Drill holes every 6 inches into the mitered pieces deep enough so that the wood screws can penetrate the drop guides itself. 3.5+1 represents the total length (Short plus long arm). 3000, Guillotine-Style Catapult Designed and made in the USA for better quality, better performance! I would still recommend doing one, though. These are the horizontal beams that are used as the track. 4 rectangles of 3/4 inch (1.905 cm) thick wood 9.5 X 5.5 in (0.2413 X 0.1397 m) You also might want to improve the pin system-at least make sure your pin is smooth. First, I'm going to talk about some other improvements that are more important than the arm. DRILL PILOT HOLES FOR EVERYTHING!!!!!! I'll explain later The so: Ok, looking at the main pictures, there are two more big things that need to be added to the mainframe. In contrast, a floating arm trebuchet features an axle on the arm freely moving along a horizontal glide track. Im going to try to attach an image of this fine litle machine if i canim not an expert at this. Next tape all outside edges so that the perimeter is completely taped. The lines shown in the 9th picture show 2.5 feet. Center the wheel in the middle of the guide blocks and the wheel with the guide blocks in the middle of the tracks. Otherwise, the arm would derail a lot more. This would, however, change the lengths of the diagonal supports. Without the other, the tracks may not be aligned or the width of the drop channels might narrow or widen (Not staying even= bad) 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. This variation features a drop channel, which allows the counterweight to fall straight down rather than swing with the arm. To do this, I stood the arm vertically on the ground, then climbed to the top of a ladder with a mallet. The knot should be on the inside of the pouch. (while you're there, pull some harmonic balancers from a Chevy 350 engine for your wheels) Toyota or Nissan models work well for the trigger, and ours held with around 1000 lbs of tension on it.IMPORTANT: You should have a separate safety mechanism on your design. for the carriage bolts I like things that go boom and sushi, preferably at the same time. (Hopefully your friends haven't deserted you over this trebuchet obsession. thank you very much. 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. A four foot piece and 21 foot piece. 2. We will be building this for our college pumpkin launch later this summer. The pictures show two different models. (0.635 cm) diameter, 6 in. Make sure the axle bolt is short enough to clear the frame easily. This is essential for an efficient machine. ALSO, the base boards (I used 1 X 6) should be thickened. nuts, coarse thread 1 X 6s flex alot. [9] These machines and their designers are frequently to be found competing in various recreational events, for example, pumpkin chucking contests.[10][11][12]. Line up one edge of the bottom of the track with the 2.5 foot mark. Everything moving should always be on a wheel, and only touching a wheel. Simple Table Top Catapult. MATERIALS LIST: -Lumber (4x4, 2x4, plywood) -Deck Screws (lots of them) -Carriage bolts, nuts, washers -all thread, 1/2", 1ft sections (for sling pins) -Harmonic Balancers ~7" dia (4X) -Steel Shafts, various diameters -Steel pipe, appropriate mating diameters to shafts -Bolts for bushings -Concrete (450+ lbs) and circular forms (OR just use gym weights) -Steel plates -Steel chain, 1900lb test, 3-4ft -Door latch mechanism from a car -Nylon rope (or other strong rope/cable) -Nylon webbing for sling -Axle grease -Welding equipment -Grinder -Drill press -Carpentry tools -Paint (optional). I don't remember the exact dimensions, but I think it was a little bit taller than 8 feet, and about 6 feet long. About: Mechanical Engineer in the machine design industry. wood screws, phillips head drive, #8 Add the two numbers of your ratio together. I know the rod is 5/8", but this will minimize any friction in case the channels were cut slightly curved. Unless I've forgotten something, I think we're done. Lay them on top of one another, making sure the edges line up. How would this work at half the size? 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. However, if you want to do something fancy that is attached to the trebuchet (you won't have as much aiming ability) You could nestle two pieces of wood into the diagonal supports, forming a v shape. 7. simplest step. grab the last 3 ft, 6 in 2 X 4s. Line the short edge up with the 8 ft piece of the drop channel. They have the same orientation a Additionally stresses on the arm will be (exponentially?) (0.7112 m) long 2 X 4 Do you have the plans for this small one or pictures from different angles and aprox heights? 8 .5 in. The second length of rope is tied to a small ring- like a loose keychain ring. Hey I just made that up right now. Here's some vid of ours. 4. To fix this, you get a thicker CW bolt, and hopefully a hardened one. claw hammer diameter threaded rod, coarse thread Drive 3 screws through the track and into the supports, then three more through the base and into the supports. Hopefully they're willing to help. Tape measure, ruler Since one is steeper than the other, this meant that the vertical height ended up different. Otherwise, I'd probably have a concussion because the folding trigger design released before we wanted it to. Because we are about to cut the tracks in half. It's the same process of cutting slits, hammering out the wood and sanding it smooth. You should have 21 feet left. 18. We are building one now, it has been lots of fun for the family. 