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Post by Deleted on Jun 6, 2007 20:55:37 GMT
Tsafa, I disagree, there are several designs that can do everything. The type XIX comes to mind (talk to adam on this) but the XVI and XII were quite adept at versatility. These swords thrust and cut remarkably, rivaling the type XI in cutting prowess and the XV in thursting penetration. Yes, I think that type XV and XVI come close a good effective medium between cutting and thrusting. But you will have to put a more power into the type XV to make the same cut you would make with a type X. The tip of the XV tends to kick up on impact as a result of less mass at the tip. Type XVI would kick up less because it has more mass at the tip but point control would be harder in thrusting. It is not that any of these swords can not perform either task, but rather that you must put less effort into doing one task vs the other. This is within the scope of what I said that cutters should be more flat/wide and thrusters thick/pointy. Making a flat/pointy blade is going to yield a useless blade that folds as has been demonstrated.
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Post by Deleted on Jun 7, 2007 19:02:58 GMT
What do you mean 'kick up'?
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Post by Deleted on Jun 7, 2007 19:25:08 GMT
If the tip does not have enough mass often I find it will bounce of a wood 2x4 dispite being sharp. It still leaves a cut behind. A heavier blade does not have that bounce effect so all the force goes into the target. It goes deeper into the wood and often stops dead. I discribe it as "kicking up" because that it was is seems like. I can make a tappered blade not kick up by striking harder, but that goes back to issue striking harder with less or more force to achieve the same results.
The kicking up is a seperate issue then if the lighter blade had hit the target and stopped dead with less of cut into the wood. The kicking up suggests that not all of the force is transfered into the target, but that some is transfered back. What ever the reason, I don't like my blade bouncing back.
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Post by rammstein on Jun 7, 2007 19:26:49 GMT
I'll get to testing that right now, give me 2 seconds
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Post by rammstein on Jun 7, 2007 19:31:00 GMT
Alright results with shrewsbury against the witham (VERY noticable point of balance issues, but I don;t know what they are...maybe 2 1/2 and 4 inches respectively? and the witham is far shorter):
The shots throw with the point as cuts were very much as tsafa says, they tend to fly off a little. Not much, but they most certainly do. However, I was lucky enough to see something wrong with this test: Cuts are not thrown with the tip, they are thrown with the center of percussion, about 2/3 up the swords blade. When tested like this, both swords hit the target cleanly with no vibration and no deflection.
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Post by Deleted on Jun 7, 2007 19:31:39 GMT
I think the size of pommol may reduce that effect too. I have one tapered sword with a large heavy pommol that does not do this. When I discribed this to someone a while ago in another forum, they explained that the pommol has having a lighting rod effect and aborbes some of the reaction force from the target. This may or may not be true, I don't know.
Good point about the point of percussion issue. My tests where both near the tip. But it seems to still stand that a tip strike with a thrusting sword is less effective. This points back to the original point that I brought up that some swords do somethings better (or more effortlessly) then others.
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Post by rammstein on Jun 7, 2007 19:34:20 GMT
The pommel serves to balance the sword. The heavier the pommel, the farther back the point of balance is. Obviously the Shrewsbury's pommel is heavy, otherwise it's PoB wouldn't be so close to the hilt, no? So it's hard to have a sharply tapering thrusting sword without a decent pommel.
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Post by Deleted on Jun 7, 2007 19:37:30 GMT
Yes. I agree, but perhaps I has the secondary benefit metioned too. Not sure.
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Post by rammstein on Jun 7, 2007 19:40:40 GMT
I still wouldn't discount some of the more transitional swords in the oakeshott typologies. I'd be willing to bet that a type XIX wouldn't fare so poorly against a type X. And we all know it can thrust better. However, I'd have doubts that it could thurst as well as an XV. Still, it can thrust moderatly well and cut extremely well. What about the type XVII? This sword had blade mass and could cut exceptionally well because of its hexagonal x-section, yet it could thrust very well too because a hexagonal x-section allowed both for cutting and thrusting ability. Plus the sword has large profile taper meaning it's an ever stronger thruster.
