Sonic Boom Measurement Techniques
An Armstrong research
effort is focused on demonstrating and validating various innovative methods
for recording and measuring sonic booms. Activities range from collecting data
above and below sonic booms
via a sophisticated
array of microphones to gathering information from remote sensors and
WiFi-controlled microphones strategically placed within communities. The team
is advancing NASA's understanding of how individuals and communities react to
low-noise sonic booms.
Work to date: The team supported the
Farfield Investigation of No Boom Threshold (FaINT) project and
also designed and completed the Waveforms and Sonic boom Perception and
Response (WSPR) project.
For the WSPR effort, the team installed WiFi-controlled
microphones within a 1- to 2-square-mile area on Edwards Air Force Base, then
recorded not only the low-noise sonic booms but also public reaction to them
using written and Web-based questionnaires and a smart phone app.
Looking ahead: Data from the recent
community response pilot study will be valuable for future public
perception studies in communities that do not normally experience sonic booms.
Partners: Participants in the WSPR project included
NASA's Langley Research Center; Wyle; Gulfstream Aerospace Corp.;
Fidell Associates, Inc.; Pennsylvania State University (PSU); and Tetra Tech.
Participants in the FaINT project included Langley, The Boeing Company, Cessna
Aircraft Company, Gulfstream, PSU, Wyle, Dassault Aviation, and the Japan
Aerospace Exploration Agency (JAXA).
Advanced measurement techniques:
FaINT and WSPR projects furthered NASA's knowledge base about sonic boom
recording methods, advanced ground-based microphone arrays, airborne sonic boom
recording systems, and WiFi-controlled sensors and microphones.
polling methods: NASA refined data collection methods and test
protocols for future public perception studies.
Supersonic Flight Research
Supersonic flight over land is currently severely restricted
because sonic booms created by shock waves disturb people on the ground and can
damage private property. Since the maximum loudness of a sonic boom is not
specifically defined by the current Federal Aviation Administration (FAA)
regulation, innovators at NASA have been researching ways to identify a
loudness level that is acceptable to both the FAA and the public and to reduce
the noise created by supersonic aircraft. Using cutting-edge testing that
builds on previous supersonic research, NASA is exploring low-boom aircraft
designs and other strategies that show promise for reducing sonic boom levels.
A variety of factors, from the shape and position of aircraft
components to the propulsion system's characteristics, determine the make-up of
a supersonic aircraft's sonic boom.