{"id":13562,"date":"2025-02-14T10:00:00","date_gmt":"2025-02-14T10:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=13562"},"modified":"2025-02-04T02:58:47","modified_gmt":"2025-02-04T02:58:47","slug":"supersonic-jets-comeback-february-2025","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/supersonic-jets-comeback-february-2025\/","title":{"rendered":"Supersonic jets are making a comeback \u2013 but despite the hype, don\u2019t expect to book yet"},"content":{"rendered":"\n
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\n Rendering of Boom Supersonic\u2019s proposed Overture supersonic airliner.\n Boom Supersonic<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n Chris James<\/a>, The University of Queensland<\/a><\/em><\/span>\n\n

Late last week, American company Boom Supersonic flew faster than the speed of sound with its XB-1 supersonic demonstrator aircraft. It\u2019s now the first piloted non-military aircraft to break the sound barrier<\/a> since the Concorde was retired from service in 2003. <\/p>\n\n

It\u2019s the first step in Boom\u2019s ambitious goal to have supersonic airliners carry passengers by 2029<\/a>.<\/p>\n\n

But what exactly is supersonic travel? There are good reasons why it\u2019s not more common, despite the hype.<\/p>\n\n

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\n Boom Supersonic\u2019s XB-1 supersonic demonstrator aircraft during its 11th test flight where it became the first civilian aircraft to fly supersonically since the Concorde.<\/span>\n Boom Supersonic<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

What is supersonic flight?<\/h2>\n\n

The Mach number is defined as a plane\u2019s speed divided by the speed that sound waves move through the air. To \u201cbreak the sound barrier\u201d means to fly faster than the speed of sound, with Mach numbers greater than 1.<\/p>\n\n

The Mach number is an important ratio: as a plane flies, it disturbs the air in front of it. These disturbances move at the speed of sound. In supersonic flight these disturbances combine to form shock waves around the vehicle.<\/p>\n\n

When people say you can see a fighter jet before you hear it, they\u2019re referring to supersonic flight: fighter jets can travel at around Mach 2<\/a>. <\/p>\n\n

The sound from the fighter jet is trapped inside its shock wave; until the shock wave moves to your position on the ground, you won\u2019t hear the plane.<\/p>\n\n

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\n Illustration of how disturbances propagate in subsonic, Mach 1, and supersonic flow.<\/span>\n Chabacano\/Wikimedia Commons<\/a>, CC BY-SA<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

The allure of supersonic travel<\/h2>\n\n

For efficiency reasons, most passenger jets cruise slightly slower than the speed of sound, at around Mach 0.8 (this is subsonic flight).<\/p>\n\n

Boom plans to build an airliner called Overture<\/a> that can fly at Mach 1.7. Flying supersonically can drastically decrease flight times. The company claims a trip from New York to Rome<\/a> on Overture could take just four hours and 40 minutes, instead of eight hours.<\/p>\n\n

Boom isn\u2019t the only company working on this lofty goal. American firm Spike Aerospace is also developing a supersonic business jet, with the tagline<\/a> \u201cdelivering the world in half the time\u201d.<\/p>\n\n

This is the value proposition of supersonic passenger travel. <\/p>\n\n

In limited ways, it did already exist in the 20th century. However, due to timing, bad luck and the laws of physics, it didn\u2019t continue.<\/p>\n\n

Remember the Concorde?<\/h2>\n\n

Designs for supersonic airliners began in the mid-20th century, and by the 1970s we had supersonic passenger flight.<\/p>\n\n

There was the little-known Russian Tupolev-144<\/a> and Concorde<\/a>, a Franco-British supersonic airliner operated by British Airways and Air France from 1976 to 2003.<\/p>\n\n

Concorde had a capacity of up to 128 passengers<\/a> and cruised at Mach 2. It regularly travelled from London to New York in around three hours<\/a>. The flights were expensive, mainly shuttling business people and the rich and famous. <\/p>\n\n

\n \"A<\/a>\n
\n British Airways Concorde in flight.<\/span>\n Wikimedia Commons\/Eduard Marmet<\/a>, CC BY-SA<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

Why supersonic passenger flight didn\u2019t take off<\/h2>\n\n

Concorde was designed in the 1960s when it seemed like supersonic passenger transport was going to be the next big thing.<\/p>\n\n

Instead, the Boeing 747 entered commercial service in 1970<\/a>. Cheap, large and efficient airliners like it blew Concorde out of the water.<\/p>\n\n

Designed to cruise efficiently at supersonic speeds, Concorde was extremely fuel inefficient when taking off and accelerating. Concorde\u2019s expensive, \u201cgas guzzling<\/a>\u201d nature was a complaint levelled against it for most of its lifetime.<\/p>\n\n

A catastrophic 1973 Paris air show crash<\/a> of the competing Russian airliner, Tupolev Tu-144, also shifted public perception on supersonic flight safety at a time when many airlines were considering whether or not to purchase Concordes.<\/p>\n\n

Only 20 Concordes were manufactured<\/a> out of the planned 100<\/a>. It is still disputed today whether Concorde ever made money for the airlines who operated it<\/a>.<\/p>\n\n

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\n Illustration of a shock wave propagating from a supersonic aeroplane and hitting the ground to produce a sonic boom.<\/span>\n Cmglee\/Wikimedia Commons<\/a>, CC BY-SA<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

Noise is a real problem for supersonic flight<\/h2>\n\n

Remember the fighter jets? When a plane travels supersonically, its shock waves propagate to the ground, causing loud disturbances called sonic booms<\/a>. In extreme cases they can shatter windows and damage buildings.<\/p>\n\n

In the early 1970s, sonic boom concerns led the United States government to ban supersonic passenger flight over land in the US<\/a>. This hurt the Concorde\u2019s potential market, hence its only two regular routes were trans-Atlantic flights principally over the water.<\/p>\n\n

The Concorde was also a very loud plane at take off, since it needed a lot of thrust to leave the ground.<\/p>\n\n

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