US20100275763A1

US20100275763A1 - Nozzle

Info

Publication number: US20100275763A1
Application number: US12/003,319
Authority: US
Inventors: Andreas Malmlof; Mili Dugalic
Original assignee: Saab AB
Current assignee: Saab AB
Priority date: 2006-12-22
Filing date: 2007-12-21
Publication date: 2010-11-04
Also published as: EP1936317B1; ATE448459T1; EP1936317A1; DE602006010422D1; ES2333666T3

Abstract

A nozzle for a weapon including a launcher which constitutes a guide for a projectile or missile. The nozzle includes a wall, a first opening connected to the launcher and a second opening. The area of the first opening is smaller than the area of the second opening. The nozzle a pressure reducer for reducing a pressure of gases from the projectile inside and behind the nozzle when firing the weapon. A circumferential element is arranged at the first opening of the nozzle. An opening area of the circumferential element is less than the area of the first opening of the nozzle.

Description

FIELD OF THE INVENTION

The present invention relates to a nozzle for a weapon comprising a launcher which constitutes a guide for a projectile or missile; the nozzle comprises a wall, a first opening connected to the launcher and a second opening. The area of the first opening is smaller than the area of the second opening.

BACKGROUND OF THE INVENTION

Weapons such as handheld weapons from which a projectile or missiles are shot are in some cases provided with a launcher without a nozzle. The nozzle is arranged in the rear end of a launcher which constitutes a guide for the projectile. When the weapon is fired the projectile is guided by the launcher and leaves the front end of the launcher towards a target. Also a flame is created by the projectile when the weapon is fired. The flame creates gases of high temperature which expands at the rear end of the launcher of the weapon, through the nozzle. In this connection also a high pressure being created behind the launcher.
In order to decrease the recoil and thus make possible an increase in weight of the projectile without excessively high pressure being created behind the launcher, it has been known for many years to introduce what is known as a countermass. The countermass may be a liquid enclosed in a container arranged in the launcher behind the projectile. The countermass in form of liquid leaves the rear end of the weapon when the weapon is fired and thereby produces a pressure-reducing effect adjacent to the weapon when the countermass expands and disintegrates. Documents SE 0301626-8 and SE 0301627-6 discloses examples of such countermass containers for weapons.
However, one drawback is that when the countermass is a liquid, a cloud is formed around the weapon, which makes it difficult to rapidly achieve a clear view of the target for firing the weapon again. Another drawback of using a countermass is that an asymmetrical flow may be created in the countermass container, which can produce great shear forces on the weapon. Also, pieces from the container may come away from the container and constitute a risk behind the weapon.

SUMMARY OF THE INVENTION

The objective problem to be solved by the present invention is to avoid that a liquid cloud is formed around the weapon when the weapon is fired.
Another objective problem to be solved by the present invention is to reduce the pressure behind a weapon
Yet another objective problem to be solved by the present invention is to eliminate the need of a countermass in a weapon.
Yet another objective problem to be solved by the present invention is to reduce the recoil in the forward direction.
Ambient air is used to reduce the temperature of the hot gases which leaves the rear end of the weapon through the nozzle. When ambient air is introduced in the hot gases, energy is transformed which reduces also the pressure inside the hot gases. Since the pressure is reduced also the recoil on the weapon is reduced. The ambient air is introduced in the hot gases by the means provided at the nozzle.
According to one embodiment said means is a number of third openings arranged in the wall of the nozzle at the area of the second opening. When the weapon is fired ambient air is sucked in through the third openings by the gases that flow through the nozzle. The ambient air reduces the temperature of the gases from the projectile. According to this first embodiment the gases within the nozzle are over expanded.
According to another embodiment said means is a spoiler is arranged substantially inside the nozzle in the area of the second opening. When the weapon is fired the gases from the projectile passes through the nozzle with high velocity. The spoiler creates a low pressure on one of its surfaces when the gases pass the spoiler. The low pressure reduces the temperature of the gases. Also, the low pressure created by the spoiler leads to that ambient air is sucked in through the second opening of the nozzle and thereby reduces the temperature of the gases from the projectile. According to this embodiment the gases within the nozzle are under expanded.
According to yet another embodiment of the invention a circumferential element is arranged at the first opening of the nozzle. The circumferential element has an opening area which is less than the area of the first opening of the nozzle. The effect achieved by this element is that recoil in the forward direction is reduced when the weapon is fired.
When a nozzle provided with said means is used in a weapon a liquid cloud is not formed around the weapon when the weapon is fired since there is no need for a countermass. Therefore it is possible to rapidly firing the weapon again since no liquid cloud restricts the view of the target.
Also, a weapon with such a nozzle is easy to handle, cost effective when manufacturing and have no problems with shear forces which may occur when using a countermass.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages and features of the invention can be derived from the following detailed description of exemplary embodiments of the invention, with reference to the drawings.

