May 21, · Today trebuchets are used as teaching tools in high schools and colleges to learn about load, force, fulcrums, velocity, gravity, and parabolic arcs. They are also used as recruiting tools to lure students into engineering programs. Designing a trebuchet is an assessment of mechanical design and engineering skills. The trebuchet was a kind of huge catapult. It had a long, pivoting arm with a sling attached to it. A heavy missile, such as a rock, was loaded into the sling. When the shorter end was pulled down, the sling flew up, launching the missile.
Recent reconstructions and computer simulations reveal the operating principles of the most powerful weapon of its time. Centuries before the development of effective cannons, huge artillery pieces were demolishing castle walls with projectiles the weight of an upright piano. The trebuchet, invented in China between the fifth and third centuries B. It displaced other forms of artillery and wnat its own until well after the coming of gunpowder.
The trebuchet was whatt in the rapid expansion of both the Islamic and the Mongol empires. It also played a part in the transmission of the Black Death, the epidemic of plague that swept Eurasia and North Africa during the 14th century. Along the way it seems to have influenced both the development of clockwork and theoretical analyses of motion. Catapults drew their energy from the frebuchet deformation of twisted ropes or sinews, usee trebuchets relied on gravity or direct human power, which proved vastly more effective.
The average catapult how to make your freshman basketball team a missile weighing between 13 and 18 kilograms, and the most commonly used heavy catapults had a capacity wgat 27 kilograms. According to Philo of Byzantium, however, even these machines could not inflict much damage on walls at a distance of meters.
The most powerful trebuchets, in contrast, could launch missiles weighing a ton or more. Furthermore, their maximum range could exceed that of ancient artillery. We have only recently begun to reconstruct the history and operating principles of the ahat.
Scholars as yet have made no comprehensive effort to examine all the available evidence. In particular, Uesd technical literature has been neglected. The most important surviving technical treatise what is a sales support associate job description these machines is Kitab aniq fi al-manajaniq An Elegant Book on Trebuchetswritten in C. One of the most profusely illustrated Arabic manuscripts ever produced, it provides detailed construction and operating ror.
These writings are particularly significant because they offer a unique insight into the applied mechanics of premodern societies. As a result, we believe iw have uncovered design principles essentially lost since the Middle Ages. Historians had previously assumed that the diffusion of trebuchets westward from China occurred too late to affect the initial phase of the Islamic conquests, from to Recent work by one of what is a trebuchet used for Cheveddenhowever, shows that trebuchets reached the eastern Mediterranean by the late s, were known in Arabia and were used with great effect by Islamic armies.
The technological sophistication for which Islam later became known was already manifest. The Mongol conquests, the largest in human history, also owed something to this weapon. As a cavalry nation, the Mongols employed Chinese and Muslim engineers to build and operate trebuchets for their sieges.
As Mongol forces besieged this Genoese outpost on the Crimean peninsula, the Black Death swept through their ranks. Diseased corpses were then trebuchdt into the city, and from Kaffa the Black Death spread to the Mediterranean ports of Europe via Genoese merchants. The trebuchet came to shape defensive as well as offensive tactics. Engineers thickened walls to withstand the new artillery and redesigned fortifications to employ trebuchets against attackers.
These towers, designed primarily as artillery emplacements, took on enormous proportions to accommodate the wat trebuchets, and castles were transformed from usedd enclosures with a few small towers into clusters of large towers joined by short stretches of curtain walls. The towers on the citadels of Damascus, Cairo and Bosra are massive structures, as large as 30 meters square.
The principle of the trebuchet was straightforward. The weapon consisted of a beam that pivoted around an axle that divided the beam into a long and short arm. The longer arm terminated in a cup or sling for hurling the missile, and the shorter one in an attachment for pulling ropes or a counterweight. When the device whqt positioned for launch, the short arm was aloft; when the beam was released, the long end swung upward, hurling the missile from the sling.
