[5] Friction of the wheel on the arm axle against the glide track should be managed in a similar way. But I'll try. Use your head before you lose your head. [2] This causes the wheel on the axle of the arm to impact the glide track,[2][8] which is usually held steady with strong support beams. Drill through the entire thing horizontally for the bolt holes. 3 ft. (0.9144 m.) long 5/8 in. It would be better if both ends were one solid piece of wood. This is it. *(One note, this rod is probably too thin. These go in the front. the beginning Ok, so this is what the entire bulk of the trebuchet rests on. 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. The Floating Arm Trebuchet The trebuchet is a medieval gravity powered engine of siege warfare designed to hurl a projectile, such as a heavy stone or a diseased animal, at a distant target such as castles. To get it in, you need some sort of head on it for the wrench. -Use screws! 2 rectangles of 3/4" in. The Cardan gear was invented to accept linear motion from a steam piston to create circular motion. What did you finally use for the rollers? The so i need to cut length of everything down to size. Ensure that the tension will be applied in a direction that is similar to the way it is intended to be used in a car door. 5. Angle iron or steel sheet would work. 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. By tightening these outside bolts, you can change the alignment of the tracks and narrow or widen the distance between the drop channels. Ok, now, the base is constructed using half- lap joinery. when the counterweight is raised, the trigger pins are slipped through one eye bolt, under the counterweight bolt, and through the other eye bolt. This will prevent the counterweights from falling. 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. Approx 25 ft. (7.62 m)1/2 braided nylon rope 2 1/2 X 10 eye bolts I'm still working on the "improvements" page but everything I was going to mention on it was kind of already mentioned throughout the instructable. 2. Ok, so this is what the entire bulk of the trebuchet rests on. It's 6 feet long and 2 feet wide. And it is constructed with 1 X 6s That's its fa Lengths Lengths Angles Masses Density Copyright 2013, Eric Constans and Rowan University We made ours so that the chain had a tiny bit of slack in it initially, which we took out by tightening the nut on the eye bolt each time we fired. 7. To reduce friction of the sling on the launch track, the track should have a smooth surface.[5]. 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. Just find a pair of old jeans 2. After a certain point, the drop channel 2 X 4s will have to be made thicker so they can still hold up the CW. I'd look around on YouTube and compare different sizes of trebuchets. Ok, looking at the main pictures, there are two more big things that need to be added to the mainframe. again for the threaded rod The trigger is a fairly simple design. Not a big deal, but if you want them to be the same height as the ones here, then you need to change the angle of the diagonals. Our weights were 18" diameter and 4" thick, weighing 80-90 lbs each. I would still recommend doing one, though. These are the trigger pins. Share it with us! Beside the arm when it's at rest, these two channels are the tallest point of the trebuchet. I don't really know what I'm talking about. Please help because this project is due the 20th. Spread them out evenly and make sure none of the holes go through the bolt holes. the base When the trebuchet is placed on an uneven surface, the base will sag into whatever dip or bend upwards because of whatever hill. Always stand way back from the trebuchet, and keep the safety blocks in place until you are ready to fire. You will need the denim and the monkey- no, sorry, gorilla tape. For the trigger you will need the: Reply 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. Now comes the moment of truth. So we built a 10 throwing arm trebuchet. 24 5/8 in. ), but I came up with distances reasonably close to the actual performance. Basically, THE CW BOLT MUST BE MADE STRONGER!! Circuits | Floating Arm Trebuchet : 7 Steps (with Pictures) - Instructables WebVirtualTrebuchet is a web based trebuchet simulator that will allow you to quickly evaluate different trebuchet configurations. At this point, dry-assemble your trebuchet and ensure everything fits, and that the arm will move correctly. A pair of wheels allows the arm to roll along 2 segments of 2 ft. (0.6096 m.) long 5/8 in. While this is happening, the wheel is moved backwards by the torque acting on the arm from the counterweight. Sorry I haven't responded until now. 4. So now we're going to add some extra supports that will prevent the 2 ft 1 X 6 from bending, Lateral support and extra track support. 1. Bending That model was equipped with a folding gantry and pulley system to raise the counterweight, with that it could be fired every 2 minutes. [5], The dropping of the counterweight forces the arm to swing to one side of the glide track and quickly jerk in the opposite direction to launch a projectile. You will later put more screws into the half-lap area, so the joint is not only held together by these screws. The picture shows just 4 pounds of counterwieght, we added up to 10 pounds for maximum throws. The straight track drop is an idea used in a FAT (Floating Arm Trebuchet), or in our Baby ASOK (Arm Slides Over Cam). Maybe the wood "stretched" and then was kept in place as the glue dried. FDM 3D Printing; SLA 3D Printing; Also, the box needs to have a top so the weights don't come flying out when it reaches the bottom of the drop. (1.5875 cm.) The arm can be longer than your sheet of wood, but make sure the gaps between the pieces are in different spots for each layer. 3 ft. (0.9144 m.) long 5/8 in. 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. They should be about 2.5 feet tall. (Hopefully a strong someone) Try to have all the sizes of your shafts and designs for your trigger and sling release figured out at this stage, as well as how you plan to attach the shafts (welds or flanges, etc). 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. diameter threaded rod, coarse thread Finally, put a nut and washer on the outside bits of the bolt that protrude from the tracks. This range efficiency can be used to compare actual trebuchets to simulated ones, design Be sure to test the motion of your trebuchet without any weight before firing. 2. First, pick one end of the trebuchet to be the back. 