GB2251923A - Water-to-air missiles - Google Patents

Description

A METHOD OF ATTACKING TARGET OBJECTS BY GLEANS OF A PROJECTILE Wl!ICII CAN BE ACCELERATED IN TIlE WATER, t4D A DEVICE FOR CARRYING OUT THE L'IETIQOD The invention relates to a method in accordance with the definition of the species of claim 1 and to a device in accordance with the definition of the species of claim 4.

To attack displacement vessels as target objects, it is known to use torpedoes as projectiles which, by means of self-drive and remotecontrolled, or self-steering by way of a location facilitity, bring a service charge up to the target and detonate it in the vicinity thereof or after impact.

What is disadvantageous in the case of this method is the only limited speed which can be achieved by means of the self-drive and which is not adequate for pursuing and attacking target objects which are moving away rapidly. Furthermore disadvantageous is the large volume of the projectile, which has to take along with it both a large-volume drive with energy supply, and a voluminous service charge, in order even in the event of the detonation thereof in the case of mere target object proximity to develop, by way of the water pressure wave, a sufficient effect, namely if possible to render the target object incapable of action. In this respect, the effect against target objects which do not represent conventional displacement watercraft - such as, for instance, air-cushion or airfoil boats - is, despite the large warhead, slight.

The wide-swung approach run path of torpedoes is, moreover, relatively easy to detect from the target object; so that, over and above mere run-off acceleration, the target object is left with further defensive or evasive possibilities such as the launching of deception bodies or defensive explosive charges and evasive manoeuvres with good prospects of success.

This holds true to a particular extent also for the proposal to use, instead of torpedoes that are to be fired in an aimed manner, target-seeking mines which as buoyancy bodies describe an oblique ascent path from a waiting position by means of airfoils.

The attacking of target objects by means of projectiles fired as rockets from a ship or from a submerged anchorage position is also known. In this case, too, more especially logistically and with respect to depot safety, the weight and the large space requirement, occasioned by the drive unit together with its propellant and the large warhead, is disadvantageous.

The problem underlying the invention is, therfore, to indicate a method or respectively a device of the kind in accordance with the species which lead to successful attacking of target objects with considerably less space and weight requirement for the drive of the projectile and for its service charge with simultaneously increased certainty of a hit and effect of a hit even when it is a matter of non-conventional vehicles on or above the surface of the water (such as air-cushion vehicles or low-flying helicopters) which can be attacked with the discussed conventional means only limitedly or respectively with small effective radius. In this respect, the device is to be difficult to discover and to clear, but to have a large radius of action.

This problem is solved in accordance with the invention essentially in the case of a method of the kind quoted at the beginning hereof in that it additionally has the partial features of the characterising part of claim 1, and in the case of a device of the kind quoted at the beginning hereof in that it is additionally developed in accordance with the partial features of the characterising part of claim 4.

The invention is based, in this respect, on the recognition that it ought to be possible to use a projectile which, on the one hand, can be set out like a ground mine and be activated by the approaching target object; but which, on the other hand, carries out the direct attack on the target object not from the water but like a missile. By hugging the sea bed it is ensured that it is not only difficult to locate, but also cannot readily be put out of action by current drag means, although it has considerable cylindrical dimensions.Moreover, the projectile lying on the sea bed has, in the direction of the surface of the water, a comparatively large surface area, on which various active and/or passive locating devices can be installed; in which respect, also by reason of the relatively large surface area which is available, groupings for specific locating characteristics in the interests of great acquisition ranges are realisable.

If one of these locating devices picks up the energy radiation of a target object, the projectile is stood upright by the deliberate effect of buoyancy forces. Then it is, for example, accelerated in a projectile-like manner, for which the explosively-rapid deflagration of a propellant charge, which is small but which develops a great deal of combustion gas, behind the tail of the projectile is sufficient.

