For decades, the sound of sonic booms has been heard over the Antelope Valley from military jets and the Space Shuttle.
But now, Lockheed Martin Corp. is developing at its top-secret Skunk Works plant in Palmdale an experimental aircraft that will minimize the noise created when it flies faster than the speed of sound.The technology could revolutionize commercial aviation by cutting the flight time for long trips in half. And between Lockheed Martin and several subcontractors, the Valley region is the launching pad for this fledgling technology.The X-59 Quiet SuperSonic Technology aircraft is unique within Lockheed Martin in that it is an unclassified program being developed and built at the Skunk Works. That is where the company’s classified programs take place in a veil of secrecy.
The Bethesda, Md. aerospace and defense firm received a nearly $248 million contract three years ago from NASA to develop, build and test the X-59.David Richardson, program manager for the X-59, said that the goal of the airplane is for it not to make a sonic boom.
“It is a quiet sound rather than a loud smack,” Richardson said of what happens when the aircraft flies past the sound barrier. “It is like a loud thump.”Mike Buonanno, chief engineer for the aircraft, explained how it will minimize the boom.
Supersonic aircraft create shockwaves that all merge together to create a pair of very large waves heard as a sonic boom. The design of the X-59’s exterior alters the size and spacing of those shock waves.
“Instead of all merging together for the large double bang, they are able to attenuate in the low atmosphere and kind of smear together and that dramatically reduces the loudness that is perceived on the ground,” Buonanno explained.
The first flight of the X-59 was supposed to take place this year but that has been pushed to next summer.
One reason for the delay is the coronavirus pandemic. At Lockheed Martin, it put the program behind by two months, Richardson said. Because the X-59 is an unclassified program most of the staff on it were able to work from home, he added.Noise comparisonsAs for why NASA is funding the research, agency spokeswoman Sasha Ellis said people often forget that the first “A” in NASA stands for “aeronautics.”“Every U.S. commercial aircraft and U.S. air traffic control tower has NASA-developed technology on board that helps improve efficiency and maintain safety,” she said in an email. “NASA Aeronautics has made decades of contributions to aviation to persistently and consistently improve environmental sustainability, global mobility and economic growth. Part of the agency’s efforts include innovation in commercial supersonic aircraft.”The airline industry would be the prime beneficiary of technology developed by the X-59 program, as opposed to military use. “The sonic boom shaping element is really only relevant to commercial supersonic (planes),” Buonanno said. “There is really no military applicability of the sonic boom shaping technology.”If the military were to use it, Richardson added, it would be in an executive transport setting, such as with Air Force One, the plane the president travels in.
“(For) the planes used to transport congressional leaders and military leaders, this would be something that they would want to use,” Richardson said. “Otherwise, this does not present any tactical military advantage.” Tests conducted by NASA determined that a level of 75 perceived decibels, or PLdB, was adequate; people in the tests said they could live with that, Richardson continued.
The challenge that NASA gave Lockheed and other aerospace companies vying for the contract was to design a plane with a sonic boom of 75 PLdB or less, or the equivalent of a car door slamming from 20 feet away.
By comparison, the Concorde, the last commercial supersonic jet, generated 105 PldB, according to NASA. Distant thunder is about 73 PLdB, a basketball bouncing is about 90 PLdb and a hand clap is about 95 PLdB.
After flight tests at NASA Armstrong Test Research Center at Edwards Air Force Base in the Antelope Valley, the X-59 will go to about six locations around the country for additional flights, ranging from large cities to rural environments.These areas will be informed ahead of time that an X-59 flight will occur, but they won’t be told the exact time, Richardson said.
Thus, millions of people will be exposed to the test flights who can provide feedback on their perception of noise from the X-59, Buonanno said.“There is going to be a rich data base to draw from,” he added. “Using the data from this community response, we’ll be able to establish a threshold where there is some low level of loudness where everyone will accept it.” The data will be shared with Federal Aviation Administration officials and other regulators to change the rules that prohibit supersonic flight over land in the U.S. and other countries.
Valley subcontractorsRichardson estimated that between 300 and 350 Lockheed employees have worked on the X-59 project. Add in NASA employees and workers from the many suppliers and that number can go up to about 1,500, he added.
Suppliers to the program are spread across the country and even in the United Kingdom and Canada. Most, however, are in Southern California, with eight of the companies located in the San Fernando or Santa Clarita valleys.
Among them are EON Instrumentation Inc. in Van Nuys; Forrest Machining Inc. in Valencia; Embe Industries Inc. in Glendale; and Senior Aerospace SSP in Burbank.Eon, a veteran-owned military contractor, announced in February it had supplied two additional high-speed dual-redundant DisplayPort active switcher/converters to NASA for the X-59. The first piece of equipment supplied by Eon was done in September. When built, the X-59 will be 100 feet long with a wingspan of 29.5 feet. The aircraft has a 30-foot-long pointed nose that prevents a forward-looking window for the pilot to see out of. So, NASA got supplier Collins Aerospace to make a custom large format display system that allows the X-59 pilot to safely fly by using a 4K monitor to display images from two cameras outside the aircraft.An operational civilian airplane would be significantly larger than the demonstration version, Buonanno said.It could be up to 200 feet long, he added, which was the length of the Concorde, the supersonic commercial jet that flew commercially from 1976 to 2003. The Concorde could accommodate 92 to 128 passengers.
The plane will fly at about Mach 1.4, a bit slower than what the program hopes an operational supersonic commercial aircraft will achieve, at about Mach 1.8, Buonanno said.Richardson called the Mach 1.8 speed “a magic number” as it is twice as fast as current commercial jets.
“If you are flying to Japan or even from Los Angeles to New York, you will be in the airplane for half the time that you are today,” Richardson noted.
Both Buonanno and Richardson said that operational supersonic commercial jets would not become available until about 2035.
Supersonic ‘Clap’
