From: Will England[SMTP:email@example.com]
Sent: Thursday, July 23, 1998 11:45 AM
To: Michael Prestage; Nathan Morton
Cc: England, Will
Subject: why a gatling gun wont work in space
"Z-80 system stack overflow. Shut 'er down Scotty, the system's sucking
mud" - Error message on TRS 80 Model-16B
---------- Forwarded message ----------
Date: Tue, 21 Jul 1998 21:08:08 GMT
From: Randall Joiner
Berry Kercheval wrote:
>(Randall Joiner) writes:
>> A. Things at such temperatures begin to react badly.
>> B. Every action has an equal and opposite reaction, and with both
>> rotational and linear forces being applied to said gun, you could have
>> a problem.
>> C. Gas and elements freezing to barrel, barrel swings back into
>> place, bullet fires, bad things happen to barrel/gun/spacecraft.
>> D. Standard Lubricants don't in space.
>> E. Standard shells don't fire in space
>Most of those things seem to say that a Vulcan (GAU-8, right?) would
>fire *poorly* in space, and might, of not assembled and lubed with
>space-qualed lubricants, fire for long, but it would fire for a few
>minutes after being hauled out of the airlock.
Poorly in reference to not practical. A couple of shots coming back
at you, or causing the weapon to explode, in a vacuum, could do some
Truly Bad(tm) things.
Long is also a relative term with a weapon that fires that many
shells, in that amount of time.
>It might not be practical, it might not be a good idea, but it could
>work. Sort of like Windows.
Ah, but Windows has a tendency to not work at all, and often doesn't
work when most needed... Truly Bad(tm) thing.
>Most of those are simple engineering problems, anyway; there's nothing
>that says you can't solve them. BEsides, pushing a lead slug slightly
>too large down a steel tube generates heat; I doubt that after the
>first couple of rounds through a given barrel there would be any
>problem with condensation. The combustion gases mught condense on the
>SPACECRAFT, now that could be a problem.
Simple and space are never put together in an engineering stand point.
True, they could be solved. But why? What point would a
Gatling/Vulcan/rotary gun solve in space, that other things wouldn't
Yes, the slug generates heat in the barrel. Let's look at a little
bit about space... Radiation of heat energy... _VERY_ difficult in a
space enviroment. Yes, it's cold in space. and given enough time, a
non-heated object will become very cold. But heat doesn't transfer
quickly in a partial vacuum (I _refuse_ to get into that discussion
again) due to the lack of molecules. One hydrogen atom in a couple of
cubic feet does not lead to quick loss of heat energy for a solid or
liquid. A gas will quickly lose heat in the vacuum of space due to
the loss of pressure and gain in volume. (Ideal Gas law)
So, we have several solid barrels, spinning, each firing a shot as a
barrel comes into contact with the trigger and firing hole (I beleive
that's still the design of rotary barrel weaponry). The shot is
fired, the gas expands _rapidly_ losing thermal energy, and quickly
reaching or exceeding the point where the gas turns to a solid. If
you're lucky, the gas will expel itself entirely out of the barrel
before this, but if you've ever cleaned a gun hear on earth after
shooting, you know that some residue is always left... Compound it
with space's quick freeze.
Next, you have a "hot" barrel, that can't cool itself (one of the
reasons for rotating and using multiple barrels), so quickly as more
shots are fired through it, begins to at least warp, if not completely
break down. This happens much quicker than it would on earth, giving
a possible 1-2 seconds before a misfire or backfire occurs. The
heated barrels, trigger and fire hole, could also cause a general
ammunition explosion, as while the barrels can't radiate heat into
space, they can do so down the structural pieces and the ammo feeds
(unless they're thermo resistant, but that's not the case today)
Given that the general principle of aim for these weapons is shoot
many many shells at said target, and try and get some to hit... You
have a weapon that is not effective if it breaks down before it can
pump out enough shells. If the 10th shell causes a breakdown, or the
100th, and you're used to shooting 10000, then you're odds aren't all
that good of being effective with it.
Then there's the fact that you've got all sorts of interesting
problems to deal with... Vibrations, both in firing, and from
launch/travel. I don't think that those weapons were really meant to
handle 7-10 G's of force, vibrations of that length of time and that
magnitude of force. Then there's the fact that the ammo, while
waiting to be shot, would freeze. Heard what happens when things
reach such temperatures? IIRC the explosives used in standard ammo
will not ignite or burn in near zero KELVIN temperatures. Again, the
ideal gas law comes into affect... Pressure is a _direct_ result of
the volume and temperature of the gas... And normal ammunition is
used to being ignited in temperatures roughly 250 degrees above what
space is. (0 Kelvin= -273 C, IIRC)
Then there's the fact that on the earth, the tolerences for ammo do
not have to be that great. So long as the powder/charge burns quick
enough, and there's enough mass in the way, and there's only small
"holes" to allow gas to escape, there will be enough pressure behind
the shell to shoot it out the barrel... I garuntee you that a
riffled[sp?] barrel does not have a perfect pressure seal, nor does a
break barrel shotgun, or any other weapon... And when you combine
this with the extreme pressure differences between earth and space,
you could get some _very_ unpredictable firing, if it fires at all.
Now, let's look at a gravity less feed system... HOW do you propose
to get thousands of rounds per min into a weapon? Gravity?
unpredictable. Spring? With that many shells, and a belt fed system?
I don't think so. Gas pressure? See above. Mechanical? Mechanics
notriously don't work well in extreme temperatures.
>And I don't know why you think standard shell wouldn't fire in space.
>As already noted, lack of oxygen is not a problem since the charge in
>the shell contains it's own oxidizer. Why WOULDN'T a shell fire in
>space? THe main aspects of space are cold, vacuum and microgravity,
>none of which should make gunpowder not work.
Cold: You're lucky if you can get the lubricant to allow the gun to
spin. Standard ammo will not ignite in cold measured in 2 digit
Kelven. Gas will not expand nearly as quickly in that temperature,
nor will it necessarily expand in the same manner as on earth. If you
do get the gun to fire, you'll be lucky to not find you've burned the
thing up, or get a back-fire. Given several shots, you'll be lucky it
doesn't blow the ammo or your spacecraft up.
Vacuum: I refuse, absolutely refuse  to argue this subject much
more than to say that things do NOT operate like normal in it, and it
gives one HELL of an interesting twist to physics, engineering, and
Microgravity: Ammo feed problems. Aim problems. Not much else would
gravity effect in this arguement.
> by gunpowder I mean "propellant charge in the shell", not
> necessarily a charcoal/saltpetre/sulfur mixture
Understood to mean standard propellent used in ammo of today's day
 Due to an extremely bad and distasteful run in with luser on
Alt.folklore.science and a discussion with said luser on the topic of
Vacuums, I refuse to argue/discuss said topic without the use of my
[-1] And I do mean USE the 9mil.[-2]
[-2] Final solution?
[ seti@home -- Shooting -- Motorcycle -- Blog ]
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