US3756539A - Stabilization fins for projectiles - Google Patents

Stabilization fins for projectiles Download PDF

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Publication number
US3756539A
US3756539A US00157129A US3756539DA US3756539A US 3756539 A US3756539 A US 3756539A US 00157129 A US00157129 A US 00157129A US 3756539D A US3756539D A US 3756539DA US 3756539 A US3756539 A US 3756539A
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United States
Prior art keywords
fin
edge
elongated
depressions
fin assembly
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Expired - Lifetime
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US00157129A
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English (en)
Inventor
F Donner
T Kronholm
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Tampella Oy AB
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Tampella Oy AB
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Publication date
Application filed by Tampella Oy AB filed Critical Tampella Oy AB
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Publication of US3756539A publication Critical patent/US3756539A/en
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    • 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
    • F42B10/04—Stabilising arrangements using fixed fins
    • F42B10/06—Tail fins

Definitions

  • FIG. 1 A first figure.
  • This invention relates to an aerodynamic fin assembly for improved stabilization of objects in motion.
  • the invention is intended for use on projectiles such as launcher grenades and the like.
  • the stabilization fins for projectiles usually are fabricated by attaching a number of fins to a carrier tube. These fins are positioned so that they extend radially from the tube and are fabricated from lightweight sheet metal or molded plastic and provide only a minimal cross section which is not conducive to strength and rigidity. Thus, fins sometimes become damaged during handling or are caused to bend by the high pressure combustion gases generated during the projectile firing.
  • the fins of the present invention have been found to provide improved rigidity and strength and to be able to withstand normal abuse during handling. In addition, these fins are capable of withstanding without deformation the high pressure and high temperature combustion gases that are generated during the firing operation. Thus, it is an object of this invention to provide a more rigid and strengthened projectile fin which will withstand the damage and deformation normally associated with handling and firing of the projectile.
  • a further object of this invention is to provide a stabilization fin which will greatly improve the aerodynamic characteristics of the projectile.
  • the longitudinally extending ridges and hollows on the side surfaces of the fins of this invention in conjunction with the leading edge taper of the fin produce a minimum drag effect on the adjacent gas or air flow.
  • the projectiles motion is stabilized during its flight by the more streamlined gas flow directed along the fine assembly axis.
  • a further object of this invention is to provide a stabilization fin arrangement which reduces or eliminates vibrations thereby making the projectile aerodynamically stable and thus capable of following an accurate trajectory.
  • FIG. 1 shows an elevational view in partial section of a fin assembly for fin stabilized projectiles according to the present invention
  • FIG. 2 shows an end view in partial section of the fin assembly in FIG. 1 looking in the direction of arrow II
  • FIG. 3 shows a fin-stabilized projectile having the finassembly according to the present invention.
  • fin assembly 1 has a carrier tube 2 for mounting on the tail pipe of a fin-stabilized projectile and a number of fins 3 which extend radially from the outer surface of the carrier tube 2. Any number of fins can be attached, while in the present embodiment eight fins are shown.
  • Each fin 3 is provided on its side surface with a plurality of longitudinal depressions 4, 5 and 6 and ridges 7 and 8 between said depressions, each extending parallel to the carrier tubes longitudinal axis which corresponds to the longitudinal axis of the projectile as shown in FIG. 3.
  • the fin 3 has a leading edge portion 9, which extends outwardly and sharply rearward from a short forward projection 10.
  • the leading edge surface 9 extends for a distance equal to at least one-half to threequarters of the fin length. This distance is considered to be necessary in order to obtain the desired fin stabilization results.
  • the leading edge section 9 blends into a relatively short, straight edge 11 defining the greatest height of the fin and which extends parallel to the longitudinal axis of the carrier tube 2.
  • the trailing edge 12 of the fin extends rearwardly from the section 11 in a gentle inward slope to a blunt aft end 15.
