What It Means to Go Supersonic: The Return of Supersonic Airliners

 Commercial supersonic aircraft will become cheaper and more efficient after 20 years without any in service. This is what the return of supersonic air travel means and how it will revolutionize aviation. 

The Tupolev Tu-144 and its distinctive canards behind the cockpit for low-speed handling; Source: UK Aviation News

At the beginning of the jet age, there was one rule: make airliners bigger and faster. Think of the 747, which still fascinates avgeeks across the globe whenever one lands or departs an airport. Early quadjets like Convair’s Coronado or the 707 could reach speeds as fast as 1000kph (540kt), close to the speed of sound! 

However, the hype that came with the jet age didn’t stop there. From then on, it was just getting faster, and by the 1960s the first supersonic airliners were in the making. The wonder came on New Year’s Eve 1968, when Tupolev’s Tu-144 accomplished its maiden flight. 

Just two months later, the legendary Concorde flew for the first time. The Tu-144 reached supersonic state on June 5, 1969, and a year later became the world’s first commercial aircraft to exceed Mach 2. 

However, in the international race to build a supersonic airliner, it quickly became evident that the rush to produce resulted in deadly mistakes. 

In 1973, Concorde and the Tu-144, or “Concordski” as it became known, both participated in the Paris Air Show. While the crew of the Concorde enchanted the public with a classic display of the aircraft’s capabilities, the Tu-144 crew really wanted to show off. 

The plan was for two low passes before circling back to land on the runway. However, on final approach, the aircraft returned into a full-afterburner climb, levelling at 4’000ft. Shortly after, it went into a steep dive. The forces stressed the aircraft so much it disintegrated mid-air, dooming it to crash. 

14 people died, and 60 more suffered injuries. 

Flight profile of the doomed Tu-144 at the Paris Air Show; Source: Wikipedia

As Tupolev scrambled to improve the aircraft’s record, Concorde made a headstart with airlines, mainly with Air France and British Airways. As Concorde’s popularity rose, it became clear that the Tu-144 couldn’t compete. 

The aircraft didn’t stay in commercial use for long, but this time was riddled by problems; the Tu-144 experienced everything from depressurization events to engine failures. The passenger comfort also wasn’t the best — because the Tu-144 could only sustain supersonic flight with continuous afterburners, it was extremely loud in the cabin. 

Many reasons for customers to avoid flying with the Tu-144. 

In 1978, the aircraft was involved in another fatal crash after a fuel leak that led to an in-flight fire and engine failure near Yegoryevsk in Moscow Oblast. Of the eight people on board, two died. 

It didn’t take long until the Tu-144 program was cancelled. It stayed in use until 1999 for astronaut training for the Buran spaceplane, as well as for supersonic research. 

British Airways Concorde seen on take-off; Source: Wikipedia

And as great as Concorde was — infamously flying from London to New York in less than three hours, a record it broke in 1996 — it doesn’t have a clean record. The crash that killed 113 people, Air France Flight 4590, is close to reaching its 24th anniversary. Concorde crashed into the suburbs of Paris after striking debris on the runway left by a Continental DC-10 that instigated an in-flight fire. 

The global fleet of Concorde aircraft was grounded following the crash, but cleared to fly again in November 2001. But at that point, there was no turning back to its days of glory. People were avoiding air travel following the 9/11 attacks, and Concorde was no longer technologically advanced. 

Concorde’s technology became old school as fly-by-wire dominated modern aircraft, pioneered by the A320. In 2003, Airbus decided to stop resupplying parts of Concorde. Slowly but steadily, Concordes disappeared from the sky. 

The last time a Concorde flew was on November 26, 2003. 

In the 20 years since its last flight, we’ve never again seen anything comparable to Concorde. The age of the supersonic airliner came to a halt. Manufacturers instead focused on making airliners more efficient — making them more affordable and easing the toll aviation has on the environment. 

Jumbo jets like the 747 are disappearing from airlines and are converted to freighters, shipping mail and goods around the world. Quadjets such as the A340 are exchanged for the newer A330neo or A350 family, and narrow body aircraft become quieter. 

Amid the aviation shift, some minds turn to the old — very soon, supersonic airliners will make a return. Active development is happening, and the ambitions for future supersonic airliners become even greater than for historic legends like Concorde. 

One of the biggest challenges in constructing a supersonic airliner is sound. Many people used to complain about Concorde’s noise as it broke the speed of sound, its sonic boom reverberating on the ground. In addition, a lot of countries don’t permit sonic booms over land. 

The X-59's unique design aims to make sonic booms quieter; Source: Wikipedia

Making supersonic aircraft quieter

Earlier this year, NASA’s Quesst Mission and Lockheed Martin’s Skunk Works presented the X-59, an experimental supersonic aircraft that aims to make supersonic air travel quieter. The maximum speed of the aircraft is about Mach 1.5, cruising at 55’000ft. 

While Concorde’s ground noise during sonic boom reached 105 to 110 EPNdB, the sonic boom of the X-59 is planned to be as silent as 75 EPNdB. 

The jet will lay the groundwork for future supersonic airliners once all the research and tests are finished. Quieter supersonic flight also means that aircraft would be allowed to fly faster — perhaps up to Mach 4, which would make transatlantic flight a short endeavor. 

Boom's XB-1 has just finished its first flight; Source: Boom Supersonic

A new supersonic airliner with a reminiscient design

Just a month ago, Boom’s XB-1 took off for the first time in the Mojave Desert, demonstrating its abilities in the company’s race to build the Overture. The Overture would become the next Concorde; flying at Mach 1.7 and seating up to 80 passengers, Boom aims to introduce the jet by 2029 with the right funding. 

The Overture’s design resembles the scrapped 2707, Boeing’s unsuccessful attempt at building a supersonic airliner in the ‘70s. It’s a quadjet like Concorde, but these engines would be placed as four large external engine pods. 

Design concept for the Overture; Source: autoevolution

The Overture also has the horizontal stabilizers which Concorde lacks. United Airlines and American Airlines both already placed orders for the Overture, summing up to 35 orders in total. 

While the Overture is also restricted to sonic booms over water, the jet would still be able to fly faster over land than subsonic aircraft, reaching Mach 0.94 without breaking the sound barrier. In comparison, an A320 cruises at about Mach 0.78. 

So far, the Overture still faces challenges that the XB-1 hopes to solve by active flight testing — after all, the best teacher is experience. What the Overture faces is also a problem that Concorde had: the requirement for long runways, as supersonic aircraft need a lot of thrust on take-off. There’s also a nose-up attitude based on the current design that could become problematic during landing. 

Design concept of Boeing's 2707; Source: Wikipedia

However, once these challenges are solved, there’s nothing in the way for the return of supersonic airliners. 

We’re in the midst of a breakthrough — one defined by airliners soon breaking through the sound barrier in the race to reaching transoceanic destinations in record time. All the while, these aircraft will become quiet birds travelling at altitudes only mastered by Concorde.

Thank you for reading my article! If you would like to support a young writer, please check out my Ko-fi!

Check out my other blog about space here!