Primitive Archer
Main Discussion Area => Bows => Topic started by: Badger on January 01, 2010, 10:12:48 pm
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I can't believe how time flys. I went from being a bow making machine t not making any bows at all. Just suddenly stopped. I still pull some of the old bows out of the garage and rework them here and there. I think I just ran out of things to try. I think mentaly I am gearing up for my next project I plan to start next year. I won't go into detail but it will be a giant flight bow, maybe 50 ft long. This is my retirement project, plan to have about a 20ft draw and rig it to shoot 12 ft long poles. This year I plan to go down south and find the hickory trees I will need, figure I will build it in the desert somewhere very dry. Hoping for a 1/2 mile long shot. Steve
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If you had a really big treestand you could take it hunting. I bet it would take out any animal on the North American continent. ;D
Chuck S.
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hell i would use that one on that cape/water buffalo hunt folks been talking about ;D
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Badger, I remember you were working on one from osage when I visited Pasadena. It happens. I don't make as many as I used to either. But workshop time is precious so enjoy it if you can and while you can. Happy New Year! Jawge
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I think sometimes going back to basics puts the fun back in it. What I enjoy most is just sitting out in the backyard on my shaving horse, endless supply of coffee and making shavings. End result is not all that important, I just enjoy seeing them make the 28" the first time. Put a few dozen arrows into a target and then grab another stave and start over. When the hobby started to grow into something a bit larger some of my passion for making bows went with it. I hope when I retire next year I can get that back. Steve
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I'm just finishing up a bow I'll post this week. But I am also starting to build a lapstrake boat. All new terminology and mostly new technique.
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Why a 50ft bow to shoot a 12ft spear??
That would be scaled to using a 9.7ft bow to shoot a 28 inch arrow.
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I agree Steve, as soon as it becomes work, well then its just work. I didn't make any bows for a month earlier this year, and it was a refreshing break. Today I had a bunch of fellow deranged hanglider pilots flight shooting my latest osage backed osage long bow in the local landing zone, and that was very motivating to watch.
On that 50' bow can I get the first ride? ;D I'm sure we have a few more Missouri trips left in us as well 8)
Rich
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az, I am going to draw the bow about 20ft, I will build it with an overdraw device, I want the arrow pretty light for more distance. Steve
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Steve I can definitely relate. I have an attention disorder and I seem to get bored easy. I'm amazed at how many bows that I have that are half done. After a while I get a mental block and want to try something new or nothing at all. ::)
Trying very hard right now to discipline myself and finish a few of them. ::)
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Steve I can definitely relate. I have an attention disorder and I seem to get bored easy. I'm amazed at how many bows that I have that are half done. After a while I get a mental block and want to try something new or nothing at all. ::)
Trying very hard right now to discipline myself and finish a few of them. ::)
me too
plus i always find my rock pile calling me since i started to knapp
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guys there is nothing wrong with not making a lot of bows for a while. I finished my last 2 christmas bows up two weeks ago and haven't touched a bow since. I bet most of you guys are like me with lots of hobbies and interests. I've re-aquainted myself with my guitars, straightened up my tools and work space, as well as a few honey do's. Oh i will back at it soon, but a break with help you find perspective. Badger i would love to see that giant bow!!! please post pics and video if you can.
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ahh...forgot about overdraw on flight bows
what would you use for tillering? a hand held belt sander or a chainsaw? lol
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Most likely for tillering I would make a taper jig and run it through a planer.The limbs will probably be like 3 bows side by side and joined at the tips and several places along the limbs. I am actually hoping a tv show picks it up to help off set the costs. One team would build the firing platform and release I would just concentrate on the bow.
Richard, we could launch your gliders with this thing!
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Sounds like a cool project. I wondered a few times about making a giant bow. I figured a laminate would be the way to go. I for one cant wait to see what you come up with. Just stand clear when playing with it. I imagine you would get more than a thump on the head from that one.
I'm like keenan and others. I start a bow and then get into something else. I was sure I was going to be making some snow shoes this winter but didnt start that yet. Been playing drums lately/making loud noise which is good fun for my A.D.D. brain ;D I look at the bows I'm working on a lot more than I actually work on them.
