US3797359A

US3797359A - Multi-flechette weapon

Info

Publication number: US3797359A
Application number: US00280558A
Authority: US
Inventors: R Mawhinney; A Mccone; A Foote
Original assignee: ME ASS
Current assignee: BAE Systems Integrated Defense Solutions Inc; ME ASS
Priority date: 1972-08-14
Filing date: 1972-08-14
Publication date: 1974-03-19
Anticipated expiration: 1991-03-19

Abstract

A plurality of flechettes are mounted in a casing or sabot at the forward end of a rocket motor which propels itself, the casing and flechettes through a launching tube. The casing or sabot produces the rotation of the rocket within the tube and separates at the muzzle freeing the group of flechettes which are advanced along a trajectory as the rocket motor drags and falls therebehind. The rotation of the group of flechettes causes them to spread horizontally and vertically and when retained in a rectangular group and released with a vertical orientation the progressive spreading of the flechettes covers twice the area horizontally as they do vertically thereby increasing the striking pattern as the flechette group advances along the trajectory. The flechettes have a rodlike body pointed at one end and provided with a plurality of thin vanes at the opposite ends. This permits the flechettes to be compactly grouped into layers from which they expand as they are advanced, as pointed out above.

Description

Unite States atent [191 Mawhinney et a1.

[ MULTl-FLECHETTE WEAPON [75] Inventors: Robert C. Mawhinney, Danville;

Alan L. M'cCone, Jr., San Francisco; Alvin L. Foote, Livermore, all of Calif.

[73] Assignee: ME Associates, San Romon, Calif.

[22] Filed: Aug. 14, 1972 21 Appl. No.: 280,558

[52] US. Cl 89/1.8, 42/78, 89/1816, 89/14 SB, 102/42 C, l02/DIG. 7 [51] Int. Cl F41f 3/04 [58] Field of Search... 89/18, 1.816, 1.817, 145 SB; 102/42 C, 38, DIG. 7; 42/78 Mar. 19, 1974 Primary Examiner-Samuel W. Erigl Attorney, Agent, or Firm-Harness, Dickey & Pierce [57] ABSTRACT A plurality of flechettes are mounted in a casing or sabot at the forward end of a rocket motor which propels itself, the casing and flechettes through a launching tube. The casing or sabot produces the rotation of the rocket within' the tube and separates at the muzzle freeing the group of flechettes which are advanced along a trajectory as the rocket motor drags and falls therebehind. The rotation of the group of flechettes causes them to spread horizontally and vertically and when retained in a rectangular group and released with a vertical orientation the progressive spreading of the flechettes covers twice the area horizontally as they do vertically thereby increasing the striking pattern as the flechette group advances along the trajectory. The flechettes have a rodlike body pointed at one end and provided with a plurality of thin vanes at the opposite ends. This permits the flechettes to be compactly grouped into layers from which they expand as they are advanced. as pointed out above.

11 Claims, 20 Drawing Figures PATENTEBMAR 19 1914 3797.359

SHEEI 1 0F 3 1 g if Z) f/ f/ MULTI-FLECHETTE WEAPON SUMMARY OF THE INVENTION The invention pertains to a multi-flechette weapon embodying a launching tube which may be of any desired shape but herein is illustrated as square in section and twisted 90 within its length of approximately 4 feet. The weapon has a magazine for a plurality of rounds which are automatically fed into the breech of the launching tube where they are fired by any suitable means, herein illustrated as by the use of a percussion cap. The cap fires an igniter which ignites a fast burning propellent contained within the motor of the rocket providing a short burn time which occurs within the length of the launching tube. Burn out within the launching tube is very important since it eliminates the dispersion due to thrust misalignment. The forward end of the rocket has a friable casing pressfitted thereon which is ruptured near the breech of the tube asit is advanced by the motor after the rocket is fired. The casing is split into several sections, herein shown as four in number, which separate at the muzzle of the tube permitting the flechettes to advance as a group. Due to the drag of the motor the group of flechettes advance ahead therefrom along the trajectory on which the tube was aimed.

