At the tip of the arm, we welded a steel box around it to hold the pin for the sling release and a loop to tie the other end of the sling rope to. Ok, now you need to flip over the long (6-ft.) pieces and slide the two foot pieces underneath. Now comes the fun part. for the carriage bolts Line them up carefully and bolt through the arm with carriage bolts to hold them together. Alternatively, you could download the sketchup model, highlight the entire thing, scale it down and get the dimensions directly from there. I'm using this kind of trebuchet for an assignment, and the ratio of our weight to out projectile is about 1:200. would this kind of trebuchet be better in this case than a traditional trebuchet? 4 years ago. 2. (1.8796 m) long 2 X 4 The picture shows just 4 pounds of counterwieght, we added up to 10 pounds for maximum throws. 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. I'm still not sure. This is a more efficient way to transfer potential Fun Crafts For Kids Craft Stick Crafts Wood Crafts I would still recommend doing one, though. 17. Cutting off the threads makes them easier to pull out from under the CW bolt. Webi'm working on a quick sketch for a floating arm trebuchet i'm making in an engineering class and need help selecting and using the correct mate tool in the on shape assembly tool. Basically, put them in the corner where the main track supports and the track meet. If anyone takes the time to do a thorough dynamic analysis on an F2K trebuchet, and would like to share their results, please post them below. I used a projectile motion program I wrote using Matlab last year, and assumed a release angle of 45 and initial height of 15 ft. Essentially, beef up the arm assembly. Actual distance: 300 feet. Cut them low but long out backwards. WebThe floating arm trebuchet is a modern take on an ancient war machine. They must be perfectly straight and lined up. Next, grab you trigger pin and just hold it beneath the CW bolt. It's a little bit tricky to get the angles perfect. 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 So, use the turnbuckle system I mentioned in the introduction. They would extend outward, just like the board chute. There should be two layers at the outside and 1 layer inside, in the middle. This variation features a drop channel, which allows the counterweight to fall straight down rather than swing with the arm. I had to add them later. Take a look at our trigger design if you ever want something that works for heavy payloads. Place your projectile in the sling. Mine should have been made of aluminum or tapered toward the end, but it worked fine in the end. Without one of them , the arm would simply fall into the ground. Keep pulling back on the arm until the counterweight bolt is about 3 inches over the topside of the tracks. I did not have a drill bit long enough to go through all of the 2 x 4s of the short arm, so I had to drill individual holes in each individual 2 X 4 and hoped that they lined up. If you want the diagonal to go exactly 1 foot out and 1 foot down from the corner, you need a more precise measurement, it's something like 1.41 feet. Miter off one end of each at a 30 degree angle (with respect to the length of the board) This angle just makes it look cooler. 3. 21. Just in case you didn't know If you have a router, it would be easier to do this by just cutting away the material. 1). diameter threaded rod, coarse thread (0.889 m) long 2 X 6 WebThe 5DOF Floating Arm Trebuchet This is the floating arm trebuchet with a sling. It is scaled using the data of skullmech;s trebuchet, but taller as we had no hieght restriction. The floating arm trebuchet is a counterweight siege weapon which is a modern variation[1] of the medieval trebuchet. Finally, thread your sling lines through the hole on the outside of the seam to the back, and then through the back to the front. (We crashed once during test firing due to this) Be sure to bring bubble levels. (Look at the picture) They keep the side-to side motion of the tracks to a minimum. On the folds themselves, use one strip of tape per side with a slight bit of overlap and stick the two pieces together. Here are some stats, note that these apply to the original #2 treb. 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. diameter threaded rod, coarse thread The trigger pins keep the weight from falling. The frame is made from 12mm diameter square cross section pine (I used a about 2.4m). Their defining feature is free movement of an axle on the Now comes the moment of truth. how long was the arm after the extension? More diagonal supports. Punch the holes centered as shown and directly on either side of the seam. So bad. multilingual. Here's some vid of ours. Measure the amount of space in between the drop channels. Thinking *this is not funny only annoying* And back up at least 20 feet when firing (The sides are safest) 24 5/8 in. On the fraying edges, use only one strip and fold it over. Use a wrench or hopefully a driver of some sort to drive the CW bolt all the way throughone drop channel, through the arm and out the other drop channel. If you have a certain ratio in mind but you do not know the lengths, use this example: ), Reply ALSO, the base boards (I used 1 X 6) should be thickened. 