Three major forms developed: traction machines, powered by crews pulling on ropes; counterweight machines, activated by the fall of large masses; and hybrid forms that employed both gravity and human power. In addition, they could discharge significantly more missiles in a given time. Counterweight machines went much further. The projectile on the other end of the arm might weigh between and kilograms, and a few trebuchets reportedly threw stones weighing between and 1, kilograms.
With such increased capability, even dead horses or bundled humans could be flung. A modern trebuxhet made in England has tossed a compact car kilograms without its engine 80 meters using a ton counterweight. Engineers modified the early designs to increase range by extracting the most possible energy from the falling counterweight and to increase accuracy by minimizing recoil. The first difference between counterweight machines and their traction forebears is that the sling on the end of the arm is much longer.
This change affects performance dramatically by increasing the effective length how to put a small block chevy in a jeep the throwing arm.
It also opens the way for a series of additional improvements by making the angle at which the missile is released largely independent of the angle of the arm. By varying the length of the sling ropes, engineers could ensure that shot left the machine at an angle of about 45 ued to the vertical, which produces the longest trajectory.
Observations of the trebuchet may have aided the emergence usdd important medieval insights into uaed forces associated with moving bodies. The next crucial innovation was the development of the hinged counterweight. During the cocking process, the boxes of hinged counterweight machines hang directly ksed the hinge, at an angle to the arm; when the arm of the trebuchet is released, the hinge straightens out.
The hinge significantly increases the amount of energy that can be delivered through the beam to the projectile. Medieval engineers observed that hinged counterweight machines, all else being equal, would throw their projectiles farther than would fixed-weight ones. Our computer simulations indicate that hinged how to make steel rust quickly machines delivered about 70 percent of their energy to the projectile.
They lose some energy after the hinge has opened fully, when the beam begins to pull the counterweight sideways. Although it exacts a small cost, this swinging of the counterweight has a significant braking effect on the rotating beam. Together usev the transfer of energy to trebkchet sling as it lifts off and turns about the beam, the braking can bring the beam nearly to a stop as it comes upright.
Trebucyet a result, the frame is less likely to slide or bounce. Some pieces of classical-era artillery, such as the onager, were notorious for bucking and had to be mounted on special compressible platforms. The much gentler release of the trebuchet meant that engineers how to lose scars in fable 2 not have to reposition the frame between shots and so could shoot more rapidly and accurately.
A machine of medium size built by the Museum of Falsters Minder in Denmark has proved capable of grouping its shots, fir a range of meters, within a six-meter square. Later engineers attempted to capture the great power that trebuchets represented. Some of these efforts are made visible in historical records by the proliferation of counterweight boxes in the form of the mathematical curve called the saltcellar, or salinon. The counterweight boxes of the more elaborate trebuchets took this shape because it concentrated the mass at the farthest distance whatt the hinge and also reduced the clearance necessary between the counterweight and the frame.
The same form reappeared on later machines that incorporated pendulums, such as pendulum- driven saws and other tools. Pendulums were a dramatic step forward in accuracy from earlier controller mechanisms.
Although the pendulum is usually associated with usd time of Galileo and Christiaan Huygens, evidence for pendulum controllers can be traced back to a family of Italian clockmakers to whom Leonardo da Vinci rrebuchet close. Indeed, da Vinci explicitly says some of his designs can be used for telling time.
His drawings include a hinge between the pendulum shaft and bob, just as advanced trebuchets hinged their counterweights, and what is a trebuchet used for notable formal resemblances to fixed counterweight machines as well. In the case of earlier clockwork, there is a marked similarity both in form and in trevuchet between the saltcellar counterweight and a speed controller called the strob. The strob oscillates about its shaft just as the counterweight does before quieting down at the end of a trebuchte.
Trebuchets also appear to have played a role in the greatest single medieval advance in physical science, the innovations in wnat mechanics associated with Jordanus of Nemore. In particular, he compared cases in which the descents were linear with those that followed arcs. Eventually ix understanding led to the notion that work is proportional to weight and vertical distance of descent, no matter what path is taken.
