PENETRATOR ARROW PROJECTILE

Abstract: A penetrator arrow projectile for launching by use of a launcher projectile which comprises a propellant charge and which may be separated from the arrow projectile in the trajectory. A "base-bleed" charge (2) is situated rearwardmost on the arrow projectile (1), in order to be ignited by means of an igniter device (3) in connection with the separation from the launcher projectile, which may comprise a forward igniter device for igniting the "base-bleed" charge (2). The launcher projectile may also comprise a mechanism for retaining the arrow projectile (1) on the forward end and for releasing the arrow projectile in the trajectory.

Description: Penetrator arrow projectile. Field of the invention. The present invention relates to a so-called penetrator arrow projectile, i.e. a slim projectile, which constitutes a penetrator, for launching by use of a launcher projectile which comprises a propellant charge and which may be separated from the arrow projectile in the trajectory. Prior art. It is known to launch such arrow projectiles from a gun, the projectile being a subcalibre relatively to the weapon tube being used, in that a divisible liner is mounted on the projectile and constitutes a thrust surface during the launching. The liner separates from the projectile in the trajectory, and the projectile continues towards the target alone. The projectile is used to penetrate a target, i.e. to enter into and damage the target, which for instance may be an armoured vehicle or a helicopter. DE 4018385 shows a subcalibre practice projectile having a liner in the form of a forward disc and a rearward cone, whereby the disc and the cone guide the projectile in the weapon tube. The disc also constitutes a seal for the propellant gases in the weapon tube, and it is divivible and releases in the trajectory of the projectile, while the cone shall accompany the projectile and decrease the braking effect caused by the air, and a so-called "base-bleed" charge is situated rearwardmost on the cone, in order to emit a gas which reduces the drag on the projectile caused by the underpressure and the formation of a vortex behind the cone. The "base-bleed" charge, which is ignited during the launching and burns while the projectile is in the trajectory, develops a gas which mainly shall only "fill" the region behind the cone in order to reduce the underpressure and the vortex formation, and has little or no effect as propellant charge. Summary of the invention. The projectile according to the invention is characterized in that a "base-bleed" charge is situated rearwardmost on the arrow projectile, in order to be ignited by means of an igniter device in connection with the separation from the launcher projectile. The arrow projectile is slim compared with the launcher projectile, and has a small air resistance, and the velocity in the trajectory is also maintained by the "base-bleed" charge which burns and emits a gas. Thereby is achieved a large impact velocity and increased range. Thus, the "base-bleed" charge is not ignited during the launching, because this would have a small effect as long as the launcher projectile propels the arrow projectile. When the launcher projectile ceases to act as propellant projectile, the launcher projectile is released, and the slimmer arrow projectile continues in the trajectory while the "base- bleed" charge burns. A rocket motor can be used as launcher projectile. The separation between the two projectiles may actuate an igniter device for the "base- bleed" charge, but ignition may also be achieved in another manner, for instance by timing relatively to the moment of launching. The igniter device may be situated in the launcher projectile. The invention will in the following be explained more detailed by means of examples, shown on the accompanying drawing. Explanation of the drawing. Fig. 1 shows an embodiment of the rear end of the arrow projectile according to the invention. Fig. 2 shows another embodiment of the rear end of the arrow projectile. Fig. 3 shows an arrow projectile. Fig. 4 shows the forward end of a rocket motor, carrying an arrow projectile. Description of examples of embodiments. In the rear end of an arrow projectile 1 shown in the Figs. 1 and 2 is mounted a "base- bleed" charge 2, which can develop a gas by combustion. Along the center of the charge 2 is a cavity, and the charge is adapted to burn radially outwardly from the cavity. Alternatively a charge may be used which burn from the rear end or a charge with both types of combustion. In order to ignite the charge at a specific point of time after the launching an igniter 3 is mounted, shown coupled to a wire which transmits an ignition signal from for instance an electronic unit in the forward part of the projectile. A mechanical igniter device may also be used. Optionally the igniter device may be mounted in a rocket motor used as launcher projectile for the arrow projectile. In a rear plate 7 is in Fig. 1 shown a gasket 4 and a nozzle 5 mounted centrally, while Fig. 2 shows two gaskets 4 and two nozzles 5 diametrically opposite. Of course, a plurality of such gaskets and nozzled may be distributed along a circle or with another distribution. The gaskets protect the "base-bleed" charge against influence from for instance humidity in the air during storing. Moreover, Fig. 2 shows a sensor 12 on the outside of the rear plate 7, for possible communication and guidance. This sensor has no connection with the "base-bleed" function. During the combustion of the charge is developed a hot gas, which flows out through the rear plate 7. The gas builds up and maintains a pressure behind the projectile, whereby the braking effect ("drag") of the air is reduced, and the projectile will maintain its velocity to a larger degree than a projectile without such "base-bleed". In the Figs. 1 and 2 the "base-bleed" charge is shown in a cavity in the arrow projectile. The "base-bleed" charge may also be mounted in a separate unit which can be mounted on the rear end of the arrow projectile. Fig. 3 shows an arrow projectile according to the invention, with tail fins 11. These may for instance be in a number of four, distributed with a spacing of 90°. Fig. 4 shows the forward end of a rocket motor 8, which acts according to known principles and which is not explained more detailed. The rocket motor is ignited in a weapon and accelerates itself and the arrow projectile being coupled to the forward end of the motor 8, until the motor burns out and is released from the arrow projectile 1. At the front of the motor 8 is a retainer 9 for the arrow projectile 1. In the embodiment shown the arrow projectile has rear fins 11 , which may be distributed with 90° and are inserted in grooves in a nose portion 10 of the motor 8. The projectile shown is a subcalibre relatively to the rocket motor or another launcher projectile used.

Claims: Claims. 1. A penetrator arrow projectile for launching by use of a launcher projectile which comprises a propellant charge and which may be separated from the arrow projectile in the trajectory, and a "base-bleed" charge (2) situated rearwardmost on the arrow projectile (1), in order to be ignited by means of an igniter device (3) in connection with the separation from the launcher projectile (8). 2. A penetrator arrow projectile as claimed in claim 1 , comprising an electronic unit coupled to the igniter device, for controlling the ignition. 3. A penetrator arrow projectile as claimed in claim 1 , on which the "base-bleed" charge is situated in a separate unit coupled to the remainder of the projectile.

Inventors: FOSSUMSTUEN KAI, OERBEKK ERLAND, FOSSUMSTUEN, KAI, OERBEKK, ERLAND
Applicants: FOSSUMSTUEN KAI, NAMMO RAUFOSS AS, OERBEKK ERLAND, FOSSUMSTUEN, KAI, OERBEKK, ERLAND
Application year: 2001
Main classification: F42B10
IPC codes: F42B10