Boeing patent features new sonic aircraft concept drawing

Photo from US Patent Application, THE BOEING COMPANY, Published April 19, 2012

Boeing has filed a new patent in which it updates its sonic cruiser sketches originally filed with the US Patent office in 2003, though a BCA Engineering spokesperson told “[The] patent is on low noise technology, not a sonic cruiser. The drawing is merely a platform on which to display the technology.”

The new patent application, published April 19, focuses on reducing the level of “roaring” jet exhaust noise, as well as a new engine placement. The new concept drawing included in the patent mounts the aircraft’s nacelles above delta wings with vertical stabilizers outboard of the engines. The design shifts spectrum distribution of exhaust noise from lower to higher frequency, and notes that the aerodynamic structural surfaces are designed to act as noise shielding barriers to block or redirect the noise “up and away from communities.” The aerodynamics of the airplane sketch in the application showcases several adjustments from the file published in 2003—notably in alterations to the wings, canards, fuselage, elevators and engines.

Photo from US Patent, THE BOEING COMPANY, Published June 10, 2003

“Boeing files many patents every year that protect our intellectual property (IP) on various technologies,” the spokesperson told. “This particular patent application is protecting our IP on low noise technologies and does not necessarily mean that Boeing is pursuing development of any particular airframe or program. We are committed to innovation and reducing the noise footprint of our products, which is one of the many environmentally progressive goals we are striving toward.”

Boeing’s Sonic Cruiser was intended to fly at Mach 0.98, just below supersonic speed. Supersonic passenger travel—at or exceeding Mach 1—ended in 2003 following the cessation of Concorde service by British Airways and Air France, and even if the patent demonstrated interest in supersonic speeds,significant barriers remainto reintroducing this type, an expert told.

“The patent addresses only one of the three major issues with supersonic transport aircraft, the first one being noise on takeoff,” Mark Drela, a professor at the Dept. of Aeronautics and Astronautics at the Massachusetts Institute of Technology, said.“Note that the Concorde was incredibly noisy, and had a special exemption from airport noise regulations at Kennedy and Heathrow.  Future supersonic aircraft almost certainly would not have this exemption.”

A second obstacle to reintroducing supersonic flightwould be the greater fuel burn per passenger mile “by roughly a factor of 2.0 to 2.5 over subsonic aircraft. This greater fuel burn is due to basic physics of supersonic aerodynamics, and cannot be eliminated with clever design,” Drela said.

“Third is the sonic boom problem, which affects everybody under the aircraft's ground path, not just near the airports,” he said. “I see the sonic boom problem as the biggest obstacle to supersonic transports because it cannot completely be eliminated, again due to basic physics. Currently, government regulations prohibit any sound boom, no matter how weak, which therefore rules supersonic transports effectively illegal. I get the sense that any attempt to change this to permit sonic booms would be a non-starter politically.”

Article Source : ATW Daily News