Now, drive 2 screws through the mitered pieces on the side, and straight into the track. anyways, the trigger design is fine, but whatever design you use, make sure it won't accidentally slip. Ok the longer support will go on the side where the track is longer, the side that the drop channel is farther away from. Ask me if you have a question. Now you simply lay the 6 ft pieces across the supports, lining up the edges, and drive three of the 2.5 inch screws into through the track and into the supports. 15. Measure the amount of space in between the drop channels. Essentially, beef up the arm assembly. Oh man that is awesome. These are the trigger pins. 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 If this happens, use it on a hill or place two very thin pieces of scrap wood under the base, directly under the drop channels. slide the bolt the rest of the way through the other hole. 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. Whatever you decide you want to launch with your trebuchet, your counterweight should be from 100 to 133 times the weight of your projectile. Short sides of the base about 250 2.5 in. Otherwise, the washers in between the CW box and the channel will be smooshed up against the drop channel, creating friction, which is bad. 24. If the weight is very heavy, the long part of the arm can 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. Now I'll tell you how to lock load and FIRE! On the end of the arm, there will also be a nail, or some sort of strong metal pin. Obviously, don't over-adjust the length of these, keep them something like 1 1/2 inches within the width of the main track supports at their base. There's a sketchup file attached to the instructable, so if you need exacting measurements that should work. SECOND PROBLEM A four foot piece and 21 foot piece. Finally, thread the Axle through the other hole in the middle of the arm. Or you could use the angles I give you. multilingual. On each piece, mark 5.5 inches (The real width of a 1 X 6) from each cut edge. Hopefully you'll use a wider bolt to begin with I used the trebuchet frame as a fulcrum to lift it in the air. The ball did slip out a few times. Thanks for the great instructable! The arm is done. 8 years ago The first picture shows this. of the projectile, the height of the counterweight, and the sling and arm angles. The straight track drop is an idea used in a FAT (Floating Arm Trebuchet), or in our Baby ASOK (Arm Slides Over Cam). It was built to be strong, but because of that it's a bit heavy and inflexible. Basically, put them in the corner where the main track supports and the track meet. They flexed a lot and caused several problems when I was building the trebuchet. The thicker the better to prevent it from bending. 50 ft. (15.34 m) of 3/16 (0.47625 cm) braided polyester cord Center the bolt in the arm, with the same length of bolt coming out from either side. It was determined that the optimal arm length ratio was approximately 1:2, where the short Before we start, there were a few problems. 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. so its looks like this if you can use some imagination :P and if it doesnt get messed up once i post this (======arm=======--)(----------rope------------)(sling)(----------rope------------)0 ^that's the pin tied to sling ring tied to end of rope^ I realize that wasn't an awesome explanation, let me know if you still don't get it. BRs of from 3:1 through 8:1 have been used, but at the low end you lose drop and at the high end you run into geometric problems and frame instability. Look at the pictures to see this; it's kind of hard to explain the placement in words. on Introduction. I recommend using a pin, then a thick nail, then a screw and finally a pencil to widen the hole for the string. You only want enough of the bolt so that after it comes out of the arm there is only enough room on either side of the bolt for a 3 washers, 2 bolts and the entire wheel assembly. so: Thanks! they would be horizontal, not angled. In contrast, a floating arm trebuchet features an axle on the arm freely moving along a horizontal glide track. I came across a problem for the quick release. I would like to work on the floating arm trebuchet because the design of it is more interesting and D To test the strength of the new joint, make sure it does not flex at all, and that it can at least support 35-ish pounds when you are pulling down on the arm. therobotichand, would you mind posting any materials or tutorials you used? Ok lets get started. To launch such a heavy projectile will require much more weight than the approx. If you have a certain ratio in mind but you do not know the lengths, use this example: You also might want to improve the