Catapults

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Catapults - Engineering Week 2011 School Talk

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  • Catapults

    1. 1. Engineering Week 2011 Story of the Catapult History, Types, Physics and Model Building
    2. 2. Before the days of gunpowder, the military used large timber machines tothrow rocks, arrows and flaming barrels of tar at and into castles and forts. Inancient days, countries, towns and neighbours would often be at war, trying totake each others land, riches and treasure. To prevent attack from invaders,towns and wealthy land owners built forts and castles for protection. The fortshad very thick stone walls and were sometimes high on top of a hill orsurrounded by a moat. The walls had protected openings to shoot arrows andthrow stones and pour burning fat from, so attacking a castle was not an easyjob.
    3. 3. Despite the difficulty of attacking a castle, there was often war and somepeople within the military started to specialise in building machines andstructures to help in attacking castles. The builders of the machines calledsiege engines were some of the earliest engineers. About 2,500 years crossbows started to grow larger and more powerful and these developed intopowerful and heavy machines that could fling that could fling large projectilesat and over castle walls.The machines called catapults didn’t use explosives like today’s militaryweapons, instead they used energy stored in bent timber and sinew, twistedrope or heavy weights.What were some of the things that were tossed by catapults? stones, arrows,burning barrels, snakes, heads.
    4. 4. Catapult Timeline400BC - Early tension catapults that operate like large crossbows appear340BC - First torsion powered ballistae built in Greece146BC - Romans use over 400 onagers and ballista in a siege at Carthage380AD - Romans use slings on their torsion powered onagers500 - Gravity powered catapults appear in China600 to 900 - Gravity powered catapult technology move into Europe885 - Vikings besiege Paris using catapults1304 - Edward 1 of England builds Ludgar the War Wolf to defeat the Scots1400 - Gun powder and canon replacing catapults1480 - Last major use of catapults in a seige by Greeks against attacking Turks.
    5. 5. Types of Catapults or Siege Engine Ballistae
    6. 6. Onager
    7. 7. Trebuchet
    8. 8. Trebuchet
    9. 9. Catapult Power• pumpkin catapult record 620m (trebuchet)• largest trebuchet currently in operation 18m high
    10. 10. Catapult PhysicsEnergy Source• Tension spring• Torsion spring• GravityMechanisms• Lever - mechanical advantage• Pulley Wheel & axle

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