GB1605269A - Apparatus for the control of devices launched through the air into water - Google Patents

Description

(54) APPARATUS FOR THE CONTROL OF DEVICES LAUNCHED THROUGH THE AIR INTO WATER (71) I, SECRETARY OF STATE FOR DEFENCE LONDON, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for the control in water of a device launched through the air into the water.

In one aspect the invention relates to the control of an air launched torpedo during the period of its descent through the air and passage through the water prior to the commencement of its targeting run through the water under the control of sensing devices carried in the torpedo.

The physical characteristics of a torpedo are such that it may be inherently unstable so that when released from an aircraft it will fall in an unstable manner to the water. This would damage the torpedo and so make the subsequent functioning of the torpedo extremely difficult if not impossible. It is for this reason that in a known method of delivering a torpedo from the air to the water a parachute is attached to the tail region of the torpedo. After release of the torpedo from an aircraft the parachute is automatically deployed and both stabilizes and ccontrols the rate of descent of the torpedo through the air so that it hits the water in a controlled fashion at a speed typically of about 65 knots.Upon hitting the water the parachute is automatically disconnected to avoid excessive loads on the tail structure of the torpedo which would occcur if the parachute remained attached and was drawn through the water.

Disadvantages of this known method are that from the time of entry into the water and until the sensing devices on the torpedo become effective, the latter only being energised on entry into the water, the torpedo is uncontrolled; also, in view of the entry speed of the torpedo into the water, it may dive to a considerable depth which limits the shallow water capability of the torpedo.

Attempts to prevent the torpedo diving to too great a depth, for example by presetting upelevator, have not proved successful as the orientation in roll of the torpedo on entry is not controlled and therefore control forces from the preset elevator in the wrong sense can result. Furthermore, following entry of the torpedo into the water, there is a region to the rear and adjacent the tail of the torpedo which comprises largely air or a foam of air bubbles and water so that the control effect of elevators is in any case severely limited and further rolling may also be induced due to asymmetry of the cavity.

It is an object of the present invention to provide an improved method and apparatus for the control in water of devices launched through the air.

Apparatus for the control in air and water of a device launched through the air to the water according to the present invention comprises drag means, shock absorbing means and automatic disconnect means, the shock absorbing means and the disconnect means connecting the drag means to the device, wherein during the drag means retard and stabilize passage of the device through the air, after entry of the device into water the drag means react with the water to decelerate and stabilize the device and the shock absorbing means yield so that excessive loads on the device and the drag means are avoided, and subsequently the disconnect means releases the drag means from the device.

In the case of a torpedo launched from the air into the water the drag means may comprise a parachute which stabilizes and controls the rate of descent of the torpedo through the air and which fills at least partially with water after entry of the torpedo into the water to stabilize the motion of the torpedo in the water and to reduce its speed through the water.

The shock absorbing means may comprise a length of fabric material of uncut velvet construction as disclosed in British Patent No 1166245 and having two opposing face layers which are joined to each other by interconnecting pile members, wherein the one face layer is secured to the drag means and the other is secured to the tail structure of the device. After entry of the device into the water, the drag means reacts with the water and the interconnecting pile members tear progressively and absorb applied loads.

One embodiment according to the invention will now be described by way of example with reference to the accompanying diagrammatic drawings which show in side elevations four stages A, B, C and D in the controlled trajectory of a torpedo dropped from an aircraft into the water.

A torpedo 11, designed to be launched from an aircraft into the water 12, has a parachute 13 which is connected to the tail region 14 of the torpedo 11 by a shock absorbing device 15 and automatic disconnect means 16. The shock absorbing device comprises a length of undrawn polyester fibre fabric material of uncut velvet construction having two opposing face layers which are joined to each other by iterconnecting pile members of the kind as disclosed in British Patent No 1166245. At their one ends the face layers are secured the one to the rigging lines of the parachute and the other to the tail structure of the torpedo through the automatic disconnect means 16.

In use the torpedo 11 is carried by an aircraft with the parachute stowed in a pack at the tail of the torpedo. After release from the aircraft the parachute is deployed automatically and both stabilizes and controls the rate of descent of the torpedo through the air. By this means the torpedo enters the water in a stable fashion and at a speed of typically 65 knots. As the torpedo dives into the water a cavity 17 is formed around the torpedo which collapses towards the parachute as a mixture of water and air and the parachute fills at leat partially with water as shown at B and as a result of the increased drag, as water replaces air from the parachute, increased retarding forces are applied to the torpedo.As a result of the forces developed the interconnecting pile members tear progressively and absorb energy thus preventing the level of retarding load applied to the torpedo from increasing to the point where it would damage the tail of the torpedo and/or the parachute. After entry of the torpedo into the water and stabilisation to a required attitude as at C, the automatic disconnect means 16 operate to disconnect the torpedo from the shock absorbing device and may be made to operate in accordance with various functions such as time, depth or from signals from sensing devices carried on the torpedo.

Thus, in one example, a time sensitive device on the torpedo is triggered upon entry of the torpedo into the water and is operative after a predetermined time to set the torpedo drive motor in motion and the resulting rotation of the torpedo drive shaft acts simply to unscrew itself from the shock absorbing means.

Using this apparatus it is found that in the case of a particular torpedo the depth of penetration of the torpedo into the water varied from 20 to 26 feet with repeatable accuracy thus providing a shallow water capability. Furthermore, the torpedo was always in a controlled stable condition in the water as at C which is advantageous for enabling the sensing devices on the torpedo to take over to control the torpedo on its further run as at D.

