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From: thos@softway.sw.oz.au (Thomas Cohen)
Newsgroups: sci.military
Subject: Re: About those Ugly M-60's
Summary: HEAT rounds and kinetic energy
Message-ID: <1991Feb7.012722.118@cbnews.att.com>
Date: 7 Feb 91 01:27:22 GMT
References: <1991Feb5.043146.6128@cbnews.att.com>
Sender: military@cbnews.att.com (William B. Thacker)
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From: thos@softway.sw.oz.au (Thomas Cohen)
In article <1991Feb5.043146.6128@cbnews.att.com> JEWELLLW@VM.CC.PURDUE.EDU (Larry W. Jewell) writes:
>
>	[ lots of stuff about reactive armour and HEAT rounds ]
>
>the tank.  It works by disrupting the hot gas jet put out by a HEAT
>(High Explosive Anti Tank) round.  These rounds work by exploding a
>shaped charge about a foot away from the armor, which forms a very
>thin, superhot gas jet which then burns through the tank's armor.
>(This is the reason HEAT rounds and antitank missiles such as the TOW
>have a foot long spike on the front-to get correct standoff distance
>for the jet formation.  But I digress...)  The idea behind reactive

While the standard explanation has been for years that a hot stream of
gas 'hoses' its way through the armour, Ian Hogg in his "Encyclopedia
of Ammunition" says that the 'slug' which was the metal lining of the
shaped charge has a velocity ~32 000 fps (which is somewhat faster than
the speed of detonation of the explosive) and with this velocity, it 
penetrates using its kinetic energy. He also admits that that is simplified
so I am a little bit confused. Are there any real-type ammunition experts
out there who can shed light on this? And also how the speed of the slug
is faster than the detonation speed?

Bunker killing:

In another thread, people were talking about penetrating concrete bunkers
with whatever came to hand. In the same book, there is mention of a 
"Rochling" concrete piercing shell, designed during WW2 in Germany,
and used early in the war. The shells were made from some hard metal
(Vanadium or Tungsten &c) and they didn't make many before they realized
they needed the metal to make machine tools. Hitler was also paranoid
about the Allies finding ones that hadn't exploded and had to give permission
for them to be used. Accounts show that they were very effective when they
were used : one test against the Maginot Line fortifications (after they'd
been captured) penetrated 5m of earth, 36m of concrete, a layer of broken
stone (doesn't say how thick) through a chamber and 5m into the floor of
the chamber! It wasn't fused so it did not explode (if it had been fused
correctly it would have exploded in the chamber).
Which brings to mind a question :
How long does it take 36m of concrete to cure, or would they put it down
in layers?

-- 
thos cohen  				       |Softway Pty Ltd
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