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Mechanical Blog


Catapult


PCP

A catapult is a ballistic device used to launch a projectile a maximum distance without the using of any other explosive devicesThe word 'catapult' comes from the Latin 'catapulta'


particularly various types of ancient and medieval siege engines. Although the catapult has been used since ancient times, it has proven to be one of the most effective mechanisms during warfare. Now days the term can apply to devices ranging from a simple hand-held implement (also called a “slingshot” ) to a mechanism for launching aircraft from a ship


The grate event of the catapult was taken in College of polytechnic in Pimpri Chinchwad in 2017 several student was participated in this event this was an inter college event .student enjoyed as well as they understand the importance of this catapult


Modern use

Military

The last large scale military use of catapults was during the trench warfare of World War I. During the early stages of the war, catapults were used to throw  hand grenades  across no man's land into enemy trenches. They were eventually replaced by small mortars.


In the 1840s the invention of  vulcanizedrubber allowed the making of small hand-held catapults, either improvised from Y-shaped sticks or manufactured for sale; both were popular with children and teenagers. These devices were also known as  slingshots in the USA.


Special variants called aircraft catapults are used to launch planes from land bases and sea carriers when the takeoff runway is too short for a powered takeoff or simply impractical to extend. Ships also use them to launch torpedoes and deploy bombs against submarines.[dubious – discuss] Small catapults, referred to as "traps", are still widely used to launch clay targets into the air in the sport of clay pigeon shooting.


Until recently, catapults were used by thrill-seekers to experience being catapulted through the air. The practice has been discontinued due to fatalities, when the participants failed to land onto the safety net.[37][38]  Human cannonball circus acts use a catapult launch mechanism, rather than gunpowder.


Early launched roller coasters used a catapult system powered by a diesel engine or a dropped weight to acquire their momentum,[40] such as Shuttle Loop installations between 1977-1978. The catapult system for roller coasters has been replaced by flywheels and later linear motors.


Pumpkin chunking is another widely popularized use, in which people compete to see who can launch a pumpkin the farthest by mechanical means (although the world record is held by pneumatic air cannon).


Medieval catapults



Castles and fortified walled cities were common during this period and catapults were used as siege weapons against them. As well as their use in attempts to breach walls, incendiary missiles, or diseased carcasses or garbage could be catapulted over the walls.


Defensive techniques in the middle Ages progressed to a point that rendered catapults largely ineffective. The Viking siege of Paris (885–6 A.D.) "Saw the employment by both sides of virtually every instrument of siege craft known to the classical world, including a variety of catapults", to little effect, resulting in failure.



The most widely used catapults throughout the Middle Ages were as follows:[35]


Ballista


TBallistae were similar to giant crossbows and were designed to work through torsion. The projectiles were large arrows or darts made from wood with an iron tip. These arrows were then shot "along a flat trajectory" at a target. Ballistae were accurate, but lacked firepower compared with that of a mangonel or trebuchet. Because of their immobility, most ballistae were constructed on site following a siege assessment by the commanding military officer.


Springald


The springald's design resembles that of the ballista, being a crossbow powered by tension. The springald's frame was more compact, allowing for use inside tighter confines, such as the inside of a castle or tower, but compromising its power.


Mangonel


This machine was designed to throw heavy projectiles from a "bowl-shaped bucket at the end of its arm". Mangonels were mostly used for “firing various missiles at fortresses, castles, and cities,” with a range of up to 1300 feet. These missiles included anything from stones to excrement to rotting carcasses. Mangonels were relatively simple to construct, and eventually wheels were added to increase mobility.


Onager


Mangonels are also sometimes referred to as Onagers. Onager catapults initially launched projectiles from a sling, which was later changed to a "bowl-shaped bucket". The word Onager is derived from the Greek word onagros for "wild ass", referring to the "kicking motion and force"[35] that were recreated in the Mangonel's design. Historical records regarding onagers are scarce. The most detailed account of Mangonel use is from “Eric Marsden's translation of a text written by Ammianus Marcellius in the 4th Century AD” describing its construction and combat usage.

Mongol warriors using trebuchet to besiege a city


Trebuchet


Trebuchets were probably the most powerful catapult employed in the Middle Ages. The most commonly used ammunition were stones, but "darts and sharp wooden poles" could be substituted if necessary. The most effective kind of ammunition though involved fire, such as "firebrands, and deadly Greek Fire". Trebuchets came in two different designs: Traction, which were powered by people, or Counterpoise, where the people were replaced with "a weight on the short end". The most famous historical account of trebuchet use dates back to the siege of Stirling Castle in 1304, when the army of Edward I constructed a giant trebuchet known as Warwolf, which then proceeded to "level a section of [castle] wall, successfully concluding the siege".


Couillard


A simplified trebuchet, where the trebuchet's single counterweight is split, swinging on either side of a central support post.


Leonardo da Vinci's catapult


Leonardo da Vinci sought to improve the efficiency and range of earlier designs. His design incorporated a large wooden leaf spring as an accumulator to power the catapult.[d] Both ends of the bow are connected by a rope, similar to the design of a bow and arrow. The leaf spring was not used to pull the catapult armature directly; rather the rope was wound around a drum. The catapult armature was attached to this drum which would be turned until enough potential energy was stored in the deformation of the spring. The drum would then be disengaged from the winding mechanism, and the catapult arm would snap around.[Though no records exist of this design being built during Leonardo's lifetime, contemporary enthusiasts have reconstructed it.

Prof.Chetan Chimote

Mechanical Department

Pimpri Chinchwad Polytechnic

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