US2975710A - Projectile - Google Patents

Description

March 21, 1961 E. w. READ 2, 5,710

PROJECTILE Filed Nov. 1a, 1958 INVENTOR. E LLIS W. READ 19% g g-4 QJLQ/VA MQ I- ATTORNEYS= PROJECTILE Ellis W. Read, Philadelphia, Pa., assignor to the United States of America as represented by the Secretary of the Army Filed Nov. 18, 1958, Ser. No. 774,787

6 Claims. (Cl. 10266) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

The invention is a continuation-impart of my co-pending patent application, Serial No. 655,450, filed April 26, 1957, now abandoned, and relates to jacket-clad, armorpiercing projectiles of the incendiary type. More particularly, this invention relates to enhancing the uniformity of sensitivity and performance, at long ranges, when the projectile has lost a substantial part of its original velocity, and wide angles of impact, of jacket-clad, armorpiercing projectiles which are designed to act against thinwalled targets, such as gasoline tanks.

The art, in the U.S. patent application of Thomas Q. Ciccone, Serial No. 720,802, filed March 11, 1958, now Patent 2,900,914 dated August 25, 1959 for Incendiary Projectile, by maintaining closely a controlled space and geometry, teaches a means of obtaining long-range senstivity in projectiles other than jacket-clad projectiles.

However, the teachings of Ciccone could not be employed in jacket-clad projectiles. Primarily this is so because as a jacket is formed over the rear end of the solid penetrator of an armor-piercing projectile, it has a tendency to stretch throughout its length and thus distort the close dimensions which must be maintained to insure uniform sensitivity, the nose portion of the projectile, which houses a preformed impact sensitive mixture, must maintain its dimensions to close tolerances since this mixture functions as a result of crystal shear.

I have overcome the above difficulty by providing a jacket-clad projectile with an inner jacket in the nose fabricated from a substantially harder material than the outer jacket, and providing a construction in which the contours of both jackets are matched and placed in tightfitting contact over a portion of the projectile amounting to approximately 30% of the length of the entire projectile. Now when the rear end of the outer jacket is being spun over the rear end of the solid penetrator, the tightfitting contact between the jackets for a major portion of the length of the inner jacket as shown in the drawing and the difference in their relative hardnesses prevent elongation of the outer jacket from occurring in the forward portion and, instead, allow such elongation to occur only in that portion of the outer jacket to the rear of the area of contact between the jackets. Thus the nose of the outer jacket is prevented from creeping toward the inner jacket and the desired spacing is maintained between the nose portions of the jackets.

Another result of providing an inner jacket which is harder than the outer jacket is that, upon impact of the projectile, when the outer jacket is deformed, the inner jacket does not move. Thus the inner jacket acts as an anvil and the movement of the outer jacket toward the inner produces the crystal shear necessary to ignite the sensitive mixture between them.

In addition, the inner jacket contributes to safety in assembly of the projectile. The conical section between 2,975,710 Patented Mar. 21, 1961 the jackets must be closely controlled so as to insure ignition upon impact, yet cannot be so tight as to produce premature ignition when the inner jacket is inserted in the outer jacket and presses upon the sensitive mixture.

The jackets are constructed to include sufficient clearance to contain the preformed sensitive mixture without producing undue pressure. The tight-fitting contact and the difference in hardness between the jackets insures correct positioning of the compounds without producing undue pressure on the sensitive mixture.

This invention can best be understood by referring to the drawings in which:

Fig. 1 is a view, drawn to an enlarged scale and partly 'broken away and partly sectiOnedQdf the forward end of the projectile; and,

Fig. 2 is a view, drawn to an enlarged scale and partly broken away and partly sectioned, of a preferred embodiment of the forward end of the projectile.

Figs. 1 and 2 show the forward end of the projectile which comprises an outer jacket 5 which has a cylindrical body portion 6, an ogive shaped nose portion 7 and a nose tip 8. This outer jacket is made of any one of a number of known materials, such as gilding metal copper and 10% Zinc) so that it is easily deformed when the projectile strikes a target.

Coaxially disposed within the outer jacket is a solid body portion or penetrator 10, having a cylindrical portion 11 and a nose portion 12. Also within the outer jacket, coaxially disposed between the solid penetrator and the outer jacket, is an inner jacket 15 fabricated from a material substantially harder and less easily deformable than that used for the outer jacket (such as 1020 coldworked steel) and having at least four openings 16 through its wall near the tip 17. The inner jacket is thinwalled to enable it to be deformed and spread by the penetrator when the projectile strikes the target. The shape of the rear portion of the inner jacket is matched to that of the outer jacket so as to permit tight-fitting contact between the jackets over the distance I, which as shown in the drawing extends over a major portion of the length of the inner jacket.

In Fig. l the inner jacket 15 partitions the closed space between the outer jacket 5 and the solid penetrator 10 into two coaxial cuplike chambers 20 and 21, which chambers are in communication with each other through the openings 16 in the inner jacket. The shape of the forward portion of the inner jacket produces a space 20 of increasing cross-section toward the tip of the projectile, and insures uniform sensitivity over the angle a.

