US3721196A

US3721196A - Chaff dispensing system

Info

Publication number: US3721196A
Application number: US00064916A
Authority: US
Inventors: E Willis; L Musser; J Seagraves
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1970-07-30
Filing date: 1970-07-30
Publication date: 1973-03-20
Anticipated expiration: 1990-03-20

Abstract

A method and apparatus for dispensing chaff from a rocket delivered warhead. A chaff head is explosively opened a predetermined time after the rocket is fired. This exposes the chaff to the air which quickly disperses it into a cloud.

Description

United States Patent Willis et al. 1March 20, 1973 CHAFF DISPENSING SYSTEM [56] References Cited [75] Inventors: Edward O. Willis, Copley; Lester UNITED STATES PATENTS W. Musser, Jr., Barberton' James E.

. 3,023,703 3/1962 Beatty ..102/49.4 Seagmves Unlomown of 01m 3,070,018 12/1962 Fahl ..102 495 [73] Assignee: The United States of America 35 3,167,016 1/1965 Czerwinski et al.. .....102/49.4 represented by the Secretary of the 3,318,241 5/1967 Gould ..102/49 5 Navy 3,374,740 3/1968 Voda ..102/49.5

[221 Ffled: July 1970 Primary ExaminerVer1in R. Pendegrass [2 Applo.1 64,916 Attorney-R. S. Sciascia and Thomas 0. Watson, Jr.

52 us. Cl. ..102/89, 102/495, 102/63, ABSTRACT 343/18 E A method and apparatus for dispensing chaff from a [2g] ..F42b 13/42 rocket delivered warhead A chaff head is explosively 1 le 0 opened a predetermined time after the rocket is fired.

This exposes the chaff to the air which quickly disperses it into a cloud.

2 Claims, 3 Drawing Figures PATENTEDMARZO I973 INVENTORS EDWARD 0. WILL/S LESTER M MU$$ER,JR.

JAMES E. SEAGRAVES \%M ATTORNEY CHAFF DISPENSING SYSTEM STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION This invention relates generally to radar decoy systems and more particularly to systems for the delivery and deployment of chaff.

It has long been recognized that the attention of enemy radar may be diverted by creating a false target. The use of a cloud of chaff has proven to be a very effective method of creating false radar targets. However, problems in both the delivery and deployment of the chaff have been encountered.

SUMMARY OF THE INVENTION The present invention provides an efficient chaff delivery and deployment system. The chaff is contained within a generally cylindrical chaff decoy head which is made in two halves. A nose assembly mounted at one end of the chaff decoy head contains a variable time fuze and an explosive cord. The chaff head and nose assembly are mounted on a conventional surface to airto-surface.

Prior to launch, the variable time fuze is set in accordance with the launch angle and the distance from the launching point at which the chaff is to be deployed. At launch, the fuze is armed and begins its timing. A predetermined time after launch, the fuze causes the explosive cord to be set off. This operates on the two halves of the chaff head to force them apart and exposes the chaff to the air. The action of the air quickly disperses the chaff into a cloud.

OBJECTS OF THE INVENTION An object of the present invention is the provision of a system for diverting enemy radar attention by creating a false target.

Another object is to provide an efficient chaff delivery and deployment system.

A further object of the invention is the provision of a system capable of dispensing chaff at preselected points in space.

The exact nature of this invention as well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the chaff delivery rocket at various points in time from launch to chaff deployment.

FIG. 2 shows the chaff rocket assembly configuration at deployment.

FIG. 3 shows a partial cutaway of the chaff decoy head and nose assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the operational characteristics of a preferred embodiment of the present invention. The chaff rocket is shown in flight from the launching tube to chaff dispersion. As the chaff rocket approaches the point in space corresponding to the time setting of the variable time fuze, the chaff head begins to open. Air acting upon the exposed chaff causes it to disperse into a cloud.

