1. Range needs to be 300?X the arm length deep. More, if the projectile can bounce and keeps going.
2. How wide?
3. Will people wander through the range?
4. How much room behind? Do projectiles or trebuchet parts ever get thrown that way? How far?
5. Block spectators out of the area the sling will whip through (traffic cones? Posts and cords? A moat?)
6. When trebuchets, er, rapidly disassemble themselves, how far and in what directions do bits generally go?
7. Any need for PPE (Personal Protective Equipment)?

Thanks in advance!

Thanks

Streetta

search this string in youtube, please.

the link above is a series of fires with a treb the Cal Lab built in our off-time built for a Subbase New London Morale boosting event.

We had a ton of fun doing it. Especially since we all work in the electronics field and got to wrap our heads around a mechanical, physical problem.

Throwing arm is 8 ft. 105" weight drop of 195 lbs (I think underpowered but out bar was 1/2" blackiron pipe, maxed out). axle is 2.75 feet from weighted end. After tuning (you can see a couple shots go not so well in the first part of vid) sling length was 6 ft., release pin at about a 50 degree angle. Max distance was 67 yards by laser rangefinder and spotter.

So it was the first time we did something like this, and we got outshot by only one of the other trebuchets, who had the full 15 ft throwing arm and 750 lbs of counterweight allowed in the rules, not too bad.

Wanted to share this beast and look for some constructive criticism. enjoy, and fire away.

Thanks for your help!

Thanks for the help,

BeardedOne

I am designing a tiny FAKA trebuchet out of popsicle sticks and other assorted scraps of wood.
How do you calculate the proper track length?

My planned projectile is a 4.77 gram marble.
My planned counterweight is 16.8 ounces (about 470 grams).
The planned height of the frame is 4.5".
The height of the arm (hanger and upper arm) is 9".
The wheel carriages are 1" in length.

How should I calculate the track length?

I have built and tuned a FAT trebuchet on the same scale.

Thanks!

Anyway, here's the plan so far. We are using pre-treated 4x4s for the frame, the base is 5' by 10', 12' high at the axle with a 16' sling arm. We found a good piece of 1 1/2 inch steel pipe that's 6', so we have enough to either cut down or keep some extra, depending, that we will be using for the axle. We will be using a 55 gallon drum filled with water for the counterweight.

What we are trying to figure out is the idea of using bearings for the axle to reduce the friction. Either by fitting a pipe around the axle at the sling arm and putting bearings in it, or fitting pipe around the ends of the axle and having the bearings there.

Our biggest question is, if we use bearings on the ends of the axle will the weight make it malfunction? Or if we put the bearings at the sling arm?

This is our first shot at making one of this size, we have made a small tabletop trebuchet but it doesn't compare to what this thing will be!

If anyone reads this, I really appreciate it.

Dominick

I am hoping that this forum can best answer a question from a newbie. It's a bit unusual. I am designing professional pitching horseshoes and want to create a piece of equipment that will test launch each design as if it were pitched by an individual between 27 and 30 feet. I have been experimenting a bit with moving around the center of gravity of the designed horseshoes by adding and subtracting weight from various locations around the perimeter of the horseshoe. I want to be able to create a device that would simulate a person pitching the horseshoe underhanded. It seems that my simplest solution would involve a spring of strength necessary to pitch the shoe with a trigger release at the appropriate location.

I need to buy the necessary spring, but, don't know how to calculate the strength necessary and convey the request to a spring company. I would assume a launch angle between 30 and 45 degrees. Weight: 2-1/2 pounds. Release point: About 3 feet above the ground. Any help appreciated.

Thanks!

My name is Jasper and I'm a role-playing game designer. I've been working on a project involving a fictional war machine of absurd proportions and I wanted some help with the hows and the whys of the concept.

Within the setting of the game i'm working on the Bad Guys have a giant trebuchet that is only briefly described in the existing text. My job is to flesh out how it works, what it's made of and what it is capable of.

Here is what I know-

The main throwing arm is an entire tree. A fictional, super strong and flexible wood called Icewood. Icewood trees grow to impossible proportions (300-500 feet). The tree that makes the main arm of the weapon is 400 feet long. Icewood is described as being lightweight, flexible and remarkably resilient.

