How a Trebuchet works
Geoff Hale
MFET 3320 Machine Design
History – 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 trebuchet is thought to have
been invented in China between the 5th and 3rd centuries BC. The
device reached Europe around 500 AD.
How it works – A trebuchet is powered by a falling counterweight
acting through a beam acting as a lever. The trebuchet is cocked by
raising the counterweight(1). A trigger mechanism holds the
counterweight up. The sling is arranged horizontally in a trough
parallel to the beam, toward the counterweight, and the projectile
placed in its pouch. When the trigger is released, the counterweight
falls and the beam pulls the sling, at first horizontally along the
trough in the base of the frame(2). Soon after, the sling lifts off and
whips in an arc upwards(3). When the projectile moves close to the point where the taut sling
makes about a 45° angle with the horizontal(4), the free end of the sling slips from the hook, and
the missile flies free toward its target(5).
Equations to consider
Force F=ma
Torque =rF
Work W=fd
Power P=W/t
Potential Energy
PE=mgh
Kinetic Energy
KE=1/2mv^2
References
http://science.howstuffworks.com/question127.htm
http://www.algobeautytreb.com/trebmath35.pdf
http://en.wikipedia.org/wiki/Trebuchet
http://www.trebuchet.com/
Machine Elements and Mechanical Design 4th edition