Tubular projectile.

PATENT NQ. 86 237

Tubular projectile and its manufacturing process so that

ROYAL ORDNANCE plc, intends to obtain invention privilege in Portugal.

SUMMARY The present invention relates to a tubular projectile and its manufacturing process suitable for use in training munitions comprising a hollow tube having formed in the rear end of its tubular wall a recess into which a tracer material is inserted.

projectile can be fired by a higher caliber weapon.

Structures for igniting the trace material, directly or indirectly from the gases produced by the burning of the main propelling charge, are described when the projectile is fired from a weapon, for example an applicant's RARDEN weapon.

Suitable tracing materials and techniques for filling said recess with said tracing materials are also described.

<img file="PT86237B_D0001.tif" />

<img file="PT86237B_D0002.tif" />

Figure 1

<img file="PT86237B_D0003.tif" />

009

ROP 0051

The present description refers to tubular projectiles.

UK patent no. No. 1,571,010 to the present applicant discloses a supersonic tubular projectile invented by Abraham Flatau and Ooseph Huerta, which may be used (but not exclusively) in training munitions. For example, the projectile may be incorporated as a sub-caliber component of training munitions with disposable force bands fired by an applicant's 30 mm RARDEN cannon (RARDEN).

The present invention provides a novel tubular projectile which may optionally comprise a beneficial modified form of the projectile described in UK patent no. 1,571,010.

In accordance with the present invention there is provided a tubular projectile comprising a hollow tube having formed in the rear end of its tubular wall a recess into which a tracing material is inserted.

By a tracer material is meant any material that can be incorporated into a projectile for the purpose of tracing or tracking the projectile's path.

Preferably, the recess extends forward from the rear surface of the rear end of the projectile's tudular body. Preferably, the rear surface comprises a flat tubular ring or a tapered surface. When the rear surface is tapered it may extend and taper inward from the rear edge of the projectile, i.e. form a mouth at the rear end of the hollow portion of the projectile tube. Alternatively the fusto-conical surface may be on the outer surface of the projectile tube tapering to the projectile axis to a point behind the projectile.

Preferably, the inner and outer lateral limits of the recess when viewed from the rear end of the projectile are contained in an intermediate region between the diameters

<img file="PT86237B_D0004.tif" />

-367 009

ROP 0051 interior and exterior of the rear surface of the tubular ring, although the tracer insertion recess could comprise substantially the entire rear surface of the projectile.

The recess may comprise an annular cross-sectional recess, the tubular ring of the recess preferably being substantially coaxial with the portion of the projectile in which it is formed.

Alternatively, the recess may comprise one or a plurality of discrete holes extending to the rear wall of the projectile in its rear portion in a direction parallel to the axis of the projectile. The hole or holes may comprise one or more holes of circular cross section or other suitable shape, for example an arcuate shape such as rectangular arcuate or B (for example, as a salt). The holes are preferably arranged in cross section) in a circular formation.

recess may be formed by machining, e.g. drilling at the rear end of the projectile rear wall. As a preferred alternative, the recess is formed by fitting a section of the insert into the inner or outer wall of the projectile at its rear portion whereby the recess is formed as an empty gap between the insert and the rear wall portion. inside or outside of the projectile body at its rear end. For example, the post may be fitted to the rear inner wall of the projectile. The tubular insert may have one or more grooves or an annular recess in its outer surface. Alternatively, or additionally, the rear inner wall of the projectile may be stepped or grooved in the region where the insert is fitted to provide the required recess. The tubular insert preferably has an inner surface (i.e., facing inwardly to the tube axis) that forms a substantially continuous surface with the main inner surface of the projectile body. For example, the inner surface of the projectile body may contain a step against which the insert touches, for example, as a socket.

009

RCP 0051

<img file="PT86237B_D0005.tif" />

-4 interference or by a sizing agent.

Where said insert contains one or more grooves or an annular recess for receiving the tracing material, the tracing material may be applied to the insert prior to insertion of the insert into the projectile.

Alternatively, said insert may be fitted as a collar to the rear end of the projectile in a suitable recess having a depth region increasing to the rear end of the projectile, the tracing material located in the recess region having depth increased into the part. false. Preferably, the outer surface of the insert and the outer surface of the projectile body forward of the insert provide a substantially continuous surface.