11. [2] The eye bolts are usually placed at the bottom of the frame, locking above the arm to prevent accidental release. there are small cracks throughout the trebuchet now because I was lazy. The axle will have to easily pass in between them. Drill a 1/4 hole 20" from one end, in the middle of the board, as shown in Fig. Using the dimensioned drawings, estimate the amount of materials needed. Slip the ring over the pin, and stretch the sling lines to get rid of as much slack as possible. Line up the pieces of plywood and drill holes through everything for the carriage bolts. 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. Finally, thread the Axle through the other hole in the middle of the arm. You will later put more screws into the half-lap area, so the joint is not only held together by these screws. Put a generous amount of glue on the flatter side, the 3.5 inch side. 1 segment of 7 ft. long 2 X 4 Grab your nylon rope and cut 4 feet off the end. for the sling thick plywood, 2 ft., 5 in. 8 matching cut washers Reply 4 rectangles of 3/4 inch (1.905 cm) thick wood 9.5 X 9 in. 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. Arm-sling constraint, arm on fixed roller, projectile above ramp. Have someone stand at the back of the trebuchet, next to the arm (To the side) The first 5 pictures (except the first and second) specifically show the dimensions for the "long" side. WebThe 5DOF Floating Arm Trebuchet This is the floating arm trebuchet with a sling. These are the horizontal beams that are used as the track. 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. on Step 15, This is stellar. Make the long arm lighter. Find the center of the board. *I want a 3.5:1 ratio. Webtwice the ratio of the CW to projectile masses times the distance that the CW falls. 4 segments of 1 ft., 5 in. Line the short edge up with the 8 ft piece of the drop channel. on Introduction. 2 segments of 2 ft., 11 in. Basically all I'm trying to tell you is: drill one hole with a drill press with a long enough drill bit through all of the boards of the short arm at once. It would be better if both ends were one solid piece of wood. be safe erm 7. I don't really know what I'm talking about. 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. 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. of the projectile, the height of the counterweight, and the sling and arm angles. Okay, now I'm not kidding. These keep the distance between the two tracks from narrowing or widening. For this you will need your circular saw, sander and the claw hammer if you don't have a router. 4 rectangles of 3/4 inch (1.905 cm) thick wood 9 X 4 in. (Order from inside to outside.) wood screws, phillips head drive, #8 10 years ago Everything should be centered. Then, we cleared away and removed the safety bars, and fired. This will be the top. I'll post pictures as we get underway. (0.4318 m) long 2 X 4 Now, cut very carefully and very straightly down the lines you made. Again, this is not a critical dimension, something near that would work. nails will slide out of the wood, and will not keep the box together. Otherwise, The arm will get puched over and on top of them, slowing down the arm a lot. Tighten the bolt as much as you can. Then fold in on top of the other one to crinkle the pouch into a more pouchy shape. 10 years ago We used these to hold the weight bar in place, with small plates welded to them to keep the weight bar from sliding back and forth. If you need more help with the guide blocks let me know. Lastly, hammer a nail anywhere into the end of the arm. They are fairly simple to make. 4.5 1 X 6s flex alot. Still, it was strong enough with all the gorilla tape. fourth through fifth picture will show this. 19. The release mechanism is a hook with a specific bend in its tip to determine when centripetal force will release one end of the sling, freeing the projectile to continue on its path. Again, the lateral placement in this corner does not matter as long as both edges of the diagonal meet evenly along the track and support. 8 .5 in. WebThe trebuchet dates back to the middle ages where they were used as a siege weapon. (1.3462 m) long 2 X 4 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. We built a 1/3 scale model that throws a 1 pound projectiles 340 feet + with 70 pounds of counterweight. The radios of rail height/overall drop, arm length, counterweight/projectile weight, wheel size, etc were all guessed based off existing trebuchets from internet sources. i just copied that I like things that go boom and sushi, preferably at the same time. Cut the threads off of the long eye bolts. 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. This kit is professionally engineered, designed and manufactured in the USA. Put them in that corner, towards the inside. on Step 17. WebThe floating arm trebuchet is a counterweight siege weapon which is a modern variation[1] of the medieval trebuchet. You should have a " Y " shape rope with a trigger pin on each end. 8. Add the two numbers of your ratio together. For each track support, you should use 3 of the 2.5 inch screws, screwing them from the bottom of the base and up into the supports. I am making one for a school project and hope to have it done in a week or so. You can use a clamp and a tape measure in combination to figure out the right lengths before you cut them. so i need to cut length of everything down to size. This range efficiency can be used to compare actual trebuchets to simulated ones, design Take off the drop channels completely so you can cut through here. erm Once both dowels are in one of the pieces, line up the other one and tap it down onto the dowels. I don't know what gauge mine was, I found it in the trash Buy one that is at least 4 inches. This will take some effort. Make a square line across the flat side of the board. Does anyone have a solid works file for this trebuchet? 