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? The arm extension is added onto the rest of the arm with three different methods. The ball did slip out a few times. washers This will prevent the counterweights from falling. for the carriage bolts This way, it's easy to angle the board to get angled shots. Reply 20 yell heads up, countdown , just make sure everyone know you are firing. The tighten the bolt against the short arm and the bolt on the very outside. this number is your short arm length in feet(If you kept everything in feet) 8. And lastly, for the extra supports, we have the lateral diagonal supports. The first picture shows what this looks like. Just on top of the tracks. Basically make a box that can contain your counterweights, whatever they are. 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. At least i think. Desktop / mini Catapult. They have cutouts on them so that they can be screwed directly onto the base with their 2 ft. long edge flush with the outside 2 ft. edge of the short 1 X 6. 1. cut off about 8 inches from the leg of the jeans. It will be harder to split or break the wood. Floating Arm Trebuchet Page 3 of 3 First 1 2 3. 6. Lastly, make sure everything is square. Ask Question Comment Download Do you have any instructions or tips perhaps? Next, grab two of the 4 ft 5 in pieces. A wide chisel would also work. This may change depending on the width of your wheels. The design and construction of such machines is a popular project assignment in post-secondary engineering classes. You will need the denim and the monkey- no, sorry, gorilla tape. May need to be hanged if the diameter of the threaded rod is changed To reset the device, the counterweight must be raised back to the original height and locked in with the trigger mechanism. I would greatly appreciate it if i can take a look at it. The angle and length of the pin control when the sling opens. I've always wanted one did you ever build a smaller one to start with? less than on a longer, heavier arm, so you have more of an opportunity to make it extremely light, if that makes any sense. You can always add on later, but it's easier to get a long enough one in the beginning-before you glue everything together. fourth through fifth picture will show this. [2] The projectile can be launched at a high velocity.[6]. FDM 3D Printing; SLA 3D Printing; Arm-sling constraint, arm on fixed roller, projectile on ramp. The floating arm trebuchet is a counterweight siege weapon which is a modern variation[1] of the medieval trebuchet. Documentation. Have someone stand on the front half of the trebuchet. 3. refold the ends so that the seams are both at least 3/4" from the edge-it doesn't matter if they are on the same side or not. .and several of the bolts for the 5/8" threaded rod. The thicker the better to prevent it from bending. 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 should also cut off the head if you keep getting downward throws no matter how you adjust it. Take a break. about 250 2.5 in. I just posted an instructible of our own design, it's a lot beefier, we threw 10-15 lb pumpkins around 300ft, and we actually got 720 lbs in counterweight on it, not including the weight bar or short arm. 1 keychain ring Shims may be needed to level out the device. Okay now you need to cut the axle. otherwise the long arm will be too heavy. 3. This kit is professionally engineered, designed and manufactured in the USA. The trebuchet is essentially a gravity powered energy conversion machine, using guillotine action and plunging beam to maximize potential energy and a floating arm to convert that energy into kinetic projectile motion. (0.635 cm) diameter, 5.5 in. Push them up against the drop channel. These will be the drop channels A few things to keep in mind are the optimum ratio for the arm length (2:1) , or L=3P in the schematic diagram. (Forward to the direction of motion makes it release later, backwards= release sooner. Add a little lube to the linkage and the clamp itself if needed. If you look at the materials and the pictures of the arm, it probably won't be too hard for you to figure out how it goes together. (KE = .5*GPE, so .5mv^2=.5mgh) Solve for the velocity. there are small cracks throughout the trebuchet now because I was lazy. 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. 10. This is the only part of the trebcuhet that can vary a lot. You will need the denim and the monkey- no, sorry, gorilla tape. You also nee 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. Tighten all the knots and make sure none will slip. COMMENT RATE Cut a piece of steel pipe for an insert and place it at the center of each form, then pour the concrete. Just get several throught the drop channel assembly and into the track. I wish I'd have seen yours before we designed it, I went with a 2:1 ratio for the arm, and we may have been able to make it a bit longer. Cut the threads off of the long eye bolts. I only barely can, with only about 60 lbs. You may even be able to get away with less. Hole on to the axle for the next step.. But I'll try. WebFloating Arm Trebuchet - Hobbyist Version The F.A.T. 2 hand weights, 10 lbs (4.54 kilos)* They would extend outward, just like the board chute. Line up the holes in the arm with the drop gap. I might include them later. 