Stay with me here... energy rifle-sword made scientifically feasible

Question

I've decided I want a sword which in addition to being fully functional as a sword, can also fire energy ( or some other ammunition which can be produced when needed as opposed to being carried around) at enemies.

About the specs: -It is essentially a longsword with internal machinery, regular sword handle and all

-It should preferably be able to fire a continuous beam as well as individual bolts

-Preferably no openings in the sword that lead to the inner machinery

-Assume sufficiently advanced materials to account for the sword remaining durable, UNLESS you have a more realistic idea what it could be made of

-The actual nanotech of the sword should build on some existing scientific principle

-Energy supply may or may not be internal, although I'm leaning towards it being external

Given these criteria, how do I build this monstrosity of a weapon?

EDIT: Changed plasma cannon to energy rifle as it's a broader term for the kind for "ammo" I'm looking for, clarified a few things

See Are gunswords feasible? for why combining ranged weapons with melee weapons is generally considered a bad idea — Anketam, Feb 07 '17 at 01:38
The first thing to do is to imagine a reason why a plasma cannon would be an effective weapon... — AlexP, Feb 07 '17 at 02:47
Similar to D'argo's qualta blade in farscape? http://farscape.wikia.com/wiki/Qualta_Blade — EveryBitHelps, Feb 07 '17 at 06:51
Anketam, it won't have the same issue with ammo, structural weakness, and the handle is for sword use — ArborianSerpent, Feb 07 '17 at 07:25
Spencer because I don't want a bayonet, it must work as a regular sword — ArborianSerpent, Feb 07 '17 at 07:26
EveryBitHelps No the blade doesn't deform to make it a rifle, all of the propulsion is made from inside the sword while the projectiles are outside it or travel through the metal of the blade to the outside, no holes — ArborianSerpent, Feb 07 '17 at 07:28
@Spencer bayonet is used on a rifle as a last resort solution. You shouldn't need it, ever. And it turns your weapon into short spear, not sword. Today it is rarely used. — Mołot, Feb 07 '17 at 07:33
EMP gun that is enclosed in blade? The best idea I think as your aiming with this would be close to none so you would need a vide area of impact. — SZCZERZO KŁY, Feb 07 '17 at 12:20
@Mołot Perhaps, but ArborianSerpent should edit the question and add their own reasons fir this. — Spencer, Feb 07 '17 at 13:37
@Spencer I replied to your comment, the simple reason is that it isn't supposed to be a bayonet, because a sword would be cooler — ArborianSerpent, Feb 07 '17 at 15:22
Is there poison too? Not on the energy, of course; just the sword. Although poison energy might be cool. — Willk, Feb 07 '17 at 19:06

score 3 · Answer 1 · answered Feb 07 '17 at 12:57

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Gonna go low-tech here:

Rather than using one blade, your sword could have two parallel blades that would act as the rails of a railgun. The hilt of the sword would house the firing mechanism, necessary electronics and the ammunition for a few shots. Power could come from a portable power pack (batteries, capacitors...) attached to the hilt with a power cord.

This seems the most feasible with current technology, albeit not necessarily very effective. And unfortunately can't fire beams of energy as you specified in your question.

For a stream of energy, the best I can propose would be basically a flamethrower with a sword attached. Another solution would be a laser.

The problem we face isn't really the form-factor of the weapon (sword rather than a gun) but the energy/ammunition requirements. To keep with the idea of the weapon, your best bet is to have something with batteries in the hilt.