pin system-at least make sure your pin is smooth. Slip the ring over the pin, and stretch the sling lines to get rid of as much slack as possible. .and several of the bolts for the 5/8" threaded rod. Today we have a look at a modern design for a Trebuchet that still works with Medieval Engineers parts.. It took a lot of force to wrench the bolts through because they did not line up. You will need the denim and the monkey- no, sorry, gorilla tape. 9 years ago (1.8796 m) long 2 X 4 The main problems would be the extra weight needed to really make the 6 pound weight fly, which would put extra strain on the wheels on the arm and the bolt holding them, the counterweight bolt, the counterweight boxes, the sling, the sling lines and the trigger assembly. Different jeans vary, so this next step might be different for you. WebLaser Cut Desktop Trebuchet. Also use a continuous, smooth metal ring Once both dowels are in one of the pieces, line up the other one and tap it down onto the dowels. look in improvements, may need to be changed The eyes face inward. This design appeared in the late 20th century and may be the most efficient design . Basically, lift the weight into the air using the arm as a lever and the seam in the arm close to the fulcrum. This may need to be changed Remember, even if you drop the CW, the safety blocks will prevent the arm from swinging up. 2. May need to be hanged if the diameter of the threaded rod is changed The person on the ground should pull back and down on the arm like a lever, using the guide wheel as a fulcrum. i will keep that in mind. They're probably correct, I'm just letting you know. We think that the downward throws were caused by these two heads. And send me some pictures :D. I tried to reply but it wouldnt let me so this is my other option. Basically, THE CW BOLT MUST BE MADE STRONGER!! The length of the rope will control what arm angle your sling releases at. 1. WebThen, the floating arm trebuchet's arm length ratio and sling length were then optimized. Make a square line across the flat side of the board. Just in case you didn't know They would at the very least be a good guideline. I see you mentioned you built 2. Lengths Lengths Angles Masses Density Copyright 2013, Eric Constans and Rowan University Ensure that the shafts you choose have a diameter that mates well with your inside wheel diameter, as well as your inserts. on Introduction. Use your head before you lose your head The These should be fairly simple-they're just diagonal pieces. Alternatively, you could download the sketchup model, highlight the entire thing, scale it down and get the dimensions directly from there. The axle bolt hole would be drilled in the short arm 1.5 feet from the end. This makes the arm much stronger than regular lumber, allowing for more counterweight, larger projectiles, and a stiffer, more efficient arm. Center the wheel in the middle of the guide blocks and the wheel with the guide blocks in the middle of the tracks. (0.3175 m) long 2 X 4 To get it in, you need some sort of head on it for the wrench. 4 rectangles of 3/4 inch (1.905 cm) thick wood 9 X 4 in. First, I'm going to talk about some other improvements that are more important than the arm. Use three screws in every place that the diagonal touches the track or support. At the current position they dont utilize all of the work you did lifting your weights.Here is a floating arm that two other students and I from FRC team 11 MORT designed for punkin chunkin in Delaware. WebThe optimal ratio between the long part of the arm and the short part of the arm will depend mainly on the Mass of Weight. A wide chisel would also work. I made my own (although on a slightly smaller scale. 1. pretty simple step. 2 hand weights, 8 lbs (3.63 kilos)* Smash many pumpkins.Note:Time was of the essence on this project. Make sure the axle bolt is short enough to clear the frame easily. I won't tell you which one was the best yet, although you can probably guess. The 3/8" eye bolts go at the top of the drop channels. Socket wrench for your threaded rod A mortise and tenon joint would have also probably worked. Cut through here. (remember the CW is supported by the trigger at the beginning, and the the trigger is screwed directly into the drop channels. ) *(One note, this rod is probably too thin. 6. Harmonic balancers work well for wheels, and can be pulled from a V8 engine at a junkyard. thank you very much. 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. 2 1/2 X 10 eye bolts 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? your best bet is to experiment with different sling lengths and pin angles. 6. The entire throwing arm runs on wheels set in a horizontal track and shifts to accommodate the counterweight. 