Timeline for Weaponry made from extreme light-weight steel: swords and daggers
Current License: CC BY-SA 4.0
11 events
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| Jul 9, 2018 at 13:41 | comment | added | HonoredMule | Something else to consider is the weight of the swinging arm itself relative to that of the sword. That contributes inertia that does not translate to impact force, except to a limited but also mutually destructive degree. If the sword is not substantially heavier than your arm, then you are expending a majority of your force to no effect anyway. And how many times can you deliver impact force that is translated through your hand before that hand fails? | |
| Jul 7, 2018 at 8:56 | comment | added | Logan Pickup | @Delioth one style of swordfighting I've seen is to swing a sword as though you're throwing a punch. The sword begins behind your shoulder with your hand next to your shoulder, and at the end of the swing your arm and the sword extend straight out in front of you. If the sword is light enough to allow you to still extend your arm at 45mph, then the average speed of the sword at the tip is, with only an arm-length sword, twice that. If you delay the "snap" of the sword until later in the swing, the speed of the sword at the time of impact is higher. | |
| Jul 6, 2018 at 15:51 | comment | added | Delioth | Well... a punch is a straight line. The bat swing was measured at roughly the tip of the bat as far as I could tell. It's to get some context - if you can swing a 2 pound baseball bat at 80 mph, that's really close to the fastest you can swing any object regardless of weight. In any case, outside of the largest blades you aren't going to be able to move your arm fast enough to get extra energy into the strike - it'll be going a little faster but the reduced mass means it won't have nearly the same amount of energy. | |
| Jul 6, 2018 at 15:42 | comment | added | computercarguy | @Delioth, your research seems contradictory to me. You say a bat can be swung at 80mph, but then you also say that your arm can only go 45mph at it's fastest. Not only are these two different arm movements (punch vs swing), but they show very different results, so I don't know why you are comparing them to each other. As far as the bat vs sword, you don't say what the sword is, so a claymore swing is likely to be swung slower than a katana, which would probably be slower than a rapier for the same person or machine. Moment of inertia and weight have a huge factor here. | |
| Jul 6, 2018 at 15:31 | comment | added | computercarguy | @CodesInChaos, in college calculus and physics, I was taught that $F=1/2mv²$ is the derivative of $F=ma$, so changing $F$ to $E$ here would be more confusing. | |
| Jul 6, 2018 at 14:56 | comment | added | Delioth | Doing a little bit of research, some sources give me the record swinging a baseball bat (which is just under 2 pounds) at around 80 mph. Fastest sword swings clock at around 43 mph, though that may be at a different point on the lever compared to a bat. Either way, the fastest punch (and thus the fastest your arm can physically move) ever recorded was at 45 miles per hour... so we aren't getting anything close to triple the speed, even if our sword is perfectly weightless. @ArtificialSoul these blades are going to be less effective than a normal steel sword (at least for striking power) | |
| Jul 6, 2018 at 9:16 | comment | added | CodesInChaos | "$F=ma$" here $F$ is a force. But then you write "$F = \frac{1}{2}mv²$", where the right side is kinetic energy, so why are you reusing $F$ which is normally used to denote forces and not $E$ which is normally used for energy? This inconsistent use of variables makes your post pretty confusing. | |
| Jul 6, 2018 at 6:21 | comment | added | ArtificialSoul | @Delioth i agree. There are certainly martial arts that rely on extremely fast punches (e.g. Wing Tsun Kung Fu) but those punches are not comparable to the moves you make while swinging a sword. And they are not even 10 times as fast as a regular swing. | |
| Jul 5, 2018 at 21:42 | comment | added | Delioth | This answer appears to assume a human arm can actually swing anything 3-10x as fast as a traditional sword, which may not actually be the case. I'd like to see some source that shows a human arm can actually move that fast (because I'm pretty sure a person's arm can go maybe twice as fast tops with no load compared to swinging a standard sword). That's where the idea that you lose power with a lighter blade comes from - you can mathematically regain that force by increasing speed to compensate... but you can't physically gain that speed. | |
| Jul 5, 2018 at 15:46 | history | edited | ArtificialSoul | CC BY-SA 4.0 |
partially added math synteax for readability
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| Jul 5, 2018 at 15:37 | history | answered | computercarguy | CC BY-SA 4.0 |