The main types of Catapults

Here are the main types catapults, sorted by the source of power:

1. The Mangonel Catapult (Uses Torsion and Tension)
2. The Trebuchet (Uses Weight)
3. The Da Vinci Model (Uses both Tension and Gear)
4. The Ballista (A Giant Crossbow)
5. The Onager (Uses Torsion)

To minimize confusion, I will explain few things:

1. 
   

1. Almost all cultures have made some kind of a catapult, so there are dozens of different names for the same type of catapult. So it's the kind of force the catapult uses that's important, not the name.