The Challenge

To build a vehicle to drive to the launch square and fire your ball (missile) as far as possible.

The science involved

Energy transfer and acceleration

Throwing an object is all about energy transfer and acceleration. Energy has to be transferred from the launch system to the projectile (object being thrown), accelerating it to as high a velocity as possible. When maximum velocity has been reached, launcher and projectile must part company in such a way that the projectile continues on its way unhindered. This may sound high-tech, but it's what happens when you throw a cricket ball, for example.

All of the teams decided to build some form of catapult system on their vehicle. Below are some of the concepts. Teams built firing vehicles based on ballista's, catapults and crossbows.

trébuchet

A rotating-beam throwing engine (machine) based upon counterweight induced energy quickly rotating the arm about a pivot.

mangonel

catapult

The term 'catapult' is often used as a generic label for all throwing machines. In modern times it describes any system that launches an object from a platform. Military historians and reference works are not in agreement when the term 'catapult' is used to label a specifically configured medieval non-gunpowder weapon. As a specific weapon, the single arm, torsion-powered, stone-throwing engine shown here is frequently called a 'catapult'. This machine has its throwing arm's lower end inserted into twisted sinew and is held in torsion.

pierrière.	bricole.

The term 'pierrière' was also use as a generic expression for stone-throwing engines of any kind. The general convention is to use the term for the more simple forms. They generally operated on a rotating-beam and weight-assisted [bricole] principle -- the arm rotating about a pivot supported on an upright pole-frame-- and were traction-operated by men pulling on one end of the launching arm.

spring-engine

As the concept was simple, there were many variations of spring-engines. It was characterized by the main launching, or striking, arm being bent back and held under tension. When the arm was released, it struck and launched an arrow (like the image shown), it was a true direct-firing weapon. Some variations had the bent-back arm be a 'throwing-arm', topped with a sling or cup, from which stones and the like were hurled. These had a slight curved-trajectory, and performed as indirect-fire weapons, much like the catapults shown earlier.