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WO1996041113A1 - Projectiles a densite et repartition de masse modulables - Google Patents

Projectiles a densite et repartition de masse modulables Download PDF

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Publication number
WO1996041113A1
WO1996041113A1 PCT/US1996/008886 US9608886W WO9641113A1 WO 1996041113 A1 WO1996041113 A1 WO 1996041113A1 US 9608886 W US9608886 W US 9608886W WO 9641113 A1 WO9641113 A1 WO 9641113A1
Authority
WO
WIPO (PCT)
Prior art keywords
projectile
mass
center
mass density
powdered material
Prior art date
Application number
PCT/US1996/008886
Other languages
English (en)
Inventor
Richard A. Lowden
Thomas M. Mccoig
Joseph B. Dooley
Cyrus M. Smith
Original Assignee
Lockheed Martin Energy Systems, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lockheed Martin Energy Systems, Inc. filed Critical Lockheed Martin Energy Systems, Inc.
Priority to EP96917176A priority Critical patent/EP0779967A4/fr
Priority to AU59844/96A priority patent/AU5984496A/en
Publication of WO1996041113A1 publication Critical patent/WO1996041113A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B10/00—Means for influencing, e.g. improving, the aerodynamic properties of projectiles or missiles; Arrangements on projectiles or missiles for stabilising, steering, range-reducing, range-increasing or fall-retarding
    • F42B10/02—Stabilising arrangements

