# Would a telescoping sword be plausible?

I'd like to write about a character armed with a sword which telescopes, so that he can store it in an ordinary sheath but then draw it and extend it out to remarkable lengths.

Would this be plausible? If so, what are its limitations?

More specifically (re limitations), assuming it is possible, how long could such a sword be? What sort of material could it be made of? Would it have to be significantly structurally different from an ordinary sword?

Science-based answers only, please. Magic isn't part of this world.

• Your sword would (dependent on how much it extends) break very easily. As the extended part has to come from somewhere, the sword would probably be hollow when extended. So my guess is it is not really plausible. Will probably add a more complete answer later. – J_F_B_M Jan 1 '16 at 3:57
• Larry Niven's "Variable Sword" has the attributes you want, except it is made form SFNal technology (a stasis field) to stabilize a molecular filament that can cut through almost any other material. – Thucydides Jan 1 '16 at 4:29
• If you're willing to yield about the "ordinary sheath", it's possible to use the sheath as a reserve of material to extend the sword. Could be done by touching it with the pommel, or plugging it somehow. – meristel Jan 1 '16 at 8:05
• Nanomachines might be able to hold a structure and telescope like you want, but they may not have the structural integrity you want from a sword. If anything, you might want a spear that can extend on command, that'd be really useful. – Cort Ammon - Reinstate Monica Jan 1 '16 at 8:30
• "Telescoping" is the flip side of "collapsible," and who'd want a sword that collapses? – Michael Green Jan 1 '16 at 11:32

## 12 Answers

I'm pretty sure that it could be done today if engineers put their mind to it.

• Make a slender sword blade much like a rapier. Possibly with a core of tungsten or depleted uranium to make it heavy despite the thin blade.
• Make a tube to hold that blade, with springs and whatever.
• Add a cutting edge to that tube.

I wouldn't want to do more than two sections, or three at most. The second blade needs a good connection to the first blade, so the total will be less than twice as long as the sheath.

The sword would be much more fragile than a proper sword. The telescope mechanism might jam or come apart when the sword strikes a hard target. With medieval technology, "much more fragile" would be so fragile that the thing is useless as a weapon. With present day technology, "much more fragile" might still be useful as a sword.

• @nigel222, that's because swords are no longer serious weapons. I believe folks like Colt, H&K, or Raytheon would come up with much better swords if someone gave them a couple hundred million for R&D. – o.m. Jan 1 '16 at 11:39
• @nigel222 This is a false connection, for several reasons. 1. The finest Japanese knives use alloys not available even 75 years ago, and that's not saying anything about the extraordinary non-carbon-steel alloys coming out of the aerospace industry--also used in extremely high-end Japanese knives. 2. Much of what keeps the quality so high today is a business model predicated on extremely low overhead and small volume production. 3. The structural link between sword and knife technology in Japan is mostly advertising. – CAgrippa Jan 1 '16 at 14:34
• @nigel222 Japanese medieval blade making techniques were obsolete before they even started using them. Metal folding has appeared in every metalworking civilization: en.wikipedia.org/wiki/Pattern_welding in Europe it fell out of use by 10 or 11 century due to higher quality ores and advances in metallurgy. Compared to European weapons of the time, Katana is a short, heavy, clumsy and fragile weapon. Weight of 2 handed sword, length of one handed sword and designed to pierce wooden armour make it a very poor weapon compared to equivalents used in countries with real metallurgy. – M i ech Jan 1 '16 at 15:35
• @nigel222 - Japanese swords were exceptional - within their military framework of metal-poor combat. The prospect of a samurai making drawing-cut attacks on steel armor with a razor-sharp sword - well, I wouldn't want to bet on how long the sword will last. – WhatRoughBeast Jan 1 '16 at 21:59
• It should be noted that a telescoping blade runs the risk of collapsing every time you stab with it; rapier style swords are notoriously bad at cutting. Perhaps there is a better solution, but I do agree that it would be a pretty bad weapon compared to a non-collapsing weapon of the same style and type. – PipperChip Jan 4 '16 at 4:34

It's been a long time since this question was asked but perhaps the answer will help someone in the future.

I have a telescoping sword - the real deal, not a children's toy. (See advert for similar stuff) It was a gift from my wushu teacher some years ago as a practice sword since I don't need police permits to either keep it at home or cross international borders. It's also safe with my wonderful and hyperactive kids around (in case you are wondering). My telescopy is about 32 inches long, has about 3 sections and once closed in, fits into the hilt. The sections are made of metal and the hilt is plastic/polymer to keep the overall weight down.

