Do coilguns/railgins have recoil?

I think they do, but I can't find any info on whether they do or not.

Edit: Thanks then, and I knew about the equal/opposite thing, but I had the tiniest possible inkling that the force was acted upon the barrel/rails instead. Looking back on it, that was probably stupid.

edited 6th Apr '11 3:07:13 PM by Ekuran

Of course they do.

http://www.utexas.edu/research/cem/IEEE/PR%2052%20Weldon%20Publications.pdf

"We learn from history that we do not learn from history."

Equal and opposite reaction stuff.

Think about what it would mean if they didn't have recoil.

^ EDIT: Oooh, my brain hurts after reading that.

edited 6th Apr '11 2:40:03 PM by pvtnum11

Happiness is zero-gee with a sinus cold.

I've been thinking of a set of stories that take place in a universe where mankind has settled hundreds of planets. There's huge space battles. I was trying to think of a way for space ships to shoot at each other without using explosives (which need oxygen) but still having sufficient missile speed. So I thought giving space ships rail guns would be a good solution. If the missiles are big enough, you could shoot at targets on a planet's surface. (The missiles need to be big so that they'll do enough damage even when part of them will be lost when they enter the atmosphere). The missiles that are to be used against other space ships don't have to be that big, because penetrating the target is plenty of damage without anything more necessarily needed.

You think this is too unpractical?

Quod gratis asseritur, gratis negatur.

It's perfectly practical. In fact, it's super-effective. Depending on the scale involved, a smaller faster projectile will be orders of magnitude more effective than a large one.

edited 6th Apr '11 2:54:41 PM by Yej

Da Rules excuse all the inaccuracy in the world. Listen to them, not me.

I had an aborted ring-raiders story in which missiles and railguns were the two common weapons. Missiles blew up in proximity to a target, and the resulting shrapnel is what did the damage, although there were simple kinetic impactor missiles.

Provided you have enough ship mass and a recoil-absorbing mounting on the gun, the recoil need not be that big of a deal.

Could also make it a spinal mount, so that recoil force is directed throgh the center of mass of the ship, or something, so all you do is shed a bit of velocity, and you dont' even impart a roll or yaw to the ship when you fire, due to the torque the firing would induce, if it wasn't an axially-mounted gun.

Counter-firing some opposing thrusters would also serve to reduce or eliminate vector changes on the ship as a whole.

Writer's Block?

Happiness is zero-gee with a sinus cold.

Writer's Block, as in, the thread? Nah, I'm not gonna write it anyway. I'm too lazy to write anything, plus the story's really stupid if you're not me. (Most of the characters and events are reflections of changes in my life, so they probably wouldn't mean anything or be entertaining for anyone else. The only reason anyone would read it is that I like to shove in references to as many things as possible without forcing them in, so I'll have at least one reference to another work or a famous speech in every page.)

But that's enough about my story; this is OTC.

Quod gratis asseritur, gratis negatur.

Bummers. Sounded promising.

Happiness is zero-gee with a sinus cold.

Except the gunpowder in cartridges is also sealed off from air and those work fine.

Missiles still work in space.

They just don't do any splash damage.

My other signature is a Gundam.

@Best Of

Actually, explosives do not need oxygen (or air) to work: one of the reason why they are explosive are because they carry their own oxidiser (like oxygen atom), so that they can react fast enough to make a boom.

edited 6th Apr '11 3:27:19 PM by renovalino

Monopropellants, same story there. And yeah, sealed rounds would still work, although cleaning the gun bore while it's in vacuum would be a sucky EVA job. To eliminate that, rail/coil guns would be ideal.

Happiness is zero-gee with a sinus cold.

Every weapon you don't specifically design to be recoilless has recoil. Those you DO design to be recoilless have less "punch", so it's typically only rocket launchers and grenade launchers got no recoil.

Also, a recoilless mechanism can hardly be recoil-operated semi-auto, which kinda sucks.

edited 6th Apr '11 3:39:20 PM by SavageHeathen

You exist because we allow it and you will end because we demand it.