The 90 rotation of the group of flechettes as they pass through the bore of the launching tube causes them to spread apart as they advance beyond the tube to occupy an area which increases in size as the group of flechettes advances further and further along the trajectory. When the flechettes are mounted in the casing so that on exit they are in a vertical rectangular group, the horizontal spreading will be twice the amount of the vertical spreading so that a wide impact area will be provided at the target zone. This elliptical pattern effect is based on the transverse momentum of each flechette at the instant of exit and release.

The flechettes have a rodlike body which are pointed at the outer end and swaged at the rear end to provide a plurality of thin fins which permits the tight nesting of the flechettes into layers, the one set of fins nesting on pillars or on the fins of the first layer of flechettes. When separated by the rotation of the flechette group, the fins maintain the bodies in parallel relation to each other and to the trajectory. The propellent employed in the motor is extremely fast burning so that the burnout occurs near the muzzle within the launching tube which provides accuracy to the group of flechettes as they leave the muzzle thereof with a muzzle velocity of 2000 feet per second.

BRIEF DESCRIPTION OF THE DRAWINGS 7 Ward end of the casing broken away to show the group of flechettes contained therein;

FIG. 5 is an enlarged rear view of the rocket illustrated in FIG. 3, as viewed from the point 5 thereof;

FIG. 6 is a view of a group of flechettes in a form in which pillars or pedestals are employed for the intermediate group of flechettes which permit the solid grouping thereof;

FIG. 7 is a view of a flechette having flat tops on the fins on which the intermediate group of flechettes are supported thereby eliminating the pedestals;

FIG. 8 is a view of a group of the flechettes which has the fins on the intermediate group supported on the fins of the bottom group;

FIG. 9 is a sectional view of the flechette illustrated in FIG. 7, taken on the line 9- 9' thereof;

FIG. 10 is a sectional view of the flechettes illustrated in FIG. 7 taken on the line 10-10 thereof;

FIG. 11 is a perspective view of a half section of a casing two of which form a container for the flechettes;

FIG. 12 is an enlarged broken sectional view of the structure illustrated in FIG. 1, taken on the line 12-12 thereof;

FIG. 13 is a sectional view of the structure illustrated in FIG. 12, taken on the line 13-13 thereof;

FIG. 14 is a perspective view of the rear end of the casing with the flechettes mounted within a rectangular area thereof;

FIG. 15 is a sectional view of the structure illustrated in FIG. 14, taken on the line 15-15 thereof;

FIG. 16 is a sectional view of the structure illustrated in FIG. 14, taken on the line 16-16 thereof;

FIG. 17 is a view of the structure illustrated in FIG. 11, as viewed within circle 17 thereof;

FIG. 18 is a view of structure similar to that illustrated in FIG. 3, showing another form of rocket;

FIG. 19 is an exploded perspective view of the rocket illustrated in FIG. 18, and

FIG. 20 is a perspective view of a rack for applying pedestals to a supporting plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I, a rocket launching tube 20 has a square tube 21 of substantial length, the one herein illustrated is approximately four feet long. Within the length of the tube a twist is provided of approximately from the breech end to the muzzle end. An open breech 22 is mounted at the rear end of the tube 21 having a releasable magazine 23 mounted thereon. The tube is supported upon a bar 24 having a handle'25 and shoulder pad 26 thereon by which the launching tube is carried and supported. A sling 27 has the forward end mounted on the tube 21 and the rearward end on a band 28 secured to the bar 24. The magazine 23 supports a number of rockets 29 consisting of a motor 31 and a flechette supporting casing 32 forward thereof, as illustrated in FIGS. 2 to 5. The rocket motor 31 is cylindrical in form tapering at 33 to a rear nozzle end 34. The nozzle end 34 is herein illustrated as being provided with a percussion cap 35 although electric and other means may be provided for igniting an igniter charge 36. The igniter charge 36 fires the propellent charge in the motor 31 which is extremely fast burning to have the burning and propelling force occur within the launcher tube 21 as the flechette casing is leaving the muzzle.

