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Ancient Engineering
Trebuchet
So what's a catapult? Review
Catapults can be split into three categories:
● Traditional Catapult
● Ballista
● Trebuchet
Trebuchet
A trebuchet launches a projectile from a sling
on a pivoting beam.
History
The 1st catapults, designed by
the Greeks and Romans, date
back to the 4th century BC.
Traction trebuchets origina...
History
We will be focusing on
counterweight
trebuchets, first designed
in the 12th century.
History
Descendents of the first
Chinese trebuchets, these
siege weapons resulted
from advancement by the
Islam and Byzant...
How they work
A counterweight
rotates the beam
through an arc
that releases the
projectile.
Trebuchet
The counter weight is hoisted into air and is held in
place, usually by a release system attached to the
opposit...
Trebuchet
Release system activated.
Counter weight drops, swinging arm with sling
attached.
Trebuchet
As sling follows its arc, one end is released
Trebuchet
Trebuchet
Can you guess some of the main factors that
affect trebuchet performance?
Major factors to consider
● Counterweight Mass
● Counterweight Height
● Projectile Mass
● Sling Length
● Launch Angle
● Wh...
Simulation
Let’s see how some of these factors affect performance!
www.globalspec.com/trebuchet/
How they work
● It is powered by gravity.
● Generally, its force is equal to “4 to 6 times
of the counterweight arm’s leng...
Review: Gravitational Potential Energy
The gravitational potential
energy of an object can be
found by multiplying the
wei...
Gravitational Potential Energy
Energy stored by
trebuchet is determined
by:
● Weight of Counter
Weight
● Height Counter We...
How they work
● It is powered by gravity.
● Generally, its force is equal to “4 to 6
times of the counterweight arm’s leng...
Energy
Gravitational energy stored by hoisted counter
weight is translated into rotational kinetic energy of
the sling on ...
Rotational Kinetic Energy
The rotational kinetic
energy is dependent on the
length of the arm and the
weight of the counte...
Rotational Kinetic Energy
Force: the weight of the
falling counter weight
Fulcrum
Distance
How they work
● It is powered by gravity.
● Generally, its force is equal to “4 to 6 times
of the counterweight arm’s leng...
Sling
The sling releases
when a certain angle α
is reached. At this point
the ring connected to
the sling slips off and
th...
Sling
Here we get the
second fulcrum.
Virtual Trebuchet
http://www.virtualtrebuchet.com
A much more intricate simulator
Cd Trebuchet
You will get a chance to build this during lab.
YEOT Spring 2015 Webinar 5: Catapults and Trebuchets
YEOT Spring 2015 Webinar 5: Catapults and Trebuchets
YEOT Spring 2015 Webinar 5: Catapults and Trebuchets
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YEOT Spring 2015 Webinar 5: Catapults and Trebuchets

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Please find all materials, webinars, and links here http://coffeeforthebrain.com/yeot/

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YEOT Spring 2015 Webinar 5: Catapults and Trebuchets

  1. 1. Ancient Engineering Trebuchet
  2. 2. So what's a catapult? Review Catapults can be split into three categories: ● Traditional Catapult ● Ballista ● Trebuchet
  3. 3. Trebuchet A trebuchet launches a projectile from a sling on a pivoting beam.
  4. 4. History The 1st catapults, designed by the Greeks and Romans, date back to the 4th century BC. Traction trebuchets originated in China and date back to around the same time.
  5. 5. History We will be focusing on counterweight trebuchets, first designed in the 12th century.
  6. 6. History Descendents of the first Chinese trebuchets, these siege weapons resulted from advancement by the Islam and Byzantium civilizations and further development in Western Europe.
  7. 7. How they work A counterweight rotates the beam through an arc that releases the projectile.
  8. 8. Trebuchet The counter weight is hoisted into air and is held in place, usually by a release system attached to the opposite end of the arm. Counter weight Release system
  9. 9. Trebuchet Release system activated. Counter weight drops, swinging arm with sling attached.
  10. 10. Trebuchet As sling follows its arc, one end is released
  11. 11. Trebuchet
  12. 12. Trebuchet Can you guess some of the main factors that affect trebuchet performance?
  13. 13. Major factors to consider ● Counterweight Mass ● Counterweight Height ● Projectile Mass ● Sling Length ● Launch Angle ● Wheels vs. hinged counterweight
  14. 14. Simulation Let’s see how some of these factors affect performance! www.globalspec.com/trebuchet/
  15. 15. How they work ● It is powered by gravity. ● Generally, its force is equal to “4 to 6 times of the counterweight arm’s length” ● The sling acts as a secondary fulcrum.
  16. 16. Review: Gravitational Potential Energy The gravitational potential energy of an object can be found by multiplying the weight of the object by how high it is off the ground. PEGravitational = weight * height
  17. 17. Gravitational Potential Energy Energy stored by trebuchet is determined by: ● Weight of Counter Weight ● Height Counter Weight is hoisted
  18. 18. How they work ● It is powered by gravity. ● Generally, its force is equal to “4 to 6 times of the counterweight arm’s length” ● The sling acts as a secondary fulcrum.
  19. 19. Energy Gravitational energy stored by hoisted counter weight is translated into rotational kinetic energy of the sling on the arm
  20. 20. Rotational Kinetic Energy The rotational kinetic energy is dependent on the length of the arm and the weight of the counterweight. This is because of torque, or rotation around a fulcrum **In this case, the force is the weight of the falling counter weight **
  21. 21. Rotational Kinetic Energy Force: the weight of the falling counter weight Fulcrum Distance
  22. 22. How they work ● It is powered by gravity. ● Generally, its force is equal to “4 to 6 times of the counterweight arm’s length” ● The sling acts as a secondary fulcrum.
  23. 23. Sling The sling releases when a certain angle α is reached. At this point the ring connected to the sling slips off and the projectile is launched.
  24. 24. Sling Here we get the second fulcrum.
  25. 25. Virtual Trebuchet http://www.virtualtrebuchet.com A much more intricate simulator
  26. 26. Cd Trebuchet You will get a chance to build this during lab.

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