Sure thing. The counterweight is the heart of the trebuchet, just like a sword’s hilt. It’s a large block of stone or iron that hangs on the short arm of the lever. When you raise that arm, the weight pulls down, and the long arm shoots up, throwing your projectile. The key is the ratio of arm lengths—longer the throwing arm, higher the trajectory. The weight must be heavy enough to overcome the arm’s inertia, yet light enough that the release isn’t too violent; a misbalance would mean a short, low throw or even a broken arm. In short, it’s a simple lever, but the medieval engineers had to get the maths right to make it work. Happy to go deeper if you want.

They weren’t all in one camp. The great catapults of the Crusades had a fixed angle, because a simple hinge made construction easier, and the builders had a rough idea that a 30‑40 degree throw was good enough. But later, in the 14th‑century, engineers started playing with the lift arm’s slope. By adjusting the counterweight’s position along the short arm they could change the release angle. It wasn’t a pure experiment, but they did test different pitches on a few prototypes before settling on a design that fit the siege’s need. So yes, some kept a single angle, others treated it as a variable to tweak performance.

Sure, let’s keep it simple. Torque equals weight times lever arm. A 120‑kg counterweight is about 1,176 newtons (120 kg × 9.8 m/s²). If the short arm is, say, 4 m long, the torque on the pivot is 1,176 N × 4 m = 4,704 N·m. The long arm is 30 m, so when that arm rises it’s carrying the same torque, but the angular velocity is higher. The torque curve starts at that 4,704 N·m when the counterweight is at its lowest, then decreases as the weight rises, until it’s zero right before release. The engineer would have to balance that against the sling’s own weight and the projectile, but that’s the basic shape. It isn’t a smooth curve—there’s a steep drop as the weight lifts—so the timing of the release is crucial.

Indeed, the great engineers had to rely on touch and trial. The hinge on the release latch would be a simple wooden cam; when the counterweight’s torque dropped enough, the cam would slip and give a sharp click. That click was their cue to pull the rope. They did repeat trials to find the exact angle, then locked the latch in place for the siege. No digital feedback, just bone‑deep precision and a stubborn trust in a well‑tuned lever.