Re: HKP and the Kra'Vak

djwj insisted:

> >With you so far, except that the "small thin wire" is basically an
DSAP
> >rod penetrator.
> 
> No you aren't with me. The small thin wire is the Railgun equavilent
of
> gunpowder.

No, it is not. There's no way in hell a small thin wire can turn into
enough gas to pump up the pressure high enough to launch a tank-killing
missile - and pressure is the only means the plasma could accelerate
the projectile.

The railgun works because the *sabot* closes the circuit, and the
Lorenz force acts on the *sabot*. In those cases where there is plasma
- pretty much always for military-grade railguns, very rarely for
home-built paper-clip firing ones - the plasma conducts the current
from rail to sabot and vice versa, but that's it.

An ET gun works more or less as you describe it - the propellant is
vapourized when you run a strong current through it - but you use up to
several pounds of propellant rather than a "small thin wire". In ETC
guns the propellant reacts much like the gun powder of normal cannon,
but "only" when you run the current through it. 

Neither type has the continous conductive rails of a railgun, but both
can have a series of electrodes (isolated from one another) so you can
put the current through the barrel at the exact point you want rather
than everywhere at once. Those are the basic ideas, anyway - reality
tends to be a bit more complicated :-/

> >C'mon. You turn a short, thin wire into plasma, launch it, and think
> >that it'll be able to take out a tank some km away? It won't be too
fun
> >to stand close to the muzzle, though  - you might get some nasty
burns
> >if you do :-/ Probably worse for the gunner than for the target,
> >unfortunately.
> 
> You don't use the plasma as the projectile, the plasma accellerates
the
> penetrator rod the same way as gunpowder does.

That's not what you said elsewhere in your post, though :-/ See above.

> < something about speed errors >
> 
> You're right on that one, sorry

Not entirely - I forgot a factor 0.5. Still, 5c is a rather impressive
muzzle velocity too <g>
 
> > No, they don't. Current military *railguns* - only experimental so
far
> > - - use the Lorenz force (the one caused by the electrical current
> > flowing in the closed loop) to propel a fairly standard rod
penetrator
> > - - "fairly" standard, since the sabots have to be different from
the
> > ones you use in a normal DSAP tank round.
> 
> This sounds more like a Mass Driver than a Railgun.

All the term "Mass Driver" really says is that the device accelerates a
mass. All guns do that :-/ It is sometimes used to mean "a railgun
which launches big projectiles slowly"; this may be what you're
thinking of.
 
> >This is... wrong. Each action creates a reaction of equal size in
the
> >opposite direction; Newton's laws don't magically disappear just
> >because you use magnetism instead of explosives as a propellant.
> 
> You've never left heavy electrical construction equipment ungrounded 
> have you?

Please elaborate. I think I know what you're thinking of, but I'm not
sure. If you think of what I suspect, the entire conducting loop has to
be fixed - but that's not the case in a railgun, since the projectile
is part of the loop and is most definitely moving.

> I don't know how it works, I think it has something to do with 
> the action-reaction affecting the magnetic "event" rather than the
weapon
> directly, but asking a dedicated physisist (or Geo-Magnetist) about
this
> would be a better idea.

I've got a Masters degree in Engineering Physics. How dedicated do I
have to be to qualify?

> The railgun, originally, was a device for small particle
accelleration
> experiments, but like most scientific devices someone figured how it 
> could be used for war.

The railgun still causes a recoil. For small particle accelleration
experiments the recoil force is low enough not to be easily noticed,
but it is there.

Regards,

Oerjan Ohlson
oerjan.ohlson@telia.com

"Life is like a sewer.
  What you get out of it, depends on what you put into it."
- Hen3ry