Section 2
Physical calculations — the technical "why"
Required torque by angle for a 120 mm L/44 cannon (mass ≈ 1,800 kg, lever arm ≈ 1.8 m from trunnion).
Law of Moments
T = m · g · d · cos(θ)
T: torque (N·m) — m: mass (kg) — g: 9.81 m/s² — d: lever arm (m) — θ: elevation angle.
Realistic counterweight
T_residual = T × (1 − 92%)
A good counterweight reduces torque by ~92%, but it remains substantial (~2,500 N·m at horizontal).
| Angle | Gross torque required | Residual torque (92% counterweight) |
|---|---|---|
| 0° (horizontal) | 31 784 N·m | 2 543 N·m |
| 45° | 22 475 N·m | 1 798 N·m |
| 90° (vertical) | 0 N·m | 0 N·m |
➡️ The critical point is always horizontal (0°): that is where the required torque is maximum.
Interactive torque calculator
Cannon mass
1 800 kg
800 kg2 500 kg
1,8 m
0,8 m3 m
92 %
0 %98 %
0°
0°90°
Gross torque (0°)
31 784 N·m
Gross
Residual torque (0°)
2 543 N·m
Counterweight efficiency 92%
Torque curve by angle
Animation — cannon elevation
Cannon elevation 0° → 90°
Angle0°
Residual torque
2 543 N·m
Load state
Critical