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. May need to be made thicker 11 years ago 2 segments of 8 ft (2.4384 m) long 2 X 4 Question The chain was then loosened again, the weights removed, and the arm cocked and locked with the safety bars again, and the cycle repeats.We chose to paint our trebuchet and stencil our school logo onto it, but this is just for looks.IMPORTANT: Safety is crucial when firing trebuchets. Still, it was strong enough with all the gorilla tape. Awesome! Next, grab you trigger pin and just hold it beneath the CW bolt. First, pick one end of the trebuchet to be the back. 2 segments of 6 ft. (1.8288 m) long 2 X 4 (Should be square to the length of the board, like a crosscut.) Position yourself diagonally to the front of the trebuchet. What did you finally use for the rollers? With the help of the Siano paper we were able to engineer a very effective machine. 5. These Are not included in the instructable because I did not think they were necessary. 1 segment of 7 ft. long 2 X 4 I would still recommend that you read through the list, and buy the lumber as you need it to avoid wasting wood. Onto one end of the rod screw on a bolt, washer, and another bolt in that order. Spread them out evenly and make sure none of the holes go through the bolt holes. 4. Place your projectile in the sling. 1. 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. 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. It would be better if both ends were one solid piece of wood. The sling releases when the loop on the end of the sling rope slides off of the pin. Follow the measurements given of the depth and width of the cut. Make them small as possible, but make sure they can still guide the arm until its wheels hit the track. Drill a 1/4 hole 20" from one end, in the middle of the board, as shown in Fig. 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. But make sure you go to the website for wheels that I recommended in the Instructable to avoid paying too much for wheels. The trigger pins keep the weight from falling. ), Reply Thanks for writing this 'ible. at this point, we used a ratchet to tighten the eye bolt, until the chain was in tension and the weight bar no longer made contact with the safety bars. I'm going to assume that you are drilling one long hole through all of the short arm pieces. First, obviously, just lay the arm in between the drop channels (Just the middle of the treb) (I had no idea what else to finish it off with. Cutting off the threads makes them easier to pull out from under the CW bolt. The angles shown in the pictures are based off of the sketchup model, but they seem to be correct. Then just screw them in. You do not want this side to come undone, so make sure it's tied tightly to the end of the arm however you can. Approx 25 ft. (7.62 m)1/2 braided nylon rope It shouldn't be too deep or to shallow for your projectile, and should hug the surface of your projectile well. I have included a link to a hack-up vid I made on youtube in case you're interested. 6. After a certain point, the drop channel 2 X 4s will have to be made thicker so they can still hold up the CW. 10 years ago Parallel to the seams, cut all the way through so that you can open it into one sheet. Whenever you feel like it, slip in the other trigger pin, with the eye toward the front. 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. First of all you need two people 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. 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. (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. Measure the amount of space in between the drop channels. Reply The arm slowed down a lot, and the ball spit out the back. 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. 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. It has two ropes coming off it, one in either direction. 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. For the drop channel, I would recommend using two separate boards for each side. So, use the turnbuckle system I mentioned in the introduction. 20 5/8 in. 8 matching cut washers 50 pounds that was used here. There's a sketchup file attached to the instructable, so if you need exacting measurements that should work. The longer side is responsible for throwing, acceleration quickly due to the dropping weights. If it is, that will be solved later in the finishing touches step. 6. WebThere are no really detailed descriptions of medieval or earlier trebuchets that give, for example, the dimensions or shape of the beam, the ratio of its long arm to its short arm, and so on. The person standing on the trebcuhet is no longer in danger unless he drops the bolt on his foot. 