6 Decibels For 0.5% Thrust: The Engine Trade-Off Boeing Made & Airbus Refused

Simple Flying

The distinctive sawtooth edges on several Boeing engine nacelles are more than a styling feature. Specifically, they are chevrons, a technology developed through NASA research to reduce the noise produced when hot exhaust from a jet engine mixes with surrounding air. Boeing adopted the concept on aircraft including the Boeing 787 Dreamliner , 747-8, and 737 MAX family, accepting a small aerodynamic penalty in exchange for a quieter departure footprint. NASA’s documented flight testing demonstrated meaningful noise reductions, while industry assessments have ultimately placed the thrust penalty at about a 0.5 percent reduction.

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