DEVICE FOR AERODYNAMICALLY
STABILIZING A BOMBLET
BACKGROUND OF THE INVENTION
The present invention relates to submunitions consisting of bomblets, for example anti-vehicle and anti-personnel bomblets, which are released at altitude by a vector such as a dispenser shell.
The terminal effectiveness of these bomblets requires that, at the moment of their impact on the target, they be in a position as close as possible to a vertical position to ensure proper operation of the fusing device. Moreover, in the case of an anti-vehicular bomblet compris- 15 ing a hollow charge, the charge must be pointing downward.
It is therefore advantageous to control the attitude of the bomblet over its trajectory, and especially in its terminal phase 20
In a known manner, bomblets receive a stabilizing parachute ribbon in the form of a simple cloth ring of constant width, mounted on the upper end of the percussion fuse, which is in turn mounted so it is free to rotate with respect to the body of the bomblet. This 25 ribbon, as a result of its aerodynamic drag, tends to ensure proper alignment of the ribbon and bomblet body assembly, and therefore proper positioning of the bomblet as it falls. However, this proper positioning is not consistently achieved, due to the ribbon deploying 30 improperly or too late, resulting in functional problems upon impact.
In order to remedy the problem of the flight of bomblets as they are released, patent FR 2 650 661 proposes a stabilizing ribbon of variable width. The top of the 35 ribbon has a greater width in order to increase aerodynamic drag. Since the ribbons are generally produced by weaving, this device has the disadvantage of being more difficult to produce and thus more costly, while it does not produce a sufficient improvement in the flight 40 of the bomblet.
SUMMARY OF THE INVENTION
It is an object of the present invention to produce a stabilizing device for bomblets that is simple to produce 45 and low in cost, while providing a perceptible improvement in the flight of the bomblet on which it is installed.
This and other objects are achieved by providing a device that can be attached to the rear of the body of a bomblet to brake the bomblet aerodynamically and to 50 stabilize its attitude during descent, including a parachute ribbon of constant width forming a loop with a lengthwise dimension substantially greater than the lengthwise dimension of the body of the bomblet, characterized in that it includes, in the region where the 55 loop is fastened to the body, a member which extends to either side of the region and which acts to partially deploy the two ends of the loop in the vicinity of the region.
Because the member is present in the fastening region 60 of the loop, the loop is in a partially deployed position practically as soon as the bomblet is released. Complete deployment of the loop then occurs very rapidly in response to the speed of its fall.
According to a preferred embodiment, the partial 65 deployment member is a ribbon forming a supplementary loop with a lengthwise dimension substantially less than that of the loop being deployed.
According to another embodiment of the invention, the partial deployment member is a flexible strip, curved along its lengthwise dimension. The strip is attached to a portion of the ribbon of the loop being deployed, in the fastening region, and is integral with the ribbon.
Another object of the present invention is to provide a bomblet equipped with a braking and stabilizing device according to one of the embodiments above.
BRIEF DESCRIPTION OF THE DRAWINGS
Other details and advantages of the invention will become evident from the following detailed description of embodiments of the present invention, with reference to the attached drawings in which:
FIG. 1 is a perspective view of a bomblet comprising a stabilizing ribbon according to the invention;
FIG. 2 is a view of FIG. 1 from above;
FIG. 3 is a partial axial sectioned view, at enlarged scale, of the free end of the percussion fuse of FIG. 1;
FIG. 4 is a perspective view of a second embodiment of the invention;
FIG. 5 is a view of FIG. 3 from above; and
FIG. 6 is a front view of another embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
According to a first embodiment of the invention (FIGS. 1 to 3), a stabilizing ribbon 2 according to the invention is fastened onto a bomblet with an axis X—X'.
As an example, the bomblet can be of the type described in FR-A-2 650 662, and it is designed to be directed towards its target by means of a dispenser shell. A bomblet of this type comprises a percussion fuse 5 having a free end which is defined at the rear of the bomblet, onto which stabilizing ribbon 2 is fastened.
Stabilizing ribbon 2, made for example of a woven polyamide fiber such as nylon or rilsan, comprises a loop 3 having a lengthwise dimension substantially greater than that of bomblet body 1. Inside loop 3, stabilizing ribbon 2 comprises a small loop 4 with a lengthwise dimension substantially less than that of loop 3. Loops 3 and 4 are disposed substantially in the same axial plane with reference to bomblet body 1.
In a non-limiting manner, for a bomblet body 1 that is 90 mm long and 43 mm wide, it is possible to use a loop
3 whose ribbon has a total length of 500 mm, and a loop
4 whose ribbon has a total length of 125 mm. In both cases, the width of the ribbon is 19 mm.
The ribbons of loops 3 and 4 are fastened to one another by being sewn and/or adhesively bonded, and the fastening region, which thus has a double thickness, is in turn fastened to the free end of percussion fuse 5 (see FIG. 3). For this purpose, the percussion fuse has in its terminal part a cylindrical contraction 6 delimited by a peripheral shoulder 7. When a hole has been made in the double thickness area of. the fastening region of the ribbon, with a diameter slightly greater than that of cylindrical contraction 6, the two ribbon loops 3, 4 can be slid onto the latter, and allowed to rest on peripheral shoulder 7 so that the double thickness area is free to rotate.
The double thickness area is retained by a retaining washer 8, which is also free to rotate and is in turn retained on cylindrical part 6 by a washer 9 crimped onto end 5a of percussion fuse 5.
The above device operates as follows: