floating arm trebuchet efficiency

The dowel should spin freely, but the washers should remain in place. Summary: I want to make a floating arm trebuchet because I think it would look cool. My FAKA has misfired once, and it lead to the wheels smashing into the front stop and derailing the arm. [40] In 652, the Arabs used trebuchets at the siege of Dongola in the Sudan. [6] They may have been used in Germany from around 1205. I highly recommend this design. Several arm derailments have been caused by this. In 2021, an individual named David Eade designed a trebuchet reaching supersonic speed. Account & Lists Returns & Orders. they like to compete. One of the most simplest designs but what it has in simplicity it lacks in efficiency. ), Barrett, The Honors College Thesis/Creative Project Collection, Mechanical and Aerospace Engineering Program, Sharing Materials: ASU Digital Repository Guide, Trebuchet Mechanics: Modeling and Optimization of the Trebuchet. https://jaanmarss.planet.ee/juhendid/Mehaanilised_kaugrelvad_keskajal/andmebaas/Russell%20Miners/htt01.html, "Medieval Warfare during the Cathar Crusades", "War in the South: A First Look at Siege Warfare in the Albigensian Crusade, 12091218", "By hook or by crook: Siege warfare in the fourteenth century", "armedieval - le trebuchet et les machines civiles et militaires mdivales", "World Championship Punkin Chunkin Current World Records", "Season 8 Filming: Watch a trebuchet test at Titanic Studios", Experts reveal the science behind 'the world's biggest trebuchet' on You Have Been Warned, Car is launched from trebuchet at Shropshire fundraiser, The Grand Tour: This Is What Happened To The Carnage A Trois Trebuchet, The Grand Tour's "Carnage a Trois" Episode Falls Largely Flat, YouTuber Colin Furze creates trebuchet in Stamford, THIS MASSIVE HOMEMADE TREBUCHET CAN LAUNCH WASHING MACHINES, "World's Simplest and Newest Trebuchet (Walking Arm Trebuchet): 17 Steps (with Pictures)", "Vermont Pumpkin Chuckin' Festival: Results of the 10th annual Vermont Pumpkin Chuckin Festival", "Vermont Pumpkin Chuckin' Festival: The Final Results and Report for the 8th Annual Vermont Pumpkin Chuckin' Festival on Sept. 25th, 2016", "Ukrainian Protesters Built A Giant Catapult To Fight The Riot Police", "English Artillery 1189-1307: The Implications of Terminology", "Experimental Reconstruction of the Medieval Trebuchet", "By Hook or by Crook: Siege Warfare in the Fourteenth Century", "The Traction Trebuchet: A Reconstruction of an Early Medieval Siege Engine", "Trebuchet - A Gravity-Operated Siege Engine: Study in Experimental Archaeology", Secrets of Lost Empires: Medieval Siege (building of and history of trebuchets), https://en.wikipedia.org/w/index.php?title=Trebuchet&oldid=1142306451, Articles with dead external links from June 2022, Articles with permanently dead external links, All articles with bare URLs for citations, Articles with bare URLs for citations from August 2022, Wikipedia pending changes protected pages, Short description is different from Wikidata, Articles with unsourced statements from January 2022, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 1 March 2023, at 17:51. Summary: I want to make a floating arm trebuchet because I think it would look cool. We're doing our part, now you need to do yours. What better way to develop an interest in physics than to play New machines have been constructed and old ones restored by living history enthusiasts, for historical re-enactments, and use in other historical celebrations. [106][107], Counterweight trebuchets at the siege of Nicaea (1097), c. 1270[108], Counterweight trebuchet at the siege of Nicaea (1097), 1337[108], Mahmud of Ghazni attacks the rebel fortress (Arg) of Zaranj in Sijistan (Nimruz province) in 1003 AD, from the Jami' al-tawarikh, c. 1306-18[1][2], 15th-century depiction of a counterweight trebuchet, 16th-century depiction of a counterweight trebuchet, Possibly a counterweight trebuchet (however text says cannon) from the Chinese encyclopedia Gujin Tushu Jicheng, 1726, Early 18th-century depiction of a Chinese ship armed with three counterweight trebuchets[109], With the introduction of gunpowder, the trebuchet began to lose its place as the siege engine of choice to the cannon. This variation features a drop channel, which allows the counterweight to fall straight down rather than swing with the arm. Writing in 1280, Giles of Rome claimed that hinged counterweight trebuchets had a greater range than fixed counterweight types. Scientific American: 6671. [78] Despite the lack of clearly definable terms in the late 12th and early 13th centuries, it is likely that both Muslims and Europeans already had working knowledge of the counterweight trebuchet beforehand. The string length will also affect how far your projectile will launch. VirtualTrebuchet is a web based trebuchet simulator that will allow you to quickly evaluate different trebuchet configurations. [24][25][26], The first recorded use of traction trebuchets was in ancient China. By the 1230s the counterweight trebuchet was a common item in siege warfare. [62] Sometimes counterweight trebuchets are separated into two or three different categories based on how their counterweights are attached. Step 6: Join trebuchet sides. the Parthenon. Although the murlin trebuchet has an efficiency of 90% it is a lot more difficult to construct and would take to . "[91] In 1220, Al-Mu'azzam Isa laid siege to Atlit with a trabuculus, three petrariae, and four mangonelli but could not penetrate past the outer wall, which was soft but thick. Give the trigger a swift tug to release the pins! [39], The traction trebuchet was most efficient as an anti-personnel weapon, used in a supportive position alongside archers and slingers. Another trebuchet I designed and built for a school project. Floating Arm Trebuchet In this high-efficiency design, the counterweight is constrained by a track to fall straight down. Read the documentation or contact us. A fixed counterweight is an intrinsic part of the swinging arm and its trajectory is circular. This is a more efficient way to transfer potential energy into kinetic energy at a small scale. The goal is to use the weight of the counterweight (rather than friction) to hold the pins in place. Since we built this trebuchet in two short days, it wasn't very strong. The origin of the word "trebuchet" is uncertain. The FAKA is a trebuchet design invented in late 2006 by Craig Macomber. If you have a hundred of those machines, then when you are ready to march, each wooden pole can be carried by only four men. They work great over a huge range of mass ratios. [11], Traction trebuchet and counterweight trebuchet are modern terms (retronyms), not used by contemporary users of the weapons. The Wheel/Spoke Trebuchet - a variation on the HCW design that allows for a vertical drop. the Aqueducts and Roads of the Romans. It was determined that the optimal arm length ratio was approximately 1:2, where the short . For a better experience, please enable JavaScript in your browser before proceeding. [66] However the source for this was written in the 1180s to 1190s and Niketas may have been placing the engine of his own time anachronistically into the past. It has derailed several other times, but so far no major damage has occurred. (14 pages!) Track Gap in many designs; Hard to build . This is a more efficient way to transfer potential energy into kinetic energy at a small scale. The floating-arm type is. Model Do some target practice with your kids in the :p. I've never seen this "floating arm" style of trebuchet before. This newest version of our 21st century trebuchet is manufactured from top-quality engineered hardwood plywood. The date the item was original created (prior to any relationship with the ASU Digital Repositories. For this year, a good distance will probably be around 30. The rollers in the arm can be positioned into different holes, thus altering the position of the fulcrum. It rang hollow. Basic physics will tell you your ideal launch angle in 45 degree in the absence of air resistance. Accordingly, it was only profitable to employ counterweight trebuchets if they were capable of harnessing noticeably more energy, allowing them to throw significantly larger stones or similarly sized stones greater distances. [92] As late as the Siege of Acre (1291), where the Mamluk Sultanate fielded 72 or 92 trebuchets, including 14 or 15 counterweight trebuchets and the remaining traction types, they were never able to fulfill a breaching role. [8] Paul E. Chevedden suggests that manjaniq maghribi was used to describe hinged counterweight engines in contrast to previous fixed or hanging counterweight trebuchets. This machine lets you get your counterweight higher than a traditional trebuchet but keeps the pivot point low enough to keep with the rules of our competition. Below is. [140] Another recent development is the "flywheel trebuchet,"[142] in which a flywheel is spun into rapid rotation to build up momentum before release. Usually gravity or springs. To include the sling, a much more constraint-intensive (5DOF) approach is required. Use the 5" (12.5 cm) pieces of paint stirrer and the four 6" (15 cm) square dowel pieces to form the glide rails. Windows 7 Ultimate x64, Mint 9 New 15 Jan 2010 #1. [147], Modern recreation of a Mongol-era traction trebuchet, Inner Mongolia Museum, 19th century French drawing of a medieval counterweight trebuchet, A modern improvised trebuchet erected by rioters in Hrushevskoho Street, Kiev, Ukraine, 2014, Counterweight trebuchet at Chteau des Baux, France, A scale model of a trebuchet, based on the design of the "Warwolf". Some of these more powerful engines may have just been traction trebuchets, as one was described being pulled by ten thousand. Click here to Magnet Download the torrent. Skilled in new technology research, proof-of-concept development, innovation planning and long-term strategy to unify business interests with technological advancements. "[27] However according to Joseph Needham, the large tank in the middle was the counterweight, while the bulb at the end of the arm was for adjusting between fixed and swinging counterweights. Carried westward by the Avars, the technology was adopted by the Byzantines in the late 6th century AD and by their neighbors in the following centuries. Adjusting the sling's release point is the primary means of fine-tuning the range, as the rest of the trebuchet's actions are difficult to adjust after construction. The floating arm trebuchet uses rails to constrain the counterweight vertically and to allow the arm pivot to move horizontally. "It'sThe Hurl itself that matters! Any questions? Stand to the side of the trebuchet to avoid being struck by a wayward projectile. Of this, the Hongwu Emperor stated in 1388: "The old type of trebuchet was really more convenient. [74][75][76] Though soon after, clear evidence of counterweight machines appeared. [85], The design of the Muslim trebuchets came originally from the Muslim countries, and they were more powerful than ordinary trebuchets. The form and density of the projectile have a big impact on how well the trebuchet performs. The trebuchet is a type of catapult that was popular for use as a siege engine before gunpowder became a thing. "[90], In spite of the evidence regarding increasingly powerful counterweight trebuchets during the 13th century, "it remains an important consideration that not one of these appears to have effected a breach that directly led to the fall of a stronghold. He demonstrated the device on YouTube[143] and published his simulation software on GitHub. After the projectile is released, the arm continues to rotate, allowed to smoothly slow down on its own accord and come to rest at the end of the rotation. Trabucha is found a decade later with predariae at the siege of Castelnuovo Bocca d'Adda in an account by Iohannes Codagnellus. ASU Library welcomes members of the Akimel Oodham and Pee Posh, and all Native nations to the Library. . Chevedden, Paul E.; et al. View and manage file attachments for this page. (Best Sex Pills Over The Counter) aloe vera to make penis bigger Faculdade Santa Helena what supplements make your penis bigger Best Male Enhancement. Watch headings for an "edit" link when available. Super awesome! [50] At the siege of Haizhou in 1161, a traction trebuchet was reported to have had a range of 200 paces (over 400 meters). 2023 Physics Forums, All Rights Reserved, Trying to Figure out Tension force angle on Arm, Evaluating minimum and maximum values with calculations, Statics: Hydraulic jack lifting a telescopic extension arm ("Cherry Picker"), Density versus Pressure -- Balancing the bouyancy of a floating capsule, Hollow and solid spheres floating in liquid, Resultant pedal force (FRESULTANT) Force tangential to the crank arm, Cylinder in a slotted arm moved by a forked rod (particle dynamics, kinetics). The washers and nuts will be assembled onto the bolt in the order shown. During an assault on Muntcada by King James I a trebuchet was used to target a tower, destroying the structure and causing the consequential deaths of civilians and livestock. A floating arm Trebuchet allows a straight drop of the counterweight which results in more efficiency. How wide were your paint stirrers? [104] They could also be equipped with their own wheels, as shown in two 17th- and 18th-century Chinese illustrations, which are also the only Chinese depictions of counterweight trebuchets on land. Step 3: Drill holes for pivot arm. Notify administrators if there is objectionable content in this page. How do you make a perfect trebuchet? The upper arm stop is also a problem because after the throw the hanger can slam into it quite hard. It works by dropping a counterweight in the middle which is attached to the arm. [27][82] The earliest definite mention of the counterweight trebuchet in China was in 1268, when the Mongols laid siege to Fancheng and Xiangyang. The rotation speed of the throwing beam increases smoothly, starting slow but building up quickly. Cut off any excess dowel to prevent it from getting caught on the drop channel beams. [17] The trebuchet had further modifications to allow an increase to its range, by creating a slot for the sling and projectile to sit underneath the trebuchet, enabling the sling to be lengthened and thus extending the range, an alteration in the trajectory, or the release point to be changed. The trebuchet must fit within an 8 ft cube, except for the throwing arm, which can be any length. View wiki source for this page without editing. "[79][80], Counterweight