NASA building demo quiet supersonic airplane by 2022
NASA plans to share the technology resulting from the tests with U.S. plane makers, meaning a head start for the likes of Lockheed Martin, General Dynamics, Boeing, and startups such as Boom Technology and billionaire Robert Bass's Aerion.
Lockheed helped create NASA's design, using fluid dynamics modeling made possible in the past decade or so by increasingly powerful computers. Together, Lockheed and NASA tested and mapped how subtle differences in aircraft shapes affect the supersonic shock waves they create. The design they've settled on keeps sound waves from merging into the sharp N pattern of a sonic boom, according to Peter Iosifidis, Lockheed's design program manager on June's small-scale model. Instead, the waves are kept dispersed across a wide range of points behind the plane, leaving the resulting supersonics a mere hum.
NASA is targeting a sound level of 60 to 65 A-weighted decibels (dBa), Coen says. That's about as loud as that luxury car on the highway or the background conversation in a busy restaurant. Iosifidis says that Lockheed's research shows the design can maintain that sound level at commercial size and his team's planned demo will be 94 feet long, have room for one pilot, fly as high as 55,000 feet, and run on one of the twin General Electric Co. engines that power Boeing Co.'s F/A-18 fighter jet.
The Concorde had 90 dBa (about 1000 times louder).
