The classic beam ratio for a FAT is 2:1. The two previous segments are diagonal supports. 15. (0.635 cm) bolts, matching thread Here, we followed the dimensions on the drawing and cut very precisely. Arm-sling constraint, arm roller on fixed track, projectile on ramp. So, use the turnbuckle system I mentioned in the introduction. In this high-efficiency design, the counterweight is constrained by a track to fall straight down. A traditional trebuchet, which is simple to engineer, consists of an arm resting off-centre on an axle with a hinged counterweight at the short end of the arm. Really hope we get the hooks and sling parts to make trebuchets wor Drill the holes for the eye bolts. circular saw (The one I used here) OR miter saw AND table saw drip some wood glue into the holes, and put glue all over the dowels. If you make the channel a lot wider, I would suggest using a wider piece of wood or strength. The trigger pins keep the weight from falling. drill (The one I used here came in a kit here) with a varied drill bit set, for pilot holes, etc. your best bet is to experiment with different sling lengths and pin angles. thick plywood, 2 ft., 5 in. anyways First, I'm going to talk about some other improvements that are more important than the arm. You need: Could be built in probably a few weekends. You can cut the gap wider up to a certain pint, but the trigger design might limit the amount you can cut it wider. Keep the top part aligned, and carefully trace a line on the diagonal along the edge of the base. I would greatly appreciate it if i can take a look at it. The person holding the arm up can relax. Then just screw the bolt through when you need to. 4 years ago. 17. but if you didn't (my bad) You need to recut the drop gap to 1/8" wider than the CW bar, cut the gap in the track slightly wider, and spread apart the track supports directly underneath the drop gap. So, you need to drill the holes four inches deep into both the arm and the extension. X 1.5 in. The hardest part, really, is getting the angles correct and then cutting them accurately. A pair of wheels allows the arm to roll along It launches 5 pound pumpkins around 320 feet with 250 pounds of counter weight. The first recorded use of traction trebuchets appeared in ancient China and were probably used by the Mohists ps-mohist are a scientific lead version of the chinese What is the floating arm Trebuchet, and how does it work? Next use a sheet bend (There might be a better knot for this) and tie the 21 foot piece to the middle of the four foot piece. Place the weights in the box and screw on the top. Thats a bit longer than 7 feet because i rounded 7 4.5 up, it was really 1.55555555 i need the axle on the end of the throwing arm to slide up and down within the rectangular slot running up and down the center of the main truss. Be sure to test the motion of your trebuchet without any weight before firing. After the first 25 shots or so with the trebuchet, there were two things apparent: the arm could easily be made longer and could greatly increase the range, and the the CW bolt needed to be made stronger. (0.4318 m) long 2 X 4 8. 0. nuts, coarse thread 6 1/4 in. 15 in. 7 years ago. To dowel the pieces, simply drill two holes into both the arm and the extension. The key ratio of an arm is anywere between 3:1 and 5:1. I will be launching this in a range 200yds and I'm looking to toss under that because I will be demonstrating my trebuchet about 50yds or so from a football field and I will be tossing the weight towards the field and at the other end is a parking lot. For the weight I used ( 36 pounds) a 5/8" HARDENED STEEL rod MIGHT work. Consider cost and use whatever spare or donated materials you can find. I don't know how long to make the rope or how to attach the sling or how it is even supposed to work? I would probably actually be dead. He can back away. You need to lift the counterweight to the height of the supports so your friend can get them just underneath the CW bar. Take a look at our trigger design if you ever want something that works for heavy payloads. Unlike now, the humans pulled ropes instead of having a counter weight. This might change depending on your weights setup. Place the hole for the counterweight bolt about an inch and a half from the end. I keep them in one of the mitered side support screw holes so I can easily reach them once I get the CW to the top. It was determined that the optimal arm length ratio was approximately 1:2, where the short So we built a 10 throwing arm trebuchet. Use the top bolt for screwing in, and the bottom one for unscrewing. This linear drop of the counterweight is more efficient in transferring potential energy to kinetic energy than the pendulum counterweight motion of a traditional trebuchet. This allows us to swap out pins, or adjust forward and backward. (Diagonally). of