"Balrog" after the wonderful monster (our Balrog, unfortunately, was not as visually impressive). Then for our final project we decided to focus on the siege weapons showcased in the movies.First, we started off watching the Lord of the Rings Trilogy. These movies became the inspiration for our project. First we built a drag racer and named it "Balrog" after the wonderful monster (our Balrog, unfortunately, was not as visually impressive). Then for our final project we decided to focus on the siege weapons showcased in the movies.
Originally we planed to do several different weapons. One idea was a model of the Roman Trireme: but we realized that the three sets of oars were going to rather complex. Also for this to have been interesting then the boat should have been able to float and move on the water. Unfortunately, Legos do not lend themselves well to creating an object of this shape, i.e. very narrow. Also the robot wouldn’t be very interesting…it would move around but nothing else.
So our next idea was to build a Ballista. After several repeated attempts to create one, the same problem kept cropping up, how to create tension on the two 'arms' of the ballista. The different materials used (rubber bands, hemp string, dental floss, kite string) were unable to be calibrated to the same amount of tension. So, one 'arm' would swing further and ha
rder than the other. After a day of trials, this idea was also killed.
Our final idea that was never made to production was the creation of a battering ram. While relatively simple, a hanging pendulum 
like object swinging in an A-frame, time ran out.
Thus, it was that we settled on only building our initial creation, a Trebuchet. The Trebuchet is an medieval siege weapon that throws large weights far distances. Typically it was used to bash castles to dust. The Trebuchet works by using a counterweight that is released, and as it is released a sling is thrown up and over the machine. This animation should give a sense of the way it works.
Thus, our idea was to use Legos. We found several sites documenting the building of trebuchets out of Legos. However, each variation had several things in common. Mainly, most of the trebuchets did not use any kind of winch. The trebuchet was primed by the use of the person's hand, which pulled down the arm with the sling till the counterweight was taught and then released the arm. This allowed for a relatively easy construction. If, perchance, a winch was used to pull down the arm and reset the counterweight, then the actual release of the winch and arm was still human controlled. The trebuchets were one and all directly managed by a human.
Our idea was to try and make the winching and releasing completely controlled by either handyboards or crickets. This idea proved to be a greater task then imagined.
Click here to view a photo album of different trebuchets.