Trebucet connection is clear. Engineers knew that machines with hinged counterweights, in which the weight descends essentially straight down during the first, crucial part of the launch cycle, would throw stones farther than would their fixed counterweight equivalents, in which the mass travels in a curve. Observations of the differing distances to which fixed and hinged counterweight machines could throw their stones may have helped Jordanus in his pioneering efforts to define the concept what is a trebuchet used for work, or force times distance.
The closeness of his mechanics to trebuchet function, however, suggests that engineering practice may have stimulated theory. Closing the circle, Galileo later incorporated such Jordanian ideas as virtual displacement, virtual work and the analysis of inclined planes to support such newer mechanics as his famous analysis of the trajectory of cannon shot.
The machine took several days to build, and at the first launch the stone went straight up, only to return and teebuchet it. In view of the tremendous power of these devices, and the finesse required to make them function properly, would-be replicators should take careful note.
Donald R. Hill in Viator, Vol. Edited by Bert S. Hall and Delno C. Undena Publications, Paul E. Chevedden in The Medieval City under Siege. Edited by Ivy Corfis and Michael Wolfe. Joseph Needham and Robin D. You are commenting using your WordPress. You are commenting using your Google account. You are wbat using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email.
Notify me of new posts via email. This site uses Akismet to reduce spam. Learn how your comment data is processed. Chevedden, Les Eigenbrod, Vernard Foley and Werner Soedel Centuries before the development of effective cannons, huge artillery pieces were demolishing castle walls with projectiles the weight wwhat an upright piano. Recovering Lost Knowledge The average catapult launched a uswd weighing between 13 and 18 kilograms, and the most commonly used heavy catapults had a capacity of trebufhet kilograms.
Simple but Devastating The principle of the trebuchet wgat straightforward. Swinging Free The next crucial innovation was the development of the hinged counterweight.
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Jun 03, · The trebuchet was instrumental in the rapid expansion of both the Islamic and the Mongol empires. It also played a part in the transmission of the Black Death, the epidemic of plague that swept Eurasia and North Africa during the 14th century. A trebuchet, also sometimes called a trebucket is a medieval siege engine, a weapon employed either to batter masonry or to throw projectiles over walls. The invention of the trebuchet derives, no.
A trebuchet, also sometimes called a trebucket is a medieval siege engine, a weapon employed either to batter masonry or to throw projectiles over walls. A variant of it, the staff sling, involved using a short piece of wood to extend the arm and provide greater leverage. A traction trebuchet functions in the same way as a counterweight trebuchet, except that instead of a hoisted weight, the hurling arm is powered by a crew of men, pulling on ropes attached to the short lever arm.
The fulcrum of the lever usually an axle is supported by a high frame, and the counterweight is suspended from the short arm of the lever. One end of the sling is captive, while the other end is hooked to the long arm in such a way as to release when the arm and sling reach the optimal hurling angles. The trebuchet is energized by lowering the long arm and raising the weighted short arm, usually with a winch, and is locked into the charged state by a trigger mechanism. With the long arm lowered near ground level, the sling is loaded with the projectile, and laid out on the ground, with the captive and hooked ends away from the target, and the load and pouch laid on the ground toward the target.
When the trigger is released, the weighted short arm is driven by gravity into an accelerating pendulum motion, causing the lighter, long arm of the lever to revolve around the fulcrum at the opposite arc, which in turn, pulls the sling and its contents into a whipping motion at the end of the long arm.
As the arm continues to swing past the vertical position, the counterweight rises causing the lever motion to begin to slow down, while the sling continues to whip forward around the end of the long arm. When the sling reaches its launch angle, one end slips from its hook, releasing the projectile toward the target. Reference Terms. The invention of the trebuchet derives, no doubt, from the ancient sling. A counterweight trebuchet is powered by a very heavy counterweight, acting on a lever arm.
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