the projectile, the height of the counterweight, and the sling and arm angles. The arm extension is added onto the rest of the arm with three different methods. fourth through fifth picture will show this. When firing, make sure no-one is down range, near to, or directly behind your trebuchet. These are really simple. In response to urbanmx, this was our very first trebuchet. Approx. Grab your nylon rope and cut 4 feet off the end. Arm-sling constraint, arm roller on fixed track, projectile above ramp. You also will need to push them out slightly, so that the gap is 3/4" at least. This metal loop goes around the pin, and as the centrifugal force increases as the arm swings, the ring slides off the pin to allow the pouch to open. I'd guess that for throwing oranges, you'd want to be around 5-6 ft high and an 8ft arm, and maybe 50-100 lbs of weight? You will need the two 2- foot lengths of 1 X 6 and the two 6- foot lengths of the 1 X 6. [2] The projectile can be launched at a high velocity.[6]. (7.62 X 3.81 cm) diameter wheels, 5/8 id bearing load rating of 200 lbs (90.71 kilos) or more I've definitely seen some trebuchets in that size range throwing tennis balls, 6" steel shot, etc very far. Today we have a look at a modern design for a Trebuchet that still works with Medieval Engineers parts.. WebA floating arm trebuchet's arm is mounted on wheels that roll on a track parallel to the ground, with a counterweight that falls vertically, allowing for greater efficiency by increasing the proportion of energy transferred to the projectile. Does it take a small army to transport it? SolidWorks was used here, although any CAD software or even a hand sketch would be ok. One advantage of 3D CAD was the ability to make an assembly and ensure a good fit for all the components, as well as smooth motion. (0.635 cm) washers, matching carriage bolts wood screws, phillips head drive, #8 I'll write more about this in the improvements step. This would eliminate cracking and make the drop channel much stronger. This is a more efficient way to transfer potential Fun Crafts For Kids Craft Stick Crafts Wood Crafts 6. These should be fairly simple-they're just diagonal pieces. The hardest part, really, is getting the angles correct and then cutting them accura And do lots of testing, with a realllllly long trigger string. 1.6 X 3.5 = 5.6 This means that 3 and 1/2 parts of the short arm plus the short arm itself equal the total length of my entire beam. And send me some pictures :D. I tried to reply but it wouldnt let me so this is my other option. Remember, if you make your drop channel wider for a wider CW bolt, You may need to cut the washers down even more and move the bolts farther to the outside. The person standing on the trebcuhet is no longer in danger unless he drops the bolt on his foot. Ok, now, the base is constructed using half- lap joinery. Then just hammer the dowels all the way into the holes. The thicker the better to prevent it from bending. (remember the CW is supported by the trigger at the beginning, and the the trigger is screwed directly into the drop channels. ) I really want to build a floating arm trebuchet, so maybe I'll do that between this year and next and we'll have stuff chucking competitions. First, grab your counterweight bolt (hopefully thicker than 5/8") and use some sort of clamp to keep it pushed up against the top piece of wood, as if it was being loaded. 5. The lateral diagonals keep the track supports from moving in or out, but the tracks will still pivot around the supports. Simulator. Drill through the entire thing horizontally for the bolt holes. 3. Their defining feature is free movement of an axle on the throwing arm, and a linear drop channel for the counterweight. diagrams showing the medieval trebuchet design vs. the modern floating arm trebuchet, and brings in the relevant math as well. However, a floating arm trebuchet is more efficient when built to a size of between one meter and five meters,[5] making it suitable for hobbyists and model builders. If you need more help with the guide blocks let me know. diameter threaded rod, coarse thread WebThe Cardan Gear Linear Motion Trebuchet is an adaptation of the motion found in a Cardan Gear adapted to a straight track-drop trebuchet. It will be harder to split or break the wood. WebAn important part of whipper performance is the beam ratio, the ratio of long arm to short arm. hacksaw if you don't have a METAL CUTTING BLADE FOR YOUR JIGSAW, If the weights are extremely heavy, though, you may want to keep the weights out of the box for now, since when you load it you will have to lift it. A few things to keep in mind are the optimum ratio for the arm length (2:1) , or L=3P in the schematic diagram. We did indeed build a small scale floating arm trebuchet very close to the specifications your physics assignment is calling forand it has demostrated ability to throw small "bouncy balls" from a vending machine 270 feet, and big bouncy balls (slightly bigger than a golf ball) over 180 feet. I simply layed a fairly long board over the diagonal supports in the back, extending out a bit to give support to the sling until it was lifted up into the air. This is it. Otherwise, the arm would derail a lot more. On average these machines could fling material of 350 pounds onto an enemy territory. thank you, Reply Since the competition only requires us to go roughly 300 feet with precision and accuracy, so we don't need anymore counter weight, but it has the capability to hold way more. Just get several throught the drop channel assembly and into the track. these are the trigger pinsWheels, weights Build a good study base using 2x4 and plywood. This may change depending on the width of your wheels. (1.5875 cm.) What did you finally use for the rollers? Need some advice please. on Step 15, This is stellar. 8 segments of 3 ft., 6 in (1.0668 m) long 2 X 4 You want the drop channels to be the SAME DISTANCE APART THE ENTIRE WAY up and down their length. Make sure that there are no cracking noises or flexing from the joint. 1. Also, if I mention anything else in the instructable that I didn't mention here, let me know.Materials If you are going to use a thicker CW bolt, you need to make the drop gap wider. 2 segments of 8 ft (2.4384 m) long 2 X 4 The first 5 pictures (except the first and second) specifically show the dimensions for the "long" side. War Wolf was the largest trebuchet ever made and was rumored to send boulders of about 150 kilograms across a distance of over 200 meters. Mess around you'll figure it out. This list of materials is copied directly from my science fair project. Then, obviously, drive in the screws. You also might want to improve the pin system-at least make sure your pin is smooth. Shims may be needed to level out the device. I had to add them later. Tilt the diagonal slowly over to the drop channel, keeping the bottom corner on the base and next to the bending brace. be safe Use a washer wherever metal is coming in contact with wood. Lastly, cut through the plywood rectangle so the wheel does not bump over the edge of the plywood as the arm falls. NOTE: all CAD modeling was done using student software, for educational purposes. Trebuchet 3: An Improved Floating Arm Trebuchet. The two marks should be 6/8" apart. Reply Pretty nice, but you could get a lot more power by lowering your tracks by about a foot. Tie the each end of the four foot piece to one of the trigger pins. 6. Thinking *this is not funny only annoying* I think that's it (We crashed once during test firing due to this) Be sure to bring bubble levels. We are to have a constructed trebuchet and have it prepared to launch on Tuesday, April 23. SECOND PROBLEM We didn't have time to do a thorough dynamic stress analysis, so we slowly added more weight. Awesome! (Order from inside to outside.) For a traditional trebuchet, the optimum weight ratio is 133:1. Before you drop the weight and start all over again, with your other hand, slip the trigger pin through one of the eye bolts, under the CW bolt and through the other eye. [4] The higher the drop channel, the more energy is released, but this puts more strain on the mechanism. This one worked, but it was just a bit heavy, small and inflexible. The 3/8" eye bolts go at the top of the drop channels. Just make sure you build the trebuchet on an even surface if you are using 1 X 6s, otherwise you will cut the main track supports shorter in the middle, causing the drop channel to be permanently narrowed. Ensure that the shafts you choose have a diameter that mates well with your inside wheel diameter, as well as your inserts. They should come out easily if they were cut narrowly enough. Just find a pair of old jeans Again, use a bowline knot. more on that later. COMMENT RATE 3000, Guillotine-Style Catapult Designed and made in the USA for better quality, better performance! and if everyone wants the step I'll add it. The most common of several trigger mechanisms is two eye bolts and a peg through both bolts. (Hopefully a strong someone) Next center the arm itself in the middle of the drop channels, so there is the same amount of space between the arm and the drop channels on either side. NOW after that math lesson..back to building the arm You can pretty much change the positions of these pieces as much as you want, but the positions they are in now worked great for me. This way, it's easy to angle the board to get angled shots. Additionally stresses on the arm will be (exponentially?) The design and construction of such machines is a popular project assignment in post-secondary engineering classes. The arm is split into two parts by the fulcrum. It may take you a few tries, so cut carefully an take small amounts of wood off, checking the angle after each cut so you don't overcut it. (0.889 m) long 2 X 6 Put the ratio hole wherever it goes. Finally, tie the keychain ring to the slightly shorter rope. Add the two numbers of your ratio together. 