Recoilless weapons require a counter-force to balance out the force of the moving projectile. For most recoilless weapons, this involves blasting the combustion gases out the back of the weapon, hence the tube shape and the similarity to rocket launchers in appearance. The backblast from these weapons is very powerful and will kill you if you stand behind one or fire one with your back to a wall.

edited 6th Apr '11 3:39:05 PM by WoolieWool

Out of Context Theater: Mike K "'Bloody Pussies' cracked me up"

The recoiless part is a bit of a misnomer, too - it recoils in both directions, cancelling it out so the shooter feels no recoil force. With an RPG or rocket, you either have lots of gas being blown back, or throw-away plastic bits blown backwards to act as counter-mass. In both cases, the backblast area is dangerous. That danger will persist in space, so you have to factor in where the backblast may go so you don't end up scorching/trashing delicate widgets you may have on the hull of your ship. Although since gas will dissipate quickly, I'd bet that a recoiless weapon system in space will be of the excess gas type, and not the plastic trash type, for use as the counter-mass.

^ Ninja'd...

edited 6th Apr '11 3:41:57 PM by pvtnum11

Happiness is zero-gee with a sinus cold.

There'd be no reason not to fire self-propelled missiles from a pod with an exhaust clear of the ship or to eject the missiles before ignition.

Either a weapon has recoil, is self propelled, or is based in Artificial Gravity. Or I suppose it could be all of the above.

Fight smart, not fair.

I suppose Artificial Gravity here includes other planet-related shenanigans, such as an hypothetical "recoilless railgun" that would twist the Earth's magnetic field or something.

Of course, once we have this kind of thing, we can make any gun seemingly recoilless by welding an Immovable Rod equivalent to it (not a "truly immovable rod", mind you).

"And as long as a sack of shit is not a good thing to be, chivalry will never die."

For the record, coilguns only work as space-to-space weaponry at absurdly tiny (relatively speaking) ranges. Say, for example, that a ship in low Earth orbit is firing at a ship in lunar orbit. That's about 400,000 km. It takes a space ship three days to go that far. It takes light more than a second to travel that distance (~1.3 light-seconds). Even if your coilgun can fire a projectile at 400 km/s (which is huge — the US Navy has tested railguns that are absurdly powerful and only fire at 2.5 km/s), it'll still take more than 15 minutes to reach its target at that range; plenty of time to see it coming and get out of the way.

Really from Jupiter, but not an alien.

Which is why you use a nuclear warhead with bomb pumped x-ray lasers. Can't get out of the way of those.

Can you really see it coming if it's small enough? How big does the projectile have to be to cause significant damage?

edited 7th Apr '11 8:32:57 AM by Medinoc

"And as long as a sack of shit is not a good thing to be, chivalry will never die."

Not if it's a black cube 1/2m^3 to a side. No Stealth In Space only applies to manned objects.

Not very. Damage depends on mass and velocity, not so much volume.

(Personally, I prefer the microscopic tungsten widget fired out of a particle accelerator at a large portion of c.)

edited 7th Apr '11 8:33:31 AM by Yej

Da Rules excuse all the inaccuracy in the world. Listen to them, not me.

@Jovian: Or worse, intercept it. Two kinetic energy rounds slapping into each other results in a net nullification/disintegration of both.

Basically they hit a bullet with another bullet and shattered both.

You have to be moving at relativistic speeds (something not likely attainable via technology for quite some time) to close the firing window to just within seconds for the so-called idea that because Space Is Big you have to engage at distances measured in AU or light-time. Know what I'm saying?

Missiles are the same way. A guided missile running on ion drive at 60km/s is going to take forever to hit anything at distances greater than say 30,000 km. When things take forever to hit you, you have ample opportunity to utilize your anti-projectile defenses or simply get out of the way.

@Bomb-pumped lasers: Science Has Marched On. The Beam Spam by such weapons popular in the Honor Harrington verse are more or less impossible on known physics.

edited 7th Apr '11 8:34:46 AM by MajorTom

"Allah may guide their bullets, but Jesus helps those who aim down the sights."

O rly?

I trust you can give me the sauce on that SMO. 'cuz I can't think of any reason it wouldn't be effective.