trebuchets do not appear with certainty in Chinese historical records until about 1268. Michael the Syrian noted that at the siege of Balis in 823 it was the defenders that suffered from bombardment rather than the fortifications. Operation Trebuchet: Efficiency of the Floating Arm Information: This trebuchet project was our Engineering Physics project at New Horizons Governor's School for Science and Technology in Hampton, Virginia for the 2010-2011 school year with Dr. Truong Le. With. Drill four 1/4" (6 mm) holes into a square dowel. The floating arm trebuchet uses a counterweight the vertically falls down a shaft created by two pieces of wood. The entire argument for the existence of hybrid trebuchets rests on accounts of increasingly more effective siege weapons. The design of a trebuchet allows it to launch projectiles of greater weights and further distances than that of a traditional catapult. The boogies, or trucks, which ride the tracks, need to prevent the axle from twisting relative to the frame, If one side gets ahead of the other, it will likely jam, but the counterweight or the arm might also strike the frame. In the simplest setup, there is nothing designed to absorb energy, and it can not swing back and forth like most trebuchets until it stops. The optimized sling length was 4.45 feet. Learn a new skill. Drill two sets of holes using the 1/8" (3 mm) bit for the trigger pins. View and manage file attachments for this page. Using the cutting guide shown, cut the two-by-threes, two-by-two, and one-by-three to length. when [the artillerists] wanted to hurl them to a great range, they added weight [to the counterpoise] and set it further back [on the arm] when they needed only a shorter distance, they set it forward, nearer [the fulcrum]. Something does not work as expected? I'm a writer, maker, and educator who's on a mission to better the world through hands-on engineeri, seven 12" (30.5 cm) square dowels, 1/2" (1.3 cm) wide, Strap-On Cleats for Ice and Snow Traction, Hollow Wood Surfboard - Plywood and Cedar, Cut two 12" (30.5 cm) paint stirrer into four 6" (15 cm) pieces, Split two of the 6" (15 cm) pieces down the middle, Cut the bottom of the split pieces at approximately a 45 angle, Cut 2 paint stirrers into four 5" (12.5 cm) pieces, leaving two 2" (5 cm) pieces. In recent years several trebuchets has been created capable of throwing cars. [146], In 2014, during the Hrushevskoho street riots in Ukraine, rioters used an improvised trebuchet to throw bricks and Molotov cocktails at the Berkut. [88] Marshall maintains that "the methods of attack and defence remained largely the same through the thirteenth century as they had been during the twelfth. . are complete with diagrams, photos, tuning tips, equations for calculating the machine's efficiency and more! [67] At the siege of Nicaea in 1097 the Byzantine emperor Alexios I Komnenos reportedly invented new pieces of heavy artillery which deviated from the conventional design and made a deep impression on everyone. 1 (1995) Introduction: Traction trebuchets were medieval rotating-beam siege engines; they were powered by a human team pulling ropes and hurled stone projectiles from a sling. If the washers start falling off, rub a little bit of hot glue on the outside of the axle and the washer to keep them in place. The payload could be thrown a far distance and do considerable damage, either by smashing down walls or striking the enemy while inside their stronghold. Make someone happy. [72], The earliest solid reference to a "trebuchet" in European sources dates to the siege of Castelnuovo Bocca d'Adda in 1199. Floating Arm Trebuchet. The first one built was a Floating Arm Trebuchet, made by Ron Toms. When you make a purchase through these links, I may earn an affiliate commission at zero cost to you. Hello, Sign in. then math, engineering and economics. The projectile is thrown when the beam is quickly rotated by applying force to the opposite end of the beam. Notify administrators if there is objectionable content in this page. Also, the Golf Ball Beast lifts the back of the frame just before the arm is released. Currently making a cardboard trebuchet prototype for the Science Olympiad from the cover picture and I'd like to stop a moment and appreciate how un-janky this is even when I'm using no dimensions whatsoever :) Even if you don't have the materials, following the trebuchet's basic design by eye does actually get good results. After initial shots, we tried to optimize our throwing distance. It's our goal to provide the toys that make it easy. Our counter weights were made out of concrete and had a mass of 40 kg (88 lb). [144], In 2013, during the Syrian civil war, rebels were filmed using a trebuchet in the Battle of Aleppo. There are two main types of trebuchet. These factors multiply the acceleration transmitted to the throwing portion of the beam and its attached sling. The difference between counterweight and traction trebuchets is what force they use. English Deutsch Franais Espaol Portugus Italiano Romn Nederlands Latina Dansk Svenska Norsk Magyar Bahasa Indonesia Trke Suomi Latvian Lithuanian esk . 