US3890902A - Projectile - Google Patents

Abstract

A projectile having a pair of longitudinally spaced rotating bands, one of which is forwardly adjacent the projectile center of gravity to provide a projectile bearing surface that minimizes projectile yaw within and at the exit of the gun barrel. An improved aerodynamic stability of the projectile at the gun muzzle exit is obtained, as well as increased projectile accuracy at the target.

Description

United States Patent Travor et a1.

[ June 24, 1975 PROJECTILE Inventors: Bruce W. Travor, Holland, Pa;

Samuel L. Brown, Willingboro, NJ.

The United States of America as represented by the Secretary of the Army, Washington. DC

Filed: Dec. 4, 1973 Appl. No: 421,570

Assignee:

U.S. Cl. 102/93; 102/52; 102/92.4 Int. Cl. F42B 13/16; F4213 13/06 Field of Search 102/93, 92.1, 92.2, 92.4,

References Cited UNITED STATES PATENTS 12/1937 Foulke 102/92.l

2,110,264 3/1938 Gerlich l02/92.l 3,446,147 5/1969 Engel et a1 102/93 3,447,466 6/1969 Engcl 102/93 Primary Examiner-Robert F. Stahl Attorney, Agent, or FirmRobert P. Gibson; Nathan Edelberg; William Sommer [57] ABSTRACT A projectile having a pair of longitudinally spaced rotating bands, one of which is forwardly adjacent the projectile center of gravity to provide a projectile bearing surface that minimizes projectile yaw within and at the exit of the gun barrel. An improved aerodynamic stability of the projectile at the gun muzzle exit is obtained, as well as increased projectile accuracy at the target.

3 Claims, 1 Drawing Figure 1 PROJECTILE The invention described herein may be manufactured. used. and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to projectiles, and more particularly to an ammunition projectile having a nondiscarding sabot body and an aerodynamic windshield or nose.

Prior ammunition projectiles normally have barrel contacting surfaces at their rearwardly located rotating band and the forwardly located origin of ogive for the windshield or nose portion. This type of arrangement enables the projectile to travel through the rifled gun barrel at a cocked position, thereby inducing a certain amount of projectile at muzzle exit yaw that adversely affects the aerodynamic stability of the projectile as well as its firing accuracy.

One of the objects of the invention is to provide an ammunition projectile in which the yaw at muzzle exit is minimized.

Another object of the invention is to provide such a projectile having an improved aerodynamic stability.

A further object of the invention is to provide such a projectile having increased firing accuracy.

These and other objects, features and advantages will become more apparent from the following description and accompanying drawing which is an elevational view, partially broken away in section, of a preferred ammunition projectile embodying the principles of the invention.

The ammunition projectile, shown generally at 10, has a sabot body portion 11 having a forwardly opening cavity 12 that terminates in an enlarged internally threaded forward end 13 by which an appropriately threaded rearward portion 14 of a windshield or nose member 15 is secured with a heavy penetrator 16 of suitably contoured metallic material seated or positioned in the cavity 12. The rearward end of the sabot body has a crimping groove 17 for attachment of a cartridge case, and slightly forward thereof, a first rotating band 18 of a copper base material for conventional engraving by and sealing of the rifling grooves of an associated gun barrel (not shown).

Spaced longitudinally from and forward of the rotating band 18 is a second or mid rotating band 19 of similar material but of a slightly reduced diameter. Preferably, the ratio of the external or maximum surface diameters of the second and first rotating bands is 0.975. although a satisfactory ratio range of 0.965 to 0.985 will preclude excessive operational chamber pressures. Preferably, the projectile center of gravity is located rearwardly adjacent the mid-point of the second or forward rotating band to attain minimum projectile eccentricity in the gun barrel and maximum aerodynamic stability.

The second or mid rotating band assists in imparting projectile spin and also functions as a forward alignment guide for the projectile as it travels through and exits from the gun barrel. It has been found that by positioning the second rotating band only a proportional distance from the forwardmost peripheral edge of the first rotating band as compared to the distance between the latter and the origin of ogive (located at 20 and no longer functioning as the forward guide). a substantial reduction of the yaw muzzle exit angle is obtained for the launched projectile. For example, the proportional distance of 42.6% for the preferred projectile will'reduce the yaw muzzle exit angle by in excess of 50%.

Various modifications, alterations or changes may be resorted to without departing from the scope of the invention as defined in the appended claims.

We claim:

1. In an aerodynamically stable projectile having a heavy penetrator positioned within a non-discarding sabot,

said non-discarding sabot including a sabot body portion and an aerodynamic windshield nose member threadedly secured thereto,

said heavy penetrator secured within said sabot body portion and said nose member,

said nose member having a forward tapered external surface. said nose tapered surface terminating in a closed forward end,

said sabot body portion having a forward exterior surface containing a cylindrical portion and a tapered portion forwardly thereof defining an origin of ogive therebetween, said tapered sabot portion being a mating continuation of said nose tapered surface,

said sabot body portion carrying a first rotating band rearward of the center of gravity of said projectile, and

a second rotating band having a mid-point located on said sabot body portion forward of said projectile center of gravity.

2. The structure in accordance with claim 1 wherein the ratio of maximum surface diameters of said second and first rotating bands is in the range of 0.965 to 0.985.

3. The structure of claim 2 wherein said ratio is 0.975.

Claims (3)

1. In an aerodynamically stable projectile having a heavy penetrator positioned within a non-discarding sabot, said non-discarding sabot including a sabot body portion and an aerodynamic windshield nose member threadedly secured thereto, said heavy penetrator secured within said sabot body portion and said nose member, said nose member having a forward tapered external surface, said nose tapered surface terminating in a closed forward end, said sabot body portion having a forward exterior surface containing a cylindrical portion and a tapered portion forwardly thereof defining an origin of ogive therebetween, said tapered sabot portion being a mating continuation of said nose tapered surface, said sabot body portion carrying a first rotating band rearward of the center of gravity of said projectile, and a second rotating band having a mid-point located on said sabot body portion forward of said projectile center of gravity.

2. The structure in accordance with claim 1 wherein the ratio of maximum surface diameters of said second and first rotating bands is in the range of 0.965 to 0.985.

3. The structure of claim 2 wherein said ratio is 0.975.

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