The empire that has built the weapon has an effectively unlimited amount of manpower and resources to use in it's construction, but relatively crude technology. Roughly that of 14th century craftsmen. In my mind, this weapon is on the same scale of engineering that built the Pyramids and the Great Wall of China.

So, the question is, if you had effectively unlimited manpower and resources, 14th century crafting technology and a nearly perfect 400 foot main arm, how would you build this weapon and what could it do?

What would it's dimensions be?

What materials would you use to construct it?

How heavy should/would the counterweight be?

How heavy/large could the payload be?

How far could it hurl?

How long would it take to reset and reload?

I'd like to use a Floating Arm Treb for the design, even though it isn't historically accurate (it's fantasy after all), but I don't know if the sheer scale of it would make that design tear itself apart when it fires. (the track-and-wheel system seems vulnerable to scale issues, but I'm by no means an expert.) If the FAT wouldn't work, that's fine. The above questions still stand.

Thanks for the help!

- Jasper

image

http://forum.istorija.net/forums/thread-view.asp?tid=3931&mid=61246#M61246

Just some quick specs…

The competition requires throwing a gallon milk jug full of water (8.35lbs) 45-60 yards. Trebuchets only, no catapults. Scores are based off of how close we are to hitting a "castle wall". Our actual competition is this weekend.
We built a HCW trebuchet out of 2x4's and 2x6's and are using 300-400lbs of counterweight.

Thank you for your time and resources….
~Levi

If you wish to compete in the event email moc.rr.wen|sinedtapts#moc.rr.wen|sinedtapts

Conor

I have also been trying to make popular pages more user friendly for people new to hurling. Generally this means linking simpler content, having some background text, and providing videos.

I also intend to expand to cover more topics. Things like kits, materials, more basic simplified tuning information, longer machine type descriptions. I might even make a section for sling shots, spoonapults, and other odd designs.

Basically, I built a copy (sorry, its too cool!) of your Golf Ball Beast over the past three weeks. I have the frame done, but one major setback I am having is the throwing end. I have an arm, the counterweight arm, primary and secondary triggers, but i can never get the arm to stop its forward motion after it has flung. I'm hoping it will be as simple as adding a projectile, but I don't know. I guess I am just horrible at tuning.

My tuning method thus far has been to rotate between the holes I have drilled in the arm and the counterweight arm, trying to get that perfect combination, but to no avail. Any tips and or pointers?

Thanks!

http://www.youtube.com/watch?v=7UNmxO_l2ig

http://www.youtube.com/watch?v=9jyINsWxvqk

I have some ideas to help; I'm pretty sure I can get at least half of the energy by modifying some parts, though I will likely have to remake the complex trigger mechanism.

For now, I'm going to fix the few issues (slipping knots and such) then go throw some stuff. In the bright side, this machine could dry fire safely loaded with 50 pounds. A miss fire where the sling actually deploys could be an issue though.

As I have progressed with this implementation of the design, I have realized several flaws in my machine that should be changed for future ones. Changes can be made to tolerate elastic parts better at the cost of arm drag for example that would be good for a flimsy machine like mine, and least until I get some less stretchy string. Also, before the CW detaches, the transfer of energy may not be as complete as I want because of the same stretchy string and some minor building errors/choices. Again, the next one will be better in this respect.

I'm quite worried about the sling. With the axle around 3.5 feet off the ground, and a 4 foot sling, things could get ugly. 7 feet of string slapping the ground/treb! Also, the tuning literally chooses the release angle, though the first throw will basically be at a random angle, and the next one should fix it, but a random angle on such a machine is bad as it might just slam the sling and projectile into the ground!

The CW came out more compact than I thought, so it should hole a few extra 5 pound disks if desired, but I will have to modify it to work with my planned initial test weight (5 or less pounds) because the CW arm would not properly clear the arm assembly if I simply make it skinner when I remove weights as planned. Also, the primary trigger needs to be designed, but it should be trivial.

I also gathered the remaining parts of the frame, though I still need to locate some hardware and such. I'm really looking forward to getting this thing tested, though I will have to start with just a few pounds of CW so wont out throw my local park. Looks like the treb might actually work!

Now, I think it will work. I always can confidence in the concept, but my implementation of it has left me wondering it it would actually work. Maybe as soon as next week I will be able to get some real throws off.

We are also looking at other suggestions at trebuchets. (F2K Series disqualified)

Thanks!

