Spudguns in space

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
User avatar
Ragnarok
Captain
Captain
Posts: 5401
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK

Sun Nov 22, 2009 6:17 pm

jackssmirkingrevenge wrote:Would it really need that much rocket power?
If you could stop it, relative to the Earth, it would drop purely from gravity. Bear in mind, at the ISS' orbit, gravity is still 90% of what it is on earth. It's only because anything in orbit is in free fall* that things appear weightless.

(*And only because of its sideways velocity does that freefall cause it to miss the earth - same basic principle as escape velocity, differentiated only by altitude)

Stop it orbiting, and without that "centrifugal force", it'd drop. Although it must be noted, the ISS does 7.7 km/s. That's quite a lot of "stopping it orbiting".
How about one huge fin then, could also serve as a shield, with a visor cut out :)
Consider where that heat is being radiated TO. You've got your soldier behind a large flat fin that's trying to lose 10 kW of heat in his direction - not good.

In practical terms, the best option is to create a firearm that'll survive high temperatures, and which uses the aforementioned water cooling (hey, it's what NASA uses for spacesuits).

Alternatively, just be prepared to deal with very short barrel lives.

Either way, as combat in a vacuum is not going to happen in the near future (and to be frank, would probably be short lived, given the fact that a mere glancing hit on a vacuum suit would prove fatal to the user), the matter is not of particular importance.
Does that thing kinda look like a big cat to you?
User avatar
D_Hall
Staff Sergeant 5
Staff Sergeant 5
United States of America
Posts: 1924
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Has thanked: 8 times
Been thanked: 44 times

Donating Members

Mon Nov 23, 2009 12:49 am

jackssmirkingrevenge wrote: Why's that, considering the point of the Navy's current railgun development is a pure kinetic weapon. The concept of "smart spears" - guided metal rods without explosive - dropped from high altitude bombers has also been floated around, at least by those at the Skunk Works:
two words: nuclear weapons

say the Russians detect a massive launch of ICBMs We're just launching kinetic rounds against some hard targets in Iran. How do you convince the Russians that it isn't a nuke strike against them?

That, my friend, is a very dangerous game to play.

One that isn't much of a problem for rail guns or bombers.
Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Nov 23, 2009 5:57 am

D_Hall wrote:two words: nuclear weapons
That's three words according to Dennis Leary:D

Fair point, though really you can fit a nuclear warhead to pretty much anything these days.
Alternatively, just be prepared to deal with very short barrel lives
You wouldn't need rifling though really, with no air resistance. Unless I've missed something, an unrifled projectile should show no tendency to tumble end over end, and of course fins would be useless.
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
POLAND_SPUD
Captain
Captain
Posts: 5402
Joined: Sat Oct 13, 2007 4:43 pm
Been thanked: 1 time

Mon Nov 23, 2009 6:54 am

You wouldn't need rifling though really, with no air resistance
lol that's a fair point

also becasue there is no air resistance the guns wouldn't have to be as powerful
Children are the future

unless we stop them now
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Nov 23, 2009 7:01 am

POLAND_SPUD wrote:also becasue there is no air resistance the guns wouldn't have to be as powerful
tsk tsk, that kind of thinking will keep you off any US consulting body on space warfare. Silly efficienct mad Europeans! MOAR POWER!!!!!!!

:D :D :D
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
Ragnarok
Captain
Captain
Posts: 5401
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK

Mon Nov 23, 2009 8:28 am

jackssmirkingrevenge wrote:You wouldn't need rifling though really, with no air resistance. Unless I've missed something, an unrifled projectile should show no tendency to tumble end over end, and of course fins would be useless.
Yes, a fair enough point, but the discussion was about using terrestrial firearms in space. The point was originally sparked by Firefly - I'm sure fans will recognise the episode (D_Hall particularly so).

So really, the design was looking for something that could work both in or out of vacuum (perhaps in a similar way to how the Russian ASM-DT can be used on land or in water).

And rifling or not, a barrel still needs to maintain physical integrity.