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Post by Deleted on Jun 7, 2007 21:50:27 GMT
If you don't think cuts are thrown with the tip, then I'm sorry to say that you're wrong. Center of Percussion has less vibration this is true. But if I'm fighting you, in a duel, or on the battlefield, and I'm trying to cut you with the final 2-3 inches of my sword and you're trying to cleave me with your center of percussion, then dare I say you're at an INCREDIBLE disadvantage. Swords were the length they were for a reason.
A WELL balanced sword(read: Albion, Atrim, or Tinker) will exhibit far different handling and cutting dynamic than a Gen2, even when they have similar PoB and overall weight. This is not a question of center of gravity or center of percussion at all. It's completely independant of those factors.
Whenever you strike an object with a lever(a sword) held at one end, the velocity of the whole sword changes, but not by the same amount at every point on the sword. Different parts of the sword will exhibit different amounts of change of velocity. Obviously, the point of impact will be most effected.
There is another point on the sword call a 'dynamic pivot point' that exhibits NO change in velocity when an impact is made elsewhere on the lever. This dynamic pivot point is not an absolute spot on the sword like CoG or CoP, but rather for any given point of impact, there is a corresponding Pivot Point.
What does this have to do with swords? you may well ask. Well, let's see.
When you hit something with a sword with the intent to cut, it usually has a lot of momentum behind it. According to Newton, and, subsequetly, Physics, for every action there is an equal and opposite reaction. I.E. the harder you hit something, the harder it hits back. This can be measured, and with most of our swords it is felt in the hands and wrists.
If you hit something with your sword and you feel the hilt kick backwards into your palms, it's because the dynamic pivot point corresponding to the impact point of the sword that you just hit is below where your hands are. If you feel it kick forward into your fingers, it's because the dynamic pivot point is above where your hands are. If you feel no kick into your hands, it's because the Dynamic Pivot Point corresponding to the point of impact is right where your hand(s) is(are).
obviously, since this is a dynamic thing we're testing, hitting the sword at different points along the blade will correspondingly change where and if we feel this kick in our hands. Since this is something we want to minimize(it ranges from uncomfortable to painful and isn't good for the bones or joints in any case), it'd be a good idea to design the sword, using careful distribution of mass such that given an impact point at the preferable cutting spot on a sword, the dynamic pivot point would be as near the hands as possible. It is possible to test this in any given sword.
Such an individual DID test a number of historical originals, and he found that in ALL of them, impact points at or very near the point of the sword produced corresponding dynamic pivot points very near the hands, which minimized(in some cases, completely) the kick felt in the hands. This can be and was tested objectively, as there are ways(involving pendulum motion) to very exactly measure this phenominon.
What does this tell us? Given the number of swords tested, it's hard to believe that this was coincidence. Particularly when many modern replicas were also tested, and in the replicas the dynamic pivot points were all over the place for a tip impact point, and the preferable impact point for a well placed dynamic pivot point was anywhere from halfway down the blade, to the theoretical point 3 feet beyond the tip of the sword!
So we've got replicas behaving in non predictable manner, and originals all behaving similarly in this regard...
Anyway, think about it. Given rotational momentum the tip of the sword is moving at the highest velocity, and gives you the most range. Sure it's not AS beefy as a spot more down the blade, but when you consider that with good form, the effective mass of the sword is added to by the wielders own mass and inertia(and in many cases, more than that, as good grounding will literally add mass from the earth itself into the cut) the extra fractions of an ounce of actual blade mean very little.
As for the 'bounce' you describe when cutting into woodblocks, that's from either bad form or a poorly designed sword(from a dynamic balance point of view). We develop that all the time in Aikido. We have an in-dojo tire pell set up. A good strike with a bokken or sword will not only sound very much different from a bad one, but it won't bounce off despite the fact that the tire is rubber.
Sorry about that rant... I'll get my sources for this info shortly.
