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Post by Cybermortis on Nov 2, 2014 19:01:04 GMT
Bows are not THAT inaccurate, especially modern bows firing at a target at close range. Any inaccuracy is usually down to the archer not the bow itself. In this case a bow that is in a secured rig can be sighted in just as easily as a gun at these ranges - and indoors wind is simply not a factor so shots will be consistent.
The safety aspect of firing in a contained area is less about a bow-rig totally missing the target and backstop due to inaccuracy, and more because there is no way to predict what the arrow is going to do when it hits the rope - especially if it doesn't cut the rope. This risk would apply regardless of how the arrow is fired, as it has nothing what-so-ever to do with the firing system but with the arrow itself.
Why you think that firing through a tube would be in any shape or form better than just using an arrow rest on a bow is beyond me. Arrow rests are, well, designed to keep arrows in place without affecting accuracy. Why try reinventing a system that already works with a launch system that would be needlessly complex and wouldn't remove the need for the bow rig?
Adjusting velocity is just as simple with a bow as with an air gun, probably simpler in fact because a fair amount of the force in an air gun is going to be lost as to passes around the arrow which would make comparing the velocity of an arrow in an air gun to that of a bow difficult at best, and more likely impossible in practical (MB) terms.
All they need is a length of rope that has a quick release 'hand' on the end and has a force meter attached to it. Pull on the rope until you reach the required draw weight, then release the 'hand'. (In other words duplicating how bows are really fired). You can do this to vary the velocity up to the maximum draw weight of the bow. In this case because we are talking about medieval bows they'll need a VERY powerful bow - probably something in the 150lbs DW range as this seems to have been roughly the average for an English Longbow.
As far as the rope goes, given the dating of the myth we'd probably be talking about hemp rope with thicknesses of half an inch to ten inches. This would probably cover everything from ropes used on grapples to the thickness of rigging during this period. For bench testing the rope could be simply tensioned between two clamps, which would allow them to reset and test quickly to see if A; An arrow and cut a rope, B; How powerful the bow would have to be and C; At what thickness an arrow would have no effect at all.
Then they can move on to doing a 'real world' test using the best types of arrow, best thicknesses of rope (or up to the thickness at which arrows are not doing anything at all) and the best strength of bow.
All of this could be done in three days - one to design and built the rig. One for indoor testing and one for the outdoor testing. They could expand this to four or maybe five days if they feel it is worthwhile seeing if they could design their own rope-cutting arrow. In which case add two days for them to review the data from the earlier tests, come up with a design and build it. (And you just KNOW Jamie is going to cheat by making an arrow with a six inch wide cutting edge and a bow that is mounted on a cart).
Start messing around with air cannons and you can add at least two more days to that - to say nothing of people (rightly) pointing out that an arrow fired out of a gun will not behave the same way as an arrow fired out of a bow. Making the airgun tests a total waste of time unless they also do bench testing with...errm...a real bow.
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Post by the light works on Nov 2, 2014 23:48:47 GMT
Bows are not THAT inaccurate, especially modern bows firing at a target at close range. Any inaccuracy is usually down to the archer not the bow itself. In this case a bow that is in a secured rig can be sighted in just as easily as a gun at these ranges - and indoors wind is simply not a factor so shots will be consistent. The safety aspect of firing in a contained area is less about a bow-rig totally missing the target and backstop due to inaccuracy, and more because there is no way to predict what the arrow is going to do when it hits the rope - especially if it doesn't cut the rope. This risk would apply regardless of how the arrow is fired, as it has nothing what-so-ever to do with the firing system but with the arrow itself. Why you think that firing through a tube would be in any shape or form better than just using an arrow rest on a bow is beyond me. Arrow rests are, well, designed to keep arrows in place without affecting accuracy. Why try reinventing a system that already works with a launch system that would be needlessly complex and wouldn't remove the need for the bow rig? Adjusting velocity is just as simple with a bow as with an air gun, probably simpler in fact because a fair amount of the force in an air gun is going to be lost as to passes around the arrow which would make comparing the velocity of an arrow in an air gun to that of a bow difficult at best, and more likely impossible in practical (MB) terms. All they need is a length of rope that has a quick release 'hand' on the end and has a force meter attached to it. Pull on the rope until you reach the required draw weight, then release the 'hand'. (In other words duplicating how bows are really fired). You can do this to vary the velocity up to the maximum draw weight of the bow. In this case because we are talking about medieval bows they'll need a VERY powerful bow - probably something in the 150lbs DW range as this seems to have been roughly the average for an English Longbow. As far as the rope goes, given the dating of the myth we'd probably be talking about hemp rope with thicknesses of half an inch to ten inches. This would probably cover everything from ropes used on grapples to the thickness of rigging during this period. For bench testing the rope could be simply tensioned between two clamps, which would allow them to reset and test quickly to see if A; An arrow and cut a rope, B; How powerful the bow would have to be and C; At what thickness an arrow would have no effect at all. Then they can move on to doing a 'real world' test using the best types of arrow, best thicknesses of rope (or up to the thickness at which arrows are not doing anything at all) and the best strength of bow. All of this could be done in three days - one to design and built the rig. One for indoor testing and one for the outdoor testing. They could expand this to four or maybe five days if they feel it is worthwhile seeing if they could design their own rope-cutting arrow. In which case add two days for them to review the data from the earlier tests, come up with a design and build it. (And you just KNOW Jamie is going to cheat by making an arrow with a six inch wide cutting edge and a bow that is mounted on a cart). Start messing around with air cannons and you can add at least two more days to that - to say nothing of people (rightly) pointing out that an arrow fired out of a gun will not behave the same way as an arrow fired out of a bow. Making the airgun tests a total waste of time unless they also do bench testing with...errm...a real bow. arrows travel much slower than bullets so differences in velocity have a lot more affect on drop. I can predict exactly what an arrow fired through a tube will do if it fails to cut the rope - it will stay in the tube. using a rope to draw the bow is, as I have already said, problematic, because any rig you make to trigger the release (not some kind of hand - an archery release, because as long as you are using things picked up off a shelf you might as well use something designed specifically to draw and release a bowstring) will tug on the string and impart a random element to the shot. you forget that the biggest component of being an archer is making your draw, hold, and release absolutely uniform every single shot. drawing to a particular tension is also problematic, because there is no linear curve there - and it is largely dependent on the bow. I've drawn a recurve that draws at 50 pounds right up until you hit overdraw length when it "stacks" rapidly; and I have drawn other bows that start stacking almost immediately, but stack much more slowly. because of this, length of draw is also not a good linear measurement. as for the target rope, as SD suggests, the sky is pretty much the limit - I'd say a weight tensioned rope is a pretty good given - but length will also make a difference on how much deflection is possible. - and hitting at a point where the rope is against something will probably make a difference so I guess - have fun buying out a sporting goods store to get enough different bows with different draw weights to get a good read for what your velocity needs to be to cut the rope; and particularly shopping for your 150# draw longbow. then the day building a rig to hold and fire multiple different bows; because using the bow to test, it might be that the bow you are using doesn't have the right velocity to cut the rope, and maybe a different bow will do it. |
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Post by Cybermortis on Nov 3, 2014 2:09:44 GMT
You are not going to see any significant drop from an arrow over the ranges at which it would be practical to run bench tests.
If all you want to do is to see how much force is needed to cut a rope without using a bow you'd probably be better off using a piston with the arrow head screwed to the end. Of course the problem is, again, that this is a lot of time and effort for a 'one shot' test - it would be more or less useless for testing other types of trick arrow and tell them nothing about how an arrow acts when in flight.
Keep in mind that this myth on its own is not enough to fill an entire segment, so it would most likely to attached to a number of related bow and arrow myths - trick arrows in general spring to mind here. Again, if they are going to do trick arrows it would be a natural step for them to consider trying to design their own. Be that a 'Boxing Glove' arrow as seen by the character Green Arrow, or a better rope cutting arrow. In order to do that they HAVE to know how arrows act in flight in order to make a reasonable prediction as to what they could get away with.
150lb bows ARE available, but seem to be custom builds (usually it seems from historical groups and bowmakers) mainly because not that many people are capable of using a bow that strong.
MB already created a bow-firing rig, although it probably isn't around anymore. Going off memory this was a very simple rig, and the only difference between what I had in mind and what they built is the addition of a gage to let them see how much draw weight they have on the bow. As I recall the bow used in that testing belonged to Tory, who had no concerns about the team wrecking his bow. I'd guess that the local archery club in SF would be able to tell MB where to get a 150lb bow, or put them in touch with someone who might be willing to loan them one. (Probably better to get in touch with a bowmaker as they are more likely to have more than one bow available, plus they might also be able to provide the arrows)
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Post by silverdragon on Nov 3, 2014 8:42:19 GMT
I think its getting to technical.... KISS principal, the bow is accurate "Enough", plus if it isnt that accurate in the first place, if 100 shots wont hit the target that accurate, then thats proof enough that a once-in-a-lifetime shot is not that plausible anyway......
Target range, 100 yds is about the extreme for taking that kind of shot, its not as if you would want to be anywhere you could get caught, and any closer, wouldnt it just be easier to walk up and cut it anyway.
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Post by Cybermortis on Nov 3, 2014 11:46:15 GMT
Bench testing is much more likely to be 10-30 feet at most. They don't really have the room to do more than than in the shop.
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Post by OziRiS on Nov 3, 2014 11:46:17 GMT
I have to say, I get what TLW is saying about starting out with seeing if an arrowhead can even cut a rope to begin with. There's a very real possibility that it's not going to happen at any draw weight or with any arrowhead, so gettting a bunch of different bows and spending days firing arrows at ropes that may give no real results seems like a waste to me.
Cyber's idea of a piston driving the arrowhead into a length of rope may be thebest idea yet, though. I was thinking the same thing while going through the thread. If the arrowhead can't make it through the rope to begin with, even though the rope is held taught against a hard surface and the arrowhead hits it dead on with superhuman speed, what's the point in proceeding from there?
A piston powered arrow "shooter" should be a pretty easy build. I'm sure they have something laying around that could be easily modified for the job.
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Post by Cybermortis on Nov 3, 2014 12:16:38 GMT
You don't need a 'bunch of bows', you just need one since the only part of the bow that will affect the cutting power of an arrow is the strength of the bow.
Of the three main type of bow, longbow, recurve and compound a Longbow would be the best choice. Recurves top out at draw weights of 80lbs, which is at the lower range for a medieval warbow. Compound bows use pulleys, which means that the actual amount of force produced is as much a result of the pulley design as anything else and would make it difficult to calculate how strong a more traditional bow would need to be. Its not impossible, but it does seem an unnecessary step to have to go through when the simplest way is to just directly measure the draw weight when firing.
A long bow in this context is ideal. They can just measure the draw weight when they fire, Longbows can be given much draw weights that recurves and as I keep trying to point out you don't have to fire them at full draw - a 150 lb long bow can be fired at 20/40/60/80/100/120lbs ect as long as you know how much pressure is on the string. As Light noted there is not always a direct relationship between how far back the string is pulled and the amount of energy it will release. So you have to measure the weight on the string not how far the string is pulled back.
If they can't get any results using a bow they can move onto using a different rig to see if it is possible at all. Depending on who you ask the upper range for the English Longbow was some 200lbs - which is well beyond what a modern archer could use. Even if MB could find a bow that powerful they would probably be wary of firing it indoors, which would make other options desirable should they need to look at that kind of power.
Besides, for all we know it might turn out that you don't need that powerful a bow to cut a rope. So it would be somewhat wasteful to design and build a rig they then don't need to use.
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Post by OziRiS on Nov 3, 2014 15:12:34 GMT
And as TLW and I are pointing out, this is just a proof of concept test. Something they've done for hundreds of other myths before.
The point is to test if, regardless of type of bow, strength of the archer, accuracy, arrow flight dynamics and so on and so forth, can an arrowhead even cut a rope?
It seems silly to me to procure a bow (possibly even a custom built one), procure or produce different types of arrows, hang ropes with or without weights and spend an entire day shooting arrows at them, only to come to the conclusion AFTERWARDS that maybe you should see if an arrow could even cut a rope under the best possible conditions to begin with, when it's so much easier to just procure/produce one of each type of arrowhead you're going to use for the test and see which ones fare best before you start tossing money and time at everything else.
And this is not a difficult build. Get a large sheet of plywood, lay it down on the floor, get a piston of some sort where you can vary the speed, weld four struts to it, so you have a stand and bolt it to the plywood, piston facing down. Weld something to the end of the piston to hold the arrowhead, put the rope on the plywood directly under the piston and start testing. Assuming they have a variable speed piston, this build shouldn't take more than a couple of hours tops, so I don't really see the problem.
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Post by the light works on Nov 3, 2014 15:16:52 GMT
You don't need a 'bunch of bows', you just need one since the only part of the bow that will affect the cutting power of an arrow is the strength of the bow. Of the three main type of bow, longbow, recurve and compound a Longbow would be the best choice. Recurves top out at draw weights of 80lbs, which is at the lower range for a medieval warbow. Compound bows use pulleys, which means that the actual amount of force produced is as much a result of the pulley design as anything else and would make it difficult to calculate how strong a more traditional bow would need to be. Its not impossible, but it does seem an unnecessary step to have to go through when the simplest way is to just directly measure the draw weight when firing. A long bow in this context is ideal. They can just measure the draw weight when they fire, Longbows can be given much draw weights that recurves and as I keep trying to point out you don't have to fire them at full draw - a 150 lb long bow can be fired at 20/40/60/80/100/120lbs ect as long as you know how much pressure is on the string. As Light noted there is not always a direct relationship between how far back the string is pulled and the amount of energy it will release. So you have to measure the weight on the string not how far the string is pulled back. If they can't get any results using a bow they can move onto using a different rig to see if it is possible at all. Depending on who you ask the upper range for the English Longbow was some 200lbs - which is well beyond what a modern archer could use. Even if MB could find a bow that powerful they would probably be wary of firing it indoors, which would make other options desirable should they need to look at that kind of power. Besides, for all we know it might turn out that you don't need that powerful a bow to cut a rope. So it would be somewhat wasteful to design and build a rig they then don't need to use. I also pointed out that there is no linear relationship between how much tension there is on the string and the "muzzle velocity" short drawing a bow robs velocity at WAY more than a linear relationship; especially if you are doing it by weight. the piston idea is WAY better for adjusting velocity and weight. as your working length only needs to be the length of the rig plus enough that the piston is not still driving the arrow on impact. |
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Post by WhutScreenName on Nov 3, 2014 18:34:04 GMT
Sounds to me like everyone agrees this is a myth worth testing. The catch so far, has been on the method. I don't know about anyone else, but I feel both sides have thoroughly explained why their method should be used and it would be up to the MB's to decide how if they picked this up. Let's see if we can expand on the myth more, or maybe find some other bow myths?
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Post by the light works on Nov 4, 2014 15:19:59 GMT
how about the myth that "bowandarrow" is all one word? [/snark]
I've seen a few clips of people shooting arrows rapid fire, and they all walk while they are doing it. it left me wondering if the walking is a part of the mechanics of it, or if they could shoot just as rapidly standing still.
there is also the myth of a hero spinning a staff or similar weapon to block arrows - this would be fairly simple to test using a variable speed motor. (note - this is not a rehash of arrow catching - just whether it is humanly possible to (continuously) spin an object fast enough to deflect arrows shot through the arc)
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Post by WhutScreenName on Nov 4, 2014 17:13:27 GMT
there is also the myth of a hero spinning a staff or similar weapon to block arrows - this would be fairly simple to test using a variable speed motor. (note - this is not a rehash of arrow catching - just whether it is humanly possible to (continuously) spin an object fast enough to deflect arrows shot through the arc) Ohh, I like that one! |
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Post by the light works on Nov 4, 2014 17:18:09 GMT
there is also the myth of a hero spinning a staff or similar weapon to block arrows - this would be fairly simple to test using a variable speed motor. (note - this is not a rehash of arrow catching - just whether it is humanly possible to (continuously) spin an object fast enough to deflect arrows shot through the arc) Ohh, I like that one! it bordered on PTD on the old boards, which makes it a contender for ratings. |
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Post by Cybermortis on Nov 4, 2014 19:19:45 GMT
They could add blocking/deflecting arrows with a sword as well, as that was done on Arrow. (Meaning they might be able to use a clip from the series as a basis for the test).
Dry firing a bow will damage/destroy it; They just need a rig that can pull/push the string back to something close to full draw and release it repeatedly. Maybe a short pole with a strong spring attached to a wheel that can rotate, catch the string to push it back and then spring out of the way when the bow is at full draw. And snap back into position after the string is released so it can catch the string on the next rotation. This might not need to be a particually complex build, and could be left running without supervision in a secure area; So that if the bow does shatter no one is at risk. They could place a foam cutout where the archer would be standing to catch any fragments and work out how serious any injuries might be. (Balistics gel might not be an option as the rig might have to be kept running for some time while under hot lights for filming). They could run these tests with different types of (cheap*) bow made from different materials (Off the top of my head metal, wood and carbon fibre) to see which might be more dangerous. Since this is a 'set up and leave it running' type of test time considerations may be fairly minor, if they are doing a lot of other stuff in the shop at the same time.
(*Off the top of my head the costs would be around £25 for a cheap adult carbon fibre bow and £50-60 for a compound or recurve bow - the latter with metal limbs. Not entirely sure what wooden bows would cost, but we'd probably be looking at a total of about £200 for three new bows. They'd need to buy new as older bows might have suffered damage or abuse (or been dry fired) at the hands of prior owners. The rig itself could probably be constructed from materials already in the shop, meaning they probably wouldn't need to buy anything for it.)
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Post by OziRiS on Nov 4, 2014 19:22:35 GMT
there is also the myth of a hero spinning a staff or similar weapon to block arrows - this would be fairly simple to test using a variable speed motor. (note - this is not a rehash of arrow catching - just whether it is humanly possible to (continuously) spin an object fast enough to deflect arrows shot through the arc) Ohh, I like that one! I'd forgotten all about that one! Good catch! I've always thought it at least couldn't be done consistently, so the question might not be, "can you ward off all arrows like that?", but more, "is there a snowman's chance in Hades that it'll ward off any at all?" After all, if you knew there was even the slightest chance that it could deflect one or more arrows and your only option at this point was making a move to stay alive, wouldn't you at least try? |
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Post by WhutScreenName on Nov 4, 2014 19:40:00 GMT
Not sure exactly sure what 'myth' could come from this, but having shot a lot of bow, I've had the string hit my arm a few times, which is anything but pleasant. Would there be something to breaking an arm if it was held improperly and hit just right? Just thinking out loud (as far as internet typing is 'out loud' LOL)  |
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Post by memeengine on Nov 4, 2014 20:46:45 GMT
there is also the myth of a hero spinning a staff or similar weapon to block arrows - this would be fairly simple to test using a variable speed motor. (note - this is not a rehash of arrow catching - just whether it is humanly possible to (continuously) spin an object fast enough to deflect arrows shot through the arc) I seem to remember someone doing the math to calculate how fast the staff would have to be spinning for a given arrow length and velocity. I can't remember the exact numbers but for illustration, let's say the arrow is 0.75 metre long and travelling at 50 m/s, then the length of the arrow will have passed through a given point in 0.015 seconds. Let's assume that the staff being used is of negligible width compared to the length of the arrow and is being rotated around its centre. So in order to be sure to hit the arrow, each half of the staff would need to sweep through half a rotation in 0.015 seconds. Therefore a full rotation would take a 0.03 seconds, which is about 2,000 rpm. Obviously, more realistic numbers for the arrow length and velocity will give a more accurate rotation rate. |
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Post by the light works on Nov 5, 2014 0:54:00 GMT
for the dry fire test, if you were going to use a bow for other tests, the same rig could be built for both - just set for single shot or repeating.
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Post by Cybermortis on Nov 5, 2014 1:08:10 GMT
The rig I discribed might not be suitable for actually firing an arrow, as it would bend the string to the side. (I'm viewing it as something that is off to one side of the bow not behind it). A rig for firing the bow with an arrow would probably be better if it is pulling the string from behind, and could be designed to pull around an arrow - which might be a little to figity to do with the 'stick' idea. (It would be possible I guess, but runs the risk of catching the fletching as it rotates into position or pushing the string to the side as it releases).
A question of design, simplicity and how much time they would have to mess around with things. The base rig of course could remain the same, since that is basically just something to hold the bow in place. But they may opt for two simpler pulling rigs rather than one somewhat more complex one - and of course two pulling rigs allows them to have Jamie working on one and Adam on the other. Something that might make the episode more interesting to watch and help pad things out a little.
Both would be worth them considering though. Maybe run the dry firing tests first to see how the rig works and decide if it could be used for firing arrows or modified to do so without major problems such as taking longer than just building something else for that.
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Post by the light works on Nov 5, 2014 1:28:37 GMT
The rig I discribed might not be suitable for actually firing an arrow, as it would bend the string to the side. (I'm viewing it as something that is off to one side of the bow not behind it). A rig for firing the bow with an arrow would probably be better if it is pulling the string from behind, and could be designed to pull around an arrow - which might be a little to figity to do with the 'stick' idea. (It would be possible I guess, but runs the risk of catching the fletching as it rotates into position or pushing the string to the side as it releases). A question of design, simplicity and how much time they would have to mess around with things. The base rig of course could remain the same, since that is basically just something to hold the bow in place. But they may opt for two simpler pulling rigs rather than one somewhat more complex one - and of course two pulling rigs allows them to have Jamie working on one and Adam on the other. Something that might make the episode more interesting to watch and help pad things out a little. Both would be worth them considering though. Maybe run the dry firing tests first to see how the rig works and decide if it could be used for firing arrows or modified to do so without major problems such as taking longer than just building something else for that. so you're suggesting they make a rig for testing dry firing that does not have proper drawing and firing mechanics? of course, the next challenge in the dry firing test - is you have to test the same bow the same number of repetitions - with arrows. otherwise how do you know that wasn't the failure point of that bow? |
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