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Supersonic passenger planes could become a reality as new tech quiets the sonic boom

NASA engineers are attempting to get around the problem of sonic booms with a newer, more efficient design

NASA engineers are attempting to get around the problem of sonic booms with a newer, more efficient design

NASA’s first-large scale, piloted X-plane in more than three decades is cleared for final assembly and integration of its systems following a major project review by senior managers held in December at NASA Headquarters in Washington. (Lockheed Martin)

Relief from long airline flights may be on the way as the latest X-plane takes shape, one designed to demonstrate quiet supersonic flight.

The X-59 Quiet Supersonic Technology (QueSST) is the first large-scale, piloted X-plane in more than three decades. The single-seat jet has a unique new shape that will cut through the air at supersonic speed without creating the loud and sometimes damaging sonic booms that come with high-speed flight.

An extremely long nose and specially shaped wings are designed to reduce the shock waves that form around wings when an aircraft breaks the sound barrier. When a conventional aircraft becomes supersonic, the air in front of it cannot get out of the way fast enough, so the air molecules are squeezed together into shock waves that radiate out from the nose, wings and tail. 

Using the schlieren photography technique, NASA was able to capture the first air-to-air images of the interaction of shockwaves from two supersonic aircraft flying in formation. (NASA)

Like the trailing waves of a boat in water, the sonic shock waves form a cone shape that can extend all the way to the ground. The loud booms that result sound like cracks of lightning and can be loud enough to break windows and scare animals, let alone people. 

People don't like loud overhead booms

The damaging effects of sonic booms, and public displeasure over them doomed the only supersonic airliner Concorde from ever becoming a commercial success. Arguably the most beautiful aircraft to ever take to the air and the only passenger jet that could travel at twice the speed of sound, the Concorde was able to cross the Atlantic from London to New York in about three hours, down from eight hours for a regular airliner. It was hailed as a new era of high-speed flight.

By the time the Concorde made its first scheduled supersonic passenger service in 1976, environmentalists protesting against the noise from the plane resulted in regulations that prohibited it from flying at supersonic speeds over U.S. soil. This meant that Concorde was restricted to ocean crossings and could not offer super fast transcontinental service to the very lucrative California market.

On March 2, 1969, the first Concorde took to the air from Toulouse, France. Only 20 Concordes were built, with 14 going into regular service with Air France and British Airways, including the G-BOAG. (BAE Systems)

While 14 Concordes flew for nearly three decades, setting many aviation records for speed, altitude and distance, it also happened to appear on the scene when fuel prices skyrocketed, so tickets for flights were astronomically high and it never regained its development costs.

Engineering a quieter supersonic boom

Now NASA engineers are attempting to get around the problem of sonic booms with a newer, more efficient design. 

The X-59's very long pointed shape is intended to cut through the air more efficiently so the shock waves are minimized. In fact, the nose of the plane is so long, there isn't even a forward facing window. The pilot will rely on a 4k monitor to see ahead.

The designers hope people on the ground will hear nothing more than a mild thump, if they hear anything at all. To find out, the experimental plane will be flown over populated areas and surveys will be taken with people living below to determine how disturbing the sounds actually are.

Testing the External Vision System (XVS) software on the B200 King Air. Pilots Peter Coen and Wayne Ringelberg attempt to spot an incoming aircraft on the XVS monitor. (NASA Langley / David C. Bowman)

The goal is to ultimately bring supersonic flight back to the airline industry. Since the Concordes were grounded in 2003, airliners have been built for comfort rather than speed with fully reclining chairs and even full sleeping cabins with double beds. This is to compensate for the fact that many international flights now last up to 18.5 hours thanks to a new generation of super-efficient planes. If those flights could be cut in half, it would be a tremendous improvement for both passengers and crew.

New future of supersonic flight

New supersonic airliners are being developed, one of them ironically named Boom that will be more efficient than the Concorde, flying, for example, between Sydney, Australia and Los Angeles in 6 hours 45 minutes instead of the current 15 hours. 

At the moment, these planes will be flying over oceans. But if quiet technology can be incorporated into their design, we could see supersonic travel everywhere. 

Now if they could just take care of the long waits at the airports...

ABOUT THE AUTHOR

Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC-TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.

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