Trebuchet Lab Report

Introduction

Medieval Trebuchet (Britannica).

The invention of projectile launching siege weapons such as the trebuchet dates to 300 BCE, in China. These huge artillery pieces could demolish castle walls through the employment of projectiles of immense masses. Their usage facilitated different tactics and greater scales of warfare. This utilisation of projectiles is a testament to human ingenuity, as it has withstood the test of time and is still present within modern warfare. In addition to this application however, the construction of millennia old siege weapons provides insight into some of the fundamental laws of motion. Despite them being rendered obsolete, their construction provides the opportunity to observe these laws in a tangible

Firstly, the design of the trebuchet demonstrated significant flaws in testing, this being a large factor in it’s subpar results. The sling was unable to complete a full arc, and often released the projectile at height lower than its apex, and at a significant angle. The motion of the sling was haphazard and non-uniform as a result, and the projectiles' release was as such. The trebuchet tended to lean forwards because of the positioning of the counterweights. This altered the beneficial motion provided by the wheels, which was a contributing factor in the limited range of the projectile. Stabilisation was provided by an object placed beneath the base. Additionally, the positioning of the counterweights along their respective arm was likely too close to the rotational center of the trebuchet. Meaning, the aforementioned optimal ratio of counterweight to projectile arm was not achieved, and not enough energy was transferred along the arm to the sling. Conversely, the usability of the trebuchet relative to its functionality was optimal. The trigger mechanism provides an intuitive and safe method of launching the trebuchet. The loading mechanism of the sling is simple with little variation possible. The structural integrity of the design was sound. It maintained its capacity to complete firing trials, even with the additional strain likely placed on the frame resultant of the trebuchets tilt. Numerous trials were completed with the design, and no components of the trebuchet broke, or needed to be replaced. The only foreseeable repair that may be required is the replacement of the frictionless tape applied to the dowel on which the arm rotates. Repeated trials may prove to wear this down. The experimental error of the trebuchet can be calculated using this formula: Experimental Error % = (theoretical value-measured value)/(theoretical value)100