The material of the flechette casing must be friable or brittle so that it can be separated into a plurality of sections when leaving the muzzle which will be thrown outwardly by centrifugal or aerodynamic force away from each other and the group of contained flechettes. While other structures and methods could be provided, a casing is herein illustrated, by way of example, which is fractured as it is propelled along the interior of the launching tube into pieces which are readily separated. The flechette casing herein illustrated has a pair of half casing elements 37 which are made of a thin brittle plastic material having side walls 38, a pair of split front wall sections 39, a top wall 41 and a rear wall 42, the latter having a semicylindrical opening 43.

Two of the casing sections are secured together about a group of flechettes upon mating and sealing the side wall edges 44, as illustrated in FIG. 16. The edges 44 have a 90 inner cutout portion 45 forming a semicircular longitudinal recess when the two edges 44 are secured together as by adhesion, heat, sonic or other bonding method. The top wall, as illustrated in FIG. 15, has a longitudinal central semi-cylindrical recess 46 extending therealong adjacent to a notch 47 at the front end which is equal to the thickness of the front wall sections 39 and of a depth to extend to the abutting edges 48 thereof. After the flechettes are mounted within the casing sections 32 or when said sections are assembled thereover after the flechettes have been grouped, the edges 44 are secured together. The rear cylindrical opening 49, as illustrated in FIGS. 13 and 14, is forced over the shouldered end 51 of the motor 31 which is herein illustrated as being made from fiber glass although other material could be employed therefor. The

shoulder extends over the edge of the rear wall 42 with the cylindrical surface of the motor disposed tangent to the four sides of the joined casing elements 37 where outwardly presenting grooves 50 are provided aligned with the inwardly presenting grooves 46 in the casing.

The launching tube 21 has fracturing elements 52 in each of the walls thereof in opposite aligned relation to each other. The elements 52 are herein illustrated, by way of example, as being studs threaded through the wall of the tube and secured in adjusted position by a nut 53. The inner end 54 of the fracturing element projects from the inner face of the tube walls in an amount sufficient to deflect the portions 55 of the casing wall into the recesses 46 therebelow to crack and separate the casing 38 into four separate pieces. The projection of the ends 54 is such as to produce the cracking of the plastic material above the recesses 46 while permitting the grooves 50 of the motor 31 to pass thereby without engagement therewith. In practice the points are adjusted to a desired position and preferably braised or welded thereafter to prevent any change in the position thereof.

After the rocket is fired, the motor 31 advances the casing 32 forwardly in the tube 21 and the inner ends 54 of the fracturing elements 52 separate the casing into four pieces. The shoulder 56 on the motor continues to advance the four casing pieces through the tube to the muzzle end thereof. The burnout occurs before the casing passes from the muzzle end and the four sections thereof are thrown outwardly by centrifugal or aerodynamic force away from the flechettes which are still retained in a compact group. The flechettes being made of metal, have inertia which continues the outward flight thereof as the motor housing drags therebehind. The advancing group of flechettes spread outwardly while being maintained in the direction of flight along the trajectory by the set of vanes thereon.

In FIG. 14, the flechettes are illustrated as being grouped in rectangular form between the inner wall sections 57 which abut each other along lines 58. The rectangular group of flechettes spread outwardly along the horizontal plane substantially twice as fast as they spread out vertically. The horizontal spread at 50 meters is approximately 1.25 meters with the vertical spread approximately 0.62 meters. At meters the horizontal spread is approximately 2.50 meters while the vertical spread is approximately 1.25 meters. At 150 meters the horizontal spread is approximately 3.75 meters while the vertical spread is approximately 1.87 meters. At 200 meters the horizontal spread is approximately 5.00 meters while the vertical spread is approximately 2.50 meters. A muzzle velocity of approximately 2000 feet per second is attained providing a substantial impact of the flechettes at the target area, each flechette having a maximum penetrating ability.

