Fin-stabilized ammunition
AssigneeGeneral Dynamics Ordnance and Tactical Systems, Inc.
InventorsGuy H. Henry, Donald E. Dillard, Rao Yalamanchili, Dennis J. Conway, Rick D. Wright, Gary C. Fleming, Alan N. Cohen, Roger E. Joinson, Gene Venable, Thomas Doris, Albert S. Tatka, Jr.
Life of this patent
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Abstract
Tracer visibility of APFSDS projectiles can be enhanced through a combination of increased steady state spin rate, reduced muzzle obscuration, and optimized airflow over the stabilizing fin geometry of the sub-projectile. The preferred means to increase steady state spin rates of the sub-projectile is to incline or deflect the fin blade tip portion, creating a larger, hotter burning, tracer plume.
Claims14
An ammunition cartridge centered about a longitudinal axis, the ammunition cartridge comprising:
- a case having a base and a sidewall extending from the base to a mouth of the case and bounding an interior, the case dimensioned to maintain the armor piercing projectile substantially centered along the longitudinal axis;
- an armor piercing projectile having a fore portion proximate to the mouth of the case and an aft portion proximate to the base of the case, the armor piercing projectile comprising:
- a body having a nose proximate the fore portion of the armor piercing projectile, a tail proximate the aft portion of the armor piercing projectile and a cylindrical pocket within the tail of the body;
- a tracer positioned within the cylindrical pocket of the body;
- and
- a plurality of stabilizing fin blades projecting from the body;
- a sabot securing the projectile body to the case proximate the mouth of the case;
- a propellant charge located in the case interior,
- wherein the plurality of stabilizing fin blades each have a first portion extending substantially longitudinally;
- a second portion, outboard of the first portion and having:
- a first subportion extending substantially longitudinally;
- and a second subportion, aft of the first subportion having a first surface portion inclined relative to a longitudinal direction by an angle of between about 3.5 and about 6.0 degrees;
- and
- whereby when the armor piercing projectile has an increased steady state spin rate the tracer visibility improves.
An armor piercing fin-stabilize discarding sabot projectile comprising a body having a tracer positioned at an aft end thereof and wherein at least two fin blades mounted on said body are formed having:
- a first portion extending substantially longitudinally;
- a second portion, outboard of the first portion and having:
- a first subportion extending substantially longitudinally;
- and
- a second subportion, aft of the first subportion, and inclined relative to the first subportion by an angle of between about 3.5 and about 6.0 degrees;
- and
- whereby when the armor piercing projectile has an increased steady state spin rate the tracer visibility improves.
An armor piercing fin-stabilized discarding sabot projectile with a tracer, the armor piercing fin-stabilized discarding sabot projectile comprising;
- a fore portion distal to the tracer and an aft portion proximate to the tracer, the tracer being substantially centered along a longitudinal axis;
- at least two tail fin blades each having:
- a first portion extending substantially longitudinally along said axis;
- a second portion, outboard of the first portion having:
- a first subportion extending substantially longitudinally along said axis;
- and a second subportion, aft of the first subportion having a portion extending by an angle θ between about 3.5 and about 6.0 degrees relative to the longitudinal axis, effective to impart the projectile with a steady-state spin rate (SSSR) within lower and upper limits respectively defined by the equations:
- (SSSR-340)/(C-25)=(99-SSSR)/(120-C);
- and
- (SSSR-420)/(C-25)=(122-SSSR)/(120-C);
- where SSSR is in rps and C is a caliber in mm;
- and
- whereby when the armor piercing fin-stabilized discarding sabot projectile is fired at a muzzle velocity of between 1300 and 1500 m/s;
- and
- whereby when the armor piercing fin-stabilized discarding sabot projectile has an increased steady state spin rate the tracer visibility improves.
An armor piercing fin-stabilized discarding sabot projectile with a tracer for firing from a barreled weapon of nominal 25 mm caliber wherein:
- the armor piercing fin-stabilized discarding sabot projectile comprises a fore portion distal to the tracer and an aft portion proximate to the tracer, the tracer substantially centered along the longitudinal axis;
- and
- fin blades each having:
- a first portion extending substantially longitudinally;
- a second portion, outboard of the first portion and having:
- a first subportion extending substantially longitudinally;
- and a second subportion, aft of the first subportion, and having a first surface portion inclined relative to a longitudinal direction by an angle θ of between 3.5 and 6.0 degrees are fixed to the projectile adjacent to the aft portion proximate to the tracer substantially in alignment with the longitudinal axis;
- and
- whereby when the armor piercing fin-stabilized discarding sabot projectile is fired from the barreled weapon with a muzzle velocity the angle θ of between 3.5 and 6.0 degrees is effective to achieves a steady-state spin rate (SSSR) of at least 340 rps;
- and
- whereby the tracer visibility is improved with the increased SSSR.
Dependencies are inferred from the claim text.