The next generation of aircraft could be thinner and lighter thanks to the development of a nonlinear acoustic imaging technique that can detect damage previously invisible to acoustic imaging systems. According to Dr. Jack Potter, research assistant in the department of mechanical engineering at the University of Bristol’s Ultrasonics and Non-destructive Testing research group, it has long been understood that acoustic nonlinearity is sensitive to many physical properties including material microstructure and mechanical damage.
Airport noise can be an emotionally volatile issue in municipal politics. However, Robert Grotell thinks data, not emotion, should drive decisions about airport and air route noise abatement.
In a move that could help pave the way for low-boom supersonic flight over land, NASA aeronautics researchers are presenting their work on how people on the ground perceive low sonic booms this week in Atlanta at an annual event held by the American Institute of Aeronautics and Astronautics. “Lessening sonic booms is the most significant hurdle to [civil] supersonic flight,” said Peter Coen, head of the high-speed project in NASA’s aeronautics research mission directorate at the agency’s headquarters in Washington, D.C.
Aerion announced today at EBACE that it is redesigning its proposed supersonic business jet (SSBJ) with a larger cabin and more range, reflecting feedback from a recent survey of potential operators. The new aircraft–dubbed AS2, for Aerion supersonic second design–has three as yet unspecified engines versus the two P&W JT8Ds intended for its now-scrubbed predecessor.
Business aircraft cabins are generally not quiet. Not with the turbulent boundary-layer rush of air around the fuselage at Mach 0.85 and the whine of a couple of jet engines no great distance from the comfy chairs. Then there are the pumps, hydraulics, fans, gears, actuators, electric motors, worn bearings and air distribution through the metal ductwork, not to mention the occasional hum of the microwave and induction oven, the rattling of glasses and flatware in the galley and that giant sucking sound coming from the lavatory.
Alto Aviation, a supplier of business jet cabin audio systems, is urging completion and refurbishment centers to rethink speaker grille construction.
“It is one of the most common problems we encounter,” according to the Leominster, Mass.-based company. “Sound waves are made up of the compression and expansion of air [and] if air can’t move through the speaker grille, then the sound can’t get into the cabin.”
Alto recommends speaker coverings that are at least 50-percent open to ensure the best audio performance.
Missouri senator Claire McCaskill (Democrat) hit the nail on the head when she wrote to the FAA about easing rules on the use of portable electronic devices (PEDs) in aircraft. Her letter seeks to have the FAA reconsider restrictions on PEDs, citing as one example the fact that many airline pilots are now using switched-on iPads during taxi, takeoff and landing without any problems.
The supersonic business jet development program continues at Gulfstream Aerospace, but until the FAA decides to define “quiet” as it relates to the so-called sonic boom, “We just don’t see a business case,” said a spokesman.
In a series of patent filings last summer, Gulfstream emphasized mitigating the noise produced by the sonic boom, pointing out that regulations currently prohibit supersonic flight over populated areas.
With the clock ticking toward the start of next year’s World Cup soccer tournament in Brazil, construction is set to begin on São Paulo’s first business airport, which is expected to help handle the influx of private aircraft for the event. Approximately 40 miles from the city, vegetation has been cleared from the future site of the Catarina Aeroporto Executivo’s 8,100-foot main runway and a shorter companion, and bulldozers are scheduled to arrive mid-month when earthmoving permits are issued.
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