Re: Rail Guns don't recoil

Oh No wrote:
Thus spake Neil B. <neil_delver@xxxxxxxxxxxxxxx>
Also of course, statements about momentum being directed out to the
sides don't solve anything - the conservation law is a vector identity!
It seems to me the rail magnets, in near proximity to the projectile,
should have nearly complete reaction forces right against them instead
of needing to appeal to equipment below.

I am sure this is right.

So this empirical result (correct I suppose?) is still perplexing.

The original statement confused different ideas. The comment was that
the rails do not need anywhere near the strength of material required to
control the kickback of an explosive weapon. But that is natural. In
rough terms, the peak force applied in an impulse is inversely
proportional to the duration over which the impulse is applied. I should
think there is a difference in duration for applying the accelerating
force, or impulse, of two orders of magnitude or more compared to an
explosive weapon. That means there can be just as much reaction
momentum, but it might require less than one percent of the force to
control it, hence one percent of the strength of material.

This cannot be true.
A projectile launched by gas pressure is accelerating all the way down the tube. This is also the case with a railgun projectile. For the same length and same final momentum the forces are going to be approximately the same, spread over the same duration.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
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