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Most likely for tillering I would make a taper jig and run it through a planer.The limbs will probably be like 3 bows side by side and joined at the tips and several places along the limbs. I am actually hoping a tv show picks it up to help off set the costs. One team would build the firing platform and release I would just concentrate on the bow.
Richard, we could launch your gliders with this thing!
man if that didnt give ya whip lash when ya launched nothing would.wouldnt want to be thefirst to try and get flight off of that
that would be so cool if you get a show to pick it up.something like ancient weapons or even modern marvels
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I hear what you are saying Steve. Sometimes the way things work out it makes it difficult to pick up a bow and get busy. Sometimes I don't want to build at all. Lately I have had a little motivation to build, but not to shoot. I haven't had any opportunity to hunt and it robs me of my desire.
I thought the 7 1/2' Osage bow I started was big. This sounds like an interesting project. Getting a permit to build it in the desert might be the hard part, unless you have access to private land.
George is all about safety, I wonder if he has a tillering tree you can use so you don't have to stand next to the monster while you are tillering. ;)
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I can't believe how time flys. I went from being a bow making machine t not making any bows at all. Just suddenly stopped. I still pull some of the old bows out of the garage and rework them here and there. I think I just ran out of things to try. I think mentaly I am gearing up for my next project I plan to start next year. I won't go into detail but it will be a giant flight bow, maybe 50 ft long. This is my retirement project, plan to have about a 20ft draw and rig it to shoot 12 ft long poles. This year I plan to go down south and find the hickory trees I will need, figure I will build it in the desert somewhere very dry. Hoping for a 1/2 mile long shot. Steve
I'm not the only one then, Steve. I manage maybe 2 bows a year, maybe. I marvel sometimes at the guys who churn out bow after bow, but each person is motivated by whatever motivates them, and while I wish I could be more productive and prolific, I need balance in my life that includes a lot of other things. Burning out on something tells me I need to walk away for a while.
One thing I noticed about myself is that I need a bow design that speaks to me very strongly. I'd be a much better bow maker if I kept busy making bows, perfecting techniques, eliminating things like excessive set, improving heat treating, etc, but the desire has to be there. Right now, I've manged to begin tillering a Sarnate bow over the past few days, a neolithic bow design I found on Paleoplanet. The other bows that are partially done I will get to one day, or not, but they don't touch that nerve I need to be interested in them.
The 50 foot bow sounds dangerous, so take care. I have this 4 hour tape of a Korean bowyer, and I understand that his attempt at building a giant court bow of some kind contributed to his death, but I am not sure of the details. It sounds more like a catapult then a bow you are thinking of making. The Greeks did built huge tension machines featuring a bow, but after a certain size, torsion springs were developed to realize greater and greater power for stone and arrow shooting machines, so there may be a limit to how big a bow can get. Some of the Da Vinci designs were enormous, but they were theoretical, and probably never built.
You may want to look into the pumkin' chuckers. http://www.punkinchunkin.com/ The big goal with them is to build a machine to fling a pumpkin 1 mile. It is an amazing culture of people, and some of the machines are based on bows, while others are something like trebochets, catapults, and other types of machines. I can introduce you to some of the folks, including Team Tormenta, a group based here in MA. I have a buddy who is invovled with them on some research projects. I'm sure they would recognize you from that TV show you appeared on, the Da Vinci show.
Probably you are busy with other projects, though. If you are creative, you will find outlets. I'm building a NW Trade Gun, making furniture, messing with slings, making atlatls, and developing historic shoots for my club. For this coming April I'm developing a historic timeline shoot, and am inviting ancient and medieval through WWII reenactors and living history people. Combined with a ISAC atlatls event and perhaps at least a few catapults, some top Native American living history guys and some early colonial living history guys, and a few small artillary pieces and crews, it ought to be a lot of fun. Almost all of it springs though from the skills I have developed with archery, so even if I dont pick up a draw knife for a while, the benefits of primtive bows keeps my life interesting.