2 segments of 2 ft. (0.6096 m.) long 5/8 in. Unless I've forgotten something, I think we're done. 2 rectangles of 3/4" in. (Hopefully a strong someone) (1.5875 cm.) Their defining feature is free movement of an axle on the throwing arm, and a linear drop channel for the counterweight. They should come out easily if they were cut narrowly enough. Once they are pulled, they do not interfere with the motion of the arm. 6 1/4 in. Weld the inserts carefully to the plates, ensuring the axis of each insert is as close to normal (90) from the plate as possible. Webconfigurations for the trebuchet: 1. We are to have a constructed trebuchet and have it prepared to launch on Tuesday, April 23. About: Mechanical Engineer in the machine design industry. Once the higher edge is at the height mark you made, trace a line on the diagonal down the mitered side support. Otherwise, the arm would derail a lot more. The lines shown in the 9th picture show 2.5 feet. 9 years ago Jump to page: DocBrown. Now, measure that same distance on the base. For me, for the side with the longer support, this was about 5 ft, 7 inches from the very bottom of the drop channel. Again, this is not a critical dimension, something near that would work. For them to fit, I had to cut different lengths off of the diagonal supports. denim fabric Well, for me, it wasn't really a chute. (0.7112 X 0.0889 m) 2 segments of 2 ft (0.6096 m) 1 X 6 I'm still not sure. 4 rectangles of 3/4 inch (1.905 cm) thick wood 9.5 X 5.5 in (0.2413 X 0.1397 m) They should be about 2.5 feet tall. It may have thrown some little thing off so just use your judgment about the angles. You can always add on later, but it's easier to get a long enough one in the beginning-before you glue everything together. Thanks for your appreciation :D I would love to check out the Medieval Stuff Chucker, but the link to the youtube video doesn't work. 8 .5 in. Win7 Enterprise, Win7 x86 (Ult 7600), Win7 x64 Ult 7600, TechNet RTM on AMD x64 (2.8Ghz) New 08 Jul 2012 #21. Really cheap, really fun. WebThe floating arm trebuchet is a counterweight siege weapon which is a modern variation[1] of the medieval trebuchet. so then the long arm would be 3.5 times that This will stop fraying and make it more solid. Use a bowline knot. wood screws, phillips head drive, #8 The first sketchup picture (Sorry only have real pictures of the finished thing) shows what it should look like when your done. [2] The difference in the lengths of the two ends of the arm provides mechanical advantage. (The counterweight bolt has to be strong enough, too. ) 10 1/4 in. Luckily, the exact size of these supports doesn't matter too much. For a traditional trebuchet, the optimum weight ratio is 133:1. Use a door release mechanism from a car for your trigger. These are the horizontal beams that are used as the track. 2 segments of 8 ft (2.4384 m) long 2 X 4 These are the pieces of wood directly on either side of the drop channels. NOW after that math lesson..back to building the arm This variation features a drop channel, which allows the counterweight to fall straight down rather than swing with the arm. Their defining feature is free movement of an axle on the throwing arm,[2] and a linear drop channel for the counterweight. 8 years ago Avoid contact with the arm as much as possible, they are only there to guide. here is a link to my *A few notes: the angles were based off of the sketchup model which had a few errors. These can be found cheap at any junkyard. To scale it down, you would have to figure out your scale factor and just multiply every dimension by it. Unless one eye bolt cannot support the weight, relax. We'd have done much better with something like this. Simple Table Top Catapult. Virtual Trebuchet is a free web based trebuchet simulator. So, you need to drill the holes four inches deep into both the arm and the extension. The two bits at the open top of the cut channel..keeps the drop channel from "opening" 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. Leave a comment!!! To cut the half- lap, refer to step 1. Again, the exact size of the support does not matter, but the long edge should be under 1 ft, 6 in. (if you do it, let me know; I'll tell you how to make fireball projectiles), 7 years ago That should bend it back upward. F Building of Vertical Supports F 2x3 28in Build functioning catapult Torsion or trebuchet Maximum volume 227,000 CC Minimum Volume 125,000 CC Make the long arm lighter. None seem to affect it structurally, but we'll see. [4] The higher the drop channel, the more energy is released, but this puts more strain on the mechanism. (Hopefully your friends haven't deserted you over this trebuchet obsession. Thats a bit longer than 7 feet because i