The present invention provides highly convenient and advantageous techniques for incorporating a tracer material, for example a tracer composition, into ammunition incorporating a tubular projectile without substantially affecting the aerodynamic properties of the projectile.

tracing material inserted into said recess in the projectile according to the present invention may be any known tracing material. It may conveniently be provided as one or more flexible lengths of tracing material contained in an inert flexible sleeve, for example made of malleable metal such as lead, lead and antimony alloy, copper, aluminum or a recessed plastic material.

The tracing material provided in this form may be sealed in the recess by any known sizing agent, for example a suitable epoxy resin inside and / or in the recess outlet. Alternatively, the tracing composition may be extruded, compressed or molded directly into the recess.

Tracer material incorporated into the projectile according to the present invention allows the projectile path to be followed. The tracer composition may be a composition that emits strong visible light when ignited. Could

ORIGINAL BAD · - .. _

<img file="PT86237B_D0006.tif" />

7 009

ROP 0051 however is a composition that is a strong smoke emitter or an infrared radiation emitter (which may, for example be followed by an infrared detector) or a material that strongly reflects radio or microwave frequencies, for example to radar tracking.

For example, when the tracer material comprises a visible light emitter it may comprise a pyrotechnic or chemiluminescent material. Many such materials which may be used as pyrotechnic materials are well known to those skilled in the projectile field. For example, such compositions may comprise a metal fuel such as magnesium powder, aluminum, titanium or zirconium and an energy oxidant such as an inorganic nitrate or perchlorate, for example ammonium, barium or strontium, optionally with a polymeric antisense. for example polyester or polyurethane.

Suitable specific examples of pyrotechnic tracing compositions include compositions provided commercially by the present applicant under the designations SR889 and SR390B.

When the projectile according to the present invention incorporates a tracer material into an annular cross-sectional recess, it has been found that an advantageous technique for filling the recess with the tracer material comprises the use of a flexible cylindrical bearing of a poly-bonded pyrotechnic composition. = ro to fill the recess.

A composition suitable for use in the aforementioned flexible sleeve comprises a metal fuel and one or more rods having a oxidizing and flexifying binder. A suitable composition comprises 30 to 60% by weight of magnesium, 35 to 50% by weight of polytetrafluoroethylene and 5 to 25% by weight of a rubber type binder. A rubber-type binder is a vinylidene-fluoridene and hexafluoropropylene copolymer.

A preferred composition for use in the aforementioned flexible sleeve comprises 48 wt% magnesium, 35 wt% polytetrafluoroethylene and 17 wt% vinylidene fluoridene and hexafluoropropylene copolymer.

ORIGINAL BAD

.. —í

<img file="PT86237B_D0007.tif" />

Ú09

RCP 0051

The above-mentioned flexible sleeve may be produced by mixing the ingredients together in powder or particulate solids in the presence of a solvent such as acetone or ethyl acetate to form a processable soft dough. This dough is then molded, compressed or extruded into sheets. □ solvent is allowed to evaporate from the leaves by drying in a heated atmosphere. After drying the resulting sheets which are flexible are cut to size and then wrapped around a cylindrical mold to produce the required sleeve as a preform for insertion into a projectile.

Alternatively the sleeve may be formed by direct extrusion of a tubular form from an extruder. It may for example be convenient to extrude elongated tubes and then cut these tubes to size to form sleeves prior to drying.

A sleeve formed in one of the methods described above may be recessed into a tubular projectile by insertion using a suitable guide tool followed by consolidation using a plate driven by a hydraulic press. In fact, however, an extruded sleeve can be extruded directly into the recess.

A further alternative process for filling the projectile recess with a sleeve of tracer material is to provide the projectile in a form in which the projectile collar-shaped outer ring around the recess is tapered, because the recess has an area in larger cross section at its outer end. 0 The recess may then be filled with tracer material, in one of the ways described above, after evaporation of the solvent, it may be consolidated by stamping down the tapered outer surface of the projectile, for example by pushing the projectile through a mold or using it. rollers or any other well-known stamping technique, whereby the final shape required for the projectile's outer profile with the tracing material inserted in its recess is obtained.

