A brief overview of aircraft noise and strategies to reduce it, including the causes of aircraft noise and the silent aircraft concept design.

1. AIRCRAFT NOISE
THE AERONAUTIC ORCS

2. OUR TEAM
• DJ
• Aidan
• Nick
• Saatvik
• Ryan
• Jean-Lou
• Tyler
• Josh
• Elliot

4. CAUSES OF AIRCRAFT NOISE
Aircraft noise is caused by a variety of factors, including the
engine, the airframe, the flaps, and the landing gear. The
engine noise is a major factor in the overall noise output of
an airplane, but the other factors also contribute. Aircraft
noise is a problem because it causes adverse health effects
and disrupts sleep.

5. ENGINE NOISE
Engine noise is the primary source of noise
pollution from aircraft. Engine noise is
controlled by modifying engines with devices
like hush kits and chevrons. Chevrons work by
smoothing the mixing of hot air from the
engine with cold air outside. This mixing
contributes to noise levels. Hush kit also work
to reduce engine noise and are mostly used
on older or smaller aircraft.
Hush Kit and Chevrons

6. AIRFRAME
The airframe consists of the wings, flaps, slats, and landing gear. Although the jet engines are the primary
source of noise, the airframe is also a significant contributor to the total noise signature. The wings
generate noise as “unsteady” airflow passes over them. Flaps and slats are devices mounted on the wings
of a plane and used to control the angle of the plane. They also generate noise as they redirect airflow.

7. NEW DESIGNS
Several new designs have been created to
reduce aircraft noise, such as the SAX-40
and the QSST-X. The Silent Aircraft is a
concept design that is estimated to
reduce aircraft noise by 25 dBA. These
designs work by reducing the weight of
the aircraft and using a triangular shape
to reduce noise. SAX-40

9. IMAGE CREDITS
• Slide 3: Image taken by team.
• Slide 5: "Hush kit" on a Sud Aviation Caravelle" by Mattias Björklund - Licensed under CC BY-SA 3.0 via
Wikimedia Commons and "GEnx-1B on Air India B787 (2)" by Olivier Cleynen - Licensed under CC BY-SA
3.0 via Wikimedia Commons.
• Slide 6: "Wing with one spar" by Dtom - Public Domain via Wikimedia Commons.
• Slide 7: SAX-40 – Silent Aircraft Initiative – Fair use (education).
• Slide 8: Image taken by team.