The casing supports approximately flechettes, each of which weighs approximately eight grains making the overall weight of each rocket approximately .4 pounds. It is contemplated that each soldier will carry 33 rounds or a rocket weight of 13 pounds. The launcher tube is approximately 1.57 inches square and weighs approximately four pounds. The 90 turn within the rocket length of 4 feet provides an axial rotation to the casing after it passes the fracturing elements 52 and permits it to follow the twist of the tube and complete the rupture along the lines of the deflected portions 55.

It was pointed out above that any means may be provided for firing the rocket when in the breech of the tube. A pistol grip 59 is supported on the bar 21 having a trigger 61 which fires an electric charge or operates a hammer in the conventional manner to fire the rocket by igniting the igniting charge which ignites the rocket propellent. The hammer necessary to fire the cap in the nozzle end when the rocket is in the breech is not herein illustrated as any hammer and its connection to the trigger known in the art to be suitable may be utilized.

The flechette, as illustrated in FIGS. 6 to 10, has a cylindrical body 62, a pointed end 63 and four vanes 64 at the rear end. The flechette is preferably made from a wire or rod being struck in dies toproduce the four thin right angle vanes 64 and the flattened four sides to form the pointed end 63. Various means may be pro vided for assemblying the flechettes into a compact group. The flechettes illustrated in FIG. 6 have the top of the vanes 65 sloping to the body at 66 and in this arrangement the flechettes group 67 rests on the forward face of the motor 31 while the intermediate group 68 is supported on plastic pedestals 69 adherred to and extending from a plastic plate 70. The group 67 is preferably assembled together first with the second group 68 assembled together and slid downwardly between the body of the flechettes in the group 67. The same end is obtained in the grouping of the rocket illustrated in FIGS. 7 and 8 wherein the upper end of the vanes 64 have flat tops 71 disposed in a plane and onto which the vanes of the upper or intermediate group of flechettes 72 have the vanes 64 rest thereon for supporting the flechettes 72 on the group of flechettes 73 thereby eliminating the pedestals 69. The flechettes may be assembled in each half of the casing 32 or may be assembled on a fixture and have the two sections of the casing slid thereover after which the casing sections are adherred together along the edges 44. After the sections are adherred together with the flechettes grouped therein the end 51 of the motor 31 is forced into the cylindrical opening 49 at the inner end of the assembled casing. The frictional engagement between the casing and the cylindrical end 51 of the motor 31 retains the casing and the group of flechettes in fixed relation to the motor to complete the rocket. It is to be understood that the launching tube has grenade capacity so that the launching tube will have the dual function of rocketlaunching grenades as well as flechettes Referring to FIGS. 18 and 19, a load plate 75 is illustrated as being positioned between the rocket motor 31 and the casing 32. In the embodiment illustrated in FIGS. 1 to 17, the shouldered end 51 of the rocket motor 31 engages the end corner sections 42 to extend over the edge thereof in tangential relation to the outer faces of the side walls 38 of the casing. Because of the brittleness of the material of the casing 32, there is some danger that the rocket motor would rupture the casing due to setback force during thrust and to avoid such a possibility the load plate 75 is employed. The load plate is made of metal and provided with notches 76 at the center of the edges in position to pass over the fracturing elements 52 within the launching tube. The load plate is adherred to the end of the rocket motor and a pedestal plate 77 is adherred to the outer face of the plate in position to frictionally support the casing 32 in a manner as pointed out above in regards to the structure of FIGS. 1 to 17.

The pedestal plate 77 has the pedestals 69 adherred to the supporting plate 81 by the use of the frame 78 illustrated in FIG. 20. The frame has apertures 79 precisely located therein for positioning the pedestal 69 on the plate 81 when being adherred thereto. The exposed face of the plate 81 is covered with an adhesive material and the frame 79 is placed thereover in spaced relation thereto. The pedestals are then inserted in the apertures 79 and retained against the adhesive material on the face of the plate 81 by a pressure plate (not shown) until adherred thereto. The rocket functions in the same manner as that above described when fired within the launching tube, the plurality of the sections 32 are thrown sidewardly of the flechettes which advance along the trajectory ahead of the rocket motor 31, the load plate 75 and pedestal plate 77 which are in unit relation to each other.