When a tubular projectile is used in conjunction with

UNIULNAL BAU

<img file="PT86237B_D0008.tif" />

009

ROP 0051

A forcing belt according to the present invention the tubular projectile preferably has in cross section in a plane containing the projectile axis a front portion with an inner surface conically converging in a direction in front of the rear end of the projectile. , an intermediate portion with a substantially constant diameter inner surface and a rear portion with an inner surface conically diverging in a direction in front of the rear end of the projectile. The material from which the tubular projectile body is made in accordance with the present invention is not critical although high strength metal materials are preferred. 0 The material may, for example, be aluminum alloy, steel or in armor piercing applications, denser metal such as tungsten alloy. In general, the general shape of the projectile in accordance with the present invention is substantially the same as that described and claimed in UK Patent. 1,571,010 except that the tapered stern rear end of that projectile is replaced by the flat or fusto-scenic annular surface as specified above.

The tubular projectile according to the present invention may be a sub-component of a disposable forcing belt ammunition, for example as described in UK patent no.

571 010. The forcing strap may be made of a plastic material or a light metal, for example aluminum alloy. An actuation belt that provides rotation due to the barrel barrel ribs to stabilize the projectile in flight may be provided, for example, on the outer surface of the force belt.

Alternatively the projectile according to the present invention may be a full gauge projectile and may, for example, be provided with a drive belt on its outer surface.

A base element, for example an impeller or an arrester / shutter may be provided to transmit the main firing forces to the rear end of the projectile and to its forcing belt, if included. The base element may be, for example, made of ORIGINAL plastic material.

009

ROP 0351

<img file="PT86237B_D0009.tif" />

-8c high strength such as polycarbonate material.

I) Although the tracer material incorporated in the projectile according to the present invention comprises a composition which is ignited to emit visible light during the projectile, the tracing composition may be directly or indirectly ignited when the propelling charge provided for projectile firing starts. Preferably, the base element, for example used as an impeller in conjunction with the projectile, has a groove, for example an annular groove, in front of the recess in the projectile incorporating the tracing composition to facilitate such inflammation. Preferably the slot is sealed by the rear surface of the rear end of the projectile into which said recess is incorporated. Such a groove allows ignition of the tracer composition without expulsion of propellant gas through the main opening of the hollow part of the projectile.

In a structure for indirect ignition of the tracing composition, an igniter located behind the projectile, for example housed in the base element substantially at the bottom of the projectile, may be of a known type which is arranged to be initiated by the force of ignition. recoil or rotation of the projectile, for example by pressure or impact on a suitable composition for example, an impact sensitive composition comprising lead azide. This device may be conveniently arranged to provide, when ignited, hot gas for the tracing composition. For example, the igniter may be located in a cavity in a base element having one or more bleed channels extending from the cavity to the surface of the base element, for example in said groove, in a region adjacent to the base. recess of the projectile in which the tracing composition is incorporated. When the impeller in this form of the invention has an annular groove in front of the recess incorporating the tracing composition the hot gas exits this recess to ignite the tracing composition.

In a direct structure for igniting the tracing composition, hot gas obtained from ignition of the propelling charge η λ

009

ROP 0051

<img file="PT86237B_D0010.tif" />

The main can be bled through a narrow bleed hole or channel in the base element into the slot in the base element in front of the recess in which the tracing composition is. It's incorporated.

In this way the tracing composition can be ignited while restricting the increase in gas pressure behind the projectile. An explosion septum or disc or tubular ring may be provided in the gas circuit to retard the flow of hot gas to the tracing composition, thereby retarding the undesirable increase in gas pressure at the rear of the projectile.

Embodiments of the present invention will now be described by way of examples with reference to the accompanying drawings, in which:

fig. 1 is a cross-sectional side view of a tubular projectile embodying the present invention;

fig. 2 is an end cross-sectional view of an alternative tubular projectile embodying the present invention;

Figs. 3, 4 and 5 are cross-sectional side views of alternative tubular projectiles embodying the present invention;

fig. 6 is a partial cross-sectional side view of a structure embodying the present invention, comprising a tubular projectile in conjunction with its associated drive components;

Figures 7 and 3 are cross-sectional side elevations of alternative base members for use in structures embodying the present invention, comprising a tubular projectile together with an associated impeller base;

fig. 9 is a cross-sectional side elevation of a projectile as shown in FIG. 1 during manufacture;

fig. 10 is a cross-sectional side elevation of an alternative tubular projectile embodying the present invention.

