EP0210732A1 - A balistic body stabilized by flexible fins - Google Patents
A balistic body stabilized by flexible fins Download PDFInfo
- Publication number
- EP0210732A1 EP0210732A1 EP86304396A EP86304396A EP0210732A1 EP 0210732 A1 EP0210732 A1 EP 0210732A1 EP 86304396 A EP86304396 A EP 86304396A EP 86304396 A EP86304396 A EP 86304396A EP 0210732 A1 EP0210732 A1 EP 0210732A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- fin
- projectile
- fins
- connecting member
- balistic
- 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.)
- Granted
Links
Images
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
- F42B10/04—Stabilising arrangements using fixed fins
- F42B10/06—Tail fins
Definitions
- the present invention concerns the stabilization of flying ballistic bodies such as missiles, rockets and bombs, whether self-propelled or not.
- flying ballistic bodies such as missiles, rockets and bombs, whether self-propelled or not.
- projectiles it being understood that this term refers to fin-stabilized projectiles.
- the invention concerns an improvement in the aerodynamic stabilization of projectiles.
- the aerodynamic stability is one of the main considerations in the design of projectiles, whether launched from landborne, seaborne or airborne launchers or, whether dropped from an aircraft.
- Conventionally aerodynamic stability is achieved by means of stabilizing fins and the larger the surface of the stabilizing fins the better the aerodynamic stability.
- geometric constraints which restrict the space available for launching. For example, in the arming of fighter aircraft, the geometry of the aircraft has to be taken into account; or in case of landborne or seaborne launchers the design of the latter must be considered. In consequence of this, restrictions are put on the span of the stabilizing fins, which restrictions are incompatible with considerations of stability.
- a further drawback inherent in large size stabilizing fins, whether static or of the popout type, is the fact that the larger the diameter of a flying projectile the easier becomes its detection by radar.
- each fin is connected to the body by a twistable connecting member, the location of connection of each fin being rearward of the aerodynamic centre thereof.
- the connecting members may, for example, be in form of torsion bars or helical springs and may be made of metal or of suitable plastic material.
- the projectile diagrammatically illustrated in Fig. 1 comprises a body 1 having at its rear a number of stabilizing fins 2 each connected to body 1 by means of a helical spring 3.
- Fig. 2 the fraction of the body 1 shown in Fig. 1 is signified by the longitudinal axis 1'.
- the point CGB shown on line l' signifies the centre of gravity of the body.
- the point CGP on fin 2 signifies the centre of gravity of the fin and the point AC the aerodynamic centre thereof.
- the projectile moves at an angular velocity q and at a translatory velocity v with an angle of attack a formed between the trajectory and the axis 1' which means that the projectile oscillates about its theoretical trajectory.
- the angle of attack a,each stabilizing fin 2 is deflected by being turned around the spiral spring 3 by which it is connected to body 1 forming with the axis of the latter an angle 6.
- the oscillation of the projectile about the trajectory is gradually attenuated which means that the angle of attack a is diminished, whereby in turn the deflection angle 6 of the fins is equally diminished.
- Fig. 3 there are shown two attenuation curves of the oscillations of a fin stabilized projectile.
- the drawn out curve shows the attentuation of a projectile with twistably connected fins according to the invention
- the dashed curve shows the attenuation of a projectile having the same geometry and flying under the same conditions with rigidly connected fins.
- the curves show the reduction of the angle of attack a as a function of time and while the drawnout curve shows that with a projectile according to the invention the angle of attack a diminishes rapidly and after three seconds is reduced to less than half the original, the attenuation of the angle of attack a with a conventional missile with rigidly connected stabilizing fins of the same size and geometry, is much slower.
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)
- Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
- Finger-Pressure Massage (AREA)
- Arc-Extinguishing Devices That Are Switches (AREA)
- Non-Metallic Protective Coatings For Printed Circuits (AREA)
- Polishing Bodies And Polishing Tools (AREA)
- Formation Of Insulating Films (AREA)
- Professional, Industrial, Or Sporting Protective Garments (AREA)
- Motor Or Generator Cooling System (AREA)
Abstract
Description
- The present invention concerns the stabilization of flying ballistic bodies such as missiles, rockets and bombs, whether self-propelled or not. In the following all such flying ballistic bodies will be referred to for short as "projectiles", it being understood that this term refers to fin-stabilized projectiles.
- More specifically the invention concerns an improvement in the aerodynamic stabilization of projectiles.
- The aerodynamic stability is one of the main considerations in the design of projectiles, whether launched from landborne, seaborne or airborne launchers or, whether dropped from an aircraft. Conventionally aerodynamic stability is achieved by means of stabilizing fins and the larger the surface of the stabilizing fins the better the aerodynamic stability. However, there exist geometric constraints which restrict the space available for launching. For example, in the arming of fighter aircraft, the geometry of the aircraft has to be taken into account; or in case of landborne or seaborne launchers the design of the latter must be considered. In consequence of this, restrictions are put on the span of the stabilizing fins, which restrictions are incompatible with considerations of stability.
