Future aircraft design and impact

A summary of the 22nd Workshop, 6 September 2018 at NLR, Amsterdam

by Wouter Looman

1.      Future aircraft design

  • Engines on top will reduce aircraft noise enormously (no reflection on wings).
  • Nice figures about the possible decrease of dB’s in the coming twenty years, like 51 dB below stage 4 in 2035.
  • Happily at the moment they are not able to build supersonic aircraft as chapter 3.
  • The technicians at the conference don’t believe in electric aircraft: it was no subject.
  • Noise reduction with Boundary Layer Ingestion: engines as part of the fuselage; models show possibilities, but don’t achieve the NASA midterm goals of a reduction with 32-42 dB.
  • There are serious gains possible with redesigning landing gear and flaps (reference article).
  • But all measures together don’t achieve the NASA goals of a reduction with 32-42 dB in 2030.
  • Overall: today’s computer modelling shows what is possible and what not, instead of all trial and error.

2.      Noise impact

  • References to Aviation Noise Impact, Basner e.a. 2017 (non-acoustic factors, sleep disturbances, learning processes, health impact).
  • Nuisances differ from complaints.
  • Lden versus frequencies versus peeks.
  • Watch out for low-boom of new generation supersonic aircraft.
  • Real weather prognoses qua impact of wind for noise forecast in Sweden (CSA – SAFT).
  • US: although the number of people that suffer are only 5% of the number in earlier years, the number of concerned people has grown.
  • In early days little flights with much noise, now many flights with less noise; not by definition better.
  • More precise navigation drives people under the flight paths mad.
  • “Put a loudspeaker under the aircraft with music only +10dB”.