Dane
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Badger, welcome back. I know what you're saying. I've found I can have a bow finished and shooting and look at it 6 months or 2 years later and see something that can be narrowed, piked, or even sanded a little smoother, and re-work that bow instead of starting the next. But its quality not quantity, right?
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Last year I did some work for the discovery channel, a series called " Doing DaVinci" one of my assignments was to build the giant bows that DaVinci had layed out in his plans for a large catapult. The bow was shaped in a 3/4 circle and worked as a torsion machine. I had to build it much thinner than da vinci had indicated or it would not have bent. The machine actually worked pretty well but on future builds they insisted that I build it just as DaVinci drew it. The last one had a bending section about 20 ft long and was too stiff to bend, I think we cranked about #12,000# on it and it was stiff as a rock as I knew it would be. I wanted to make it 2" thick and they insisted on 8" thick, go figure. My 50' bow will be scaled up from a 5ft bow in both width and thickness. Finding good lumber long enough will be the biggest challenge, I will need around 15,000# stored energy which shouldnt be too bad for a bow this size.
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Steve, what were the those guys like to work with? Especially the artist guy, can't recall his name but he came across as very volitile in the show.
There was another similar show, Surviving History, which featured these fabricators from Ohio making all kinds of torture devices and weapons, similar premise, though. They seemed like a much nicer crew of guys, had fun, and made some intersting toys.
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Last year I did some work for the discovery channel, a series called " Doing DaVinci" one of my assignments was to build the giant bows that DaVinci had layed out in his plans for a large catapult. The bow was shaped in a 3/4 circle and worked as a torsion machine. I had to build it much thinner than da vinci had indicated or it would not have bent. The machine actually worked pretty well but on future builds they insisted that I build it just as DaVinci drew it. The last one had a bending section about 20 ft long and was too stiff to bend, I think we cranked about #12,000# on it and it was stiff as a rock as I knew it would be. I wanted to make it 2" thick and they insisted on 8" thick, go figure. My 50' bow will be scaled up from a 5ft bow in both width and thickness. Finding good lumber long enough will be the biggest challenge, I will need around 15,000# stored energy which shouldnt be too bad for a bow this size.
What kind of wood do you think you're going to use?
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Very possibly white oak as straight grained white oak planks of 20 ft long are not too extremely difficult to find. Hickory will be my first choice if I can find a straight enough tree. Steve
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I have really slowed up in my buiding too. I originally wanted to build a bow or two that I could hunt with. I have built more than a couple hunting bows now so have slowed too.
But.... since I hurt my shoulder and have not been able to hunt this fall/winter I have been studying the Orcbow crossbow build- along and think that may be my next project. My Dr. has already said he would write a letter to the affect that I should qualify to hunt with a crossbow. Really have never had an interest in hunting with a crossbow but if that is the only way I'm able I will!!
Seems like one way or another I have to be making saw dust and wood chips in the shop too!! ;D
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Sounds like an awesome project, Badger! Keep us updated if you carry it out some day! You will be building it quite overbuilt, I suppose? A 50 foot near-destruction flight bow would be scary as heck!
My bow building interest has been re-newed by horn bows. I could recommend it to anyone :)
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Hey, Badger. I'm starting an osage bow this week. Lord willing. Last one done is a rotten egg! I mean done. Not just full draw. :) Jawge
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Jawge, when was it you were out here? That was my last bow I believe. Kvillo, I have been following your progress, they are tempting. Steve
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funny thinking.
You would be using and actual tillering TREE for this lol...not just a stick with some cuts in it...a 50Ft tree with steel rods inserted instead of wooden pegs lol
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Badger, build that huge bow and bring it to Burningman in late August. Shoot a FLAMING arrow every night for a week, with 50,000 people in the midst of "extreme self expression" watching over you. If you can "think it up" and do things such that no one is killed, at Burningman you can do it. I am certain you will return from that desert fest with a new outlook on everything, not just archery.
