EP0076990B1 - Ailettes stabilisatrices pour projectile - Google Patents

Ailettes stabilisatrices pour projectile Download PDF

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Publication number
EP0076990B1
EP0076990B1 EP82109120A EP82109120A EP0076990B1 EP 0076990 B1 EP0076990 B1 EP 0076990B1 EP 82109120 A EP82109120 A EP 82109120A EP 82109120 A EP82109120 A EP 82109120A EP 0076990 B1 EP0076990 B1 EP 0076990B1
Authority
EP
European Patent Office
Prior art keywords
fins
projectile
propellant charge
barrel
assembly
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
EP82109120A
Other languages
German (de)
English (en)
Other versions
EP0076990A3 (en
EP0076990A2 (fr
Inventor
Jan-Erik Sandberg
Torbjörn Pramskog
Bengt Larsson
Börje Johansson
Sven Andersson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AFFAERSVERKET FFV
Original Assignee
Affarsverket FFV
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 Affarsverket FFV filed Critical Affarsverket FFV
Publication of EP0076990A2 publication Critical patent/EP0076990A2/fr
Publication of EP0076990A3 publication Critical patent/EP0076990A3/en
Application granted granted Critical
Publication of EP0076990B1 publication Critical patent/EP0076990B1/fr
Expired legal-status Critical Current

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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
    • F42B10/14—Stabilising arrangements using fins spread or deployed after launch, e.g. after leaving the barrel
    • F42B10/20—Stabilising arrangements using fins spread or deployed after launch, e.g. after leaving the barrel deployed by combustion gas pressure, or by pneumatic or hydraulic forces