Definitions

  • the present invention relates generally to projectile design and fabrication techniques, and more specifically, to projectiles having controllable dynamic properties which improve flight characteristics.
  • a projectile pursuant to the present invention is designed to place the center of pressure relative to the center of gravity in a manner that achieves a desired aerodynamic effect and to choose the mass distribution so as to change the dynamic behavior of the projectile.
  • Firearms and the projectiles which they deliver define a weapon system. Since the advent of the rifled barrel and the cylindro- conical bullet, relatively little has been done 10 to optimize the performance of the system.
  • Performance can be any one of several measures including accuracy, dispersion, variability of impact point, energy retained, velocity retained and, terminal effects, among others.
  • Projectiles of existing technology use more or less homogeneous materials for construction. The most frequently used are lead for cores and copper or "gilding metal as jackets.”
  • shaping of the projectile and the use of 20 cavities or hollows inside have been used to change projectile dynamics somewhat, the use of homogeneous materials of a density no greater than lead has limited the amount of control over stability which can be exercised by the 25 designer.
  • the weapon must have its rifling twist (rotation per unit length along the barrel) fixed at manufacture. The twist will have been chosen to provide a reasonable accuracy for the most commonly used bullet at the most commonly expected velocity.
  • the twist fixes the ratio of spin speed (and attendant gyroscopic stabilization) to forward velocity for a given weapon. This ratio may not be optimal for some (or even for any) projectile weights, shapes, and velocities.
  • the designer now needing the longer bullet for weight purposes, faces an even more adverse stability situation. Moreover, the heavier bullet will be likely to travel at lower velocity.
  • the fixed twist rifling means that the stabilizing effect of the spin will be greatly decreased for this inherently less stable bullet.
  • An object of the present invention is to provide a method of forming projectiles from different powdered constituent materials, wherein the mass distribution of the materials is selected to achieve a desired aerodynamic effect.
  • Another object of the present invention is to provide a projectile having increased stability, and thus range, which results from delaying the growth of projectile yaw angles (angular deviation of the projectile centerline from the line of flight) , where such effect is desirable.
  • Another object of the present invention is to provide an inherently stable projectile which can be fired at higher velocities, which require higher temperatures and pressures within the barrel, without necessarily using a rifled barrel.
  • Another object of the present invention is to provide shot or shot-like projectiles for a shotshell capable of maintaining a tighter pattern at all ranges. 10
  • a projectile having a body having a tapered or rounded forward portion and a cylindrical rearward portion, and having a center of gravity and a center of pressure, the 15 body being made of at least two constituent materials of different weight, and being selected and distributed within the body to position the center of gravity relative to the center of pressure in a manner that achieves a 20 desired aerodynamic effect.
  • Fig. 1 is a schematic view of a projectile moving in a direction of flight, and having a center of gravity behind the center of pressure
  • Fig. 2 is a schematic view of a projectile moving in a direction of flight, and having a center of gravity forward of the center of pressure
  • Figure 3 is a schematic, vertical cross sectional view of a projectile according to another embodiment of the present invention.
  • Figure 4 is a schematic, side elevational view of a projectile according to another embodiment of the present invention.
  • the present invention entails the selection, distribution and/or consolidation of materials to form a projectile with the center of gravity placed relative to the center of pressure to achieve a desired aerodynamic effect. This is accomplished by forming a projectile body having at least two portions, one having a greater mass density than the other. The difference in mass densities is selected to place the center of gravity of the projectile body at a position relative to the body's center of pressure which achieves a desired aerodynamic effect.
  • Mass density, p is the mass of a material divided by the volume of the material.
  • a greater mass density can be achieved in one body portion by using materials having greater mass (such as lead versus aluminum) .
  • a single powdered material could be used for both body portions, with each portion subjected to different consolidation or "densification” forces, so that one achieves a higher theoretical density, and thus higher mass density, than the other.
  • a combination of different constituent materials and different consolidation forces could also be employed to achieve the desired location of the center of gravity.
  • a projectile 20 having enhanced, inherent aerodynamic stability has a forward portion 22 and a rearward portion 24.
  • the forward portion 22 is approximately conically or ogive shaped and the rearward portion 24 is substantially cylindrically shaped. Other shapes of projectiles may be employed.
  • the forward portion 22 has a greater mass density than the rearward portion 24.
  • the greater mass density can be achieved by forming the forward portion 22 from a first material having greater mass density than a second material which is used to form the rearward portion 24.
  • both portions could also be made from the same powdered material, but consolidated to achieve different theoretical densities. For example, tungsten carbide powder of sufficient quantity to form the forward portion 22 is placed in a mold and subjected to pressure sufficient to achieve 95% theoretical density.
  • a second quantity of powder, sufficient to form the rearward portion 24, is placed in the mold after pressing the 5 forward portion 22, and then subjected to pressure sufficient to achieve 70% theoretical density.
  • the forward portion 22 would thus have a greater mass density than the rearward portion 24 (since more matter has been placed in a given 10 volume) .
  • the forward portion 22 By designing the forward portion 22 to have a greater mass density than the rearward portion 24, the center of gravity 26 is shifted forward of the center of pressure 28. This results in 15 the creation of a restoring moment, indicated by the curved directional arrow in Figure 2, due to the inertial force vector 28 not overlapping the drag force vector 30.
