GB2377984A

GB2377984A - Stealth protection/armour

Info

Publication number: GB2377984A
Application number: GB0118261A
Authority: GB
Inventors: Jeffrey Flatley
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-07-26
Filing date: 2001-07-26
Publication date: 2003-01-29
Anticipated expiration: 2021-07-26
Also published as: GB2377984B; GB0118261D0

Abstract

Stealth protection/armour in the form of units 17 comprises rigid and/or flexible strip elements 14 that are (inter)connected/suspended at one margin 3 and separated by box sections 15 so as to form a skeletal three-dimensional structure with a base 16 which may be adapted to be fitted to a vehicle with the minimal dimension 2 of each element facing outwardly. Hard facings 18 and/or coloured sleeves 19 may be fitted on the free edges. Additionally, side surfaces 20 may have radar absorbent material and/or the spaces between the elements 14 may include laser absorbent/dispersants 21 so as to alter/distort the radar or thermal image of the vehicle to which they are fitted. The edges of elements 14 may be tapered, curvilinear or straight (see Figs 6-8).

Description

STEALTH PROTECTION/ARMOUR This invention relates to stealth protection/armour for military use and in particular for application on board military vehicles.

Stealth in relation to military vehicles is often limited to camouflage, that is the painting of vehicles in a similar colour to the background that they are operating against. This is often augmented by covering them with scrim, net and foliage. Whilst this visual camouflage is valid it offers little protection against weapons and weapon systems that operate on wavelengths other than those of the visible spectrum. More active measures of concealment such as smoke obscurants have the advantage of masking against some electro-optical devices but also suffer the disadvantage of revealing the users whereabouts.

Armoured vehicle weight has increased steadily over time and many observers would agree that this increase in weight, although helpful in absorbing the"blunt trauma"of a hit, adversely affects the vehicles mobility and the transportation of such vehicles to theatre. Additional and usually thicker armour is often the reason for increased vehicle weight but in an attempt to protect against, for instance, a larger calibre projectile the addition of thicker armour also defeats smaller calibre projectiles that the vehicle existing armour already protects against. This not only produces an unnecessary duplication in protection but also an unnecessary increase in weight.

An object of the invention is to provide units and modules for fitment to vehicles in order to enhance at least the stealth protection of the vehicle.

In one aspect the invention provides stealth protection/armour for military use comprising one or more units each composed of spaced apart rigid strip-like elements all connected together at one margin by a base to form a skeletal three-dimensional structure and adapted for fitment to a vehicle with a minimal dimension of the elements facing outwardly. The strip-like elements may be arranged as an array of parallel components.

In another aspect the invention provides stealth protection/armour for military use comprising one or more units each composed of strips of flexible material all suspended from or otherwise interconnected at one margin and adapted for fitment to a vehicle with a minimal dimension of the elements facing outwardly. The minimal dimension of the strips or strip-like elements may be side edges or ends of the strips.

Stealth protection/armour in accordance with the invention can have two distinctive functions.

Firstly affecting"soft kill"i. e., to prevent the vehicles from being targeted by reducing the electro-optical signature as camouflage reduces the visual signature and secondly"hard kill"i. e. , if targeted and hit reducing the probability of vehicle penetration primarily by means of projectile deflection. In the later functionality it is useful to have hollow box-section joining pieces between the elements making up the base. Each element can then be composed of a hollow casing in which a suitable packing is placed. Tensile bolts can extend between the elements.

The stealth protection/annour is a"last on board" appliqué, i. e. it is fitted above all other existing armours including explosive reactive armours (ERA's) and, as far as possible, all vehicle fittings and fitments should be enclosed within it.

The stealth protection/armour is passive continuously functions unpowered in three-dimensions (3-D) to reduce a vehicle's thermal cue by increasing the vehicle's apparent surface area, as in a heat sink, but at the same time reducing the visual impact by presenting a smaller surface area to the eye. Because of its three-dimensional (3-D) skeletal nature the armour is light relative to existing flat or two dimensional (2-D) armours and this also allows it to be used as a'chassis'onto which a sub-architecture can be fitted. This architecture might, for example, include radar absorbent material (RAM) and laser absorbent/reflective material, both used to increase stealthiness and carry these in such a manner so as to protect them from direct physical abrasion.

The units constituting the protection/annour may also carry hardware such as solar collectors for vehicle battery charging and electro-optical devices for surveillance, and carry such devices in a similar open shelter arrangement, with any associated wiring conduits within the box sections at the base of the unit.

Because of the materials and coating that may be applied as a part of the stealth package the units making up the armour may of necessity remain unpainted. Any colour component may be added by means of variously coloured sleeves of plastic, nylon or similar and fitted or removed from the elements leading outwardly facing edges by hand.

