US3861311A

US3861311A - Plastic semi armor piercing incendiary projectile

Info

Publication number: US3861311A
Application number: US379023A
Authority: US
Inventors: Stephen J Bilsbury
Original assignee: US Air Force
Current assignee: US Air Force
Priority date: 1973-07-13
Filing date: 1973-07-13
Publication date: 1975-01-21
Anticipated expiration: 1992-01-21

Abstract

A semi armor piercing incendiary projectile having an ogival pointed penetrator head with an elongated cylindrical tail portion of reduced diameter extending behind for slidably engaging a mischmetal core having a central hole therethrough. A plastic jacket with an integral rotating band of the same material surrounds the projectile and a steel pusher plate is positioned at the base of the core which is then covered by a plastic end cap.

Description

Bilsbury 51 Jan. 21, 1975 PLASTIC SEMI ARMOR lPIERCING INCENDIARY PROJECTILE [75] Inventor: Stephen J. Bilsbury, Shalimar, Fla.

[22] Filed: July 13, I973 [21] Appl. No.: 379,023

[52] U.S. Cl 102/52, 102/90, l02/92.2

[51] Int. Cl. F42b 11/14, F42b 13/04 [58] Field of Search 102/6, 66, 90, 38, 52, 102/92.1-92.7, 93

[56] References Cited UNITED STATES PATENTS 2,475,632 7/1949 Moore et a1. 102/90 2,532,323 12/1950 Miller, Jr. 102/90 3,242,865 3/1966 Jungermann et al. 102/92.7

3,302,570 2/1967 Marquardt 102/52 3,439,619 4/1969 Bock et al l02/92.7

3,463,047 8/1969 Germershausen 102/92.7 X 3,566,793 3/1971 Kruzell [02/923 X 3,645,208 2/1972 Weinssen et al 102/90 X FOREIGN PATENTS OR APPLICATIONS 633,321 6/1963 Belgium 102/927 Primary Examiner-Samuel Feinberg Assistant Examiner-H. J. Tudor Attorney, Agent, or Firm-Harry A. Herbert, .Ir.; Arsen Tashjian [57] ABSTRACT A semi armor piercing incendiary projectile having an ogival pointed penetrator head with an elongated cylindrical tail portion of reduced diameter extending behind for slidably engaging a mischmetal core having a central hole therethrough. A plastic jacket with an integral rotating band of the same material surrounds the projectile and a steel pusher plate is positioned at the base of the core which is then covered by a plastic end cap.

7 Claims, 1 Drawing Figure PLASTIC SEMI ARMOR PIERCING INCENDIARY PROJECTILE BACKGROUND OF THE INVENTION This invention relates to a semi armor piercing projectile and more particularly, the invention is concerned with providing a fully plastic exterior incendiary projectile with rotating band and base made of the same plastic and having a steel penetrator with a mischmetal body fitting over the tail portion of the penetrator.

Heretofore, the standard design for metal-piercing ammunition includes a hardened steel penetrator encased by a soft metal jacket to prevent damage to the rifling in the base of the weapon as the ammunition is discharged. The jacket is usually composed of a soft metal called gilding metal while the nose or piercing end is steel or some other hard metal. The jacket also operates as a windshield by reducing aerodynamic drag to thereby control the amount of energy lost between the nozzle of the gun and the target.

In an attempt to increase the damage at the target, some presently known projectile designs include an incendiary material forward of the penetrator enclosed in the windshield. This arrangement produces an incendiary flash outside the armored target prior to penetration by the projectile thereby substantially destroying its effectiveness against targets such as aircraft fuel tanks and fuel storage facilities. Some other presently known projectiles which position the incendiary material at the base of penetrator include a metallic windshield which can fail to rupture on impact thus making the incendiary material completely ineffective. Thus, it would be especially advantageous to provide a metalpiercing incendiary projectile which includes a skin that would rupture easily on impact thereby causing the incendiary material to break up and be exposed so that it could burn in the target area after penetration. Also, the projectile should be easy and economical to manufacture as well as having minimum friction characteristics so as not to cause excessive gun barrel wear.