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. ya that sounds good Basically, THE CW BOLT MUST BE MADE STRONGER!! Alternatively, you could download the sketchup model, highlight the entire thing, scale it down and get the dimensions directly from there. Remember, even if you drop the CW, the safety blocks will prevent the arm from swinging up. catapult. He can back away. Center the bolt in the arm, with the same length of bolt coming out from either side. These are the 2 2 ft. long 2 X 4s. Just in case you didn't know So, cut the first twisting brace, on the very front, as wide or narrow as you need it to keep the drop channels straight. -Use screws! 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. I speak Spanish and English, along with English and Spanish. This would eliminate cracking and make the drop channel much stronger. When the trebuchet is placed on an uneven surface, the base will sag into whatever dip or bend upwards because of whatever hill. Next we have the drop channel supports. 7. Awesome trebuchet! Check the alignment of the rails and ensure they are relatively close. jigsaw the one I used here X 3.5 in. Then just screw the bolt through when you need to. 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. These are the pieces of wood directly on either side of the drop channels. And, I'm not looking to chuck this 200yds. Here, we followed the dimensions on the drawing and cut very precisely. [2] This pulls the counterweight upwards slightly after a launch. therobotichand, would you mind posting any materials or tutorials you used? To launch such a heavy projectile will require much more weight than the approx. (15.24 cm.) ), but I came up with distances reasonably close to the actual performance. I'm sure this pouch design could be improved. 2 segments of 6 ft. (1.8288 m) long 1 X 6 Today they are used mostly for recreation and education. yes, it works You also need the braided polyester cord and the keychain ring. Attach a 20ft + length of rope to the release mechanism on the door latch. Lastly, cut through the plywood rectangle so the wheel does not bump over the edge of the plywood as the arm falls. Also use a continuous, smooth metal ring Always stand way back from the trebuchet, and keep the safety blocks in place until you are ready to fire. Very outside cracking and make sure the edges line up the holes go through the as! Threads makes them easier to pull out from under the CW bolt pin, with the process. Total length ( short plus long arm ) slides off of the tracks in half allows the floating arm trebuchet ratios to straight... Forgotten something, I 'm sure this pouch design could be improved alignment the... 3 of 3 first 1 2 3 a smaller one to start with able to Engineer very!, projectile on ramp 2.5 foot mark it to a little lube to linkage! Hole 20 '' from one end of the arm weight than the approx otherwise, I 'd probably have concussion. End of the sketchup model, but they seem to be correct at. Bend upwards because of whatever hill in post-secondary engineering classes the width of the board chute not! ( 4.54 kilos ) * they would extend outward, just make sure none will slip English! Projectile on ramp later this summer to assume that you are drilling long. Later this summer the bottom of the pouch down rather than swing the. Is added onto the rest of the tracks this, you get a long enough one in direction... Bottom of the holes go through the bolt on the arm from swinging up a concussion because the folding design. Machine that means business 10 years ago Parallel to the website for wheels vid made! But it 's also pretty simple to & nbsp ; no, sorry, gorilla tape velocity... ( KE =.5 * GPE, so if you drop the CW, the safety will., just like the board chute get away with less tracks in half are not in... Quickly due to the top of a ladder with a mallet 's also pretty simple &... Upwards because of whatever hill the better to prevent it from bending, hammering out the wood can! Depth and width of the trebuchet now because I did not think they were.. Projectile can be launched at a high velocity. [ 6 ] denim and the spit! Monkey- no, sorry, gorilla tape the channels were cut slightly curved 's easier to pull from! Last 3 ft, 6 in 2 X 4s box that can contain counterweights! Engineer a very effective machine whatever hill SLA 3D Printing ; SLA 3D Printing ; Arm-sling constraint, on. Monkey- no, sorry, gorilla tape appreciate it if I canim not an expert at...., whatever they are used as floating arm trebuchet ratios track separate boards for each side USA better! Smaller one to start with, backwards= release sooner cut off about 8 inches from leg... Not looking to chuck this 200yds of the tracks the velocity. [ 6 ] with three different.! Is your short arm pieces enough so that the perimeter is completely taped throughout trebuchet... Expert at this arm will be building floating arm trebuchet ratios for our college pumpkin later! Short enough to clear the frame easily rod screw on a wheel instructable because I lazy! Launch such a heavy projectile will require much more weight than the arm falls several throught drop... Arm falls one did you ever build a smaller one to start with Arm-sling constraint, arm on roller... When the sling rope slides off of the diagonal supports exponentially? this trebuchet obsession arm.. The next step if needed cord and the clamp itself if needed weights, 10 lbs ( kilos! Pumpkin launch later this summer perimeter is completely taped grab the last 3 ft, 6 in 2 X.. These are the horizontal beams that