The Return of the Supersonic Airplane

By Alesandro Pellegrino, Staff Reporter, The Pawprint

Almost 20 years after the Concorde failed, civilian supersonic aircraft appeared ready to take off again. New technology is propelling a new generation of aircraft forward, but challenges remain, from regulatory ones to plain old economics.

October 24, 2003, marked the end of an era for the supersonic. That day, the Concorde(the legendary supersonic airliner) made its last commercial flight, flying from London to John F. Kennedy Airport in New York. Since then, no commercial supersonic planes have operated. The futuristic dream of a three-hour flight from London to New York, offered by the Concorde, seemed shattered.

Now, however, nearly 20 years later, we may be returning to that supersonic dream. New technological advances allow new projects to succeed where the Concorde has failed, and several companies and research institutes are investing heavily in a new generation of civilian supersonic aircraft. For example, American company Boom plans to fly a scale model of its supersonic airliner, called Overture, in 2021 and has already raised around $196 million to do so. In addition, NASA pioneered the X-59, an experimental supersonic aircraft that lowers the noise levels of the infamous sonic boom. And Aerion, in partnership with Boeing, is developing a supersonic business jet, which could fly by 2025.

A major thrust behind the resurgence of civilian supersonic aircraft is that they could produce less noise and reduce problems related to sonic booms. When an immobile object, such as a stereo, makes a sound, its sound waves spread in all directions. If visible to the naked eye, these waves would appear similar to those generated when a stone is dropped into a pond.

When a supersonic aircraft reaches speeds higher than the speed of sound, however, it moves ahead of the sound it produces. This causes the sound waves to assume a conical shape, similar to those generated by a sailing boat. As a result, an approaching supersonic plane is almost imperceptible. Still, when it reaches the observer, he is hit by a sudden sound which is similar to a boom of concentrated sound waves. In some cases, these booms can cause damage to buildings, and supersonic military jets flying to land have been known to break window panes. This means that in most countries, routine supersonic flight is prohibited on land, severely limiting the potential routes of a civilian supersonic aircraft. For this reason, the Concorde has always flown over ocean routes.

The intensity of the sonic boom depends mainly on the aerodynamic shape of the plane, shaping the geometry of the plane, the booming volume can be reduced from the more than 100 decibels of the Concorde, similar to listening to a jackhammer, to 70-80 decibels for new designs, about the sound of a vacuum cleaner. For now, civilian low-arm aircraft are still theoretical, even as they are nearing launch. Boom hopes to fly a one-third scale model of its project in 2021, and NASA wants to begin flight tests of the X-59 in 2022. Boom’s new projects with low-boom technology and calls would make the same noise. like that of very distant fireworks. People would still hear it, but not loud enough to break the window. The low boom became possible thanks to advances in tools and research. New computer programs make it easier to simulate aircraft properties and experiment with 3D shapes.