Daniel Wang's Honor's Physics Blog: Catapult Project

HISTORY OF CATAPULT

Catapults have been an essential part of warfare since the middle ages, with various types having been used by the Greeks, Romans, and Chinese. Early prototypes were attempts to increase the range and power of a crossbow. The first documented was the use of a mechanical firing catapult (early Ballista) in 399 BC by Diodorus Siculus, a Greek historian. Modern catapults made theirs appearance in Europe around the Middle Ages during the Siege of Dover in 1216 (the French crossed the Channel and were the first to use catapults on English soil). With war being widespread throughout all of Europe, catapults became an important part of war, for they were able to launch projectiles (including human bodies) at city walls, to destroy their protection, or over them to completely devastate a city. All in all catapults were in use until around 885-886 AD when newer technology rendered them useless. During their reign as a warfare powerhouse, three main types of catapults were in use.

Ballista: The Ballista is basically a giant crossbow and the earliest of all catapults. Believed to have been invented by the Greeks and then later adapted by the Romans, the Ballista consisted of two wood arms attached to a piece of rope (usually human hair or animal sinew). The rope was attached to a winch and once pulled back, cause the bending of the arm. The Ballista could shoot an arrow with deadly accuracy, however, it lacked power compared to the others. Additionally, the springald was basically a smaller version of the Ballista, mainly used for antipersonnel reasons.

Mangonel: Invented by the Romans in 400 BC, the Mangonel is what people think when thy think of a catapult. The catapult has a long wooden arm attached to a bucket/container with a rope attached to the end. From a 90 degree angle, the arm is pulled back to build tension and store energy in the rope and arm. Once released, the arm shoots back into the original position, but the inertia of the projectile causes it to continue moving forward. The Mangonel shot objects in an overhead arc and was capable of launching up to 1,300 ft. The Onager, a type of Mangonel, had its name derived from the Latin word "onagros" meaning wild ass, since the motion and power of the catapult mimicked the kick of a wild ass.

Trebuchet: This catapult was designed for maximum force, for the stones it hurled were meant to demolish city walls. Believed to be created by the Chinese in 300 AD, the Trebuchet arrived in Europe around 500 AD. The catapult consisted of a long arm (up to 60 ft) balanced on a fulcrum far from the center. A shorter arm was attached to a counter balance; a heavy lead weight. A sling is attached to the end of a long arm and a rope is attached to the long arm and pulled down until the counter balance was high in the air. The potential energy is stored in the counterbalance and when the rope is released, the counterbalance plunges straight down. The potential energy is then converted into kinetic energy and when the rope is brought to a stop, the projectile continues to move. The Trebuchet was the most feared and hated siege weapon and those who manned the catapult were called "gynours". The most powerful and famous Trebuchet was the WarWolf designed and constructed by Master James of St. George.

MY CATAPULT:

While building my catapult, I ran into two problems

1) The trigger mechanism prevented a fluid motion for the lever.

it continually got in the way, and so I had decided to move it.

Thus, allowing the lever to snap forward in a more efficient manner.

2) The snapping of the lever was too strong for the plastic spoon, and after several attempts, the plastic spoon began to crack. I was able to solve this problem by adding duct tape, which could cushion the hitting force and act as a protective layer around the spoon.

PROCESS