r ·. ·

<img file="PT86237B_D0011.tif" />

009 RDP 0051

-10 In fig. 1, a tubular projectile comprising a front portion 1, a middle portion or body 3 and a rear portion 5 is shown. In the front portion 1, the inside diameter conically converges in a direction in front of the rear portion 5. In the front portion average 3 the inner diameter is constant. In the rear portion the inner diameter conically diverges in a frontal offset direction from the front portion 1. The rear portion 5 has a flat annular rear surface 7. The outer surface of the front portion 1 has a convergent section encontra which meets the inner surface at a tapered annular front edge 9. The outer surface has a constant diameter at the middle portion 3 and the rear portion 5 behind the convergent section Θ. An annular cross-sectional recess 11 is formed in the rear portion 5. This extends from the rear surface 7 inwards to occupy part of the middle portion 3 in a direction parallel to the projectile axis. 0 recess 11, which may be machined, is filled with a tracing composition in one of the ways described above.

In the alternative embodiment shown in fig. 2, recess 11 is replaced by individual holes 11a which may be formed, for example, by machining and filled with tracer material in one of the ways described above.

In the alternative embodiment shown in fig. 2, the recess 11 is replaced by individual holes 11a which may be formed, for example, by boring and filled with tracing material in one of the ways described above.

In fig. 3, parts similar to those shown in figs. 1 and 2 carry the same numeric references. In the case of the embodiment of fig. 3, the annular recess 11 extends again from the rear surface 7 through the rear portion 3 in a direction parallel to the projectile axis. However, in this case recess 11 is formed between a post 17 and the lower body wall indicated by the numeral reference 1Θ, forming the remainder of the tubular projectile. The insert may have axial grooves to provide the required recess rather than to form this as an empty gap between the original bad insert

0C9

RCPGG 51

<img file="PT86237B_D0012.tif" />

-11and the body of an inner body wall. The inner wall of the body 18 has been machined to form a step 19 to provide recess 15 with the included post 17. The insert 17 abuts an additional step 21 machined to the inner wall of the body 1Θ and has an inner surface that is substantially continuous with that of the inner wall of the body 15 towards the front of the insert 17. The recess 15 is filled with a tracing composition in one of the ways described above.

In fig. 4, parts similar to those shown in fig. 3 carry the same numerical references. In the case of the embodiment of fig. A, the flat annular rear surface 7 shown in fig. 3, is replaced by a fusto-scenic annular rear surface 71. This has the additional advantages of an increased rear area of ​​the tracer-filled recess 11, to increase the burn area of ​​the tracer material, and also a reduced drag on the rear of the projectile. . 0 recess 11 extends parallel inwardly to the projectile axis from surface 71.

In fig. 5, parts similar to those shown in fig. 3 carry the same numeric references. In the case of the embodiment of fig. 5 the rear surface 71 of FIG. A is replaced by a rearwardly inclined fusto-scenic rear surface 72 from which the annular recess 11 extends inwardly.

In an alternate embodiment of the present invention (not shown) in a post piece replacing the post 17 may have axial grooves to provide discrete holes (rather than a tubular ring) into which the tracing material is inserted.

Fig. 6 depicts a structure for firing a tubular projectile embodying the present invention and for igniting the tracing composition by a direct process.

The projectile indicated by the numerical reference 31 may be as shown in FIG. 1 or as shown in fig. 3

The composition of the projectile 31 is indicated by the original numeral reference.

<img file="PT86237B_D0013.tif" />

009

ROP 0051

3. A forcing strap 35 (which may for example be formed in segments in a known manner) is placed around the projectile 31. An driving strap 37 is attached to the outer surface of the forcing strap 35. A Case impeller carrying a shutter 38 is located behind the rear surface of the projectile 31 and forcing strap 35. 0 impeller 39 has an annular channel 41 extending through each other in a direction parallel to the axes of impeller 39 and projectile 31. Channel 41 has three regions namely an annular recess 41a in front of the tracing composition 33, a narrow portion 41b and a wider portion 41c behind the narrow portion 41b. The largest portion 41c houses an annular septum 43.

