Re: Gauss Weapons

At 10:34 AM 8/26/98 +0100, Jon White wrote:

>>This may not be all that new but friends in low places tell me that
the
>>British Army has a working Gauss artillery piece.

>Hmm.. Is there any distinct advantage to a Gauss artillery piece
compared
>to a standard chemical or binary propellant one? I can understand a
gauss
>gun would have advantages in a tank - caseless ammo, less smoke on
firing
>etc, but an arty piece is nowhere near the enemy and is only really
>vunerable to counterbattery fire and air interdiction raids. Would a
Gauss
>weapon have a longer range than a chemical powered one necessarily?
Higher
>rate of fire? By definition they are going to be heavier of themselves
than
>standard arty pieces because of the magnets, capacitors etc..

When I was a college sophomore a little over ten years ago, I took a
Journalism class where I got to interview one of the administrators at
The
University of Texas' Center for Electromechanics.

One of the projects they were working on in connection with Reagan's
Strategic Defense Initiative was the railgun.  (As I understand it, a
gauss
weapon would be a "coilgun" -- a close relative of the railgun.  Anyone
have any details on the distinction between them?)

Here are a few of the details I still remember:

The first generation railguns were one-shot affairs; a chemical
explosive
charge was used to produce the electrical pulse that powered it (don't
recall how, exactly) but destroyed the device in the process.

The next generation of railgun (the first one that UT built) used 6
capacitors to charge it.  Each of these capacitors was about 6-7 feet
tall
and about 2 feet in diameter.  It was capable of propelling a 1 cm
plastic
cube (lined on one face with metal foil) at a muzzle velocity of 2-3
times
that of the best chemical propellant weapons.  They showed me one of the
targets they fired it at; a foot-square plate of aluminum about an inch
thick...with a jagged hole about the size of a large man's fist right
through it.  The drawback of this model was the amount of time it took
to
recharge the capacitors.

To solve this problem, they were developing on a new type of multi-cycle
electrical generator that they called a "compulsator."	Instead of
producing a steady flow of current like a normal generator, this device
was
able to produce pulses of current comparable to that previously stored
in
those huge capacitors ...several times a second.

(I did a quick search on "compulsator", here the first URL that came up.
It has info on some of the prototypes they built:
<http://www.pkd.com/pulsed.htm>

With the compulsator, they were able to build a railgun with machine-gun
like rates of fire; I remember being amused that they measured the rate
of
fire in "Hertz" since it was directly related to the frequency of the
electrical pulses produced by the compulsator.	IIRC, the limiting
factor
for the rate of fire was the loading mechanism rather than the
generator.

Although they were doing this research in connection with SDI, they had
already noted the potential for anti-tank weapons as well.  Another of
the
advantages that an electromagnetic weapon will have besides high rate of
fire and muzzle velocity (and correspondingly correspondingly greater
range
and accuracy) is smaller ammunition loads and elimination of the need
for
chemical propellants.  While this is somewhat offset by the larger
powerplant and fuel load required, there is a definite logistical
advantage
to eliminating chemical propellants in favor extra fuel.  At that point
you
start getting into questions of what has the greatest amount of stored
chemical energy, a kilo of diesel fuel or a kilo of cordite (or binary
propellant or whatever).

In a sci-fi setting, railguns and gauss weapons would be ideal for
vehicles
equipped with fusion powerplants.  Ammo could also become less
problematic;
there is a scene in one of the "Fifth Foreign Legion" books where the
heroes are using some little widget to produce needles for their gauss
rifles out of scrap metal...one of their wrecked APCs, IIRC.  :)

Jeff