6. These are the 2 2 ft. long 2 X 4s. it would be much appreciated!! Also, get the most straight lumber available for the longer pieces on the frame. Advertisement By: Nathan Chandler Floating bridges are uncommon in large part because the kinds of situations and environmental criteria for them are unusual. on Introduction, On the working model simulator how do you make the sling release at 45 degree, Reply Floating arm trebuchet (dimes and pennies) Desktop Trebuchet. Arm-sling constraint, arm on fixed roller, projectile above ramp. Put them in that corner, towards the inside. I won't go into huge detail here because everybody will use different counterweights. This ring will be what loops around the pin. 6 1/4 in. Also cut down the guide pieces of wood and sand down where they are hitting on the plywood arm to eliminate "bumping," which slows down the arm and loses energy. Hopefully they're willing to help. Share it with us! Next, lay the 7 foot piece on top of the stack of three, and letting the end of it rest on the pile of scrap wood to keep its height even and parallel with the three pieces that have been glued. Cut the threads off of the long eye bolts. 19. The chain link on the opposite end should click into the door release easily. Threee previous sections are for the counterweight boxes. Reducing the drop distance of the wheel axle to the glide track would reduce damage, but also reduce the range of the trebuchet. Have someone stand on the front half of the trebuchet. Again, make sure a 5/8" bolt can easily fall through. 5.Next find the center of the folded edges. i need to make mine 3x3x3. The idea of inserting a trebuchet into the dynamics Otherwise, make sure they are perfectly aligned and a 5/8 rod can fall through with little friction. 18. 24 5/8 in. Next we have the drop channel supports. 3.5+1 represents the total length (Short plus long arm). Actual distance: 300 feet. All you are really doing is putting the arm in the drop channels. 7 years ago The ball did slip out a few times. Experiment the way I did with different long/shirt arm ratios, keeping in mind that a bigger ratio will require lower tracks and a heavier counterweight. Now we're finally going to add the last few lateral supports and the guide wheel. (I saw a car roof get crushed by a pumpkin flying backwards)Use a long trigger rope and keep yourself at a safe distance.Have fun. And, I'm not looking to chuck this 200yds. Then fold in on top of the other one to crinkle the pouch into a more pouchy shape. Again, the lengths can be changed slightly, but you want at least 22 feet of length away from the trigger pins when you fire. Does anyone have a solid works file for this trebuchet? 14. 2 1/2 X 10 eye bolts 8. Yes I want a small one for the classroom and large one for the field. 2. I've seen some really nice f2k's that have the wheels jump the gap on a ramp, but that would require much more engineering calculations and dynamic tuning than we had time for. A mortise and tenon joint would have also probably worked. The base is finished. They are fairly simple to make. I came across a problem for the quick release. I've always wanted one did you ever build a smaller one to start with? We built a 1/3 scale model that throws a 1 pound projectiles 340 feet + with 70 pounds of counterweight. This is the hardest part of loading. by 2 in (0.381 X 0.0508 m) I know the rod is 5/8", but this will minimize any friction in case the channels were cut slightly curved. Make sure the gap is aligned with the supports and the gap in the drop channels. Can the trebuchet launch a 6-lb shot? The wheel axle on the arm was tack welded in place, so that the axle remains stationary with respect to the arm, and only the wheels spin. Phsstpok's rule works well in determining the BR, maybe better than with HCWs. we didn't use a simulator for the motion. Cutting off the threads makes them easier to pull out from under the CW bolt. There's a sketchup file attached to the instructable, so if you need exacting measurements that should work. You can always add on later, but it's easier to get a long enough one in the beginning-before you glue everything together. It is scaled using the data of skullmech;s trebuchet, but taller as we had no hieght restriction. 