Sliding weights

[Montino Bourbon]

actually the weight moving forward would make a longer pendulum, thus slowing it down, I think.

Besides, for the weight to have a real effect it would have to be big enough that it would add too much weight to make the sword useable.

[fearn]

Hi Montino,

You're right, but as I recall, the time of the pendulum works in part on the distance to the center of the pendulum's mass, not just its total length.

With a weight that slides for a long distance down the blade, you're right. The blade gets progressively more tip heavy, meaning that it will take more energy to move the tip and that it will hit harder (transferring more energy).

If the slide is short, around the blade's normal center of mass, what would happen is that the sword would go from back-weighted to front-weighted. Basically, this would mean that the sword accelerated a bit faster from rest (starting out back-weighted, as in a small sword), hit a bit harder (shifting to front-weighted), and was a bit harder to withdraw (still front-weighted). This type of design makes a lot of sense when you're only planning a single blow, as in an executioner's sword. In a battle, I'm not so sure that it's advantageous, but I don't know. We'll have to see what the engineers say.

One thing to remember is that a blade with a slot down the middle is probably more fragile than a solid blade of the same weight. Jens has proposed an interesting question, and it will be interesting to see some numbers around it.

Fearn

[Rivkin]

I truly believe that any sliding weight would be totally cool, fancy, and useless. I see no reasonable advantage over permanent placement of some weight at the sword's end, etc.

[Ian]

This topic is closely akin to the physics of hitting a baseball.

BTW, I notice that the on deck hitter often puts a ring weight around the bat barrel to take some practice swings, but does not try to emulate that weight in the bat itself. It slows down the bat speed and if the bat is overly heavy too much power would be lost -- kinetic energy is proportional to the square of velocity, but only linearly related to mass.

Ian

[ariel]

I remember years ago seeing a Chinese throwing knife that always hit the target with a point and got imbedded quite deeply. Apparantly the secret was a hole drilled within the entire blade along the whole length and filled with mercury. It moved freely in this channel and changed the center of gravity. Was very impressive.
I guess, the same principle as discussed here.

[Jens Nordlunde]

Montino, you may be right, we will hopefully know later, but I agree with you that a heavy weight getting stuck at the tip could be fatal.

Ariel, an interesting mail about the use of mercury in the blade, I can imagine that the result have been impressive.

Jens

[Mare Rosu]

Jens
You are at it again, from magnetic blades to now sliding weights.
Are you sure you moved to Switzerland and was not run off, to hide/escape?
Anyway the idea of sliding weights is a good one, while I have little to add to this subject I do think a distance related subject might be of interest to you and others and that is; Atlatls and banner stones used with them. I have found these banner stones in years past and this is just two web sites on their use. http://donsmaps.com/atlatl.html and http://www.primitive.org/atlstealth.htm.
To me a very interesting subject you have started Mr. Jens