  • the fin 3 projects beyond the length of the carrier tube 2 by a predetermined proportion.
  • fin 3 is provided with a connecting section 13 which extends obliquely from the aft blunt section 15 to the rear of the carrier tube 2.
  • the fin 3 of this invention has been disclosed to project beyond the front and rear edges of the carrier tube 2.
  • the fin projecting beyond the carrier tube 2 can be proportioned in any desired amount between the leading edge and the trailing edge but the total length of the projections should be limited to about 15 percent of the overall length of the fin attaching edge. This limitation is desirable to maintain proper strength in the joint between the fin and the carrier tube.
  • the position of the carrier tube with respect to the fin can be adjusted.
  • the position of the fin with respect to the projectile on which it is intended to be used can be determined.
  • depressions 4, 5 and 6 are of a shallow arcuate form.
  • the intermediate ridges 7 and 8 are formed by the intersection of the juxtaposed shallow arcs.
  • the outer depression 14 can be made slightly wider than the other depressions, if desired. Any number of depressions may be used depending upon the height of the individual fins. However, a range of three to six depressions has been found to provide satisfactory aerodynamic results. In this embodiment each side of fin 3 is shown with three depressions.
  • the width of each depression must be sufficient to prevent disturbance in the aerodynamic characteristics of the adjacent gas or air flow. It is desirable to make the depressions of relatively large width in relation to the fin height and to restrict the number of depressions used to a minimum.
  • Each depression is intentionally designed to begin and end at a predetermined distance from the leading edge 9 and the trailing edge 15, thus producing a shoulder area which results in improved strength of the fin.
  • the fin 3 is of a relatively narrow or thin cross section, while the leading edge 9 and the trailing edge form a knife-like cross section 3a and 3b.
  • the carrier tube and the fins may be formed as an integral unit or in separate sections.
  • the individual fins can then be attached to the carrier tube in any fashion that is desired; such as welding, T-slots, adhesives, etc. Any materials can be used but it would be advantageous to select material that would be both lightweight and yet provide sufficient strength. Materials in this category would be aluminum alloy, magnesium or various lightweight plastics or resins.
  • the leading edge taper of the fin 3 extends in an extremely sharp upward and rearward taper to the highest portion of fin 11.
  • the sharp taper in the fin profile results in considerably improved gas and air flow characteristics, contributing to prevention of vibrations or flutter in the fins.
  • air pulsations and turbulence are reduced, thus improving flight stability of the projectile.
  • the fin trailing edge profile can be modified to provide a continuous curve from the flat surface 11 to the rear of the carrier tube 2.
  • the depressions and ridges on the sides of the fins can be terminated at a distance from the trailing edge of the fin and thus create additional strength in this area.
  • the carrier tube 2 is sized to fit a mating portion on the projectile. Attachment to the projectile is accomplished very simply and easily by sliding the carrier tube of the fin assembly over the mating portion and securing or locking the tube 2 to the projectile by any means desired (not shown). Thus, if the projectile is not used the fin assembly can be removed and the projectile returned to storage by reversing the assembly procedure.
  • a fin assembly for stabilizing a projectile in motion comprising:
  • each opposing side having elongated, hollow arcuate depressions extending generally parallel to the longitudinal axis of the projectile
  • each depression being sufficient to prevent disturbance in the aerodynamic characteristics of the adjacent gas flow
  • the carrier member comprises a closed, hollow cylindrical tube that is shorter in length than the fin members and each fin member extends beyond the ends of the carrier tube member.
  • a fin assembly for stabilizing a body in motion comprising:
  • each opposing side having elongated, shallow arcuate recesses extending generally parallel to the longitudinal axis of the body
  • a fin assembly for stabilizing a body in motion comprising:
  • each opposing side having elongated, hollow depressions extending generally parallel to the longitudinal axis of the body
  • said depressions begin and end at a predetermined distance from the leading and trailing edges, respectively, thereby leaving a shoulder area of increased thickness at the leading and trailing edge to provide additional fin strength and rigidity.
  • a fin assembly for stabilizing a body in motion comprising:

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Toys (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Measurement Of Distances Traversed On The Ground (AREA)
US00157129A 1970-07-11 1971-06-28 Stabilization fins for projectiles Expired - Lifetime US3756539A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2034569A DE2034569C3 (de) 1970-07-11 1970-07-11 Leitwerk für flügelstabilisierte Geschosse

Publications (1)

Publication Number Publication Date
US3756539A true US3756539A (en) 1973-09-04

Family

ID=5776549

Family Applications (1)

Application Number Title Priority Date Filing Date
US00157129A Expired - Lifetime US3756539A (en) 1970-07-11 1971-06-28 Stabilization fins for projectiles

Country Status (10)

Country Link
US (1) US3756539A (enrdf_load_stackoverflow)
CA (1) CA948030A (enrdf_load_stackoverflow)
DE (1) DE2034569C3 (enrdf_load_stackoverflow)
DK (1) DK131586C (enrdf_load_stackoverflow)
FI (1) FI53500C (enrdf_load_stackoverflow)
FR (1) FR2099881A5 (enrdf_load_stackoverflow)
GB (1) GB1300361A (enrdf_load_stackoverflow)
IL (1) IL37028A (enrdf_load_stackoverflow)
NO (1) NO129818B (enrdf_load_stackoverflow)
SE (1) SE362951B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5158509A (en) * 1990-12-14 1992-10-27 The United States Of America As Represented By The United States Department Of Energy Composite stabilizer unit
WO2002021069A1 (en) * 2000-09-05 2002-03-14 Bofors Defence Ab Method and arrangement for extending the range of fire of a fin-stabilized artillery missile
WO2012031604A1 (de) * 2009-08-04 2012-03-15 Rheinmetall Waffe Munition Gmbh Mörsergranate
WO2022241127A1 (en) * 2021-05-12 2022-11-17 Crossbullet, Llc Projectile and firearm system
US12152865B2 (en) * 2021-05-12 2024-11-26 Crossbullet, Llc Projectile and firearm system
WO2025059734A1 (en) * 2023-09-19 2025-03-27 Transarmory Ltd Universal stabilizer for ammunition

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES8706942A1 (es) * 1986-04-16 1987-07-01 Esperanza & Cie Sa Granada para mortero
DE3927918A1 (de) * 1989-08-24 1991-02-28 Rheinmetall Gmbh Fluegelstabilisiertes geschoss

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1879840A (en) * 1930-05-22 1932-09-27 Brandt Edgar William Bladed projectile
GB431551A (en) * 1933-12-01 1935-07-10 Jean Fabry Improvements in stabilising and damping devices
FR802042A (fr) * 1935-05-12 1936-08-25 Stabilisateur à correction automatique
US2597703A (en) * 1946-02-07 1952-05-20 Us Navy Rocket fin

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1879840A (en) * 1930-05-22 1932-09-27 Brandt Edgar William Bladed projectile
GB431551A (en) * 1933-12-01 1935-07-10 Jean Fabry Improvements in stabilising and damping devices
FR802042A (fr) * 1935-05-12 1936-08-25 Stabilisateur à correction automatique
US2597703A (en) * 1946-02-07 1952-05-20 Us Navy Rocket fin

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5158509A (en) * 1990-12-14 1992-10-27 The United States Of America As Represented By The United States Department Of Energy Composite stabilizer unit
WO2002021069A1 (en) * 2000-09-05 2002-03-14 Bofors Defence Ab Method and arrangement for extending the range of fire of a fin-stabilized artillery missile
US20040094660A1 (en) * 2000-09-05 2004-05-20 Torsten Wik Method and arrangement for extending the range of fire of a fin-stabilized artillery missile
US6926228B2 (en) 2000-09-05 2005-08-09 Bofors Defence Ab Method and arrangement for extending the range of fire of a fin-stabilized artillery missile
WO2012031604A1 (de) * 2009-08-04 2012-03-15 Rheinmetall Waffe Munition Gmbh Mörsergranate
US20220373308A1 (en) * 2021-05-12 2022-11-24 Crossbullet, Llc Projectile and firearm system
WO2022241127A1 (en) * 2021-05-12 2022-11-17 Crossbullet, Llc Projectile and firearm system
EP4379310A2 (en) 2021-05-12 2024-06-05 Crossbullet, LLC Projectile and firearm system
EP4379310A3 (en) * 2021-05-12 2024-07-10 Crossbullet, LLC Projectile and firearm system
US12111140B2 (en) * 2021-05-12 2024-10-08 Crossbullet, Llc Projectile and firearm system
US12152865B2 (en) * 2021-05-12 2024-11-26 Crossbullet, Llc Projectile and firearm system
US20250123087A1 (en) * 2021-05-12 2025-04-17 Crossbullet, Llc Projectile and firearm system
WO2025059734A1 (en) * 2023-09-19 2025-03-27 Transarmory Ltd Universal stabilizer for ammunition

Also Published As

Publication number Publication date
DK131586C (da) 1976-01-05
CA948030A (en) 1974-05-28
FR2099881A5 (enrdf_load_stackoverflow) 1972-03-17
FI53500C (fi) 1978-05-10
SE362951B (enrdf_load_stackoverflow) 1973-12-27
DE2034569A1 (de) 1972-01-13
NO129818B (enrdf_load_stackoverflow) 1974-05-27
DE2034569C3 (de) 1975-04-10
DE2034569B2 (de) 1974-08-15
FI53500B (enrdf_load_stackoverflow) 1978-01-31
IL37028A (en) 1974-10-22
DK131586B (da) 1975-08-04
IL37028A0 (en) 1971-11-29
GB1300361A (en) 1972-12-20

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