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David, one of the guys I am working with is one of the founders of burning man I believe. Flash Hopkins, cool guy. Steve
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Can't wait to see that one,I feel sure you will reach your gold.I don't build as many either,involved in a lot but not building them myself,I have a lot of other things that take away from my bow building time,it's all good,when working with your hand and learning new things. :)
Pappy
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I just read your post, and realized that its been over 2 years for me as well. (I used to post as Brokestick, but that account got deleted when the forum migrated and I wasn't paying attention) Seems like a succession of Army schools, broken down tanks and weapons when I wasn't in school, a move from CA to NY, and another deployment have all conspired to make me lose track of time. It seems, too, that I cycle through interests periodically. Unfortunately, the archery bug came back right before this deployment, but I had enough time to get my kids going on a couple store-bought bows, and a toy hickory bow (10# @ 20"), that was the last thing I made, for my youngest to learn on. I have 2 unfinished bows for my older boys from the same period, but by the time I get to finishing them, I'll have to make a bigger one for my oldest, and move those 2 down the line.
As for the siege engine you're planning (it would be a ballista), I believe medieval engineers went early on with rigid limbs and rope torsion devices, allowing them to adjust tension, and likely increasing the safety factor, as well as, decreasing the dimensions. check out this site: www.siege-engine.com
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OOPS, Guess I should have read the whole thread before I replied. This isn't your first foray into the siege engine realm. Best of luck.
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Jude, good point you made about using torsion devices to decrease demensions. Attempting to use wood to power these giants was one of DaVincis failings I believe. Wood will just not store the needed energy for the heavy projectiles they were using. I will probably need about 15,000# stored energy for this project I am working on. I could easily get this with a much smaller machine using torsion. Steve
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I remember when you mentioned you may slack off the bow building sometime back. Looks like you were true to your word! ;D
I haven't built a bow since late July when I built a hickory bow backed with Marine digital camo for my son who just graduated boot camp.
It shot like a house on fire but then just toward the stiff tip the limb stated to chrysal and give. Unless I try to patch it the stick has become a
wallhanger. I've been frustrated by how many bows I've made and so few of them I am really content with.
The all wood bow is still in my blood but presently I am finishing up a recurve form to give a fb lam bow a shot. At least, if this works out, I will have a bow
that will last a lifetime (?) to shoot while I perfect my self and sinew backed bow craft.
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Badger,
They once tried to build DaVinci's giant cross bow on TV. They kept breaking it. Of course, I don't think they followed what was a mediocre design in the first place. The "limbs" just weren't designed to bend as intended. The one time they got it to shoot, it was the biggest dog I ever saw.
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Another thing came to mind this morning. Things don't scale up or down as we think they should, because of the relationship of surface area to volume. if you make an object twice as big, it becomes 8 times as heavy. If you only look at it in 2 dimensions, like when you calculate beam strength, doubling thickness increases strength (ie: resistance to bending) is increased 4 times. Beams work the same as bow limbs; only the top and bottom surfaces do all the work, and the wood in the middle is there as a spacer. Increase the distance between the working surfaces, and the stiffness/strength increases by a factor of 2. If I was to double the size of a long bow, I believe it would work as follows: start with a 6' x 1" bend in the handle yew long bow 50# @ 28". Double the width=100# @ 28". Double the thickness=400# @ 28". Double the length, and the stiffness should drop by half to 200# @ 28", but should come back up to 400# @ 56". I'm not an engineer, so I'm a little scetchy on that last part. If you were to look at the bow as the limbs work, at full draw, each individual inch of wood is only bending half as much as it did in the shorter bow, but since it is 4 times as stiff, the back and belly are still under twice the stress from tension and compression. The question is, can the wood handle it? The answer is, probably not. To scale up a bow, it has to become proportionally wider and thinner than the original, and there's an upward limit on the practicality of that. I think my double size bow, if I wanted only to double the draw length and weight, would stay the same thickness as the original, and become a flat bow. Even if I were to only make it 1.5" wide, I would only make it 1.15 times as thick to make it 200# @ 56". It reminds me of when I made the toy bow for my little guy, It is only slightly shorter than an adult bow, slightly narrower, and about half as thick. I was surprized when it only came out to 10# @ 20", but the scaling factor had worked in the other direction for me. On the flip side, the little bow can be drawn to an adult draw length and has only taken 3/4" of set, under intense abuse.
