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From: thos@softway.sw.oz.au (Thomas Cohen)
Newsgroups: sci.military
Subject: Re: Tank busting munition.
Message-ID: <1991Mar15.041633.11087@cbnews.att.com>
Date: 15 Mar 91 04:16:33 GMT
References: <1991Mar12.224821.25366@cbnews.att.com>
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From: thos@softway.sw.oz.au (Thomas Cohen)
In <1991Mar12.224821.25366@cbnews.att.com> John Ramsden (jramsden@enh.Prime.Com) writes:
>It was a device which descended by parachute over an  area  supposedly
>containing  tanks,  and  as  it  approached  the ground it would start
>drifting sideways and precessing at the same  time,  like  a  gyrating
>sycamore  seed. This motion maximized the coverage of a camera or some
>sort of ground-scanning detector on the underside of the device.

>From my source book of choice - Ian Hogg's Encyclopedia of
Ammunition.

This is a SADARM - Search And Destroy Armor weapon. A US
remotely delivered munition (RDM) designed to destroy tanks at
long range. Three can be fitted into a 203mm or 155mm carrier
shell and are base ejected in the vicinity of the target, at
which point they hang from a parachute at 30 deg to the
vertical. As they descend they spin at about 4rps and a
millimetric wave sensor scans the ground for the signature of
a tank, which is hardwired into the munition. If it finds one,
it fires a self forming fragment at the target (see below).
The clever bit is, if it doesn't find a target, it will fall
to the ground and become a shaped charge mine. If I were a
tanker, I wouldn't like to follow an enemy through a region
where these had been used.

A Self Forming Fragment (SFF) is a development of the Schardin
effect. A flat cone shaped charge with a very heavy plate
liner rather than the thin liner of most shaped charges.
On detonation, the liner is not vaporized into a jet, but
converted to a slug-shaped missile which is projected at about
1200 m/s as a kinetic energy projectile. As these are used at
usually around 50m, velocity loss is minimal. Penetration is
good, but not as good as a well designed APDS round.

A bit more on millimetric wave sensing - A form of passive
millimetric wave radar, based on the fact that high frequency
radar approaches the infra red and takes on some of the
characteristics of optical frequencies. At these frequencies,
gound object emit radiation which is largely due to their
reflectance of the colour temperature of the sky. The earth is
fairly uniform, but tanks stand out quite nicely thank you.


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