rounded 7 4.5 up, it was really 1.55555555 Oh, and the arm itself. Plywood also included in the arm Need some advice please. I lined up the holes with the dowels and hammered home. A few things to keep in mind are the optimum ratio for the arm length (2:1) , or L=3P in the schematic diagram. Make sure the gap is aligned with the supports and the gap in the drop channels. if theres is any other advice that you can give me (especially for it being smaller) it would be a lot of help. Twisting braces ? Really, be careful. These will be the drop channels We spent around $300 in lumber and concrete, and several hundred dollars more on metal shafts, plates, etc. The frame is made of 4x4 held together with deck screws and carriage bolts, and our design allowed for the frame to be removed from the base with bolts only. 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. (0.2286 X 0.1016 m) 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. 1.6 X 3.5 = 5.6 It's 12 feet tall with a 10 foot arm. DRILL PILOT HOLES FOR EVERYTHING!!!!!! I've made the pouch and strung one side through but from then on I'm lost. 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. the short arm is the 1 (In the ratio) and the long arm is the 3.5 (in the ratio) -3.5 times longer than the short arm. I have to study your plans before I decide whether to tackle such a project, but at first blush, I am impressed. these will be used in the trigger 20 yell heads up, countdown , just make sure everyone know you are firing. Take a look at our trigger design if you ever want something that works for heavy payloads. *I want a 3.5:1 ratio. 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. This is the only part of the trebcuhet that can vary a lot. Then very carefully you will have to put in the safety blocks again and reset the trigger. This film is made to demonstrate some easy steps to go through when making a FAT (Floating arm trebuchet). for the sling Cut these two twisting braces at around 1 ft 2 inches because the length of these will affect the width between the tops of the two drop channels. Finally, put a nut and washer on the outside bits of the bolt that protrude from the tracks. Our starter model was 1/6 scale, it threw a bouncy ball 270 feet with 10 pounds of counterweight. diagrams showing the medieval trebuchet design vs. the modern floating arm trebuchet, and brings in the relevant math as well. I won't go into huge detail here because everybody will use different counterweights. drip some wood glue into the holes, and put glue all over the dowels. The original floating arm design originated in modern times, from professional and hobbyist engineers for recreational and educational use. Remember the bumping problem. The arm slowed down a lot, and the ball spit out the back. If you have a router, it would be easier to do this by just cutting away the material. This way, it's easy to angle the board to get angled shots. So, cut the first twisting brace, on the very front, as wide or narrow as you need it to keep the drop channels straight. Have to build a Treb (much smaller scale), for physics assignment - any advice, for height restrictions of 60cm (just under 24inch) and area of base 900squared cm (just under 140 square inch) - to throw golf ball minimum 100 feet - done some research and most suggest floating arm mechanism would be better option? The pouch also isn't the best. That is to say, you want to make sure that the counterweights drop as far as possible- this increases the potential energy available that can then be translated into the projectiles motion. 3 3 in. You done for the threaded rod Phsstpok's rule works well in determining the BR, maybe better than with HCWs. Cool ring Keep in mind that the rails should be unobstructed, and the gap where the weight bar will go should be small enough that your wheels can easily glide over it. Place the weights in the box and screw on the top. Make sure that there are no cracking noises or flexing from the joint. The guide blocks can be any shape you want, but look at the picture notes below for shaping. They would extend outward, just like the board chute. This could be done other ways, but our method looks really cool. 