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Garrett Hazen
Location: California Joined: 30 Aug 2006
Posts: 57
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 Posted: Thu 21 Sep, 2006 3:30 pm Post subject: anyone attempted to build a full-size catapult / trebuchet? |
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i am thinking of different projects to take on, and this one seems to spark my interest? just like those sheilds i am bringing up in the other discussion. anyone ever made a catapult / trebuchet before, or know anything to help get started on one? i am starting to look at books on the subject.
Learn to obey before you command--Solon of Athens
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Joel Chesser
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| Posted: Thu 21 Sep, 2006 4:10 pm Post subject: |
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I think there is a Nova where they did this, its been a few years, but i recall it being a good video. it would be well worth trying to get from a library of even buying.
..." The person who dosen't have a sword should sell his coat and buy one."
- Luke 22:36
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Allan Senefelder
Industry Professional
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| Posted: Thu 21 Sep, 2006 4:20 pm Post subject: |
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It's a series on PBS (or at least thats where I saw it) called "Secrets of Lost Civilizations" and they built two trebuchets, one on a wheeled frame and one on a statick frame to se which was more effective. The got a group of craftsmen together, who specialize working in a variety of fields with period tools, on the shore of a loch in Scotland and built them from scratch. They also built a section of castle wall to use as a target. It was a pretty cool episode. I bought it on tape at the time but I don't know if you can still get it.
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Eric Allen
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| Posted: Thu 21 Sep, 2006 4:44 pm Post subject: |
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Ooooooooh. Trebuchets! Yummy!
I have been seriously tempted to build some model trebs myself. Its one of theso "back-burner" projects, so to speak.
You might check The Hurl and trebuchet.com for tons of catapult information (and even some plans and ready-to-assemble kits!).
That should get you started.
Mechanically and physically a trebuchet is quite simple. A high-school knowledge of physics should be sufficient to grasp the concepts and mathematics. The hard part is the engineering of actually putting one together. Start small then get bigger. A "full-size" medieval-style trebuchet has only ever been attempted in the modern world a handfull of times (some huge trebs out of modern materiel exist, though).
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Mark Mattimore
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| Posted: Thu 21 Sep, 2006 4:56 pm Post subject: |
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| Allan Senefelder wrote: | | It's a series on PBS (or at least thats where I saw it) called "Secrets of Lost Civilizations" and they built two trebuchets, one on a wheeled frame and one on a statick frame to se which was more effective. The got a group of craftsmen together, who specialize working in a variety of fields with period tools, on the shore of a loch in Scotland and built them from scratch. They also built a section of castle wall to use as a target. It was a pretty cool episode. I bought it on tape at the time but I don't know if you can still get it. |
I loved that show.  Here's the website.
http://www.pbs.org/wgbh/nova/lostempires/trebuchet/
Not a lot of DIY information but still fun.
In omnibus requiem quaesivi, et nusquam inveni nisi in angulo cum libro.
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Bob Burns
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| Posted: Thu 21 Sep, 2006 5:02 pm Post subject: |
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Ah yes, I've got that DVD from Nova on the two Trebuchets, I've been collecting documentary DVDs and movie DVDs like wildfire, this is a really good video and well worth owning. I got a kick out of it when they launched a piano and it busted apart into smithereens when it hit.
It was quite interesting watching them gauge the distance and make the adjustments, even with a large crew of highly skilled tradesmen it was quite a challenge for both teams. Even to build a 1/10th scale would be fun, I believe they sell plans for this at www.trebuchet.com
Bob
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Allan Senefelder
Industry Professional
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| Posted: Thu 21 Sep, 2006 6:21 pm Post subject: |
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Bob, the piano immediately got me thinking of odd things to throw, that bit was great.
A guy I used to know who worked as an engineer for GM got together with his buddies an built a smaller one (25-30 feet high) and used 4 plastic 55 gallon drums as the counter weight. This way with a little trial and error they were able to mathematically figure out based on how heavy what was being throw was, how much water at ? lbs per gallon was needed in each drum to throw the object X distance. In the video he showed me of it working they used a VW Rabbit as the target and were throwing the disc break from a truck. The had to use a tractor to pull the disc break drum out of the car, one shot entering midlength on the hood and lodging in the back seat. They threw a push mower for fun as well which looked rather silly while going through the air but did lodge intself pretty well into the ground,and of course come apart.