In general the use of drogues or drag plates as drag means is not effective where the speed of entry of a device into the water is sufficient to cause a cavity region of air or a foam of air bubbles and water to exist behind and adjacent the tail of the device as at B. However, in cases where the speed of entry may be relatively low as in the case of a torpedo fired from a ship torpedo tube the use of such drag devices in place of the parachute may be possible.

The invention may also be used for the control of devices other than torpedos.

WHAT I CLAIM IS: 1. Apparatus for the control in air and water of a device launched through the air to the water comprising drag means, shock absorbing means and automatic disconnect means, the shock absorbing means and the disconnect means connecting the drag means to the device, wherein, the drag means retard and stabilize it, during passage of the device through the air after entry of the device into water the drag means react with the water to decelerate and stabilize the device in the water and the shock absorbing means yield so that excessive loads on the device and the drag means are avoided, and subsequently the disconnect means releases the drag means from the device.

2. Apparatus according to claim 1, wherein the automatic disconnect means are controlled by a time sensitive device triggered upon impact of the device with the water.

3. Apparatus according to claim 1, or claim 2 and wherein the drag means comprises a parachute.

4. Apparatus according to claim 1, 2 or claim 3 and wherein the shock absorbing means comprises a fabric material as disclosed in British Patent No 1166245.

5. Apparatus for the control in air and water of a device launched through the air to the water substantially as described herein with reference to and as illustrated by the accompanying diagrammatic drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. length of fabric material of uncut velvet construction as disclosed in British Patent No 1166245 and having two opposing face layers which are joined to each other by interconnecting pile members, wherein the one face layer is secured to the drag means and the other is secured to the tail structure of the device. After entry of the device into the water, the drag means reacts with the water and the interconnecting pile members tear progressively and absorb applied loads. One embodiment according to the invention will now be described by way of example with reference to the accompanying diagrammatic drawings which show in side elevations four stages A, B, C and D in the controlled trajectory of a torpedo dropped from an aircraft into the water. A torpedo 11, designed to be launched from an aircraft into the water 12, has a parachute 13 which is connected to the tail region 14 of the torpedo 11 by a shock absorbing device 15 and automatic disconnect means 16. The shock absorbing device comprises a length of undrawn polyester fibre fabric material of uncut velvet construction having two opposing face layers which are joined to each other by iterconnecting pile members of the kind as disclosed in British Patent No 1166245. At their one ends the face layers are secured the one to the rigging lines of the parachute and the other to the tail structure of the torpedo through the automatic disconnect means 16. In use the torpedo 11 is carried by an aircraft with the parachute stowed in a pack at the tail of the torpedo. After release from the aircraft the parachute is deployed automatically and both stabilizes and controls the rate of descent of the torpedo through the air. By this means the torpedo enters the water in a stable fashion and at a speed of typically 65 knots. As the torpedo dives into the water a cavity 17 is formed around the torpedo which collapses towards the parachute as a mixture of water and air and the parachute fills at leat partially with water as shown at B and as a result of the increased drag, as water replaces air from the parachute, increased retarding forces are applied to the torpedo.As a result of the forces developed the interconnecting pile members tear progressively and absorb energy thus preventing the level of retarding load applied to the torpedo from increasing to the point where it would damage the tail of the torpedo and/or the parachute. After entry of the torpedo into the water and stabilisation to a required attitude as at C, the automatic disconnect means 16 operate to disconnect the torpedo from the shock absorbing device and may be made to operate in accordance with various functions such as time, depth or from signals from sensing devices carried on the torpedo. Thus, in one example, a time sensitive device on the torpedo is triggered upon entry of the torpedo into the water and is operative after a predetermined time to set the torpedo drive motor in motion and the resulting rotation of the torpedo drive shaft acts simply to unscrew itself from the shock absorbing means. Using this apparatus it is found that in the case of a particular torpedo the depth of penetration of the torpedo into the water varied from 20 to 26 feet with repeatable accuracy thus providing a shallow water capability. Furthermore, the torpedo was always in a controlled stable condition in the water as at C which is advantageous for enabling the sensing devices on the torpedo to take over to control the torpedo on its further run as at D. In general the use of drogues or drag plates as drag means is not effective where the speed of entry of a device into the water is sufficient to cause a cavity region of air or a foam of air bubbles and water to exist behind and adjacent the tail of the device as at B. However, in cases where the speed of entry may be relatively low as in the case of a torpedo fired from a ship torpedo tube the use of such drag devices in place of the parachute may be possible. The invention may also be used for the control of devices other than torpedos. WHAT I CLAIM IS:

1. Apparatus for the control in air and water of a device launched through the air to the water comprising drag means, shock absorbing means and automatic disconnect means, the shock absorbing means and the disconnect means connecting the drag means to the device, wherein, the drag means retard and stabilize it, during passage of the device through the air after entry of the device into water the drag means react with the water to decelerate and stabilize the device in the water and the shock absorbing means yield so that excessive loads on the device and the drag means are avoided, and subsequently the disconnect means releases the drag means from the device.

2. Apparatus according to claim 1, wherein the automatic disconnect means are controlled by a time sensitive device triggered upon impact of the device with the water.

3. Apparatus according to claim 1, or claim 2 and wherein the drag means comprises a parachute.

4. Apparatus according to claim 1, 2 or claim 3 and wherein the shock absorbing means comprises a fabric material as disclosed in British Patent No 1166245.

5. Apparatus for the control in air and water of a device launched through the air to the water substantially as described herein with reference to and as illustrated by the accompanying diagrammatic drawings.