The projectile which has been accelerated in a directionally-stable manner by this - or, instead of this, by means of a hydrostatic buoyancy chamber in the tip of the uprighted projectile - and then, if necessary, further propelled by means of an additional small sustainer, shoots through the surface of the water relatively far up into the air space where, after traversing a ballistic trajectory, it is then arrested by means of a deployed parachute. The target object, which has been acquired by a projectile locating device and thereby led to the erection and acceleration of the projectile on the sea bed, is thus, in the interests of a large effective radius with low locating expenditure, still not at all to be hit in direct fire upon the projectile-like surfacing of the projectile.On the contrary, after that first the projectile then sinking down circling on the parachute searches for the target object - as is known as such in the case of target-seeking sensor artillery ammunition - for example spirally by means of a search head along the periphery of an area, initially very large and then becoming smaller with the descent path, above the surface of the water. Upon target acquisition in the longitudinal direction and thus in the effective direction of the projectile, the sustainer thereof is started up anew, or projectileforming service charges are discharged. In this way there results, on account of the great probability of a hit, the requirement of only relatively small warheads (in the order of magnitude of 0.1% up to 1% of the above-discussed conventional service charge weights).For a propellant charge for the projectile-like lift-off from the sea bed, it even needs only a propellant charge weight in the order of magnitude of 2% of the total weight of the projectile. Thus, small and easy-to-handle projectiles, difficult to detect on the sea bed, can be used for a very highly effective attacking of even rapidly moving target objects in a large effective radius on and above the surface of the water.

Suitable for the propellant charge for projectile-like lift-off from the sea bed are pyrotechnical materials which combust very rapidly and in so doing - possibly by reason of appropriate material additives - generate the greatest possible amount of combustion gases.

To be striven for are explosively-rapid deflagration or detonation velocities namely similar to 100 m/s and, if possible, up to 2,000 m/s. With current pyrotechnical materials such as, for example, on the basis of potassium perchlorate or with specifically deflagrating or detonating propellant charge powders, for example on the basis of nitrocellulose or nitroglycerine, as propellant charge or respectively by means of explosive with a low detonation velocity, there result initial accelerations of the projectile which - if necessary - can by all means almost reach the acceleration of a conventional projectile upon launching in a weapon barrel, although no kind of conventional launching device, to be installed fixedly at the launching site, is necessary.

Additional alternatives and further developments as well as further features and advantages of the invention will become apparant from the sub-claims and from the following description of a functional diagram, shown in the drawing along with a restriction to that which is essential in a highly simplified manner and not to scale, for the use of a device in accordance with the invention for carrying out the method in accordance with the invention.

To attack target objects 1 on or above the surface of the water (such as for instance low-flying helicopters or surface watercraaft), a service charge 3 is disposed in an elongatedly-cylindrical projectile 4. In this respect, it can basically be a matter of a conventional article of ammunition such as antitank projectile which is sheathed in a flow-favourable manner by a wall 7. The projectile 4, which is launched into the water 5, is dimensioned as a sinking body and in such a way that it sinks down in a preferential orientation onto the sea bed.The preferential orientation, in other words the position on the sea bed 6, can be ensured more especially by appropriate weight distribution in the cylindrical body of the projectile 4; namely in such a way that an (active or passive) locating device 8 installed along the wall 7 is orientated substantially at the surface 2 of the water.

The lengthwise extent of the locating device 8 consisting of a group of transducers parallel to the longitudinal axis 9 yields, for a spatially specifically limited location region, a locating characteristic 10 which is severaly bunched in the direction of the longitudinal axis 9 of the projectile and is less severely bunched transversely thereto.

With a view to the large effective radius of the projectile 4, instead thereof, or additionally, a number of obliquely orientated receivers 11 can be provided, which already at great range detect the approach of a target object 1. Finally, for the detection of the target approach, a thin rod antenna 30 for a rotationally-symmetrical radar lobe can also be provided, which is held by a small buoyancy body 31 moored to the projectile 4.

Since the projectile 4, lying flat, hugs the sea bed 6, it is, despite considerable cylinder dimensions, in other words despite fundamentally easily locatable geometry, difficult to discover with water-borne sound locating measures for targeted mine combatting measures; all the more so since the projectile 4, depending on the factors of its geometry and the undercurrent, is also additionally after a certain time more or less covered in sand.

