Trebuchet Ballistics

animation

front beam (cm)

45

back beam (cm)

120

sling length (cm)

50

sling angle at release of projectile

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projectile weight (kg)

3

air drag coefficient

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counterweight (kg)

45

rope length (cm)

60

The trebuchet is a medieval rock-launching catapult used to destroy enemy fortresses. The basic principle is the conversion of the potential energy of a falling counterweight into the kinetic energy of an escaping projectile. The projectile fits in a pouch hanging on a sling. It is released by the operator at a critical moment to start its ballistic flight. The path of the projectile consists of two phases:

Phase 1: The projectile is inside the pouch on the sling of the trebuchet and follows the equations of motion used in the Demonstration listed in Related Links. It is based on the method described in [1].

Phase 2: After release from the trebuchet sling's pouch, the projectile follows a ballistic path subject only to gravity and air drag. The equation of motion of this part is described in [2].