Re: GEV and Grav Vehicles

On 30-Nov-99 at 20:59, Allan Goodall (agoodall@interlog.com) wrote:
 
> Sorry, yes you get recoil. It just won't be much of a problem.
> 
> Remember, energy is mv**2, but momentum is mv. In other words, if you
have
> a very small projectile and accelerate it relatively slowly, you will
> build up a lot of energy without much reverse momentum. The "v"
component
> would be more important than the mass component. The launcher and
vehicle
> would have a lot of mass compared to the projectile. I think it was in
the
> end of Gibson's Mona Lisa Overdrive that a mass driver fired from a
blimp.
> Recoil wasn't much of a problem.

The easiest way to think of this is the kinetic energy (mv**2) of the
projectile will be the _same_ as the kinetic energy of the firing
platform.  So yes, it is a problem, no matter how slowly you accelerate
the projectile.  You could correct for this with a circular accelerator
approach I guess, but I can't see this being small enough to fit in
a combat vehicle.

You might take a look at an earlier discussion about Kr'vak (sp?) 
railguns where it turns out the ship would be accelerated backwards
to the order of Km/S.

> That's also assuming you're using a mass driver with magnets. You can
also
> build a mass driver with two rails, a magnetic field, and a plasma
flow.
> Part of the projectile would be eaten up by producing the plasma
bridge.
> The result is even less recoil. I'm not sure this is feasible in a
tank
> based mass driver, though...

Doesn't matter how you accelerate the particle newton still applies.

Roger