So really, the design was looking for something that could work both in or out of vacuum.
Does that thing kinda look like a big cat to you?
User avatar
D_Hall
Staff Sergeant 5
Staff Sergeant 5
United States of America
Posts: 1924
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Has thanked: 8 times
Been thanked: 44 times

Donating Members

Mon Nov 23, 2009 8:50 am

jackssmirkingrevenge wrote: Fair point, though really you can fit a nuclear warhead to pretty much anything these days.
only if you are interested in treaty violations.
Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Nov 23, 2009 10:53 am

Ragnarok wrote:So really, the design was looking for something that could work both in or out of vacuum (perhaps in a similar way to how the Russian ASM-DT can be used on land or in water).
Now that you mention it, the ASM-DT sounds like the perfect space weapon :)
only if you are interested in treaty violations.
Or do your design work somewhere within the Axis of Evil ;)
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
CpTn_lAw
Corporal 5
Corporal 5
Posts: 987
Joined: Sun Sep 11, 2005 9:10 am
Location: France

Mon Nov 23, 2009 3:13 pm

Good ol' BP cannon :D And you get a free trip in the opposite direction :P
"J'mets mes pieds où j'veux, et c'est souvent dans la gueule."
User avatar
jimmy101
Sergeant Major 2
Sergeant Major 2
United States of America
Posts: 3206
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Has thanked: 6 times
Been thanked: 18 times
Contact:

Mon Nov 23, 2009 3:51 pm

Didn't a recent firefight in Afghanistan have problems with melting barrels of M16s?

If a real combat firefight can melt the barrel in air then in space the same firing scenario would make the barrel a molten pool after a lot fewer rounds were fired.

In addition, the breach would probably fail pretty early on. No cool air being circulated with each cartridge.

Further further more, a cartridge might not fit in the breech. What's the coefficient of thermal expansion for brass versus steel? Would the cartridge be too big or too small when the cartridge and the gun are at -200C or at +130C?

A year or so ago there was a blurb in PopSci about firing a rifle on the moon. Amazingly (or not depending on your point of view :) ) the academic they got to answer the querstion got things wrong. Like the affect of recoil. Recoil on the moon would be basically identical to that on earth. Indeed, it would probably be less noticable to the shooter since the shooter would be ~100 pounds more massive on the moon due to his spacesuit.
Image
User avatar
D_Hall
Staff Sergeant 5
Staff Sergeant 5
United States of America
Posts: 1924
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Has thanked: 8 times
Been thanked: 44 times

Donating Members

Mon Nov 23, 2009 5:37 pm

jackssmirkingrevenge wrote:Or do your design work somewhere within the Axis of Evil ;)
Except that they're signatories to the same treaties (well, I guess that depends upon your definition of "Axis of Evil.").
Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Nov 23, 2009 7:45 pm

jimmy101 wrote:Didn't a recent firefight in Afghanistan have problems with melting barrels of M16s?
Unfounded, apparently.
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
Brian the brain
Moderator
Moderator
Netherlands
Posts: 3497
Joined: Mon Dec 05, 2005 2:06 am
Location: Holland
Been thanked: 7 times

Tue Nov 24, 2009 1:20 pm

Ermmm....

How about just using a diver's speargun?
No airresistance means unlimited range so....


That would solve all pressure issues.

( yes a crossbow too, but that's unwieldy)
Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
User avatar
psycix
Sergeant Major 4
Sergeant Major 4
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands

Donating Members

Tue Nov 24, 2009 2:40 pm

Mechanical seems like a very good way to store energy in space. Independent of the atmosphere, not generating a lot of heat.

On top of that, mechanical launch systems can be charged by electrical motors, for which the energy comes from solar panels (or nuclear).
Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

Spudfiles steam group, join!
User avatar
jimmy101
Sergeant Major 2
Sergeant Major 2
United States of America
Posts: 3206
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Has thanked: 6 times
Been thanked: 18 times
Contact:

Tue Nov 24, 2009 3:39 pm

jackssmirkingrevenge wrote:
jimmy101 wrote:Didn't a recent firefight in Afghanistan have problems with melting barrels of M16s?
Unfounded, apparently.
Really?
Despite the military's insistence that they do, a small but vocal number of troops in Afghanistan and Iraq has complained that the standard-issue M4 rifles need too much maintenance and jam at the worst possible times.

A week ago, eight U.S. troops were killed at a base near Kamdesh, a town near Wanat. There's no immediate evidence of weapons failures at Kamdesh, but the circumstances were eerily similar to the Wanat battle: insurgents stormed an isolated stronghold manned by American forces stretched thin by the demands of war.

Army Col. Wayne Shanks, a military spokesman in Afghanistan, said a review of the battle at Kamdesh is under way. "It is too early to make any assumptions regarding what did or didn't work correctly," he said.
I would say it is unclear if there was a problem or not.

It must be said though that the M16 (and it derivatives) has had it's detractors since it was first used in Vietnam more than 40 years ago.
Image
Post Reply