Definitions

  • the present invention relates to a stabilizing fin assembly for a rotating or non-rotating projectile designed to be discharged from a rifled or smooth barrel by means of propellant charge gases, having a plurality of elongated fins, rotatably mounted at one end, which are arranged so that during the passage of the projectile through the barrel they are in the retracted position, in which the fins are placed on edge extending mutually in parallel and mainly in the lengthwise direction of the projectiles.
  • the fins are normally extended by means of spring force or with the aid of lifting surfaces arranged on the fins which are affected by the wind velocity.
  • the method is also known of utilising the gas pressure produced by the propellant charge for extension purposes.
  • the pressure acts on a piston or the like which presses the fins outwards.
  • the present invention is based on the new concept that it is possible to extend fins placed on edge without the use of either springs, pistons or lifting surfaces. More precisely, the inventive concept lies in a trapping of the propellant gases between the fins, and then in a sudden release of the trapped propellant gases, such that the entire surface of both sides of the fins is subjected to the out-rushing propellant gases which, thereby, jerk with them the fins because of the assisting frictional force.
  • the space between the side surfaces of adjacent fins is during the passage of the projectile through the barrel at least partially open to the rear, permitting access by the propellant charge gases to the said space such that the entire surface of both sides of the fins is subjected to the propellant charge gases, said space being at the front at least partially sealed in respect to the surrounding atmosphere by means of a projectile girdle or guide pad arranged in front of the fins, said girdle or pad thereby trapping the propellant charge gases in the said space, whereby the passage of said projectile girdle or pad past the barrel muzzle results in the trapped propellant charge gases in the said space rushing outwards to the atmosphere surrounding the barrel and thereby jerking with them the fins into the extended position because of the assisting frictional force which is generated when the propellant charge gases pass along the surfaces of the fins.
  • Figure 1 shows a projectile 2 inserted in a barrel 1 which via a conventional girdle 3 is attached to a cartridge case 4 containing a propellant charge 5.
  • the barrel 1 can be either smooth or rifled and forms part of a weapon which is not shown, e.g. a mortar.
  • the projectile 2 has a rear section 6 which extends into the sleeve 4 up to the propellant charge 5. At its rear end the rear section 6 is provided with six fin attachments 7 (see Figures 2, 7 and 8), in each of which an extended fin 8 which is located on edge against the rear section 6 is rotatably mounted around a pivot pin 9 which is shown schematically.
  • the pivot pin 9 are provided with friction-reducing devices in the form of teflon washers 10 so as to increase the swivel capacity of the fins. It is also feasible to employ other types of friction-reducing devices. For drafting purposes the teflon washers 10 are illustrated only in Figure 7 and then only in one of the fin attachments 7.
  • the fins 8 taper to the rear, so that a wedge-shaped gap 11 is formed between the rear section 6 and the edge 12 of the fins facing the projectile axis.
  • the space 13 between the fins 8 is open at the back towards the propellant charge 5, as can be best seen from Figure 4.
  • propellant charge gases are produced which attempt to discharge the projectile 2.
  • the propellant charge gases fill on the one hand the space 13 between the fins and secondly the wedge-shaped gap 11.
  • the propellant charge gases overcome the resistance to release of the girdle 3, the projectile moves out of the barrel 1 (on the left in Figure 1).
  • the girdle 3 also performs a sealing function in that it permits only a negligible leakage of propellant charge gases to the atmosphere surrounding the barrel.
  • the fins 8 have their centre of gravity G closer to the projectile axis than the centre of rotation 9 of the fins, so that the acceleration forces on the projectile during its discharge bring about a moment which attempts to hold in the fins 8 during passage through the barrel. This location of the centre of gravity is particularly advisable for rotating projectiles.
  • the fins 8 can be skewed at a predetermined twist angle v as so as to maintain or bring about a desired degree of rotation.
  • Figures 7 and 8 show how the fins 8 are mounted in oblique grooves 14 in the fin attachment 7.
  • the rear section 6 has a supporting heel 15 on the skewed side of each fin 8 which prevents the fins being deformed as a result of the accelerational forces to which it is subjected during its passage through the barrel.
  • Such supporting heels can possibly be arranged on both sides of the fins.
  • this support function can be provided by grooves in the rear section 6.
  • FIG. 2 illustrates a second embodiment of the invention which in principle differs from the embodiment shown in Figure 1 only in that the rear section of the projectile 2 is replaced by a guidance mechanism tube 16, shown partially in section, which tapers away forwards and which is open at the rear and which at the front by means for example of a screw connection is fastened to a centrally arranged heel 17 at the rear end of the projectile 2.
  • the interior of tube 16 by this means forms a chamber 18 which is open rearwards towards the propellant charge 5.
  • the tube 16 is provided with six longitudinal slots 19 through which the fins 8 can be partially introduced, as indicated by the dashed edge lines 12. Here the slots 19 provide support for the fins during the passage of the projectile through the barrel.
  • the chamber 18 and the space 13 between the fins 8 is filled by the propellant charge gases from the propellant charge 5. This ensures firstly that a larger quantity of gas passes along the wind surfaces of the fins 8 as the gases rush out to the surrounding atmosphere, and secondly that the gases enclosed in the chamber 18 during their outward rushing motion bring about a pressure which is orientated directly towards the edge 12 of the fins 8 which increases the force which extends the fins.
  • the chamber 18 and the space 13 between the fins 8 are both open at the rear.
  • the chamber 18 can be sealed at the rear whilst the space 13 is open at the rear.
  • the slots 19 are so dimensioned that they permit a flow of gas from the space 13 to the chamber 18 even when the fins 8 are introduced into the slots 19.
  • the embodiment illustrated in Figure 3 differs from the embodiment shown in Figure 2 in that the conically-tapered, slotted guidance mechanism tube 16 is replaced by a guidance mechanism tube 20 of uniform thickness, the interior of which forms a cylindrical chamber 18a and which instead of slots has two apertures 21 all the way through, these being circular in the embodiment illustrated, located in the centre of each fin 8.
  • the apertures 21 have roughly the same dimensions as the thickness of the fins 8.
  • the propellant charge gases in the tube 20 bring about a concentrated compressive force on the edge 12 on the fins 8 which faces the projectile axis, so that a particularly high force is obtained which tends to extend the fins.
  • the rear section 6 is, possibly via a strap or girdle which is not shown, and preferably exhibiting leakage, fastened into a cartridge case 4 with propellant charge 5.
  • the rear section 6 and the tube 25 have a diameter which is somewhat smaller than the barrel 1, so that a ring-shaped gap 26 is formed between them.
  • the tube 24 is provided with a strap or girdle 27.
  • the fixed pivot of the fins is located at the rear end of the fins, as viewed in the retracted position of the fins.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Toys (AREA)
  • Saccharide Compounds (AREA)

Claims (8)