The primary function of the stealth protection/armour, as previously stated, is to reduce or prevent the vehicle fitted with it from being successfully illuminated by laser designators and to reduce the'pings'or returns of laser range finders and to reduce radar'spikes'as well as reducing the vehicles infra-red (I-R) cue to background levels. However it can also offer a high degree of protection from projectiles fired in line of sight engagements. Due to its skeletal nature, and because the armour is in effect'side on'to the threat, a shape inherent in a heat sink, the armour presents an extreme geometry relative to that of a flat two-dimensional (2-D) armour. This geometry should cause severe degradation to a projectiles performance by inducing yaw, causing shouldering and ricochet or shattering, Yaw can be overcome by increased projectile velocities but a correctly aligned armour with respect to a projectiles trajectory can impart sufficient yaw to that projectile as to overcome any velocities that current missiles or gun/propellant systems are capable of. The extent of projectile performance will also depend upon the materials used in the construction of the armour and its dimensions. The elements of the armour may be manufactured from any of the armours available and either case in metals or fabricated using laminates or composites.

Where the stealth protection is made of flexible strips it acts as a lamboy and in addition to the rigid structure described herein a lamboy may be used in areas where flexible armours only will suit. Lamboys are similar to rigid armours in their use insofar that they are three-dimensional and may be used to carry items of armour and stealthy material within their three-dimensional arrangement. Lamboys may be used under turret bustles and around turret race rings they are also ideal for masking track-laying vehicles running gear.

Embodiments of the invention will now be described by way of examples only with reference to the accompanying drawings and photographs in which: Figures 1,2 and 3 collectively illustrate the processing of strip-like elements usable in the invention; Figure 4 is a cross-sectional view of a unit constructed in accordance with the invention; Figure 5 is a cross-sectional view of the unit shown in Figure 4 with several optional additions; Figure 6 is a side view of the unit shown in Figure 4; Figures 7 and 8 are side views of alternative forms of the unit shown in Figures 4 and 6; Figure 9 is a cross-sectional view of another unit constructed in accordance with the invention; Figure 10 is a side view of the unit shown in Figure 9; Figures 11 to 19 are photographs showing models of a number of different units constructed in accordance with the invention; Figure 20 is a photograph showing an alternative flexible stealth unit constructed in accordance with the invention as fitted to a vehicle;

Figure 21 is a photograph showing an array of elements making up another unit constructed in accordance with the invention; Figure 22 is a photograph showing a number of spaced-apart units constructed in accordance with the invention fitted to a vehicle and Figure 23 is a photograph showing an array of different elements making up another unit constructed in accordance with the invention.

As appears hereinafter, the invention is primarily concerned with the construction and use of units to act as camouflage for a military vehicle and secondarily with such units which act also as armour or additional armour for protecting the vehicle.

Figure 1 shows a flat or two-dimensional plate made for example of aluminium. The plate would normally be machined by cutting the plate horizontally or vertically as in Figure 2 so producing a series of individual strip-like elements 14 with spaces between them and occupying a greater area as in Figure 3.

In Figure 3 the longitudinal dimensions of the elements 14 is perpendicular to the plane of the drawing so reference numeral 1 is the end of an element 14, references 2,3 are the edges and reference 20 the sides.

Figure 4 shows the series of elements 14 in cross-section and joined one to another at their lower ends by means of box sections 15 acting as joining pieces together forming a base 16 of a unit 17 constructed in accordance with the invention. Figure 6 shows the unit 17 in side elevation. The thickness of the elements 14 is exaggerated in Figure 4 and during use the unit 17 is fitted to a vehicle with the free edges 2 or the ends 1 of the element 14 facing outwardly and the base 16 adjacent the vehicle.

Figure 5 shows the unit 17 fitted with an (optional) sub-architecture the extent of which is variable but may include hard facings 18 and/or coloured sleeves 19 on the free edges 2 of the elements 14 and/or radar absorbent material (RAM) on the side surface 20 and/or laser absorbents/dispersants 21 in the spaces between the elements 14.

Figure 7 show the unit 17 with leading edges 2 of the elements 14 remote from the base 16 cut away to taper. In Figure 8 the edges 2 of the elements 14 are collectively given a curvilinear profile. Such measures increase stealth by reflecting radar, reduce weight and act in keeping the unit 17 clean.

Figures 9 and 10 show the end elevation of a heavier section unit 17. Whereas lighter elements 14 may break away under the weight of impact of a projectile causing that projectile to tilt or yaw, the elements 14 are here designed to cause ricochet or lateral interference. The elements 14 are composed of outer casings 23 of high hardness plate which is packed with material 22 which may not stand alone, i. e. glass, glass reinforced plastic (GRP), ceramics and the like.

Further rigidity may also be afforded by means of high tensile steel bolts 24 fitted at intervals transversely. These may also be seen in Figures 16 to 18.