SUMMARY OF THE INVENTION The present invention is concerned with providing a semi armor piercing incendiary projectile having an injection molded jacket and rotating band and base made of a thermoplastic so that the exterior of the two projectile is completely made of plastic. An ogival pointed penetrator head with an elongated cylindrical tail portion of reduced diameter extending behind for slidably engaging a mischmetal core is enclosed in the plastic skin which ruptures on impact with the target allowing the penetrator and exposed mischmetal to enter and break up in the target area.

Accordingly, it is an object of the invention to provide an improved incendiary projectile capable of piercing metal and breaking up from available kinetic energy so that it becomes pyrophoric on impact.

Another object of the invention is to provide an improved incendiary projectile having a plastic jacket which easily ruptures on impact to expose the pyrophoric metal underneath.

Still another object of the invention is to provide a semi armor piercing incendiary projectile which substantially reduces gun barrel deterioration due to interaction between the copper rotating band and the gun barrel by making the rotating band of the same thermoplastic material which covers the remainder of the projectile.

A further object of the invention is to provide an improved projectile wherein the moment of inertia, weight, and center of gravity are easily altered to fit any special ballistic requirements.

A still further object of the invention is to provide an improved incendiary projectile having ease and economy of manufacture using non-strategic materials and processes and being capable of modern mass production techniques.

These and other objects features and advantages will become more apparent after considering the following description taken in conjunction with the annexed drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a view in longitudinal cross section of the plastic jacket with the internal elements of the incendiary projectile shown in their relative positions according to the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawing, there is shown a jacket 13 having an enlarged outwardly extending portion 15 which serves as a rotating band for the projectile. The jacket 13 and the integral rotating band 15 are preferably made of thermoplastic material such as polyethylene, glass filled nylon or hard polyvinyl chloride. The use of these materials having different specific weights makes it possible to easily alter the moment of inertia, weight and center of gravity of the projectile by selecting the volume and dimensions of the jacket 13 and correspondingly matching the proportions thereof to the overall volume and dimension of the projectile to match it to specific ballistic requirements.

A penetrating head 17 is disposed in the forward end of the jacket 13 and includes a cylindrical rod-like tail portion 19 extending rearwardly. The penetrating head 17 is preferably made of steel or some other equally hard metal so as to easily penetrate the target. An incendiary material core 21 made of mischmetal, for example, includes a central elongated opening which is dimensioned to slide over the rod-like cylindrical tail portion 19 of the penetrator 17. The outside dimension of the core 21 is completely covered by the jacket 13 and fits against the shoulder 23 on the penetrator 17. A steel pusher plate 25 is positioned against the rearward end of the mischmetal core 21 and includes the projection 27 which fits into the central opening in the core 21 and against the rearward end of the tail 19. An end cap 29 of plastic is then ultrasonically welded to the open base of the plastic jacket 13 to complete the assembly of the incendiary projectile.

When the projectile is fired against the target which may be a container of fuel or an aircraft fuel tank, the plastic jacket 13 ruptures on impact allowing the penetrator 17 to pierce the protective metal plates and wall of the target container. The available kinetic energy causes the mischmetal rare earth alloy incendiary ma terial 21 which is immediately behind the penetrator 17 to fracture into lethal particles so as to become pyrophoric on impact. The plastic jacket 13 ruptures more easily than a metal jacket thus exposing the pyrophoric metal 21 underneath and in addition has the advantages of being lower in cost and causing less wear in the weapon barrel.

The improved plastic semi armor piercing incendiary projectile according to the invention is provided with the thermoplastic jacket 12 which also serves as a windshield to reduce aerodynamic drag of the projectile and thus minimize energy loss during flight to the target. A rotating band 15 of plastic encirles the jacket 13 and is integral therewithfor engaging the rifling in the gun bore thereby significantly reducing the friction of the projectile body as it is forced through the gun bore while greatly improving the efficiency of the weapon operation.

It is thus seen that a projectile has been described which is simple in operation and easily manufactured as well as extremely effective in penetrating metal' walled containers with flammable fluids therein. These features are accomplished without producing undue wear or causing damage to the gun bore as the projectile passes therethrough. In an example of the results obtainable with the incendiary projectile according to the invention, a mm round fired at 2,400 feet per second through a one-half inch steel plate into a 55 gallon drum half filled with diesel fuel causes the fuel to ignite. In operational use in high performance aircraft, the hereinbefore described projectile would serve to reduce gun barrel erosion and heating and to reduce the use of critical material (copper) while at the same time providing a highly effective anti-aircraft incendiary projectile.

