The Boom Stops Here
Hush, hush, sweet SST. Engineers are inventing a supersonic airplane that won't bust windows.
- By T.A. Heppenheimer
- Air & Space magazine, November 2005
(Page 4 of 6)
About a year ago, NASA assembled an alliance of companies called the Super 10—“super” for supersonic and “10” for the 10 industry giants, including airframers and engine companies—and asked them to evaluate a direction for supersonic research and recommend areas that would yield the highest payoff. The group recommended NASA support building a sonic boom flight demonstrator. “There are two important pieces of the program,” says Meyer, who is leading the Boom Demonstrator project for NASA’s Aeronautics Research Mission Directorate. “The first task is to take the design tools developed over the years, validate them with flight demonstrator data, and determine if we really can propagate a low-boom shock wave to the groundfrom an entire airplane at supersonic speeds. The next step will be to use that data to change the current regulations prohibiting supersonic flight over land.”
The length of the piloted demonstrator airplane will be about 80 to 100 feet. “Hopefully, this will be a stepping stone to a larger demonstrator sometime in the future,” says Meyer. “We also have a lot of challenges for supersonic cruise aside from low-boom that we have to address in parallel with the demonstrator, including propulsion, inlets, laminar flow, and materials, just to name a few.” Managing fuel consumption is obviously still a hurdle as well. He adds that the program will be more than just the sum of its test flights: “There will be a lot of analytical work performed, from computer codes to ground work, including wind tunnel tests.”
Boom acceptability work will include “boom boxes,” booths like those used for hearing tests, in which people will experience a replicated sonic boom and then rate the strength of the sound and their reaction to it. “We’ll also rate what we call the indoor response,” adds Meyer, “that will tell us how a boom feeds through a structure and how it affects people inside buildings. These tests will be more complex than outdoor response tests.”
Ultimately, NASA hopes to take its low-boom aircraft beyond the constraints of Edwards’ supersonic corridors and over more populated areas. “We want to expose the cities to the reduced sonic boom and see if they even notice it,” says Meyer.
“We had a lot of grey hair on this project,” says Graham. “When we [at Northrop Grumman] first started working with Dominic [Maglieri], he sent us a résumé that said he had 45 years of experience in sonic booms. I thought it was a typo, but it wasn’t.” There’s a certain triumph in working decades on one goal and finally seeing a pay-off. And in 2008, if NASA’s newest X-plane streaks over New York City at Mach 1.2—quietly—engineers will finally reap the rewards of all those years of research.
Dennis Shoffner has heard it all. “I want to make a formal complaint about what these sonic booms are doing to my physical body,” declared one irate caller. “I moved to Barstow over a year ago, and I wasn’t obese back then.” She went on to claim that the sonic booms to which she had been subjected in the past 12 months were making her fat. Shoffner listened politely, held in his laughter, and referred the call to the claims department. “A half-hour later, they chased me down the hall for sending them that phone call,” he remembers.
Shoffner is the chief of community relations at Edwards Air Force Base in California. Since 1998, he’s been fielding aircraft noise and sonic boom complaint calls from residents in the surrounding counties. Under his guidance, the complaint line has morphed into a “query” hotline because, believe it or not, not all the calls are negative. Sometimes people just want to know what kind of airplane just went boom over their house. Shoffner spends much of his time visiting nearby communities, attending meetings, and giving out his work phone number to everyone he meets. “What I found out when I went to talk to people is that they felt barraged with noise and ignored by us [at Edwards],” says Shoffner. “There’s a science to dealing with the calls. These people are in the mood to talk, not to listen.