Designing airframes and engines to reduce the noise
The design of airframes and engines has improved a lot since the first jets started flying. Early jets have all been phased out and replaced by newer, quieter aircraft.
Airframe design improvements have focused on reducing the amount of friction and turbulence that occurs as air passes over an aircraft’s wings and fuselage, the source of aircraft noise.
For example, on some of its newer generation B737s, Boeing has introduced ‘advanced-technology winglets’ to the end of the wings, which reduce aerodynamic drag. Boeing reports that this reduces the area affected by noise by 6.5%.
Airbus has developed a new way of reducing engine fan noise, which is used in the new A380, and has also developed software which can work out the quietest way to take off or land, based on how much noise a specific journey is making on the ground.