Figure 11 shows several units 17 as in Figures 4,5 and 6 constructed in cast aluminium and serving as stealthy armour for fixing onto a vehicle hull or existing armour by means of chemically bonding or bolting. All units 17 but one are fitted with the coloured sleeves 19 and two lengths of fibre optic cable have been conduited through the box sections 15 for illustrative purposes. In this model it can be seen the units 17 can be built up into larger modules to cover a particular region of the vehicle.

Figure 12 shows units 17 with elements 14 with cut away leading edges 18 as in Figure 7 to reflect away radar and increase stealth. Some sleeves 19 (in UN white) are shown yet to be fitted.

The depth of the elements 14 are variable and may be determined by trial.

Figure 13 shows a module with a variety of units 17 in which some of the elements 14 are of different heights and the leading edges 2 are cut away and arranged so as to produce a fractoforrn.

Fractoforms are visually ambiguous and help to break up regular surfaces and although generally unsuitable for walking upon may be used to envelope fittings and fitments or, for example, break up the outline of turret mounted sights.

Figure 14 shows units 17 similar to that shown in Figure 13 except the leading edges 2 are cut away in alternate directions producing a more complicated fractoform to increase the visual ambiguity. None of the units 17 shown in Figures 13 and 14 are fitted with coloured sleeves 19

but such sleeves 19 can be used. For illustrative reasons the units 17 in Figures 13 and 14 are shown carrying hardware, in Figure 13 a battlefield microphone and in Figure 14 a camera. Such hardware is housed in an open shelter arrangement within the elements 14 and the associated wiring channelled through the box sections 15.

Figure 15 shows a section of a module composed of units 17 configured for use around a vehicle's track or wheel line. In this case the element 14 has a triangular or saw-tooth profile to the leading edge 2. This module can be fitted over the skirt plates of a main battle tank (MBT) or in heavier section on such a vehicle's bow and stern plates. The edge 2 profile helps prevent the elements 14 from being impacted with mud and earth, and the resulting shape also helps to reduce radar cross section (RCS). The leading edges 2 are fitted with hard facings 18 instead of coloured sleeves 19. The side surfaces of the outer elements 14 have been painted to illustrate the effects of self camouflage.

Figure 16 shows a unit 17 with ribbed or 3-D hard facings on the leading edges 2 of light alloy elements 14. The side surfaces of the elements are coated with radar absorbent material (RAM) to reduce a vehicle's radar cross section (RCS). The RAM should be particularly magnetic to the millimetre wave (mmW) and centimetre wave (cmW) 'pencil beam'or imaging radars used by anti-tank/attack helicopters. As with all the units 17 it may be walked upon and reasonably heavier equipment may be lain upon it without risk to abrasion sensitive coatings or other items.

All units 17 may be kept clean with water and/or compressed air jets of moderate pressure.

Figure 17 shows a unit 17 essentially as that shown in Figure 16 but of heavier section. In order to increase stealth, the hard facings on the edges 2 carry light gathering rods in addition to the light gatherers shown above the box sections 15. Whilst it is not possible to prevent a vehicle from being laser'splashed'the resulting'sparkle'may be reduced, without which no'basket'can develop for a laser designated weapon to fall into. Yellow light absorbers, or as depicted in Figure 9 angular deflectors 21, are shown as this colour may help negate the effects of the NdYAG a commonly used battlefield laser. As with all sub-architecture this can be altered to suit different threats and circumstances.

Figure 18 shows units based on the embodiment of Figures 9 and 10. In the model, the elements 14 are made up with casings 23 of depleted uranium (DU) and the material within the casings 23 is an armour of polycarbonate. The transverse bolts 24 are fitted to help prevent splaying of the elements 14 should a kinetic energy (KE) projectile drive between them. This places the bolts 24 at this point into tension but adjacent bolts 24 into compression helping to keep the elements parallel to each other and increasing the projectiles lateral interference and therefore its braking moment.

The spacing between the elements 14 is concerned with the weight to projection ratio. As a general rule the elements 14 should not be placed so far apart so that the sub-architecture comes into contact with abrasive forces. On the other hand there is no reason to place the elements 14 so close together so as to stop a projectile of a calibre size that the armour to which the unit 17 is attached is already capable of stopping. Closer spacing of elements 14 may be required for subcalibre round which are capable of penetrating vehicle hull armour, such rounds include the

Armour Piercing Fin Stabilized Discarding Sabots (APFSDS) in which case the elements 14 should be spaced so as to cause lateral interference to the long rod penetrator. The ballistic tolerance of any of the units 17 will depend on the materials used in their construction, the type of threat presented to them and other variables.

Figure 19 shows a unit 17 as in Figure 4 but constructed in stainless steel and perforated to allow free movement of air through it. This type of arrangement may be used for engine decks. The box sections 15 carry engine oil cooler/engine jacket water piping as shown.

