The Tormentorum P-CCXXXVIII won the Armor and Weapons category at the Northern Lights Arts and Sciences Pentathlon hosted by the Shire of Panther Vale on March 24th, 2001. The following, regrettably text-heavy, documentation was submitted with the entry. It is provided here for the benefit any who might be interested in the subject, and perhaps to demonstrate to judge R. B. that, though mislaid, the documentation was not altogether neglected . . .

 Trebuchets were once the ultimate weapons of siege combat. In widespread use throughout the Dark Ages, they were often erected beyond the effective range of enemy archers, and used to reduce castle walls to rubble. Far superior in power and accuracy to the catapult, the largest specimens were reported to throw 250 pound stones as far as 300 yards. For centuries, their development drove the design of ever greater fortresses, and their use was the very definition of siege warfare. Many of Europe's greatest cities, even Paris1, once bore the unkind ministrations of the Grand Tormentor2 and his massive siege engines, as History itself still bears their mark. The only ancient trebuchet known to have survived to modern times was as quickly dismantled by the peasants who discovered it, and used for firewood3.

As a result, much of what we know about their construction and use necessarily comes to us from such illustrations as this excellent 14th century example4:

 While the Tormentorum P-CCXXXVIII was inspired by this illustration, much of its detail is conjectural. Its exact proportions were laid out with the assistance of a computer generated mathematical model, then verified and refined through the use of a functional prototype. Contrary to conventional wisdom, its main pivot is not connected rigidly to the throwing arm, so that I might test my own theories regarding the stabilizing effects of the inertial moment of the counterpoise. It was otherwise designed to be an attractive and safe means to demonstrate an ancient science. Its frame and laminated throwing arm are both constructed entirely of white ash, and its stacked metal counterpoise is appropriately of brass.

The Tormentorum P-CCXXXVIII is capable of throwing a 150 grain jumbo walnut a distance of 25 feet. Placed in proper perspective with the length of its throwing arm and the weight of its counterpoise, that's a scale representation of a 250 pound stone, being thrown 300 yards, against a gilded sky.

 Notes on design:
The Tormentorum P-CCXXXVIII was built in support of research into the design detail of the medieval trebuchet. By constructing such a tiny siege engine, a meaningful quantity of test data could be generated under controlled conditions, and in a cost-effective manner. The results of this research effort will be published under a separate cover.

In order to be useful as a test instrument, the Tormentorum P-CCXXXVIII had to approximate an authentic trebuchet in general proportion and detail. An appropriate relationship between size, weight, and performance was also maintained in order to reasonably allow reverse scaling of test results.

To begin with, a late-Medieval illustration of a trebuchet was selected as a general design guide. This was accomplished by reviewing available illustrations against a selection criteria which included simplicity of design, completeness of detail, and reference to an actual battle to reduce the odds of choosing an entirely fictional design. The selected illustration, "Von Trostberg's Castle is besieged", rated well in simplicity and authenticity, and about as can be expected in completeness of detail.

Next, a preliminary design configuration for the new trebuchet was laid out. The performance and efficiency of a trebuchet is highly dependent on the relative lengths and weights of its various limbs, but the evolutionary refinements represented in the proportions of the late model trebuchet are only poorly expressed in most contemporary illustrations. It was hoped that the use of mathematical modeling would allow a similar evolution to take place during the preliminary design phase, and would lead to the design of a respectably efficient trebuchet.

 MacTreb, a computer based mathematical model created by Donald B. Siano7 was chosen for this effort. This well documented program was written in RealBasic,and was run on an Apple iMac. The apparent proportions of the trebuchet at Von Trostberg's Castle were used as initial input, and were then optimized for improved efficiency, and scaled down into the preliminary design configuration.

The preliminary design configuration was verified by testing a breadboard model constructed from available materials. This very expedient model was sufficient to demonstrate the potential range of the proposed design, but of course lacked many of the authentic details which are likely to have influenced other aspects of performance. The final design was therefore completed, based upon the verified preliminary configuration.