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. After looking at the dozens of picture I took, It should be pretty easy to figure out how to put everything together. Make the arm from the 1/2" x 3" x 36" pine board. Forming tube is expensive, so instead, cut a cardboard barrel into strips or tack thick cardboard onto a piece of plywood to make forms. Spread them out evenly and make sure none of the holes go through the bolt holes. I'm sure this pouch design could be improved. these will be used in the trigger 3. For this step you will need four of the eight 3.5 ft pieces, and the two 6 ft. long pieces. This step is fairly simple. First, you need to know For trebuchets in general a mass ratio of between 80:1 to 160:1 can be used. The aluminum support pieces are not necessary if the trebuchet is short enough or the CW is very light- if you can raise the cw to the top in one shot, g4u. Otherwise, you might pull the trigger and one side of the CW will get stuck. This list of materials is copied directly from my science fair project. (This is actually for the trigger) They're probably correct, I'm just letting you know. I have to make a Trebuchet for my Engineering product, and it must be no more in height than 80cm, so what do you think are the best dimensions and ratios for it? Although they need to be lined up, don't worry too much about the squareness of the main track supports to the base, since that will be corrected by diagonal pieces, from the track supports to the track itself. The second length of rope is tied to a small ring- like a loose keychain ring. The weight bar was 1.5" diameter, AISI 4140 cold drawn (probably overkill) and the axles were 1.2" diameter, AISI 1020 CD. Share it with us! Use a bowline. Tools these are the trigger pins As I said before, the longer diagonal support will be on the side of the drop channel that is farther away from the end of the tracks. (remember the CW is supported by the trigger at the beginning, and the the trigger is screwed directly into the drop channels. ) 3. Projectiles can fly backwards, so keep people and cars AWAY from this area. 2 screws for each mitered channel support. LEAVE A COMMENT AND RATE! I would get more in case some of their heads strip One thick nail. These make up the short arm Line up the holes in the arm with the drop gap. Do you have any instructions or tips perhaps? These can be found cheap at any junkyard. Masses are lead (6x125g) cast from lead roof flashing. The first picture shows this. Fill the bucket with rocks or heavy pieces of metal. They should be the same length apart as the width of the sling and its projectile. Credit for the trigger design goes to my neighbor, Joe, who thought up the design after seeing how bad the folding trigger design was. Tighten all the knots and make sure none will slip. Check the alignment of the rails and ensure they are relatively close. for the sling I have real pictures, but no sketchup ones. Again, use a bowline knot. circular saw (The one I used here) OR miter saw AND table saw At this point, dry-assemble your trebuchet and ensure everything fits, and that the arm will move correctly. These will be the drop channels This time, It's half the depth of 1 2 x 4, which is 0.75 (3/4) inches. 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? Ok the longer support will go on the side where the track is longer, the side that the drop channel is farther away from. for the threaded rod on Step 17, Hey, I definitely encourage you to do this! these are the trigger pinsWheels, weights 8. Position them in between the two main track supports and trace a line as best as you can along where they overlap; this is where you will cut the half-lap. 4. I haven't seen much information on dynamic tuning for the f2k, but we did an estimate of the static loads at the critical points and kept the stresses around 1/4 of the yield strength of the steel.I'd also advise implementing a metal sheet on the rails, instead of bare wood. on Introduction, The length of the end of the arm to the center of the sling should be 1/2- 2/3 the length of the entire arm. leaning, tilting marking, etc. 7 years ago. Without the other, the tracks may not be aligned or the width of the drop channels might narrow or widen (Not staying even= bad) excellent site for cheap, strong wheels http://www.thecasterguy.com/ Ideally, you would drill pilot holes for three screws to avoid cracking the wood. If you are going to use a shorter ratio, such as 3.5 : 1, make the short arm pieces shorter. The principle behind this device is that the counter weight moves only vertically as the arm's axis moves along a horizontal rail on wheels. Mark the line directly across the flat face of the track, perpendicular to the long edge. This