.09. 
     EXAMPLE IV 
     A gun propellant was formulated consisting of 58.5% by weight of TAGED, 21.5% by weight of cyclotetramethylene tetranitramine, 17.5% by weight of nitrocellulose, and 2.5% by weight of isodecyl pelargonate. This propellant yielded an isochoric flame temperature of 2264°K, a mass impetus of 350,600 ft.-lbs./lb., and a molecular weight of 17.97. 
     EXAMPLE V 
     A gun propellant was formulated consisting of 40.0% by weight of TAGED, 37.5% by weight of cyclotetramethylene tetranitramine, 12.5% by weight of nitrocellulose, 4.0% by weight of isodecyl pelargonate, and 6.0% by weight of ethyl cellulose. This propellant yielded an isochoric flame temperature of 2214°K, a mass impetus of 338,700 ft.-lbs./lb., and a molecular weight of 18.18. 
     A technique for producing TAGED is disclosed in the Journal of Organic Chemistry, Volume 32, p.289 (1967). Obviously, numerous variations and modifications may be made without departing from the present invention. Accordingly, it should be clearly understood that the forms of the present invention described above are illustrative only and are not intended to limit the scope of the present invention.