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Eric Allen
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| Posted: Thu 21 Sep, 2006 8:32 pm Post subject: |
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My cousin's neighbor built a trebuchet for a physics project. He set it up in his driveway and has it calibrated to shoot basketballs at the hoop.
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William C Champlin
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| Posted: Thu 21 Sep, 2006 9:16 pm Post subject: |
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Hey. The summer between jr. and highschool a friend and I built a small one that, as I recall, would toss a brick for two or more blocks. It's been thirty plus years but I'll look around and see if I can find our source. W.
tweetchris
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Colin F.
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| Posted: Fri 22 Sep, 2006 12:36 am Post subject: |
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I visited Caerlaverock Castle a few weeks ago and they have a full size trebuchet and a full size mangonel. When I get to uni (and on a fast internet connection) I'll post the pics I have, but please accept my apologies for the lack of quality before hand, as they were taken on my phone.
Melchett - "In short, a German spy is giving away every one of our battle plans."
Cpt. Darling - "You look surprised, Blackadder."
Edmund - "I cerainly am, sir. I didn't realise we had any battle plans."
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David Ruff
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| Posted: Sun 24 Sep, 2006 4:57 pm Post subject: |
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I have a 1200lb roman scorpion sitting here. It pulls 1200lbs and is a two man ballista (not a treb or cat, but still fun) It fires 10lb spears and is fun to hit things with. The wife won't let me attach it to the roof to keep the neighborhood kids, dogs and cats outta the yard however 
David
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Eric Allen
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| Posted: Sun 24 Sep, 2006 9:14 pm Post subject: |
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| David Ruff wrote: | I have a 1200lb roman scorpion sitting here. It pulls 1200lbs and is a two man ballista (not a treb or cat, but still fun) It fires 10lb spears and is fun to hit things with. The wife won't let me attach it to the roof to keep the neighborhood kids, dogs and cats outta the yard however
David |
 Dude! Pictures! Please!
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Garrett Hazen
Location: California Joined: 30 Aug 2006
Posts: 57
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| Posted: Sun 01 Oct, 2006 7:14 pm Post subject: |
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where do people find the plans to make those machines anymore? i cant seem to find any like that. the biggest ive seen posted on the internet are those 1/10 scales of a warwolf trebuchet. i cant find any BIG ones that David Ruff seems to have made. hopefully sooner or later youll put pictures up right David?
Learn to obey before you command--Solon of Athens
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David Ruff
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| Posted: Tue 03 Oct, 2006 8:26 pm Post subject: |
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| Garrett Hazen wrote: | | where do people find the plans to make those machines anymore? i cant seem to find any like that. the biggest ive seen posted on the internet are those 1/10 scales of a warwolf trebuchet. i cant find any BIG ones that David Ruff seems to have made. hopefully sooner or later youll put pictures up right David? |
There was a question as to this machine he built. David is out of town currently working on a set. He will be back in a week. They pull that monster out every year to shoot it and i know he was talking about taking pictures and measurments for a private message he got about it some time back.
The plans and build was done via a friend of a friend that had plans to it. Everything on it had to be hand made and the metal work for the top section was bought from his friend with the plans. It is quite impressive to see fired and i will be sure to have him get video of it firing when they pull it back out for the yearly show.
Kay (answering emails and such for david)
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Jean Thibodeau
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| Posted: Tue 03 Oct, 2006 8:56 pm Post subject: |
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| David Ruff wrote: | | Garrett Hazen wrote: | | where do people find the plans to make those machines anymore? i cant seem to find any like that. the biggest ive seen posted on the internet are those 1/10 scales of a warwolf trebuchet. i cant find any BIG ones that David Ruff seems to have made. hopefully sooner or later youll put pictures up right David? |
There was a question as to this machine he built. David is out of town currently working on a set. He will be back in a week. They pull that monster out every year to shoot it and i know he was talking about taking pictures and measurments for a private message he got about it some time back.
The plans and build was done via a friend of a friend that had plans to it. Everything on it had to be hand made and the metal work for the top section was bought from his friend with the plans. It is quite impressive to see fired and i will be sure to have him get video of it firing when they pull it back out for the yearly show.