answered Feb 07 '17 at 12:57

Subbies

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I just googled plasma railgun and it's apparently a thing, I like this idea the most, and I could tweak the ammunition with need – ArborianSerpent Feb 07 '17 at 15:15
Yes, if I recall correctly, the ammo used to create plasma balls for rail guns are thin sheets of conductive metal, so they get quickly ionized and heat up to become a plasma due to their high surface/volume ratio. – Subbies Feb 07 '17 at 16:10
You could also ionize gases (and thus create a plasma). Keep the gases in a container with your batteries and feed the gas through the hilt like for the batteries. This, coupled with a fan (or maybe the electric current is enough, I'm not sure) could allow for a constant stream of plasma being fired. – Subbies Feb 07 '17 at 16:22
That would make really bad sword. Either you have each blade half as thick and thus twice as fragile, or you would have it too heavy for normal use. – Mołot Feb 08 '17 at 10:06
@Molot It will make a bad sword, but not for the reasons you specified. With all the added weight and internal mechanics, as well as the power cord, the sword will be more unwieldly than a regular sword. However blade thickness is a non issue since it will depend on the materials used as well as the blades profile. Look at historic swords from longswords to rapiers and the difference in their blade size and thickness. – Subbies Feb 08 '17 at 10:32
@Subbies I did. And I was practicing both Chinese and European Historic Sword Fighting. Not a lot, but enough to see that material will only help to some (not that large) extent. Oh, and I make my own blades, too, so I think I know what I'm talking about. High alloy steel is best you can get, and it allows only maybe 10, 20% of weight reduction. Not even close to 50% when you have to keep the same elasticity, chipping resistance and edge retention. – Mołot Feb 08 '17 at 10:37
@Molot qhat about using carbon fibers or even nanotubes? Maybe create a crystalline structure to support whatever – dot_Sp0T Feb 08 '17 at 23:01
@dot_Sp0T carbon fiber and nanotubes are elastic. hard to break by pulling, but very, very easy to bend. Great for whip, but can you use whip as a sword? For crystalline structure, best one we found so far is.... steel. – Mołot Feb 08 '17 at 23:04
@Molot the best accessible materials we have are steels, but considering the op contains the word nanotech, I think we can assume more advanced materials. Graphene foam is extremely strong but probably to stiff. Combine it with an HEA like CrMnFeCoNi though and you could get a very sturdy blade. – Myrdden Wyllt Feb 09 '17 at 00:42
Some tweaks that may help a bit: Sword mode: The twin blades interlock to form a single blade. Should be sturdier than 2 thinner blades. The hilt is in line with the blade. Rifle mode: Blades separate for rail, hilt angle adjusted to rifle grip style. An additional grip on the bottom blade allows for holding the sword like a gun. A retractable Power/ammunition cable leading to a waist/back mounted pack is attached to the hilt magnetically. – Lu22 Feb 09 '17 at 06:19

Turksarama · Answer 2 · 2017-02-07T04:26:57.917

Easiest solution is that the sword 'blade' itself is actually a plasma stream. That way, in order to make it fire a plasma bolt, it can simply fire a vortex out of the same opening the plasma comes from which should hold it together for a short while, while a beam simply involves ramping up the blade power (though without the vortex range would be shorter).

You may want to hand wave some powerful magnetic confinement, or else have a sheath that is kept inflated by the plasma pressure (this partially alleviates the heat problem, and makes your sword more solid).

Some things to consider if you're worried about realism: how is the sword powered, and more importantly, how does the wielder deal with the intense heat?

I'd say that's a lightsaber, I'm thinking something with a metallic blade — ArborianSerpent, Feb 07 '17 at 07:31

score 2 · Answer 3 · answered Feb 08 '17 at 22:45

Ignoring all the usual stuff about "gun-blades", how aiming a sword like a gun is terrible, and how trying to use a sword with a handle designed for aiming guns would be equally terrible, you could conceivably do this with mechanisms built into the handle.

Have the quillions (the cross-guard end bits) generate powerful electromagnetic fields parallel to the blade. Perhaps augment them with a high-current coil wrapped around the base of the blade, and you should be able to fling magnetic/electrically charged ammunition along the blade. Think "Star Wars bowcaster" with a blade protruding from the front, but hilted like a sword. Similar to the rail-gun idea but without using a dual-bladed sword.

As an aside, cranking up the power could ionize the air around the the sword, creating a corona discharge, which would pretty effectively turn your sword into a sort of lightsaber (via plasma sheath) while also very quickly embrittling the blade. Might make for a good last-ditch attack.

score 0 · Answer 4 · answered Feb 07 '17 at 10:50

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how about this; your sword is a normal blade with an inner coil witch creates a magnetic field. The end of the hilt or the pommel is a small fusion reactor witch 1) powers the coil for the magnetic field. and 2) Produces plasma (witch envelops the blade and is held in place by the magnetic field). a violent swing could 'trow' plasma at the opponents (I myself doubt the scientific accuracy of this). I will give some thought to your individual bolts since I have no answer to that yet.

the blade would be made of ceramics not iron since it is more heat resistant.

answered Feb 07 '17 at 10:50

PDek

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Doesn't seem like a ceramic blade would be sufficiently hard to actually use in battle – ArborianSerpent Feb 07 '17 at 15:22
@ArborianSerpent Maybe use a tungsten based alloy instead? You could also mess with the magnetic field to launch the plasma. – DomineSatanas Feb 07 '17 at 16:30

Stay with me here... energy rifle-sword made scientifically feasible

4 Answers4