In Fig. 2, the forward portion of the inner jacket 15 is offset radially inward to produce a space 20 of uniform radial depth, thus insuring uniform sensitivity over the larger angle 13.

Chamber 20, preferably, contains an explosive 22 sensitive to impact, and chamber 21 contains incendiary material 23. When the projectile strikes a target, the nose 7 of the outer jacket is deformed toward the inner jacket 15, thereby causing explosive 22 to ignite. Fire from explosive 22 passes through the openings 16 and ignites incendiary material 23. Meanwhile both jackets 5 and 15 are opened by penetrator 10 which then acts against the target in the usual manner.

Thus by reason of this invention, proper dimensions and tolerances are maintained since elongation of the outer jacket takes place only in its rear portion leaving unaffected the critical spacing, and thus the sensitvity, of the forward portion of the projectile. The spacing selected depends upon such factors as safety in handling, range, projectile caliber and velocity, and the type of explosive and incendiary material carried by the projectile; the spacing being variable from about 0.016 inch in small caliber projectiles to about 0.125 inch in caliber 60 projectiles.

For example, in the 60 caliber projectile, the critical distance between the tips of the jackets is 0.125 inch, held to tolerance as small as $00015 inch, The total ength of the projectile is approximately 2.8 inches'and the length of tight-fitting contact between the jackets is approximately 0.8 inch, with a tolerance of 0.003 inch. Tests indicate that such a projectile is consistently effective against 0.020 inch laminar duraluminum at a range of 175 yards, whereas prior projectiles would function consistently only against 0.040 inch laminar duraluminurn at the same range. The length of the tight-fitting contact i between the inner and outer jackets depends on a number of factors including the initial degree of tension in the outer jacket, the types of metals selected for the jackets, the tightness of the fit of the outer jacket over the penetrator throughout the cylindrical portion of the projectile and the degree of clearance in the critical nose tips of the jackets.

By the term armor piercing is not meant the penetration of heavy plate but rather the piercing of the thinner plates used around gasoline tanks on aircraft. After the projectile of this invention has been slowed in velocity at long ranges, it is enabled to retain its sensitivity to ignite its primer and incendiary materials that causes it to be an advance in the art.

I claim:

1. In an armor-piercing projectile, the combination of a solid penetrator, an outer jacket cone-shaped in its forward portion, and an inner jacket substantially harder than the outer jacket, said inner jacket having a portion in tight-fitting contact with said outer jacket in the tapered portion of said outer jacket said portion in tight-fitting contact extending over a major portion of the inner jacket length to confine any elongation of the outer jacket to a rear portion and adjacent cylindrical portion when the outer jaccet is formed over the rear end of the projectile, whereby a criticalnose tip separation between these jackets is substantially unchanged, said inner jacket being axially spaced from said outer jacket to create a first cuplike chamber in the forward most portion of the projectile 'between the outer and inner jackets, the distance between the tips of the jackets varying from about 0.016 inch in a 22 caliber projectile to about 0.125 inch in a projectile of caliber, the spacing of said inner jacket also creating a second larger cuplike chamber between said inner jacket and said penetrator, said first chamber being loaded with an impact sensitive explosive and said second chamber being loaded with an incendiary mixture, said chambers communicating with each other through a plurality of holes in the forward portion of the wall of the inner jacket so ,that at impact a flame generated in the explosive can be transmitted to the incendiary mixture.

2. A projectile according to claim 1 in which the tightfitting contact between said jackets in a forward tapered portion is about 30% .of the total length of the projectile.

3. A projectile according to claim 2 in which the impact sensitive material is of substantially uniform radial depth longitudinally of the first chamber.

4. An incendiary projectile haying a body portion, a soft metal jacket contiguous said body portion and having a generally conical forward portion, an inner conical jacket of harder and less easily deformable material than the outer jacket, said inner jacket being in tight-fitting contactswith said outer jacket for a major portion of the length of the inner jacket and abutting said body portion to maintain a precise spacing between said jackets in a nose portion of said projectile, an incendiary material within said inner jacket, an impact sensitive explosive between said jackets in the projectile nose, the inner jacket being perforate adjacent the projectile nose for passage of flame from said impact sensitive explosive to ignite said incendiary material after deformation of a nose portion of the outer casing, whereby any elongation of the outer jacket on bending a rear portion is largely confined to a portion of the outer jacket-in rear of the inner jacket without danger of reducing the spacing between said jackets in a nose portion of said projectile.

5 A projectile according to claim 4 in which the outer jacket portion tightly fitting around said inner jacket is prestressed in tension.

6. A projectile according to claim 4 in which the space between said jackets occupied by said impact sensitive explosive is of substantially uniform radial depth.

References Cited in the file of this patent FOREIGN PATENTS 310,766 Germany June 17, 1920

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