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Post by rammstein on Jun 7, 2007 21:57:00 GMT
Sorry adam, I didn't make myself clear. Of course cuts can be thrown with the tip. It adds a nice reach advantage. My point was to show that the PoB was the area that is meant to be cut with, or is preferable, but not necessary. After reading my post again, I realize I came off sounding a little stupid, and of course your right adam however, depending on what armour we're in...I think I'd take hitting you with the CoP if we're in some type of protection, but the tip if we are unarmoured.
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Post by Deleted on Jun 7, 2007 22:05:09 GMT
You're absolutely right, against some heavy armor, tactics change drastically.
However, I think MOST people actually on a historical battlefield didn't have too much plate armor.
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Post by rammstein on Jun 7, 2007 22:06:38 GMT
Of course not, however I wouldn't be so quick to discount a padded jack and boiled leather. It's deceptively hard to get through that.
Anyway long overdue karma point from me for that indepth analysis.
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Post by ShooterMike on Jun 7, 2007 22:18:30 GMT
Adam, I have to award a karma point for that detailed analysis too. I knew a little from reading Tinker's treatise on harmonic vibration. And now I see how points of rotation play into the picture too. Many thanks.
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Post by rammstein on Jun 7, 2007 22:19:49 GMT
You know, I had to put yet ANOTHER nick into my shrewsbury to say what adam put for better than I ever could of ;D
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Post by Deleted on Jun 8, 2007 0:57:38 GMT
I think there is an ARMA article somewhere that describes what we are talking about. I read it a long time ago. What Adam said sounds familiar. One of the things I remember is that they had two rods, one with a pommol and one without. They showed in the illustration, the pommoled rod not bouncing on impact because of the pommol, where the rod without the pommol bounced.
Also, I think some swords intentionally focus on somethings rather then others. I just did a quick test with one of my Rapiers which is almost exclusively dedicated to thrusting and in cutting it bounces a lot. You can't say that is is due to bad design, because it is balanced near the hilt and performs its task of thrusting very well and has great point control. If you modify it so it has less of a bounce, like a cut and thrust, you will sacrifice ease of point control.
I have come to form the opinion that when it comes to balance, weight, length, mass distribution, it is more of a question of what you prefer for your fighting style rather then absolutes of this is poorly balance vs what is well balanced.
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Post by Deleted on Jun 8, 2007 1:41:07 GMT
Very true, Tsafa. All humans being unique, who in their right mind can say "This sword is balanced perfectly for everyone."? No one. We all have our tastes.
And yes, Tsafa. There is an article about that on ARMA. I found it recently and actually emailed tinker about it as it conflicts somewhat with his article on 'harmonic balance'. We sorted it all out in the end.
That being said, back in my freshman year of highschool I did a whole report on the rotational dynamics of swords... I just couldn't cite myself about it all. Which is why Adam became a happy panda when he found that ARMA article.
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Post by ShooterMike on Jun 8, 2007 1:52:32 GMT
...I have come to form the opinion that when it comes to balance, weight, length, mass distribution, it is more of a question of what you prefer for your fighting style rather then absolutes of this is poorly balance vs what is well balanced. I completely agree with this. In comparing the handling of some high-end swords that are based on historic examples, their handling is all over the board. I have an Albion 1st Gen Crecy that is designed as a Type XIIIa Grete Schwert of War. It is very point heavy and doesn't balance close to the guard at all, something like 6-7 inches. But for fighting with two hands, in maille armor, it would seem to be devastating. The other is an Albion Regent Type XVIIIa that is just about identical in length and weight, but is TOTALLY different. It is obviously intended as a THRUST-and-cut sword. Not that it doesn't cut well, but definitely not with the same sheer power as the Crecy. However, its point control is almost rapier-like and the blade is 2 inches wide. These definitely two top-line swords and they illustrate Tsafa's point well. They each do well and handle supremely for their intended purpose, but would each be relatively ineffective if used for each other's style of fighting.
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