"Virtual Hurling"
Trebuchet Simulators

Building a trebuchet from scratch and finding the best proportions, weights, angles etc by trial and error certainly works ..well, that's how the Grey Co's first machines were done... but if you could model the rock-throwing beasts mathematically then think of the work and possibly wasted effort you could save.

Writing a good trebuchet simulator has been a project attempted by several hurling mathematicians - but the simplicity of the trebuchet's basic layout can be a little misleading. The complexity of the machine's motions on motions means that the mathematics gets pretty daunting rather quickly.
Phrases like "simultaneous differential equations" get used..

To simulate a real-world situation in a mathematical model you need to make some assumptions and set limits. All simulations do this, so check whether the assumptions made are appropriate to the machine you are interested in.

"The Algorithmic Beauty of Trebuchets"

This site was created by Donald B. Siano. It has versions of his fine simulation of a hinged-bucket trebuchet to suit almost everybody’s computer situation and computing inclinations. This style of trebuchet is the traditional one powered by a box-of-rocks hanging from the short end of the beam.
There is a Javascript-based calculator, a simulator using Mathematica, an Adobe Acrobat document with lots of trebuchet information - plus listings for the simulator in Basic, Fortran and C ... unbeatable!
This is probably the best simulator for traditional trebuchets available.

Trebuchet for Windows ("Wintreb")

This program used to be downloaded from the site of Civil Engineering Software. It was developed by Major Steven J Ressler of the Civil Engineering Division of the Department of Civil and Mechanical Engineering, United States Military Academy, West Point.
It is something of a classic among trebuchet simulators and led the way for many other attempts.
Wintreb assumes that the counterweight is rigidly attached to the beam, rather than sitting in a free-swinging bucket. This is certainly true of a number of modern reconstructions, and there's also a few Medieval drawings (but not many) showing this style.

Although Civilsoft no longer support this venerable simulation program, it still exists out there and this link will take you to one of its "foster homes" - Leeds University.

There are other quality trebuchet simulators out there, and I'll add them to this specialised links page when I can. If you know of one that you think that other trebuchet fans would find useful, please email me with the details.

Last Edited: Oct 2000
© Russell Miners 2000.
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