Incendiary projectile.

Application filed April 10, 1919. Serial No. 289.176.

To dllrlom it may concern:

Be it known that I, Claude Theodore James Vautin, a subject of the King of England, residing at London, England, have 5 invented certain new and useful Improvements in Incendiary Projectiles, of which the following is a specification.

This invention relates to incendiary projectiles, in particular such as are intended 10 for use in trench-guns or hand-grenades.

Heretofore it has been customary to inclose the incendiary or metallothennic material of such projectiles within an outer casing or shell, usually of steel but sqme15 times of softer material as in a cartridge case, and to provide the projectile with both an igniting and a bursting charge, the former of which served to ignite the incendiary material, and the latter of which served to 20 burst the said shell and scatter the said material. Sometimes a double-purpose charge that both ignites the incendiary material and bursts the shell or other containing case has been employed. One result of such con25 structions was that the incendiary material was necessarily scattered with considerable force, owing to the force required to burst the containing vessel or shell, and the incendiary material was consequently subdi30 vided by the burst more finely than was altogether desirable.

I have found that the incendiary material is better distributed after it has been ignited if it be not contained in a container or cas35 ing which is thus to be opened by a disruptive force.

For the purpose of obtaining this improved distribution of the ignited incendiary material, the present invention provides a 40 projectile whose body, or an outer shell thereof, is formed wholly or in part of an ignitible substance that is hard when cold, but becomes soft and fluid when ignited, for example a metallic mixture hardened by 45 mechanical pressure. Such an ignitible substance may be a metallic mixture which comprises a combustible binding material or is rendered hard by incorporation with such a binding material. The said ighitible sub50 stance preferably comprises as the binding material either sulfur or sulfur together with a metallic sulfid decomposable by the metal of the mixture.

The projectile provided by'this invention may be prepared so as to be suitable for use 55 in a trench-gun or the like, or as a handgrenade.

Two embodiments of the invention are illustrated by way of example in the accompanying drawing, wherein— 60

Figure 1 is a vertical sectional elevation showing a projectile according to the invention adapted for use in a Stokes gun, and

Fig. 2 is a like view of a hand-grenade according to the invention. . 65

Fig. 3 is a vertical sectional elevation of a modified form of the present invention.

Referring first to Fig. 1, the projectile comprises a head A and a base B of steel, the former being a disk having a central ap- 70 erture A¹, and the latter being in the form of a disk with a central tail-piece or stem B¹which is hollow.’ The aperture in the head is screw threaded to receive the ordinary fuse C for igniting the mixture, and the tail- 78 piece B¹ of the base is arranged to receive the usual propellant charge , and is perforated as shown at B², so that the gases liberated by the charge when fired, can escape into the chamber of the gun. The outside 80 diameters of the base and head are such as to fit the bore of the gun.

Two or more steel rods D are prepared which may have shoulders D¹ at each end, and are of such a length between the shoul- 85 ders that, when the rods are inserted between the said head and base with their ends passing into holes prepared to receive them in the head and base, respectively, the latter will be spaced apart the distance requisite 90 to give the projectile its desired length. The ends of the rods D are screw threaded and pass, as above stated, through holes in the head and base and receive nuts D² on their projecting ends so as to hold the head and' 95 base firmly together at a predetermined distance apart. Alternatively, the rods may be secured in the base otherwise than by shoulders and nuts, for instance by being screwed into the said base so that the outside thereof ¹⁰⁰shall be free from nuts or projecting ends of rods.

A mixture consisting of aluminium. pow-. der and stilfur, both in a finely - divided condition and in such proportions that sub- 10^r> stantially. the whole of the sulfur can be taken up by the metal to form a stilfld therewith is made/ 1- part of this’ mixture is iii-1,316,006 corporated with 2 parts of an alumino-thermic mixture or of what is ordinarily known as thermalloy (a mixture of powdered aluminium containing zinc'with ferrosofer5 ric oxid, in such proportions that the aluminium powder will be entirely oxidized and the iron entirely reduced by the interchange between, them of oxygen).

The above-stated ingredients are inti10 mately mixed together, and then heated to a temperature not exceeding 200° C. with constant stirring, until a plastic material is obtained. This material is then cast on to the frame comprising the base B and head 15 A united by the two or more steel rods D in such a way that a cylindrical block E of the material, cored out at E¹ to provide a chamber for a detonator, fills the space betweenthe head and base and constitutes the 20 body of the projectile. It will be appreciated that the material is thus cast around the said two rods so that the result constitutes a substantially solid unit.

In use, the fuse C is inserted in the head 25 and the propelling charge in the stem B¹of the base with the result that when it is fired and the fuse is also fired, by impari-. or otherwise, the whole body E of the projectile ignites and forms a liquid slag of great 30 fluidity together with molten iron, and this slag and iron is scattered by the shock of impact or gravity and in a more desirable manner than if it were scattered by an explosive charge.

As an example of an alternative to the above sulfurous mixture a metallic sulfid such as can be decomposed by the metal constituent of the thermalloy or other aluminothennic mixture may be employed, this sul40 fid being ground to a fine powder and mixed with finely divided sulfur equivalent to from 15%-50% by weight of the sulfid. In this case the metallic sulfid, such as iron pyrites, after having been finely ground is mixed 45 with say from 15%—50% of its weight of sulfur, and this mixture is heated with constant stirring until the mass becomes fluid. It is then cast and allowed to cool and set hard. This bard product is finely ground 50 and added in the desired proportion to the alumino-thermic mixture . and the \ mass heated., as above directed for the mixture of sulfur and aluminium with thermalloy. The proportion of aluminium or other reducing 55 metal or alloy is, however, so chosen that the said metal will suffice to combine both with the sulfur of the metallic sulfid and with the free sulfur added thereto.

A modified form of projectile according 00 to the invention comprises a central perforated iron'tube T screwed at one end into the aperture in the head plate and secured at the other end to the base plate having a flash-hole O in the center thereof communi** eating with the interior of the tube. The former end of the tube may be closed by a screw plug or by an ordinary fuse, and the tube itself is wholly or partially filled with the ignitible mixture which surrounds the tube between the two plates. 70

Referring now to Fig. 2, the body E¹ of the hand-grenade having the form of an oblate spheroid is composed of the same ma- . terial as the body of the projectile described above with reference to Fig. 1, and is cast 75 about a core to provide, an axially disposed detonator-chamber E’ which is closed at one end and is screw-threaded at the other,· as shown at E⁴, to receive the fuse.

Whereas, in the construction described 80 above with reference to Fig. 1, the projectile may be said to be devoid of a metal-ca-sing -or shell, it is to be understood that it may be partly inclosed in such a easing. - Thus, . for example, the head A and the base B may 85 each be provided with a cylindrical flange directed toward the opposite end of the projectile but only of such axial length as will leave in the center of the projectile a band of the body-portion exposed to the air and 30 not encircled by a metallic casing. Furthermore, it is within the scope of this invention to construct a projectile substantially as a hollow body whose wall or casing is formed wholly or in part of one kind <5 95 a hard ignitible metallic mixture such as is exemplified above, and to fill the said casing with another kind of incendiary metallothermic material, such for example as one not containing free sulfur. Or again, such 100 a hollow casing may be left unfilled. In addition, instead of heating the above-mentioned mixed ingredients to form a plastic mass which is then cast into the desired shape, the mixed ingredients may be molded 105 under pressure to the desired form without the application of heat, without departing from tiie scope of the invention.