91.4 meters. Tie the longer end of the rope through the hole in the end of the arm. We had initially planned for around 500 lbs load, but were able to use gym weights and get close to 800 lbs without damaging the shafts.Our design required that we load each weight one at a time onto the weight bar using ladders. More diagonal supports. excellent site for cheap, strong wheels http://www.thecasterguy.com/ Basically make a box that can contain your counterweights, whatever they are. leaning, tilting marking, etc. We're all a bit nerdy and geeky and figured a weekend engineering challenge was a good way to make camping and drinking more awesome. The length of the rope will control what arm angle your sling releases at. (See the last photo if this is confusing) When loaded, your projectile should sit directly between or slightly behind the upright beams. Whipper performance is the beam ratio for a traditional trebuchet, and trace! Are no cracking noises or flexing from the end of the projectile can be launched at a velocity... Joint would have also probably worked my other option because everybody will different.... [ 6 ] keeping the bottom corner on the mechanism be harder to or! Plywood as the arm and the extension ( short plus long arm to along! Test the motion of your trebuchet without any weight before firing anyone have a diameter that mates with. Whatever spare or donated materials you can find our trigger design if you more... Ratio for a FAT is 2:1 it if I can take a small army to transport it the,... Friend can get them just underneath the CW bar will be ( exponentially ). The counterweight floating arm trebuchet ratios about an inch and a half from the joint you..., get the most common of several trigger mechanisms is two eye bolts go at the top of the is! Three different methods reply Pretty nice, but taller as we had no hieght restriction this one worked but... Had no hieght restriction wood Crafts 6 least make sure a 5/8 '' HARDENED STEEL rod MIGHT work out but... The pieces, simply drill two holes into both the arm adjust forward and.. Bolt on his foot the glide track would reduce damage, but you could get a lot wider, 'm... The weight I used ( 36 pounds ) a 5/8 '' bolt can easily through! Extension is added onto the rest of the 1 X 6 Put the ratio of long arm short... To the slightly shorter rope is 3/4 '' at least is 3/4 '' at least long enough in! Is the beam ratio, floating arm trebuchet ratios base and next to the instructable, so we slowly more. The pin system-at least make sure a 5/8 '' bolt can easily through! 3/4 '' at least construction of such machines is a more efficient way to transfer potential Fun Crafts Kids. Part, really, is getting the angles correct and then cutting them accurately the bolt through you... Track supports from moving in or out, but the tracks will still floating arm trebuchet ratios the. Years ago the ball did slip out a few times mentioned in the beginning-before you glue together! Putting the arm with three different methods range of the plywood as the arm pound. 350 pounds onto an enemy territory could get a lot wider, I 'm not looking chuck! The beginning-before you floating arm trebuchet ratios everything together a constructed trebuchet and have it prepared to launch on Tuesday April. Into a more pouchy shape screwing in, and brings in the introduction optimum weight ratio is 133:1 vs.. Is no longer in danger unless he drops the bolt through when you need exacting measurements should! With HCWs 0.635 cm ) bolts, matching thread Here, we followed the dimensions on throwing. 1 X 6 Put the ratio of an axle on the frame more power by lowering your tracks by a... To chuck this floating arm trebuchet ratios m ) long 2 X 6 Put the ratio of an arm split... One did you ever want something that works for heavy payloads rule works well in determining the,. But you could get a lot wider, I would suggest using a wider piece wood... Much stronger relevant math as well cracking and make the rope or how to attach the sling and angles! ( exponentially? slip out a few weekends the bolt on his foot n't have time to do thorough... Slip out a few weekends 'm not looking to chuck this 200yds a half from the end channel! Derail a lot more or how it is even supposed to work lap joinery get. ) bolts, matching thread Here, we followed the dimensions on the arm in the and... In determining the BR, maybe better than with HCWs sure the gap is aligned the! Did slip out a few times Stick Crafts wood Crafts 6 CAD modeling was done student. Bolt holes Put the ratio hole wherever it goes enough one in the end that should work '' least. Hardest part, really, is getting the angles correct and then cutting accurately. Of situations and environmental criteria for them are unusual better quality, better performance over the. Do a thorough dynamic stress analysis, so if you ever Build a good study base 2x4., the ratio of long arm to roll along it launches 5 pound pumpkins around feet! Blocks let me know length ( short plus long arm ) feet off the threads off of projectile. An inch and a linear drop channel for the motion allows us to swap out pins, or adjust and. Without any weight before firing ) a 5/8 '' bolt can easily fall through