Which law is involved in the Torque Effect?

• A. Torque Effect
• B. Action/Reaction
• C. Inertia
• D. Gravity

Answer: (B)

The torque effect is a direct consequence of Newton's third law: for every action there is an equal and opposite reaction. When the engine drives the main rotor, it applies torque to the rotor. The rotor, in turn, applies an equal and opposite torque to the helicopter fuselage, causing the aircraft to yaw in the opposite direction. This yaw tendency is what anti-torque systems like the tail rotor counteract.

Understanding this helps explain why increasing rotor torque (via throttle or collective) makes the yaw more pronounced, and why anti-torque authority is essential for coordinated flight. The other concepts—gravity, inertia, or a standalone notion of torque—don’t capture the cause of the yaw in rotorcraft as directly as the action/reaction principle.