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Steve, you may want to spend some time looking at this guy’s blog. http://www.wattsunique.com/blog/ He is building a late Roman iron-framed catapult. It is an in-swinger, which is still a fairly controversial subject within the catapult community. I personally think Watts is taking torsion engineering to heights rarely if even seen, including the work of the Englishman Alan Wilkins. Maybe his work can give you some insights into ancient artillery in general, and specialized engineering required for these kinds of projects. If you have worked at all with catapults, you will find it is a very different discipline from tension power.
Also, you probably should strongly consider getting the two-volume Eric Marsden works. They are out of print and somewhat rare, but you can find a set for 150 – 200 dollars from rare book sellers. While a bit out of date at this point (he died in the early 1970s, and wasn’t around to analyze the newer archeological finds such as Hatra), he gives some good insights into large bow-powered machines. The Greeks tended to call all tension machines gastrophets, even after ratchets had been incorporated in larger machines. Going from memory (books are at home right now), Marsden believed that torsion power eclipsed tension power (giant bows) probably because bows of that size had reached their zenith with the Greeks.
These large machines can be dangerous. There are written accounts of crew members being decapitated when a component fails. A 50’ bow I imagine can be a very dangerous thing to be around if catastrophic failure occurs.
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Dane, the tension powered machines are not as effective as the torsion models or even the dead weight models. This is part of what I want to demonstrate. Kind of a slap in the face to Da Vinci. The show was very disapointed when I pointed that these huge machines we were building would only be capable of shooting very light weights like maybe 2#. Da Vincis drawing indicate bending wood springs in many configurations. They have unworkable string angles and on the average are about 4 times thicker than would be even remotely possible. I spent the last couple of years building scale models and then modifying them to work. The torrsion machines in those days would throw buolders and dead horses. These tension machines if properly tuned could only throw small bombs and rocks at best up to about 10# for a 100 yard toss. When we shoot a bow and arrow the arrow is only about 1/1000 ratio of stored energy to payload for a speed of about 170 fps. I will be looking for about 400 fps so will be looking for a ratio of about 5,000/1. It will be almost dry fire. Most of my wood bows break when they hit the 280fps range using light arrows. I am also working on a sling shot using wood torsion springs and cables. I will post some photos tomorrow or later today. Wood can generate decent speeds but is not good for heavy payloads. Steve
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I am no Da Vinci scholar, but my feelings are that many, many of his designs are flights of fancy, or were done to satisfied patrons and gain employment. As a military weapons engineer, he was not particularly successful. Blasphemy eh?
I find it particularly interesting that the technologies developed in the Classical period were lost and bastardized / reinvented in the medieval and Renaissance periods, and were never particularly successful. Gunpowder of course was coming into its own when Da Vinci was drawing his drawings, and would doom earlier military technologies such as catapults, bows, and so on. A handgonne could be forged by a competent smith in a few hours, was very cheap, and does not need the years (lifetime) of training an archer does. A peasant or ordinary solider could be taught to load and fire a handgonne in a very short period of time, and his cost to the king about to start a campaign or war vs. a knight or bowman was very cost-effective. It also defeats the finest plate armor available. More efficient and cheaper ways to kill your enemy is what engineers were after, and that still continues.
I find it kind of funny and ironic that as you lay dying on some battlefield, your guts falling between your hands, you should blame some guy with a slide ruler for your demise.
This is a personal belief, but weapons design is mentally different than bow design, even the “war bows”. I keep in mind the sole purpose of these machines, which is efficient killing at a distance. Warfare is brutal and stark, and these machines only exist for war. A target for a bow can be a bale of hay for recreational shooting or a deer or elk, while a target for a catapult is always going to be a human being.
Bolts / arrows from these machines are quite a bit smaller than those needed for bows, as well. Maybe a giant bow needs a very small projectile, too. In that show Surviving History, they build a torsion catapult and did a good job, but they were shooting broomstick length spears, which made a lot of that work moot. The spears kind of sailed out of the machine and did interesting things trajectory-wise, if my memory serves me.