Although'the invention has been illustrated in the accompanying drawings and described in the foregoing specification in terms of a preferred embodiment thereof, the invention is not limited to this embodiment or to the preferred configuration mentioned. It will be apparent to those skilled in the art that my invention could have extensive use in other operations where it is desirable to provide an incendiary projectile which is highly effective against armor protected fuel storage tanks while being capable of easy modification of the ballistic properties of the projectile by altering the movement of inertia, weight and center of gravity.

Having thus set forth the nature of my invention, what 1 claim and desire to secure by Letters Patent of the United States is:

1. A plastic semi-armor piercing incendiary projectile for firing through a weapon having a rifled bore comprising a penetrating head having a ogival shaped head portion with a rod-like cylindrical tail portion of reduced diameter extending rearwardly therefrom, a flat shoulder forming the rearward surface of said head portion, a cylindrical core of incendiary material having a clearance opening through the central axis thereof, the opening in said cylindrical core being dimensioned to fit over the rod-like tail portion of said penetrating head and against the shoulder thereon, a steel pusher plate positioned against the rearward end of said incendiary core, said pusher plate including a short rod-like projection extending forwardly therefrom for insertion through the rearward end of the opening in said cylindrical core against the rearward end of the rod-like tail portion of said penetrating head, a one-piece plastic jacket having an open rearward end being dimensioned to completely enclose said penetrating head with said incendiary core and steel pusher plate attached thereto, said plastic jacket including an integral rotating band disposed therearound near the rearward end thereof and a plastic end cap ultrasonically welded to the open rearward end of said plastic jacket against the rearward surface of said pusher plate, said plastic jacket rupturing on impact with a target to expose the penetrating head which pierces any protective armor in the target area allowing the incendiary core to penetrate the target and break up by available kinetic energy into lethal particles causing fire to start in the presence of flammable material.

2. The plastic semi-armor piercing incendiary projectile defined in claim 1 wherein said cylindrical core of incendiary material is fabricated of mischmetal alloy.

3. The plastic semi-armor piercing incendiary projectile defined in claim 2 wherein said penetrating head is constructed of hardened steel.

4. The plastic semi-armor piercing incendiary projectile defined in claim 2 wherein said penetrating head is constructed of tungsten carbide.

5. The plastic semi-armor piercing incendiary projectile defined in claim 2 wherein said one-piece plastic jacket is fabricated of a thermoplastic material, said thermoplastic material being polyethylene.

6. The plastic semi-armor piercing incendiary projectile defined in claim 2 wherein said one-piece plastic jacket is fabricated of a thermoplastic material, said thermoplastic material being glass filled nylon.

7. The plastic semi-armor piercing incendiary projectile defined in claim 2 wherein said one-piece plastic jacket is fabricated of a thermoplastic material, said thermoplastic material being hard polyvinyl chloride.

Claims

1. A plastic semi-armor piercing incendiary projectile for firing through a weapon having a rifled bore comprising a penetrating head having a ogival shaped head portion with a rodlike cylindrical tail portion of reduced diameter extending rearwardly therefrom, a flat shoulder forming the rearward surface of said head portion, a cylindrical core of incendiary material having a clearance opening through the central axis thereof, the opening in said cylindrical core being dimensioned to fit over the rod-like tail portion of said penetrating head and against the shoulder thereon, a steel pusher plate positioned against the rearward end of said incendiary core, said pusher plate including a short rod-like projection extending forwardly therefrom for insertion through the rearward end of the opening in said cylindrical core against the rearward end of the rod-like tail portion of said penetrating head, a one-piece plastic jacket having an open rearward end being dimensioned to completely enclose said penetrating head with said incendiary core and steel pusher plate attached thereto, said plastic jacket including an integral rotating band disposed therearound near the rearward end thereof and a plastic end cap ultrasonically welded to the open rearward end of said plastic jacket against the rearward surface of said pusher plate, said plastic jacket rupturing on impact with a target to expose the penetrating head which pierces any protective armor in the target area allowing the incendiary core to penetrate the target and break up by available kinetic energy into lethal particles causing fire to start in the presence of flammable material.