  • the projectile can be made more stable by shifting the center of gravity to a more forward position.
  • the reverse configuration could be used to de- stabilize the projectile.
  • the present invention envisions controlled movement of center of pressure and center of gravity to achieve any desired performance characteristic.
  • the present invention also includes moving the center of
  • a projectile 32 according to another embodiment of the present invention is designed to have increased
  • a projectile 32 having an increased polar mass moment of inertia 5 includes a rearwardly disposed annular portion 34, having a greater mass density than a relatively lower mass density main portion 36.
  • the high mass density annular portion 34 will increase the gyro stabilization of the 10 projectile, while reducing the mass density of the main portion 36 preserves the same total weight of a conventional projectile of the same dimensions.
  • the bullet design process in any of the aforementioned embodiments, entails the use of unconventional materials, the selection and distribution of which leads to a desirable 25 positioning of the center of gravity and the mass moments of inertia.
  • a typical design process involves (l) selecting optimization criteria, caliber, and weapon, (2) selecting projectile shape and/or weight, (3) computing center of gravity location, and axial and polar mass moments of inertia, (4) determining special features requiring mass concentration or reduction, (5) incorporating mass alterations and re-computing properties,
  • test firing projectiles and (8) making further adjustments to achieve desired performance.
  • a projectile 38 for use in shotgun rounds has a first portion 40 disposed at the forward end of the projectile 38 and a second portion 42.
  • the second portion 42 is substantially cylindrically shaped, while the first portion is conically or spherically shaped at its distal end.
  • the first portion 40 has a greater mass density than the second portion. The greater mass density allows the center of gravity to be shifted forward, thus providing increased or even inherent stability for the projectile.
  • Each portion 40 and 42 can be formed using powder metallurgy techniques. Different powdered materials can be selected to achieve the desired distribution of mass and location of 5 the center of gravity. Consolidation of the powdered materials can be by any one of several known techniques.
  • a 12 gage shotgun (with a nominal bore diameter of 0.729 inches) 20 will accommodate seven projectiles 38 of 0.243 inch diameter and 0.75 inches long in a hexagonal close pack array 44 .
  • Each projectile weighs about 52 grains which yields a total "shot charge" of 364 grains, or only a few 25 percent less than standard pellet 00 buckshot.
  • Other combinations and geometries are possible.
  • they can be made to be frangible, so as to shatter on initial impact, thus preventing a ricochet of an intact massive 5 projectile.
  • Plastics could be used for the low density materials in any of the embodiments.
  • the powdered ingredients can be any of 5 those mentioned in U.S. application serial no. 08/267,895, filed July 6, 1994, which is incorporated herein by reference. However, other materials may be employed, including plastics and lead. 10
  • Each constituent material may be a metal, metal compound, metal alloy, or a mixture of metals, metal compounds and/or metal alloys.
  • An example of a suitable compound is tungsten carbide, while suitable elements include 15 tungsten and tantalum. Each is selected according to its elemental density (as opposed to the density of a body formed by consolidating a powder) .
  • Both the lighter and heavier materials may include a binder and a wetting 20 agent to enhance the wettability of the element and its binder.
  • binder constituent may be elemental, 25 compounded or alloyed as noted with respect to the powder, and may also comprise a mixture of elements, compounds and/or alloys, depending on the physical properties of each and the desired physical properties of the finished product.
  • a consolidation technique is selected to achieve a desired fracture toughness, or other physical property. For example, an annealing step provided after cold
  • frangibility is also a function of the degree of densification (expressed as a percentage of theoretical
  • Additives can also be used to
  • Materials for use as the heavier constituent include tungsten, tungsten carbide, tantalum, lead, and any other metals, metal alloys or other materials with similar
  • Density and frangibility can be customized for individual needs, by considering the density and mechanical properties of the individual constituents.
  • Tables II and III serve as guidelines for material selection:
  • the hardness of lead is 3 HB in similar units.
  • the projectiles described herein could replace any bullet in current use. This would benefit any organization and individual that uses ammunition for training, self defense, police applications, military, hunting, sport shooting, etc.
  • the term "projectile” refers to any munitions round, or the core to the projectile of a munitions round.
  • the projectiles of the present invention could be the core of a jacketed round.
  • the amount, mixture and type of materials are selected according to the desired ballistic properties of the projectile as per the present invention.
  • the forming techniques can be such that the core is preformed or formed in the jacket as by swaging. In either event, the amount of consolidation is controlled to achieve desired frangibility and distribution of mass density characteristics.
  • the projectiles encompassed in the present invention could include, in addition to bullets, virtually any type of artillery round, such as those capable of exploding on impact (and thus incorporating an explosive charge) , a hand grenade, a rocket warhead, etc.
  • any number of different body portions, and locations, can be employed to achieve the desired effect.
  • the different portions can be interconnected, interfitted, integrally formed, fixedly 5 connected through any available means, or loosely connected, depending on the desired outcome.
  • integrally forming a quantity of powder can be placed in a mold and pressed. Then a quantity of either the same or 10 a different powder can be added to the press without removing the consolidated first quantity, and then subjected to the same or a different consolidation force.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Powder Metallurgy (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Ceramic Capacitors (AREA)