My brother made 2 trebuchets but they both broke. They could fire a half-pound brick about 50 feet. We used lead plates as weight.

They were fun while they lasted.

• LA: 2 feet
• CW drop: 6 feet
• CW: 15 pounds
• Projectile: Golf ball
• Sling: 4 feet
• Maximum possible design efficiency: 100%
• Axle height: 3 feet
• Total frame height: 3 feet

I'm quite happy to finally have a design where the efficiency is only limited by how well it is built (friction etc). That 100% requires no friction and perfect tuning, but not a massless arm, or anything like that. It also looks like the 100% efficiency should be possible with much higher mass ratios, and even more drop (CW drop is easy to add). I would also like to say that the only long beams in the whole design contribute to the CW, have no bending load (possibly a slight bending load during cocking depending on how it is cocked), and only a mild compression load. The whole machine should fold up very well (could be made to fold up just like merlin, but easier) and could be easily scaled up to trailer size. It has no rolling or sliding parts, and no moving parts that can hit each other excluding the sling and projectile. This means no arm vs. hanger whipper death, no FAKA end of track slamming, and no rolling axles, CW guides or anything like that at all. Because of this, and some other reasons, it should be relatively easy to build. There are some small complex parts, but nothing too bad really.

Also, it should be the easiest treb design to tune that I have ever seen. It should be able to be fully tuned by adjusting two things (one is the firing pin) which do not effect each other. You can literally adjust the release angle forwards of backwards any number of degrees (no guess and check ether!) with out messing up the other tuning (consisting only of the firing pin angle).

The one main issue that I see is that the sling can potentially hit the ground before and/or after the release. It is similar to a whipper in this respect.

September

September 29, 2007: Burlington!

Burlington was great! I will get some videos up eventually, but I don't have room to edit them now. A ton of great pictures were uploaded. See them on the main page for now.

September 22, 2007: Pumpkin On A Stick testing!

Also, the arm got a bit screwed up when the pulley broke because the load became unbalanced because it rubbed on the screws.

The disadvantage of the double redirect system is that it triples the load on the frame which seemed to be too much with 3 people.

On the bright side, it actually worked and threw around 20 yards with a completely horizontal release. We might get 100 feet with just 2 people which would be cool.

August

August 28, 2007: Traction!

No traction treb yet, but the frame is nearly done (it needs 4 safety pegs installed). Plans for the arm are developing. I have some great plans, but nothing is sure yet. It will be cool; I can say that.

August 21, 2007: Onagenator 2 broken

Today Matt and I set out to test the minor changes to Onagenator 2 including a reinforced draw down loop on the arm, pins to prevent the bundle from unwinding and a longer sling. Because of space limits we used a heavier 5 ounce lacrosse ball rather than a golf ball as a projectile. The sling was too long for the heavier projectile, but the the changes worked well, too well. We increased the bundle twists in large increments to quickly get up to last times failure point where the modulus slipped. Our new pins worked (but bent) however with our greatly increased torque there were problems. First our spanner has some minor problems, but that would be easy to fix. More importantly one of the pegs in the modulus that the spanner hooks up to got pulled out of alignment as the oak deformed. This did not stop us, and nether did the breaking off of one of the onager's feet which don't do much now. What did stop us was much more impressive, the sliding release trigger rated at 150 pounds failed. I don't know how, but the trigger clearly released while we were cocking the onager. As always during the cocking and loading process all people were clear of the plane of rotation and no one was hurt, but the most amazing thing happened: we broke the arm into three pieces! The bottom break was just past the end of the bundle in the steel reinforced section. The steel clearly need more wrapping to add sheer strength as it was intended to resist compression which it did. Video will be added soon! (Sorry, no video of the break) See onagenator2 page for pictures

August 17, 2007: Burlington Info Received

Today I finally got the information I needed about the Burlington Pumpkin Pitch. If all goes well there will be a youth division 11-17 throwing 4 pound pumpkins which I will compete in. Should there be less than three entrants in the division it will not exist and I will be throwing 8 pound pumpkins in the adult division. I may take action to make the youth division exist by finding some other people to enter it and/or entering more than one device. Should this status change it will be updated here.

August 2, 2007: Mini KA day Two

July

July 31, 2007: Blog Creation and Mini KA

Today I created this blog about my hurling. For earlier information see my blog on the hurl.

