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From: mullermb@mentor.cc.purdue.edu (Mark Muller)
Newsgroups: sci.military
Subject: Re: Tank killing crowbars
Message-ID: <1991Feb19.031431.15981@cbnews.att.com>
Date: 19 Feb 91 03:14:31 GMT
References: <1991Feb13.032640.27454@cbnews.att.com> <1991Feb15.073525.12636@cbnews.att.com> <1991Feb18.051806.8964@cbnews.att.com>
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From: mullermb@mentor.cc.purdue.edu (Mark Muller)

In article <1991Feb18.051806.8964@cbnews.att.com> john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) writes:

   [discussion of LTV's kinetic kill missile and demo deleted]
>
>Sorry, I don't quite believe this.  By mach 5 I assume you mean
>5 times the speed of sound in air, so mach 5 means about 1.5 km/sec.  That
>is the very, very low end of the hypervelocity regime.  I am skeptical
>that you can get a penetrator to go through a tank at that velocity.  It
>might penetrate to the interior if you have thin enough armor, but I doubt
>seriously it would survive intact enough to ever get out again.  Think
>about it, the interior of a tank is the ultimate spaced armor!  To be
>honest, I am not all THAT confident you would even penetrate into the first
>tank in the real world against good modern armor such as the Soviets have.
>However, I wouldn't care to test that theory by sitting in the tank and having 
>you fire this at me, but I would probably be willing to sit in the second
>tank.
>
    However, Mach 5 is also about the velocity of the penetrator from a current
    M1A1 tank (I saw a chart in an issue of Armor Magazine about a year ago that
    had muzzle velocities of tank guns, with the 120mm gun in the M1A1 being at 
    about 5000 fps, which equates to Mach 4.5) which should kill current Soviet
    tanks quite well.  I say this since the 120mm is supposed to be an 
    improvement over the 105mm gun, which, according to the Isrealis, had no
    problem penetrating with Syrian T-72's in Lebanon.  Of course, one could say
    that T-74's and T-80's have much improved armor, in both quality and 
    quantity, but this is hard to tell, and unlikely to be as significant that
    many people would have you believe (if desired, I could discuss this subject
    in more depth).  Of course, in the case of tank rounds, by the time they
    impact their targets, there speed is reduced by aerodynamic drag, whereas
    the missile would possibly still be getting thrust from it engine.

    A lot of penetration, however, has to do not with absolute velocity, but
    with the energy concentration of the impact, which is simply the total
    kinetic energy per unit area of the impact.  Thus if the missile is long
    and heavy, its penetration at an impact of Mach 5 could possibly surpass
    that of the typical tank gun penetrator.

[mod.note: One advantage of such a missile would be that it would allow
the use of longer penetrators than could be fired from a tank gun. (The
tremendous acceleration in a gun limits the length the penetrator can be;
the missile would probably have substantially lower acceleration).
Penetration is approximately proportional to the length of the penetrator,
so one might expect better performance from such missiles than one could
get from a gun with the same velocity. - Bill ]

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*  Mark Muller          Aeronautics and Astronautics Engineering              *
*  Undergraduate        Purdue University                                     *
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