Abstract

Projectile (36) présentant des caractéristiques aérodynamiques inhérentes grâce à une masse volumique différentielle situant le centre de gravité dans une position voulue par rapport au centre de pression.
PCT/US1996/008886 1995-06-07 1996-06-05 Projectiles a densite et repartition de masse modulables WO1996041113A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP96917176A EP0779967A4 (fr) 1995-06-07 1996-06-05 Projectiles a densite et repartition de masse modulables
AU59844/96A AU5984496A (en) 1995-06-07 1996-06-05 Projectiles having controllable density and mass distributio n

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47441295A 1995-06-07 1995-06-07
US08/474,412 1995-06-07

Publications (1)

Publication Number Publication Date
WO1996041113A1 true WO1996041113A1 (fr) 1996-12-19

Family

ID=23883418

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/008886 WO1996041113A1 (fr) 1995-06-07 1996-06-05 Projectiles a densite et repartition de masse modulables

Country Status (4)

Country Link
EP (1) EP0779967A4 (fr)
AU (1) AU5984496A (fr)
CA (1) CA2199267A1 (fr)
WO (1) WO1996041113A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004027341A1 (fr) * 2002-09-20 2004-04-01 Lockheed Martin Corporation Penetrateur et son procede d'utilisation
US6843179B2 (en) 2002-09-20 2005-01-18 Lockheed Martin Corporation Penetrator and method for using same
US7017495B2 (en) * 2003-05-06 2006-03-28 Richard Sexton Gun firing method for dispersion of projectiles in a pattern
EP1999429A4 (fr) * 2006-02-15 2012-11-07 Defense Technology Corp Of America Munition non létale
EP3333450A1 (fr) * 2016-12-08 2018-06-13 MBDA France Ensemble d'équilibrage à bagues d'équilibrage pour missile et missile pourvu d'un tel ensemble d'équilibrage

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025186549A1 (fr) * 2024-03-04 2025-09-12 Globalforce Ip Limited Fléchette et lanceur

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US421932A (en) * 1890-02-25 Territory
GB538268A (en) * 1939-11-10 1941-07-28 Martin Littmann Improvements in projectiles for military weapons
US2398648A (en) * 1944-03-01 1946-04-16 Gen Electric Protection of electric systems
US2409307A (en) * 1942-07-01 1946-10-15 Gen Motors Corp Projectile
US3880083A (en) * 1967-05-19 1975-04-29 Us Army Bimetallic mass stabilized flechette
US4016817A (en) * 1975-10-10 1977-04-12 Moises Arciniega Blanco Bullet for hunting shotguns
US4301733A (en) * 1978-04-22 1981-11-24 Moises Arciniega Blanco Bullet for smooth bore shotguns
US4517898A (en) * 1979-12-14 1985-05-21 Davis Dale M Highly accurate projectile for use with small arms
US4603637A (en) * 1984-10-31 1986-08-05 The United States Of America As Represented By The Secretary Of The Air Force Variable density frangible projectile
US5012743A (en) * 1988-12-05 1991-05-07 Fabrique National Herstal, En Abrege Fn, Societe Anonyme High-performance projectile
US5069138A (en) * 1989-01-02 1991-12-03 Lars Ekbom Armor-piercing projectile with spiculating core
US5070791A (en) * 1990-11-30 1991-12-10 The United States Of America As Represented By The Secretary Of The Army Projectile tail cone
US5279787A (en) * 1992-04-29 1994-01-18 Oltrogge Victor C High density projectile and method of making same from a mixture of low density and high density metal powders
WO1994011697A1 (fr) * 1992-11-09 1994-05-26 Leif Persson Materiau pour munitions de chasse et procede de production dudit materiau
US5399187A (en) * 1993-09-23 1995-03-21 Olin Corporation Lead-free bullett