- It thus occurs quite often that projectiles are developed which are insufficiently stabilized with the result that the ballistic performance of such projectiles is highly sensitive to atmospheric interferences and geometric tolerances which in turn results in inaccurate performance expressed in terms of high dispersion.
- It has already been proposed to overcome .hese defects by means of popout stabilizing fins which merge out of the body of the projectile after its launching but this solution turned out to be complicated and unreliable and to cause an undesired increase of the body weight of the projectile.
- Another proposed solution for improving the aerodynamic stability of projectiles is to shift the centre of gravity forward. However this solution requires the addition of considerable dead weight at the front part of the projectile which reduces the payload for a given propulsion.
- A further drawback inherent in large size stabilizing fins, whether static or of the popout type, is the fact that the larger the diameter of a flying projectile the easier becomes its detection by radar.
- It is accordingly the object of the present invention to overcome the above-described deficiencies by providing a new type of fin stabilization for projectiles.
- In accordance with the present invention there is provided a fin stabilized projectile in which each fin is connected to the body by a twistable connecting member, the location of connection of each fin being rearward of the aerodynamic centre thereof.
- It has been found in accordance with the present invention that projectiles with twistably connected fins have a significantly larger stabilizing effect than rigidly connected fins of the same size and geometry. In flight, when the projectile oscillates about its theoretical trajectory in consequence of atmospheric interferences, the twistably connected fins are deflected out of their rest position whereby the oscillation of the projectile is automatically attenuated. The extent to which the connecting members can be twisted can be determined empirically for each specific design.
- The connecting members may, for example, be in form of torsion bars or helical springs and may be made of metal or of suitable plastic material.
- The invention will now be described, by way of example only, with reference to the accompanying drawings in which:
- Fig. 1 is a fragmentary diagrammatic elevation of a projectile with twistably connected stabilizing fins according to the invention;
- Fig. 2 shows in a diagrammatic manner the flight stabilizing effect of twistably connected fin according to the invention; and
- Fig. 3 is a comparative oscillation attenuation diagram.
- The projectile diagrammatically illustrated in Fig. 1 comprises a body 1 having at its rear a number of stabilizing
fins 2 each connected to body 1 by means of ahelical spring 3. - In Fig. 2 the fraction of the body 1 shown in Fig. 1 is signified by the longitudinal axis 1'. The point CGB shown on line l' signifies the centre of gravity of the body. The point CGP on
fin 2 signifies the centre of gravity of the fin and the point AC the aerodynamic centre thereof. The projectile moves at an angular velocity q and at a translatory velocity v with an angle of attack a formed between the trajectory and the axis 1' which means that the projectile oscillates about its theoretical trajectory. In consequence the angle of attack a,each stabilizingfin 2 is deflected by being turned around thespiral spring 3 by which it is connected to body 1 forming with the axis of the latter an angle 6. As a result of the deflection of the stabilizingfins 2 the oscillation of the projectile about the trajectory is gradually attenuated which means that the angle of attack a is diminished, whereby in turn the deflection angle 6 of the fins is equally diminished. - In Fig. 3 there are shown two attenuation curves of the oscillations of a fin stabilized projectile. The drawn out curve shows the attentuation of a projectile with twistably connected fins according to the invention, and the dashed curve shows the attenuation of a projectile having the same geometry and flying under the same conditions with rigidly connected fins. The curves show the reduction of the angle of attack a as a function of time and while the drawnout curve shows that with a projectile according to the invention the angle of attack a diminishes rapidly and after three seconds is reduced to less than half the original, the attenuation of the angle of attack a with a conventional missile with rigidly connected stabilizing fins of the same size and geometry, is much slower.
- The invention is further illustrated by the following example:
- For imparting a satisfactory aerodynamic stability to a projectile weighing 200 kg. having a diameter of 40 cms. and being 4 m. long and flying at a low altitude at a velocity of 250 m/sec., conventional rigidly connected fins are required having a span of 70 cm. If, however, the fins are twistably mounted in accordance with the invention using a torsion bar of a hardness of 2,000 kg and each mounted 10 cm. sec behind the aerodynamic centre of the stabilizer, the surface of the fins can be reduced by 20% as compared to rigidly connected stabilizers of the same size and geometry. Such a reduction is of great value, for example, for air to ground bombs mounted on and launched from the lower face of the wings of an aircraft.
- For further comparison, if the surface area of rigidly connected stabilizing fins were reduced by 20% the stability would be reduced four times and such a missile would perform inaccurately.
- The features disclosed in the foregoing description, in the following claims and/or in the accompanying drawings may, both separately and in any combination thereof, be material for realising the invention in diverse forms thereof.