Kay (answering emails and such for david) |
Kay, just thanks for answering David's e-mail and giving us some useful information at the same time.  
A question he can answer later is that I find it puzzling that a large siege machine that at 1200 pounds can throw a 10 pound spear but that a heavy but much smaller crossbow of equal draw weight seems to use much lighter missiles closer to 1/4 pounds or maybe 1/2 pounds ? There seems to be something not obvious about this ?
A few possible explanations would be that the 10 pound spear has a much lower velocity or that the draw length on the siege machine is much longer and thus more efficient than with the siege crossbow.
One pet theory of mine is that crossbow bolts should be much heavier than usually assumed to get good efficiency from very heavy prod The maximum effective weight being the weight giving the most momentum to the bolt and not the maximum velocity.
Another theory would be that this siege engine at 1200 pounds is at the lower end of how strong a similar sized one could be ? maybe 5 to 10 times more power giving crossbow like velocities to a 10 pound missile ?
You can easily give up your freedom. You have to fight hard to get it back!
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Joel Whitmore
Location: Simmesport, LA Joined: 25 Aug 2003
Posts: 342
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| Posted: Wed 04 Oct, 2006 8:43 am Post subject: Small ones |
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I built 5 small ones fro my math class (12") high. The buckets held marbles and we shot jellybeans. Students collected data on distance as a function of the number of marbles in the bucket. I then divided them up into teams and they each had 5 shots to hit the other at a random distance. Those who were careful in their data collection got a better equation and tended to be more accurate. It was fun and the trebuchets looked cool. I'll try to find a pic.
Joel
 Attachment: 46.63 KB
Here's a pic with one of my students about to collect seige engine data!
Last edited by Joel Whitmore on Wed 04 Oct, 2006 6:36 pm; edited 1 time in total
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Addison C. de Lisle
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David Ruff
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| Posted: Wed 04 Oct, 2006 3:39 pm Post subject: |
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| Jean Thibodeau wrote: | | David Ruff wrote: | | Garrett Hazen wrote: | | where do people find the plans to make those machines anymore? i cant seem to find any like that. the biggest ive seen posted on the internet are those 1/10 scales of a warwolf trebuchet. i cant find any BIG ones that David Ruff seems to have made. hopefully sooner or later youll put pictures up right David? |
There was a question as to this machine he built. David is out of town currently working on a set. He will be back in a week. They pull that monster out every year to shoot it and i know he was talking about taking pictures and measurments for a private message he got about it some time back.
The plans and build was done via a friend of a friend that had plans to it. Everything on it had to be hand made and the metal work for the top section was bought from his friend with the plans. It is quite impressive to see fired and i will be sure to have him get video of it firing when they pull it back out for the yearly show.
Kay (answering emails and such for david) |
Kay, just thanks for answering David's e-mail and giving us some useful information at the same time.
A question he can answer later is that I find it puzzling that a large siege machine that at 1200 pounds can throw a 10 pound spear but that a heavy but much smaller crossbow of equal draw weight seems to use much lighter missiles closer to 1/4 pounds or maybe 1/2 pounds ? There seems to be something not obvious about this ?
A few possible explanations would be that the 10 pound spear has a much lower velocity or that the draw length on the siege machine is much longer and thus more efficient than with the siege crossbow.
One pet theory of mine is that crossbow bolts should be much heavier than usually assumed to get good efficiency from very heavy prod The maximum effective weight being the weight giving the most momentum to the bolt and not the maximum velocity.
Another theory would be that this siege engine at 1200 pounds is at the lower end of how strong a similar sized one could be ? maybe 5 to 10 times more power giving crossbow like velocities to a 10 pound missile ? |
I think i understand what your saying. I know this just by comparing the heavy crossbows and the ballista. The ballista tip to tip is about 6 feet. The spear it throws is about 5 feet long, the tip on the spear is sticking out the front of the ballista about six inches. So if i am reading your thought correctly, yes the ballista has a huge span and long time to push the spear then a crossbow does.
I do not know the speed of the ballista spear, the last time i saw it fired it was fired along side longbows. the spear was traveling faster then the arrows were as the spear hit a target before the arrows did. The spear also did a lot more damage then the arrows did.
David can answer all that when he comes back.
The best
Kay
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