My Mini KA:

The day before yesterday I started making a small King Arthur inspired by the great CW I had laying around: A 3 1/4" long 2" diameter can filled with 3 1/2 pounds of solder. I grabbed a few pieces of 1/4" by 3/4" wood and started cutting with no real plan. A bit different from my normal computer modeling then building process. I finished the trebuchet yesterday and tested it today.

Stats

CW: 3 1/2 pounds
Projectile: 1 1/4 ounces (roughly)
Axle Height: 13 1/2"
Long Arm: 12 3/4"
Short Arm: Adjustable (4 1/4")
Sling: Adjustable (13 3/4")
Wheels: Yes!
Frame: 1 1/4 pounds (roughly)

Results

Test went well. Tuning was very good, but room was lacking. My joke desktop trebuchet with almost an equal sized counterweight and projectile, but 45:1 mass ratio, threw through part of a tree and uphill for a range of roughly 50 feet. I hope to do some testing with more room soon.
Frame seems quite strong (Took a few misfires and getting flipped) but the original axle bent, probably when the frame bounced; it gets about an 1 1/2" of air under the back wheels on a regular throw. New skinnier and stiffer axle works great.

Short Video

Long Video

Basically the plan is to understand the CW to Arm energy transfer enough to manipulate it to get what we want, then understand the arm to sling transfer figure out what we want from the CW to arm transfer timing.

The blogs are being moved to forum topics where posts can be commented on and feeds can be generated.

Competitions

There is now a Competitions section of this site which will have information about the different competitions. The competitions have topics which generate feeds just like the blogs.

Machines

The machines pages have been moved from the machines section of the site to the device types, but a list of the machines is still available on the machines page.

2007

August

August 20, 2007: Machines and Pictures

Yesterday I added the machines section of this site. I think it will work really well. I added one machine and will continue to add more. I also made a flickr group for hosting images for us. It is great because with one line of text we can generate an image gallery with all the images with a certain tag. For examples see the Mini KA or the King Arthur page. I will do this for all the other types as pictures get uploaded into the flickr group.

August 19, 2007: New Organization and Improved Navigation

The entire site here has been completely reorganized. The structure is nor hierarchal through parent pages which automatically generate page lists and the site map in the navigation bar on the left and on the main page. Also check out the new glossary. It needs much more content, but should be really easy to extend.

August 18, 2007: Reorganization

Yesterday and today I reorganized all of the device type content. Here is a quote from message on the front page about it.

This site is undergoing a reorganization of information and pages. A good organizational method has been found; to see an unfinished example view the trebuchets page. Eventually all the device types will be organized that way. A page like that will also be added for general multi device things like tuning or arms. Device specific information on these subjects will be on the device's page which will link to the general page. The general page will also have a link to a list of devices with specific additional information for them by linking to the tag page for that topic or using back links. This system should allow for vast amounts of specific and general information to be available while keeping it simple to find what you need.

August 14, 2007: New Theme

I just finished getting a functional new theme done; it is light on dark which I prefer. Because it has some issues, I only applied it to personal pages. If all goes well it will likely be applied to the whole site.

August 13, 2007: More Content and Site Plans

I wrote the tuning information for King Arthurs on the tuning page and wrote and added the slings page. We seem to have quite a bit of content here. We might even develop some plans or construction tips for the different aspects of designs such as the slings page. Things like how to build torsion bundles and such. I also am planning on adding some information on KA triggers to the triggers page soon to stick to my goal of having answers to all people's general question on The hurl here; I might start adding information to this site and posting links to The Hurl rather than answering posts there in some cases. Still no new edits from anyone else. To cut down on the test I have to write I'm starting to refer readers to other sites whenever possible. When I have more time, or other people add some content these referrals will be changed to references and alternate sources; I would like to have this site be complete and not rely on other sites to fill gaps in its content partly because these other sites can not be updated by us like this wiki, and partly because it is easier on the readers, and multiple sources of information is always a good thing. Nothing major happening traffic wise on the site lately, just less page views per visit, but longer visits. It is probably because the pages actually have content that takes time to read now.