All units 17 are essentially as depicted in Figure 4 but, as may be seen in Figures 20 to 23, the strip-elements 14 can be made flexible and lend themselves to various configurations within a three-dimensional outline. In this context the flexible theme can be extended to include lamboys.

Lamboys may be used in areas where only flexible armours will suit, such as around turret race rings under turret bustles and as extensions to skirt plates. Lamboys are similar to ridged armour in their use insofar that they are three-dimensional and may be used to carry armour and stealthy materials within their three-dimensional format.

Figure 21 shows a lamboy representing another unit constructed in accordance with the invention which uses an array of flexible strips. The strips making up the lamboy are suspended from a threaded bar and light chain or stainless steel cable traverses the strips at intervals in the drop in order that they may hang straight and in order. The strips may be made from a variety of materials including nylon webbing,"Kelvar" (RTM) or as shown alternate strips of infra-red (I-

R) absorbent materials and rubber. Because the strips hang from a threaded bar the spacing between them is variable.

Figure 20 shows a model of a Main Battle Tank (MBT) with lamboys extending from the lower edge of the skirt plate to the ground. In the photograph a section of lamboy is missing revealing one of the road wheel stations beneath. Tank running gear can generate significant amounts of infra-red (I-R) energy as well as an acoustic footprint and the road wheels are good radar reflectors. Lamboys can help reduce these signatures.

Figure 22 shows the side view of a gun tank with lamboys only partially fitted. Because these lamboys are permanently coloured they would need to be produced in a variety of colours to suit different backgrounds for this reason and because being around the track line they are subject to damage they would need to be easily removed and replaced by tank crew members.

Figure 23 shows single material lamboy with strips of e. g."Kelvar"tightly hung together. This lamboy when'side on to threat'will offer'disturber'or stand off protection whilst allowing lateral movement. Hung in depth as in this photograph, i. e. one set upon another and/or the strips formed into pockets with solid armour blocks fitted within such pockets would offer a stealthier alternative to hanging chain, sometimes fitted under turret bustles and other turret sponsons.

Claims

Claims 1. Stealth protection/armour for military use comprising one or more units each composed of spaced apart rigid strip-like elements all connected together at one margin by a base to form a skeletal three-dimensional structure and adapted for fitment to a vehicle with a minimal dimension of the elements facing outwardly.
2. Stealth protection/armour for military use comprising one or more units each composed of strips of flexible material all suspended from or otherwise interconnected at one margin and adapted for fitment to a vehicle with a minimal dimension of the elements facing outwardly.
3. Stealth protection/armour according to claim 1, wherein the strip-like elements are connected with the aid of hollow-section joining pieces extending therebetween to form the base.
4. Stealth protection/armour according to claim 3, wherein the elements are each composed of a casing enclosing a packing material.
5. Stealth protection/armour according to claim 4, wherein bolts extend transversely of the or each unit to interconnect the elements at locations spaced from the base.
6. Stealth protection/armour according to claim 3,4 or 5, wherein edges of at least some of the elements which face outwardly have hardened facings or coloured sleeves thereon.

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7. Stealth protection/armour according to any one or more of claims 1, 3, 4,5 or 6, wherein material which absorbs or disperses laser beams is contained in the spaces between at least some of the elements.
8. Stealth protection/armour according to any one or more of claims 1, 3,4, 5,6 or 7, wherein the side surfaces of at least some of the elements are coated with radar absorbent material.
9. Stealth protection/armour according to claim 1 or any one or more of claims 3 to 8, wherein the edges of the elements remote from the base and facing outwardly in use are tapered in relation to the base.
10. Stealth protection/armour according to claim 1 or any one or more of claims 3 to 8, wherein the edges of the elements remote from the base and facing outwardly in use are shaped to define a curvilinear profile with respect to the base.
11. Stealth protection/armour according to claim 9 and composed of a number of said units at least some of which have elements with tapered edges, the units being arranged to form a module or block of fractofonn configuration.
12. Stealth protection/armour according to claim 1 or any one or claims 3 to 8, wherein the edges of the elements remote from the base and facing outwardly in use are of triangulated form.

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13. Stealth protection/armour according to claim I or any one of claims 3 to 12, wherein the sides of the elements are perforated.
14. Stealth protection/armour according to claim 2, wherein cable or chains extend through the strips.
15. Stealth protection/armour substantially as described with reference to, and as illustrated in, any one or more of the Figures of the accompanying drawings.
16. A vehicle when fitted with stealth protection/armour according to any one or more of the preceding claims.
17. A method of enhancing at least the stealth protection of a vehicle; said method comprising attaching one or more units to the vehicle, each unit having the features of any one or ore of the preceding claims.