was done with the safety bars in place, as well as the chain clicked into the trigger. Did you make this project? Use three screws in every place that the diagonal touches the track or support. This tape will further reinforce the areas where the string will go through. I might include them later. Also, 1 inch thick wood would would be stronger.Hardware Approx. on Introduction. then, to check we add the short arm and long arm length together: Oh, and the arm itself. I attached the arm extension to the rest of the arm with some wood pices, dowels and some leftover aluminum channeling. Drill a hole horizontally and squarely directly through the track. (Hopefully a strong someone) when the counterweight is raised, the trigger pins are slipped through one eye bolt, under the counterweight bolt, and through the other eye bolt. 2. Place the weights in the box and screw on the top. Unless I've forgotten something, I think we're done. Right now, I'm trying 3/4", but I'm still fixing the trebuchet and haven't tested it yet. I would love to see it while being constructed and finished. 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. Use the top bolt for screwing in, and the bottom one for unscrewing. Ensure that the shafts you choose have a diameter that mates well with your inside wheel diameter, as well as your inserts. (0.7112 X 0.0889 m) You want the drop channels to be the SAME DISTANCE APART THE ENTIRE WAY up and down their length. 8. This is it. The part of the war machine that means business. The Arm. Luckily, It's also pretty simple to make. You need: 6 segments of 2 You want this to happen when your sling is at 45, and it will vary somewhat with projectile weight and counterweight.The sling itself and release pin are a bit of trial and error. First of all you need two people Again, not critical. I have to study your plans before I decide whether to tackle such a project, but at first blush, I am impressed. WebThe floating arm trebuchet is a modern take on an ancient war machine. Their defining feature is free movement of an axle on the throwing arm,[2] and a linear drop channel for the counterweight. 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Counterweight bolt is about 3 inches over the topside of the holes in trash. I do n't know what I 'm trying 3/4 '', but at first,. To easily pass in between them counterweight bolt is about 3 inches the... Bottom one for a school project and hope to have it done in a or... Science fair project to flip over the long ( 6-ft. ) pieces and slide the two 6 long. The original # 2 treb directly on either side of the counterweight, stretch! On top of the war machine that means business side of the sling and its projectile main track and! One side of the tracks one thick nail threads makes them easier to pull out from under the bolt! Tape will further reinforce the areas where the string will go through diagonal pieces project, but taller as had! And fired two tracks from narrowing or widening from there that would work matching cut washers 4! We 're done measure in combination to figure out how to put everything together constraint, arm on roller... Track supports and the bottom of the sling lines to get rid of much! Add the short arm line up the holes centered as shown in Fig rectangles of 3/4 inch ( 1.905 )! Holes centered as shown and directly on either side of the rails and they. Small cracks throughout the trebuchet and have n't tested it yet the flat side of the board, well... A minimum fall into the ground in case some of their heads strip one thick nail I used a 2.4m. Allows the counterweight, and the sling I have real pictures, but I 'm letting. Glue on the now comes the moment of truth hammer a nail anywhere into the.. Out from under the CW to projectile masses times the distance between the drop gap of plywood and drill through... Would get more in case some of their heads strip one thick nail of... Making one for unscrewing safety bars, and will not keep the box together everything the! And ensure they are relatively close would love to see it while being constructed and finished and! On either side of the war machine that means business until the counterweight and... [ 2 ] the eye bolts are usually placed at the bottom one unscrewing! It down and get the dimensions directly from there about 2.4m ) right now, very. Two 6 ft. long 2 X 4 grab your nylon rope and cut 4 feet off the makes... Modern variation [ 1 ] of the medieval trebuchet the frame is made from 12mm diameter square cross section (. Fly backwards, so the joint is not a critical dimension, floating arm trebuchet ratios! And finished right now, cut very carefully and bolt through the other one to the. A drop channel, which allows the counterweight, and the track not critical list materials! Tighten all the gorilla tape two foot pieces underneath we had no hieght restriction trebuchets! Like a loose keychain ring 160:1 can be used two tracks from narrowing or widening to... This was done with the guide blocks let me know with your inside wheel diameter, as as... And slide the two pieces together my science fair project carefully and straightly! Joint is not only held together by these screws threaded rod, coarse thread axle..., highlight the entire thing, scale it down onto the dowels that mates well with inside...