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Benjamin H. Abbott
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 Posted: Fri 18 Sep, 2015 10:32 pm Post subject: |
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Draw weights matter both from a basic physical perspective and according to numerous historical sources. Countless texts from periods where bows played an important military role valorize drawing a strong bow. You see this across time and space. Unlike in China and to a lesser extent in the Middle East, as far as I know Europeans never specifically measured draw weights. Regardless, European texts from the era of the warbow note the importance of strength for archers. Of course other factors matter too, but all things being equal it's better to have a heavier bow and historical warriors knew this.
We started talking about flight arrows because I brought up Sir John Smythe's claim that circa-1600 English archers could shoot 400-480 yards with flight arrows. I thought this implied quite strong bows, but based on recent flight records with English-style bows it's possible it was done with bows under 150lbs and high-quality flight arrows.
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Will S
Location: Bournemouth, UK Joined: 25 Nov 2013
Posts: 164
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| Posted: Sat 19 Sep, 2015 1:27 am Post subject: |
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The strength of archers is very different to the strength of bows. You could theoretically take 10 identical bows (in poundage, profile, tiller shape, timber, mass and cast) and give them to 10 different archers. It would always be the stronger ARCHER who shoots further.
In my opinion, its this understanding of bows and the shooting of them that is more important than simply looking at a table of data on the EWBS flight records and basing research on it. It's meaningless when discussing armour penetration or performance of a particular bow.
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Timo Nieminen
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| Posted: Sat 19 Sep, 2015 3:14 pm Post subject: |
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If all 10 archers can draw the bows to full draw, why would there be a difference?
If only one of the archers has the strength and technique to reach full draw, then that archer should shoot furthest. This would suggest that the bows were not chosen well. An archer who can just draw a 100lb bow will shoot better with a 100lb bow than with a 150lb bow that doesn't reach full draw.
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Will S
Location: Bournemouth, UK Joined: 25 Nov 2013
Posts: 164
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| Posted: Sat 19 Sep, 2015 3:21 pm Post subject: |
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Because the strongest archer will be far more comfortable at full draw, even if each archer can get to full draw. Just being able to reach say 32" isnt being in control of a bow - that comes when full draw is easy and form and technique of the loose can be perfected, not just form and technique of the draw itself.
This is why somebody like Joe will almost always get a better distance out of somebody else's bow than they will. It's also why many bowyers (myself included) give him a new bow to shoot because he will always get the full potential from it, even if the owner of the bow can also get it to full draw. It's both demoralising and inspiring to witness.
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Timo Nieminen
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| Posted: Sat 19 Sep, 2015 9:31 pm Post subject: |
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If it's a matter of form and technique (loose and otherwise), then skill matters, not just strength. Enough strength to be able to use that technique with the bow in question is a pre-requisite, of course. (By measuring strength in terms of draw weight of the bow that can be brought to full draw is already including technique.)
Given 3 archers, two with poor technique, who can just draw 100lb and 200lb bows, and an excellent archer who can just draw a 150lb bow, who will shoot a 100lb bow best? The strongest archer, or the archer with the best technique.
Technique matters. In particular, poor technique will hurt performance. Insufficient strength for the bow will hurt technique. But strength alone will not extract more energy from a bow, at a given draw length (it can reduce the energy, even, by allowing the archer to more comfortably hold the bow longer at full draw, which will increase energy loss through hysteresis).
Given sufficient strength and technique/skill, how large do you think the improvement in terms of delivered energy might be if the archer had more strength and more skill? Large enough to range/penetration tests meaningless, or a small enough improvement so that it's lost in the noise?
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Will S
Location: Bournemouth, UK Joined: 25 Nov 2013
Posts: 164
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| Posted: Sun 20 Sep, 2015 2:47 am Post subject: |
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Well this is where it gets difficult. The questions you're asking however are exactly the questions that need to be asked - just assuming draw weight equals result is why I think the original post is so far wide of any useful information.
However (and this is purely my opinion based on watching people like Joe shoot) I would say in your first scenario the archer who can shoot 150lb would perform best with the 100lb bow. The archer who can just shoot 100lb is out of the equation as he will be struggling to reach full draw therefore no focus is placed on technique of loose. The archer who can shoot 200lb may have pure brute strength and be able to heave back the weight, but may have poor loose technique still. The archer shooting 150lb has "excellent" technique and has a clean, powerful loose. The 100lb weight isnt near his limit so no strain is getting in the way of form and he can focus purely on a smooth, fluid rolling loose.
Mark Stretton has spoken in some detail about the difference between an archer who can DRAW 140lb and the archer who can SHOOT 140lb. There is a vast difference.
There is a guy here in the UK who can draw (just about) 170lb bows. There is very little doubt however that given a straight distance competition between himself and Joe, Joe would beat his distance by a large margin. He is so much more comfortable at that weight that his form and technique are able to be utilised, unlike the guy who is using all of his might to get back to 32" and letting it go in a great release of strain with a clumsy, aggressive loose and bad timing.
If you personally could just about shoot 120lb for instance, and were competing for distance using a 90lb bow against somebody who could just draw 100lb (also using a 90lb bow) you would win.
Whether this has an impact on penetration of armour I couldn't say, but I would imagine a fluid, clean loose would make a difference?
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Benjamin H. Abbott
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| Posted: Sun 20 Sep, 2015 9:53 am Post subject: |
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Certainly it's important for archers to master their bows rather than struggle with them. Assuming most of the archers on Mary Rose were shooting 150-160lbs bows as the estimates go, that presumably means they could skillfully shoot these weapons while at sea. The various officer exams in the Chinese region that required pulling heavy bows likewise often (not always) required the people tested to shoot such heavy bows accurately and repeatedly. For example, according to Stephen Selby one Tang-era exam required over thirty shots with a 76kg (167.5lb) bow at 105 paces. From a military perspective, using a bow you can just barely draw and release doesn't make a lot of sense. Military archery benefits from accuracy, endurance, and speed of shooting. While surely some historical warriors were overbowed for various reasons - declining strength from illness or poor nutrition on campaign, wanting to show off, etc. - I suspect most carried the heaviest bows they could shoot comfortably.
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Cs. Norbert
Location: Romania Joined: 21 Aug 2015
Posts: 27
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| Posted: Sun 20 Sep, 2015 4:02 pm Post subject: |
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In reply to Dan Howard
| Quote: | Williams tested one type of mail out of the hundreds that we have extant. Some of them have weaves that are denser than that tested by WIlliams and others do not. Lighter mail would be more susceptible to arrows and the heavier ones would not. The heaviest ones are completely proof against any kind of bow. One issue with the heavier weaves is that you start to lose flexibility. In some circumstances it is better to wear two layers of light mail rather than one heavy layer because you retain more flexibility. In some hauberks you see dense, heavy links in vulnerable places such as the chest and neck and lighter, more open links in places that are less likely to get hit, such as the back and left side.