Claims (5)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT86304396T ATE50360T1 (en) | 1985-06-27 | 1986-06-09 | BALLISTIC BODY STABILIZED BY COMPLIANT FINS. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IL75653A IL75653A (en) | 1985-06-27 | 1985-06-27 | Ballistic body stabilized by deflectable fins |
IL75653 | 1985-06-27 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0210732A1 true EP0210732A1 (en) | 1987-02-04 |
EP0210732B1 EP0210732B1 (en) | 1990-02-07 |
Family
ID=11056028
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP86304396A Expired - Lifetime EP0210732B1 (en) | 1985-06-27 | 1986-06-09 | A balistic body stabilized by flexible fins |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0210732B1 (en) |
AT (1) | ATE50360T1 (en) |
DE (1) | DE3668987D1 (en) |
IL (1) | IL75653A (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2393604A (en) * | 1943-02-10 | 1946-01-29 | William F Berger | Bomb stabilizer |
US2584826A (en) * | 1946-05-31 | 1952-02-05 | Gulf Research Development Co | Aerodynamic surface for dirigible bombs |
US4198016A (en) * | 1978-06-12 | 1980-04-15 | The United States Of America As Represented By The Secretary Of The Navy | Floating canard with geared tab |
US4351503A (en) * | 1975-02-03 | 1982-09-28 | Mordeki Drori | Stabilized projectiles |
-
1985
- 1985-06-27 IL IL75653A patent/IL75653A/en not_active IP Right Cessation
-
1986
- 1986-06-09 DE DE8686304396T patent/DE3668987D1/en not_active Expired - Lifetime
- 1986-06-09 EP EP86304396A patent/EP0210732B1/en not_active Expired - Lifetime
- 1986-06-09 AT AT86304396T patent/ATE50360T1/en not_active IP Right Cessation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2393604A (en) * | 1943-02-10 | 1946-01-29 | William F Berger | Bomb stabilizer |
US2584826A (en) * | 1946-05-31 | 1952-02-05 | Gulf Research Development Co | Aerodynamic surface for dirigible bombs |
US4351503A (en) * | 1975-02-03 | 1982-09-28 | Mordeki Drori | Stabilized projectiles |
US4198016A (en) * | 1978-06-12 | 1980-04-15 | The United States Of America As Represented By The Secretary Of The Navy | Floating canard with geared tab |
Also Published As
Publication number | Publication date |
---|---|
IL75653A0 (en) | 1985-10-31 |
ATE50360T1 (en) | 1990-02-15 |
EP0210732B1 (en) | 1990-02-07 |
DE3668987D1 (en) | 1990-03-15 |
IL75653A (en) | 1991-07-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5141175A (en) | Air launched munition range extension system and method | |
US5154370A (en) | High lift/low drag wing and missile airframe | |
US2470120A (en) | Method of bombing from fast moving planes | |
US3935817A (en) | Penetrating spear | |
US4519315A (en) | Fire and forget missiles system | |
US3000597A (en) | Rocket-propelled missile | |
US3964696A (en) | Method of controlling the spin rate of tube launched rockets | |
US5112006A (en) | Self defense missile | |
US3018692A (en) | Rotatable rocket launcher | |
US4337911A (en) | Non-spinning projectile | |
US3048086A (en) | Rocket-bomb firing apparatus | |
US3637167A (en) | Missile steering system | |
EP0210732B1 (en) | A balistic body stabilized by flexible fins | |
US5159151A (en) | Missile nose fairing assembly | |
US3964391A (en) | Dispenser-launched munition with two-stage spin-imparting vanes | |
US5430449A (en) | Missile operable by either air or ground launching | |
RU2327949C1 (en) | Missile | |
EP2329216B1 (en) | Multi-stage hyper-velocity kinetic energy missile | |
RU2064655C1 (en) | Aerodynamic canard configuration guides missile | |
US3434417A (en) | Bomb braking system | |
EP1087201B1 (en) | Method and device for correcting the trajectory of a spinstabilised projectile | |
US6402087B1 (en) | Fixed canards maneuverability enhancement | |
Vergez | Tactical missile guidance with passive seekers under high off-boresight launch conditions | |
US2692094A (en) | Composite aircraft | |
RU2814624C1 (en) | Missile stabilizer |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
17P | Request for examination filed |
Effective date: 19870623 |
|
17Q | First examination report despatched |
Effective date: 19881114 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19900207 Ref country code: BE Effective date: 19900207 Ref country code: AT Effective date: 19900207 Ref country code: IT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRE;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.SCRIBED TIME-LIMIT Effective date: 19900207 Ref country code: LI Effective date: 19900207 Ref country code: SE Effective date: 19900207 Ref country code: CH Effective date: 19900207 Ref country code: FR Effective date: 19900207 |
|
REF | Corresponds to: |
Ref document number: 50360 Country of ref document: AT Date of ref document: 19900215 Kind code of ref document: T |
|
REF | Corresponds to: |
Ref document number: 3668987 Country of ref document: DE Date of ref document: 19900315 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19900609 |
|
EN | Fr: translation not filed | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LU Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19900630 |
|
NLV1 | Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
GBPC | Gb: european patent ceased through non-payment of renewal fee | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Effective date: 19910301 |