Re: Yet Another Rail Gun Question

The Ghost In The Machine <ewill@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
news:jg2vn2-54b.ln1@xxxxxxxxxxxxxxxxxxxxxxxxxxx:

> Answer some basic engineering questions

> [1] Length of barrel?

Whatever is realistic for an M1A2, say 10'.

> [2] Power along barrel?

Whatever can be achieved by a manageable number of OTS welding supplies,
say 200KW total.

> [3] Desired bullet mass?

50 caliber stainless. What brand of steel has the lowest resistivity?

> [4] Desired bullet speed?

Whatever would be considered by the Pentagon to sufficiently outclass a
chemical gun to make it worth buying, say 2x a SOTA 50 calibre chemical
gun.

> I'd also have to work out thermodynamic considerations,
> as well; that bullet is absorbing energy from the current
> feeding the gun, and it might get a little warm from the
> eddy currents.

"A little" warm is no trouble, since the bullet will soon be the enemy's
problem. Must to keep it from melting, though.

> Or, perhaps, the wire surrounding the
> barrel will get *very* warm from the current feeding it.
> That, of course, depends on the wire gauge you're intending
> to use.

A manageable number of, say, 1" cables. 20 might be a reasonable upper
limit.

> And then there's the issue of how one keeps the projectile
> on the straight and narrow.

Rifling

> The few designs I've seen (on some TV shows)

What tv shows are these, and where can I see them?

> suggest that the projectile is covered
> with a casing that accelerates with the projectile, then
> separates, allowing freeflight to the target after the
> projectile leaves the gun and the casings to fly off in
> a slightly different direction

This doesn't look too smart. If you've got two objects flying in
different directions, neither one will be on the straight and narrow.

> (I'd not want to stand too close to the firing nozzle).

But you didn't want to do that before you added the casing. I'm betting
that there's a very nasty arc formed where the bullet departs the
muzzle.

> I have no idea how the projectile is kept from tumbling after
> released from its casing.

As I said, rifling.
.

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