If, by means of the locating device 8, at the surface 2 of the water for example the sounds of the approach of a target object 1 are discerned, then a righting device 12 is started up, by means of which the head end 13 of the projectile 4 experiences a greater buoyancy than its tail 14. For this, for example the inflation of a previously folded-together buoyancy balloon from a store of compressed gas or the blowing of one of the tanks flooded for the sinking of the projectile 4 onto the sea bed 6 can be provided for. In the case of the exemplified embodiment shown in the drawing, provision is made for the fact that by means of a supply of compressed gas at the head end 13 a ballistic cap 15 is pushed forward, whereby a cavity - possibly even filled with the propulsion gas - is provided as buoyancy chamber 16.

After the projectile 4 has been stood upright, namely is orientated at least approximately perpendicularly in the water 5, it lifts off from the bottom 6. For this, the buoyancy effect of the chamber 16 can suffice. It can be more advantageous, more especially in the case of fast target objects 1, to provide for the fact that, by an incorporated time and/or inclination indicator 17, a propellant charge 18 is detonated, which is arranged in a propellant-charge container 19 behind the projectile tail 14 and deflagrates very rapidly along with powerful development of combustion gas.In this way the container 19 is torn open rearwardly, and the combustion gas passing over suddenly into the surrounding water 5 forms, behind the container 19 in the surrounding water 5 - which reacts in an incompressible manner to this temporal stressing - as a result of the strong supply of combustion gas, a rapidly expanding combustion-gas bubble 20. This expansion of the bubble 20 gives rise to forces of reaction in the water 5 (and initially also on the sea bed 6) which accelerates the uprighted projectile 4 in a projectile-like manner, for example with an initial acceleration which comes close to that upon the launching of a conventional projectile from the barrel of a weapon, in the direction of the surface 2 of the water.The incident flow 21, occurring in this respect, at the container wall 22 parallel to the longitudinal axis 9 leads to a hydrodynamic damming of the container 19, which thus, as a result of the reaction pressure by reason of the explosively-rapid combusting propellant charge 18, displays itself only slightly, into a fruso-conical cross-sectional shape, and thus acts as a sabot for the acceleration pressure effect by way of the combustion-gas bubble 20. Provision can, however, also be made to design the container 19 as a pressure-resistant sabot 23, in order to ensure its inherent stability even in the case of disturbances of the incident flow 21 during the lift-off from the sea bed 6.

The exceptionally high acceleration of the projectile 4 upon lift-off from the sea bed 6 brings about the formation of a closed cavitation envelope 24 around the ballistic cap 15 and the rest of the body of the projectile, which rapidly coalesces with the rearward further-expanding combustion-gas bubble 20. In this way, the projectile 4 then moves without physical contact with regard to the surrounding water 5, in other words in a spatially-stable manner in the original firing direction at high speed towards the surface 2 of the water. After origination of this initial acceleration, a sustainer (not taken into account in the drawing) can also be ignited, in order to undertake the further propulsion.

At all events the projectile 4 emerges from the surface 2 of the water and traverses a relatively high ballistic trajectory. An incorporated apogee detector 25 releases, shortly after flying through the zenith of this path curve 26, a parachute 27 which is accommodated, for example, at the tail 14 and on which the projectile 4, suspended for example eccentrically, falls in a relatively severly decelerated manner back again in the direction of the surface 2 of the water. With eccentric suspension and corresponding eccentric development of the supporting behaviour of the parachute 27, the projectile 4 carries out in this respect a rotary motion abouts its direction of fall 28. A target detector 29, for example a metal detector or an infra-red detector, incorporated into the projectile 4 searches in this respect the air space between projectile 4 and surface 2 of the water in a manner known as such (for example spirally) for a target object 1 - as a rule in other words for the one which has been acquired by the locating device 8. Upon target acquisition in the direction of the longitudinal axis 9, the sustainer arranged in the tail 14 can be ignited afresh, so that the projectile 4, along with separation from the parachute 27, attacks the target object 1. Provision can, however, also be made to fire at once the service charge 3 as a projectile-forming charge from the projectile 4.

Claims (11)

1. A method of attacking target objects by means of a projectile which is drivable in the water and which is equipped with a locating device for the acquisition of a target object, characterised in that the projectile is deposited on the sea bed and, upon acquisition of a target object on or above the surface of the water, is stood upright and is accelerated in the direction of the surface of the water, in that the projectile, after emerging from the water, is arrested aerodynamically, and in that the projectile, after detecting a target object on or above the surface of the water, attacks this.

