GB2406895A - Ejecting cargoes from missiles - Google Patents

Abstract

A missile has an air breathing ram jet engine, an ejectable cargo 20 (e.g. torpedo) carried by the missile and means for ejecting the cargo 20. The ejector means comprises a pressurisable chamber 28 defined by a wall of the cargo, a wall 19 of the missile and a flexible seal 26. A conduit 29 interconnects the chamber to an engine air intake at a region where, in flight, the static air pressure in the intake exceeds the ambient air pressure on the missile. A valve 30, operable to open the conduit 29 when it is desired to eject the cargo from the missile, admits pressurised air to the chamber 28 and displaces the cargo relative to the missile: simultaneously explosive bolts are fired to release the cargo. The remainder of the missile is decelerated on ejection of the cargo by means of air brakes 31 and/or by shutting down the engine. The valve 30 may supply air to a series of chambers 28 in turn for ejecting a series of cargoes.

Description

MISSILES WITH EJECTABLE CARGOES

This invention relates to missiles and, in particular, to missiles capable of carrying and ejecting a payload or cargo. The term cargo as used herein includes torpedos, surveilance devices, explosive devices, marker buoys, or similar devices.

Ejectable cargo such as torpedos, surveilance devices, or explosive devices are often fitted with sensors that seek out a target when dropped into the sea. There is a need to be able to eject such cargoes without causing the remainder of the missile to fall within the range of the sensors of the cargo and disrupt the intended mode of operation of the ejected cargo.

An object of the present invention is to provide a missile with a means of ejecting a cargo whilst allowing the remainder of the missile to fall out of range of the ejected cargo.

According to the present invention there is provided a missile having an air breathing engine and an ejectable cargo carried by the missile, the missile being provided with a cargo ejector means comprising a pressurizable chamber defined by a wall of the cargo and a wall of the missile, a conduit means interconnecting the chamber to an engine air intake at a region where, In flight, the static air pressure in the intake exceeds the ambient air pressure on the missile, valve means operable open the conduit when it is desired to initiate ejection of the cargo from the missile thereby to admit pressurized air to the chamber and displace the cargo relative to the missile and deceleration means for deceler- ating the missile relative to the ejected cargo.

Preferably the cargo constitutes a front portion of the missile and the chamber is defined by a rear wall of the cargo and a front facing wall of a rear portion of the missile.

Preferably the rear portion of the missile defines a forward facing cavity closed, at its rear end, into which the cargo is located,and the pressurizable chamber is defined by a rear wall of the cargo and the closed rear end of the cavity.

Preferably the cargo is provided with a flexible sealing member that cooperates with the side wall of the cavity to define a fluid tight seal for the pressurizable chamber.

Releasable means may be provided for holding the cargo in the cavity, and tensioning means may be provided for securing a detachable nose cone to the front of the cargo.

The deceleration means may comprise air brakes or means for shutting down the engine.

The invention will now be described,by way of an example,with reference to the accompanying drawings in which: ' Figure 1 illustrates schematically a missile constructed according to the present invention embodying means for carrying and ejecting a torpedo.

Figure 2 illustrates in greater detail the ejector mechanism of the missile of Fig. 1.

Referring to the drawings, there is shown a combined rocket ramjet propelled missile lO,which is provided with three wings 11 at a midsection for providing lift and three canard wings 12 at its front for controlling attitude of the missile during flight.

The propulsion unit is an air breathing ramjet engine 13 having an air intake 14 and a liquid or solid fueled booster rocket 15.

The rear portion 16 of the missile is provided at its front with a forward facing cylindrical cavity 17 surrounded by liquid fuel tanks 18. The cavity 17 is open at its front end and closed at its rear end by a rear wall 19. Located within the cavity 17 is a torpedo 20 (or other ejectable cargo). The torpedo is held in place in the cylindrical cavity by means of a nose cone 22 which is bolted to the front face of the rear portion of the missile by means of explosive bolts 23. The nose cone 22 is itself bolted by means of explosive bolts 21 to the front of the torpedo 20.

A tail driving ring in the form of an annular member is secured around the rear end of the torpedo 20 by means of tensioning cables 26 which are attached to the nose cone 22. The tail driving ring 25 is provided with a flexible rubber sealing member 26 which co-operates with the wall of the cylindrical cavity 17 to define a pressurizable chamber 28 defined by a rear wall of the torpedo 20 and the side walls and rear walls of the cylindrical cavity 17. A conduit 2'3 interconnects the pressurizable chamber 28 to a point within the air intake 14 where the static pressure in the air intake exceeds the air pressure exerted on the nose cone of the missile during flight at speeds in excess of Mach II. A valve means 30 is provided in the conduit 29 to control the flow of air to the pressurizable chamber 28.

The region where the pressure is tapped in the air intake is typically of the order of 75 pounds per square inch during flight of the missile, compared with a pressure exerted on the nose cone at a speed of Mach II of 44 psi.

