Is a silent supersonic aircraft possible? NASA’s X-59 is in the kitchen

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“A sonic boom rattled the window panes of the city. It was the sound of a supersonic plane, one of the few still flying in those days. People stopped to look up at the sky, surprised to see such a powerful and fast aircraft, something that had been a rarity in recent years,» writes the chat artificial intelligence ChatGPT-3.

Break the sound barrier without crossing the sky

2023 is the year that a sleek new supersonic plane, endorsed by NASA, will take to the skies with passengers on board. But X-59 it will not bring down the glass of city buildings again as described by ChatGPT-3. Artificial intelligence has not taken into account in its story that the technological prodigy of the expected airplane is its silence. Breaking the sound barrier without crossing the sky is a challenge in testing.

X-59 will fly to Mach 1.42, which is equivalent to about 1,760 km/h, about one and a half times the speed of sound, and is the first prototype of a future commercial airplane. At the moment it has capacity for a single pilot and an observer, but the plan is that in 2030 it will carry passengers on board. For example, we will travel between Madrid and Paris in half an hour, and we will cross the Atlantic in four. Space and time will have been compressed.

The reasons for the sonic ‘boom’

Supersonic planes met the challenge of traveling faster than sound in the 1940sand that, which is a feat, makes them one of the most thunderous machines created by the human being

The speed of sound is the speed at which pressure oscillations are transmitted in a fluid, in this case air. It depends on several factors, but at sea level it is about 1,234 km/h.

The phenomenon occurs when a particle collides with the one next to it, and this one with the next, etc., transmitting the vibratory state as if pieces of a domino. If an object like the plane moves in the air, it makes noise. But if this object moves faster than the sound transmission waves, then a shock wave (which makes a lot of noise) is produced and generates what we know as a sonic boom or boom sonic.

The white disk that forms is nothing more than water vapor condensing as a result of the shock wave. This phenomenon is known as Prandtl–Glauert singularity.

The noise generated by supersonic planes is so disturbing that their flight over urban areas or protected spaces is not allowed, because it also affects flora and fauna.

In addition, they also have against them that they require a large amount of fuel to reach and maintain high speeds, which makes them more expensive and less ecological than the subsonic flights. And the commercial failure of the Concorde, finished off by the accident of his last flight with Air France.

The key: its silent geometry

NASA has spent years working to mitigate these problems and its answer is the X-59 QueSST aircraft, a working prototype manufactured by the Lockheed Martin aerospace company.

This is a ship with a swept wing span of 29 meters and designed to fly about 55,000 feet (16.8 km) above sea level.

Its design is the result of innumerable virtual simulations that allow hundreds of designs to be analyzed in computational fluid models (CFD for its acronym in English). Every little detail of the plane can ruin its silent geometry.

For example, the fuselage is very long and penetrating, and it does not have the typical cockpit that we are used to. A normal airplane cockpit would break the flow and create noise, so the X-59 pilot views the sky through a monitor.

The swept wing allows it to penetrate the atmosphere smoothly. The tail contains the GE F414 engine at its top, and this is also not accidental. Each of these details counts. so that contributions to boom sonic are small and separate and they disperse as the plane moves awayinstead of coalescing (joining) as usually happens in supersonic aircraft.

There is a virtual sound of the X-59 that is used to test it, and determine if it meets the requirements established by the FAA(Federal Aviation Administration).

Its smaller size and improved cycle engine make it more fuel efficient and less polluting than other supersonic aircraft. In addition, it is equipped with formation flying technology, which allows it to fly alongside other aircraft to reduce air resistance and improve fuel efficiency.

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With all these improvements, NASA hopes to pave the way for supersonic commercial aviation again, this time to stay. Will he get it? The first test flight is expected this year. Let’s not miss the appointment.

This article was originally published on The conversation. read the original.

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