2. A method as claimed in claim 1, characterised in that, upon detection of a target object by means of the locating device, a buoyancy cavity is formed in the region of the head end of the projectile and is, in appropriate circumstances, filled with buoyancy gas.

3. A method as claimed in claim 1 or 2, characterised in that, after righting of the projectile, a propellant charge arranged behind its tail is ignited, which, along with explosively-rapid combustion, rich in combustion gas, behind the projectile forms and expands a combustion-gas bubble, the forces of reaction of which at the surrounding medium which is incompressible with respect to this accelerate the projectile in a projectile-like manner in the direction of the surface of the water.

4. A device for attacking a target object (1) by means of a projectile (4) which is equipped with a drive device for the propulsion through water (5) and with a target-object locating device (8), more especially for carrying out the method as claimed in at least one of claims 1 to 3, characterised in that the projectile (4) is equipped with a buoyancy device in the region of its head end (13) as well as with an arresting device working outside the water (5) and a target detector (29).

5. A device as claimed in claim 4, characterised in that the projectile (4) has, in front of its head end (13), a ballistic cap (15) which can be pushed forward and which can be filled with buoyancy gas.

6. A device as claimed in claim 4 or 5, characterised in that a propellant-charge container (29) acting as a sabot (23) is arranged behind the tail (14) of the projectile.

7. A device as claimed in one of claims 4 to 6, characterised in that the locating device (8) is connected to a rod-shaped radar antenna (30) which can be held by a buoyancy body (31), moored to the projectile (4), at the surface (2) of the water.

8. A device as claimed in one of claims 4 to 6, characterised in that the locating device (8) is equipped with long-range water-borne sound receivers (11).

9. A device as claimed in one of claims 4 to 7, characterised in that the projectile (4) is equipped with at least one sustainer for the ascent out of the water (5) and/or for the the attack on the target object (1).

Amendments to the claims have been filed as follows 1. A method of attacking target objects by means of a projectile which is drivable in the water and which is equipped with means for detecting and locating a target object, characterised in that the projectile is deposited on the sea bed and, upon detection of a target object on or above the surface of the water, is stood upright and is accelerated in the direction of the surface of the water, in that the projectile, after emerging from and rising above the water, has its descent retarded aerodynamically and searches for a target, and in that the projectile, after locating a target object on or above the surface of the water, attacks this.

2. A method as claimed in claim 1, characterised in that, upon detection of a target object a head end of the projectile is made buoyant.

3. A method as claimed in claim 1 or 2, characterised in that, after righting of the projectile, a propellant charge, arranged at the tail of the projectile, is ignited, to combust in an explosively-rapid manner to form and expand a combustion-gas bubble producing forces of reaction sufficient to accelerate the projectile in a projectile-like manner in the direction of the surface of the water.

4. A method of attacking target objects substantially as hereinbefore described with reference to the accompanying drawings.

5. A projectile constructed to be laid on a sea-bed and comprising a target object detecting device for detecting a target object on or above the surface of the water under which the projectile reposes; a buoyancy device actuable by the detecting device to provide buoyancy for a head end of the projectile for righting the projectile; a drive device to drive the projectile upwards to and through the surface of the water; an aerodynamic arresting device to retard the descent of the projectile towards said surface; a target detector to locate a target from above said surface;: and means s to cause the projectile to attack a located target.

6. A projectile as claimed in claim 5, characterised in that the buoyancy device comprises a ballistic cap at a head end of the projectile, which cap can be pushed forward and which can be filled with buoyancy gas.

7. A projectile as claimed in claim 5 or 6, characterised in that the drive device comprises a propellant-charge container, which acts in a sabot-like manner, arranged at the tail of the projectile.

8. A - projectile as claimed in any one of claims 5 to 7,

characterised in that the

device isconnected'to a rod-shaped radar antenna which can be held by a buoyancy body, moored to the projectile, at the surface of the water.

9. A Projectile as claimed in anv one of - claims 5 to 8,

characterised in that the

device isequipped-with long-range water-borne sound receivers.

10. A projectile as claimed in any one 'of claims 5 to 8, characterised in that the projectile is equipped with at least one sustainer for the ascent out of the water and/or for the the attack on the target object.

11. A projectile substantially as hereinbefore described with reference to the accompanying drawing.