August 11, 2007: More Content

I think all of the pages have some content now, but there are still several empty sections. I just finished writing up most of the Arm Designs page which is looking quite good I think. Traffic has been growing consistently too. Lots of hits from Google searches (about 12 percent of total hits) which surprised me. Only 45% of visits have come directly from The Hurl, so I'm not just leaching off of it. Good to know, however one of my main motivations for creating this site was to have a location to direct people's questions too, and add answers to general case questions. 204 visits from 154 visitors so far. I hope this site has been useful for at least some of those people. As always more content would be better, and I will continue working on it. I'm still surprised and a bit disappointed that I'm the only one one working on the site, but that may change with time.

August 6, 2007: Content

I have been adding content frequently, and we now have quite a bit. I seem to be the only one working of this site, which is ok, but it will grow much faster with some help. The site has been getting decent traffic: 181 visits from 81 visitors. Not bad!
Probably the most complete and useful pages are:
Links
Tuning
Abbreviations
Site-Faq
Useful but quite incomplete:
bundles
Hurling-Devices

To get a list of pages that need content click the "under-construction" tag in the side nav bar.

There are also the personal pages, currently just this one, and my other blog about hurling rather than this site.

July

July 26, 2007: Activity

We have been getting some traffic on the site (quite a bit actually) but very few contributions. In face I have done well over 100 edits and updates (Well, half of those were just me figuring out what I was doing or fixing stupid typos), and other than mine there have been two, one fixing a typo and one improving the formatting on a page. I'm guessing the main reason for the lack of edits and such is because no one really wants to add content, or more likely editing the pages does not look easy. Editing and creating pages is really quite simple, but there are a few things to get used to, so feel free to play in the sandbox where you can freely mess with content to get used to it. Just press the little edit button in the bottom right. Also, all pages have every version changed so if something gets screwed up it is easy to fix so don't worry, just revert to previous version. If you can't get the formatting right it's fine. I will get it formatted all nice in a day or so.
Some activity stats: 35 visits from 18 people not counting me. Not bad, but we need more content. I'm not an expert on everything so I'm starting to run out of stuff to write.
I made several pages with an outline that just need the all or some of the content filled in. Just flip through the top part of the left hand site nav bar.
If you have any questions you can ask them on the forms.

Results

The official results for the Burlington Pumpkin Pitch

Team Awards

• Machine Engineering Award-
  • J-Buchet (Janicki), Sedro Woolley, WA
• Team Sportsmanship Award- (tie)
  • TreBarbaric, Sedro Woolley, WA
  • J-Buchet, Sedro Woolley, WA
• Captain's Award- (tie)
  • TreBarbaric, Sedro Woolley, WA
  • Pumpkin on a Stick, Seattle, WA
• People's Choice Award-
  • TreBarbaric, Sedro Woolley, WA
• Rookie of the Year-
  • Pumpkin on a Stick, Seattle, WA

Competitive Division

• 1st Place
  • TreBarbaric, Sedro Woolley- 1866.8ft "New World Record"
• 2nd Place
  • J-Buchet, Sedro Woolley-1083.9ft
• 3rd Place
  • Siege Perilous, Kingston, WA-999.6ft

Recreational Division

• 1st Place
  • Gourdinator, Sedro Woolley-992.3ft
• 2nd Place
  • MiXeD NuTS, Everett, WA-471.9ft
• 3rd Place
  • U.F.O., Burlington-432.2ft
• 4th Place
  • Ally-Oop, Surrey, B.C.-395.2ft
• 5th Place
  • Trebasaurus, Mount Vernon-375ft
• 6th Place
  • Pumpkin on a Stick, Seattle, WA 84.4ft

Pictures

See the Burlington Pumpkin Pitch Page.
The picture gallery can not be posted here for some reason.

I guess if groups or teams wanted to be able to share editing a page or set of pages I could set that up too upon request.

Any thoughts about this? Sound like a good idea?

I think as much as is reasonable be on TheHurl.Org because it is not some random third party host like this is (However nice) and Ron nicely gives us unlimited file space. Here we only get 100 mb so file sharing and personal image galleries need to stay on the hurl along with personal/device related threads which may have temporary images and such because those images pile up fast. Basically these forums will only be for stuff about this wiki site.

So what does go here? Lots of information, just no questions about hurling. (Questions about the site are fine on the forums, hurling questions should be on TheHurl.Org) Information that will continue to be useful should be here. Information about designs, definitions of Abbreviations and Types of Hurling Devices should be here along with some Links, but what else? Maybe a FAQ, Plans, Construction and design tips, statistics, contest information and may other things could be here. What do you think?

That is my idea anyway. Let me know what you think.