Re: Gauss weapon (and other) recoil

I apologise for the delay.  I have finally located my source of Traveller
military knowledge: Book 4, Mercenary.

Mark F. Cook [email removed] writes:
> In TML Subject 1761, Bertil Jonell ([email removed]> writes:
> >   The gaussrifle fires a small 4mm calibre bullet. This bullet travels at
> > 1000m/s which is about as fast as an normal 5.56 NATO round. And yet, the
> > gaussrifle inflict 4D with a penetration of 7, while a 5.56 NATO in Traveller
> > would inflict 3D at around 3 or 4 in penetration.
> >   This would indicate that the bullet from a gaussrifle travels much faster
> > than a normal rifle bullet, maybe somewhere in the range of 1500 to 2000 m/s.
>
> In fact, the Imperial Encyclopedia does list the velocity as 1500 m/s.

And so does Mercenary.  Incredible as it may seem, GDW have actually kept
something consistent! :-)

> >   How this weapon can be thought as being particularly recoilless is beyond
> > me:)
>
> MT does NOT list gauss weapons as being "recoilless".  They list them as
> being "low recoil", which is appropriate.  If you consider both F=ma and
> Newton's 3rd Law ("Equal and opposite reaction") then the amount of enery
> delivered to each gauss needle (and thus acceleration, since the needle's
> mass is constant) is equal to the amount of recoil energy delivered to
> the gauss weapon firing the needle.

Time for some number crunching.  First, a correction to the above.  It's
momentum, not energy, that Newton's 3rd law deals with.  Figures for Traveller
assault rifle and gauss rifle come from Book 4; figures for M-16 assault rifle
come from "The Armory" by Kevin Dockery, in brackets in the assault rifle part
for comparison.

	Mass of a fully loaded assault rifle = 3.33 kg	   (3.635 kg)
	Mass of a 6mm slug from assault rifle = 0.005 kg   (0.00365 kg)
	Velocity of slug = 900 m/s			   (999.7 m/s)
=>	Momentum of slug = 4.5 kg m/s			   (3.65 m/s)
By Newton's 3rd law, momentum of rifle = 4.5 kg m/s in the other direction.
=>	Velocity of rifle = 1.35 m/s			   (1.0 m/s)

	Mass of a fully loaded gauss rifle = 3.90 kg
	Mass of a 4mm needle from gauss rifle = 0.004 kg
	Velocity of needle = 1500 m/s
=>	Momentum of slug = 6 kg m/s
=>	Momentum of gauss rifle = 6 kg m/s the other way
=>	Velocity of rifle = 1.54 m/s
=>	A gauss rifle is no more a low recoil weapon than an assault rifle.

The gauss rifle gets its extra penetration from the small calibre plus the
greater impact; it gets its extra damage from the higher kinetic energy.
How it gets a low recoil is beyond me.  Maybe it incorporates a reactionless
drive. :-)

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 Adrian Hurt			     |	JANET:  [email removed]
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