We claim:

1. In a multi-flechette weapon, a rocket having a motor, a separable casing on the forward end of the motor containing flechettes, a launching tube having a breach end in which the rocket motor is fired, said launching tube and casing being square in cross section, and

points for fracturing the casing provided at the center of the inner side walls adjacent to the breach end as the casing is advanced therethrough without engaging the wall of the rocket motor.

2. In a multi-flechette weapon as recited in claim 1, wherein said casing has a fracturable line along the center of each of the four sides thereof.

3. In a multi-flechette weapon as recited in claim 1, wherein said launching tube has a longitudinal twist within the length of the launching tube through which the casing passes for turning the rocket motor and casing about the longitudinal axis thereof to provide axial rotation thereto which completes the rupturing of the case into four sections by the time it reaches the tube muzzle end.

4. In a multi-flechette weapon as recited in claim 3, wherein a group of flechettes is assembled in rectangular shape, the centrifugal force thereon after separating from the casing and motor housing causes the flechettes to spread horizontally and vertically.

5. In a multi-flechette weapon as recited in claim 4, wherein the group of flechettes is of rectangular form so as to spread horizontally twice the amount occurring vertically as the group of flechettes advance along the trajectory.

6. In a multi-flechette weapon as recited in claim 3,

-wherein the tube is twisted lengthwise approximately for each 4 feet of length.

7. In a multi-flechette weapon as recited in claim 1, wherein said fracturing points are mounted adjacent to the breech end of the launching tube to permit the casing section to twist as it passes therethrough which completes the rupture of the casing into separate sections.

8. In a multi-flechette weapon as recited in claim 1, wherein the separated sections of the casing are thrown sidewardly of the trajectory by centrifugal or aerodynamic force as the casing passes from the muzzle end of the launching tube.

9. In a multi-flechette weapon as recited in claim 8, wherein the drag on the rocket motor after passing from the tube permits the advancement of the group of released flechettes ahead thereof.

10. In a multi-flechette weapon as recited in claim 1, wherein the propellent in the rocket motor is consumed within the tube about the time the rocket motor leaves the launching tube.

11. In a multi-flechette weapon as recited in claim 1, wherein a load plate is secured to the end of the rocket motor, and a pedestal plate secured to the outer face of the load plate for supporting said casing in a manner to permit it to separate into a plurality of sections when leaving a launching tube.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 359 Dated 1 -(QRobert C. Mawhinney, Alan L. McCone, Jr. and Alvin L. Foote It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Inventor "Alan L. McCone, Jr,i" should be ---Alan I, McCone, Jr.

Assignee "ME Associates" should be --MB Associates--.

Signed and'sealed this 1st day of April 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. ILASON Commissioner of Patents attesting Officer and Trademarks FORM PO-105O (10-69) USCOMM-DC 50375-P59 i U. S. GOVIINNINT PRINTING OFFICE "CI 0-356-834 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION p t 3,797,359 Dated Mar. 719, 1974 -(QRobert C. Mawhinney, Alan L. McCone, Jr. and Alvin L. Foote It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

7 InventorflAlan L. McCone, Jr."" should be ---Alan I. McCone, Jr.-.

Assignee ME Associates" should be --MB Associates-.

Signed and'sealed this 1st day of April 1975.

(SEAL) Attest:

C. Z'fARSHALL DANN RUTH C. ILSON Commissioner of Patents Attesting Officer and Trademarks FORM PO-iOSO (10-69)

Claims

1. In a multi-flechette weapon, a rocket having a motor, a separable casing on the forward end of the motor containing flechettes, a launching tube having a breach end in which the rocket motor is fired, said launching tube and casing being square in cross section, and points for fracturing the casing provided at the center of the inner side walls adjacent to the breach end as the casing is advanced therethrough without engaging the wall of the rocket motor.

6. In a multi-flechette weapon as recited in claim 3, wherein the tube is twisted lengthwise approximately 90* for each 4 feet of length.