For demonstrations and competitions, I usually borrow someone's 'proper' (read thin and non-telescoping) local sword for a couple of hours. East asian swords, both chinese and japanese, are prized for their thinness which gives them their incredible cutting and slicing ability. They usually require special folding and cooling techniques to make them strong because too thin=very brittle. A good double-edged Chinese straight sword is expected to be suitably springy, not too bendy, not too stiff. That is how a swordsperson would know that the sword is well made, thin but strong enough. The part closest to the hilt is the thickest with increasing thinness as you go towards the tip. A japanese katana, wakizashi or tachi has a single very-thin cutting edge with the other edge kept blunt and thicker for overall strength. Again, note the need to balance between thinness and strength.

A good swordperson knows his/her sword well and uses each part of the sword to his/her best advantage. There are specific moves tailored to the different parts of a sword including the hilt.

Chinese wushu double-edged straight sword rough drawing

My telescopy is incredibly blunt and has about 0 degrees of 'springiness', you could not possibly even cut soft pudding with it. I suppose if it was any heavier, it could be used as a bludgeon but would probably bend and break before it hurt anyone. Hence the very low people-safety-risk.

A viable sectional sword as a weapon would need special material and techniques to make, especially to keep it both thin and strong even with and at the joints. Consider that the interior would be hollow while it is extended, meaning greater weakness. Also it would not be 'springy' hence linear moves like jabbing and poking would be a bit difficult (You'd also have to keep oiling it and making sure the sectional sliding in and out is smooth, haha, I've had mine get stuck sometimes). We currently don't have the technology to make this but since not much research has gone into this (cultural swordsmakers are a rare breed in the modern age), perhaps if enough resources went into it, it could be possible. It would be pretty difficult to make though.

Remarkable lengths, not possible, sorry. Not only does it weaken the sword but also it makes it very difficult to wield. Normal 30-40 inches, possible. The first inner section can be used as a blunt bludgeon or blocker, the second middle section could be used as for smash-through hacking, the third for cutting and slicing the normal way. There could be special forms and routines to get swordspeople used to this.

I don't know much about western swords, my cultural heritage soup is limited to East Asian stuff, sorry. In case anyone is wondering, no, none of the people I know keep a proper sharp sword at home. Demos and competitions don't need sharpness and most of us are on the older side with young kids at home.

In Jennings "the Journeyer" there is a telescopic dagger described. The visible blade is split lengthways. In the hilt and core is a third spring-loaded blade. When a button in the hilt is pressed this blade is released and forced out between the visible blades to stab an enemy who thinks he has parried one's thrust.

Anyone know if this is fiction or a true description of a known historical weapon? Not exactly a sword but a spring-driven blade is better for stabbing than cutting in any case.

What about putting an edge and a hilt on one of these babies: Folding bike locks are designed to not break, so you are looking at something less flimsy than hollow telescoping swords. You could put in stoppers at each of the joints (I don't know what they're called, the ones where it locks into places and you push a button to release it) to lock each section at 180°. If this was well-oiled, a quick flick would fold each section out until it locked, leaving you with a nice sword that isn't hollow - the weak points are the joints/stoppers, so over-engineering them would be a good plan.

Edit: forgot to say: Yes it's going to be at an angle. Yes you have to deal with it. If your segments are thin, it shouldn't be too big a deal.

• A telescoping sword isn't the same as a folding sword. (Though oddly enough, I also have a question in mind about folding swords, which I might post here later.) – Rand al'Thor Mar 30 '17 at 15:09
• Hmm, I was thinking about this, but what would you say the parameters that define either are? And the question asks for it so that he can store it in an ordinary sheath but then draw it and extend it out to remarkable lengths. - surely the use is valid? – Hugh Nolan Mar 30 '17 at 15:11
• I'd say telescoping is when the extension of the blade is all happening along one axis, while folding is when there's motion in more than one dimension. And I'm not saying your answer is irrelevant; it's just not how I'd imagined the sword to work. – Rand al'Thor Mar 30 '17 at 15:17
• Good discrimination between the two - I could imagine a use case where a short telescoping sword is thrust and telescoped simultaneously, giving an attacker the element of surprise and an edge ;) over their opponent, which doesn't work with a folding sword, you'd need a slash to have the same effect. What is it that you were imagining someone doing with this telescoping sword? – Hugh Nolan Mar 30 '17 at 15:28
1. Viability: I admit that having an insanely long blade sounds cool, but think about the simple physics. If swinging, you have less leverage than your opponent from 12 feet away. For stabbing, the telescoping blade would simply collapse unless there is a reinforced locking mechanism.