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR468193A (fr) * 1913-11-03 1914-06-30 Alexandre Dobregeansky Projectile pour armes à feu
FR1231010A (fr) * 1950-12-29 1960-09-26 Cie Ind Des Metaux Electroniqu Projectiles à corps ou noyau composite et leur procédé de fabrication
CH347454A (de) * 1956-03-21 1960-06-30 Dipag Ltd Geschoss
DE3335997A1 (de) * 1983-10-04 1985-04-11 Rheinmetall GmbH, 4000 Düsseldorf Uebungsgeschoss
DE3635738A1 (de) * 1986-10-21 1988-05-19 Rheinmetall Gmbh Treibkaefig-fluggeschoss-anordnung

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US421932A (en) * 1890-02-25 Territory
GB538268A (en) * 1939-11-10 1941-07-28 Martin Littmann Improvements in projectiles for military weapons
US2409307A (en) * 1942-07-01 1946-10-15 Gen Motors Corp Projectile
US2398648A (en) * 1944-03-01 1946-04-16 Gen Electric Protection of electric systems
US3880083A (en) * 1967-05-19 1975-04-29 Us Army Bimetallic mass stabilized flechette
US4016817A (en) * 1975-10-10 1977-04-12 Moises Arciniega Blanco Bullet for hunting shotguns
US4301733A (en) * 1978-04-22 1981-11-24 Moises Arciniega Blanco Bullet for smooth bore shotguns
US4517898A (en) * 1979-12-14 1985-05-21 Davis Dale M Highly accurate projectile for use with small arms
US4603637A (en) * 1984-10-31 1986-08-05 The United States Of America As Represented By The Secretary Of The Air Force Variable density frangible projectile
US5012743A (en) * 1988-12-05 1991-05-07 Fabrique National Herstal, En Abrege Fn, Societe Anonyme High-performance projectile
US5069138A (en) * 1989-01-02 1991-12-03 Lars Ekbom Armor-piercing projectile with spiculating core
US5070791A (en) * 1990-11-30 1991-12-10 The United States Of America As Represented By The Secretary Of The Army Projectile tail cone
US5279787A (en) * 1992-04-29 1994-01-18 Oltrogge Victor C High density projectile and method of making same from a mixture of low density and high density metal powders
WO1994011697A1 (fr) * 1992-11-09 1994-05-26 Leif Persson Materiau pour munitions de chasse et procede de production dudit materiau
US5399187A (en) * 1993-09-23 1995-03-21 Olin Corporation Lead-free bullett

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0779967A4 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004027341A1 (fr) * 2002-09-20 2004-04-01 Lockheed Martin Corporation Penetrateur et son procede d'utilisation
US6843179B2 (en) 2002-09-20 2005-01-18 Lockheed Martin Corporation Penetrator and method for using same
US7017495B2 (en) * 2003-05-06 2006-03-28 Richard Sexton Gun firing method for dispersion of projectiles in a pattern
EP1999429A4 (fr) * 2006-02-15 2012-11-07 Defense Technology Corp Of America Munition non létale
EP3333450A1 (fr) * 2016-12-08 2018-06-13 MBDA France Ensemble d'équilibrage à bagues d'équilibrage pour missile et missile pourvu d'un tel ensemble d'équilibrage
WO2018104594A1 (fr) * 2016-12-08 2018-06-14 Mbda Ensemble d'équilibrage à bagues d'équilibrage pour missile et missile pourvu d'un tel ensemble d'équilibrage
FR3060089A1 (fr) * 2016-12-08 2018-06-15 Mbda France Ensemble d'equilibrage a bagues d'equilibrage pour missile et missile pourvu d'un tel ensemble d'equilibrage
US11293728B2 (en) 2016-12-08 2022-04-05 Mbda France Balancing assembly comprising balancing rings for a missile and missile provided with such a balancing assembly

Also Published As

Publication number Publication date
EP0779967A4 (fr) 1998-01-07
EP0779967A1 (fr) 1997-06-25
CA2199267A1 (fr) 1996-12-19
AU5984496A (en) 1996-12-30

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