This gives a differential pressure ratio of 2.27 or a differential pressure of 31 psi. Therefore, for a missile of a diameter of the order of 12 inches the pressure tapped from the air intake would exert a forward force on the rear of the missile of the order of 3,900 pounds when the valve 30 is opened.

The missile is launched in the air by firing the expendable rocket motor 15 and after ejection of the booster rocket motor 15 the missile is propelled by the liquid fueled rarnjet engine 13.

The sequence involved in ejecting the torpedo is as follows: When the missile has attained a predetermined range over sea, the valve 30 is opened and the pressurized air admitted to the chamber whilst simultaneously firing the bolts 23 to release the torpedo 20, and shutting down the engine 13 by closing a valve 32 in the fuel supply line 33 to the engine. The pressure in the chamber 28 pushes the the torpedo 20 forward, and together with the momentum of the torpedo, accelerates the torpedo away from the rear portion of the missile. Air brakes 31 on the side of the missile are deployed to slow down further the rear portion of the missile (or at least prevent it increasing its speed) so that it falls into the sea a few kilometres before the torpedo falls into the sea.

The torpedo is provided with a parachute (not shown) for slowing its descent to a few knots relative to the sea when it is out of range of the remainder of the missile, and a control means is provided for detonating the bolts 24 that secure the nose cone 22 to the front of the torpedo 20.

Detonation of these bolts 22 also releases the tail driving ring 26 prior to the torpedo landing in the sea.

It is envisaged that a missile incorporating the present invention could be used for seeding an area of sea with a number of surveilance devices, torpedos, or explosive devices, or for seeding an area of land with explosive devices or other weapons. In this case, accepting that ejection of one cargo is liable to render the missile unstable in flight, it is not envisaged that the missile would continue any prolonged sortie after initiation of ejection of the first of a number of cargoes. Nevertheless, it is envisaged that by successively pressuring chambers behind individual cargoes by bleeding air pressure from the engine air intake and momentarily decelerating the remainder of the missile, it may be possible to eject a number of cargoes in quick succession before the missile finally crashes out of control. If the ramjet engine 13 is allowed to continue to burn then air brakes on the missile must be deployed to effect ejection of each cargo; upon retraction of the air brakes the lighter remainder of the missile would tend to accelerate for a given thrust of the ramjet engine 13 and in all probability the flight path would be unstable. On the other hand it may be necessary to shut down the engine on initiation of the ejection of the first cargo and rely on successive deployment and retraction of air brakes on the missile to effect ejection of successive cargoes.

In one arrangement the missile is provided with a plurality of cargoes located one behind the other and the valve 30 when opened supplies the pressurized air to a chamber behind each cargo. The pressurised air supply line to each chamber has a valve to control its pressuris- ation and these valves are operated in sequence so that only the foremost chanter is pressurized first and when the foremost cargo is ejected the next foremost chamber is pressurized and so on. The deployment of the air brakes is sequenced to decelerate the missile as each cargo is ejected and retracted immediately after separation is achieved.

Claims (10)

1. A missile having an air breathing engine and an ejectable cargo carried by the missile, the missile being provided with a cargo ejector means comprising a pressur- isable chamber defined by a wall of the cargo and a wall of the missile, a conduit means interconnecting the chamber to an engine air intake at a region where, in flight, the static air pressure in the intake exceeds the ambient air pressure on the missile, a valve means operable to open the conduit when it is desired to initiate ejection of the cargo from the missile thereby to admit pressurized air to the chamber and displace the cargo relative to the missile and deceleration means for decelerating the missile relative to the ejected cargo.

2. A missile according to Claim 1 wherein the cargo constitutes a front portion of the missile and the chamber is defined by a rear wall of the cargo and a front facing wall of a rear portion of the missile.

3. A missile according to Claim 1 wherein the rear portion of the missile defines a forward facing cavity closed at its rear end into which the cargo is located and the pressurizable chamber is defined by a rear wall of the cargo ancI the closed rear end of the cavity.

4. A missile according to Claim 3 wherein the cargo is provided with a flexible sealing member that co-operates with a side wall of the cavity to define a fluid tight seal for the pressurizable chamber.

5. A missile according to Claim 3 wherein releasable means are provided for holding the cargo in the cavity.

6. A missile according to Claim 5 wherein the tensioning means secures a detachable nose cone to the front of the cargo.

7. A missile according to any one of the preceding claims wherein the missile is provided with a number of ejectable cargoes and means are provided for decelerating the missile on the ejection of each cargo.

8. A missile according to any one of Claims 1 to 6 wherein the deceleration means comprises means for shutting down the propulsive engine of the missile.

9. A missile according to any one of Claims 1 to 8 wherein the deceleration means comprises air brakes on the missile.

10. A missile substantially as hereindescribed with reference to the accompanying drawings.