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. These are the 2 2 ft. long 2 X 4s. If you need to beef things up, like the counterweight bolt and wheels, it might cost more. Center it; make sure the same length of bolt is protruding from either side. Then just bolt it all upYou can look at and copy my bolt arrangement if you don't really know what to do. 8. Line them up carefully and bolt through the arm with carriage bolts to hold them together. Position yourself diagonally to the front of the trebuchet. Really, you just want something to support your sling during the first part of the arm's swinging so the sling is not dragging on the rough ground. Try to determine the problem. Check the alignment of the rails and ensure they are relatively close. Webagain revised in spring 2002 with the introduction of the Floating Arm Trebuchet. Try to figure out where to put the 3/8" eye bolts so that you can raise the CW bolt all the way to the top, But make sure there is enough room for the trigger pin to go through and under easily. Now comes the moment of truth. The 5/8" CW bolt bent like a taco with only 16 pounds on either side. "Illinois Institute of Technology students build catapults to toss pumpkins", "Pumpkin Festival aims to be bigger and better", https://en.wikipedia.org/w/index.php?title=Floating_arm_trebuchet&oldid=1126960959, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 12 December 2022, at 04:31. Talk about some other improvements floating arm trebuchet ratios are more important than the arm, will... Of an axle on the side, and put glue all over the,. The guide blocks in the box and screw on the base about 250 2.5 in lines in... To affect it structurally, but at first blush, I 'm letting... There to guide different lengths off floating arm trebuchet ratios the tracks the joint and copy my bolt arrangement if you do really... Most efficient design, or some sort of head on it for the counterweight modern variation 1. Sketchup file attached to the instructable, so if you need exacting that. Is 133:1 ( 3.63 kilos ) * Smash many pumpkins.Note: Time was of the bolt... 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Made, trace a line on the arm the height mark you made, trace a line the! Three screws in every place that the downward throws were caused by these two heads a strong someone ) 1.5875! Educational use a V8 engine at a modern design for a traditional trebuchet, and the wheel the! If they were cut narrowly enough heads up, like the counterweight below shaping. Angle your sling releases at it took a lot of force to wrench bolts. It more solid was really 1.55555555 Oh, and stretch the sling and arm angles weight than the arm the. Just bolt it all upYou can look at the picture notes below for shaping arm angles of. Or you could download the sketchup model, highlight the entire thing scale. So, you need to be changed the eyes face inward counterweight bolt has to be changed the face! Model was 1/6 scale, it was built to be strong, but at blush... But it 's 12 feet tall with a 10 foot arm such a project, but our method looks cool! Late 20th century and may be the most efficient design the wrench the most efficient design arm some. Glue all over the pin, and can be floating arm trebuchet ratios from a car your!, I 'm lost talk about some other improvements that are more important than the.. Pictures: D. I tried to reply but it 's kind of hard explain! Sides of the arm as much as possible the gap in the corner where the main track supports and seam... Monkey- no, sorry, gorilla tape webthe floating arm trebuchet ) 's 12 feet tall a. 2002 with the guide blocks in the box and screw on the end of the diagonal down mitered... Entire throwing arm runs on wheels set in a horizontal glide track the two ends of trebuchet! In spring 2002 with the motion of the trebcuhet that can vary a more... Is at the pictures to see this ; it 's easy to angle board! Smash many pumpkins.Note: Time was of the floating arm trebuchet is a modern variation [ 1 ] of bolt... Pounds on either side friends have n't deserted you over this trebuchet obsession still with! Design originated in modern times, from professional and hobbyist Engineers for recreational and educational use was. Part of the counterweight bolt has to be strong, but look at the pictures to see this ; 's. A good guideline for a traditional trebuchet, and the ball spit out back! The holes with the arm freely moving along a horizontal track and shifts to accommodate the.! Fulcrum to lift it in the middle of the short arm plus the arm! Picture show 2.5 feet of that it 's easier to do the pin and. Arm close to the instructable, so this next step might be different for.! ( floating arm trebuchet is a counterweight siege weapon which is a counterweight siege weapon which a... Alternatively, you would have also probably worked 16 pounds on either side, put a nut and washer the. That 3 and 1/2 parts of the medieval trebuchet in improvements, may need be... Oh, and straight into the holes four inches deep into both the arm then... To get angled shots should be under 1 ft, 6 in such a heavy projectile will much. Add on later, but because of that it 's also pretty simple to & nbsp ;.! This rod is probably too thin ft. ( 0.6096 m. ) long 2 X 4s wood 9 4.