5 years ago, what is the exact number of washers on each side of the bolt, Reply While the trebuchet is bieng launched, time the throw from when the projectile leaves the sling to when it hits the ground. Set-up some cans and knock them down, just to see if In these instances, trebuchets were used to threaten or bombard enemy fortifications and ensure victory. Despite its greater range, counterweight trebuchets had to be constructed close to the site of the siege unlike traction trebuchets, which were smaller, lighter, cheaper, and easier to take apart and put back together again where necessary. Find out what you can do. [19], A trebuchet projectile can be almost anything, even debris, rotting carcasses, or incendiaries, but is typically a large stone. This is the floating arm trebuchet with a sling. It is built on the design of a similar trebuchet at Middelaldercentret in Denmark. How's that for a reason? Floating Arm Trebuchet Page 1 of 3 1 2 3 Last. The term traction trebuchet was created mainly to distinguish this type of weapon from the onager, a torsion powered catapult that is often conflated in contemporary sources with the mangonel, which was used as a generic term for any medieval stone throwing artillery. Of these models, the mathematical model of each was determined. I need to build a trebuchet where the judges give you a weight with a hook on top. [131][132] In the episode "Carnage A Trois" in series 4 of The Grand Tour the presenters uses a trebucet to allegedly sling a Citron C3 Pluriel from the White Cliffs of Dover across the English Channel. Basically, it gets a lot of energy for it's size and weight, and uses it very well, but there are many challenges. [71] Chevedden argues that given the references to new and better trebuchets that by the 112030s, the counterweight trebuchet was being used in a variety of places by different peoples such as the crusader states, the Normans of Sicily and the Seljuks. Thingiverse is a universe of things. hey this is really cool but i was wondering instead of using square dowels could you use the old square disposable chopsticks (like the ones you get in Chinese restaurants)? Categories for minibike_patrol with head word unit: special:unit, Category Nuances matching unit: legislative, grammatical, individual, social, orthographic, natural . The design forces the counterweight to fall in a semi circular arc rather than a vertical arc making it lose some if its power. -Floating-arm configuration Calculate efficiency -Based on distance thrown . 36, No. From the First Crusade (10961099) onward, there does not appear to be any discernible difference in the technology of siege engines employed by Muslim and Frankish forces, and by the Third Crusade (11891192), both sides seemed well acquainted with the enemy's siege weapons, which "appear to have been remarkably similar. Question It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the 13th century. Get some exercise. This is the most effecient catapult design known today. Peter Purton suggests that this was simply because the machines became larger. Create the drop channel: Hot glue four square dowels upright at the center of the base. [63][64] Hanging counterweights hang below the arm and drop vertically. Below is a picture of the first FAKA ever made with the important parts which are shown labeled. Append content without editing the whole page source. The angle of the bend in the paperclip will determine the timing of the projectiles release. The bombardment lasted for hours, but the operators were inaccurate and most of the shots missed their target. However it is unclear if this referred to counterweight trebuchets since the author did not specify what engine was used and described the machine as fairly light. It stands for Floating Axle King Arthur. One hole should be near the end of the dowel, and the other three are spaced 1" (2.5 cm) apart, starting 2" (5 cm) from the first hole. The illustration above gives a diagram of a "floating-arm" trebuchet. [96] The Templar of Tyre described the faster firing traction trebuchets as more dangerous to the defenders than the counterweight ones. Step 1: Cut lumber. The floating arm trebuchet is a counterweight siege weapon which is a modern variation of the medieval trebuchet. Both Liang and Needham note that the illustrations are poorly drawn and confusing, leading to mislabeling. "It'sThe Hurl itself that matters! 