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. From this line and out to the edge, cut 3/8" deep (Half the depth of a 1 x 6) with your circular saw every 16th of an inch or so, all the way across the flat side. I like the adjustable arm ratio. Then just bolt it all upYou can look at and copy my bolt arrangement if you don't really know what to do. Use a forstner bit or any other drill bit and drill holes parallel to the length of the long 1 X 6 and near the inside corner. Heavier projectile= earlier, lighter projectile = later. ) 4 years ago. The bottom is the side where the 2 ft 1 X 6 overlaps the long 1 X 6. The 5/8" CW bolt bent like a taco with only 16 pounds on either side. (Forward to the direction of motion makes it release later, backwards= release sooner. 7 years ago 8 years ago Other than those, there haven't really been any problems with the frame. anyways There's tons of assumptions involved there (what's the drag coefficient of a pumpkin? Otherwise, make sure they are perfectly aligned and a 5/8 rod can fall through with little friction. This makes the arm much stronger than regular lumber, allowing for more counterweight, larger projectiles, and a stiffer, more efficient arm. WebThe floating arm trebuchet is a modern take on an ancient war machine. I will be modeling my trebuchet after your and would like to know Can the trebuchet launch a 2-lb dumbell? Remember, even if you drop the CW, the safety blocks will prevent the arm from swinging up. I would love to see it while being constructed and finished. WebThe 5DOF Floating Arm Trebuchet This is the floating arm trebuchet with a sling. Ask Question Comment Download About: Mechanical Engineer in the machine design industry. This way, it's easy to angle the board to get angled shots. (Diagonally). The guide blocks can be any shape you want, but look at the picture notes below for shaping. These Are not included in the instructable because I did not think they were necessary. Ok the longer support will go on the side where the track is longer, the side that the drop channel is farther away from. here is a link to my 8 years ago. Untangle the ropes and walk the long one out its length to the front and side of the trebuchet. Awesome! The box should have a bottom that is "outside" the walls, screwed in from this bottom and into the walls, not through the walls and into the bottom. Short arm, washer, bolt, washer, wheels and bearings, washer, bolt. (2.54 cm.) [9] These machines and their designers are frequently to be found competing in various recreational events, for example, pumpkin chucking contests.[10][11][12]. First of all you need two people When the beam has cured, trim off any excess wood to make planar surfaces, and sand off the excess resin. These are the horizontal beams that are used as the track. 24. This is the pin. ratio of counter weight to projectile about 90 to 1 weight. Reply The idea of inserting a trebuchet into the dynamics 3. Then cut the axle about 3 inches shorter than the width. The first through fifth sketchup picture will show this. User Projects. 2. 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. NEVER, NEVER LEAN OVER THE ARM!!! The trigger pins keep the weight from falling. 11. Just make sure there is a washer on any side of a bolt that will be touching wood. These are really simple. Tie the longer end of the rope through the hole in the end of the arm. Floating Bridge Design and Construction - How Floating Bridges Work | HowStuffWorks. 5 years ago. They must be perfectly straight and lined up. WebStep 2: Prepare the Arm. Line up the pieces of plywood and drill holes through everything for the carriage bolts. Fill the bucket with rocks or heavy pieces of metal. This way, the screws take force from top to bottom, not sideways. This will be the top. Yes I want a small one for the classroom and large one for the field. A regular trebuchet is a better realistic war machine. Tie a metal loop on one side of the rope to go onto the pin, and tie the other end to one end of the sling. The arm will not swing up. The cutouts go around the main track supports. Well, they didn't becasue I did not have a drill press. 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. Yeah, this happened to me. Cut a piece of steel pipe for an insert and place it at the center of each form, then pour the concrete. I would probably actually be dead. The trigger will be added later. Lower it below the base, just rest it on the floor. Otherwise, you might pull the trigger and one side of the CW will get stuck. (0.635 cm) diameter, 5.5 in. (0.635 cm) bolts, matching thread (Note: rope angle of 45 is different than arm angle of 90-105) Nylon rope held fine, but it stretched every time we fired, making fine-tuning tough. Floating Arm Trebuchet Page 3 of 3 First 1 2 3. We are building one now, it has been lots of fun for the family. although I'm still not quite sure how that happened. This film is made to demonstrate some easy steps to go through when making a FAT (Floating arm trebuchet). (1.5875 cm.) 2 hand weights, 10 lbs (4.54 kilos)* SECOND PROBLEM These keep the distance between the two tracks from narrowing or widening. Do some experiments, that part is the most fun. 3 years ago. That should be about 2 inches from the end of the track. Although the trebuchet will work so small, it might be better to increase the arm ration. Thats a bit longer than 7 feet because i rounded 7 4.5 up, it was really 1.55555555 2 segments of 1 ft., 0.5 in. 11 years ago Mark the height that you want the diagonal support to rise to. After looking at the dozens of picture I took, It should be pretty easy to figure out how to put everything together. thank you, Reply by 2 in (0.381 X 0.0508 m) Their defining feature is free movement of an axle on the throwing arm,[2] and a linear drop channel for the counterweight. Then drive 2 screws through the board with the actual channel on either side of the gap, diagonal from each other so that you can fit two into the narrow width of the wood on either side of the gap. This will take more weight off of the long arm, which should be as light as possible. And send me some pictures :D. I tried to reply but it wouldnt let me so this is my other option. If it's too narrow at the top then the smooshing will happen as they fall closer to the bottom. On the end of the arm, there will also be a nail, or some sort of strong metal pin. Make sure the axle bolt is short enough to clear the frame easily. 15 in. 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