It doesn't matter whether it is made of modern steel or not. If you shoot an arrow at 3mm plate, there is no way that it would penetrate regardless of what kind of steel it was. The heaviest types of mail protect just as well as that 3mm plate. One problem is that these kinds of mail are a lot heavier than plate. |
I don't know how common were those (apparently very heavy) mails with dense weaves (they might be as rare as high quality milanese plate was, shortly after they appeared), or if most historians would consider them as a "standard" for high quality mail, but yes I do believe that those examples, will protect the wearer against all arrow weights regardless of bow power! Armor weight is relevant even when on horse, depending on terrain, tactics (how well can they maintain formations, or if they can maintain the advantage that the horse offers in terms of speed and mobility, a mounted knight that is static would make an easier target, especially if its not backed up by supporting troops, and can be thrown of the horse), the mounted knight might be forced by circumstances to fight on foot, and a heavy armor would have a great impact on mobility (considering the heavy dense waves with less flexibility) and stamina (even if the weight of the armor is distributed more uniformly, per limbs and torso, the legs will have to carry that weight, and the arms will have a considerable additional weight). Regarding the issue of heavier waves that are more rigid, versus those lighter ones, I believe that this would be a considerable advantage, we already know that the heavy denser wave mail cannot be penetrated, so we don't need to make it more flexible to absorb the KE of the arrow if it's already impenetrable because of thickness. Being more flexible would mean more energy will be transferred to the organs because of very high deformations (if heavy arrows are used), I imagine that padding (this is what contributes to overheating, and in some cases when the padding is a tough gamberson it is considered armor) would be light, so it would do a poor job of preventing internal injuries! Even if padding is not light, considering the effects (chain links that would be stuck in flesh with light padding) the medium heavy (for heavy bows) arrows had in Bane's testings, with a bow that is just at the limit (of poundage for english warbows) of being considered a warbow, the internal injuries would be considerable if chain is too flexible!
Yes the "high quality armor" (from Bane's perspective is high), might be inferior to the one that williams tested, thus the difference in ke needed for penetration, and even what williams considered high quality mail, might not be the best mail if your notion of high quality mail is related to the mail in the attached pictures! I think that the energies (for bane's ~60J) to penetrate those mail types (from bane's and williams's tests) are close to reality, the issue is, the different interpretations of "high quality mail" ! I believe that thick padding (being too thick would be impractical because of overheating) under the flexible mail, is not enough to prevent serious internal injuries if heavy arrows are used! If the heavy dense wave mail is used, the padding would suffice even if not too thick!
In reply to Timo Nieminen
| Quote: | Yes, the light to heavy arrow range for English warbows is heavier than the light to heavy arrow range for the much lighter-limbed Asian reflex-recurve bows. 50g to 100+ g, vs 20-40g.
The point remains: If you shoot a 10g arrow from a 170lb English warbow (and the arrow survives, and ignoring energy lost in flexing the arrow), the arrow will have a higher speed than a 50g arrow shot from the same bow. And a 400g arrow will have less speed and more energy.
I don't see what your point was. Can you clarify? |
Sorry, this is my bad because I wasn't clear enough! Yes for all bow types, shooting a lighter arrow translates to a higher speed, but not all behave the same, and apparently the english longbow is more limited in terms of speed increases from lighter arrows (compared to modern compounds and traditional recurve-composites). Sure, it might be worth some few yard increases in range (if using heavier english bows) if the purpose is only range with light arrows (not too light like 10g, because of it's efficiency limitations with light arrows, which would translate in returns that are too diminished, and there is also the safety issue) (and as you stated, light for english longbows is not the same as light for other types, because of the difference in bow design and efficiency with different arrow weights). In conclusion, the speed advantage you gain with light arrows (using the english longbow) is not enough to outweigh the performance gains (in momentum and penetration) using heavier arrows (assuming that you don't go in the too heavy extreme) when talking of military efficiency and not range competitions! For my previous statement (theory, since I can't prove it more clearly than that) I used as arguments the EWBS examples in the discussion with Benjamin H. Abbott!
| Quote: | Where does that MR bow efficiency come from? "According to some studies" isn't enough for me to find it.
Historical weights for Turkish/Indian/Korean/Chinese arrows are known, historical weights for English warbow arrows are known. Weights of the bows are known. An English warbow is heavier than an Ottoman/Indian/Korean military bow. So the arrow mass giving a good compromise between speed and energy is different (and heavier).
To look at this properly, it isn't enough to know the efficiency for a single arrow mass; you need to know how the efficiency varies with arrow mass. Karpowicz's test give this. Do you know of similar tests for English warbows? Don't need the efficiency as such; arrow speed vs arrow mass is enough, if the arrow mass varies enough.
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The MR bow efficiency is estimative and comes from: various physics thesis on archery (some have the efficiency of 0.7 others 0.9) and http://www.dryadbows.com/Defining%20Bow%20Performance%20Dryad.pdf . ! I don't believe that this formula with an average value for efficiency, is accurate, but I tested both the 0.9 (at 12.67 gr/lb from bane's formula) and the 0.7 (at 9 gr/lb, with increments of 0.1 eff for every 1 gr/lb) with the formulas used in bane's calculations, and I found that, the 0.7eff for 9 gr/lb gave me results that are close to the performances of some longbow tests vs the other one that gave me performance results close to composite recurves! I don't have many relevant examples of arrow speeds with different arrow masses for the 2 bow types (I don't consider the bows that were used in penetration tests as relevant, because they might not be the best performers in that lb category, EWBS bows that set records should be considered relevant, because that competition stimulates the increase in bow performance to achieve better results). I didn't use any formula for the examples I gave you (175lb MR replica is an efficient bow made by Ian, used by Joe to brake 2 records, at livery and 1/4 lb arrow category)! We also have the chronometered speed of the livery arrow which is >210 fps! For 1/4 lb performance comparison we have the 155 lb MR replica bow that has almost the same performance as the 175lb one (that Joe used)! The 136lb@28.9" turkish bow in that ex. has a 1067gr arrow speed of 210.3 fps. It's not an accurate performance comparison, but is enough to give you an idea of the ~performance at that arrow weight! Using EWBS records can give you an idea of the english longbow performance with different arrow grains (unfortunately we only have 4 arrow types, only 2 that are more relevant when talking of military efficiency) and how the increase in draw weight affects it! Because of the small differences in performance increase from 155lb to 175lb (considering these bows would be the most efficient in their classes, and the persons shooting them are experienced archers that can control them) I concluded that, the increase in draw weight from the 175 lb bow to very well made 200lb would give very small gains in performance (for the arrows that have weights of military relevance) than the increase from the 155 to 175lb, thus it is not worth the increase!
| Quote: | Not specifically referring to Ashby's tests, but Ashby's tests do show the importance of momentum in penetration into animal tissue. Note also that Ashby shows the importance of viscous drag, with the effect of arrow diameter on penetration depth. Tissue is very much a viscous drag environment. Same thing applies for shooting arrows into water (e.g., in bowfishing). Why does the arrow slow down? The same thing will happen in tissue.
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I don't have a problem with the viscous part, but the drag part is not the same, and if you used water for ex. the flow of water affects the arrow shaft and creates more drag, in tissue the arrow head expands the wound and the shaft doesn't have drag (or is minimal). Regarding Ashby's arrow penetration, the momentum might be more important in penetration because of the bow he used, which favors the higher weight arrows, and doesn't generate enough speed with lower weight arrows vs the modern compounds. So in his context, Ashby is right, for the momentum importance, also he puts more accent on arrow FOC than weight! In the next ex. we have some penetration tests (which doesn't invalidate Ashby's study like the author hoped) https://www.youtube.com/watch?v=VAfK0sBsZBw .
| Quote: | Basically, why you want something under your mail when facing high energy arrows.
150J to an unpadded target wouldn't be very nice. That's about the same energy as delivered by beanbag rounds. Beanbag rounds don't tend to severely injure (by design), so that kind of energy spread over a beanbag area isn't so bad, but it does tend to encourage people to stop fighting (which is the point).
If the mail is light enough so that you can penetrate the mail (and the underpadding), then you don't need much energy to do a lot of damage - you've put a sharp arrowhead in flesh. Sure, sometimes just hitting the mail, without penetration, can be better. Mace, club, warhammer might do better than a sword that doesn't penetrate. The questions is how much damage an arrow can do, with the energy left after moving/compressing mail and padding. |
With light padding and "high mail quality" you can see the deformations in the clay in Bane's testings (considering the low lb bow), with my approximation of ~60J of energy to cause those deformation (or bane's 73J)! Double that KE and try to estimate what that arrow would do! Every inch of penetration after deep deformation is more damaging than an inch of penetration with low deformation!
In reply to Will S
| Quote: | Just a point or two - its useless using EWBS flight records in an investigation regarding military penetration etc. The arrows are FLIGHT arrows. Granted they're roughly based on mediaeval arrows but by no means whatsoever are they the same thing. They are simply a piece of modern sporting equipment developed and tweaked by individuals to achieve a long distance when shot.
The "standard" arrow for instance is a concoction dreamt up by a couple of people using whatever they had on hand at the time (this is from a conversation I had with Mark Stretton last week on the matter) and bears almost zero resemblance to a mediaeval arrow.
The only arrow used in EWBS flight records that is worth taking any notice of is the Livery arrow. This is the only one based exactly on extant arrows (from the Mary Rose) along with the Westminster Arrow which is rarely shot in competition. Even then, the arrows used for flight records are the absolute lightest, fastest arrows available within the given specifications.
Also, using draw weights as your primary focus point shows a serious lack of understanding of bows in general. I don't mean to be rude at all, but I can assure you that draw weights are meaningless in this context. One well made 120lb bow will outshoot, outperform and give vastly different results in all of your tests to a badly made 180lb bow.
Add to that the fact that if an archer is shooting a bow at his weight limit, he will almost always be outshot by an archer who is comfortable. That is to say, if "Archer A" is shooting a very well made 160lb bow but finds it difficult to reach full draw, he will always be beaten in distance and performance by "Archer B" shooting a 120lb bow, if Archer B isn't struggling to get to full draw.
This is why your analysis is only touching the absolute surface, and why a better understanding of the shooting and making of heavy warbows is necessary to do tests like these. Otherwise all you're doing is combining written data from numerous sources into one place and trying to produce a result. Written data on bow performance is only useful if you also know exactly the state of the archer, the weather, the humidity, the quality of the bow, the age of the bow, the decrease in performance of the bow since new, the arrow weight, the fletching shape, the arrow quality (how well was it fletched, how thick is the binding) and so on. |
The EWBS flight and standard arrow category was mentioned only in the discussion with Benjamin H. Abbott, and was more related to the range performance of the bow instead of penetration! The other 2 bow examples (175lb and 155lb) from EWBS used the tudor livery arrows and the heavy 1/4 lb (which according to them it might resemble the lozenge arrow)! You can consider all the arrows flight arrows (even the 1/4 lb one) but we are comparing apples to apples when we want to find out the increase of arrow speed by using lighter arrows vs heavy from different (highly effective) bows! I don't know how much you can improve the flight of a 1/4 lb arrow, but the performance difference between those arrow types are more relevant than the performance difference between a 1/4lb war arrow and the 1/4 lb "flight arrow". If the difference exists, I doubt that is significant! The 120 lb bow vs the badly made 180 lb bow, is not relevant if we consider the record breaking bows that I mentioned, by that logic you would suggest that the 175 lb bow that Ian made for Joe under-performs and that's why the 155lb bow has the same performance with 1/4 lb arrow.
"Add to that the fact that if an archer is shooting a bow at his weight limit, he will almost always be outshot by an archer who is comfortable. That is to say, if "Archer A" is shooting a very well made 160lb bow but finds it difficult to reach full draw, he will always be beaten in distance and performance by "Archer B" shooting a 120lb bow, if Archer B isn't struggling to get to full draw." This is not the case in Joe vs Alistair Aston, since Alistair Aston had the same performance as Joe with a lighter lb bow and we all know that Joe doesn't struggle too much to draw the 175 lb bow! I believe that with very heavy arrow weights, the increase in range would be very small even if someone would use an efficient 200 lb bow and be able to maintain proper technique at full draw (that is if it doesn't under-perform and not because it isn't well made but because of the diminishing returns that you get by using a heavier draw lb bow)! At tudor livery arrow weights you will get larger range differences between the 175lb bow and the 155lb, because of the speed difference and the flight trajectory of the arrow (the heavier arrow is not that affected by drag but gravity will have a high impact after the apex).
I agree that it would be best to test the bows in a controlled environment with maybe a mechanical device for releasing the string to make sure you draw all the bows at the same length, and also to be sure you can draw the heavy bows, but we can only work with what we have! Even if someone would do a controlled test of those bows with different arrow weights of the same type, there would be some that would argue that the results would have been different because the medieval yew had different properties, or the bows might not be the best performers in their category because of bow maker's skill and another bow maker would be able to make a more efficient bow...!
| Quote: | The strength of archers is very different to the strength of bows. You could theoretically take 10 identical bows (in poundage, profile, tiller shape, timber, mass and cast) and give them to 10 different archers. It would always be the stronger ARCHER who shoots further.
In my opinion, its this understanding of bows and the shooting of them that is more important than simply looking at a table of data on the EWBS flight records and basing research on it. It's meaningless when discussing armour penetration or performance of a particular bow. |
If you give the same bow to those 10 archers, the one that has a greater strength will be able to hold the bow at full draw more comfortably, and he will do a controlled release at the trajectory he aimed (and had enough time to to it well). Small differences will occur, even if the same person would use the same bow many times! The increased strength of that archer doesn't necessarily translate to high skill, you can have a strong archer that is not better skilled!
To compare strong archers to those that cannot properly draw their bow at the full length with proper form, is like comparing two pilots where one of them doesn't reach the acceleration well enough to push it to the max! Why would an experienced archer draw a bow that he cant properly control?
When discussing armor penetration we should be focusing on KE, every armor would have a different minimum required ke (for different arrow head types) to be penetrated, and it doesn't matter if you achieve that ke by struggling with a heavy and badly made bow or a light and well made bow! What matters is the arrow weight and speed to achieve that ke.
To Timo Nieminen
| Quote: | If all 10 archers can draw the bows to full draw, why would there be a difference?
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| Quote: | | Given sufficient strength and technique/skill, how large do you think the improvement in terms of delivered energy might be if the archer had more strength and more skill? Large enough to range/penetration tests meaningless, or a small enough improvement so that it's lost in the noise? |
I think he's referring to the controlled release that Joe has, which translates to a more accurate placement at the desired trajectory and more importantly an increase in early arrow flight stability and reduced bow and arrow vibrations (that translate to a loss in ke)! Suppose you give the bow that Joe uses to the other 9 and suppose that they will struggle more but are able to reach the same draw length that Joe had, they won't have that controlled release but if you give them enough tries, their best range might be close (but they won't match it) to Joe's (if heavy arrows are used) depending on arrow weight, if using lighter arrows the difference is amplified! These differences is range are not high enough to be translated to significant increases in penetration! The KE increase is insignificant in penetration tests (which have a high margin of error, the armor quality varies greatly and the estimation of armor resistance to penetration has a high margin of error). Ex supposing that a plate needs ~150J to be defeated (the "~" means that is a range between 2 values, because the hardness and toughness estimates are in ranges and an average value is chosen, that doesn't mean that the chosen value will correctly represent the result), shooting the same bow by the same person gives a range of results
that might be below 150 and some above, if lucky enough we have 2 similar arrow strikes at the same speed that by calculation give the same ke, even that doesn't mean that the penetration range will be the same, it will also be a range!
Trying to quantify the skill of the archer in relation to bow intrinsic performance just over-complicates the already complicated equation for a reasonable ke estimate! My opinion is that the difference in ke (because of differences in strength and skill) at short range, is not large enough to be considered, and can be included in the margin of error. Some penetration tests were conducted by the same archer shooting the same bow or different bow weights, in this context the skill and strength is nor relevant anymore). If judging EWBS performances (mainly records) I think is safe to say that Joe's rivals shoot bows that they can draw at full length and were able to control them with a certain degree of comfort (so skill and strength didn't produce the large differences in range, I believe that bow performance mattered the most, and Joe's skill just gave him a slight edge, supposing that the other archer's bow is almost equal in performance to Joe's).
Not drawing the bow fully will translate in a considerable loss in performance (depending on the length difference and bow's release power curve/inch which can be different for 2 bows with the same lb at the same max draw) , similar to using a lighter lb bow. I believe that this was not the case in the EWBS examples! Small differences in draw length are present at every draw for the same individual, this is one of the main reasons for the range and ke high margin of error!
To Will S
| Quote: | | Well this is where it gets difficult. The questions you're asking however are exactly the questions that need to be asked - just assuming draw weight equals result is why I think the original post is so far wide of any useful information. |
I didn't assume that same max draw weights results the same results (I'm aware of the bow power/inch curve at release), but if the bows are very similar in properties you can include those differences in a margin of error, that is we are comparing the same bow types not traditional english selfbows with flatbows of different materials, or with recurves!
[/quote]However (and this is purely my opinion based on watching people like Joe shoot) I would say in your first scenario the archer who can shoot 150lb would perform best with the 100lb bow. The archer who can just shoot 100lb is out of the equation as he will be struggling to reach full draw therefore no focus is placed on technique of loose. The archer who can shoot 200lb may have pure brute strength and be able to heave back the weight, but may have poor loose technique still. The archer shooting 150lb has "excellent" technique and has a clean, powerful loose. The 100lb weight isnt near his limit so no strain is getting in the way of form and he can focus purely on a smooth, fluid rolling loose.
Mark Stretton has spoken in some detail about the difference between an archer who can DRAW 140lb and the archer who can SHOOT 140lb. There is a vast difference.
There is a guy here in the UK who can draw (just about) 170lb bows. There is very little doubt however that given a straight distance competition between himself and Joe, Joe would beat his distance by a large margin. He is so much more comfortable at that weight that his form and technique are able to be utilised, unlike the guy who is using all of his might to get back to 32" and letting it go in a great release of strain with a clumsy, aggressive loose and bad timing.
If you personally could just about shoot 120lb for instance, and were competing for distance using a 90lb bow against somebody who could just draw 100lb (also using a 90lb bow) you would win.
Whether this has an impact on penetration of armour I couldn't say, but I would imagine a fluid, clean loose would make a difference? | Quote: |
If Joe would beat that guy's distance by a large margin (assuming that Joe gives he's bow to the other archer after he shoots to eliminate the differences in bow performances), we can assume that light arrows are used, and the large difference would come from the differences in draw length and lack of consistency after the first few releases, while Joe will improve it's distance, and draw length will stay the same, the other guy will get worst performances with each shot, and it's possible that he's first shot will be it's best (only if he's lucky enough to aim at the perfect angle from the first shot, which is improbable). As he gets tired and draw length is more reduced, Joe's draw length is consistent, his appreciation of the best launch angle improves and along with the slight edge that the rolled release gives him it will ultimately translate to a considerable range difference! Regarding the 120lb draw potential vs the other which has the 90 lb potential on the 90 lb draw competitions, it's logical that the one with 120lb potential would win, but it's not relevant when talking about experienced archers that know their limits and how to choose their bows for a "comfortable" draw in the long run. My opinion is that: the rolled release give's a slight edge that differs with arrow weight, the difference in draw length (when talking of full inches differences) gives high differences in performance, and bow performance (more related to the power/inch curve at release) which ultimately gives the highest differences and the differences in draw lengths are proportional with these. The loss in power from a shorter draw is proportional to the bow's draw/release force curve at every inch with the same arrow! Regarding armor penetration, I believe that it would make a difference, but not a considerable one, and short range along with heavy arrow would translate to even a smaller increase!
To Benjamin H. Abbott
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Certainly it's important for archers to master their bows rather than struggle with them. Assuming most of the archers on Mary Rose were shooting 150-160lbs bows as the estimates go, that presumably means they could skillfully shoot these weapons while at sea. The various officer exams in the Chinese region that required pulling heavy bows likewise often (not always) required the people tested to shoot such heavy bows accurately and repeatedly. For example, according to Stephen Selby one Tang-era exam required over thirty shots with a 76kg (167.5lb) bow at 105 paces. From a military perspective, using a bow you can just barely draw and release doesn't make a lot of sense. Military archery benefits from accuracy, endurance, and speed of shooting. While surely some historical warriors were overbowed for various reasons - declining strength from illness or poor nutrition on campaign, wanting to show off, etc. - I suspect most carried the heaviest bows they could shoot comfortably. | Quote: |
I have the same point of view, and I would put the accent on " From a military perspective, using a bow you can just barely draw and release doesn't make a lot of sense" and " I suspect most carried the heaviest bows they could shoot comfortably".
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Timo Nieminen
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| Posted: Sun 20 Sep, 2015 5:14 pm Post subject: |
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| Cs. Norbert wrote: |
In reply to Timo Nieminen
| Quote: | Yes, the light to heavy arrow range for English warbows is heavier than the light to heavy arrow range for the much lighter-limbed Asian reflex-recurve bows. 50g to 100+ g, vs 20-40g.
The point remains: If you shoot a 10g arrow from a 170lb English warbow (and the arrow survives, and ignoring energy lost in flexing the arrow), the arrow will have a higher speed than a 50g arrow shot from the same bow. And a 400g arrow will have less speed and more energy.
I don't see what your point was. Can you clarify? |
Sorry, this is my bad because I wasn't clear enough! Yes for all bow types, shooting a lighter arrow translates to a higher speed, but not all behave the same, and apparently the english longbow is more limited in terms of speed increases from lighter arrows (compared to modern compounds and traditional recurve-composites). Sure, it might be worth some few yard increases in range (if using heavier english bows) if the purpose is only range with light arrows (not too light like 10g, because of it's efficiency limitations with light arrows, which would translate in returns that are too diminished, and there is also the safety issue) (and as you stated, light for english longbows is not the same as light for other types, because of the difference in bow design and efficiency with different arrow weights). In conclusion, the speed advantage you gain with light arrows (using the english longbow) is not enough to outweigh the performance gains (in momentum and penetration) using heavier arrows (assuming that you don't go in the too heavy extreme) when talking of military efficiency and not range competitions! For my previous statement (theory, since I can't prove it more clearly than that) I used as arguments the EWBS examples in the discussion with Benjamin H. Abbott!
| Quote: | Where does that MR bow efficiency come from? "According to some studies" isn't enough for me to find it.
Historical weights for Turkish/Indian/Korean/Chinese arrows are known, historical weights for English warbow arrows are known. Weights of the bows are known. An English warbow is heavier than an Ottoman/Indian/Korean military bow. So the arrow mass giving a good compromise between speed and energy is different (and heavier).
To look at this properly, it isn't enough to know the efficiency for a single arrow mass; you need to know how the efficiency varies with arrow mass. Karpowicz's test give this. Do you know of similar tests for English warbows? Don't need the efficiency as such; arrow speed vs arrow mass is enough, if the arrow mass varies enough.
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The MR bow efficiency is estimative and comes from: various physics thesis on archery (some have the efficiency of 0.7 others 0.9) and http://www.dryadbows.com/Defining%20Bow%20Performance%20Dryad.pdf . ! I don't believe that this formula with an average value for efficiency, is accurate, but I tested both the 0.9 (at 12.67 gr/lb from bane's formula) and the 0.7 (at 9 gr/lb, with increments of 0.1 eff for every 1 gr/lb) with the formulas used in bane's calculations, and I found that, the 0.7eff for 9 gr/lb gave me results that are close to the performances of some longbow tests vs the other one that gave me performance results close to composite recurves! |
Efficiency of about 0.7 looks pretty normal, for arrows of suitable weight. The typical good compromise between speed and energy should be achieved for arrow masses giving efficiencies of about 0.6-0.7. (For an ideal bow, with no losses to hysteresis or the flexing the arrow, at an efficiency of 0.62, you get 0.62 of the maximum possible speed. (Actually at e = (sqrt(5)-1)/2; the fraction of maximum arrow speed obtained is sqrt(1-e).))
The question is what arrow weight gives that efficiency. For your calculations, it looks like 9gpp for a longbow, which is about the historical arrow weight. For Turkish bows, about 4-5gpp. For Japanese and Manchu bows, 15gpp judging by historical arrow weights.
| Cs. Norbert wrote: | | With light padding and "high mail quality" you can see the deformations in the clay in Bane's testings (considering the low lb bow), with my approximation of ~60J of energy to cause those deformation (or bane's 73J)! Double that KE and try to estimate what that arrow would do! Every inch of penetration after deep deformation is more damaging than an inch of penetration with low deformation! |
Typical less-than-lethal munitions (e.g., riot control munitions) are in the general range of high-energy archery for mass, speed, and energy:
https://en.wikipedia.org/wiki/Baton_round
The early British rubber bullets (1970-75) far exceeded 200J, and were not supposed to be used to directly shoot people (instead, they were supposed to be bounced off the ground); these could and did kill. The latest plastic bullets deliver under 250J, and can still injure or kill. But will not usually seriously injure.
For details of the various rounds: http://www.smallarmsreview.com/display.articl...icles=1331
For some info on injuries:
http://emj.bmj.com/content/22/2/111.abstract
http://emj.bmj.com/content/24/2/103.abstract
Bean bag rounds deliver less energy (about 150J), and cause fewer injuries and deaths.
If interested in the possibility of militarily effective blunt force trauma caused by arrows through armour, the research on less-than-lethal munitions is a good start. 60-70J doesn't appear to be too dangerous.
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Will S
Location: Bournemouth, UK Joined: 25 Nov 2013
Posts: 164
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| Posted: Sun 20 Sep, 2015 6:39 pm Post subject: |
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| Cs. Norbert wrote: | | I think is safe to say that Joe's rivals shoot bows that they can draw at full length and were able to control them with a certain degree of comfort (so skill and strength didn't produce the large differences in range, I believe that bow performance mattered the most, and Joe's skill just gave him a slight edge, supposing that the other archer's bow is almost equal in performance to Joe's). |
| Cs. Norbert wrote: | | not drawing the bow fully will translate in a considerable loss in performance (depending on the length difference and bow's release power curve/inch which can be different for 2 bows with the same lb at the same max draw) , similar to using a lighter lb bow. I believe that this was not the case in the EWBS examples! Small differences in draw length are present at every draw for the same individual, this is one of the main reasons for the range and ke high margin of error! |
Both these statements are incorrect, and are why I think using data from EWBS flight shoots is the wrong direction to go in. Believe me - I regularly attend EWBS shoots, and was present at the ones you are using for data. There are plenty of archers shooting bows well beyond their comfort level (myself included) and many weren't even at full draw.
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Cs. Norbert
Location: Romania Joined: 21 Aug 2015
Posts: 27
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| Posted: Mon 21 Sep, 2015 2:16 am Post subject: |
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| Quote: | Typical less-than-lethal munitions (e.g., riot control munitions) are in the general range of high-energy archery for mass, speed, and energy:
https://en.wikipedia.org/wiki/Baton_round
The early British rubber bullets (1970-75) far exceeded 200J, and were not supposed to be used to directly shoot people (instead, they were supposed to be bounced off the ground); these could and did kill. The latest plastic bullets deliver under 250J, and can still injure or kill. But will not usually seriously injure.
For details of the various rounds: http://www.smallarmsreview.com/display.articl...icles=1331
For some info on injuries:
http://emj.bmj.com/content/22/2/111.abstract
http://emj.bmj.com/content/24/2/103.abstract
Bean bag rounds deliver less energy (about 150J), and cause fewer injuries and deaths.
If interested in the possibility of militarily effective blunt force trauma caused by arrows through armour, the research on less-than-lethal munitions is a good start. 60-70J doesn't appear to be too dangerous. |
Sending an arrow at which has has a potential energy of 150J (because of speed and mass) doesn't translate in the same results from sending another different projectile with a potential energy of 150J! For penetration, you can clearly see that bullets need far more ke then arrows to achieve the same effect! I don't believe that a rubber projectile (with 150j) transmits those joules in the same way to the target, the rubber bullet mostly transmits an intense shock for a very short period of time, the shock propagates without huge deformations! The impact energy is quickly dissipated! The arrow concentrates that energy and it acts for a longer time generating significantly more trauma /cm2! So 2 different projectiles with the same ke don't achieve the same results ! Another way to put this would be: the human brain can resist to trauma caused by high intensity / very short acting time, but if using lower intensity and a longer acting time, you can produce permanent brain injuries (possibly death)!
To Will S
I know that not all of the competitors have the same skill and some (maybe a large part of them) might use bows that are at their limit of lb draw, but I didn't state that all examples from EWBS are relevant, in fact this is one of the main reasons why I only extracted 2 relevant (at least from my point of view) examples! I really doubt that Joe didn't use the bow's maximum potential to achieve the 2 records with that bow, and I also doubt that Alistair didn't use he's bow maximum potential to achieve the previous record, that Joe broke with only 1 yard difference (at 1/4 lb arrows).
Also when Joe broke his own record of 290 yards at (tudor livery), where does skill and strength differences play a part on that?
Regarding what you previously stated: that I'm just collecting data from different source, and extrapolating results, well you are right, I can't afford a controlled test to have results that are almost indisputable, I can only use what I know so far to create a rough estimate with a high margin of error! I'm just hopping that with your help (referring to you and all that contributed to the topic) we might be able to reduce that high margin of error, by putting our minds together and collecting as much data on the subject as we can, and sorting that data by relevancy! To give an idea of the large margin of error in my estimation regarding armor penetration I will use a oversimplified example: I know that a 2mm plate made from wrought iron with slag ~2%, and a V hardness of over 170, and fracture toughness somewhere between 190 and 170 kj/m2, can be defeated (at close range) by a heavy arrow with a short bodkin head (there are different types of short bodkins) that is not intentionally hardened, that arrow being sent from a bow with 160lb@32" generating over 150J!
What would that arrow to do to a better armor (between high quality milanese and high quality iron) at the same range?
What is the maximum ke that a heavy (where would be the limit of lb where the bow doesn't give worthy returns by the increase in lb) longbow can generate with it's best arrow (referring to the compromise between speed and weight) at close range (to eliminate other complications that affect impact ke). Supposing the maximum would be a range, or to put it another way, an estimated value with a certain margin of error, what would that arrow do to different breast plate armor quality considering that we keep a constant of 2mm thickness (just for simplicity)?
For some this might seem a waste of time, because of their standard in accuracy of results, but while we wait for someone to do the ideal controlled tests that would give those accurate results, we can use the data we have so far to narrow the margin of error (or I'm just hopping that we could do that)! I believe that using the relevant data from all the impact tests and from different studies like williams's, corroborated with the performance results of the longbow from different modern testings, we could make an estimation on what it would take to defeat a specific armor type, or what armor types (with different properties) would a specific bow (oversimplification), be able to defeat!
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Timo Nieminen
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| Posted: Mon 21 Sep, 2015 5:52 pm Post subject: |
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| Cs. Norbert wrote: | | Quote: | Typical less-than-lethal munitions (e.g., riot control munitions) are in the general range of high-energy archery for mass, speed, and energy:
https://en.wikipedia.org/wiki/Baton_round
The early British rubber bullets (1970-75) far exceeded 200J, and were not supposed to be used to directly shoot people (instead, they were supposed to be bounced off the ground); these could and did kill. The latest plastic bullets deliver under 250J, and can still injure or kill. But will not usually seriously injure.
For details of the various rounds: http://www.smallarmsreview.com/display.articl...icles=1331
For some info on injuries:
http://emj.bmj.com/content/22/2/111.abstract
http://emj.bmj.com/content/24/2/103.abstract
Bean bag rounds deliver less energy (about 150J), and cause fewer injuries and deaths.
If interested in the possibility of militarily effective blunt force trauma caused by arrows through armour, the research on less-than-lethal munitions is a good start. 60-70J doesn't appear to be too dangerous. |
Sending an arrow at which has has a potential energy of 150J (because of speed and mass) doesn't translate in the same results from sending another different projectile with a potential energy of 150J! For penetration, you can clearly see that bullets need far more ke then arrows to achieve the same effect! I don't believe that a rubber projectile (with 150j) transmits those joules in the same way to the target, the rubber bullet mostly transmits an intense shock for a very short period of time, the shock propagates without huge deformations! The impact energy is quickly dissipated! The arrow concentrates that energy and it acts for a longer time generating significantly more trauma /cm2! So 2 different projectiles with the same ke don't achieve the same results ! Another way to put this would be: the human brain can resist to trauma caused by high intensity / very short acting time, but if using lower intensity and a longer acting time, you can produce permanent brain injuries (possibly death)! |
Compare the masses (40-130g) and speeds (60-70m/s is typical). Not just similar energy, but also similar momentum. Once the arrow impact is spread by armour and padding, why would there be such a difference? Arrows aren't magic - hit somebody with 100g moving at 60m/s, with the impact spread over the same area, and the effect will be similar. Why would it matter if it's a plastic bullet, shot in a bag, or a wooden stick?
Since 150J of blunt impact delivered to an unprotected torso usually doesn't result in serious injury, it's unlikely that arrows that fail to penetrate armour are that dangerous (i.e., unlikely to kill or seriously injure), as long as the armour spreads the impact over a similar area (about 6cm^2, or 1"x1").
But note that 150J is effective for encouraging surrender.
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Cs. Norbert
Location: Romania Joined: 21 Aug 2015
Posts: 27
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| Posted: Tue 22 Sep, 2015 8:34 am Post subject: |
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| Timo Nieminen wrote: | | Cs. Norbert wrote: | | Quote: | Typical less-than-lethal munitions (e.g., riot control munitions) are in the general range of high-energy archery for mass, speed, and energy:
https://en.wikipedia.org/wiki/Baton_round
The early British rubber bullets (1970-75) far exceeded 200J, and were not supposed to be used to directly shoot people (instead, they were supposed to be bounced off the ground); these could and did kill. The latest plastic bullets deliver under 250J, and can still injure or kill. But will not usually seriously injure.
For details of the various rounds: http://www.smallarmsreview.com/display.articl...icles=1331
For some info on injuries:
http://emj.bmj.com/content/22/2/111.abstract
http://emj.bmj.com/content/24/2/103.abstract
Bean bag rounds deliver less energy (about 150J), and cause fewer injuries and deaths.
If interested in the possibility of militarily effective blunt force trauma caused by arrows through armour, the research on less-than-lethal munitions is a good start. 60-70J doesn't appear to be too dangerous. |
Sending an arrow at which has has a potential energy of 150J (because of speed and mass) doesn't translate in the same results from sending another different projectile with a potential energy of 150J! For penetration, you can clearly see that bullets need far more ke then arrows to achieve the same effect! I don't believe that a rubber projectile (with 150j) transmits those joules in the same way to the target, the rubber bullet mostly transmits an intense shock for a very short period of time, the shock propagates without huge deformations! The impact energy is quickly dissipated! The arrow concentrates that energy and it acts for a longer time generating significantly more trauma /cm2! So 2 different projectiles with the same ke don't achieve the same results ! Another way to put this would be: the human brain can resist to trauma caused by high intensity / very short acting time, but if using lower intensity and a longer acting time, you can produce permanent brain injuries (possibly death)! |
Compare the masses (40-130g) and speeds (60-70m/s is typical). Not just similar energy, but also similar momentum. Once the arrow impact is spread by armour and padding, why would there be such a difference? Arrows aren't magic - hit somebody with 100g moving at 60m/s, with the impact spread over the same area, and the effect will be similar. Why would it matter if it's a plastic bullet, shot in a bag, or a wooden stick?
Since 150J of blunt impact delivered to an unprotected torso usually doesn't result in serious injury, it's unlikely that arrows that fail to penetrate armour are that dangerous (i.e., unlikely to kill or seriously injure), as long as the armour spreads the impact over a similar area (about 6cm^2, or 1"x1").
But note that 150J is effective for encouraging surrender. |
What you are stating makes sense, that the KE similarity should produce similar results, but the round head of the plastic bullet is not designed to penetrate on contact, and it shouldn't produce the same deformation depth as the diamond shaped arrow, thus the plastic bullet produces trauma by hydrostatic shock, and the arrow that failed to penetrate produces damage by both, hydrostatic shock and depth of deformation which amplifies (if deep enough) the probability of internal injuries! Bane correlated his penetration deformations (see http://www.currentmiddleages.org/artsci/docs/...esting.pdf page 17 figure 42 ) in the clay with NIJ standard ( https://www.princeton.edu/~ota/disk1/1992/9230/9230.PDF Origin and Rationale of the 44-mm BFS Limit ). The question is: how accurate are bane's penetration tests parameters compared to NIJ? Should the 1.7" BFS depression limit still apply in Bane's test, or it should be higher! I would imagine that an arrow with double the amount of ke, should cause higher deformations to a better mail (better then that used by bane or williams to have a small chance of stopping the arrow) if the elasticity is similar, but I can't quantify how much role the hydrostatic shock damage had in NIJ test (since bullets have a much higher velocity)!
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Timo Nieminen
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| Posted: Tue 22 Sep, 2015 2:59 pm Post subject: |
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While the arrow alone is designed to penetrate (and a penetrating arrow will behave very differently from a plastic bullet), the arrow + mail + padding is designed to not penetrate (from the perspective of the target). As long as the impact is spread over 1"x1" by the armour and padding, why would there be a large difference? (Look at Bane's photos - for the non-penetrating arrows, how wide is the deformation?)
A plastic bullet is typically a little heavier than an English warbow arrow, and a little faster. To claim that it causes less deformation than an arrow that is stopped by mail + padding seems rather incredible. At the very least, that claim needs experimental support. Claiming that a leftover 60-75J or so (after deforming and moving the mail and compressing the padding) is likely to cause serious injury or kill when 250J of plastic bullet usually doesn't just looks like highly partisan wishful thinking.
Rejecting data available on hitting humans with projectiles of similar weight and speed as arrows in favour of data on shooting animals and tissue simulants with bullets of 1/10 to 1/5 of the mass, and 5 to 10 times the speed also looks dubious.
150-250J of blunt projectile works quite well for stopping humans. Contemporary accounts like "When he was drawing (i.e. shooting) at the besiegers his shooting was registered by everyone because he either struck and seriously wounded those who were unarmoured, or put to flight those whom he aimed at with the arrows he shot, astounded - battered but not wounded since they were armoured." make sense (see http://myArmoury.com/talk/viewtopic.php?p=297673 for discussion of this passage).
Given the bad PR when people are killed by less-than-lethal munitions, even if not very often, if lower energies worked reliably for stopping people, they would be used. The 150J beanbag round looks like an effective minimum (the higher energy rounds are designed for longer ranges, and there are higher energy beanbag rounds designed for longer ranges; the 150J beanbag is used at short ranges (sometimes just a few metres).
(150J is also what's required for a 3-board karate break, though that's a lower velocity strike.)
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Cs. Norbert
Location: Romania Joined: 21 Aug 2015
Posts: 27
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| Posted: Wed 23 Sep, 2015 4:23 am Post subject: |
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| Timo Nieminen wrote: | While the arrow alone is designed to penetrate (and a penetrating arrow will behave very differently from a plastic bullet), the arrow + mail + padding is designed to not penetrate (from the perspective of the target). As long as the impact is spread over 1"x1" by the armour and padding, why would there be a large difference? (Look at Bane's photos - for the non-penetrating arrows, how wide is the deformation?)
A plastic bullet is typically a little heavier than an English warbow arrow, and a little faster. To claim that it causes less deformation than an arrow that is stopped by mail + padding seems rather incredible. At the very least, that claim needs experimental support. Claiming that a leftover 60-75J or so (after deforming and moving the mail and compressing the padding) is likely to cause serious injury or kill when 250J of plastic bullet usually doesn't just looks like highly partisan wishful thinking.
Rejecting data available on hitting humans with projectiles of similar weight and speed as arrows in favour of data on shooting animals and tissue simulants with bullets of 1/10 to 1/5 of the mass, and 5 to 10 times the speed also looks dubious.
150-250J of blunt projectile works quite well for stopping humans. Contemporary accounts like "When he was drawing (i.e. shooting) at the besiegers his shooting was registered by everyone because he either struck and seriously wounded those who were unarmoured, or put to flight those whom he aimed at with the arrows he shot, astounded - battered but not wounded since they were armoured." make sense (see http://myArmoury.com/talk/viewtopic.php?p=297673 for discussion of this passage).
Given the bad PR when people are killed by less-than-lethal munitions, even if not very often, if lower energies worked reliably for stopping people, they would be used. The 150J beanbag round looks like an effective minimum (the higher energy rounds are designed for longer ranges, and there are higher energy beanbag rounds designed for longer ranges; the 150J beanbag is used at short ranges (sometimes just a few metres).
(150J is also what's required for a 3-board karate break, though that's a lower velocity strike.) |
The plastic bullet has a rounded (or almost flat surface) shape in front, thus the energy from the the bullet is spread to a larger area . If shot in the chest, it can kill because of the shock and compression of the lungs.It is not designed for penetration, it's stopping power comes from the external injuries along with the shock wave that is transmitted (like a fist punch which can produce internal damage if powerful enough). In Bane's testing with mail and padding the deformation is very deep and it has a cone shape (the wide deformation is at the rear), because the arrow head doesn't compress, and it's shape permits a deeper deformation because of the small contact area. IF the mail is flexible enough, it folds (along with the padding) closely to the shape of the head, resulting a cone shape with a dull tip (that is much smaller than the plastic bullet) and a bigger base diameter! To have the same base indentation diameter as the plastic bullet in the same medium, a diamond or cone shaped projectile will have a deeper indentation! Both projectiles can produce similar effects, in 2 different ways: one can cause internal injuries because of the powerful shock wave, the other can cause internal injuries because of high deformations with a smaller shock! Imagine the damage done by a powerful boxer that strikes a clean hit at the liver, now consider that the target is wearing a normal leather jacket with thicker padding, but now the the one landing a hit is not as powerful as the boxer, but uses a stick with a rounded head (or a broomstick), the force needed to achieve similar effects is not the same!
Having a mail with denser waves and small ring diameter results in less flexible mail, that doesn't allow deep indentations before is breaks (it either stops the arrow or it fails by breaking, before 2" of indentation can be produced after the padding) This would offer the best protection along with light-medium padding. Suppose that we have a mail that is not that dense and it allows enough flexibility to cause deep deformations before breaking. To have a chance of stopping an arrow that has over 120J, you need a thick jacket (maybe the one from bane's testing is enough -15 layers of linen with one of deer skin). My theory (I cannot prove this without testing) is that, the arrow will most likely break the mail, but it might be stopped before the last few layers of linen are penetrated, if this is the case, the deformation depth should be close to 2"!
| Quote: | | Claiming that a leftover 60-75J or so (after deforming and moving the mail and compressing the padding) is likely to cause serious injury or kill when 250J of plastic bullet usually doesn't just looks like highly partisan wishful thinking. |
If the contact surface of the projectile doesn't have a shape that permits deep penetrations, then you need more energy to have similar damage [consider the shape and area of the boxer's fists and the high ke energy that the boxer is able to generate (much more then double of the plastic bullets) by moving a good part of he's body mass along with the fist].
| Quote: | | Rejecting data available on hitting humans with projectiles of similar weight and speed as arrows in favour of data on shooting animals and tissue simulants with bullets of 1/10 to 1/5 of the mass, and 5 to 10 times the speed also looks dubious. |
I'm not rejecting that data, I'm just considering that, the body armor penetration tests have more similarities in this context!
| Quote: | | (150J is also what's required for a 3-board karate break, though that's a lower velocity strike. |
Karate punches can generate more than 150J if more body mass is put in the strike, boxers generate even more ke, but that doesn't mean that they can kill on every strike!
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Timo Nieminen
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| Posted: Wed 23 Sep, 2015 3:53 pm Post subject: |
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| Cs. Norbert wrote: | The plastic bullet has a rounded (or almost flat surface) shape in front, thus the energy from the the bullet is spread to a larger area . If shot in the chest, it can kill because of the shock and compression of the lungs.
It is not designed for penetration, it's stopping power comes from the external injuries along with the shock wave that is transmitted (like a fist punch which can produce internal damage if powerful enough). |
Can kill, but is very unlikely to kill. Similar mass and speed, and momentum, and energy compared to an arrow. For a typical plastic bullet, more mass, more speed, more energy, and more momentum, but even with over 200J, it doesn't usually kill.
| Cs. Norbert wrote: | | IF the mail is flexible enough, it folds (along with the padding) closely to the shape of the head, resulting a cone shape with a dull tip (that is much smaller than the plastic bullet) and a bigger base diameter! |
Trying it with heavy mail and thin gambeson, I get a fairly round shape, about 35mm across. This is a static test, not shooting the armour. To get a pointy cone, you'd need to almost penetratre the gambeson (as you describe below). If it doesn't penetrate, you've got a minimum of one ring diameter and two thickness of padding, and the thickness of the head.
| Cs. Norbert wrote: | Having a mail with denser waves and small ring diameter results in less flexible mail, that doesn't allow deep indentations before is breaks (it either stops the arrow or it fails by breaking, before 2" of indentation can be produced after the padding) This would offer the best protection along with light-medium padding. Suppose that we have a mail that is not that dense and it allows enough flexibility to cause deep deformations before breaking. To have a chance of stopping an arrow that has over 120J, you need a thick jacket (maybe the one from bane's testing is enough -15 layers of linen with one of deer skin). My theory (I cannot prove this without testing) is that, the arrow will most likely break the mail, but it might be stopped before the last few layers of linen are penetrated, if this is the case, the deformation depth should be close to 2"!
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If the armour is sufficiently light, the arrow will go through. In that case, blunt trauma is a non-issue. I don't think it's necessary to consider lightweight mail and padding. If a typical arrow goes through almost all of it, that's lightweight. Better to consider the kind of mail + padding you'd wear to keep out 150J arrows reliably. Perhaps the commonly used three layers: padding under the mail, and another layer of textile armour over the mail.
"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Cs. Norbert
Location: Romania Joined: 21 Aug 2015
Posts: 27
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| Posted: Wed 23 Sep, 2015 10:08 pm Post subject: |
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| Timo Nieminen wrote: | | Cs. Norbert wrote: | The plastic bullet has a rounded (or almost flat surface) shape in front, thus the energy from the the bullet is spread to a larger area . If shot in the chest, it can kill because of the shock and compression of the lungs.
It is not designed for penetration, it's stopping power comes from the external injuries along with the shock wave that is transmitted (like a fist punch which can produce internal damage if powerful enough). |
Can kill, but is very unlikely to kill. Similar mass and speed, and momentum, and energy compared to an arrow. For a typical plastic bullet, more mass, more speed, more energy, and more momentum, but even with over 200J, it doesn't usually kill.
| Cs. Norbert wrote: | | IF the mail is flexible enough, it folds (along with the padding) closely to the shape of the head, resulting a cone shape with a dull tip (that is much smaller than the plastic bullet) and a bigger base diameter! |
Trying it with heavy mail and thin gambeson, I get a fairly round shape, about 35mm across. This is a static test, not shooting the armour. To get a pointy cone, you'd need to almost penetratre the gambeson (as you describe below). If it doesn't penetrate, you've got a minimum of one ring diameter and two thickness of padding, and the thickness of the head.
| Cs. Norbert wrote: | Having a mail with denser waves and small ring diameter results in less flexible mail, that doesn't allow deep indentations before is breaks (it either stops the arrow or it fails by breaking, before 2" of indentation can be produced after the padding) This would offer the best protection along with light-medium padding. Suppose that we have a mail that is not that dense and it allows enough flexibility to cause deep deformations before breaking. To have a chance of stopping an arrow that has over 120J, you need a thick jacket (maybe the one from bane's testing is enough -15 layers of linen with one of deer skin). My theory (I cannot prove this without testing) is that, the arrow will most likely break the mail, but it might be stopped before the last few layers of linen are penetrated, if this is the case, the deformation depth should be close to 2"!
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If the armour is sufficiently light, the arrow will go through. In that case, blunt trauma is a non-issue. I don't think it's necessary to consider lightweight mail and padding. If a typical arrow goes through almost all of it, that's lightweight. Better to consider the kind of mail + padding you'd wear to keep out 150J arrows reliably. Perhaps the commonly used three layers: padding under the mail, and another layer of textile armour over the mail. |
I think we are both saying the same thing but in different ways! If we want to stop an arrow of 150J (or lower) the most reliable method would be (best would be plate, but we need to assume that we can only get mail) a heavy mail with normal padding, in this scenario the arrow would be stopped or if it goes trough the mail then we don't need worry about blunt trauma, because, most probably the arrow will penetrate the flesh (if the target was lucky enough to just penetrate the mail, but not the padding, the blunt trauma and the deformations will be minimum)! The very heavy mail that would be needed to stop that arrow would be similar to those from Dan's attachments, so we are not speaking of highly flexible mail anymore!
As Dan stated, those arrows could be stopped by 2 lighter mails, but event with this setup we are not talking of mail that is flexible enough to allow deep deformations! A third scenario would be a lighter mail with a very thick jacket (like the one with 16 layers that Bane used). In this scenario, the arrow could (depending on the mail type) penetrate the mail and be stopped by the jack, or (if flexible enough) the mail could survive. In Bane's testing, the jack coat wasn't penetrated by the short bodkin, but the deformations were deep (1.4" - page 11, figure 12)! Considering that we have more then double the energy from Bane's testings , the arrow could cause deformation depths up to 2" even if mail survives, and if mail is penetrated (some layers of jack might also be penetrated) the probability of 2" deformations, is increased!
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Cs. Norbert
Location: Romania Joined: 21 Aug 2015
Posts: 27
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| Posted: Wed 23 Sep, 2015 10:13 pm Post subject: |
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I will be out of the country, so I don't know when will I be able to reply!
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Lafayette C Curtis
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| Posted: Wed 07 Oct, 2015 11:00 am Post subject: |
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We should be really, really careful about taking the draw-weights cited in Chinese military examinations at face value. There's a fair amount of evidence that these examinations were done with special "strength bows" that weren't meant for shooting, and also that they were performed with a different draw (completely grasping the string in the fist) that would have been impractical for actual shooting. The result is that archers could handle a greater draw weight with the examination bow than they could actually handle in everyday military service, and the draw-weights of the bows they really shot with would have been somewhat lower than the strength bow they qualified with.
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Dan Howard
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| Posted: Wed 07 Oct, 2015 1:49 pm Post subject: |
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| Lafayette C Curtis wrote: | | We should be really, really careful about taking the draw-weights cited in Chinese military examinations at face value. There's a fair amount of evidence that these examinations were done with special "strength bows" that weren't meant for shooting, and also that they were performed with a different draw (completely grasping the string in the fist) that would have been impractical for actual shooting. The result is that archers could handle a greater draw weight with the examination bow than they could actually handle in everyday military service, and the draw-weights of the bows they really shot with would have been somewhat lower than the strength bow they qualified with. |
I'd like to read more about this. Do you have any cites?
Author: Bronze Age Military Equipment, Pen and Sword Books
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