RE: Low Tech Scenarios

At 12:46 5/20/98, Glover, Owen wrote:
>Er to be a little more accurate; as the powder burns it produces an
>expanding gas. This forces the projectile out the barrel. The
>action/reaction is the projectile going in one direction against the
>mass of the rifle in the other. In your rail gun you may or may not
need
>a fully enclosed barrel. Therefore, expanding gas is not an issue?

Whether it's expanding gas, a magnetic pulse or gravitic repulsion, the
power source makes no difference. What does is that Newtonian physics
demands that for every action, there is an opposite and equal reaction.

The difference in eletromag vs. chemical recoil is not a quantitative
difference, but qualitative. Assuming that the projectiles from each
weapon
were equal in mass and accelerated to equal velocities in equal lengths
of
time, the average recoil will be equal (also assuming weapon mass is the
same.)

The difference is in the impulse of the recoil. Given the time it takes
to
accelerate the round to velocity, if we looked at a graph of force vs.
time
for the chemical round, there would be a huge initial spike that dropped
off very raplidly; in other words most of the chemical round's
acceleration
takes place in the first few milliseconds of the firing cycle.

Magnetic or grav-powered weapons, however, will over the same time have
a
force vs. time chart that looks like a long mesa; a pulse up to the
force
level, that level holds until the round leaves the barrel, then drops
off
almost instantly.

Someone firing a machinegun feels recoil as if it were a jackhammer;
repeated sharp impulses. Someone firing a full auto railgun would feel a
solid, steady push, with a rhythmic *absence* in recoil as each round
was
cycled into the chamber.

Of course now that I've gone into this massive diatribe, I'm wondering
why
I bothered. Just draw the chits and count 'em, ne? >^_^<

------------------------------------------------------------------------
------
Jim 'Jiji' Foster / jfoster@kansas.net / Jiji @ AnimeMUCK / TIP #28 /
PPIG #42

"That's the way we all begin," said Tom Platt. "The boys they make
believe
all the time till they've cheated 'emselves into bein' men, an' so till
they die--pretendin' and pretendin'."
    Rudyard Kipling, _Captains Courageous_