The guy Watts has been getting 350+ fps or so for his machine, which are impressive numbers, and point to what can be done with a really large machine. The big palitone stone throwing ballistas, most likely could be adapted to fire arrows, as well.
Dane
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Dane, I went to that web sight. He is doing some good research over there. Very interesting stuff. All the best machines in those days were built by backyard engineers with lots of common sense. About the same is true for the bows and arrows we build today. Steve
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It just occurred to me that the whole scale dilemma works in the opposite way for firearms and artillery. When you scale up a cartridge, you increase the powder charge by the same amount as the projectile weight, and the surface area to volume change works in your favor, when it comes to wind resistance. A 5.56mm NATO and a Cal, 0.50 BMG are nearly scale models of each other, and leave the muzzle at nearly the same velocity, but the 50 Cal travels twice as far. Bigger is better with artillery, until it gets too heavy to move around conveniently, but it is much easier to make small bows than to make large ones. The larger the bow, the fewer choices you have in suitable wood.
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Dane, I went to that web sight. He is doing some good research over there. Very interesting stuff. All the best machines in those days were built by backyard engineers with lots of common sense. About the same is true for the bows and arrows we build today. Steve
Glad you liked what was on the site. A nice guy too, lives in Washington State, so not too far from you.
Dane
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As usual though, you start with an idea, build it, see what worked and what failed, then decide whether you can improve it, or start over. Improvements are made until you have a big pile of crap hiding out back, and a success story in your hands to show everyone. Then people call you a genius!
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Jude, theoreticaly with bows each time you double the size you 8 times the payload and 8 times the stored energy and double the dstance, don't quote me on that but i think I saw that when researching somewhere. I plan to start with a 12 ft bow then a 24 ft bow and these should tell me a lot about how it will scale up. Going to use a simple pyramid design to avoid tillering, will also allow some slack in the design instead of trying to peak it out right away. More intertested in the scaling process than peak performance at this point
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I am only going to leave that pic up a couple of days then remove it, i don't think I am supposed to post it LOL. Steve
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Jude, regarding size of artillery, I think that was not the same issue for a Roman army as it is for us. Some of the machines were absolutely enormous monsters, based on the sizes of stones found at various archeological sites. They were far too complex to have been built on site, as some would suggest, but were probably transported from centralized shops, or borrowed from allied city states and forces at times, too. Transportation and logistics are a big factor in who wins and who looses a battle or a war, then and now. I’ve designed my little 2” (spring diameter) arrow shooter so it fits into the hatchback of my Saab 9-3. Easy to move, easy to play with, and it does reflect the small size of the arrow shooters that would have accompanied a late Republic / Early Empire legion.
One guy in our legio built a very small stone throwing ballista. Small is relative in artillery. It weighed over 3,000 pounds and took a huge trailer to transport, was dangerous to set up and break down (each of the two spring assemblies weighed close to 300 lbs and took 2 guys to manhandle), and had teething problems never resolved because it was impractical to transport and use. We only fielded it 2 or 3 times over a 2 year period. It is sadly now the property of a Hollywood prop house.
Steve, that machine looks familiar :) I recall telling my wife while watching the episode “Oh, that’s Steven Gardner.” Then I had to explain who you are. I think she thinks all of us have too much time on our hands, and are prone to violence, but as I point out, it’s better than my hanging out in bars all day and tipping strippers. What is debatable is which activity is more fun.
Dane
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Dane, I actually had built several versions of that same machine in smaller scales trying to fine tune it. The best results I had were converting it to a trebuchet. So much of the energy went into rotating the drum and lifting the throwing arm that the efficiency was horrible. As a trebuchet I was able to tune in a stall speed allowing the payload to stop the arm sapping all the energy back out of it. More than doubled the distance I was getting. Steve
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Steve, sounds a lot like the same challenges facing an onagar builder. Those too use a sling to hurdle the stone. Most people who build follow Payne Galloway or Marsden, or some of the other earlier builders like Schramm. In the smaller machines, stopping the forward momentum of the arm is one of the big challenges, and where failure most often occurs. I have a friend really into these machines, if you want me to put him in touch him.