In operation, base impeller 39 is contained within a cannon in a conventional firing housing (not shown) in front of a known gun propellant (not shown). When the gun is fired the propellant is ignited causing rapid expansion of the gas which is plugged by the shutter 38. The increased pressure causes the projectile 31 and the forcing strap 35 to be driven by the impeller 39 in a forward direction to Out of the cannon. The drive belt 37 engages the gun striations (not shown) to provide rotation to the projectile to maintain projectile stability during flight.

When the pressure of the hot propellant gas produced by the initial combustion of the main propellant charge reaches a limit. The septum 43 explodes, allowing gas to enter channel 41 and reach the tracing composition 33 which thus ignites.

Narrow portion 41b enables this to be achieved without an undesirably high increase in gas pressure behind projectile 31. Such an increase is desirable to prevent gas leakage during separation of projectile 31 from impeller 39 prior to the start of acceleration.

Leaving the cannon's mouth the forcing strap is quickly discarded allowing the projectile 31 to continue to

ORIGINAL BAD

-1367 GC9

RCP 0051

<img file="PT86237B_D0014.tif" />

□ huh. The tracing composition allows the projectile's trajectory to be followed during flight.

In fig. 1 is shown an alternative base impeller 39. In this case, channel 41 (Fig. 4) is replaced by a channel 42 having a narrow portion 42b conically and laterally diverging from a common cylindrical opening 44 housing a cylindrical septum 46. Narrow portions 42b open at its end front to an annular recess 42a similar to recess 41a which is adjacent to the tracing composition 33 (Fig. 3). The operation of the embodiment of fig. 17 is similar to the embodiment of fig. 5

Fig. 8 shows an additional alternative base impeller structure that can be used in conjunction with projectile 31 and the forcing belt 35 shown in fig. 5. In the embodiment shown in fig. 7 an igniter 51 is housed within the base impeller indicated by the numeral reference 50 behind the projectile 31 (fig. 3). A cap 53 with an impact pin is disposed in front of the device 51. An opening 56 behind device 51 leads to an annular recess 55, similar to recess 41a shown in fig. 1 through a narrow annular channel portion 57.

In operation of the structure of fig. 8, cap 53 is retracted by projectile 31 (fig. 3) after firing the cannon, causing its impact pin to initiate device 51. Hot gas produced by initiation of device 51 flows from aperture 56 to recess 55 through the channel portion 57, thereby igniting the tracing composition 33 (fig. 3) adjacent to the recess 55. It will be appreciated that the ignition process of the tracing composition 33 by the base impeller structure of FIG. 7 is an indirect method.

In a further alternative embodiment (not shown) the igniter 51 and the cap 53 may be replaced by a known igniter which is rotationally sensitive and inflamed by the rotation rather than the kickback of the projectile 31.

In an additional embodiment (not shown), an original projector

C09

ROP 0051

<img file="PT86237B_D0015.tif" />

<img file="PT86237B_D0016.tif" />

useful · similar to those shown in figs. 1 or 2 or fig. 3, 4 or 5 may be a full gauge projectile which is fired from a base impeller similar to that shown in fig. 6, 7 or 8 but having a diameter substantially the same as that of the projectile. In this case the drive belt is provided on the outer surface of the projectile.

Fig. 9 shows an example of a projectile as shown in fig. 1 during manufacture. This represents a filling process of the projectiles shown in FIG. 1 and figs. 3 to 5 with tracer material. In this example, the outer ring referenced by 5a in fig. 9, the rear portion 5 around the recess 11 is tapered to its rear surface 7 so that the recess 11, prior to the insertion of its tracing material, has a larger cross-sectional area at its rear (outer) end. than at its front end (inner). A flexible sleeve of tracer material (not shown in fig. 8) manufactured in one of the ways described above is inserted into recess 11 and, after any necessary drying of the tracer material solvent, the ring 5a is stamped down so that the projectile of the shape shown in FIG. 1.

fig. 10 shows an alternative to the structure shown in fig. 3. In the case of the structure of fig. 10, the projectile comprises a front portion 1, a middle portion 3 and a rear portion 5 all similar to those of FIG. 3, but a piece 81 is provided as a collar fitted in a recess 82 in the outer rear wall of the projectile. 0 recess 82 has, extending from step 83 to the rear end of the projectile, an increased spaced region 84 in which the tracing material is inserted into the insert 81.

r bad original

I

009

ROP 0051