1. Ensemble d'ailettes stabilisatrices pour projectile (2) destiné à être tiré par un canon (1) sous l'action de gaz de charge propulsive, comprenant un ensemble d'ailettes allongées (8) montées en rotation par une extrémité et disposées de façon que, pendant le passage du projectile dans le canon (1), ces ailettes (8) se trouvent dans la position rétractée pour laquelle elles se placent sur le bord, parallèlement les unes aux autres, et essentiellement dans le sens de la longueur du projectile (2), ensemble caractérisé en ce que l'espace (13) compris entre les surfaces latérales d'ailettes adjacentes (8), est au moins partiellement ouvert vers l'arrière pendant le passage du projectile (2) dans le canon (1), en permettant ainsi l'accès d'une partie des gaz de charge propulsive dans l'espace (13) de façon que toute la surface des deux côtés des ailettes soit soumise aux gaz de charge propulsive, cet espace (13) étant, au moins partiellement, fermé de manière étanche à l'avant, par rapport à l'atmosphère environnante, par une ceinture de projectile (3) ou un tampon de guidage disposé en face des ailettes, cette ceinture ou ce tampon permettant ainsi de piéger les gaz de charge propulsive dans cet espace (13) de façon que, lorsque la ceinture ou tampon du projectile (2) passe au delà de la gueule du canon, les gaz de charge propulsive piégés dans l'espace (13) se précipitent vers l'extérieur, dans l'atmosphère entourant le canon (1), en entrainant ainsi avec eux les ailettes (8) en position déployée, du fait de la force de frottement d'entrainement produite lorsque les gaz de charge propulsive passent le long des surfaces des ailettes.
2. Ensemble selon la revendication 1, caractérisé en ce que le pivot fixe (9) des ailettes se place à l'extrémité arrière des ailettes (8) vues dans la position rétractée de ces ailettes (8).
3. Ensemble selon l'une quelconque des revendications 1 et 2, caractérisé en ce que les ailettes (8) en position rétractée, ont leur centre de gravité (G) plus proche de l'axe du projectile que du pivot fixe (9) des ailettes, de sorte qu'un moment est produit par les forces d'accélération appliquées au projectile (2), ce moment tendant à retenir les ailettes (8) pendant le passage dans le canon.
4. Ensemble selon l'une quelconque des revendications 1 à 3, caractérisé en ce que les ailettes (8) peuvent tourner autour d'un pivot (9) muni de dispositifs anti-friction (10) constitués par exemple par des rondelles de Téflon, de manière à augmenter la possibilité de pivotement des ailettes (8).
5. Ensemble selon l'une quelconque des revendications 1 à 4, caractérisé en ce que les ailettes (8) sont montées en biais par rapport à l'axe du projectile, sous un angle d'inclinaison prédéterminé (v).
6. Ensemble selon la revendication 5, caractérisé en ce que l'effet de biais est obtenu en montant les ailettes (8) dans des rainures (14) formant avec l'axe du projectile un angle correspondant à l'angle d'inclinaison en biais (v).
7. Ensemble selon l'une quelconque des revendications 5 et 6, caractérisé en ce que les ailettes (8) en position rétractée, reposent contre au moins un talon de support (15) ou analogue.
8. Ensemble selon l'une quelconque des revendications 1 à 7, caractérisé en ce qu'un tube cylindrique (25) entoure concentriquement l'espace (13) entre les ailettes (8), de façon que la génératrice du tube (25) soit munie de fentes (24) présentant au moins la même longueur que les ailettes (8), et que les fentes (24) soient placées de façon que les ailettes (8) puissent se déployer entre elles.
EP82109120A 1981-10-08 1982-10-02 Ailettes stabilisatrices pour projectile Expired EP0076990B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8105952A SE428058B (sv) 1981-10-08 1981-10-08 Styrverk for projektil
SE8105952 1981-10-08

Publications (3)

Publication Number Publication Date
EP0076990A2 EP0076990A2 (fr) 1983-04-20
EP0076990A3 EP0076990A3 (en) 1983-05-18
EP0076990B1 true EP0076990B1 (fr) 1986-02-19

Family

ID=20344732

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82109120A Expired EP0076990B1 (fr) 1981-10-08 1982-10-02 Ailettes stabilisatrices pour projectile

Country Status (5)

Country Link
EP (1) EP0076990B1 (fr)
DE (1) DE3269205D1 (fr)
FI (1) FI823432L (fr)
NO (1) NO149942C (fr)
SE (1) SE428058B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6164594A (en) * 1997-10-08 2000-12-26 Etienne Lacroix Tous Artifices S.A. Device for braking the fall of a load

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL72000A (en) * 1984-06-04 1989-09-10 Israel State Projectile stabilization system
SE444612B (sv) * 1984-12-13 1986-04-21 Ffv Affersverket Styrverk for utfellning av fenor hos projektil
SE518654C2 (sv) * 2000-07-03 2002-11-05 Bofors Defence Ab Sätt och anordning vid artilleriprojektiler
SE518656C2 (sv) * 2000-07-03 2002-11-05 Bofors Defence Ab Fenstabiliserad artillerigranat

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1405276A (en) * 1918-07-10 1922-01-31 John T Careaga Expanding projectile
NL155094B (nl) * 1969-07-15 1977-11-15 Foersvarets Fabriksverk Besturingsbuis voor een niet-rondtollend projectiel.
DE2721536A1 (de) * 1977-05-13 1978-11-16 Brunsch Kurt Projektil mit leitflaechen

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6164594A (en) * 1997-10-08 2000-12-26 Etienne Lacroix Tous Artifices S.A. Device for braking the fall of a load

Also Published As

Publication number Publication date
EP0076990A3 (en) 1983-05-18
DE3269205D1 (en) 1986-03-27
NO149942B (no) 1984-04-09
SE8105952L (sv) 1983-04-09
FI823432A0 (fi) 1982-10-08
FI823432L (fi) 1983-04-09
NO823362L (no) 1983-04-11
SE428058B (sv) 1983-05-30
EP0076990A2 (fr) 1983-04-20
NO149942C (no) 1984-07-18

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