|"Chuck Yeager broke the sound barrier ... we just fixed it."
Roy Martin, test pilot,
after the low-boom flight of the F-5E
Chuck Yeager produced the first sonic boom when he broke the sound barrier in 1947. It would then take 56 more years to success-fully demonstrate methods to minimize the clamor produced as a supersonic plane carves its way through earth's atmosphere.
The precursor to current Fundamental Aeronautics work toward a low-boom demonstration aircraft was the Shaped Sonic Boom Demonstration (SSBD) program that included NASA's Langley Research Center and Dryden Flight Research Center along with the Defense Advanced Research Projects Agency (DARPA), Northrop Grumman, and other partners.
Their premise: Change an aircraft's shape, and you can change, and potentially reduce, the intensity of the sonic boom it produces. The SSBD program used a U.S. Navy F-5E modified with a specially shaped "nose glove," an aluminum substructure and a composite skin added to the underside of the fuselage.
Demonstration flights of the F-5E on August 27, 2003, showed a reduction in intensity of the sonic boom produced by the modified fuselage at Mach 1.4. NASA dubbed this the "baby boom." An identical test later in the day confirmed the validity of the SSBD theory. Through these tests, researchers from NASA and other organizations would begin to "fix" the sound barrier that Chuck Yeager had broken 56 years earlier.
As shown above, an F-15B from NASA's Dryden
Flight Research Center measures the supersonic wake
of a modified F-5E during the Shaped Sonic Boom Demonstration. This test proved the viability of low-
boom supersonic flight. NASA photo by Carla Thomas.
In the scene below, microphones and other sensors
pick up low sonic booms that reach the ground during
the F-5E's flight. NASA photo by Tony Landis.