Which Army helicopter generates the high noise level?

Which Army helicopter generates the high noise level?

• A. UH-60 Black Hawk
• B. CH-47
• C. AH-64 Apache
• D. CH-53K

Answer: (B)

The main idea is how rotor design and power translate into sound. Noise from a helicopter largely comes from rotor aerodynamics—blade passage frequency, blade-vortex interactions, and downwash—as well as the power required from the engines to lift and maneuver. A large-diameter, high-power rotor system tends to create more intense noise, especially when the aircraft is hovering or carrying heavy loads. The CH-47 Chinook uses two very large, widely spaced rotor systems. That twin-rotor configuration, combined with powerful engines to lift heavy payloads, produces a strong acoustic footprint, with substantial blade passage and downwash noise. In this group, that makes it the helicopter most associated with higher noise levels. The other aircraft listed have loud characteristics too, but their configurations (single main rotor plus tail rotor, or different rotor geometry) generally result in a less pronounced overall noise signature in typical operations.

The main idea is how rotor design and power translate into sound. Noise from a helicopter largely comes from rotor aerodynamics—blade passage frequency, blade-vortex interactions, and downwash—as well as the power required from the engines to lift and maneuver. A large-diameter, high-power rotor system tends to create more intense noise, especially when the aircraft is hovering or carrying heavy loads.

The CH-47 Chinook uses two very large, widely spaced rotor systems. That twin-rotor configuration, combined with powerful engines to lift heavy payloads, produces a strong acoustic footprint, with substantial blade passage and downwash noise. In this group, that makes it the helicopter most associated with higher noise levels. The other aircraft listed have loud characteristics too, but their configurations (single main rotor plus tail rotor, or different rotor geometry) generally result in a less pronounced overall noise signature in typical operations.