2. it’s cool, so let’s do it anyway but do it right

Materials: Steel titanium alloy with bits of carbon nanotubes instead of the carbon typically used should give you incredible rigidity, and toughness combined ( if tempered properly).

Construction: I would recommend a blade in 2 or 3 sections and a sheath that can be pushed into the hilt, pushing what was the hilt to inside the mid of the blade, and functionally turning the sheath into the hilt. The idea being that the blade is no longer hollow, it is reinforced by the tube that had been the sheath. This would give you the rigidity to stab or hit another sword without the whole thing collapsing .

Such a thing kind of already exists.

Adapting this to a sword wouldn't be too hard. You would just need a safety latch to ensure it doesn't collapse on itself when you're trying to stab your enemy. In the toy lightsaber, it's made of several pieces, with the smaller end being slightly smaller than the next piece's larger end. Make this with a strong metal, like titanium, and it could make up for its brittleness.

Not quite sword and you have to give up on stabbing, but something based on baton style telescope[s] in the center and something resembling thin strained wire on the sides can be developed (with some experiments) into a decent foldable cutting weapon. Not the most resilient one however, you will have to be very careful using it and train to develop some unique skills (just like with authentic Japanese swords BTW).

On the bright side such weapon will be light, compact and quite likely turn to be most efficient if made without metal parts.

Well, considering the nature of what your sword does when drawn - why make the blade the telescopic part?
In any armed combat scenario "closing the gap" would be far more important than having a neat sword. Why not make the handle have a telescopic feature like the sections of a police baton activated by oh... I don't know... Pseudo-scientific gibberish?
The sword would then go from being a sword to a halberd of sorts. i.e: "Their swords locked with no hope of your hero closing the gap due to the size of the opponents blade. Your hero cleverly goads an attack from their enemy and at that moment places their hand on the pommel of their sword activating the hidden function. The sword extends to its full length leaping off the hero's palm and through their target."

It seems like a fairly common idea, as I am also doing that idea. It is, but I'm going to talk about the mechanism. For my story, the tip and sheath have magnets in them, so the sword unfolds as it is pulled out. There are also several snap locks in each segment that are disabled by a small bump in the sheath. The metal is extremely sturdy and lightweight, in this case an alloy of titanium, carbon, iron and a fictional metal. The blade would also be hollow.

I don’t know why this question has resurfaced, but if anyone is still curious I’d recommend a chain weapon instead of a telescoping sword. Making the sword telescope undermines a lot of its best characteristics, completely throwing off balance, stability, and making it much more likely to break. Why not turn those into advantages?

The ninjas figured this out a long time ago, with the kyoketsu-shoge. It’s a hook-like blade on the end of 10-20 feet of chain or rope, and is used almost exactly like you’d expect. It has a ring on the other end which could be used for defense and to hold onto the weapon.

In this way, you pick up all the obvious advantages of a telescoping sword without needing to worry about the drawbacks. Experts with the tool were even supposedly able to pull a sword from an opponent’s hand with it. It doesn’t look as cool or feel as dramatic, I admit, but nobody will be laughing when they’ve got a hooked blade in their throat.

All the answer where about spring or collapsing system.

Is talking about shape memory metals out of subject ?

What about some metal that is shaped like a small broad sword, but when submit to an electrical current will morph to a long thin rapier ?
I think that with our current understanding of shape memory metals, it's too much 'magic'. It will work as a toy or as a technological wonder, but will be inefficient as a weapon.
But with a little suspension of disbelief, it should work.

• Please don't make your answer look like a request for clarifications. – Mołot Oct 27 '17 at 14:03

Looking at a collapsible baton, it's not a bad starting point for making an collapsible sword. it wouldn't be hard to attach a short knife blade to a collapsible baton, giving the reach of a sword with only a little bit more space than a collapsible baton. the weapon would not have an edge along it's entire length, but many sword fighting techniques advocate using the last 3 to 4 inches of the sword to strike with good force at an ideal distance. the end result would be more like a mix between a sword and a short spear, but this would be the cheapest easiest way to get something close to the original goal of the question.