Boeing abandons chevrons on aircraft for fuel efficiency

Boeing has discontinued the use of chevrons, the serrated edges on engine nozzles, on its new aircraft due to a slight reduction in thrust and fuel efficiency. This design, intended to reduce engine noise, is no longer considered optimal. The chevrons, first used on the 737 MAX, generated vortices to mix exhaust flows, lowering noise levels. However, this design resulted in a small, but significant, fuel burn penalty, especially during takeoff and climb, impacting the 737 MAX's performance. Alternative noise reduction methods, such as new nozzle designs and improved sound insulation, are now favored. The 777X, for example, uses a new nozzle design, and Airbus has focused on nacelle construction for noise reduction, making chevrons obsolete.