FIG. 1 shows a section view of a nozzle according to a first embodiment of the invention,

FIG. 2 shows a view in perspective of the nozzle according to the first embodiment,

FIG. 3 shows a section view of a nozzle according to a second embodiment of the invention,

FIG. 4 shows a view in perspective of the nozzle according to the second embodiment, and

FIG. 5 shows a section view of a nozzle according to the second embodiment of the invention with a reduced pressure area indicated.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 shows a section view of a nozzle 1 according to a first embodiment of the invention. The nozzle 1 is arranged on a weapon 2, which comprises a launcher 4 which constitutes a guide for a projectile or missile 6. The launcher 4 and the projectile 6 are schematically disclosed in the figure. The nozzle 1 comprises a circumferential cone shaped wall 8, which defines a first opening 10 and a second opening 12. The first opening 10 of the nozzle 1 is connected to the launcher 4. The first opening 10 is an interface section or a throat of the nozzle 1 and in this case the interface section is in the substantially same plane as the throat. The area of the first opening 10 is smaller than the area of the second opening 12, so that the nozzle has the form of a funnel. The first and second openings 10, 12 are substantially cylindrical and are arranged substantially concentric with each others. The second opening 2 of the nozzle is an exit section.
A gas generator 14 is arranged in the area of the first opening 10. When the weapon 2 is fired a pressure is exerted on the gas generator 14 from the projectile 6. The diameter of the gas generator 14 is so dimensioned that the forces from the projectile 6 on the gas generator 14 and the nozzle 1 will reduce the recoil when the weapon 2 is fired. The gas generator 14 is attached to the launcher 4 by fastening means (not disclosed).
The nozzle 1 is provided with means 18 for reducing the pressure of gases 16 from the projectile 6 inside and behind the nozzle 1 when firing the weapon 2. Said means 18 is arranged at the second opening 12 of the nozzle 1.
According to the first embodiment said means 18 is a number of third openings 18 arranged in the wall 8 of the nozzle 1 at the area of the second opening 12. Which is disclosed in FIG. 2 said third openings 18 are arranged circumferential in a row in the wall 8 of the nozzle 1. The area of each third opening 18 is substantially equal and the area of each third opening 18 is essentially smaller than the second opening 12. Preferably, the third openings 18 are so arranged in the wall 8 of the nozzle 1 that a centre axis 20 of each third opening 18 will intersect each other in a common point P, which is indicted in FIG. 1.
When the weapon 2 is fired ambient air is sucked in through the third openings 18 by the gases 16 that flow through the nozzle 1. The ambient air reduces the temperature of the gases 16 from the projectile 6. When ambient air is introduced in the hot gases 16, energy is transformed which reduces the pressure inside the hot gases 16. Since the pressure is reduced also the recoil on the weapon 2 is reduced.
According to a second embodiment of the invention disclosed in FIG. 3 said means 18 is a spoiler 18′ arranged substantially inside the nozzle 1 in the area of the second opening 12. The spoiler 18′ is so arranged inside the nozzle 1 that an opening gap 22 is created between the wall 8 of the nozzle 1 and the spoiler 18′.
FIG. 4 shows a perspective view of the second embodiment. The spoiler 18′ has a form which is substantial circular and is connected to the wall 8 by distance elements 24. Preferably, the distance elements 24 have an aerodynamic form that not disturbs the flow of the gases 16.
When the weapon 2 is fired the gases 16 from the projectile 6 passes through the nozzle 1 with high velocity. The spoiler 18′ creates a low pressure on one of its surfaces when the gases 16 pass the spoiler 18′, which is indicated in FIG. 5. The low pressure reduces the temperature of the gases 16 and the low pressure LP created by the spoiler 18′ also leads to that ambient air is sucked in through the second opening 12 of the nozzle 1 and thereby reduces the temperature of the gases 16 from the projectile 6.
According to a third embodiment of the invention a circumferential element 26 is arranged at the first opening 10 of the nozzle 1. This circumferential element 26 is disclosed in FIG. 1. An opening area 28 of the circumferential element 26 is less than the area of the first opening 10 of nozzle 1. Hence, a circumferential abutment 30 or edge is created by the element 26. When the weapon 2 is fired a pressure from the gases 16 created by the projectile 6 is exerted on the element 26. Therefore, recoil in the forward direction of the weapon 2 is reduced.

Claims

1. A nozzle for a weapon comprising a launcher which provides a guide for a projectile or missile, the nozzle comprising:

a funnel-shaped wall,

a first opening connected to the launcher,

a second opening, wherein an area of the first opening is smaller than an area of the second opening, and

a spoiler arranged inside the nozzle in an area of the second opening so as to form an opening between the spoiler and the funnel-shaped wall, the spoiler reducing a pressure of gases from the projectile or missile inside and behind the nozzle when firing the weapon.

2. The nozzle according to claim 1, wherein the opening between the spoiler and the second opening of the nozzle is annular.

3. The nozzle according to claim 1, wherein the first and second openings are substantially cylindrical.

4. The nozzle according to claim 1, wherein the first and second openings are arranged substantially concentric with each other.

5. (canceled)

6. The nozzle according to claim 1, further comprising:

a gas generator arranged in the area of the first opening.

7-13. (canceled)

14. The nozzle according to claim 1, wherein the spoiler has a form which is substantial circular.

15. The nozzle according to claim 1, wherein the spoiler is connected to the wall by distance elements.

16. The nozzle according to claim 1, further comprising:

a circumferential element arranged at the first opening of the nozzle, wherein an opening area of the circumferential element is less than the area of the first opening of the nozzle.