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Lance K.
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 Posted: Wed 28 Jun, 2006 8:38 pm Post subject: What is CoG? |
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I did not see this listed in the glossary, and could not find a definition with search.
I saw it referenced in the specs for the Viceroy:
CoG: 4.75" (12 cm)
Thanks
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Gabriel Lebec
myArmoury Team
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| Posted: Wed 28 Jun, 2006 8:46 pm Post subject: |
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Center of Gravity (or, more rigorously, center of mass). Distinct from center of percussion (CoP). CoG is often measured from the crossguard towards the point.
Last edited by Gabriel Lebec on Wed 28 Jun, 2006 8:48 pm; edited 1 time in total
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Jean Thibodeau
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| Posted: Wed 28 Jun, 2006 8:47 pm Post subject: Re: What is CoG? |
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| Lance K. wrote: | I did not see this listed in the glossary, and could not find a definition with search.
Thanks |
I think it means Centre of Gravity. Or: http://www.abc.se/~pa/mar/cog.htm Depends on context and Google gave me a lot of strange alternate meanings. 
O.K. couldn't resist to tease a little, no harm meant. 
You can easily give up your freedom. You have to fight hard to get it back!
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Lance K.
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| Posted: Wed 28 Jun, 2006 8:52 pm Post subject: |
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So in reference to my other post about the Viceroy, is CoG that same as PoB?
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Gabriel Lebec
myArmoury Team
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| Posted: Wed 28 Jun, 2006 8:53 pm Post subject: |
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Hi again; I just posted in that topic referring you back here. 
Yes. CoG is a bit more technically precise than PoB, since people occasionally mean different things by "balance."
-GLL
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Lance K.
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| Posted: Wed 28 Jun, 2006 9:00 pm Post subject: |
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Got it. Thanks!
Lance
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Jean Thibodeau
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| Posted: Wed 28 Jun, 2006 9:06 pm Post subject: |
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| Gabriel Lebec wrote: | Hi again; I just posted in that topic referring you back here.
Yes. CoG is a bit more technically precise than PoB, since people occasionally mean different things by "balance."
-GLL |
Cog is a very 3 dimensional thing while with point of balance one could speak of how far from the guard the sword would balance on a finger.
With a strait symmetrical blade the two are the same for all practical purposes but with a very highly curved blade the CoG might actually be floating in the air above the top of the blade in a sabre or below the blade with a Kukri or yatagan blade.
Think of a Donut: the CoG is actually at the very middle where the hole is.
The PoB might be 5" from the guard but with a asymmetrical blade the CoG could also be 5" from the guard but at the top of the blade or floating above it in on one of the other 3 dimensions: One can feel this in the handling of a very curved blade when one tilts the blade from side to side.
( Well, I could be wrong, and for all practical purposes they are the same. )
You can easily give up your freedom. You have to fight hard to get it back!
Last edited by Jean Thibodeau on Wed 28 Jun, 2006 9:31 pm; edited 1 time in total
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Nathan Robinson
myArmoury Admin
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Jean Thibodeau
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| Posted: Wed 28 Jun, 2006 9:41 pm Post subject: |
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Interesting and maybe I was reaching too much for distinctions between the two, but with a curved blade the Cog won't be on the center line and would affect handling, I think, in the way I imagine.
Actually I haven't read here anything that I remember about the handling of curved blades : I have an original very heavily curved Shamshir and when the blade is on the side it feels very different than a strait blade when the hand and sword are turned to the side: The strait blade feeling neutral while the curved blade wants to twist out of your hand.
Just curiosity. 
You can easily give up your freedom. You have to fight hard to get it back!
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Vincent Le Chevalier
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| Posted: Thu 29 Jun, 2006 6:09 am Post subject: |
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Jean,
You are right, with a very curved blade the fact that the center of gravity is not in line with the handle can make the weapon feel different, even in static handling. However, since the handle is not necessarily in line with the forte of the blade, I suspect that there are curved blades that do not have this effect, if the center of balance is aligned with the handle it will not tend to twist it when turned to the side. That could be a reason for hilts curving opposite to the blade in a number of curved swords...
I've seen a iaito (training Japanese sword) that had a small defect: the handle was not contained in the plane of the blade, thus the COG was often not right behind the edge when stopping a cutting motion, and that resulted in an unpleasant twist in the hands. Slight, but still disturbing. So I think you are right pointing out that the center of gravity is really a point in space, and not just a distance from the guard...
Since most European swords are straight, the 3D nature is most of the time hidden and we can safely speak of the point of balance as 1D. Plus, the 3D position is something not easy to find out, it would involve 3 measures with the sword hanging from 3 different points. Since the 1D distance from the guard is already quite significant, I believe looking just at that makes sense.
Or we could go at the intermediate level and say it's 2D (distance from the guard + distance from the handle's axis for example) but I'm quite confident someone will still find some exotic weapon where that's not enough 
Regards
--
Vincent
Ensis Sub Caelo
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This is a standard topic