# Thread: Cloud Buster Sword question - hilt snap and other questions

1. ## Cloud Buster Sword question - hilt snap and other questions

https://www.youtube.com/watch?v=X6QSu1EolCI <-- This video talks about how impractical it is. Let's set those parts aside.

I had to wonder, if it were roughly made of steel it would weigh ballpark about 250 lbs according to what I plugged into this: http://www.custompartnet.com/quick-t...ght-calculator. I used .291 as the density of steel, 1 inch as the width, 12 inches as the length, and 72 inches for the height. This is a simplification since it's assuming just a slab of steel. However, I feel like the hilt would snap if you tried to swing it at 40 mph (as described in the video, and the description of the video is of a sword that had an aluminum core).

How much force would the hilt have to withstand? What material could handle that much force? Would it have to be made of proto-adamantium or would some lesser material suffice? Also, those two materia slot holes probably aren't a good idea?

So many questions... (link to OOtS 223)

2. ## Re: Cloud Buster Sword question - hilt snap and other questions

I think the critical information we're missing here is how long it takes for the sword to get up to 40mph on the swing--it can't possibly do that instantaneously, because that would require infinite force and any material would break. You also need to calculate the moment of inertia of the sword, because the weight alone doesn't tell you how hard it is to swing--as an example, if all of the 250lb were in the hilt (clearly it's not, this is just a thought experiment) then it will be a lot easier to swing than if the 250lb is all concentrated in the tip of the blade. It's been a long time since I did any of that stuff, though, so I'm not sure where to get started!

3. ## Re: Cloud Buster Sword question - hilt snap and other questions

Wasn't it forged on man at arms?

4. ## Re: Cloud Buster Sword question - hilt snap and other questions

Originally Posted by HolyDraconus
Wasn't it forged on man at arms?
Yes, but with an aluminum core. So that one weighed about 80 lbs or something. The description in ff7 is fully steel I think.

5. ## Re: Cloud Buster Sword question - hilt snap and other questions

Originally Posted by factotum
I think the critical information we're missing here is how long it takes for the sword to get up to 40mph on the swing--it can't possibly do that instantaneously, because that would require infinite force and any material would break.
Nothing can ever happen "instantaneously", but it might be easier all around to look at the problem at the other end of the swing: what happens when the sword, going at 40 mph 65 km/h, hits something and comes to a complete stop? Someone that remembers all the appropriate formulas should be able to calculate the amount of force exerted by the swing, and that force will be transmitted to the hilt and the arm (btw, the human arm is a fairly decent shock absorber - that's why it's probably impossible to snap a sword with a sword strike).

GW

6. ## Re: Cloud Buster Sword question - hilt snap and other questions

I was thinking it might be easiest to just calculate how much force you'd need to accelerate the blade to 40mph over a distance of, say, one-third of a circle, since that's probably about how much a swing is? You'd still need the moment of inertia of the blade to get that, though, even ignoring air resistance and suchlike, and that's the bit I'm really not sure how to calculate.

7. ## Re: Cloud Buster Sword question - hilt snap and other questions

The Monster Hunter games have a set of similarly ludicrously big swords, and a generally believable set of physical motions to go along with it. Perhaps we could use those as a starting point for the speeds and timing involved?

8. ## Re: Cloud Buster Sword question - hilt snap and other questions

Some extremely crude (and probably wrong) napkin math gives around a ~900 MPa strength requirement for a ~2 inch circular cross section hilt at a basic(!) swing. That's more than twice the strength of, say, S355 grade steel.

Still, it's in the same order of magnitude, so theoretically with a thicker hilt, stronger material, and a sharper edge (a cleaner cut would reduce the forces on the sword), it's possible to not break the hilt with a swing.

The real issue is the weight and balance point of the sword, I'd think.

9. ## Re: Cloud Buster Sword question - hilt snap and other questions

bigger question is how the heck tiffa manages to survive the nukie with cloud when bastard casually swing 100 kg sword at 65 km per hour. talk about special bread super soldier. there is no chance in burning heavens that common human can operate at that parameters. so only explanation that cloud ( if he is genue human) handling that is there is some sort of gravity materia embedded in some where in his body.

10. ## Re: Cloud Buster Sword question - hilt snap and other questions

Originally Posted by Grey_Wolf_c
that's why it's probably impossible to snap a sword with a sword strike).
Oh, Hilt Snaps are possible. About 10 years ago I struck a sword against a rotten tree stump. The blade remained stuck in the stump but the sword was broken at the hilt.
It was a low-quality sword and we had used it before that final strike quite often against other swords. We were lucky that the sword finally broke as it was swung against a tree instead of another sword wielded by a human.

11. ## Re: Cloud Buster Sword question - hilt snap and other questions

As bonus: Here is a video of a man making that sword with steel and such. It is heavy. You don't swing that; you lift it up and drop it on something.
(He also has one of Squall's gunblade. Similarly heavy.)

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