The configuration of the chaff rocket assembly, at the point in time corresponding to the setting of the variable time fuze, is illustrated in FIG. 2. Here, the two body halves 11 of the chaff decoy head 12 (see FIG. 3) are shown partially pivoted about hinge like members 13. The members 13 are part of an adapter 14 which serves to join the two body halves 11 to a rocket motor 16. The rocket motor 16 may be of any conventional type suitable for the intended use. Similarly, it is intended that the adapter 14 take whatever form required to connect the two body halves 11 to the selected rocket motor 16.

Referring now to FIG. 3, the two body halves 11 are shown joined to form a generally cylindrical body 12 having an internal chamber. The body 12 is designated as a chaff decoy head as its internal chamber contains the chaff material. It is intended that the chaff decoy head 12 will contain approximately 56 chaff load segments. This chaff material is an aluminum alloy coated on one side with silicone. The coating produces a smooth film that reduces friction in the chaff load. It is contemplated that other chaff types and loading configurations may be employed without exceeding the scope of the invention.

The joint 18 formed by the joined body halves 11 is sealed in any manner consistent with its separation upon chaff deployment. A frangible shroud 19 (shown partially cutaway) surrounds the chaff decoy head 12 at its point of connection with the adapter 14.

The nose assembly 21 contains a safety and arming device (not shown) and a mechanical time movement (not shown) which may be of the type typically used in mechanical variable time fuzes. The safety and arming device is acceleration sensitive and will arm the fuze when launch conditions are maintained for a sufficient time. It is essentially a time delayed device that will operate only when the chaff head is subjected to steady forward acceleration forces exceeding 19g. The use of such a device prevents accidental arming and detonation during handling and storage and automatically restores the fuze to a safe condition should the propulsion system fail during the arming interval. The timing movement is a variable-delay mechanism that allows the time period between arming and chaff dispersion to be preset manually before launch. Delays are set by rotating the nose of the fuze with respect to the fuze body. The timing delay and launch angle are varied to select the chaff dispersion location.

After launch and at the end of the preset delay, the timing movement releases the primer striker 23, thereby igniting a booster 24 which sets off two explosive cords 25. These two cords are in the forward end of the chaff decoy head 12 and are butted at two places in their circumferential wrap. If one cord fails to be ignited by the booster 24, this butting arrangement will cause the other cord to be initiated. The nose assembly 21 and chaff decoy head 12 may be joined in any suitable manner consistent with the requirement that they be separable (see FIG. 2) upon initiation of the explosive cords 25.

In operation, the mechanical variable time fuze is preset to disperse the chaff load at the desired point. Upon launch, the safety and arming device will arm the time fuze to begin the timing sequence. At the end of the preset delay, the timing movement releases the primer striker 23 thereby igniting the booster 24 and setting off the two explosive cords 25. The action of the explosive cords 25 causes the body halves 11 of the chaff decoy head 12 to separate thereby exposing the chaff, within the internal chamber of the chaff decoy head, to the air. The action of the air quickly disperses the chaff into a cloud. When a number of chaff heads are released in a controlled area, the chaff can produce radar images to create either single or multiple decoys as required by a tactical situation.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A chaff dispensing apparatus which comprises:

a. two body halves joined to each other to form a ho!- low chaff decoy head;

b. an adapter assembly hingedly connected to each of the two body halves;

0. explosive cord separating means for explosively separating the two body halves of the chaff decoy head, thereby causing the two body halves to pivot about the adapter assembly; and

Claims

1. A chaff dispensing apparatus which comprises: a. two body halves joined to each other to form a hollow chaff decoy head; b. an adapter assembly hingedly connected to each of the two body halves; c. explosive cord separating means for explosively separating the two body halves of the chaff decoy head, thereby causing the two body halves to pivot about the adapter assembly; and d. a nose assembly connected to the chaff decoy head adjacent the explosive cord separating means, said nose assembly containing a variable time fuze for initiating the explosive cord separating means.

2. The chaff deployment and dispersion apparatus of claim 1 wherein a frangible shroud surrounds a portion of said body halves adjacent said adapter assembly.