So you had build that same Da Vinci design before? Do you have any photos of your work? It is a striking looking machine, no pun intended.
Dane
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Dane, I hadn't really looked at the catapults too much until the show came along. I folled around with the prototypes durring and after the show was completed. I doubt if I will do much more with seige engines besides this last project I have set for myself. If I don't get the results I am hoping for with a 20 footer i will likley just abondon the project. I belong to a sight called catapult message board. These guys are brilliant some of the stuff they are comming up with. I iamgine your friend proably frequents this sight as well. Steve
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Badger...now that is quite the Contraption there...I would really like to see that work.....in Person!!
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Dane, I hadn't really looked at the catapults too much until the show came along. I folled around with the prototypes durring and after the show was completed. I doubt if I will do much more with seige engines besides this last project I have set for myself. If I don't get the results I am hoping for with a 20 footer i will likley just abondon the project. I belong to a sight called catapult message board. These guys are brilliant some of the stuff they are comming up with. I iamgine your friend proably frequents this sight as well. Steve
Steve, could you send me the url for that message board. I may already know it, though not sure.
As for me, the catapults are more facinating than bows, so much is unknown about them, and a great deal of work is to be done in the field. My plans down the road are to build a gastrophetes (belly bow), probably the first catapult, a little hand held machine featuring a composiite bow. The closest that has been attempted was one by Schramm in the early part of the last century, but he used a metal bow. The arcuballita is interesting, as is one scholar's theories about tiny hand held dart shooters. The Hatra machine is something no one has tried to recreate, an inswinger with an all wooden spring frame.
Ultimately, I want to build a machine using only the tools and methodologies available to the Greeks and Romans. That means to me all hand built using forged metal tools, ancient metal working, alloys, and casting methods, and even the raw materials gathered and processed as we think they would have been 2000 years ago. I've been compiling the tools (chisels, draw knives, etc. Not cheap, but the work of one smith I buy from is exceptional), and am starting to use them in regular projects. This machine will have sinew ropes, etc.
Dane
Dane
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Jude, theoreticaly with bows each time you double the size you 8 times the payload and 8 times the stored energy and double the dstance, don't quote me on that but i think I saw that when researching somewhere. I plan to start with a 12 ft bow then a 24 ft bow and these should tell me a lot about how it will scale up. Going to use a simple pyramid design to avoid tillering, will also allow some slack in the design instead of trying to peak it out right away. More intertested in the scaling process than peak performance at this point
Steve, well, it looks like I wasn't too far off with my 6' 50# bow becoming a 12' 400# bow. Good to see I'm not losing my mind just yet. The point I was getting at in my long-winded, meandering sort of way, was that the wood itself would be under twice the strain in tension and compression in the 12' bow. I think the bow would have to become progressively more of a flatbow as it grows, increasing more in width than in thickness, for a big bow to work. However it turns out, it's likely to be a fun project. I just wouldn't want to be in the way if it blows. I don't think artillery failures are a pleasant thing, regardless of the propellant used. Good luck.
Dane, I was just going off on a tangent there, sorry. It just occured to me that since the propelling force of modern artillery is based on volume, not on surface area and distance between working surfaces, we can scale up artillery as much as we want. As for portability, the biggest thing we use in the Army today, is essentially a 6" gun. The 8" to 16" guns of ww2 are gone. The German railcar guns required an entire battalion, of around 800 men to service one piece. They only had 2, because they weren't practical, and used them as an intimidation tool, rather than a tactical tool.
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Jude, the older artillary pieces are interesting. I was never a redleg, I was an 11Bravo. When I was in Germany, I was with a Pershing warhead detachment, another form of artillary which would have made a very large boom had we used them. None of us would be here on this board though if they had ordered a fire mission. One writer called the Cold War era infantry the doomsday grunts, which I think is appropriate, and wish I had coined the term.
Dane