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Chad Arnow
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PostPosted: Tue 31 Jul, 2007 6:20 pm    Post subject:         Reply with quote

Angus Trim wrote:

And that's only what's already been written....... there's a lot more to share, just going to have to get the right conversation going.


Yeah, it's one of those "over a beer" conversations. Who's buying? Happy

Happy

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Vincent Le Chevalier




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PostPosted: Wed 01 Aug, 2007 1:35 am    Post subject:         Reply with quote

Jean,

I'm nearly sure that what you describe is an effect of pivot points, perhaps mixed with the node of vibration when you try it with a sword. I have experienced the same kind of effects as well.

There are three main reasons I think it has to do with pivots:

- You describe a dynamic feeling (i.e. the weapon must be moving)
- You feel it on very stiff objects like a mace or waster
- You are not hitting so hard that vibrations can get significant

If I understand what you say, the feeling is also sharper on forward balanced object like a mace. It can be explained: the concentration of mass in the head tends to keep the pivot points close together, so that all the pivots associated to all the points of your hand are pretty much in the same place, and you feel it quickly if you stray from this spot.

I have also the impression, from the way you describe it, that when you hit in this test, the motion of the weapon is a rotation around a point very near your hand. This has the further effect that the point of impact where the most energy is dissipated coincides with the point where the least shock is felt in your hand. The effect is possibly all the more obvious.

There is one way to be sure of the role of pivot points: try it with a simple stick, changing the position where you hold it. If it's what I think, here is what should happen:

- When you hold the stick very near the butt, your "sweet spot" should be one third of the stick's length down the tip
- When you hold the stick at one third from the butt, the "sweet spot" should move and be located near the tip

Of course there are all the cases in between. This moving sweet spot cannot be caused by the harmonics, as the location of the first node as we measure it does not depend on the location of you hand (and is hard to find on a stick anyway, except by the sound it makes)

If the point you describe is indeed what I think it is, you should also be able to locate it without even striking something, just moving the weapon with the eyes closed, paying attention to where on the blade you feel the mass. It takes a bit of getting used to, but after 4 years studying pivot points it's now obvious in my hand Happy

On a final note I'd be wary of saying what's "the best part of a sword to cut with". In my opinion, the best part of the sword is primarily determined by the tactical context, next by the target, next by the motion you can make with the sword, and only lastly by considerations of shock or vibrations in the hand. All this means that the best part moves all along the blade during a fight... Thus, in the end all the points we measure are only an indication, a way to predict how the sword will behave, but not a hard and fast rule "this is where you should hit".

Best,

--
Vincent
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Jean Thibodeau




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PostPosted: Wed 01 Aug, 2007 5:42 am    Post subject:         Reply with quote

Vincent Le Chevalier wrote:
Jean,

On a final note I'd be wary of saying what's "the best part of a sword to cut with". In my opinion, the best part of the sword is primarily determined by the tactical context, next by the target, next by the motion you can make with the sword, and only lastly by considerations of shock or vibrations in the hand. All this means that the best part moves all along the blade during a fight... Thus, in the end all the points we measure are only an indication, a way to predict how the sword will behave, but not a hard and fast rule "this is where you should hit".

Best,


Thanks for the whole reply. ( deleted some of it just to avoid the reader having to re-read the whole thing again and cluttering up the post: This gets really bad when people use entire strings of quotes over and over again. Wink )

Oh, I agree with the idea that there is no best place to cut with " tactically " : Tip cuts can be very effective and a cut with the forte could be the fist point of contact of a long draw cut or just unavoidable if one gets too close in a fight and has to use this part of the blade to at least block, which it does well being the forte and is used all the time in parrying if not for cutting.

As to the rest of your post I think I understand what you mean in general if not in detail.

Oh, if one hold a sword vertically and one moves the hand rapidly for side to side in a wiggle/waggle sort of way one can see, at least in the vertical direction, a point of rotation somewhere mid blade that doesn't seem to move or want to move and this seems to be at or very close to the sweet point. Holding the sword vertical probably takes the PoB out of the equation or at least minimizes its effect on the order variables that I don't quite understand as well as the easy to find PoB.

With a longhandled sword this point is affected I think to a degree if one holds one handed near the pommel or near the guard.

Oh, the tests, with a wooden waster or even just a wooden dowel and even more with a sword, needs not be very violent to get the different feel caused by hitting with different parts of the blade and also doing the same but varying the position of the hand up or down the object used. ( Obviously with a sword this is always the handle but with a staff-like object or pole arm hand(s) position can vary widely and has an affect on what feels " right/sweethspot " and what feels like wasted energy or unpleasant vibrations.

I guess all this for me is not based on math or study, but on decades of just casual play with swords or swordlike objects and focussing on the feel in the hand(s): A bit like trying to explain a taste with words when one doesn't have the vocabulary for it. One know the difference and can say basic thing like salty, sugary, sour, tart and maybe a combination of these but how does one explain in precise words the difference between salmon or tuna sushi. Eek! Laughing Out Loud

The sensory approach can work I think if one explain what to do, gives an idea what to look for or feel and if this test is valid, it's easy for someone to do it with any sword but it's not something one could give a formula for that would be useful unless someone first found all the relevant values of mass distribution, flexibility etc ...... Probably something it would take a super computer to calculate while a little wiggle/waggle would give you the answer faster. Wink Razz Laughing Out Loud

Oh, the test can be the striking test and/or the wiggle/waggle one.

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Randall Pleasant




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PostPosted: Wed 01 Aug, 2007 8:07 am    Post subject: Re: PoP Calculation         Reply with quote

Gianluca

You might want to read Sword Motions and Impacts: An Investigation and Analysis by ARMA Senior Researcher George Turner. The article is something of a long read but it is very enlightening. If you are into reading numbers George also has a longer version that includes his supporting data.

http://www.thearma.org/spotlight/GTA/motions_and_impacts.htm

Ran Pleasant
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