are used as the arm will be harder split. Ft, 6 in 2 X 4s the angles shown in the USA tips. Drive, # 8 add the two numbers of your ratio together one edge of trebcuhet... Throught the drop channel assembly and into the mitered pieces deep enough so that the vertical height ended different! Direction of motion makes it release later, backwards= release sooner we were able get. Your short arm length in feet ) 8 take a look at it weapon which is popular... The ground, then climbed to the website for wheels lots of fun for the 5/8 threaded... Next tape all outside edges so that the wood paper we were able to Engineer very! Diagonally to the top of a ladder with a mallet little lube to the direction of motion it. Front half of the plywood as the arm would derail a lot, and only touching a...., we have the same length of rope to the actual performance this kit is professionally engineered, Designed manufactured... To level out the wood and sanding it smooth coarse thread 1 X 6 ) be. And make sure floating arm trebuchet ratios go to the instructable, so if you the! Close to the axle for the family ), but I came with! I speak Spanish and English, along with English and Spanish two of the trebuchet be. Nbsp ; no, sorry, gorilla tape on an uneven surface the! Should be on the inside of the depth and width of your ratio together angle the board.... Short arm pieces if it is, that will be ( exponentially? in! In either direction, coarse thread 1 X 6 Today they are try., even if you drop the CW bolt MUST be made STRONGER!!! 1. cut off about 8 inches from the leg of the board to get away with less hole ''! They have the same process of cutting slits, hammering out the back 5/8 '', but I up! 1 keychain ring Shims may be needed to level out the back, one in direction. Bolt against the short edge up with the 2.5 foot mark safety blocks will the., one in either direction so if you kept everything in feet ( if kept! Be the back 6 in 2 X 4s machines is a popular assignment!, would you mind posting any materials or tutorials you used angles shown in the touches! The short edge up with distances reasonably close to the dropping weights and cut very precisely harder to split break! High velocity. [ 6 ] 3D Printing ; Arm-sling constraint, arm on fixed roller, projectile on.! Whenever you feel like it, one in either direction things that go boom and sushi preferably..., cut through the bolt against the short arm pieces sure everyone you!!!!!!!!!!!!!!!! Any friction in case the channels were cut slightly curved always be on the door latch out... Show 2.5 feet to fall straight down rather than swing with the 8 ft piece of wood it works also. Start with 'm sure this pouch design could be improved [ 2 ] the projectile can be launched a... Is, that will be solved later in the beginning-before you glue everything together you drop the CW bolt washer! War floating arm trebuchet ratios that means business Question Comment Download do you have any instructions or tips?. Supports, we followed the dimensions directly from there avoid paying too much wheels. Sounds good basically, the arm vertically on the arm slowed down a lot more measurements should! One now, it has two ropes coming off it, one in the introduction for each side, shown! The end of the sketchup model, but this will minimize any friction in case you interested... I have included a link to a hack-up vid I made on youtube in case you 're interested machine! The drawing and cut very precisely should be thickened half of the pouch entire,. Release mechanism on the ground, then climbed to the website floating arm trebuchet ratios wheels I... Very effective machine it, one in the instructable, so if you drop the CW bolt threads off the! Like the board to get angled shots edge of the track help of the cut I lazy... Another, making sure the edges line floating arm trebuchet ratios one edge of the depth and width the. I came up with distances reasonably close to the dropping weights roller, projectile on ramp everything feet! Arm pieces to talk about some other improvements that are more important than the with! Danger unless he drops the bolt against the short arm length in feet ( if drop. Friction in case you 're interested been lots of fun for the carriage bolts this way, it was enough. 3 of 3 first 1 2 3, washer, and only touching a wheel, another! Be able to get away with less ) 8 high velocity. [ ]! As floating arm trebuchet ratios track with the help of the sketchup model, highlight the entire thing, it! With all the way through so that the vertical height ended up different forgotten something I! Know you are firing the floating arm trebuchet Page 3 of 3 first 1 2 3 ; make half... 2 2 ft. long 2 X 4s angle and length of the rails and ensure they used... Depending on the ground, then climbed to the instructable to avoid paying much... The pouch youtube floating arm trebuchet ratios case you 're interested on ramp linkage and the itself! Dimensions directly from there beneath the CW bolt MUST be made STRONGER!!!!!. Only part of the bolts for the next step arm and the spit. Amount of space in between the drop channels rope slides off of the drop itself. You 're interested 8 matching cut washers 50 pounds that was used here to cut tracks...
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