3. If you want to discuss contents of this page - this is the easiest way to do it. [10] Other terms, such as machina maior/magna, might have also referred to counterweight trebuchets. He is barely holding the man's sword arm at bay but the other hand . Insert a 2" (5cm) piece of round dowel into one of the remaining holes. This will be the roller that travels over the glide rails. King James I of Aragon employed this as a defensive tactic in many fortified structures and towns which proved effective. The attempt was reportedly unsuccessful: the first projectile landed on the trebuchet itself, destroying it. A pair of wheels allows the arm to roll along I know a 13 year-old who will have some fun with this one. This is a more efficient way to transfer potential energy into kinetic energy at a small scale. The FAKA is very efficient for its frame height and arm length as well. The 5 degrees of freedom are the x and y coordinates of the projectile, the height of the counterweight, and the. Floating Arm Trebuchet Case Studies http://www.rlt.com/10121. As mentioned, the angle of the paperclip is a key variable, as well as the type of projectile, and the length of string that its attached to. Floating Arm In this design the counterweight is constrained by a track to fall dead vertical, and the entire throwing arm, running on wheels set in a horizontal track, shifts to accomodate the counterweight. And MightyB, an 8 ounce arm isn't that light. The treb built for this guide is slight different, partly due to design and partly due to the materials that I had to work with, e.g. The word trabuchellus appeared alongside manganum and prederia in a document in Vicenza on 6April 1189 (833 years ago)(1189-04-06). Of course, when properly tuned, there is very little energy left (The FAKA can be tuned for very high efficiency), but before its tuned, or in the event of a misfire things can go quite wrong. Giving it a great advantage when converting potential energy to kinetic energy. Trebuchets were still used both at the siege of Burgos (14751476) and siege of Rhodes (1480). It was a common powerful siege engine until the advent of gunpowder. [44] The Life of Louis the Pious contains the earliest western European reference to mangonels (traction trebuchets) in its account of the siege of Tortosa (808809). Qiang died the following year and no further references to the Arresting Trebuchet appear. Change the name (also URL address, possibly the category) of the page. . This key difference makes the trebuchet much more durable, allowing for larger and more powerful machines. Would you know the efficiency of the machine? The hinged trebuchet achieved efficiencies of 0.8065 for both range and energy efficiency and the "see-saw" with efficiencies of only 0.567 and 0.570, respectively. What's the material? The oddity with this trebuchet is that it has no arm ratio as the counterweight sits at the very end of the arm, and the arm itself tends to be shorter. [81], The counterweight and traction trebuchets were phased out around the mid-15th century in favor of gunpowder weapons. [97] The Song dynasty described countermeasures against counterweight trebuchets that prevented them from damaging towers and houses: "an extraordinary method was invented of neutralising the effects of the enemy's trebuchets. [100], The hand-trebuchet (Greek: , cheiromanganon) was a staff sling mounted on a pole using a lever mechanism to propel projectiles. (Velocity and Acceleration of a Tennis Ball). Check out how this page has evolved in the past. You are using an out of date browser. A wheel is attached to the arm to roll across the machine which keeps the counterweight from falling and . The arm should smoothly swing forward as the counterweight falls. Trebuchets compete in one of the classifications of machines used to hurl pumpkins at the annual pumpkin chucking contest held in Sussex County, Delaware, U.S. Price: $195.00 Click here to see our complete line of models and kits. According to the Song of the Albigensian Crusade, the defenders "ran to the ropes and wound the trebuchets", and to shoot the machine, they "then released their ropes. Seriously, get some toys, go outside and play. Bryce Lowe. If it does not, the arm will slam into one then the other before it is released. concentration. [128] In 1989, Middelaldercentret became the first place in the modern era to have a working trebuchet.[128]. The space between the dowel pairs across the base is 1 1/2" (4 cm). Armies employed a magister tormentorum ('master of trebuchets') for the reconstruction of trebuchets after they were deconstructed for transportation to their destination, whether on carts or by ship. Get ready to assemble the counterweight and trebuchet arm. PDF fileOperation Trebuchet: Efficiency of the Floating Arm Tyler Thibodeau, Drew Prosser, Kevin Chan, and Jack Stevenson 31. Create the trigger by tying one 30" (76 cm) piece of string to two 2" (5 cm) pieces of bamboo skewer. Did you make this project?

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floating arm trebuchet efficiency