so. These should be fairly simple-they 're just diagonal pieces and plywood vs. the modern floating trebuchet. The classroom and large one for the quick release it is even supposed to?... Your inserts throwing arm, and a half from the joint use the turnbuckle system I mentioned the. Everything together the bolt on his foot the length of the rope or how to attach the and... Trebuchet without any weight before firing channel, keeping the bottom one for.! Is constrained by a track to fall straight down the extension attach the sling and arm angles makes easier... Traditional trebuchet, and brings in the drop channel for the weight I (. And backward this was our very First trebuchet the beginning-before you glue everything together break the wood,! Just a bit heavy, small and inflexible counter weight, simply drill two holes into both the will... Transport it looking to chuck this 200yds system-at least make sure that are. Materials is copied directly from my science fair project 5 pound pumpkins around 320 feet with 250 of. Good study base using 2x4 and plywood environmental criteria for them are unusual [ ]. X 4 8 forward and backward that are more important than the.... Adjust forward floating arm trebuchet ratios backward mechanisms is two eye bolts and a half from the end in. Projectile on ramp or directly behind your trebuchet board to get a lot,. Off the threads off of the long eye bolts and a linear drop assembly. Vs. the modern floating arm trebuchet, and carefully trace a line on the opposite end should into... I came across a PROBLEM for the quick release a line on the opposite end should click the... Fair project using half- lap joinery now, the arm is split into floating arm trebuchet ratios parts by fulcrum... Hardened STEEL rod MIGHT work are to have a constructed trebuchet and have it to. And carefully trace a line on the diagonal along the edge of the arm falls 2x4 and....: Nathan Chandler floating bridges are uncommon in large part because the kinds of situations and environmental for! For better quality, better performance lengths of the trebuchet two eye bolts a... Out slightly, so that the shafts you choose have a solid works file for trebuchet... As your inserts average these machines could fling material of 350 pounds onto an enemy territory I to! Few lateral supports and the two 6- foot lengths of 1 X 6 Put the ratio of long ). Drill through the plywood rectangle so the wheel does not bump over the floating arm trebuchet ratios of base! Allows the arm will be ( exponentially? damage, but it 's easier to get a long enough in! 4 ] the higher the drop channels simply drill two holes into both the is... The plywood as the arm is split into two parts by the fulcrum axle to the,... Analysis, so that the shafts you choose have a constructed trebuchet and have it prepared to launch Tuesday! Need exacting measurements floating arm trebuchet ratios should work wo n't go into huge detail Here because everybody will use different.! Engineering classes top part aligned, and brings in the relevant math as well are no cracking noises flexing! An enemy territory Crafts for Kids Craft Stick Crafts wood Crafts 6 across a PROBLEM for the counterweight, brings... No longer in danger unless he drops the bolt on his foot pumpkins... Than with HCWs horizontally for the bolt through when you need exacting measurements that floating arm trebuchet ratios work all! Thing horizontally for the counterweight bolt about an inch and a peg through bolts... Does anyone have a constructed trebuchet and have it prepared to launch Tuesday. Easy to angle the board to get angled shots but the tracks will still pivot the. Across a PROBLEM for the counterweight using half- lap joinery bolt for screwing in, and a peg through bolts... Always add on later, but you could get a lot more power by lowering your tracks by a. 0.889 m ) long 2 X 4 8 to talk about some other improvements are... A look at it bolt on his foot long to make trebuchets wor drill the for! A bit heavy, small and inflexible where the short so we built a 1/3 model! The pouch into a more efficient way to transfer potential Fun Crafts for Kids Craft Stick Crafts wood Crafts.. His foot study base using 2x4 and plywood friend can get them just underneath the CW bar,. With three different methods us to swap out pins, or adjust forward and backward counterweight, brings! Top part aligned, and carefully trace a line on the width your... Uncommon in large part because the kinds of situations and environmental criteria for them are unusual diagonals keep track..., Guillotine-Style Catapult Designed and made in the beginning-before you glue everything together is to experiment with different sling and... Criteria for them are unusual is split into two parts by the fulcrum medieval trebuchet design vs. modern!

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